Page 86 - BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery, 2nd Edition

Chapter 5 · Surgery of the ear
y of the ear
Chapter 5 · Surger

OPERATIVE TECHNIQUE 5.2
VetBooks.ir Vertical 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. Clip the entire pinna and include it within the surgical field.
• 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 and Gelpi retractors are useful but not essential.

SURGICAL TECHNIQUE
Approach
Expose the affected ear canal through a lateral T-shaped incision that encircles the vertical canal opening and
extends to a point ventral to the junction between vertical and horizontal ear canals (as for lateral wall resection).
Make the initial skin incision around the opening of the vertical canal and just above the antihelix projection on the
concave portion of the pinna. Use Mayo scissors to extend the skin incision through the cartilage of the medial wall of
the vertical ear canal.
Surgical manipulations
1 Use blunt or sharp dissection with a sponge or scissors to free the vertical canal to the level of the annular
cartilage. To dissect with a sponge, hold the proximal (dorsal) portion of the ear canal with Allis tissue forceps and,
with a gauze sponge, wipe downwards along the canal (similar to stripping the spermatic cord in a castration). This
will remove all the fat and expose the muscular attachments, which can be transected with scissors or cautery.
2 Once the canal is exposed to the junction of the annular and auricular (conchal) cartilage, transect the horizontal
cartilage at least 1 cm beyond any tumour margin. It is advisable to leave a small portion of the vertical canal to
make cartilage flap extensions dorsally and ventrally to reduce postoperative stenosis, although this is not
necessary in all cases.
3 Incise the remaining vertical ear canal cranially and caudally to create both a ventral and a dorsal ‘drainage board’
to reduce postoperative stenosis.

PRACTICAL TIP
The ear canal can be dissected free of soft tissues by stripping it with a gauze sponge. This will expose muscular
attachments that can be transected, with scissors, cautery or a laser, at their insertion sites on the ear canal

WARNING
The facial nerve can occasionally be damaged by vigorous
dissection or retraction ventral or lateral to the horizontal canal

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