Page 81 - BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery, 2nd Edition

BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery

exposure. The stalk of the polyp, located dorsolaterally on into the horizontal ear canal (Greci et al., 2011). Histo-
digital or instrument palpation, is grasped blindly and pathology of material removed from the middle ear cavity
VetBooks.ir Alternatively, a portion of the polyp can be excised to def nitive diagnosis of cholesteatoma.
via ventral or lateral bulla osteotomy is necessary for
gently with right-angled forceps or Allis tissue forceps.
i
expose the base. It is important not to crush the base of
the polyp with the forceps as it may break off at that site,
leaving tissue remnants attached to the auditory tube or Surgical treatment
bulla lining. Removal of the polyp is accomplished with Middle ear cholesteatoma should be surgically addressed
gentle, continuous traction. If the entire polyp is removed, by ventral bulla osteotomy or TECA with lateral bulla oste-
the stalk of the polyp should appear long and tapered; otomy. As most affected dogs have a chronic history of
on otoscopic evaluation, blood may appear under the OE, TECA with lateral bulla osteotomy is likely to be
tympanic membrane of the affected side. The cat is then the more appropriate surgical approach. Cholesteatoma
placed on an anti-inflammatory dose of glucocorticoids recurrence has been reported following ventral or lateral
(e.g. 1–2 mg/kg q24h) for 2 weeks, after which the drug is bulla osteotomy; the risk of recurrence is greater in dogs
tapered over 14–17 days. with evidence of more advanced disease on initial presen-
tation (e.g. inability to open the mouth, neurological defi-
cits or evidence of bony lysis on CT) (Hardie et al., 2008).
Middle ear cholesteatomas in
dogs Considerations for surgical

A cholesteatoma is an epidermoid cyst composed of success in patients with ear
a keratin core surrounded by a keratinizing stratified
squamous epithelial lining and located within the middle disease
ear cavity. In humans, cholesteatomas can be congenital
Surgery of the ear is most often indicated in patients with
or acquired. In dogs, middle ear cholesteatomas are a history of inflammatory skin disease. In these patients,
thought to be acquired secondary to chronic OE and OM.
control of the underlying inflammatory skin disease is key
The aetiology of middle ear cholesteatomas is not fully to improving comfort and preventing failure of surgical
known, but they are thought to form secondary to invagi- procedures such as aural haematoma repair. Consultation
nation of the tympanic membrane into the middle ear
with a veterinary dermatologist may be necessary to
cavity with subsequent cyst formation, or to migration of address underlying dermatological disease, particularly
stratified squamous epithelium from the ear canal to the
chronic allergic dermatitis. Appropriate patient selection
middle ear cavity through a compromised tympanic mem- for surgical procedures should also be emphasized. For
brane. The progressive accumulation of keratin within the example, failure of lateral ear canal resection is often inev-
cyst can lead to cholesteatoma expansion and destruc-
itable in dogs with end-stage otitis or poorly controlled
tion of surrounding structures, particularly bone (Hardie et inflammatory skin disease. Patients with chronic OE and
al., 2008; Greci et al., 2011). Middle ear cholesteatoma has
OM have frequently been exposed to multiple topical
been reported following TECA and lateral bulla osteotomy and systemic antimicrobials, and antimicrobial-resistant
in two brachycephalic dogs; this may have been due infections, particularly with Staphylococcus spp. or P. aeru -
to the relative difficulty in performing these procedures
ginosa, are common. Appropriate pre- and postsurgical
in brachycephalic breeds and the potential transfer of antimicrobial therapy based on culture and susceptibility
stratified squamous epithelium from the ear canal to the
results is also integral to improved surgical outcomes.
middle ear cavity during surgery (Schuenemann and
Oechtering, 2012).
Clinical signs References and further reading

Clinical signs of middle ear cholesteatomas depend on the Anderson DM, Robinson RK and White RAS (2000) Management of
inflammatory polyps in cats. Veterinary Record 147, 684–687
severity and size of the cystic mass. Longstanding lesions
Bacon NAS (2012) Pinna and external ear canal. In: Veterinary Surgery: Small
may fill and expand the tympanic bulla, with associated Animal, ed. KM Tobias and SA Johnston, pp. 2059–2078. Elsevier, St Louis
bony lysis and clinical signs such as facial nerve paresis or
Bischo MG and neller S ( 4) Diagnostic imaging of the canine and feline
paralysis, vestibular dysfunction, and pain on opening the ear. Veterinary Clinics of North America: Small Animal Practice 34, 437–458
mouth or on palpation of the tympanic bulla and/or tempo- Buback JL, Boothe HW, Carroll GL and Green RW (1996) Comparison of three
romandibular joint (Hardie et al., 2008; Greci et al., 2011). methods for relief of pain after ear canal ablation in dogs. Veterinary Surgery 25,
380–385
Cli ord CA, De orimier P, an M and Garrett D ( 13) Neoplastic and non-
Diagnosis neoplastic tumors. In: Muller & Kirk’s Small Animal Dermatology, 7th edn, ed.
WH Miller, CE Gri n and Campbell, pp. 774 843. Elsevier, St ouis
Middle ear cholesteatoma may be suspected in dogs Cole LK (2012) Primary secretory otitis media in Cavalier King Charles Spaniels.
Veterinary Clinics of North America: Small Animal Practice 42, 1137–1142
presenting with inability or discomfort on opening the
Cole LK, Kwochka KW, Podell M, Hillier A and Smeak DD (2002) Evaluation of
mouth, as well as neurological signs consistent with radiography, otoscopy, pneumotoscopy, impedance audiometry and endoscopy
vestibular and facial nerve dysfunction. CT findings con- for the diagnosis of otitis media in the dog. In: Advances in Veterinary
Dermatology, 4th edn, ed. KL Thoday, CS Foil and R Bond, pp. 49–54. Blackwell
sistent with cholesteatoma include filling and expansion of Science, Oxford
the middle ear cavity by non-contrast-enhancing soft Demirutku A, Ozer K, Devecioglu Y et al. (2012) Pinnal squamous cell carcinoma
tissue opacity material with sclerosis or lysis of the bone of in cats and the e ectiveness of treatment with radical pinnectomy. Veterinarni
Medicina 57, 420–429
the tympanic bulla (Travetti et al., 2010; Greci et al., 2011).
Otoscopic examination may reveal a white or yellow mass Detweiler DA, Johnson LR, Kass PH and Wisner ER (2006) Computed
tomographic evidence of bulla e usion in cats with sinonasal disease: 1
or ‘flakes’ of keratin protruding from the middle ear cavity 2004. Journal of Veterinary Internal Medicine 20, 1080–1084
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