Page 76 - BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery, 2nd Edition

Chapter 5 · Surgery of the ear

by lateral resection. Owners of pets with otitis secondary
to other causes, particularly uncontrolled allergic derma-
VetBooks.ir not curative and that continued local and systemic treat-
titis, should be warned that lateral ear canal resection is
ment will be necessary to control the disease. Lateral ear
canal resection is usually unsuccessful in Cocker Spaniels
with OE, even if surgery is performed before hyperplastic
changes occur, because of disease progression despite
medical treatment.
A thorough physical and dermatological examination
should be performed to evaluate the animal’s health and to
look for evidence of underlying skin disease. The ear canals
should be palpated and examined to verify that they are
not mineralized or proliferative. If OM is suspected, radio-
graphy or CT of the bulla should be performed. OM can
be present without radiographic changes, so a careful
examination of the tympanic membrane under anaesthesia
nd-stage otitis in a Cocker paniel/ iniature oodle
5.5 crossbreed that had undergone lateral wall resection, with is warranted. Cytological assessment of the ear canal
complete blockade of the ear canal opening. The obstructive tissue as should be performed in all cases to guide topical antimicro-
a combination of hyperplastic glandular tissue with associated osseous bial therapy; culture of the deep external ear canal may
metaplasia. also be considered, particularly if the animal has a history
of recurrent or unresolved bacterial infections.
longer have a drainage pathway, and abscessation with Surgical technique: Details of this procedure are given in
fistulous tracts through soft tissues of the head is inevi t- Operative Technique 5.1. If OM is present, a myringotomy
able. In a minority of chronic otitis cases, the horizontal or ventral bulla osteotomy can be performed so that the
portion of the external canal will be deemed salvageable, tympanic bulla can be cultured and gently flushed.
and the surgeon may elect to ablate only the vertical canal.
Conversely, a lateral wall resection may be chosen in Postoperative complications: The most common compli-
cases where both the vertical and horizontal portions cations include dehiscence of the surgery site and pro-
are fairly healthy, but continued episodes of otitis are gression of disease, particularly in patients with an
expected. Lateral wall resections allow for improved air uncontrolled or poorly controlled primary cause of otic
circulation and moisture evaporation and may also inflammation. Dehiscence occurs in about 25% of patients
improve the owner’s ability to medicate the ear. It must be because of self-trauma, tension, infection or poor tech-
stressed, however, that any procedure short of TECA is nique. Extensive flap dehiscence that is not repaired may
subject to failure if the veterinary surgeon is unable to result in stenosis of the new opening. Stenosis can also
prevent or successfully manage continuing episodes of occur with inadequate ventral reflection of the cartilage
otitis and secondary infection. Therefore, the early identifi- flap; this will require revision to prevent canal obstruction
cation of candidates that might benefit from subtotal abla- and subsequent otitis and fistulation. It may be necessary
tive procedures is recommended. occasionally to clip the hair around the opening to improve
A more sound indication for lateral wall resection is the ventilation and drainage.
prophylactic surgical treatment of congenital anatomical
abnormalities, such as infantile stenosis of the external Prognosis: Excellent results are seen in 41–50% of
canals (most commonly seen in the Shar-Pei) and exces- animals treated with lateral ear canal resection, but many
sively hirsute canals (most common in the Standard of these patients will still require continued treatment to
Poodle and some terrier breeds). In either situation, poor prevent recurrence of otitis. Animals that have congenital
aeration and water trapping may result in recurrent OE stenosis of the ear canal without hyperplastic changes
without any underlying inflammatory disease. Improving usually have excellent outcomes. Ear disease will inevit-
the local microclimate of the canals by excising the lateral ably progress in Cocker Spaniels and in cases where the
walls may be the only treatment necessary. underlying cause of otitis has not been controlled, and
many of these animals will require TECA within a few years.
Surgical procedures
Vertical ear canal resection
Lateral ear canal resection
As with lateral resection, vertical ear canal resection alters
Lateral ear canal resection, also known as lateral wall the temperature and humidity of the ear canal environ-
resection or Zepp’s procedure, involves removal of most ment, improves drainage and provides access to the
of the lateral wall of the vertical ear canal and the forma- horizontal ear canal to facilitate application of topical med-
tion of a ventral cartilaginous and epithelial ‘drainage ications. Vertical resection is usually performed to remove
board’. Lateral resections will improve the environment tumours or polyps of the vertical ear canal that cannot
and drainage of the canal and facilitate application of be completely excised with a lateral resection. Vertical
topical medications. They may also be useful for removal resection has also been used in animals with per sistent or
of small benign tumours involving the lateral surface of recurrent OE, as long as the horizontal ear canal is patent.
the vertical ear canal. Vertical resection removes more inflamed tissue, and is
associated with less postoperative discharge and pain,
Preoperative assessment: Appropriate patient selection fewer complications, and better healing and cosmetic
is critical to success; many dogs with severe proliferative appearance than lateral resection, although it can cause
OE will progress despite improvements made to the canal drooping of erect ears.

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