Page 83 - BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery, 2nd Edition

Neck and
eline Head,
V
A Manual of Canine and F
Thoracic Surger
BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery
y
BSA
OPERATIVE TECHNIQUE 5.1
VetBooks.ir Lateral ear canal resection

PATIENT PREPARATION
• Clip the side of the face ventrally to the midline, rostrally to the lateral commissure of the eyelid, and for several
centimetres caudal to the palpable ear canal.
• If the tympanic membrane is intact, the ear canal may be flushed with dilute chlorhexidine (0.05%). Because
ototoxicity has been reported with antiseptics, some clinicians recommend using only sterile saline when flushing
the horizontal ear canal, particularly if the tympanic membrane is perforated. Prepare the remainder of the surgical
field with antiseptic solution and scrub.
• Some veterinary surgeons administer antibiotics prophylactically (e.g. cefazolin 22 mg/kg i.v. at induction and again
within 2–6h) if the animal is not already on therapeutic perioperative antibiotics.
PATIENT POSITIONING

Lateral recumbency, with a folded towel under the side of the head. The pinna should be lying over the top of the head,
away from the surgical site.

ASSISTANT
Optional.

ADDITIONAL INSTRUMENTS
Bipolar cautery is useful but not required.

SURGICAL TECHNIQUE
Approach
The skin overlying the vertical ear canal is cut in a U shape, starting at the tragohelicine notch and extending to a point
1–2 cm ventral to the junction between the vertical and horizontal ear canals, then returning to the intertragic incisure.
The ear canal is exposed by dissection through the overlying subcutaneous tissue and retraction of the parotid salivary
gland.

Surgical manipulations
1 Elevate the skin from the underlying ear canal and either remove it or leave it attached dorsally. Elevate the
subcutaneous tissue from the lateral wall of the vertical canal using blunt and sharp dissection until the canal wall
is exposed. The parotid gland may need to be retracted ventrally to expose the annular cartilage completely.
2 After the vertical canal is exposed, make two parallel incisions in the lateral wall to make a ‘drainage board’. If the
incisions are started at the canal opening, position yourself at the dorsum of the dog’s head, looking down the ear
canal. Make small cuts with Mayo scissors, starting at the tragohelicine and intertragic incisures, alternating sides
until the flap extends to a level slightly below the midpoint of the horizontal canal circumference.
Alternatively, make two stab incisions with a No. 11 blade at the ventral-most extent of the proposed flap (at the
junction between the conchal and annular cartilage). Insert a blade of the Mayo scissors into one of the
perforations and extend the cut upwards to the incisure above. Repeat on the other side.

WARNING

Because the ear canal spirals slightly inward as it bends, it is easy to transect the flap accidentally.
Therefore, make small cuts, alternating to either side, and recheck the flap position frequently

3 Grasp the skin flap or its attached cartilage with Allis tissue forceps and complete the lateral wall flap. The base
of the flap should be located on each side of the horizontal canal, slightly below the midpoint of its circumference.
The flap should lie flat, without obstructing the horizontal canal opening.
4 Remove the distal third to half of the lateral cartilage flap so that a 2–3 cm drainage board remains.
Remove additional facial skin as needed so that the flap is pulled ventrally away from the opening.

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