Paper Teknik Operasi Trepanasio

TUGAS MAKALAH KELOMPOK ILMU BEDAH KHUSUS VETERINER
“Teknik Operasi Trepanasio”
OLEH:
Kelompok 4 Kelas 2016 D
Maria Anastasia Hutapea
1609511076
Derfina Lijung
1609511078
Raisis Farah Dzakiyyah A.
1609511080
LABORATORIUM BEDAH KHUSUS VETERINER
FAKULTAS KEDOKTERAN HEWAN
UNIVERSITAS UDAYANA
DENPASAR
2019
RINGKASAN
Trepanasio atau trepanasi adalah operasi membuka suatu rongga yang
berdinding keras, misalnya tulang dengan menggunakan alat trepan. Misalnya
pada operasi sinus di daerah kepala atau operasi pada liang (rongga) sumsum
tulang. Trepanasi sinus dilakukan untuk tujuan pengobatan emphyema, neoplasma
dan tumor pada sinus; membantu dalam usaha pencabutan gigi pada kuda; dan
untuk tujuan operasi diagnostik. Jenis-jenis operasi trepanasio pada hewan dapat
dibedakan berdasarkan tempat atau daerah yang akan dilakukan proses
pembukaan rongga tersebut. Operasi trepanasio sering dilakukan pada hewan
besar, antara lain untuk membuka sinus maxillaris mayor, sinus maxillaris minor,
sinus choncho frontalis, sinus frontalis, rongga hidung dan rongga-rongga pada
rahang bawah. Prosedur dari pelaksanaan operasi trepanasio dapat bervariasi
tergantung pada kondisi dari hewan tersebut. Persiapan bedah trepanasi mencakup
merestrain pasien dalam kandang jepit serta menggunakan halter. Selanjutnya
dilakukan insisi sedalam kulit dan tulang dengan lebar sayatan disesuaikan ukuran
trepan. Insisi pada kulit dapat ditutup dengan staples atau jahitan tunggal.
Perawatan pasca operasi trepanasi tergolong minim.
Kata Kunci : Trepanasio, Sinus
ii
SUMMARY
Trepanasio or trepanation is the operation of opening a hard-walled cavity,
such as bone using a trepan tool. For example in sinus surgery in the head region
or surgery on the burrow (cavity) bone marrow. Sinus trepanation is performed
for the purpose of treating emphyema, neoplasms and tumors of the sinuses;
assisting in tooth extraction in horses; and for diagnostic operation purposes. The
types of trepanation operations in animals can be distinguished based on the
place or area to be carried out the process of opening the cavity. Trepanasio
surgery is often performed on large animals, including opening the major
maxillary sinus, minor maxillary sinus, choncho frontalis sinus, frontal sinus,
nasal cavity and cavities in the lower jaw. The procedure of implementing
trepanation operations can vary depending on the conditions of the animal.
Preparation of trepanation surgery involves restraining the patient in a pinch
cage as well as using dumbbells. Next, an incision made as deep as the skin and
bone with the width of the incision adjusted to the size of the trepan Skin incisions
can be closed with single staples or sutures. Postoperative treatment trepanation
is minimal.
Keywords : Trepanation, Sinus
iii
KATA PENGANTAR
Puji syukur penulis panjatkan kepada Tuhan Yang Maha Esa karena atas
berkat dan rahmat-Nya lah penulis dapat menyelesaikan makalah ini tepat waktu
dengan judul “Teknik Operasi Trepanasio“. Makalah ini dibuat guna memenuhi
tugas mata kuliah Ilmu Bedah Khusus Veteriner Fakultas Kedokteran Hewan,
Universitas Udayana yang akan dijadikan sebagai landasan dalam penilaian
softskill pada proses pembelajaran.
Tidak lupa penulis ucapkan terima kasih kepada dosen pengampu mata kuliah
Ilmu Bedah Khusus Veteriner untuk segala bimbingan dan dukungannya serta
kepada segala pihak yang turut dalam membantu pembuatan makalah ini sehingga
makalah ini dapat selesai tepat pada waktunya.
Penulis menyadari bahwa makalah ini masih banyak kekurangan baik dari
segi materi, ilustrasi, contoh, maupun sistematika penulisan. Oleh karena itu,
penulis mengharapkan saran dan kritik dari para pembaca yang bersifat
membangun demi kesempurnaan dari makalah ini. Penulis berharap makalah ini
dapat bermanfaat bagi pembaca pada umumnya terutama bagi dunia kedokteran
hewan di Indonesia.
Denpasar, 9 September 2019
Penulis
iv
DAFTAR ISI
HALAMAN SAMPUL ......................................................................................... i
RINGKASAN/SUMMARY ................................................................................. ii
KATA PENGANTAR ........................................................................................ iv
DAFTAR ISI ....................................................................................................... v
DAFTAR GAMBAR ......................................................................................... vii
DAFTAR LAMPIRAN ..................................................................................... viii
BAB I PENDAHULUAN .................................................................................... 1
1.1 Latar Belakang .......................................................................................... 1
1.2 Rumusan Masalah ..................................................................................... 2
BAB II TUJUAN DAN MANFAAT PENULISAN ............................................. 3
2.1 Tujuan Penulisan ....................................................................................... 3
2.2 Manfaat Penulisan ..................................................................................... 3
BAB III TINJAUAN PUSTAKA ......................................................................... 4
3.1 Pengertian Trepanasio ............................................................................... 4
3.2 Tujuan dan Manfaat Pembedahan Trepanasio ............................................ 5
BAB IV PEMBAHASAN .................................................................................... 6
4.1 Persiapan Pre-Operasi Trepanasio .............................................................. 6
4.2 Teknik Operasi Trepanasio ........................................................................ 7
4.3 Perawatan Pasca Operasi Trepanasio ....................................................... 13
v
BAB V SIMPULAN DAN SARAN ................................................................... 15
5.1 Simpulan ................................................................................................. 15
5.2 Saran ....................................................................................................... 15
DAFTAR PUSTAKA ........................................................................................ 17
LAMPIRAN ...................................................................................................... 18
vi
DAFTAR GAMBAR
Gambar 1. Alat trepan .......................................................................................... 4
Gambar 2. Situs trepanasi sinus frontal ................................................................ 7
Gambar 3. Situs trepanasi RMS dan CMS ............................................................ 8
Gambar 4. Situs trepanasi sinus ............................................................................ 8
Gambar 5. Trephine Galt dengan berbagai diameter ............................................. 9
Gambar 6. Trepanasi dan sinuskopi sinus frontal................................................ 10
Gambar 7. Pembuatan sayatan pada kulit dan periosteum ................................... 11
Gambar 8. Pembuatan lubang trepanasi .............................................................. 11
Gambar 9. Eksudat mengalir melalui lubang trepanasi ....................................... 12
Gambar 10. Penjahitan lubang trepanasi dan pemasang kateter Foley ................. 12
Gambar 11. Irigasi sinus pasca operasi trepanasi sinus ....................................... 13
vii
DAFTAR LAMPIRAN
Lampiran 1. Comparsion Between Three Techniques for Videosinuscopy in Cattle
Lampiran 2. Standing Equine Sinus Surgery
Lampiran 3. Surgery of The Sinuses and Eyes
Lampiran 4. Disorders of the Paranasal Sinuses
Lampiran 5. Diagnostic and Therapeutic Procedures for the Upper Respiratory
Tract
viii
BAB I
PENDAHULUAN
1.1 Latar Belakang
Trepanasio atau trepanasi adalah suatu tindakan operasi dengan membuka
suatu rongga yang berdinding keras dengan menggunakan alat trepan. Salah satu
contoh trepanasio adalah operasi craniotomy. Craniotomy adalah salah satu
tindakan operasi dengan membuka tulang kepala yang bertujuan mencapai otak
untuk tindakan pembedahan definitive dengan menggunakan alat trepan, misalnya
pada operasi sinus di daerah kepala atau operasi pada liang atau rongga sumsum
tulang.
Tulang kepala memiliki rongga yang sempit yang hanya cukup ditempati oleh
otak dan cairan peredam otak (cairan cerebrospinal), maka dari itu bila terjadi
pembengkakan akibat cedera kepala dapat menyebabkan peningkatan tekanan
dalam rongga kepala. Jika hal ini terus dibiarkan, maka akan menekan batang otak
sehingga fungsi-fungsi vital dalam tubuh seperti fungsi pernafasan, sirkulasi dan
kesadaran akan terganggu yang dapat menyebabkan kematian.
Jenis-jenis operasi trepanasio pada hewan dapat dibedakan berdasarkan
tempat atau daerah yang akan dilakukan proses pembukaan rongga tersebut.
Operasi trepanasio sering dilakukan pada hewan besar, antara lain untuk
membuka sinus maxillaris mayor, sinus maxillaris minor, sinus choncho frontalis,
sinus frontalis, rongga hidung dan rongga-rongga pada rahang bawah. Trepanasio
tidak hanya membuka suatu rongga yang dibatasi oleh tulang, melainkan dapat
juga untuk trepanasio jaringan lemak dibawah kulit misalnya pada kulit kelopak
mata bawah dengan tujuan operasi pengobatan entropion dan ectropion. Prosedur
dari pelaksanaan operasi trepanasio dapat bervariasi tergantung pada kondisi dari
hewan tersebut.
1
1.2 Rumusan Masalah
Adapun rumusan masalah yang didapatkan adalah sebagai berikut:
1. Apa yang dimaksud dengan teknik operasi trepanasio?
2. Apa saja tujuan dan manfaat dari teknik operasi trepanasio?
3. Bagaimana persiapan pre-operasi trepanasio?
4. Bagaimana teknik operasi trepanasio?
5. Bagaimana perawatan pasca operasi trepanasio?
2
BAB II
TUJUAN DAN MANFAAT PENULISAN
2.1 Tujuan Penulisan
Adapun tujuan dari penulisan ini, antara lain:
1. Untuk mengetahui definisi dari trepanasio
2. Untuk mengetahui tujuan dan manfaat dari operasi trepanasio
3. Untuk mengetahui pre-operasi, teknik operasi, dan perawatan pasca
operasi trepanasio
2.2 Manfaat Penulisan
Manfaat penulisan yang didapat diantaranya adalah untuk menambah
wawasan tentang pembedahan terutama bedah pada bagian cranial berupa teknik
operasi trepanasio pada hewan kecil dan besar. Selain itu, manfaat lain yang
didapatkan adalah untuk memberikan informasi baru tentang perkembangan ilmu
bedah yang mungkin belum didapatkan pada bangku perkuliahan.
3
BAB III
TINJAUAN PUSTAKA
3.1 Pengertian Trepanasio
Trepanasio atau trepanasi adalah operasi membuka suatu rongga yang
berdinding keras, misalnya tulang dengan menggunakan alat trepan. Misalnya
pada operasi sinus di daerah kepala atau operasi pada liang (rongga) sumsum
tulang. Trepanasi sering dilakukan pada hewan besar, antara lain untuk membuka
sinus maxillaris mayor, sinus choncho frontalis, sinus frontalis, rongga hidung,
dan rongga- rongga pada rahang bawah (Sudisma et al., 2006).
a
b
.
Gambar 1. Alat Trepan (a) Michele Trepan (b) Galt Trepan (Schleining, 2016).
Trepanasi dapat dilakukan menggunakan alat trepan Galt atau trepan Michele.
Keuntungan dari trepan Galt adalah menghasilkan portal akses yang lebih besar ke
daerah sinus (Schleining, 2016).
Akses ke sinus dilakukan dengan teknik trepaning, pertama dengan bor,
membuat pembukaan tengkorak kecil, kemudian diperkuat oleh gerakan rotasi
dengan trepan melingkar 20 mm. Lokasi trepanasi yang dipilih didasarkan pada
anatomi spesies dan difasilitasi oleh visualisasi tulang yang bertujuan untuk
evaluasi bilateral sinus frontal, maxilla dan palatina (Basso et al., 2016)
Trepanasi tidak hanya untuk membuka suatu rongga yang dibatasi oleh
tulang, melainkan dapat juga untuk trepanasi jaringan lemak di bawah kulit,
4
misalnya pada kulit kelopak mata bawah dengan tujuan operasi pengobatan
entropion dan ectropion (Sudisma et al., 2006).
3.2 Tujuan dan Manfaat Pembedahan Trepanasio
3.2.1 Trepanasi Sinus Maxillaris Minor
Trepanasi sinus maxillaris minor biasanya dilakukan untuk tujuan: 1.
Pengobatan emphyema, neoplasma dan tumor pada sinus maxillaris minor;
2. Membantu dalam usaha pencabutan gigi molaris ke III dan IV pada kuda;
dan 3. Untuk tujuan operasi diagnostik.
3.2.2 Trepanasi Sinus Maxillaris Mayor
Trepanasi sinus maxillaris mayor biasanya dilakukan untuk tujuan: 1.
Pengobatan emphyema, neoplasma dan tumor pada sinus maxillaris mayor;
2. Membantu dalam usaha pencabutan gigi molaris VI pada kuda; dan 3.
Untuk tujuan operasi diagnostik.
3.2.3 Trepanasi Sinus Choncho Frontalis
Trepanasi sinus choncho frontalis biasanya dilakukan untuk mencapai
sinus maxillaris minor dan mayor sekaligus dari satu lubang.
3.2.4 Trepanasi Sinus Frontalis
Trepanasi sinus frontalis biasanya dilakukan untuk indikasi: 1.
Pengobatan emphyema, neoplasma sinus frontalis; 2. Untuk tujuan operasi
diagnostic percobaan; dan 3. Pertolongan pada suatu keadaan depresi
dimana terjadi infraksio os frontalis (os frontalis melekuk ke dalam)
(Sudisma et al., 2006).
5
BAB IV
PEMBAHASAN
4.1 Persiapan Pre-Operasi Trepanasio
Sebelum dilakukan teknik operasi trepanasio dilakukan persiapan operasi,
seperti persiapan alat, obat, hewan, dan tempat operasi. Alat-alat yang digunakan
harus steril, obat yang disiapkan dapat berupa preanastesi, anastesi, antiradang,
antibiotik, dan disinfektan. Persiapan hewan sebelum dilakukan operasi dalam hal
ini yaitu pemeriksaan fisik hewan.
Apabila yang sakit sebelah kiri maka hewan dibaringkan ke sebelah kanan
atau dibaringkan ke bagian yang sehat. Selanjutnya rambut di tempat operasi
dibersihkan, didesinfeksi dan dianestesi lokal. Bila diperlukan dapat juga
dilakukan dengan anestesi umum (Sudisma et al.,, 2006).
Untuk standing surgery pada kuda, pasien harus berada dalam kandang jepit
serta direstrain menggunakan halter. Halter harus digunakan untuk menahan
kepala agar meminimalkan pergerakan selama prosedur pembedahan. Kulit di
bagian yang akan dilakukan trepanasio dijepit bagian pinggirnya minimal 2 cm
dari bagian yang akan dilakukan teknik trepanasio. Kemudian dilakukan scrub
atau didesinfeksi menggunakan chlorhexidine diikuti dengan alkohol. Pastikan
tidak menyentuh mata karena dapat menyebabkan keratitis kimiawi yang parah.
Kemudian diberikan premedikasi kombinasi
α2-agonis (romifidine atau
detomidine) ditambah butorphanol dan diberikan NSAID (seperti flunixin atau
phenylbuatzone) secara rutin (Barakzai dan Dixon, 2014). Kemudian anastesi
secara subkutan 1-2 mL larutan anastesi lokal (misalnya, 2% lidokain atau
mepivacaine) (Schleining, 2016).
6
4.2 Teknik Operasi Trepanasio
4.2.1 Trepanasi pada Sinus Kuda
A. Situs Trepanasi Sinus
Portal sinus frontal dapat digunakan untuk memeriksa lesi pada frontal,
conchal dorsal, maksilla kaudal, dan pintu masuk ke sinus etmoidal dan
sinusopalatin. Situs untuk portal ini diposisikan 0,5 cm kaudal dari garis
antara canthi medial kiri dan kanan, dan setengah jalan antara garis tengah
dan canthus medial ipsilateral. Portal ini sangat berguna untuk kuda muda
yang gigi pipinya menempati sebagian besar sinus maksilaris. Ini juga
menyediakan akses ke rostral maxillary sinus (RMS) dan VCS jika ventral
conchal bulla difenestrasi di bawah bimbingan endoskopi.
Gambar 2. Situs trepanasi sinus frontal (Barakzai dan Dixon, 2014).
Sinus maksilaris rostral (RMS) dan kaudal kuda muda (usia 6 tahun)
tidak boleh ditrepanasi secara rutin, karena berisiko merusak mahkota
cadangan gigi pipi. Jika trephinasi sinus maksilaris rostral harus dilakukan
pada kuda muda, panduan radiografi untuk memposisikan portal sangat
disarankan. Situs trepanasi RMS yang paling tepat pada dewasa kuda ialah
diposisikan 40% dari jarak antara ujung rostral krista facialis dan canthus
medial mata, dan 1 cm ventral dari garis yang menggabungkan foramen
infraorbital dan canthus medial. Portal sinus maksilaris kaudal (CMS)
7
merupakan lokasi yang berperan dalam sinoskopi CMS, sphenopalatine, dan
sinus conchofrontal. Situs ini diposisikan 2 cm rostral dan 2 cm ventral dari
canthus medial mata.
Gambar 3. Situs trepanasi sinus maksilaris rostral (RMS) dan sinus maksilaris
kaudal (CMS) (Barakzai dan Dixon, 2014).
Gambar 4. Situs trepanasi sinus (1) sinus maksilaris rostral (RMS), (2) sinus
maksilaris kaudal (CMS), dan (5) sinus frontalis (Tremaine dan Freeman, 2007).
B. Teknik Trepanasi Sinus
1. Kuda dibius secara rutin menggunakan α2-agonis dicampur dengan
butorphanol.
2. Kulit di situs trepanasi dipotong dan dipersiapkan secara aseptik.
3. Sebanyak 1 hingga 2 mL larutan anestesi lokal (misalnya, 2% lidokain
atau mepivacaine) diinfiltrasi secara subkutan.
8
4. Skalpel digunakan untuk membuat insisi tusukan menembus kulit dan
tulang (Woody, 2011). Sebuah sayatan linier 1,5 hingga 2,5 cm dibuat
di kulit dan periosteum di bawahnya, ukuran sayatan tergantung pada
ukuran trephine yang digunakan.
5. Melalui sayatan ini, tulang ditrepanasi menggunakan bor berdiameter
1,0 hingga 1,5 cm atau trephine Galt.
Gambar 5. Trephine Galt dengan berbagai diameter
6. Menggunakan retraktor penahan diri dapat mencegah kerusakan pada
kulit dan periosteum selama trepanasi. Harus diperhatikan bahwa
hanya sedikit panjang dari trephine yang dimasukkan ke dalam sinus
untuk menghindari kerusakan struktur intrasinus (khususnya tulang
ethmoid) dan menginduksi perdarahan intraoperatif.
7. Jika fenestrasi bula conchal ventral akan dilakukan, pembukaan
trepanasi berdiameter 8-10 mm dapat dilakukan segera di bawah situs
sebelumnya untuk memberikan ruang yang cukup untuk manipulasi
forceps/rongeurs dan ekstraksi bulla di bawah panduan endoskop.
8. Endoskop dimasukkan ke dalam sinus dan dilakukan sinoskopi.
Sebuah lavage tube atau kateter Foley kemudian dapat ditempatkan di
sinus dan diamankan sebagaimana mestinya. Hal ini dilakukan untuk
mengaspirasi cairan sebagai sampel untuk kultur dan sitologi. Apabila
cairan bersifat kental, sinus dapat diirigasi dengan 20-30 mL saline
steril hingga sampel didapatkan.
9. Setelah irigasi, insisi pada kulit dapat ditutup dengan staples atau
jahitan tunggal. Pilihan lain adalah dengan menempatkan kateter
menetap untuk irigasi di kemudian hari. Jika tabung in-dwelling tidak
9
dibiarkan di situ, sayatan mungkin tertutup seperti semula (Woody,
2011).
Gambar 6. (a) Trepanasi sinus frontal sedang dilakukan menggunakan bor (b)
Sinoskopi sinus frontal (Barakzai dan Dixon, 2014).
4.2.2 Trepanasi Sinus Kuda pada Kasus Empyema
Sinus empyema terjadi karena obstruksi drainase nasomaxillary dengan
dihasilkannya akumulasi mukus di sinus yang kemudian menjadi infeksi.
Beberapa kasus terjadi setelah infeksi pada saluran respirasi atas yang
menyebabkan peradangan, peningkatan mukus pada sinus, dan penurunan
sekresi dari sinus ke rongga hidung. Dalam melakukan trepanasi ini kuda
biasanya dianestesi umum atau berdiri. Dalam melakukan treatment ini tidak
selalu mengguanakan teknik trepanasi, namun juga dapat menggunkan
debridement atau sinonasal fistulation untuk drainase. Namun ada saat tertentu
harus menggunakan teknik trepanasi misalnya untuk menjangkau tempat
terjadinya lesi. Berikut merupakan penggambaran teknik dari trepanasi tersebut
(Tremaine dan Freeman, 2007).
1. Sebuah sayatan lengkung dibuat melalui kulit dan periosteum yang
kemudian akan ditarik menjauhi muka sehingga memungkinkan untuk
prosedur osteotomy tulang nasofrontal. Prosedur dilakukan dalam
keadaan kuda berdiri dan disedasi.
10
Gambar 7. Pembuatan sayatan pada kulit dan periosteum (Tremaine dan
Freeman, 2007).
2. Dibuat lubang trepanasi menggunakan alat trepine seluas 5 cm yang
bertujuan untuk membuat flap tulang besar ke dalam sinus frontalis kuda,
memungkinkan akses bedah untuk sinus dorsal conchal, frontal dan
caudal maksila. Potongan tulang dari trepanasi dibuang.
Gambar 8. Pembuatan lubang trepanasi (Tremaine dan Freeman, 2007).
3. Setelah dibuat lubang, eksudat purulen berlebih mengalir dari tulang
nasofrontal pada kasus kronis sinus empyema.
11
Gambar 9. Eksudat mengalir melalui lubang trepanasi (Tremaine dan Freeman,
2007).
4. Lipatan kulit dan periosteum digunakan untuk menutupi lubang yang ada
di os frontal. Dengan menggunakan jahitan terputus (seperti ditunjukkan
oleh
tanda
panah).
Telah
dilakukan
juga
trepanasi
maksila
memungkinkan irigasi post-pembedahan untuk sinus maxillaris melalui
kateter Foley.
Gambar 10. Penjahitan lubang trepanasi dan pemasang kateter Foley (Tremaine
dan Freeman, 2007).
12
4.3 Perawatan Pasca Operasi Trepanasio
Setelah pembedahan, kulit dapat dijahit atau dibiarkan untuk bergranulasi
dengan sendirinya apabila terkontaminasi kronis. Situs trepanasi dapat dibiarkan
dahulu terbuka untuk sembuh dengan sendirinya. Namun situs trepanasi perlu
ditutup untuk menghalangi masuknya debu dan kontaminan lain ke dalam sinus.
Perban stent menggunakan caprolactam terpolimerisasi # 2 (atau bahan jahitan
yang tidak dapat diserap lainnya) dengan mudah dibuat dengan menempatkan 2
jahitan terputus regang melalui kulit tegak lurus ke lokasi bedah, satu di atas dan
satu di bawah sayatan. Segmen umbilical tape 12 inci harus melewati setiap
jahitan. Gulungan spons kasa 4x4 atau kasa gulung 4 inci kemudian dapat
ditempatkan di atas sayatan dan diamankan di tempatnya oleh umbilical tape.
Perban kemudian dapat dilepas dan diganti untuk prosedur sinus lavage
berikutnya atau sebagai alternatif dibiarkan sampai sinusotomi telah dikaburkan
oleh jaringan granulasi (Schleining, 2016).
Perawatan pasca operasi trepanasi tergolong minim. Situs trepanasi perlu
dimonitor akan adanya perkembangan selulitis (Woody, 2011). Perawatan pasca
operasi juga sebaiknya mencakup penggunaan obat anti radang seperti meloxicam
per oral atau flunixin meglumine secara intravena (Schleining, 2016). Mukosa
sinus sangat peka dan hanya larutan antiseptik yang sangat encer yang harus
digunakan untuk membersihkan sinus. Larutan yang mengandung sabun tidak
boleh digunakan untuk irigasi sinus. Tujuan utama irigasi sinus adalah untuk
secara fisik mengeluarkan dan melarutkan materi dalam sinus, daripada
memberikan reaksi antibakteri. Irigasi karenanya harus dilakukan 2 hingga 3 kali
sehari dengan volume yang besar (3-5 L). Larutan irigasi yang dapat digunakan
ialah povidone iodine 0,05%, saline steril (0,9% sodium klorida), saline isotonis
(9 g gram dilarutkan dalam 1 L air), dan air keran. (Barakzai dan Dixon, 2014).
13
Gambar 11. Irigasi sinus pasca operasi trepanasi sinus menggunakan larutan
saline (Barakzai dan Dixon, 2014).
14
BAB V
SIMPULAN DAN SARAN
5.1 Simpulan
Trepanasio atau trepanasi adalah operasi membuka suatu rongga yang
berdinding keras, misalnya tulang dengan menggunakan alat trepan. Misalnya
pada operasi sinus di daerah kepala atau operasi pada liang (rongga) sumsum
tulang. Trepanasi sinus dilakukan untuk tujuan pengobatan emphyema, neoplasma
dan tumor pada sinus; membantu dalam usaha pencabutan gigi pada kuda; serta
untuk tujuan operasi diagnostik.
Persiapan bedah trepanasi mencakup merestrain pasien dalam kandang jepit
serta menggunakan halter. Kulit di bagian yang akan dilakukan trepanasio dijepit
pinggirnya. Kemudian dilakukan scrub atau didesinfeksi dan pasien diberikan
premedikasi kombinasi α2-agonis ditambah butorphanol dan diberikan NSAID
(seperti flunixin atau phenylbuatzone) secara rutin (Barakzai dan Dixon, 2014).
Kemudian anastesi secara subkutan 1-2 ml larutan anastesi lokal (Schleining,
2016).
Teknik prosedur operasi trepanasi mencakup melakukan insisi sedalam kulit
dan tulang dengan lebar sayatan disesuaikan ukuran threpine. Kemudian melalui
sayatan, tulang ditrepanasi oleh bor atau trephine Galt. Endoskop pun dimasukkan
ke dalam sinus untuk kepentingan sinoskopi. Sebuah lavage tube atau kateter
Foley ditempatkan di sinus untuk mengaspirasi cairan. Insisi pada kulit dapat
ditutup dengan staples atau jahitan tunggal. Perawatan pasca operasi trepanasi
tergolong minim.
5.2 Saran
Situs trepanasi perlu dimonitor akan adanya perkembangan selulitis. Mukosa
sinus sangat peka dan hanya larutan antiseptik yang sangat encer yang harus
15
digunakan untuk membersihkan sinus. Larutan yang mengandung sabun tidak
boleh digunakan untuk irigasi sinus.
16
DAFTAR PUSTAKA
Basso, F. Z., E. M. Busato, J. R. da Silva, R. L. Guedes, I. R. B. Filho, dan P. T.
Dornbusch.
2016.
Comparsion
Between
Three
Techniques
for
Videosinuscopy in Cattle. Departemento de Medicina Veterinaria. Vol. 46
(7): 1262- 1267
Barakzai, S. Z., dan Padraic M. Dixon. 2014. Standing Equine Sinus Surgery.
Veterinary Clinics of North America: Equine Practice. Vol. 30(1) : 45–62.
Schleining, Jennifer A. 2016. Surgery of The Sinuses and Eyes. Veterinary Clinics
of North America : Food Animal Practice. Vol. 32 : 571-591.
Sudisma et al.,, I. G. N., I.G.A.G.P. Pemayun., A.A.G.J. Wardhita., I.W. Gorda.
2006. Ilmu Bedah Veteriner dan Teknik Operasi. Denpasar: Pelawa Sari.
Tremaine, Henry dan David E. Freeman. 2007. Disorders of the Paranasal
Sinuses. Equine Respiratory Medicine and Surgery. DOI: 10.1016/B978-07020-2759-8.50031-3,
Woodie, J. Brett. 2011. Diagnostic and Therapeutic Procedures for the Upper
Respiratory Tract. American Association of Equine Practitioners
Proceedings. Vol. 57 : 5-7.
17
LAMPIRAN
18
http://dx.doi.org/10.1590/0103-8478cr20141478
Ciência Rural, Santa Maria, v.46, n.7,Comparison
p.1262-1267,
jul, 2016
between
three techniques for videosinuscopy
in cattle.
1262
ISSN 1678-4596
CLINIC AND SURGERY
Comparison between three techniques for videosinuscopy in cattle
Comparação entre três técnicas para videosinuscopia em bovinos
Fernando Zanlorenzi BassoI Eduarda Maciel BusatoI Jéssica Rodrigues da SilvaI
Rogério Luizari GuedesII Ivan Roque de Barros FilhoIII Peterson Triches DornbuschIII
ABSTRACT
Cattle have extensive paranasal sinuses that are
susceptible to disease, most commonly sinusitis. The sinuscopy
can be used to evaluate these structures, although there are no
descriptions of this region for endoscopic anatomy, especially
regarding the trocar position and the most appropriate type
of endoscope. This study aimed to standardize the surgical
approaches to sinuscopy in cattle by comparing the use of
three endoscopes. Four accesses by trephination (one hole for
each of the maxillary and frontal sinuses) were made in eight
heads of slaughtered cattle. Each hole was inspected with three
endoscopes: a 10mm flexible colonoscope with up to 180º of
angulation, a 10mm 0° laparoscope and a 4mm 30º arthroscope.
It was observed that all regions of the maxillary sinus were better
visualized with the 4mm endoscope, and the structures of this
sinus were less well visualized with the 10mm laparoscope. The
frontal sinus was difficult to evaluate due to the tortuosity of its
bony projections, and the cranial portion was not observed by
the proposed accesses. The caudal regions of the frontal sinus
such as the nuchal diverticulum and the back of the orbit had the
greatest number of structures visualized by the 4mm endoscope,
followed by the colonoscope. The comparative analysis showed
that the 4mm endoscope was most efficient and could be adapted
to sinuscopy in cattle.
Key words: endoscopy, videosurgery, nasal sinus, sinusitis, bovine.
RESUMO
Os bovinos apresentam seios paranasais extensos e
passíveis de afecções, como a sinusite. A sinuscopia, técnica já
utilizada em outras espécies, avalia os seios paranasais de modo
pouco invasivo e não é descrita em bovinos. O presente estudo
objetivou padronizar os acessos cirúrgicos para sinuscopia
em bovinos, testando três técnicas de videoendoscopia.
Foram selecionadas oito cabeças de bovinos provenientes de
abatedouro comercial, sendo realizada a trepanação dos seios
maxilares e frontais de ambos os lados (um orifício por seio).
Cada seio foi inspecionado com três óticas: um colonoscópio
flexível com 10mm de diâmetro e até 180º de angulação, um
laparoscópio rígido de 10mm e 0º e um artroscópio rígido de
4mm e 30º. Na região caudal do seio maxilar, os alvéolos e
abertura maxilopalatina foram visualizadas com todas as
óticas. A região caudodorsomedial e rostral do seio maxilar
foram observadas com a ótica flexível e a rígida de 4mm, sendo
que apenas esta adentrou no seio palatino. O seio frontal é de
difícil visualização, devido à tortuosidade de suas projeções
ósseas e sua porção cranial não foi observada pelo acesso
proposto. A região caudal do seio frontal, o divertículo nucal
e a área caudal à órbita tiveram o maior número de estruturas
visualizadas com a ótica rígida de 4mm, seguida da flexível. A
análise comparativa demonstra que a técnica utilizando a ótica
rígida de 4mm permite a visualização de um maior número de
estruturas com maior detalhamento e é a que mais se adapta à
sinuscopia em bovinos.
Palavras-chave: endoscopia, videocirurgia, seios nasais,
sinusite, bovino.
INTRODUCTION
The sinuses in cattle have peculiar
characteristics, are underdeveloped in calves and
acquire their full size after several years (DYCE
et al., 2010). The frontal sinus presents rostral and
caudal compartments that extend to the cornual
processes. The maxillary sinuses are unique and
Programa de Residência Multiprofissional em Saúde, Universidade Federal do Paraná (UFPR), Curitiba, PR, Brasil.
Programa de Pós-graduação em Ciências Veterinárias, Universidade Federal do Paraná (UFPR), 80035-050, Curitiba, PR, Brasil. E-mail:
[email protected]. Corresponding author.
III
Departamento de Medicina Veterinária, Universidade Federal do Paraná (UFPR), Curitiba, PR, Brasil.
I
II
Received 10.06.14
Approved 01.15.16
Returned by the author 04.08.16
CR-2014-1478.R3
Ciência Rural, v.46, n.7, jul, 2016.
1263
Basso et al.
large, and enable communication with the palatine
sinuses. They must be accessed via the hard palate,
making the surgical approach quite difficult (SISSON
& GROSSMAN, 1998).
Among the pathologies of the sinuses,
an inflammatory process called sinusitis stands
out. In cattle, the leading cause of frontal sinusitis
is associated with dehorning, as about 2% of
surgically dehorned animals develop this disease
(FIORAVANTI et al., 1999; SILVA et al., 2008). It
can also be associated with respiratory infections,
trepanations or fractures with frontal sinus
exposure, cysts or nasal cancer (SMITH, 2006).
Surgery by unqualified surgeons, the presence of
foreign bodies and improper postoperative therapy
are also important etiologic factors in this species
(FIORAVANTI et al., 1996).
The diagnosis of sinusitis in cattle is
based on history and clinical examination findings
(DIRKSEN et al., 1993). In several species, in addition
to a general clinical examination, some diagnostic
methods can be used such as regional radiographs,
sinucentesis, surgical exploration (sinusotomy),
tomography and sinuscopy; the latter is performed
with rigid or flexible endoscopes (ALLISON, 1999;
EMSHOFF et al., 1999; SMITH, 2006).
Sinuscopy has been performed in humans
(BERTRAND & ROBILLARD, 1985; PETRUSON,
2004), horses (PERKINS et al., 2009a) and dogs
(JOHNSON, 2006), due to its practicality and lower
postoperative morbidity compared to conventional
exploration techniques (SILVA et al., 2009). In
horses, sinuscopy is widely used to properly inspect
the sinuses as well to collect samples and perform
biopsies on those sites. In this procedure, the animal
can be kept sedated in the quadrupedal position; sinus
access occurs through trepanation, which allows for
the introduction of endoscopes (PERKINS et al.,
2009a; O’LEARY & DIXON, 2011). Until now, there
have been no studies regarding sinuscopy in cattle,
in terms of systematically describing the endoscopic
anatomy of the region, the access portals and the most
appropriate type of lens.
This study aimed to compare the
effectiveness of three different endoscopes in
sinuscopic evaluation of the maxillary, palatine
and frontal sinuses of cattle in a postmortem study.
The experiment also aimed to standardize the
minimally invasive surgical access for sinuscopy in
this species and to improve anatomical knowledge
with an emphasis on the endoscopic anatomy of
those regions.
MATERIALS AND METHODS
Eight cattle heads were used, obtained from
commercial slaughterhouses in Curitiba and nearby
cities. The heads were received skinless, dehorned
and partially stripped. The access to the sinuses was
carried out by a trepanning technique, first with a
drill, making a small skull opening, then amplified by
rotational moves with a 20mm circular trephine. The
chosen sites for trepanation were based on the species
anatomy and facilitated by bone visualization, aiming
for a bilateral evaluation of the frontal, maxillary and
palatine sinuses. The access holes for the maxillary
sinuses were located 3.7±0.9cm rostral to the eyeball
and 2.1±0.3cm dorsal to the facial crest (Figure 1A).
The access holes for the frontal sinuses were located
4.9±1.6cm rostral to the nuchal ridge and 2.8±0.5cm
lateral to the midline (Figure 2A).
The equipment used for cavity inspection
included a flexible colonoscope with a diameter of
10mm and angles up to 180° (Karl Storz, Germany), a
10mm and 0° laparoscope (Karl Storz, Germany), and
a 4mm and 30° arthroscope (Karl Storz, Germany);
all were coupled to a laparoscopic unit composed by
a LED monitor, a microcam and a xenon light source
(Telepack®, Karl Storz, Germany). The sinuses were
inspected with the three endoscopes, trying to identify
Figure 1 - Illustration of the sinuses in a bovine head in a left
lateral view. A: access hole to the maxillary sinus;
B: caudal and caudo-dorsomedial areas from
maxillary sinus; C: maxilo-palatine opening; D:
dental alveoli. Adapted from BUDRAS & HABEL,
2003.
Ciência Rural, v.46, n.7, jul, 2016.
Comparison between three techniques for videosinuscopy in cattle.
Figure 2 - Illustration of the sinuses in a bovine head (cranial
view). A: access hole to the frontal sinus; B:
nuchal diverticulum; C: frontal sinus caudal
area; D: caudal area to the eyeball. Adapted from
BUDRAS & HABEL, 2003.
the highest number of structures possible, according
to the literature and the local anatomy of this species,
being classified as 1: visible or 2: not visible. All
inspections were documented individually for further
assessment, recording and the identified structures
were tabulated. Three independant evaluators were
selected, one with experience in videoendoscopic/
videolaparoscopic procedures in another species, and
the other two with knowledge of cattle anatomy. The
efficiency of these endoscopes was verified through
their viewing capability and identification of structures
by the surgeon evaluator. The group findings were
statistically compared by the non-parametric KruskalWallis test, followed by Dunn’s multiple comparison,
using Graphpad Prism software, V5.
RESULTS AND DISCUSSION
The literature concerning cattle sinuscopy
is rare, making it difficult to compare the literature with
the data obtained in this study. In horses, sinuscopy is
a tool used for the diagnosis, treatment and evaluation
of sinusitis (PERKINS et al., 2009b; DIXON et al.,
2012.). Besides horses, there are reports of sinuscopy
in dogs, but it is difficult to draw interrelationships
between studies of these species with cattle because
they have anatomically different paranasal sinuses
(PETRUSON, 2004; JOHNSON, 2006).
1264
During this study, a 20mm diameter circular
trephine was used, but smaller diameters such as 14 or
15mm may be used for the same purpose (PERKINS
et al., 2009b). MACHADO & SILVA (2013) carried
out an 8mm trepanation to compare rigid and a flexible
sinuscopy in horses, using a 4mm 30° rigid endoscope
and a flexible endoscope 4.8mm in diameter. Due the
10mm endoscope used in the present study, it was not
possible to work with smaller trephines.
The trephination areas and sinuses were
selected based on anatomy, but they may be modified
according to the purposes of the exam (SMITH,
2006). The main identified areas are displayed in
figure 3. Through the frontal sinus access, a caudal
observation was made of this region, the nuchal
diverticulum, the caudal region of the eyeball, but the
exploration was complicated by the presence of large
numbers of intrasinusal lamellae (Figure 3C).
Data in percentages referring to viewing
capacity from different areas and techniques are
compiled on table 1. The visualization of the caudal
frontal sinus area (Figure 2C) varied according to
the equipment used; the 4mm 30° arthroscope was
most efficient (viewing rate of 87.5%). It was not
possible to see the desired structure in only one of
the eight heads, bilaterally, due the greater presence
of bone irregularities therein. The colonoscope with
a diameter of 10mm and angles up to 180° ranked
second, with 62.5% successful visualizations, while
the 10mm 0° endoscope had the lowest viewing rate
among all tested endoscopes, as it was effective in
less than half of the heads (43.75%). Observation
of the nuchal diverticulum was possible only with
the arthroscope and colonoscope, in 81.25% and
12.50% of accesses, respectively (Figure 2B). During
the experiment, the caudal area to the eyeball was
visualized by some accesses with the arthroscope
(56.25%) and colonoscope (25%). The laparoscope
proved to be ineffective for this purpose.
The rostral region of the frontal sinus
presents a tortuous anatomy, marked by intrasinusal
lamellae, resulting in irregular areas (BUDRAS &
HABEL, 2003; DYCE et al., 2010), which prevent
the insertion of endoscopes through the proposed
access. The cornual processes were not visible
because the heads were obtained from previously
dehorned animals.
Inspection of the maxillary sinuses was
easier and didactic when compared with the frontal
sinuses, because the maxillae have a small number
of tortuous bones and a more regular anatomy. This
finding is in counterpoint to the purpose of the
examination, since the major diseases of the bovine
Ciência Rural, v.46, n.7, jul, 2016.
1265
Basso et al.
Figure 3 - Explored anatomical areas identified during the video sinuscopy in cattle. A: dental alveolus; B:
maxilo-palatine opening; C: tortuosity from frontal sinus; D: maxillary sinus, caudo-dorsomedial
portion; E: palatine sinus; F: maxillary sinus, caudal portion; G: maxillary sinus, rostral portion; H:
palatine sinus.
paranasal sinuses are associated with dehorning,
and therefore good visualization of the frontal sinus
would be interesting (SILVA et al., 2008).
The caudal area of the maxillary sinuses
achieved excellent viewing with all endoscopes
used (Figure 1B; Figure 3F). The caudodorsomedial
portion of the same area (Figure 1B; Figure 3D) had
slightly limited inspection when the laparoscope was
used, because it was ineffective in three of the 16
views. The dental alveoli (Figure 1D; Figure 3A)
and the maxillopalatine opening (Figure 1C; Figure
3C) were readily observed with all three endoscopes
(viewing rate of 100%); however, the palatine sinus
(Figure 3E; Figure 3H) could not be accessed in all
heads. The most effective endoscopic access to the
palatine sinus was achieved with the arthroscope,
which attained a 93.75% viewing rate, with only
one not evaluated due a narrower maxillopalatine
opening than the others. The other endoscopes
showed poor efficiency to this area, with a viewing
rate of 25% with the colonoscope and a 6.25% with
the laparoscope. The rostral region of the maxillary
sinus (Figure 3G) was inspected with 100% efficiency
when using the arthroscope and 87.5% efficiency
with the colonoscope; however, this viewing area
was not accessible with the laparoscope.
Ciência Rural, v.46, n.7, jul, 2016.
Comparison between three techniques for videosinuscopy in cattle.
1266
Table 1 - View capacity (percentage and total number of animals) of the anatomical regions from paranasal sinuses in the evaluated cattle
heads during the video-endoscopy techniques (n=16).
Viewed area
Rigid optic 4mm e 30°
Frontal sinus (rostral portion)
Frontal sinus (caudal portion)
Nuchal diverticulum
Eyeball (caudal portion)
Maxilar sinus (rostral portion)
Maxilar sinus (caudal portion)
Maxilar sinus (caudo-dorsomedial portion)
Palatine sinus
Maxilo-palatine opening
Dental alveoli
0% (0)a
87.5% (14)a
81.3% (13)a
56.3% (9)a
100% (16)a
100% (16)a
100% (16)a
93.8% (15)a
100% (16)a
100% (16)a
Flexible optic 10mm e 180°
0% (0)a
62.5% (10)ab
12.5% (2)b
25% (4)ab
87.5% (14)a
100% (16)a
100% (16)a
25% (4)b
100% (16)a
100% (16)a
Rigid optic 10mm e 0°
0% (0)a
43.8% (7)b
0% (0)b
0% (0)b
0% (0)b
100% (16)a
81.3% (13)a
6.3% (1)b
100% (16)a
100% (16)a
ab
Values with different superscripts in the same row are statistically different according to the Kruskal-Wallis test (P<0.05), followed by the
Dunn`s multiple comparison test (P<0.05), using the software Graphpad Prism, V5.
CONCLUSION
DIRKSEN, G. Sistema digestivo. In: ROSENBERGER. Exame clínico
dos bovinos. Rio de Janeiro RJ: Guanabara Koogan, 1993. p.166-228.
A comparative analysis of the effectiveness
of different endoscopes shows that a rigid endoscope
with 4mm and 30° is the most adaptable for cattle
sinuscopy, because it has a smaller diameter and a
higher angulation view, which are required to access
structures with a narrow opening, such as the palatine
sinus. Although, more accesses sites need to be tested,
trying to optimize the viewing of the other endoscopes
used in this study. The maxillary and palatine sinus
anatomies are more regular than the frontal sinuses,
which facilitates sinuscopic inspection of the first
ones. The proposed accesses to maxillary and palatine
sinuses are adequate, while the techniques for frontal
sinus have limitations in the rostral sinus views.
BIOETHICS
AND
COMMITTEE APPROVAL
BIOSSECURITY
This study was submitted to the Ethics Committee
for animal use of the Agricultural sciences sector (Universidade
Federal do Paraná (UFPR), Brazil), following the ethical principles
of the Brazilian College of Animal Experimentation (COBEA),
judged and approved under the process number 101/2010.
CONFLICT OF INTERESTS
There is no conflict of interests.
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Ciência Rural, v.46, n.7, jul, 2016.
Standing Equine Sinus Surgery
Safia Z. Barakzai, BVSc, MSc, DESTS, MRCVSa,*,
Padraic M. Dixon, MVB, PhD, MRCVSb
KEYWORDS
Horse Sinusitis Surgery Osteotomy Trephination
KEY POINTS
Trephination of the equine sinuses is a common surgical procedure in sedated standing
horses.
Standing sinus flap surgery has become increasingly popular and offers several advantages over sinusotomy performed under general anesthesia, including reduced patientassociated risks and costs and less intraoperative hemorrhage.
Other minimally invasive surgical procedures for managing equine sinusitis include
sinoscopic surgery, balloon sinuplasty, and transnasal laser sinonasal fenestration.
Regardless of the procedure used, appropriate indications for surgery, good patient selection, and familiarity with regional anatomy and surgical techniques are imperative to obtaining good results.
INDICATIONS FOR STANDING SINUS SURGERY
Standing sinus surgery is indicated in the horse to treat primary or secondary sinusitis
(Tables 1 and 2). Sinus surgery is also performed for diagnostic reasons, such as to
facilitate sinoscopy (direct sinus endoscopy), allow endoscopic-guided biopsy, or to
collect samples of the sinus contents for bacterial or fungal culture or histology. Standing sinus surgeries can be divided into sinus trephination procedures and sinus flap
surgery (osteoplastic flaps). Before performing either procedure, one must complete
a detailed case investigation to confirm the presence of sinusitis, collect as much
information as possible regarding the likely cause of the condition, determine which
sinus compartments are involved, and establish the positioning of the most appropriate surgical site. Indications for sinus surgery are therefore based on the results
of clinical examination, nasal endoscopy, skull radiography, and a detailed intraoral
examination. If available, adjunctive advanced imaging techniques such as
Disclosures: The authors have no conflict of interests.
a
Chine House Veterinary Hospital, Sileby, Leicestershire LE12 7RS, UK; b Dick Vet Equine
Hospital, Easter Bush Vet Centre, University of Edinburgh, Roslin, Midlothian EH25 9RG, UK
* Corresponding author.
E-mail address: [email protected]
Vet Clin Equine 30 (2014) 45–62
http://dx.doi.org/10.1016/j.cveq.2013.11.004
vetequine.theclinics.com
0749-0739/14/$ – see front matter Ó 2014 Elsevier Inc. All rights reserved.
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Table 1
Indications and contraindications for sinus trephination and standing sinus flap surgery
Indications
Contraindications
Sinus trephination
1. Sinoscopy
2. Placement of a lavage tube
3. Endoscopic fenestration of the
ventral conchal bulla10,16
4. Sinoscopically guided sinus
surgery (eg, for mass biopsy,
removal of inspissated pus,
conchal bone sequestrae, small
sinus cysts, fungal plaques,
formalin injection, or removal
of small intrasinus progressive
ethmoidal hematoma)
1. Bone opacity mass immediately
beneath the proposed trephine
site
Standing sinus
flap surgery
1. Primary sinusitis unresponsive to
or recurrent after conservative
management (antibiotics, sinus
trephination, and lavage)
2. Intrasinus mass diagnosed
preoperatively (eg, sinus cyst,
ethmoidal hematoma,
neoplasm)
3. Inspissated pus present within
the sinus (diagnosed with
radiography and/or sinoscopy);
cases can sometimes be
treated sinoscopically using
transendoscopic biopsy forceps
or wire retrieval baskets
4. Sinonasal fistulation, occasionally
indicated in cases of chronic
sinusitis with obstruction of the
nasomaxillary ostium; however,
effective removal of the primary
lesion from all compartments
will usually reduce mucosal
inflammation in these cases and
allow normal drainage within a
few days postoperatively (see
section on minimally invasive
techniques)
5. Depressed maxillary or frontal
bone fractures, which require
elevation and fixation or small
fragments that need to be
removed
1. Unsuitable patient temperament, particularly if sinonasal
fenestration is likely to be
required
2. Bone opacity intrasinus masses
detected radiographically (eg,
odontogenic tumors, osteoma);
these are likely to require
aggressive sectioning using
chisels or bone saws to enable
their removal, and this is often
not well tolerated in sedated
horses
3. Extraction of cheek teeth
through repulsion, unless oral
extraction has already been
attempted with significant
breakdown of the periodontal
ligament; repulsion of firmly
attached teeth is not tolerated
in the standing horse and
should not be attempted
scintigraphy, computed tomography (CT), or magnetic resonance imaging (MRI) may
be indicated before surgical procedures are performed.
Endoscopy Per Nasum
The tortuous, slit-like nature of the nasomaxillary aperture in normal horses prevents
direct examination of the paranasal sinuses using endoscopy per nasum. However,
nasal endoscopy is required to confirm that the sinuses are the source of nasal
discharge, and thereby rule out other causes of unilateral nasal discharge, such as
Standing Equine Sinus Surgery
Table 2
Comparisons between sinus flap surgery performed standing or under general anesthesia
Form of Restraint for
Sinus Surgery
Advantages
Disadvantages
Sedation in standing
horse
No risk or cost associated with
general anesthesia
Surgical theater/induction box
facilities not required
Less hemorrhage than when
surgery is performed under
general anesthesia, resulting in
improved visualization and
allows surgeons to take their
time
Unsuitable for some fractious
patients
Unsuitable if invasive or
aggressive interventions are
likely to be required
Reduction in sterility of
procedure (but usually a
contaminated/dirty
procedure anyway)
General anesthesia
Patient is immobilized and
nonresponsive during surgical
interventions
Suitable for fractious patients
Concurrent dental repulsion
can be performed
Small risk of mortality or
morbidity associated with
general anesthetic
Cost of general anesthesia
Requires facilities such as
surgical theater suite, operating table,
and recovery box
Volume of hemorrhage is
usually greater
disorders of the nasal cavity and guttural pouches, or lower respiratory tract infection/
inflammation, which can occasionally present as a unilateral nasal discharge.
A diagnosis of sinusitis is confirmed by recognition of mucopurulent or purulent material or blood emanating from the sinonasal ostium (sinus drainage angle), which is
situated at the caudal aspect of the middle meatus. Because of the narrow, complicated drainage pathway of the ventral conchal sinus (VCS), swelling of the ventral
nasal concha caused by accumulation of exudate within the VCS is common, and
often causes narrowing of the common and middle meati (Fig. 1). If severe, distension
of the VCS may also narrow the ventral meatus, and occasionally can completely
occlude the ipsilateral nasal cavity and displace the nasal septum toward the contralateral side. These horses will often have respiratory stridor at rest or exercise, and
careful assessment of nasal airflow may detect a reduction or absence of expired
air from the affected nostril. Remodeling of the nasal conchae is also common in horses with sinusitis (Fig. 2), and should not be confused with primary nasal lesions.
All horses with suspected sinusitis should undergo careful endoscopic examination
of the middle meatus on the affected side, because some horses with sinus disease,
including more than 20% with chronic primary sinusitis, will have a fistula from the
middle meatus into their VCS (see Fig. 2; Fig. 3) and less commonly into their dorsal
conchal sinus (DCS).1 If present, a small-diameter endoscope can often be passed
through this fistula into the VCS, and occasionally inspissated material or conchal
sequestrae can be removed from this compartment, thus allowing the sinusitis to be
treated endoscopically. Additionally, some horses have pieces of necrotic ventral
conchal bone (Fig. 4) lodged in the caudal aspect of the middle meatus, often surrounded by inspissated pus (which can be the cause of the persistent unilateral nasal
discharge), and this material can usually be removed transendoscopically. Horses that
have previously undergone sinus surgery with sinonasal fenestration to improve sinus
drainage will have a surgically created fistula.
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Fig. 1. Complete obstruction of the middle nasal meatus in a horse with sinusitis.
Radiography
Radiography is a well-established method of investigating sinus and dental disorders
in the horse. However, the complex 3-dimensional structure of the head means that
interpretation of radiographs in this region can be difficult in some cases. A minimum
of 3 radiographic views should be taken of horses with sinusitis: lateral, lateral oblique
(to examine individual cheek apices), and a dorsoventral view, the latter is taken specifically to establish if there is VCS involvement.2
Radiographs should be examined for the presence of abnormalities, such as
fluid lines, intrasinus soft tissue opacity, periapical dental infection, intrasinus
neoplasia, skull trauma, and distention of the VCS. Radiographs should also be
Fig. 2. Chronic destruction and remodeling of the dorsal concha in a horse with chronic
sinusitis. Note the large naturally occuring sinonasal fistula (arrows).
Standing Equine Sinus Surgery
Fig. 3. Naturally occurring sinonasal fistula into the VCS in a horse with chronic sinusitis.
used to determine which sinus compartments are affected. The use of digital and
computed radiography has increased in equine practice over the past few years
and has helped provide higher-quality images, increasing the sensitivity and specificity of sinus radiography.
Computed Tomography
Cross-sectional imaging methods such as CT (Figs. 5 and 6) and MRI are extremely
useful for evaluating the complex 3-dimensional structures of the equine head. The
availability of CT facilities that can image the head of standing horses is increasing
fast, making CT accessible to a larger number of horses. The advantages of CT
over conventional radiography in horses with sinusitis include accurate identification
of the sinus compartments involved, more precise identification of dental infection,3
Fig. 4. Bone sequestrum in the caudal aspect of middle meatus, causing chronic clinical
signs.
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Fig. 5. Standing sedated horse undergoing a CT scan of its head.
Fig. 6. Transverse CT image of a horse with dental sinusitis. Image shows a lateral “slab”
fracture of 209 (yellow arrow), gas attenuation within the common pulp chamber, and
gas around a lateral root of this tooth (white arrow), which confirms the diagnosis of apical
infection. Disruption of the dental alveolus is also present, and soft tissue attenuating material fills the rostral maxillary and ventral conchal sinuses. The dorsal nasal concha is also
filled with soft tissue–attenuating material and there is soft tissue swelling overlying the
maxillary bone.
Standing Equine Sinus Surgery
more information about the nature of sinus contents, and accurate identification
of other sinonasal abnormalities that are not visible on radiographs (eg, mucosal thickening, conchal necrosis, remodeling).3–5 In almost all cases, CT scans provide
additional information that is not provided by radiography and, in the authors’ experience, this extra information influences the subsequent treatment in most cases.
Oral Examination
The importance of a thorough oral examination in cases of sinusitis cannot be emphasized strongly enough. At least 41% of cheek teeth with periapical infections are now
known to have occlusal pulpar exposure6; therefore, finding pulpar exposure in a suspect tooth on oral examination may help greatly in definitively diagnosing dental sinusitis. The teeth should be examined (preferably in the sedated horse) with a full mouth
speculum in place, a strong headlamp, dental mirror or oral endoscope, and a dental
pick, which is used to probe the pulp cavities. The most obvious clinical sign to note is
packing of the pulp cavity with food material (Fig. 7). The dental pick should not
normally be able to enter the occlusal aspect of the pulp cavity, which should be filled
with secondary dentine. However, negative findings on oral examination do not
preclude the presence of apical infection, and occasionally pulpar exposure is found
in horses (particularly in older horses) without clinical signs of periapical infection.
In older horses with sinusitis, the junction of the hard palate and the maxillary cheek
teeth should be carefully inspected for the presence of red, proliferative soft tissue that
resembles granulation tissue. If present, this will usually be a squamous cell carcinoma
that may invade the nasal cavity or sinuses after neoplastic squames migrate from
their origin in the oral cavity up the periodontal spaces into the sinuses (Fig. 8). Biopsy
results of this abnormal oral tissue in combination with radiography will allow a definitive diagnosis, and help avoid more-invasive sinus surgery.
PREOPERATIVE PREPARATION
Performing endoscopy and radiography should provide the clinician with a good
idea of the horse’s temperament and suitability for standing sinus surgery. Horses
should be restrained in stocks for standing sinus surgery, and heavily sedated with
Fig. 7. (A) A dental probe is used to check for pulpar exposure. This 106 has multiple
exposed pulps into which the probe tip can be passed. (B) Extracted maxillary cheek tooth
with pulpar exposure of all 5 pulp horns (red arrows). Both infundibulae (yellow arrows)
also have occlusal cemental defects, as is present in 90% of all cheek teeth.
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Fig. 8. (A) The oral cavity of a horse that presented with left-sided nasal discharge. The
large, pink soft tissue mass lying palatally and buccally to the caudal cheek teeth is a squamous cell carcinoma that has invaded the overlying paranasal sinuses. (B) A transverse section of the affected horse after euthanasia. This image shows very extensive invasion of the
sinonasal region by this aggressive oral tumor.
a combination of an a2-agonist (romifidine or detomidine) plus butorphanol. Premedication with broad-spectrum antibiotics (the authors routinely use a combination of
neomycin and procaine penicillin intramuscularly) and a nonsteroidal antiinflammatory drug (eg, flunixin or phenylbutazone) is routine. A dental headstand is
useful for resting the horse’s head and keeping it steady during surgery (Fig. 9). The
surgeon should have a good head torch.
For sinus trephination, injecting 2 mL of local anesthetic at the proposed trephination site provides adequate analgesia. For standing sinusotomy, local infiltration of
skin along the incision sites on the maxilla or frontal bone is required, but a maxillary
Fig. 9. Horse sedated and prepared for standing sinus surgery, restrained in stocks and head
resting on a dental headstand.
Standing Equine Sinus Surgery
nerve block7,8 can also be useful for anesthetizing the sinus and nasal mucosa. Additionally, if fenestration into the nasal cavity is anticipated, endoscopically guided
topical anesthesia of the nasal mucosa preoperatively greatly increases patient
compliance when fenestrating and packing the nasal cavity. Once any degree of
hemorrhage into the nasal cavity occurs, topically anesthetizing the nasal mucosa becomes very difficult.
If both nasal cavities are significantly obstructed (usually because of a unilateral
lesion that is pushing the nasal septum across to the contralateral side), placing a
nasopharyngeal tube via the contralateral nasal cavity is useful to maintain a patent
airway during surgery and in the immediate postoperative period. In cases with severe
bilateral nasal obstruction, a temporary tracheostomy tube may be required.
SURGICAL TECHNIQUES
Sinus trephination is a technique that can be easily performed by most equine practitioners in the standing sedated patient. In contrast, sinus flap surgery is a procedure
that requires detailed anatomic knowledge and may be accompanied by complications such as significant intraoperative hemorrhage, damage to normal cheek teeth
alveoli or the infraorbital canal, postoperative wound infection, and recurrence of clinical signs. The presence of sinus distension and mucosal inflammation frequently distorts the normal sinus anatomy, making intraoperative decision making challenging.
For these reasons, sinus flap surgery should only be performed by veterinary surgeons
with training in and experience with the technique.
SINUS TREPHINATION
Trephination Sites
The frontal sinus portal is often the most useful, and can be used for examining lesions
in the frontal, dorsal conchal, caudal maxillary, and entrance to the ethmoidal and
sphenopalatine sinuses. The site for this portal is positioned 0.5 cm caudal to a line
drawn between the left and right medial canthi, and halfway between the midline
and the ipsilateral medial canthus (see Fig. 8). This portal is particularly useful in young
horses whose cheek teeth occupy much of the maxillary sinuses. It also provides
access to the rostral maxillary sinus (RMS) and VCS if the ventral conchal bulla is
fenestrated under endoscopic guidance.
The rostral and caudal maxillary sinuses of young horses (6 years of age) should
not be trephined routinely, because trephination risks damaging the reserve crowns
of the cheek teeth.9 Additionally, the long reserve crowns are located close to the
maxillary bone (the average distance from the maxilla to the lateral aspect of the cheek
teeth is 13 mm), which limits maneuverability of the endoscope within the sinus and
thus restricts visualization of the intrasinus structures. If trephination of the rostral
maxillary sinus must be performed in young horses, radiographic guidance for portal
positioning (lateral and dorsoventral views with markers in place) is strongly advised.
The caudal maxillary sinus (CMS) portal (for sinoscopy of the CMS, sphenopalatine,
and conchofrontal sinuses) is positioned 2 cm rostral and 2 cm ventral to the medial
canthus of the eye (Fig. 10).10 The most reliable RMS trephine site in mature horses is
positioned 40% of the distance between the rostral end of the facial crest and the medial
canthus of the eye, and 1 cm ventral to a line joining the infraorbital foramen and the
medial canthus (see Fig. 10).10 The trephination technique involves the following (Fig. 11):
1. The horse is sedated routinely using an a2-agonist plus butorphanol.
2. The skin at the trephination site is clipped and aseptically prepared.
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Fig. 10. (Left) Site for frontal sinus trephine portal. (Right) Sites for rostral (RMS) and caudal
(CMS) trephine portals. (From Barakzai S. Handbook of equine respiratory endoscopy. Edinburgh, UK: Elsevier; 2006; with permission.)
3. A total of 1 to 2 mL of local anesthetic solution (eg, 2% lidocaine or mepivacaine) is
infiltrated subcutaneously.
4. A 1.5- to 2.5-cm linear incision is made in the skin and the underlying periosteum;
the size of the incision depends on size of the trephine being used.
5. Through this incision, the bone is trephined using a 1.0- to 1.5-cm diameter steel
drill bit or a Galt trephine. Using self-retaining retractors may prevent damage to
the skin and periosteum during trephination. Care should be taken that only a short
length of the trephine is introduced into the sinus to avoid damaging intrasinus
Fig. 11. (A) Frontal sinus trephination being performed with a modified drill bit (with T-bar
welded on). (B) Frontal sinoscopy being performed.
Standing Equine Sinus Surgery
structures (the ethmoid bones in particular) and inducing intraoperative
hemorrhage.
6. If ventral conchal bulla fenestration will be performed, a second 8- to 10-mm diameter trephine opening can be made immediately below the original site to allow
enough room for forceps/rongeurs manipulation and extraction of the bulla under
endoscopic guidance.
7. The endoscope is introduced into the sinus and sinoscopy performed. A lavage
tube or Foley catheter can then be placed in the sinus and secured as appropriate.
If an in-dwelling tube is not left in situ, the incision may be closed primarily.
Standing Sinus Flap Surgery
Techniques for standing sinus flap surgery can be broadly split into 2 categories: those
that use chisels or a bone saw to produce a 3-sided rectangular bone flap, which may
be discarded or retained (Fig. 12), and those that use a large trephine to remove a disc
of frontal bone, which is discarded (Fig. 13).11 Horses require preoperative antibiosis,
heavy sedation, and systemic analgesia and direct infiltration of the surgical site with
local anesthetic before performing sinus flap surgery. Instillation of local anesthetic
solution into the sinus lumen either before osteotomy (via a trephine hole) or after
the bone flap is elevated also improves patient compliance when exploring the sinus
interior and removing material from the sinuses.
Once the abnormal sinus contents have been evacuated (Figs. 14 and 15), the bone
flap is replaced if possible (i.e., if it still has good periosteal and soft tissue attachments) and may be secured with cerclage wires before routine closure of the subcutaneous tissues and skin. Alternatively, cutting the osteoplastic flap at a 45 angle
prevents depression of the flap into the sinus interior once it is replaced, and in these
cases, use of cerclage wire may not be necessary. The bone flap is not retained if it is
made using the large circular trephine technique.11 Retention of the bone flap enhances the cosmetic result, particularly if a large nasofrontal osteotomy is made,
which includes the curved part of the nasal bone. Inclusion of periosteum in the wound
closure is believed to be important for sealing the sinus if the bone flap is not retained.
Postoperative sinus lavage is nearly always indicated after sinus surgery, although
overzealous lavage in the early stages (eg, within the first 24–48 hours) may be associated with increased incisional dehiscence because lavage fluid leaks into the periincisional tissues.
Fig. 12. (A, B) Oscillating bone saw being used to create hinged bone flap in the maxillary bone.
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Fig. 13. (A, B) Frontal sinus osteotomy technique using a large Galt trephine. The disc of
bone is discarded. (Courtesy of G. Quinn, BVSc Cert ES, Dipl. ECVS, Hamilton, New Zealand.)
MINIMALLY INVASIVE TECHNIQUES FOR ENLARGING THE SINONASAL OSTIUM
Balloon Sinuplasty
An endoscope-guided technique for enlarging the sinonasal ostium has been
described as a potential treatment for horses with reduced drainage from the
sinuses secondary to chronic sinusitis.12 The technique was adapted from use in
human beings and uses a dilating balloon catheter with a 12-mm diameter, 80-mmlong balloon, which is passed into the nasomaxillary ostium via the nasal cavity under
endoscopic guidance. A specially modeled balloon introducer was used to facilitate
correct positioning and the balloon was then dilated to a pressure of 6 atmospheres
for 30 seconds. This dilatation was repeated 2 times. Inflation of the balloon effectively
crushes the thin ventral conchal bulla, thus enlarging the sinonasal ostium. The results
of the procedure in clinical cases of equine sinusitis have yet to be published.
Laser Vaporization of Dorsal Turbinate
Laser vaporization of dorsal turbinate effectively creates a new sinonasal ostium in the
dorsal nasal concha, and thus allows for endoscopic evaluation of the sinuses with the
scope passed per nasum and may also act as a portal for sinonasal drainage.13 Under
endoscopic guidance, a diode laser fiber with a contact probe was passed into the
Fig. 14. Maxillary sinusotomy of chronic sinusitis case showing inspissated pus and sequestrae of nasal bones in the CMS.
Standing Equine Sinus Surgery
Fig. 15. (A) Large sinus cyst and granulation tissue with mycotic infection (diagnosed on histopathology) being removed through a bilateral frontal flap. (B) Postoperative appearance.
nasal passage through a custom-built laser introducer rod and used to create a stoma
in the caudal, medial aspect of the turbinate overlying the dorsal conchal sinus.13 This
location in the nasal turbinates was chosen because it has the thinnest nasal mucosa,
and therefore presumably the least vascularity. Sinoscopy was then performed via the
new stoma to identify structures within the conchofrontal sinus and caudal maxillary
sinus. The procedure was performed first in cadavers and then in standing sedated
horses. In 4 of the 5 live horses, hemorrhage was reportedly minimal, and a stoma large
enough to pass an endoscope through (approximately 1 cm2) was successfully
created.13 Repeat endoscopy revealed that the stoma persisted for at least 5 weeks.
Four horses had adhesion formation between the stoma and the nasal septum. The authors of this article13 recognized that a stoma in the dorsal conchal sinus may not be
optimal for sinus drainage because mucociliary clearance occurs toward the anatomic
nasomaxillary ostium and not toward the surgically created stoma. Application of the
technique in clinical cases and longer-term follow-up is necessary before final conclusions of this technique’s efficacy can be made.
POSTOPERATIVE CARE
The sinus mucosa is extremely sensitive and only very dilute solutions of antiseptic, if
any, should be used to lavage the sinuses. Solutions containing soap (ie, surgical
scrubs) must not be used for sinus lavage. The primary purpose of sinus lavage is
to physically dislodge and dilute material in the sinus, rather than provide antibacterial
action. Lavage should therefore be performed 2 to 3 times daily with large volumes of
fluid (3–5 L) (Fig. 16). Options for sinus lavage solutions are shown in Table 3.
COMPLICATIONS OF STANDING SINUS SURGERY
Hemorrhage
Hemorrhage is rarely associated with sinus trephination unless the surgeon inadvertently hits the ethmoturbinates or other intrasinus structure with the trephine. Even if
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Fig. 16. Postoperative sinus lavage being performed using a large volume of nonsterile
saline.
this occurs, in most cases hemorrhage will be self-limiting. Elevating the head of the
sedated horse often helps reduce bleeding.
A degree of hemorrhage always occurs when sinus flap surgery is performed,
because the sinus mucosa is a vascular tissue. Hemorrhage will be particularly
copious if a surgical fenestration is made between the sinuses and the nasal cavity
(Fig. 17), because the nasal mucosa is highly vascular. Sinonasal fenestration is not
Table 3
Sinus lavage solutions
Solution
Advantages
Disadvantages
Povidone iodine 0.05%
Inexpensive, antibacterial,
and antifungal activity
Irritant, particularly if
inadequately diluted
Solution is radio-opaque
and can result in artifacts
in postlavage radiographs
Sterile saline (0.9%
sodium chloride)
Isotonic and least irritating
to tissues
Expensive because large
volumes (z3–5 L) are
required bid/tid
Isotonic saline (9 g salt
dissolved in 1 L water)
Inexpensive and isotonic,
and therefore preferable
to plain water
Not sterile and no
antibacterial action
Tap water
Inexpensive
Hypotonic, and therefore
increases edema of sinus
mucosa
Not sterile and no
antibacterial action
Standing Equine Sinus Surgery
Fig. 17. Sinonasal fenestration using a stomach tube passed through the rostral aspect of
the VCS. Note the end of the tube coming out of the nostril. This sinonasal fenestration
technique causes minimal nasal hemorrhage, but the fistula tends to close within a month
or so after surgery.
indicated often in sinusitis cases, and the free flow of blood and lavage fluid down the
nasal cavity of horses undergoing sinusotomy will confirm this. We have experience of
using a bipolar vessel sealing device (Ligasure TM, Covidien, Dublin, Ireland) for
creating a bloodless sino-nasal fenestration in some standing surgery cases with
the instrument introduced via a naso-frontal flap, however the nasal and sinus mucosa
must be very well anaesthetised prior to instrument application. Hemorrhage associated with sinus surgery tends to be reduced in sedated standing horses compared
with anesthetized horses, because of the elevated head position of the standing horse.
Nonetheless, hemorrhage always occurs to some degree, and measures to control it
must be within easy reach during standing sinus flap surgery. These measures include
local application of pressure and packing the sinuses and nasal cavity with a long sterile
piece of cotton gauze (Fig. 18) or a sock-and-bandage pack. Use of topical adrenaline
is often not effective because of the amount of hemorrhage that quickly dilutes it and
carries it away from the area to which it was applied. Appropriate intravenous fluid therapy, and facilities to collect and administer whole blood, should be available in case
they are required. The authors have had some success using chitosan-impregnated
bandages in cases in which controlling intraoperative hemorrhage was challenging.
Patient Noncompliance
Patient noncompliance is extremely rare for sinus trephination techniques, but is
observed more often during standing flap procedures, particularly during creation of
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Fig. 18. Long bandage packing passed via the maxillary flap, through a surgically created
sinonasal fistula, and out through the nostril. Note the horse had to be twitched for this
procedure.
the osteoplastic flap if chisels or a bone saw are used. Fenestration of the nasal
conchae and packing of the nasal cavity will cause resentment in most standing patients because the nasal aspect of the conchae is not only very vascular, but is well
innervated. Although sinonasal fenestration and packing are possible in the standing
sedated animal (see Fig. 18), horses with unreliable or fractious temperaments that are
anticipated to require sinonasal fenestration may be better subjected to general anesthesia in the first instance. When performing standing sinus flap surgery, resources
should be on-hand in case patient noncompliance results in a general anesthetic being
required to complete the procedure.
Postoperative Incisional Infections
Sinus surgery in patients with active sinusitis is classified as “dirty” surgery using
the National Research Council wound classification criteria (ie, transection of clean
tissues performed for the purpose of surgical access to a collection of pus). In addition, suture material used to close the subcutaneous tissues may act as a foreign
body and potentiate wound infections that occur. In an owner survey (n 5 178), the
authors found that the overall prevalence of surgical site infection was 10% (Dixon
and Barakzai, unpublished data, 2011). Fortunately, although the prevalence of wound
infection after sinus surgery is high, establishment of drainage and removal of remaining suture material (if appropriate) usually results in quick resolution of local infection
with no adverse long-term consequences.
Poor Cosmetic Result
Trephination
When a small trephine hole is made, an excellent cosmetic result should be seen, with
the defect being palpable but not visible. Occasionally, horses may develop suturitis at
the frontonasal or frontolacrimal skull sutures, and if a large trephine hole is made, a
small concavity may be visible at the surgical site.
Sinus flap surgery
Published cosmetic results of a 3-sided osteotomy technique with retention and wire
fixation of the bone flap resulted in an excellent cosmetic result (no visible evidence of
surgery) in 74% of cases, a good result (some discolored hair or a line in the hair) in
Standing Equine Sinus Surgery
18% of cases, and a fair/poor result (mild or marked facial distortion) in 7% of cases.14
In comparison, use of a large Galt trephine to remove a disc of frontal bone has been
reported to result in excellent/very good surgical results in only 47% of cases (no
visible evidence, irregular hair growth associated with the incision site, or a very slight
concavity), a good result (mild to moderate asymmetry as a result of a slight proliferative frontonasal suture reaction or mild concavity at the surgical site) in 36%, and a
poor result (because of marked periostitis or concavity of the frontal bone) in
13%.11 Some surgeons also advocate application of a compression bandage placed
around the head in a figure-of-8 pattern postoperatively to improve the cosmetic
result; however, this has not been effective in the authors’ experience.
Recurrence of Sinusitis
Recurrence of sinusitis after trephination and lavage is usually attributable to an
ongoing underlying problem, such as failure to remove inspissated pus from some
compartment, the residual presence of an intrasinus mass, or an undetected infected
cheek tooth. The recurrence of clinical signs is an indication to refer the horse for
further diagnostics and sinus flap surgery, if appropriate.
Recurrence of clinical signs after sinus flap surgery is reported to occur in 13% to
28% of cases.11,14,15 These patients usually require some form of further investigation
and/or surgical intervention and are often good candidates for computed tomographic
examination if the cause of recurrence is not obvious.
REFERENCES
1. Dixon PM, Parkin TD, Collins N, et al. Equine paranasal sinus disease: a longterm study of 200 cases (1997-2009): ancillary diagnostic findings and involvement of the various sinus compartments. Equine Vet J 2012;44:267–71.
2. Barakzai SZ, McAllistair H. Radiography of the upper respiratory tract. In:
McGorum BJ, Robinson NE, Schumacher J, et al, editors. Equine respiratory
medicine and surgery. Edinburgh (United Kingdom): WB Saunders; 2006.
p. 151–74.
3. Henninger W, Frame EM, Willmann M, et al. CT features of alveolitis and sinusitis
in horses. Vet Radiol Ultrasound 2003;44:269–76.
4. Cissell DD, Wisner ER, Textor J, et al. Computed tomographic appearance of
equine sinonasal neoplasia. Vet Radiol Ultrasound 2012;53:245–51.
5. Textor JA, Puchalski SM, Affolter VK, et al. Results of computed tomography in
horses with ethmoid hematoma: 16 cases (1993–2005). J Am Vet Med Assoc
2012;240:1338–44.
6. Dacre I, Kempson S, Dixon PM. Pathological studies of cheek teeth apical infections in the horse: 5. Aetiopathological findings in 57 apically infected maxillary cheek teeth and histological and ultrastructural findings. Vet J 2008;178:
352–63.
7. Staszyk C, Bienert A, Bäumer W, et al. Simulation of local anaesthetic nerve block
of the infraorbital nerve within the pterygopalatine fossa: anatomical landmarks
defined by computed tomography. Res Vet Sci 2008;85:399–406.
8. Bardell D, Iff I, Mosing M. A cadaver study comparing two approaches to perform
a maxillary nerve block in the horse. Equine Vet J 2010;42:721–5.
9. Barakzai SZ, Knowles J, Kane-Smyth J, et al. Trephination of the equine rostral
maxillary sinus: efficacy and safety of two trephine sites. Vet Surg 2008;37:
278–82.
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10. Barakzai SZ. Sinoscopy. In: Handbook of equine respiratory endoscopy. Edinburgh (United Kingdom): Elsevier; 2006. p. 118–32.
11. Quinn GC, Kidd JA, Lane JG. Modified frontonasal sinus flap surgery in standing
horses: surgical findings and outcomes of 60 cases. Equine Vet J 2005;37:
138–42.
12. Bell C, Tatarniuk D, Carmalt J. Endoscope-guided balloon sinuplasty of the
equine nasomaxillary opening. Vet Surg 2009;38:791–7.
13. Morello SL, Parente EJ. Laser vaporization of the dorsal turbinate as an alternative method of accessing and evaluating the paranasal sinuses. Vet Surg 2010;
39:891–9.
14. Dixon PM, Parkin TD, Collins N, et al. Equine paranasal sinus disease: a long term
study of 200 cases (1997–2009): treatments and long-term result of treatments.
Equine Vet J 2012;44:272–6.
15. Tremaine WH, Dixon PM. A long-term study of 277 cases of equine sinonasal disease. Part 2: treatments and results of treatments. Equine Vet J 2001;33:283–9.
16. Perkins JD, Windley Z, Dixon PM, et al. Sinoscopic treatment of rostral maxillary
and ventral conchal sinusitis in 60 horses. Vet. Surg 2009;38:613–9.
S u r ge ry o f th e Si n u s es a nd
Eyes
Jennifer A. Schleining,
DVM, MS
KEYWORDS
Sinusitis Sinusotomy Enucleation Ocular squamous cell carcinoma
Eye surgery
KEY POINTS
Sinus lavage for the treatment of frontal and maxillary sinusitis can be very effective and is
not difficult when the appropriate landmarks are identified.
Conditions of the eye and eyelids necessitating surgery are common.
When early intervention is performed, the outcome is generally favorable.
Temporary tarsorrhaphy can be an effective means of supporting eyelid laceration repair
and corneal preservation during periods of facial nerve paralysis.
Conditions of the head requiring surgery in cattle are not uncommon when considering
the incidence of conditions such as ocular squamous cell carcinoma and requests for
surgical dehorning. Surgery involving the eyes in cattle is relatively common, whereas
surgery of the paranasal sinuses is less common. Generally speaking, however, surgery for conditions of the head tend to have a more favorable prognosis when there
is early intervention.
PARANASAL SINUSES
Cattle have 6 paranasal sinuses: the frontal, maxillary, palatine, lacrimal, sphenoid,
and conchal.1 Even though disease can affect any of these sinuses, practically and
clinically, only the frontal and the maxillary gain attention of the clinician. Similar to
the horse, the frontal sinus is very large. However, in cattle, the frontal sinus is separated into multiple compartments with the caudal frontal sinus being the most expansive, extending into the horn (if present) of mature animals. This extension is often
referred to as the cornual diverticulum. A second diverticulum is located behind the
orbit and is identified as the postorbital diverticulum.2 The further compartmentalization of the caudal frontal sinus by irregular osseous and membranous partitions can
The author has nothing to disclose.
Lloyd Veterinary Medical Center, Department of Veterinary Diagnostic and Production Animal
Medicine, Iowa State University, 1809 South Riverside Drive, Ames, IA 50011-3169, USA
E-mail address: [email protected]
Vet Clin Food Anim 32 (2016) 571–591
http://dx.doi.org/10.1016/j.cvfa.2016.05.004
vetfood.theclinics.com
0749-0720/16/$ – see front matter Ó 2016 Elsevier Inc. All rights reserved.
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make successful treatment of purulent sinusitis a challenge due to the inability to thoroughly and completely lavage the sinus. The frontal sinus communicates with the
nasal passage via multiple fenestrations into the ethmoid meatuses.1 In longstanding
or chronic cases, effective lavage may be achieved only with a frontal sinus flap. Within
the maxillary sinus are contained the tooth roots of the upper premolar and molar
teeth. Hence, in immature animals, the sinus is relatively small, whereas in older cattle,
it becomes larger as the cheek teeth are extruded. The maxillary sinus communicates
with the nasal passage through the nasomaxillary opening. However, this communication lies high on the medial wall of the sinus allowing fluid to accumulate below this
opening in the rostral maxillary sinuses and palatine sinuses rather than draining out
the nasal passages.1
CONDITIONS OF THE PARANASAL SINUSES
Sinusitis
Frontal sinusitis in cattle is frequently seen as a sequela to dehorning procedures in
which the frontal sinus was entered via the horn base following horn removal. It also
can be seen following traumatic fracture of the horn, tipping of horns (Figs. 1 and
2), sequestration of bone secondary to dehorning, and frontal bone fractures. Environmental and skin contaminants gain access to the caudal frontal sinus through these
openings, causing inflammation, and in some cases, results in bacterial infection leading to accumulation of purulent material within the sinuses. Clinical signs of sinusitis
can include lethargy, inappetance, purulent nasal discharge, head pressing, head
tilt, and in chronic cases, distortion of the bones overlying the affected sinuses. There
Fig. 1. A 5-year-old crossbred cow presented for unilateral nasal discharge and recent history of tipping the end of the horns.
Surgery of the Sinuses and Eyes
Fig. 2. Close up of the tip of the left horn showing communication of the horn with the
caudal frontal sinus.
may be a history of recent dehorning, but in a study involving 12 cases of chronic
sinusitis, only 8 of the affected animals had been dehorned within the 12 months
before hospital admission for sinusitis.3 Three cattle who did not have a history of
dehorning had a history of recent respiratory disease. Physical examination may identify fever, foul odor to the breath or nasal secretions, draining tracts overlying a previous dehorning site or site of trauma, and a dull sound, and perhaps pain, on
percussion of the affected sinus. Radiography confirms the presence of fluid
within the affected sinus. Usually, lateral and dorsoventral projections are enough to
confirm the diagnosis; however, oblique views, including a rostrocaudal oblique
view to set off the caudal frontal sinuses, can be helpful in delineating the extent of
the fluid and structures affected (Fig. 3). Culture of the fluid with subsequent sensitivity
of bacterial isolates to common antimicrobials will help direct antibiotic treatment. Truperella pyogenes is the most common isolate from sinusitis following dehorning,
whereas Pasteurella multocida is the most common isolate in cases without a history
of dehorning.3,4 As such, penicillin is a reasonable choice for therapy while awaiting
sensitivity results. Antimicrobial therapy should be instituted along with sinus lavage.
In acute cases of sinusitis, lavage can be performed through a small hole created in the
caudal frontal sinus using a 4-mm Steinman pin inserted into a hand chuck. This hole
will accommodate the male end of a fluid administration set or Simplex outfit providing
for daily or twice daily lavage. In a study of 60 cattle with sinusitis, 4 different lavage
solutions were compared. Cattle underwent sinus lavage with an unreported volume
of fluid every 48 hours for 10 days. In that study, of the 15 cattle randomly assigned
to each treatment group, 13 cases lavaged with 5% diluted povidone-iodine solution
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Fig. 3. A rostrocaudal oblique view of the caudal frontal sinuses showing a fluid-filled left
frontal sinus. The metallic probe is placed into a draining tract communicating with the
sinus.
achieved resolution compared with only 3 in the 0.9% sodium chloride group indicating povidone-iodine solution diluted to 5% resulted in a statistically better clinical
outcome than using saline alone.5 Chronic cases of sinusitis, however, usually require
more invasive approaches to the sinus, which could include trephination or osteotomy
(bone flap).
Maxillary sinusitis is uncommon and most commonly occurs secondary to an
infected or fractured tooth root. Clinical signs include facial deformation (Fig. 4),
Fig. 4. Bilateral maxillary sinus swelling in a 4-year-old Wagyu bull.
Surgery of the Sinuses and Eyes
unilateral mucopurulent nasal discharge, altered head carriage, and sometimes
decreased appetite secondary to pain during mastication. Radiography should be
performed to rule out dental disease as a cause of sinus swelling. If tooth root infection
is diagnosed, sinusotomy with tooth repulsion and lavage should be performed and is
curative. Differentials for maxillary swelling should also include neoplasia and other
bacterial infection, such as Actinobacillosis lignieresii (Fig. 5).
Sinus Cyst
Cysts of the paranasal sinuses have been described in the literature. These include
maxillary sinus cyst, sinonasal cysts, and conchal cysts.6–8 Clinical signs include
mucopurulent nasal discharge, increased respiratory effort, or noise due to partial
or complete nasal obstruction, and/or facial deformity. Radiography will often identify a well-demarcated soft tissue opacity within the affected sinus with deviation of
normal structures. Computed tomography can be a very useful adjunct to radiography when the full extent of the cyst is not able to be determined and/or to identify
multiple cysts. Additionally, endoscopy should be considered for masses that enter
the nasal passage. Treatment of sinus cysts will be predicated by the location of
the cyst, but can include removal via the nasal passage under endoscopic guidance or via a maxillary or frontonasal bone flap technique. Complete removal of
the cyst lining appears to be curative in cattle. In a study of 10 cattle undergoing
surgical removal of paranasal and conchal sinus cysts, 9 returned to production
and had no recurrence.9 Not all well-demarcated soft tissue opacities in the sinuses
or nasal passages should be assumed to be sinonasal cysts, however. Neoplasia
can present very similarly and should be included in the differential list for paranasal
sinus disease (Fig. 6).
Fracture
Depression fracture of the frontal bone, nasal bone, and orbit can occur resulting
acutely in increased respiratory effort due to swelling, hemorrhagic nasal discharge
(Fig. 7), abnormal head carriage, and inappetance depending on the severity and
Fig. 5. Caudoventral radiograph of a bull with bilateral maxillary swelling diagnosed with A
lignieresii sinusitis. Note the severe bone destruction and remodeling.
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Fig. 6. Frontal plane computed tomography image at the level of the eyes in a 2-year-old
Angus cow with lymphosarcoma believed to have been a sinonasal cyst. Note the right
maxillary sinus is filled with fluid with a thick lining.
location of the fracture. The incidence of fracture is less than that reported in horses
likely because of differences in behavior and animal use.10 In cases of depression fracture, surgical repair can be performed under general anesthesia using bone reduction
instruments or a 3.5-mm screw inserted proud into the fractured fragment to aid in
reducing the fragment back into alignment. Cerclage wire may or may not be
Fig. 7. An endoscopic image showing hemorrhage from the ethmoid meatus in a 5-year-old
Simmental bull with a frontal bone fracture.
Surgery of the Sinuses and Eyes
necessary to keep the fragment(s) in position. Orbital fractures can be repaired with
various orthopedic techniques including string-of-pearls plates, dynamic compression plates, or cerclage wire depending on the configuration of the fracture. Minor
closed fractures with minimal displacement may not require repair.
TREPHINATION
Preoperative Planning
Trephination can be completed using either a Galt or Michele trephine (Fig. 8). The
advantage of the Galt trephine is that it results in a larger access portal to the sinus.
The appropriate site should be chosen to best access the affected sinus (Fig. 9).
Box 1 lists the supplies needed for trephination of the paranasal sinuses.
Preparation and Patient Positioning
The patient should be restrained in a hydraulic chute or manual head catch. A halter
should be used to further restrain the head to minimize movement during the procedure. The trephine site should be clipped allowing for at least 2-inch margins around
the proposed site of trephination. A rough preparation of the site should be conducted
with chlorhexidine scrub followed with alcohol. Ensure that these solutions do not contact the eyes, as they will cause severe chemical keratitis. A large bleb of lidocaine
should be placed subcutaneously at the trephination site followed by a more thorough
cleansing of the site with scrub and alcohol.
SURGICAL APPROACH AND PROCEDURE
Using a scalpel blade, a full-thickness circular area of skin should be removed corresponding to the size of the trephine extending to the periosteum of the frontal or maxillary bone. The trephine should then be used in a clockwise rotation to remove a
section of bone allowing access into the sinus. At this time, a sample of the fluid within
the sinus should be collected for culture and sensitivity. The sinus may now be lavaged
and/or investigated further using flexible endoscopy if necessary.
IMMEDIATE POSTOPERATIVE CARE
The trephine sites should be left open to heal by second intention. Covering the trephination sites is recommended to keep debris and further contaminants from entering
Fig. 8. A Michele trephine on the left and a Galt trephine on the right.
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Fig. 9. The circles indicate the site(s) of trephination for each sinus, and shaded areas are the
frontal and maxillary sinuses. (From Gaughn EM, Provo-Klimek J, Ducharme NG. Surgery of
the bovine respiratory and cardiovascular systems. In: Fubini S, Ducharme N, editors. Farm
animal surgery. St Louis (MO): Saunders; 2004. p. 148; with permission.)
the sinus. A stent bandage using #2 polymerized caprolactam (Braunamid; Braun) (or
other nonabsorbable suture material) is easily made by placing 2 loose interrupted sutures through the skin perpendicular to the surgical site, one above and one below the
incision. A 12-inch segment of umbilical tape should be passed through each suture. A
roll of 4 4 gauze sponges or a 4-inch roll gauze can then be placed over the incision
and secured in place by the umbilical tape. The bandage may then be removed and
replaced for subsequent sinus lavage procedures or alternatively left in place until
the sinusotomy has been obscured by granulation tissue. Postoperative care
also should include the use of anti-inflammatory medications such as meloxicam
Box 1
Supplies needed for sinus trephination
Clippers with a #40 blade
Lidocaine
Chlorhexidine scrub and alcohol for site preparation
Sterile trephine (Galt or Michele)
Sterile surgical gloves
#10 or #15 scalpel blade and handle
Gauze sponges
Culturette or sterile syringe
#2 Braunamid suture
One-half–inch Braunamid suture
Surgery of the Sinuses and Eyes
(0.5–1.0 mg/kg by mouth once a day or every other day) or flunixin meglumine
(1.1–2.2 mg/kg intravenously (IV) as needed).
OSTEOTOMY (BONE FLAP)
Preoperative Planning
List of supplies and instruments needed to perform a sinus osteotomy (Box 2).
Preparation and Patient Positioning
Although a frontal sinus bone flap procedure could be done in the standing animal, it is
generally recommended to perform this procedure in the anesthetized animal. Maxillary bone flaps should be performed under general anesthesia. General anesthesia
should be maintained with inhalant anesthesia with an appropriately inflated endotracheal tube cuff given the propensity of significant bleeding into the nasal cavity if the
nasal concha are required to be punctured for creation of drainage. The patient should
be placed in lateral recumbency with the affected sinus(es) up. The surgical site should
be clipped and aseptically prepared as for any other surgical site.
SURGICAL APPROACH AND PROCEDURE: FRONTAL SINUS
Using a scalpel blade, a 3-sided, rectangular incision should be made extending to the
bone and including the periosteum. The location for the incision should be as follows:
the caudal margin should be a line extending from midline to a point bisecting the supraorbital foramen and poll, the lateral margin should extend from the caudal margin to
the level of the center of the orbit approximately 3.5 to 4.0 cm medial to the medial
canthus of the eye taking care to avoid the supraorbital foramen, and the rostral
margin extends from midline to the rostral extent of the lateral margin. The periosteum
should be gently reflected with a blunt periosteal elevator along with the skin and subcutaneous tissue. An oscillating bone saw or mallet and osteotome should then be
used to create osteotomy incisions following the margins of the skin incision. The
osteotomy incisions should be created at an approximately 45 oblique angle through
the bone (Fig. 10). The rostral and caudal incisions at midline should be notched to
facilitate “hinging” the flap axially. The flap may then be elevated and hinged.
Box 2
Supplies needed to perform an osteotomy
Clippers with a #40 blade
Chlorhexidine scrub and alcohol for site preparation
Sterile surgical gloves
#10 or #15 scalpel blade and handle
Basic surgical pack
Oscillating bone saw or mallet and chisels/osteotome set
Gauze sponges
Culturette or sterile syringe
6-inch roll gauze with fine weave
0 or 2-0 absorbable suture material
0 absorbable or nonabsorbable suture material or stainless steel staples for skin closure
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Fig. 10. Location for the skin and osteotomy incisions for a frontal sinus bone flap. Note the
angled notches at the axial border to facilitate flap hinging. The osteotomy angle is illustrated in the inset.
Depending on the chronicity of the condition and location of osseous structures within
the sinuses, an osteotome may be necessary to manually dissect attachments of the
flap to the sinus cavity. Fluid should now be collected for cytology and/or culture and
sensitivity. Copious lavage and debridement of the sinus should be undertaken paying
special attention to the postorbital diverticulum and other deep structures within the
sinus. If drainage is not well established, a fenestration into the nasal passage may
be made through the wall of the conchal sinuses using a probe, large hemostats, or
other blunt instrument. This usually results in profuse hemorrhage and packaging of
the sinus with fine-weave roll gauze should be performed. The front tail of the gauze
should be exited the fenestration and secured to the nasal fold with a simple interrupted or mattress suture. A single, small tight knot should be placed at the back tail so
that when the packing is removed, the visualization of the knot confirms that the entire
packing was removed. A second option for packing the sinus includes exiting the
gauze packing out a corner of the osteotomy site after removing a corner of the
bone flap. If this option is chosen, a knot should not be used at the end of the gauze.
This method of packing, however, will result in an open incision that will require further
aftercare after the packing is removed. Following packing of the sinus cavity, the bone
flap should be replaced. It is not necessary to suture the bone flap. The periosteum
and subcutaneous tissues should be closed separately using 2 to 0 absorbable suture
material. The skin can then be closed either with stainless steel staples or nonabsorbable suture material.
SURGICAL APPROACH AND PROCEDURE: MAXILLARY SINUS
Using a scalpel blade, a 3-sided, rectangular incision should be made extending to the
bone and including the periosteum. The location for the incision should be as follows:
the caudal margin should begin at the approximate level of the medial canthus of the
eye 4 to 5 cm distal to the orbit extending distally to the level of the facial tuberosity,
the ventral margin should begin at this point and extend rostrally 5 to 7 cm following a
line drawn from the zygomatic arch to the facial tuberosity, the rostral margin then extends from this point dorsally 5 cm parallel with the caudal margin.2 Care should be exercised during the incision so as to not incise the facial vein as it courses across the
Surgery of the Sinuses and Eyes
maxillary sinus. The osteotomy should then proceed as described previously with the
bone flap hinged on its dorsal margin (Fig. 11). In young animals, the tooth roots will
occupy much of the sinus and care should be taken not to disrupt normal roots. If a tooth
is removed, the void should be filled with a temporary plug. The socket of the missing
tooth should be packed with either a methylmethacrylate plug or rolled gauze secured
to umbilical tape, which exits the sinusotomy site at a small removed corner. Following
tooth removal and/or sinus lavage, closure of the osteotomy site should be performed
as described previously. Methylmethacrylate plugs are left to fall out on their own,
whereas gauze plugs should be changed every 5 to 7 days until there is no longer communication between the oral cavity and the sinus. The gauze packing should be secured with
very long pieces of umbilical tape to allow the packing to be removed from the oral cavity
through the mouth, a new packing secured to the umbilical tape, and then the umbilical
tape again pulled taut from the sinusotomy site until the new packing is again secure
within the socket. The tails are tied in a bow around a second roll gauze to keep the
plug in place. An oral speculum is required for this packing change. The disadvantage
of the methylmethacrylate plug is that if it falls out prematurely, feed material may become
impacted into the sinus through the fistula requiring further intervention.
IMMEDIATE POSTOPERATIVE CARE
The surgical sites should be kept clean. Any sinus packing should be removed in 24 to
48 hours and sinus lavage instituted if needed at that time. Postoperative care also should
Fig. 11. Location for a maxillary bone flap. Note the nasal packing secured to the right
nares.
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include the use of anti-inflammatory medications, such as meloxicam (0.5–1.0 mg/kg by
mouth SID – EOD) or flunixin meglumine (1.1–2.2 mg/kg IV as needed) and antimicrobial
therapy as indicated. The skin sutures or staples should be removed in 14 days.
EYES
Surgery involving the periorbital structures and eyes is relatively common in ruminants.
Conditions requiring surgery are varied and range from trauma to neoplasia to
congenital.10
SURGICAL CONDITIONS OF THE EYE
Neoplasia
Ocular squamous cell carcinoma
Squamous cell carcinoma of the eye and associated structures is common in cattle
and can affect the eyelids, the nictatans (third eyelid), the conjunctiva, and cornea
(Fig. 12).10,11 Although the complete etiology of ocular squamous cell carcinoma
(OSCC) is not totally understood, cattle lacking pigment of the area around the eyes
and exposed to high levels of UV sunlight have a higher incidence. The size and location of the lesion will likely determine the treatment. Smaller, well-defined, lesions
(<50 mm) lend themselves to successful treatment with cryotherapy, hyperthermia,
or surgical excision. Larger lesions provide more challenges and may require enucleation, sometimes involving extensive removal of periorbital tissues, to completely
Fig. 12. An extensive OSCC of the periorbital tissues in a 6-year-old Hereford cow.
Surgery of the Sinuses and Eyes
resolve the condition. When only the third eyelid is involved, the third eyelid may be
removed without worry of further problems.
Lymphosarcoma
Neoplasia should always be included on a differential list for an animal presenting with
exophthalmos. Lymphosarcoma is the most common neoplastic disease of the orbit in
cattle and tends to be fairly invasive.12 Digital palpation of the orbit should occur
because foreign bodies can also cause retrobulbar or orbital abscesses resulting in
clinical symptoms that may mimic lymphosarcoma. If lymphosarcoma is suspected,
a fine-needle aspirate, biopsy, serology for bovine leukosis virus, and/or palpation
of regional lymph nodes and abdominal lymph nodes via rectal palpation may assist
in arriving at a final diagnosis. Cattle with lymphosarcoma can sometimes be salvaged
long enough to birth or wean a calf, but quality of life should be taken into account
when deciding on how to progress. Exenteration of the orbital contents may prolong
the life of the animal, but in the author’s experience the tumor tends to reoccur very
rapidly and aggressively. Cattle with any outward signs of lymphosarcoma will be
severely discounted at market and the carcass condemned at slaughter.
Trauma
Lacerations of the eyelids, although not common, do occur and may require surgical
repair (Fig. 13). Depending on the location and extent of tissue trauma, this may be
best done under general anesthesia in the interest of cosmesis, functionality of the
lid, and integrity of the repair. It is important to perform a full ophthalmic examination
when presented with an eyelid laceration to rule out globe trauma, corneal ulceration
or laceration, and the presence of conjunctival foreign bodies that may have occurred
during the traumatic event. The tissues often will be edematous and may contain mucous exudate. Practitioners should avoid the temptation to remove skin flaps, especially when the eyelid margins are involved in the laceration. The integrity of the
margin is very important when considering the future functionality of the lid. Without
the lid margin, entropion may occur resulting in chronic corneal irritation and ulceration
from hair, or even worse, the eye may not be properly protected or able to maintain a
tear film resulting in chronic exposure keratitis and discomfort. All efforts should be
made to repair the eyelid.
Cryotherapy
List of supplies needed to perform cryotherapy of the eyelids or nictitating membrane
(Box 3).
The patient should be restrained in a hydraulic chute with the head further restrained
with a halter or hydraulic head restraint system. Topical ophthalmic anesthetic
Fig. 13. Eyelid laceration in a yearling crossbred heifer. (Photograph courtesy of Dr Josh Ydstie.)
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Box 3
Supplies needed for cryotherapy
Topical anesthetic (ie, Proparacaine)
Styrofoam coffee cup
Sterile lube
Cryotherapy unit (pen, gun, or other unit)
(proparacaine) should be generously applied to the eye. If the lesion is on the margin of
the eyelid, the rim of the Styrofoam cup can be removed, lubricated, and inserted between the lid and the eye serving as a barrier to the liquid nitrogen.
Using either a contact probe or an open spray tip, a double freeze thaw cycle should
be performed. The abnormal tissue should be frozen until either a thermocouple
placed in the skin deep to the mass reads 25 C or until an ice ball is observed
extending past the periphery of the mass. The second freeze cycle should occur
immediately after the mass has thawed.
An antibacterial ointment should be placed in the eye following cryosurgery. Edema
within the affected tissues will be evident within a few hours and is a normal sequela to
cryosurgery. This edema gradually subsides within the next few days without further
intervention. The eye should be relatively comfortable as cryotherapy results in death
of nerve endings at the site of cryogen application.
Hyperthermia
Box 4
Supplies needed for hyperthermia to remove eyelid masses
Topical anesthetic (ie, Proparacaine)
Handheld radiofrequency unit
Orbital retractor
The patient should be restrained in a hydraulic chute with the head further restrained
with a halter or hydraulic head restraint system (Box 4). Alternatively, if a tilt table is
available, the patient can be restrained in lateral recumbency with the affected eye
up. Topical ophthalmic anesthetic (proparacaine) should be generously applied to
the eye.
An orbital retractor (Fig. 14) should be gently placed behind the eye while avoiding
the muscles of the eye (Fig. 15). The retractor will prevent the eye from moving during
the procedure. The radiofrequency probes should then be placed in contact with the
mass and the mass consequently heated to 50 C. Care should be taken not to overlap
the direction of hyperthermia application on the cornea, as this may cause corneal
perforation.
Antimicrobial ointment should be placed in the eye at the conclusion of the procedure. The use of anti-inflammatory medications, such as meloxicam (0.5–1.0 mg/kg by
mouth SID – EOD) or flunixin meglumine (1.1–2.2 mg/kg IV as needed) also may be
used as indicated.
Surgery of the Sinuses and Eyes
Fig. 14. A bovine orbital retractor.
Enucleation
Box 5
Supplies needed to perform enucleation
Clippers with a #40 blade
Chlorhexidine scrub and alcohol for site preparation
Sterile surgical gloves
#10 or #20 scalpel blade and handle
Basic surgical pack with towel clamps
Mixter forceps or other 90 forceps
Gauze sponges
0 absorbable suture material
#2 Braunamid or other nonabsorbable suture material
Three options exist for removal of the eye. They are enucleation, exenteration, and
evisceration. Enucleation refers to the removal of the globe only. Exenteration refers
to removal of the globe and all orbital contents including muscles, periorbital fat,
and optic nerve and vessels. Evisceration is a procedure in which only the intraocular
contents of the eye are removed, leaving the globe intact. Enucleation is by and far the
most frequent surgical procedure used in bovine practice and is described here. The
reader is directed to other texts for detailed descriptions of the other procedures.
The patient should be restrained in a hydraulic chute with the head further restrained
with a halter or hydraulic head restraint system (Box 5). Alternatively if a tilt table is
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Fig. 15. The bovine orbital retractor placed behind the eye to prevent eye movement during
hyperthermia.
available, the patient can be restrained in lateral recumbency with the affected eye up.
If indicated, a broad-spectrum antibiotic can be administered at this time. The orbital
area should be generously clipped and a rough scrub performed to remove surface
debris. Care should be taken so as to not get scrub or alcohol into the eye. The eyelids
and orbit should then be anesthetized (see Edmonson MA: Local, Regional, and Spinal
Anesthesia in Ruminants, in this issue). Following tight apposition of the eyelids with a
continuous suture pattern, a final surgical scrub should be performed. Another method
of eyelid apposition is with the use of towel clamps rather than suturing the lids closed.
An advantage of this technique is that the towel clamps may be used for traction of the
globe during the surgical procedure.
An elliptical incision should be made 1 to 2 cm around the periphery of the eyelid
margins. Using a combination of blunt and sharp dissection and using the orbit as a
guide, the surgeon should proceed through the orbicularis oculi muscle and periorbital
fascia while avoiding penetration of the conjunctiva. The ligaments at the medial and
lateral canthi are substantial and will require sharp transection. After transection of the
ligaments, the globe should be freely moveable. Dissection should proceed into the
orbit transecting the oblique, rectus, and retractor bulbi muscles. When all
the muscular attachments to the globe have been removed a Mixter forceps or other
vascular clamp (such as a kidney clamp or large curved Kelly forceps) should be
applied to the optic nerve and vessels at the base of the eye. The globe should then
be sharply removed and, if possible, a ligature placed around the optic pedicle using
an absorbable suture material. At this time, further debridement of the orbit can occur
if necessary. The globe can then be lavaged before closure of the subcutaneous tissues with a 0 or 2 to 0 synthetic absorbable suture material capable of maintaining
Surgery of the Sinuses and Eyes
tension. Alternatively, if the pedicle is not able to be ligated effectively, the orbit can be
packed with roll gauze to provide hemostasis while the incision is being closed. The
gauze can then be removed just before placement of the final sutures in the subcutaneous layer. The lid margins should then be apposed using a continuous suture
pattern of the surgeon’s preference using #2 nonabsorbable suture (Fig. 16). If the animal is anticipated to rub at the surgical site postoperatively, a stent bandage can be
placed over the surgical incision to protect the integrity of the sutures. This is accomplished by placing loose simple interrupted sutures with #2 nonabsorbable suture material at the rostral and caudal borders of the orbit through which umbilical tape passes
in a “lacing” fashion. A rolled huck towel, laparotomy sponge, or rolled gauze can then
be placed over the incision and under the laces. The laces are then tightened to secure
the stent in place.
The surgical site should be monitored closely over the course of the next 3 to 5 days.
Postoperative swelling usually subsides within the first week as the hematoma within
the orbit resolves. The use of anti-inflammatory medications such as meloxicam (0.5–
1.0 mg/kg by mouth SID – EOD) or flunixin meglumine (1.1–2.2 mg/kg IV as needed)
should be considered. If present, the stent can be removed in 5 to 7 days and the
skin sutures in 14 days.
Laceration repair
Box 6
Supplies needed to repair eyelid lacerations
Dilute povidone-iodine solution (not scrub)
Clippers
Lidocaine
Topical anesthetic (ie, Proparacaine)
#15 scalpel blade and handle
Brown Adson thumb forceps
Gauze sponges
2-0 to 5-0 absorbable suture material
Scissors
If the laceration is small, the patient may be restrained in a hydraulic chute with the
head further restrained with a halter or hydraulic head restraint mechanism (Box 6).
However, if the laceration is extensive or requires meticulous repair based on the location or configuration of the laceration, general anesthesia is recommended. The laceration margins should be locally anesthetized with subcutaneous injection of lidocaine
and topical anesthetic liberally applied to the eye surface. The laceration should then
be prepped for surgery using 5% dilute povidone-iodine solution. The use of scrub formulations and alcohol will result in chemical keratitis and should be avoided!
The margins of the laceration should be carefully and minimally debrided to preserve as much tissue as possible. This is important for proper eyelid function after
the repair has healed. Flaps should not be removed and the tips of any flaps left
in situ even if they look like they will not survive. Full-thickness lacerations should
be repaired in 2 to 3 layers. The deep layer should include the fibrous tarsal plate,
which is very important in the repair process.10 The eyelid margins should be apposed
meticulously and carefully. There are numerous suturing techniques for this type of
587
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Schleining
Fig. 16. A completed enucleation surgery showing skin closure.
repair depending on the configuration of the laceration and the reader is directed to
ophthalmology texts for these specific suture patterns. The skin can be apposed in
simple interrupted or mattress suture patterns. Extensive laceration repairs may
require stenting after repair. This can occur in a number of different ways, including
temporary tarsorrhaphy. If the eye requires medicating postoperatively, a subpalpebral lavage system is recommended to be placed before the tarsorrhaphy.
If the animal is amenable, the repair should be warm compressed 2 to 3 times a
day to help reduce inflammation and pain. The use of anti-inflammatory medications,
such as meloxicam (0.5–1.0 mg/kg by mouth SID – EOD) or flunixin meglumine (1.1–
2.2 mg/kg IV as needed) should be considered. If indicated, the eye should be medicated through the subpalpebral lavage system with liquid medication or carefully at a
site distant from the repair with ointment. If there was extensive tissue damage, broadspectrum systemic antibiotics may be indicated. If a tarsorrhaphy was performed, it
should be removed in 7 to 10 days.
Tarsorrhaphy
Box 7
Supplies needed to perform a tarsorrhaphy
Lidocaine
Topical anesthetic (ie, Proparacaine)
2-0 nonabsorbable suture material
Rubber tubing (16 drops/s intravenous lines work well) cut into small pieces
Needle holders
Scissors
In cases such as described previously or when presented with an animal with facial
nerve paralysis (such as sometimes seen in listeriosis) a temporary tarsorrhaphy
can be a useful procedure to protect the laceration repair or the cornea from exposure
keratitis (Box 7).
The animal should be restrained in a hydraulic chute with the head further restrained
by a halter. A local injection of lidocaine should be performed subcutaneously at the
site of each suture. The eye should be liberally dosed with a topical anesthetic.
Surgery of the Sinuses and Eyes
The suture material should be placed through the rubber tubing. A partial-thickness
bite through the upper lid exiting along the eyelid margin should then be performed.
Next, the lower lid should be entered in the center of the eyelid margin opposite of
the exiting suture of the upper lid and exited through the skin. The suture should
then pass through a second piece of rubber tubing, the needle reversed, and the procedure repeated back through the lower lid and into the upper lid exiting near the upper rubber stent. The ends should then be tied together making a horizontal mattress
suture pattern with the stents. A second and, possibly third if needed, stent suture can
be placed to complete the procedure.
Postoperative care is minimal. The tarsorrhaphy sutures should be removed
when no longer needed, preferably within 2 weeks. When the sutures are not
removed in a timely fashion, large granulomas may form inhibiting normal lid function
(Fig. 17).
Fig. 17. Granuloma secondary to temporary tarsorrhaphy sutures left in place for 3 months.
Note the corneal scar and conjunctivitis from improperly placed suture.
589
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Schleining
CLINICAL RESULTS
When used on appropriately sized OSCCs (demarcated lesions <50 mm), cryotherapy
using a single freeze thaw cycle was curative in 66% of the lesions. When a double
freeze thaw cycle was used, 97% of the lesions regressed completely.13 Cryotherapy
can also be used adjunctively following surgical debulking of the mass. However,
because of the inability of the cryogen to effectively freeze deeper tissues, large tumors that invade deeper structures are not a candidate for cryotherapy. Hyperthermia
has also been reported to have a favorable outcome on ocular squamous cell carcinoma.14,15 In one study of 76 OSCCs, 60 tumors regressed completely after 1 hyperthermia treatment and another 9 regressed completely after a second treatment for an
overall cure rate of 90.8%.15 Tumors that are invasive or larger than 50 mm do not
respond well to hyperthermia and other treatments should be considered. In a
single-center retrospective study of 53 cattle undergoing enucleation, nearly 85% of
eyes were removed consequent to OSCC. Despite nearly 20% of the cattle having surgical site infection in the 3 weeks postoperatively, cattle undergoing enucleation in this
study largely were returned to production. The prognosis of the 22 cattle available for
long-term follow-up was very good with a very low recurrence rate.16
SUMMARY
Although surgery of the paranasal sinuses may not be an everyday occurrence, familiarity with the anatomy can improve the veterinarian’s comfort level and case
outcome. The most common reason for sinus surgery is sinusitis secondary to previous dehorning or respiratory disease. Sinus lavage in early cases of sinusitis has a high
success rate. Surgery of the eyes are more common given the incidence of OSCC and
conditions requiring enucleation. Small lesions may be amenable to treatment with
cryotherapy or hyperthermia, whereas larger lesions may require enucleation. Enucleation appears to have a good long-term outcome.
REFERENCES
1. Dyce KM, Sack WO, Wensing CJG. The head and ventral neck of the ruminants.
In: Textbook of veterinary anatomy. Philadelphia: Saunders; 2002. p. 633–6.
2. deLahunta A, Habel RE. Paranasal sinuses. In: Applied veterinary anatomy.
Philadelphia: Saunders; 1986. p. 51–3.
3. Ward J, Rebhun W. Chronic frontal sinusitis in dairy cattle: 12 cases (1978-1989).
J Am Vet Med Assoc 1992;201:326–8.
4. Gaughn EM, Provo-Klimek J, Ducharme NG. Surgery of the bovine respiratory
and cardiovascular systems. In: Fubini S, Ducharme N, editors. Farm animal surgery. St Louis (MO): Saunders; 2004. p. 146–8.
5. Silva L, Neto A, Campos S, et al. Evaluation of four different treatment protocols to
sinusitis after plastic dehorning in cattle. Acta Scientiae Veterinariae 2010;38:25–30.
6. McPike Mundell L, Smith B, Hoffman R. Maxillary sinus cysts in two cattle. J Am
Vet Med Assoc 1996;209:127–9.
7. Ross M, Richardson D, Hackett R, et al. Nasal obstruction caused by cystic nasal
conchae in cattle. J Am Vet Med Assoc 1986;188:857–60.
8. Cohen N, Vacek J, Seahorn T, et al. Cystic nasal concha in a calf. J Am Vet Med
Assoc 1991;198:1035–6.
9. Schmid T, Braun U, Hagen R, et al. Clinical signs, treatment, and outcome in 15
cattle with sinonasal cysts. Vet Surg 2014;43:190–8.
Surgery of the Sinuses and Eyes
10. Irby N. Surgical diseases of the eye in farm animals. In: Fubini S, Ducharme N,
editors. Farm animal surgery. St Louis (MO): Saunders; 2004. p. 429–59.
11. Tsujita H, Plummer C. Bovine ocular squamous cell carcinoma. Vet Clin North Am
Food Anim Pract 2010;26:511–29.
12. Rebhun WC. Ocular manifestations of systemic diseases in cattle. Vet Clin North
Am Large Anim Pract 1984;6:623–39.
13. Farris HE, Fraunhfelder FT. Cryosurgical treatment of ocular squamous cell carcinoma of cattle. J Am Vet Med Assoc 1976;168:213–6.
14. Grier RL, Brewer WG Jr, Paul SR, et al. Treatment of bovine and equine ocular
squamous cell carcinoma by radiofrequency hyperthermia. J Am Vet Med Assoc
1980;177:55–61.
15. Kainer RA, Stringer JM, Lueker DC. Hyperthermia for treatment of ocular squamous cell tumor in cattle. J Am Vet Med Assoc 1980;176:356–60.
16. Schulz KL, Anderson DE. Bovine enucleation: a retrospective study of 53 cases
(1998-2006). Can Vet J 2010;51:611–4.
591
Disorders of the Paranasal Sinuses
26
Henry Tremaine and David E Freeman
Introduction
Inflammation of the equine paranasal sinuses is a relatively uncommon disease that may be caused by primary
bacterial or mycotic infections (Mason 1975a), or can be
secondary to dental disease (van der Velden & Verzijlenberg
1984, Scott 1987, Tremaine & Dixon 2001a), facial trauma,
sinus cysts, progressive ethmoid hematoma or sinonasal
neoplasia (Mansmann & Wheat 1973, Gibbs & Lane 1987,
Tremaine & Dixon 2001a). Equine sinusitis is usually
unilateral but bilateral disease has been reported (Coumbe
et al 1987, Lane 1993, Tremaine & Dixon 2001a). There
is apparently no breed, age or gender predisposition to
sinusitis. Clinical signs of any type of sinusitis usually
include unilateral purulent nasal discharge, ipsilateral
submandibular lymph node enlargement, and epiphora.
Less common signs include facial swelling, exophthalmos,
abnormal respiratory noises, head shaking, and exercise
intolerance (Lane 1993, Tremaine & Dixon 2001a).
nosa, Bacteroides spp., Peptostreptococcus spp. (Ruggles et al
1993, Tremaine & Dixon 2001a), Streptococcus equi var. equi
(Mansmann & Wheat 1973), and Escherichia coli (Mason
1975a, Schumacher et al 1987), although as noted, the
etiologic importance of these isolates is often unclear.
Nasal endoscopy of horses with sinusitis usually reveals
purulent exudate in the caudal nasal cavity draining from
the nasomaxillary ostia of the rostral and/or caudal maxillary sinuses (“drainage angle”) (Fig. 26.1). Marked accumulation of exudate in the ventral conchal sinus can result
in swelling of the ventral concha, which may eventually
prevent passage of the endoscope up the affected nasal
cavity. Displacement of the nasal septum can occur in
cases with gross distension of this sinus. Straight lateral
radiographs of horses with primary sinusitis frequently
reveal multiple fluid lines in some of the paranasal sinuses.
Oblique radiographs are necessary to separate the left
and right rows of maxillary cheek teeth for radiographic
Primary Sinus Empyema
(Primary Sinusitis)
Primary sinusitis is the result of obstruction of the normal
nasomaxillary drainage with resulting accumulation of
mucus in the sinus, which later becomes infected. Some
cases occur following upper respiratory tract infections
that cause inflammation, increase mucus production
within the sinuses, and decrease drainage of secretions
from the sinuses into the nasal cavity via the anatomically
narrow nasomaxillary ostia. The nasal discharge in
primary sinusitis is traditionally stated to be purulent
and odorless (Mason 1975a), but malodorous nasal discharges can occur with primary sinusitis (Tremaine &
Dixon 2001a), especially in association with inspissation
of purulent material in the ventral conchal sinuses
(Schumacher et al 1987).
Culture of exudates from primary sinusitis cases often
yields a mixed bacterial growth that is of unclear etiologic
significance. Isolated bacteria include Streptococcus equi
var. zooepidemicus (Schumacher et al 1987, Ruggles et al
1993), Corynebacterium spp., (Schumacher & Crossland
1994), Staphylococcus spp. (Mason 1975a, Schumacher
et al 1987, Tremaine & Dixon 2001a), Pseudomonas aerugi-
Fig. 26.1. Endoscopic view of the caudal aspect of the middle meatus
(“drainage angle”) in a horse with sinusitis down which purulent
exudate from the maxillary sinuses is draining through the nasomaxillary ostia (arrowheads).
393
SECTION 4 : Disorders of the Upper Respiratory Tract
394
26 Disorders of the Paranasal Sinuses
5
6
RMS
1
VM
7
2
3
Fig. 26.3. Transverse section of the skull of an aged horse at the level
of the fourth cheek tooth (109, 209) showing the voluminous rostral
maxillary sinus (RMS) and the ventral nasal meatus (VM).
9
4
8
Fig. 26.2. Front view of a transverse section of the right paranasal
sinuses and nasal passage through tooth 109 at the level of the most
rostral end of a frontonasal bone flap. 1 = frontal sinus; 2 = dorsal
conchal sinus; 3 = rostral maxillary sinus; 4 = ventral conchal sinus;
5 = dorsal meatus; 6 = middle meatus; 7 = nasolacrimal duct;
8 = ventral meatus; 9 = infraorbital nerve in the infraorbital canal.
Arrow points to opening from the rostral maxillary sinus into the
middle meatus. Rectangle is the point of fracture for a frontonasal
bone flap and includes the point of separation from the underlying
reflection of the dorsal nasal concha. The arrowhead is the lateral
edge of the bone flap. Note the reserve dental crown occupies a large
portion of the sinus cavities in this young horse and along with the
infraorbital canal limits access to the sinuses.
examination of the dental apical areas. Dorsoventral
radiographs are particularly useful for demonstrating
distension of, and exudate within, the ventral conchal sinus
(see Chapter 10).
Acute cases of primary sinusitis may spontaneously
resolve or may respond to antimicrobial drug administration, with the organisms commonly isolated frequently
being sensitive to penicillin. Chronic cases of primary
sinusitis (of > 2 months duration) frequently have gross
thickening of the sinus mucosa, which can further restrict
normal nasomaxillary drainage and such cases may only
show a transient improvement to antibiotic treatment
(Tremaine & Dixon 2001a). Treatment by sinus irrigation
may be performed in these cases, via a sutured irrigation tube or Foley catheter placed via a trephine opening
into the frontal or caudal maxillary sinuses (for lavage
of the frontal and caudal maxillary sinuses), or into the
rostral maxillary sinus (for lavage of the rostral maxillary
and ventral conchal sinuses). Such cases may respond to
lavage with 5–10 liters of water, saline or dilute disinfectants such as 0.05% povidine-iodine solution, once to twice
daily for 5–10 days.
Cases with gross thickening of the sinus mucosa, and in
particular cases with accumulations of inspissated pus
in the sinus, may require surgical debridement and possibly
sinonasal fistulation to improve drainage. An outline of
sinus anatomy and surgical approaches is presented in
Figs 26.2–26.4. The frontal, maxillary, and ventral conchal
sinus are all most easily approached via a large nasofrontal
bone-flap osteotomy (Freeman et al 1990) (Figs 26.4 and
26.5) where the bone is preserved or a smaller osteotomy
where the bone is discarded (Figs 26.6–26.9). Even when
radiographs or computed tomographic images demonstrate
that the inflammation mainly involves the maxillary
sinuses, a frontonasal flap is the preferred approach for a
number of reasons (Freeman et al 1990). When the lesion
is in the maxillary sinus, the frontal approach is far enough
from it to allow creation of the flap without disturbing the
lesion (e.g. sinus cyst), and yet close enough to allow its
easy removal. It also provides a sufficiently clear view of
the sinus interior to allow complete examination.
The incisions necessary for this type of flap do not
involve muscles or large blood vessels, and the size and
position of the flap can be designed to suit the lesion, even
SECTION 4 : Disorders of the Upper Respiratory Tract
26 Disorders of the Paranasal Sinuses
C
A
4
4
6
5
8
5
7
2
1
6
2
11
3
10
3
9
1
B
5
8
1
2
Fig. 26.4. Approaches to the sinuses through a frontonasal bone flap (broken line in A) and maxillary
bone flap (broken line in B), and (C) expanded dorsal view of sinuses. 1 = rostral maxillary sinus;
2 = caudal maxillary sinus; 3 = ventral conchal sinus; 4 = sphenopalatine sinus; 5 = frontal sinus;
6 = ethmoidal labyrinth; 7 = frontomaxillary opening; 8 = dorsal conchal sinus (5 and 8 combine to form
the conchofrontal sinus); 9 = infraorbital canal; 10 = bony maxillary septum; 11 = caudal bulla of ventral
conchal sinus. Reproduced from Freeman 2003, with permission.
395
SECTION 4 : Disorders of the Upper Respiratory Tract
396
26 Disorders of the Paranasal Sinuses
4
6
5
1
2
3
Fig. 26.5. Interior of the right conchofrontal sinus as viewed through
a frontonasal bone flap in a cadaver specimen. For demonstration
purposes, the entire flap has been removed. The rostral part of the
head is to the left and the lateral margin is uppermost. 1 = reflection of dorsal nasal concha which has retained some of the bony
attachment to the underside of the flap; 2 = dorsal conchal sinus;
3 = ethmoid labyrinth; 4 = caudal maxillary sinus; 5 = medial edge of
the frontomaxillary opening; 6 = caudal bulla of the ventral conchal
sinus. Reproduced from Freeman et al 1990, with permission.
allowing access to the nasal passage if necessary (Freeman
et al 1990). If the bone flap is constructed so that it is
hinged on the dorsal midline, it will lie out of the surgeon’s
way when fully opened. The frontonasal flap can also be
used for repulsion of cheek teeth, but access to 109 and
209 (the fourth maxillary cheek teeth) is limited using
this approach. Alternatively, a caudal maxillary osteotomy
may be used in older (>10 years) horses (Fig. 26.10), but
the reserve crowns of the maxillary cheek teeth limit the
access to the sinuses via this approach in younger animals.
A maxillary approach to the rostral maxillary sinus gives
even more restricted access to the sinus lumen because of
the position of the reserve crowns of the third and fourth
maxillary cheek teeth (Triadan 08s and 09s).
Bone flap osteotomies may be created under general
anesthesia or in the standing sedated horse (Scrutchfield
et al 1994, Quinn et al 2004). After making a rectangular
or curved incision through the skin and periosteum, the
bone flap is created with an oscillating saw, chisel or
Gigli wire; the larger, three-sided bone flap may then be
hinged back on its (fourth) uncut side, to fracture the bone,
whilst retaining the flap’s intact skin, subcutaneous tissue
and periosteal attachments. Alternatively, an axial-based
curvilinear incision may be made and the skin and perioosteum can be reflected. The osteotomy can be created
using a 5-cm diameter trephine with the disc of bone being
discarded (Figs 26.6–26.8). The skin and periosteum are
closed over the osteotomy ensuring that a 5–10-mm shelf
of bone is present peripheral to the osteotomy on which
the periosteum can be laid, to help prevent dehiscence.
Although sequestration of the flap has been cited as a risk
Fig. 26.6. A curvilinear incision has been made through the skin and
periosteum which have then been reflected back, to enable a right-sided
nasofrontal bone osteotomy to be made in a standing sedated horse.
of retention of sinus osteotomy flaps, published reports do
not confirm this to be a frequent occurrence, especially with
larger flaps. Alternatively, despite the loss of a 5-cm disc of
bone, albeit over a flat surface, the cosmetic results after discarding the flap are usually acceptable (Quinn et al 2004).
At sinusotomy, inspissated pus and grossly thickened
mucosa are removed and the sinus can then be irrigated
postoperatively (Fig, 26.9). If sinonasal drainage appears
to be compromised, it may be improved by creation of a
fistula through the dorsomedial wall of the ventral concha
into the nasal cavity. Even when performed on the less
vascular, dorsal aspect of the medial conchal wall, this
fistulation will usually be accompanied by profuse hemorrhage. To control hemorrhage after such fistulation a
3-inch (7.6-cm) elasticated stockinet can be introduced
into the sinus via the nasal cavity (Fig. 26.11). To place
this packing, an assistant passes a Chambers’ mare
catheter up the nasal passage until it can be digitally
directed into the sinus by the surgeon. A length of
umbilical tape is tied to the end of the catheter in the sinus
and this end is drawn out of the nostril while the other
remains within the sinus. Then saline-soaked gauze
SECTION 4 : Disorders of the Upper Respiratory Tract
26 Disorders of the Paranasal Sinuses
Fig. 26.7. A large (5-cm) diameter trephine is being used to create a large bone flap into the left frontal
sinus in this horse, enabling surgical access to the dorsal conchal, frontal and caudal maxillary sinuses. The
bone flap is discarded and the flap later closed by apposing the skin and periosteum.
Fig. 26.8. Copious quantities of purulent exudate flowing from a nasofrontal bone flap osteotomy in a
horse with chronic sinus empyema.
397
SECTION 4 : Disorders of the Upper Respiratory Tract
398
26 Disorders of the Paranasal Sinuses
Fig. 26.9. The skin flap and periosteum are supported by a rim of
frontal bone and are apposed using interrupted sutures (arrowheads).
A maxillary trephine opening has then been made to allow postoperative irrigation of the maxillary sinuses through a Foley catheter.
BF
Fig. 26.10. A large maxillary bone flap (BF) has been created in this
horse using an oscillating bone saw. This approach gives exposure to
the caudal and rostral maxillary sinuses. The ventral conchal sinus
is variably accessible dorsal to the infraorbital canal. This horse has
extensive, inflamed soft tissue swelling within its caudal maxillary
sinus.
Fig. 26.11. Diagram outlining the postsurgical packing of a paranasal
sinus to reduce hemorrhage following sinonasal fistulation.
SECTION 4 : Disorders of the Upper Respiratory Tract
26 Disorders of the Paranasal Sinuses
bandage is placed within the “sock” of stockinet in
accordion-fashion until the sinuses are packed.
The umbilical tape is tied around the redundant portion
of stockinet, and the gauze within it, and used to draw
them through the nostrils. The free end of stockinet, and
gauze within it, are sutured to the roof of the false nostril
with a heavy mattress suture over a butterfly of gauze
sponge, and any excess packing is trimmed flush with the
nostril. Alternatively, packing can be brought out through
a trephine hole in adjacent intact bone. The purpose of the
stockinet “sock” is to prevent migration of the packing into
the pharynx, where it can be swallowed. It has been
suggested that the upright position of the head when
the procedure is performed in the standing horse results in
less bleeding, although profuse hemorrhage can accompany fistulation of the venous conchal sinuses in standing horses. The necessity and efficacy of this sinonasal
fistulation has been questioned (J. Schumacher, personal
communication) and it is possible that sinonasal fistulation
could alter mucociliary clearance and diminish intrasinus
retention of endogenous (possibly bactericidal) nitric oxide.
The bone flap is replaced in situ (if retained) and may be
secured with one or two wire sutures inserted into preplaced drill holes in the flap and adjacent bone, although
this may be unnecessary. The periosteum is closed with
absorbable sutures and the skin is closed with staples or
non-absorbable sutures. A lavage cannula or Foley catheter
sutured into a separate trephine opening in the frontal
sinus or caudal maxillary sinus allows postoperative
irrigation of the sinuses. The prognosis for resolution of
chronic sinusitis, including cases involving the ventral
conchal sinus after surgical debridement, and where
necessary, creation of sinonasal drainage is excellent
(Tremaine et al 2001b, Quinn et al 2004).
Dental Sinusitis
Sinusitis commonly occurs with apical infections of the
caudal maxillary cheek teeth (Triadan upper 08s–11s)
(Mason 1975a, van der Velden & Verzijlenberg 1984,
Lane 1993) and such dental infections caused 53% of
sinusitis cases in one study (Tremaine & Dixon 2001a).
Dental sinusitis occurs most frequently in horses aged
4–7 years (Dixon et al 2000b). Maxillary cheek teeth apical
infections commonly occur following anachoresis (bloodborne infections of apices) (Dacre 2004) but also occur
secondarily to idiopathic dental fractures (lateral slab or
saggital), or with severe diastemata, and sometimes in
conjunction with supernumerary cheek teeth (Dixon et al
1999, 2000a, Dacre 2004). Nasal discharge is frequently
fetid when associated with dental secondary sinusitis,
and also with intranasal tracts and granulomas resulting from infection of the first or second (or occasionally
third) maxillary cheek tooth (Triadan 106–108, 206–208)
(Lane 1994). Anaerobes including Bacteroides fragilis,
399
Fig. 26.12. Computed tomography transverse image of skull of a
young horse at the level of the rostral maxillary sinuses, showing
unilateral distortion of the overlying maxillary and nasal bones caused
by an expansive soft tissue density mass within the sinus. Reproduced
with the permission of Dr Wolfgang Henninger, University of Veterinary
Medicine, Vienna.
B. melaninogenicus, B. oralis and Fusobacterium mortiferum
have been cultured from nasal discharge with such infections (Mackintosh & Colles 1987), but their precise
etiologic role remains unclear.
Radiography is an insensitive technique for detection
of dental infections, especially in younger horses, because
the radiographic changes associated with anatomical
development of cheek teeth apices (i.e. blunt apices,
absence of roots, wide periodontal spaces and absence of
lamina dura denta in this region) are similar to the
radiographic signs of early apical infection (see Chapter 10).
In such cases, the presence of apical infection can sometimes be confirmed by gamma scintigraphy, which is more
sensitive than radiography in selected cases, particularly in
the early stages of the disease (Weller et al 2001) (see
Chapter 12). Computed tomography and magnetic resonance imaging are also increasingly used to obtain highly
detailed images of structures within the equine head and
thus make an early and accurate diagnosis of apical infections (Tiejte at al 1998, Morrow et al 2000, Henninger
et al 2003) (Fig. 26.12).
Sinusitis secondary to maxillary dental apical infections
usually necessitates removal of the affected cheek tooth
before resolution of the sinusitis will occur. Because of
difficulty with the extraction of cheek teeth and the major
long-term consequences following such extractions, this
procedure should never be undertaken lightly. Definite
SECTION 4 : Disorders of the Upper Respiratory Tract
400
26 Disorders of the Paranasal Sinuses
diagnosis of dental involvement in sinusitis using radiography, scintigraphy or computed tomography is essential
before embarking on tooth removal. Anecdotal reports
suggesting that endodontic therapy of infected pulp per os,
effectively sealing the oral cavity from the sinus, will result
in resolution of the sinus (T. Johnson, personal communication) have not been critically evaluated.
Infected cheek teeth may be removed via oral extraction,
repulsion or via a lateral buccotomy. The latter technique can be used for the rostral three maxillary cheek
teeth but not for the caudal maxillary cheek teeth.
Extraction per os is associated with considerably reduced
complications compared to repulsion, and additionally,
may be accomplished in the standing horse (Tremaine
2004b, Dixon et al 2005). Dental extractions involving the
maxillary cheek teeth that cannot be achieved by oral
extraction (e.g. badly fractured or carious cheek teeth) can
be performed under general anesthesia via a bone-flap
osteotomy or via trephine opening. Intraoperative imaging to ensure accurate alignment of the punch with the
affected tooth before repulsing the tooth is advised, to avoid
iatrogenic damage to adjacent structures.
If dental extraction is performed per os in horses with
dental sinusitis, lavage of the affected paranasal sinuses
should also be performed post extraction. Intraoperative
radiographs should be taken after dental removal (especially by repulsion) to attempt to identify the possible
presence of intraalveolar bone or dental fracture fragments that are likely to sequestrate. Following oral extraction the alveolus can be temporarily packed with an
antibiotic-soaked swab (Dixon et al 2005), but following
repulsion a more robust alveolar packing is required,
such as an acrylic plug attached to adjacent cheek teeth,
to prevent the development of an oromaxillary fistula.
Unsuccessful treatment of sinusitis can be attributed to
oromaxillary fistula, persistent alveolar osteitis, abscesses
within the overlying sinus, failure to remove all the infected
tooth and infected or loose alveolar bone, and failure to
treat obligate anaerobes with appropriate antibiotics such
as metronidazole (De Moor & Verschooten 1982, Mackintosh
& Colles 1987). The presence of small alveolar sequestra,
which are not identifiable on postoperative radiographs,
are an occasional cause for persistent clinical signs of
sinusitis. These apparently develop later as the result of
damage to alveoli by the repulsion process. The long-term
prognosis for both primary and dental sinusitis cases is
good (Tremaine & Dixon 2001b).
et al (1992), Aspergillus fumigatus was cultured from six,
Pseudallescheria boydii from one, and Penicillium spp. from
a single case. Pseudallescheria boydii, an opportunistic
saprophyte, has also been isolated from a frontal sinus
lesion (Johnson et al 1975).
Aspergillus fumigatus is ubiquitous in dead vegetation
including hay and straw. The mechanism of infection of
the nasal chambers or paranasal sinuses of horses by
normally saprophytic fungi is not clear, but previous
trauma from surgery or nasogastric tube passage may be a
factor in some cases (Watt 1970, Greet 1981, Tremaine &
Dixon 2001b).
Mycotic sinonasal infections caused by other fungal
organisms are common in warm humid climates. These
have involved infection with Cryptococcus neoformans (Watt
1970, Corrier et al 1984), Coccidioides immitis (DeMartini &
Riddle 1969, Hodgkin et al 1984), Rhinosporidium seeberi
(Myers et al 1964), Conidiobolus coronatus (Entomophthora
coronata) (Bridges et al 1962, Hanselka 1977, Zamos et al
1996), Conidiobolus lamprauges (Humber et al 1989) and
Hyphomyces destruens (Hutchins & Johnston 1972). Such
mycotic granulomas are characterized by the presence of
necrotic foci or “kunkers” within proliferative granulation
tissue. Nasal infections by these lesions are described in
detail in Chapter 25.
Sinus mycosis has also been reported secondary to other
intrasinus lesions such as progressive ethmoidal hematoma
and can also occur following sinus surgery for other diseases such as progressive ethmoidal hematoma, sinus cysts
or following head trauma (McGorum & Dixon 1992,
Tremaine & Dixon 2001a).
Mycotic sinus infections commonly cause a unilateral
nasal discharge, which may vary from mucopurulent,
purulent to sanguineous, and is frequently malodorous
(McGorum et al 1992, Tremaine & Dixon 2001a).
The treatment of superficial mycotic lesions with antimycotic drugs including nystatin (Campbell & Peyton
1984), enilconazole or natamycin (McGorum et al 1992)
by topical application directly or via an endoscope carries a
good prognosis although recurrence is possible. Surgical
removal of large intrasinus fungal granulomas or plaques
or of any underlying cause such as sequestra, cysts or progressive ethmoidal hematoma lesions, followed by sinus
irrigation with a topical antifungal such as natamycin or
miconazole, usually results in rapid resolution of the lesions.
Mycotic Sinusitis
Halicephalobus gingivalis is a saprophytic nematode found in
decaying humus and infection through an unknown route
can involve the sinuses, central nervous system, and, to a
lesser extent, the kidney in certain geographical regions
(Pearce at al 2001). Infection of the sinuses produces a
mass of gray–yellow fibrous tissue that obliterates the
sinuses and their walls, loosens teeth and distorts sinus
Equine sinonasal diseases associated with fungal infection
are rare in the horse in the UK. Greet (1981) first described
three cases of mycotic rhinitis in horses caused by
Aspergillus fumigatus, and subsequent reports are sparse.
Of ten cases of sinonasal mycosis described by McGorum
Halicephalobus gingivalis Infection
SECTION 4 : Disorders of the Upper Respiratory Tract
26 Disorders of the Paranasal Sinuses
architecture. Infection can be unilateral or bilateral, can
involve both the upper and lower jaws, and can spread
from there to the kidneys and cerebellum (Freeman 1991a).
Predominant clinical signs of H. gingivalis infection
are facial distortion with firm swellings in the maxilla,
unilateral or bilateral nasal discharge, marked dyspnea and
stridor, difficulty in eating, and weight loss (Pearce et al
2001). The condition can be confused with squamous cell
carcinoma but the female rhabditiform nematodes and
their larvae and eggs can be seen in clusters or scattered
throughout a biopsy specimen. Surgical debulking, intraoperative lavage with ivermectin, and subsequent oral
ivermectin was successful in one horse with a periorbital
granuloma (Freeman 1991a). However, the response to
ivermectin is not always favorable and the prognosis
appears to be poor, especially because of risk of spread to
other organs.
Sinus Cysts
Sinus cysts are expansive fluid-filled space-occupying
lesions which develop within the sinuses (Leyland & Baker
1975, Dixon 1985, Lane et al 1987) of young to old
horses. Congenital intrasinus cysts have also been reported
(Sanders-Shamis & Robertson 1987, Beard et al 1990).
Equine sinus cysts most commonly occur in the maxillary
sinuses but they can also occur in the other sinuses.
The etiology of these lesions is unclear and no breed or
sex predisposition has been identified. It has been suggested
that they are developmental in origin (Beard et al 1990),
or associated with dental tissues (Boulton 1985), but
little evidence for this theory has been found, although
one case described by Dixon (1985) was attached to dental
alveoli. A common etiology between these lesions and
ethmoid hematomas has been suggested (Lane et al 1987)
as both lesions histologically contain areas of hemorrhage
and hemosiderophages, but little factual evidence for this
association has been found (Tremaine et al 1999). Sinus
cysts are frequently associated with a nasal discharge and
facial swelling (Fig. 26.13). The nasal discharge varies from
mucoid, mucopurulent to purulent, and is thought to be
the result of sinus infection secondary to obstruction of
normal sinonasal drainage. A consistent clinical feature
caused by the expansive nature of sinus cysts is distortion
of the frontal, maxillary, and conchal bones (Lane et al
1987, Caron 1991, Freeman 1991b, Tremaine & Dixon
2001a). This may result in gross facial swelling and
exophthalmos as a result of thinning of the overlying
maxillary or frontal bones, and nasal obstruction as a
result of the expansion of the lesion within the sinuses and
conchae. Horses are affected unilaterally in almost all
cases, but expansion of a frontal sinus cyst with lysis of the
intersinus septum and expansion into the contralateral
frontal sinus, resulting in bilateral clinical signs, can occur
(H. Tremaine, personal observations). Large maxillary
401
sinus cysts can expand into the nasal cavity, causing
compression of the nasal septum and bilateral nasal airflow obstruction.
Diagnosis of sinus cysts is assisted by endoscopy, which
may reveal distortion of nasal conchae. Radiographic
features of sinus cysts include the presence of a rounded,
expansive, soft tissue density lesion in the frontal or maxillary sinuses. Distortion and thinning of the surrounding
bones may be evident as the lesion increases in size, and
secondary distortion of adjacent dental apices within
the sinuses may be present. The contents of the cysts frequently appear radiographically as a homogeneous soft
tissue density shadow. The radiodense capsule may contain
spicules of mineralized tissue (Fig. 26.14) and extralesional
fluid lines may be present if secondary sinus empyema is
present (Tremaine & Dixon 2001a). Centesis of the lesion
via needle aspiration (e.g. using a 16-gauge needle inserted
into areas of thinned, swollen bone) or via a sinusotomy is
diagnostic, yielding a viscous, usually sterile, translucent
yellow fluid which is odorless and may contain some
leukocytes (Dixon 1985, Lane et al 1987, Tremaine &
Dixon 2001a, Beard & Hardy 2003). Treatment of the
Fig. 26.13. The large swelling of the left side of this 8-year-old horse’s
rostral maxillary area (arrows) is the result of bone remodeling in
response to an expanding cyst within the maxillary sinuses.
SECTION 4 : Disorders of the Upper Respiratory Tract
402
26 Disorders of the Paranasal Sinuses
lesion by surgical drainage may be effective in some cases
(O’Connor 1930, Dixon 1985, Lane et al 1987) but total
removal of the lesion via a nasofrontal or maxillary
osteotomy approach, under general anesthesia or standing
chemical restraint, is the treatment of choice (Fig. 26.15)
(Dixon 1985, Lane et al 1987, Tremaine & Dixon 2001b).
Histologic examination of sinus cysts has revealed
extensive resorption and remodeling of the bones surrounding the cyst, replacement of the normal bony septa
within the sinus by fibrous tissue, and replacement of the
loose intrasinus connective tissue with bony spicules
(Tremaine et al 1999). The cysts themselves are lined by
ciliated columnar respiratory epithelium with focal areas
of ulceration, areas of submucosal calcification and of
subepithelial hemorrhage, and chronic inflammation may
be present (Lane et al 1987, Tremaine et al 1999).
Progressive Ethmoidal Hematoma
Fig. 26.14. Radiograph showing distortion of the sinuses as the result
of a sinus cyst with an increased soft tissue density radio-opacity
(arrows) throughout the sinus.
Progressive ethmoidal hematomas are observed most
commonly in the nasal cavity arising from the ethmoturbinates. Less commonly, lesions arise in the frontal
or maxillary sinuses. The etiology, clinical signs, and
treatment of these lesions are discussed in Chapter 27.
Cases with clinical signs typical of progressive ethmoidal
hematoma (i.e. low-grade chronic, unilateral epistaxis)
and with endoscopic evidence of drainage of small volumes
of blood from the sinonasal drainage areas and which do
not reveal a lesion in the nasal cavities should be subjected
to careful examination of the sinuses by radiography,
sinoscopy or sinusotomy (Fig. 26.16).
Fig. 26.15. Frontal sinus bone flap osteotomy
showing a partially removed sinus cyst wall
(yellow arrows) with a residual pool of honeycolored exudates (blue arrow) typical of this
type of lesion.
SECTION 4 : Disorders of the Upper Respiratory Tract
26 Disorders of the Paranasal Sinuses
403
Neoplasia of the nasal and paranasal sinuses is a relatively
rare condition in the horse (Cotchin 1956, Madewell et al
1976, Sundbergh et al 1977, Priester & Mackay 1980) and
there are only a few multiple case studies of equine sinus
neoplasia (Cotchin 1967, Madewell et al 1976, Stunzi &
Hauser 1976, Hilbert et al 1988, Dixon & Head 1999).
Although the sinuses are lined by ciliated respiratory
mucosa, squamous cell carcinomas are probably the most
common sinus neoplasia (Head & Dixon 1999). These
lesions are usually direct extensions of lesions originating
in the oral cavity (usually the lateral aspects of the hard
palate) or from metaplastic epithelium within the sinuses
themselves (Reynolds et al 1979, Hill et al 1989, Head &
Dixon 1999). They display rapid local expansion and
induce considerable necrosis of adjacent tissue.
Other tumor types recorded with paranasal sinus
involvement include spindle cell sarcoma, mastocytomas,
hemangiosarcoma, angiosarcoma and lymphosarcoma
(Lane 1985, Adams et al 1988, Richardson et al 1994,
Malikides et al 1996, Dixon & Head 1999).
A group of fibro-osseous lesions, often of overlapping
histologic classification, have been reported in the paranasal sinuses of horses. These include osteomas, which
have been found in the frontal and maxillary sinuses
(Gorlin et al 1963, Schumacher et al 1988, Dixon & Head
1999), osteochondromas (Adair et al 1994), fibromas
(Barber et al 1983) and fibrosarcomas (Hultgren et al
1987, Dixon & Head 1999). Tumors of dental tissue origin
with involvement of the maxillary sinuses have been
reported, although such neoplasms more frequently
affect the mandibular or rostral maxillary cheek teeth
(Pirie & Dixon 1993) and such lesions, although more
common in older animals, have been described in foals
(Roberts et al 1978).
Clinical signs associated with neoplasia are similar to
those of other expansive lesions affecting the paranasal
sinuses and include nasal discharge (purulent or mucopurulent, occasionally hemorrhagic), facial swelling (Fig.
26.17), epiphora, and nasal obstruction. However, as a
consequence of the large space into which sinus lesions
can expand, facial swelling and other signs may be absent
until an advanced stage. Head shaking, exophthalmos, and
Fig. 26.16. Nasofrontal sinus bone flap surgery showing an intrasinus
progressive ethmoidal hematoma (arrows), which was not detectable
on nasal endoscopy and which is covered by inspissated pus.
Fig. 26.17. This pony has a rapidly expanding maxillary tumor, which
caused loosening and secondary apical infections of the adjacent
maxillary cheek teeth.
Sinus Neoplasia
SECTION 4 : Disorders of the Upper Respiratory Tract
404
26 Disorders of the Paranasal Sinuses
epistaxis are less commonly observed (Hill et al 1989,
Tremaine & Dixon 2001a).
The diagnosis of intrasinus neoplasia requires, as
for other sinus lesions, clinical and oral examination,
radiography, sinoscopy, and possibly scintigraphy and
computed tomography. Wherever possible, histopathology
of biopsy specimens should be performed to confirm the
diagnosis and help establish a prognosis.
Surgical resection of benign lesions, such as osteomas,
via a nasofrontal flap, may carry a good long-term
prognosis (Schumacher et al 1988, Head & Dixon 1999,
Tremaine & Dixon 2001b). However, the aggressive nature
and the complex anatomical location of most sinonasal
tumors usually prevent complete resection and consequently, a poor prognosis is present following surgical
treatment of these lesions (Dixon & Head 1999). Exceptions include osteomas which are usually amenable to
treatment because they are benign (some may not even
be true neoplasms but hamartomas), grow slowly, have
pedunculated or sessile attachments over a small base, and
tend to form well-circumscribed lesions rather than
infiltrate (Freeman 1991b).
Beta-radiotherapy with cobalt-60 has been attempted
with limited success for soft tissue sinus neoplasms. In one
report, the results of aggressive radiotherapy of advanced
squamous cell carcinomas in three horses was encouraging, because radiation-induced complications were
mild, and survival duration and quality of life were good
(Walker et al 1998).
Traumatic Injuries of the
Paranasal Sinuses
Fractures involving the premaxilla are common in foals
(Hardy 1991) and depression fractures of the frontal and
maxillary sinuses have been commonly reported in
adult horses (Sullins & Turner 1982, Tremaine & Dixon
2001a). Traumatic hemorrhage into the sinuses may
lead to a profuse short-term epistaxis, which is often
followed by an unexpectedly prolonged (> 4 weeks) intermittent low-grade epistaxis. Open sinus fractures frequently lead to secondary sinusitis (Dixon 1993a), and the
presence of intrasinus sequestra may result in chronic
suppuration with persistent sinusitis (Lane 1993). Repair of
these fractures is possible by elevating the depressed
bone flap (Fig. 26.18) and, if it is unstable once elevated,
immobilizing it in the reduced position with stainless steel
wires. To facilitate elevation of the fracture fragments,
holes can be drilled in adjacent undamaged bone and
a periosteal elevator, Steinmann pins, or Langenbeck
retractors can be passed through these to pry up depressed
fragments. If the elevated fragments wedge firmly together
in their normal position and form a stable union it may
be unnecessary to wire them (Turner 1979), but large
Fig. 26.18. This figure shows a horse with a large depressed maxillary
fracture (arrow on fixed side of depressed fracture) undergoing
surgical repair of this injury. Fractured bones such as this can be
elevated and stabilized with wire with a good cosmetic outcome.
fragments should be wired to stable adjacent bone. The
fracture fragments can also be exposed through a large
curvilinear skin flap, especially if an open fracture is
present and intrasinus access is required. Blood clots and
loose bone fragments are removed and the sinus cavity is
flushed liberally with saline. All small fragments without
full periosteal attachments should also be removed. Following repair of the bone and skin wounds, the head should be
bandaged so as to cover the wound, if possible, and the
horse should be recovered from general anesthesia either
with assistance or wearing a padded headguard. Healing
after repair of sinus injuries is usually excellent, particularly if the skin remains intact (Tremaine 2004b) although
suture exostoses may remain.
In horses with long-standing, healed depression fractures, fluorocarbon polymer and carbon fiber can be used
to restore the facial contour (Valdez & Rook 1981), or the
healed maligned areas can be cut with a bone saw, elevated
and then wired into a more anatomically normal position.
However, a better cosmetic appearance can be obtained by
primary open reduction of such large depressed factures
shortly after injury, rather than by facial reconstruction
later. If severe or open sinus fractures are not treated,
complications such as sinusitis, sequestra formation, facial
deformity, abnormal bone growth in young horses, and
nasal obstruction can be expected.
Nasofrontal Suture Exostoses
Swellings of the nasofrontal region of the head as a result
of periostitis of the suture lines between the nasal and
frontal bones, and more rarely the nasal, lacrimal,
SECTION 4 : Disorders of the Upper Respiratory Tract
26 Disorders of the Paranasal Sinuses
and malar bones have been described (Gibbs & Lane 1987,
Speirs 1992, Trotter 1993, Tremaine & Dixon 2001a).
They occur in many breeds but the incidence appears
to be particularly high in thoroughbreds and thoroughbred crosses (Dixon 1991). Although most are possibly
traumatic in origin, including following sinonasal surgery,
especially after a large nasofrontal osteotomy, the exact
etiology of such lesions remains unknown in other cases.
Affected horses present with bilateral, firm, non-painful
swellings, rostral to the eye, accompanied by epiphora
in some cases. Differentiation from facial fractures and
sinusitis is usually possible clinically and radiologically.
Radiographs frequently demonstrate proliferative periosteal changes of the widened and incompletely closed
suture line. The swellings usually remodel and regress
gradually without treatment, but in some cases continued
instability has resulted in progressive increases in the size of
these swellings.
Miscellaneous Sinus Disorders
Frontal sinus eversion is probably a congenital defect that
forms a hard, slow-growing protuberance over, and communicating with, the frontal sinus (Martin & McIlwraith
1981). The bony protuberance can be removed through a
large elliptical incision and the resulting defect in the
frontal bone can be repaired with synthetic polypropylene
mesh (Marlex) and skin.
Osteodystrophia fibrosa or secondary nutritional hyperparathyroidism can develop in horses on a high phosphorus
diet, such as bran, or on some tropical grasses (Clarke et al
1996) and can be attributed to relative calcium deficiency
(Freeman 1991b). It is rare under modern management conditions. Conchal necrosis (De Moor & Verschooten 1982)
may be caused by advanced mycotic rhinitis (Tremaine &
Dixon 2001b) that usually responds to removal of the
affected concha by intranasal curettage and lavage.
The reserve tooth crowns of young (2- to 4-year-old)
Welsh and miniature ponies and other smaller pony breeds
can project a considerable distance into the nasal and sinus
cavities and cause firm, painless, bilateral swellings in the
maxillary bones that should not be confused with injuries
or disease. Facial lumps or “horns” can be seen in horses as
symmetrical painless prominences of the nasal and frontal
bones and possibly are caused by an embryologic fault.
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IN-DEPTH:
RESPIRATORY
Diagnostic and Therapeutic Procedures for the
Upper Respiratory Tract
J. Brett Woodie, DVM, MS, Diplomate ACVS
The techniques that are described below can be performed by the practitioner in the field. Some
specialized equipment is necessary, but being able to perform these procedures will allow the
veterinarian to provide better care for their patient. Author’s address: Rood & Riddle Equine
Hospital, PO Box 12070, Lexington, KY 40580-2070; e-mail: [email protected] © 2011
AAEP.
1.
Introduction
Intralesional formalin can be used to treat a progressive ethmoid hematoma (PEH).1 A practitioner with an endoscope can perform this procedure.
Mila International makes an injection apparatus
that is used transendoscopically.a It is passed
through the biopsy channel of the endoscope and
used to inject formalin into the mass. The diameter
of the injection tubing is 2.5 mm and will easily pass
through the standard biopsy channel, which is 2.8
mm in diameter. However, the biopsy channel on
some endoscopes is less than 2.5 mm in diameter, so
it is important to check this before placing an order.
The length of the injection tubing is 190 cm. The
injection needle on the device from Mila International is 17 gauge. There are endoscopic sclerotherapy needles that are available from other
companies, but the size and length of the injection
needle is very small. An injection apparatus can be
made by using polyethylene tubing (PE) and a needle. To do this, the hub of the needle is severed off
and the “lance” is inserted into the appropriate-sized
PE tubing; however, the injection apparatus cannot be withdrawn through the biopsy channel—it
will get stuck. My advice is to purchase the commercially available product.
After examination of the horse and determination
that injection is necessary, it is best to sedate the
horse for the treatment. Before passing the endoscope, it is best to have the formalin drawn up in a
Luer lock syringe. The volume of 10% formalin (4%
formaldehyde) that is required will depend on the
size of the mass. Start with 20 cc unless the mass
is very small. Drape a towel over the noseband of
the halter so that if the horse snorts during or after
the injection then the formalin will not be blown in
anyone’s face. Everyone that is helping with the
procedure should wear gloves and protective
eyewear. Once the horse is properly sedated and
restrained, pass the endoscope and insert the needle
into the mass, attach the syringe and inject the
formalin. Fill the mass until the formalin begins to
leak. Once the mass is injected, withdraw the needle and endoscope; it is very common for the horse to
snort. Oftentimes the mass will bleed after injection, but this is self-limiting. Explain to the client
that nasal discharge is to be expected as the formalin is causing the tissue to slough. Typically, the
NOTES
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IN-DEPTH:
RESPIRATORY
injection must be repeated in 2 to 3 weeks. The
number of injections required is highly variable;
therefore it should be explained to the owner that a
series of injections will be necessary, and the number required will depend on how the tissue responds.
Owner compliance is a very important part of the
success with this technique. The owner will need
to be dedicated to multiple treatments. There was
a fatal complication reported in one horse with this
procedure.2 The cribriform plate had been damaged by the ethmoid hematoma and formalin
reached the frontal lobes of the brain, resulting in
death. Damage to the cribriform plate was not evident by endoscopic or radiographic evaluation.
Cross-sectional imaging (CT or MRI) would be required to determine if the progressive ethmoid hematoma has involved the calvarium.
2.
Emergency Tracheotomy
Performing a tracheotomy is most often an emergency procedure to bypass a life-threatening obstruction of the upper respiratory tract.3 Examples
of such conditions include but are not limited to
bilateral arytenoid chondritis, bilateral laryngeal
paralysis, severely enlarged retropharyngeal lymph
nodes (strangles), and guttural pouch tympany.
The degree of respiratory distress will determine the
amount of diagnostic evaluation and preparation
that is indicated before the procedure. There is no
time for clipping, prepping, or the use of local anesthetic in a horse that is cyanotic and near collapse.
Oftentimes a horse will become violent when in severe respiratory distress. If this is the case, then it
is not safe to attempt to perform a tracheotomy until
the horse “passes out.” Once this happens, a tracheotomy must be performed as fast as possible.
Pulmonary edema is likely to develop in a situation
such as this. It is best to avoid these situations if at
all possible by performing a tracheotomy before the
horse deteriorates to this level; if it appears that the
horse needs or will need a tracheotomy, proceed with
surgery. It will be less stressful to the clinician and
the horse if a tracheotomy is performed before the
horse is in a critical state.
Fortunately, the clinician will be able to prepare
the surgical site for the procedure in most instances.
Sedation should be used with caution. It is easiest
to perform the surgery in the standing horse with
the head slightly extended. The location for the
tracheotomy is at the junction of the proximal and
middle thirds of the neck. The trachea is most superficial at this location and easiest to palpate.
The hair should be clipped and the skin prepped.
Local anesthetic is injected on midline to desensitize
the surgical site. A scalpel blade is used to make a
midline incision approximately 8 cm in length.
Sharp dissection is continued on midline to the level
of the tracheal rings. Small vessels are often encountered, and mosquito forceps can be used to provide hemostasis. Once the incision is at the level of
the tracheal rings, the tracheotomy is performed by
6
2011 Ⲑ Vol. 57 Ⲑ AAEP PROCEEDINGS
incising through the ligament between tracheal
rings to enter the tracheal lumen. The incision between the tracheal rings is continued to the right
and left sides for approximately 120 degrees of the
ventral tracheal circumference. Care must be
taken to avoid incising the tracheal rings. An index
finger can be inserted into the tracheal lumen to
facilitate placement of a tracheotomy tube. Tracheotomy tubes can range from commercially available J-tubes, self-retaining metal tubes, or silicone
tubes, to a piece of stomach tube or hose that has
been cut off. It is extremely important when placing the tracheotomy tube to make sure that the tube
is in the lumen of the trachea and has not been
placed subcutaneously. After placement, the tube
should be secured to the neck. Some tubes have an
inflatable cuff, but it is not advisable to inflate the
cuff due to the potential for tracheal mucosal damage caused by pressure necrosis.
After surgery, monitoring of the patency of the
tracheotomy tube is very important. The tube can
become obstructed with a blood clot or mucus, causing dyspnea. The tube should be monitored at least
3 to 4 times per day and changed/cleaned as needed.
The skin surrounding the surgical site should be
cleaned as needed. It is important when monitoring the surgical site to make sure there are no “ventral pockets” where exudate can dissect along tissue
planes. The tracheotomy site will heal within 14 to
21 days after removal of the tracheotomy tube.
3.
Sinocentesis and Sinus Lavage
Sinocentesis is indicated in horses that have fluid
accumulation in the paranasal sinuses. This will
allow the clinician to obtain samples for culture and
cytology. After sample collection, lavage of the sinuses can be performed as well. The primary
means of accessing the sinuses is trephination,
which allows limited access to the paranasal sinuses
but can be used as a procedure for aspiration and
irrigation in the standing, sedated patient. The
paranasal sinuses that can be accessed include the
rostral maxillary sinus, caudal maxillary sinus, and
the frontal sinus. Upper airway endoscopy and radiographs of the skull will aid in selecting the trephination site. Before performing the procedure, the
clinician must be familiar with the local anatomy
and borders of the different paranasal sinuses.
4.
Trephination
Locations for trephination are as follows4: Rostral
maxillary sinus: 50% of the distance from the rostral end of the facial crest to the level of the medial
canthus and 1 cm ventral to a line joining the infraorbital foramen and the medial canthus; caudal
maxillary sinus: 2 cm rostral and 2 cm ventral to
the medial canthus; frontal sinus: 60% of the distance in a lateral direction from midline to the medial canthus.
The horse should be sedated and the trephination
site clip, prepped, and blocked with local anesthetic.
IN-DEPTH:
A No. 15 scalpel blade is held between the thumb
and forefinger, and a stab incision is made through
the skin down to the bone. A Steinmann pin held
in a Jacob’s chuck is used to drill into the sinus.
Approximately 5 mm of the Steinmann pin should
be protruding from the Jacob’s chuck so that deeper
structures will not be injured. Choose an appropriately sized Steinmann pin, based on the purpose of
the procedure. For example, when the paranasal
sinuses are lavaged, the size of the pin must be large
enough to accommodate the fluid delivery system.
Once access has been gained to the sinus, a catheter
can be introduced to aspirate a sample for culture
and cytology. If the material is extremely thick, 20
to 30 mL of sterile saline can be infused and a
sample obtained. The sinus can be lavaged by using sterile saline delivered with a pressure bag.
To do this, an administration set is attached to a
1-liter fluid bag, the end of the fluid administration
set is inserted into the trephination site, and the
fluid is infused with the aid of a pressure bag.
RESPIRATORY
Fluid/mucopurulent material should drain from the
nostril. After lavage, the skin incision can be closed
with a staple or a single suture. Another option is
to secure an indwelling catheter for future lavage.
After surgery, there is minimal after care. The
trephination site should be monitored for the development of cellulitis.
References and Footnote
1. Schumacher J, Yarbrough T, Pascoe J, et al. Transendoscopic chemical ablation of progressive ethmoidal hematomas
in standing horses. Vet Surg 1998;27:175–181.
2. Frees K, Gaughan EM, Lillich JD, et al. Severe complication after administration of formalin for treatment of progressive ethmoidal hematoma in a horse. J Am Vet Med Assoc
2001;219:950 –952.
3. Adams SB, Fessler JF. Atlas of Equine Surgery. Philadelphia:
WB Saunders; 2000:185–188.
4. Nickels FA. Nasal passages. In: Auer, Stick, eds. Equine
Surgery. 2nd edition. Philadelphia: WB Saunders; 1999:
334.
a
Lance-A-Lot, Mila International, Erlanger, KY 41018.
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