8.1 Pinna Lacerations
8.2 Pinnectomy
8.3 Auricular Haematoma Drainage
8.4 Lateral Wall Resection
8.5 Vertical Ear Canal Resection
8.6 Total Ear Canal Ablation with Lateral Bulla Osteotomy
8.7 Subtotal Ear Canal Ablation with Lateral Bulla Osteotomy
8.8 End-To-End Anastomosis
8.9 Ventral Bulla Osteotomy
8.10 Laser Ear Surgery
8.1 PINNA LACERATIONS
Lacerations may require surgical closure if they are full thickness or if they are partial thickness with the epithelium elevated from the cartilage as a two- or three-sided flap. Lacerations can be closed with absorbable or non-absorbable suture.
1. For partial thickness lacerations, close any dead space with a continuous suction drain or with partial thickness mattress sutures that engage epithelium and cartilage. Appose the skin along the laceration with simple interrupted sutures (
Fig. 8.1). If an L-shaped tear is present, place the first suture at the corner of the L to realign the skin.
2. For full thickness lacerations, appose cartilage and skin by realigning the skin with simple interrupted sutures on each side of the pinna, starting at the margin of the ear (
Fig. 8.2), or with simple interrupted sutures on one side and a vertical mattress pattern on the other. Trim excess cartilage if the skin cannot be apposed over the cartilage edge.
3. For lacerations or trauma that results in marginal defects or necrosis, perform a partial pinnectomy (see section 8.2).
4. Large partial thickness wounds near the base of the outer surface of the pinna are debrided and managed open until a healthy granulation bed has formed, then covered with single pedicle advancement flap from the lateral surface of the neck or muzzle or the dorsum of the head.
5. If a large, full thickness section of one pinna margin has been damaged or removed, the pinna can be reconstructed with distant flaps. The margins of the remaining pinna are debrided and a single pedicle flap is elevated from head or neck skin near the wound. The flap is sutured to epithelium along the convex (outer) surface of the pinna, and the ear is bandaged. Bandages are changed as needed. After 2 weeks, the flap is transected from the donor site to approximate the new margin of the pinna. A new flap is elevated along the dorsum of the head and sutured to the wound’s epithelial margin along the concave surface of the ear, putting it in apposition (subcutis to subcutis) with the first flap. The ear is rebandaged. After 2 weeks, the second flap is transected and its margin is sutured to that of the first flap to form the final pinna margin.
8.2 PINNECTOMY
Pinnectomy is commonly performed in cats for resection of squamous cell carcinoma and in dogs for resection of mast cell tumours or removal of damaged pinna margins.
1. Clip and prep the surgical site.
2. Excise the affected tissue with laser, a scalpel blade, or cautery; take 1–2 cm surgical margins for neoplastic tissue. The laser will seal vessels up to 1 mm in diameter.
a. For blade excision of large areas, place a non-crushing (e.g. Doyen) forceps along the proposed margin. Transect along the distal edge of the forceps with the scalpel. Leave the forceps in place for several minutes to provide haemostasis before suturing.
b. For laser excision, use a 0.4 mm tip and set the laser on continuous mode at 8–10 W of power. With the laser, make a partial thickness cut to draw a line along the proposed margin to be resected. Then, starting at one pinna margin, begin the full thickness cut. Have an assistant apply lateral traction, perpendicular to the incision, to the pinna apex to retract the tissues and widen the surgical wound as the pinna is incised. Wipe char from the tissue as it forms; presence of char limits cutting and encourages collateral thermal damage.
3. Suture the medial and lateral skin edges together over the cartilage margin with 3-0 or 4-0 monofilament absorbable or non-absorbable suture in a simple continuous or interrupted pattern (
Fig. 8.3). If bleeding vessels are encountered, seal them with bipolar cautery or ligate them by encircling them and the surrounding tissue with a partial or full thickness mattress suture.
8.3 AURICULAR HAEMATOMA DRAINAGE
Auricular haematomas are best treated early before granulation tissue formation and eventual contraction and fibrosis deform the pinna. Some authors recommend needle drainage (after clipping and aseptic preparation), flushing, and administration of oral glucocorticoids or instillation of a corticosteroid into the hematoma; others prefer more long-term drainage with cannulas, close suction systems, or incision. Incisional drainage may be necessary for chronic hematomas. In any case, the underlying cause of the head shaking or scratching must be identified and treated to prevent recurrence.
8.3.1 Teat Cannula
1. Clip and aseptically prepare the ear.
2. With a number 11 blade, make a small stab incision in the apex of the ear at the dependent portion of the haematoma.
3. Insert a teat cannula through the stab incision and secure with suture.
4. Milk any fluid from the haematoma.
5. Bandage the ear flat against the dorsum of the head or ventrally along the neck or cheek to eliminate dead space. Change bandages as needed.
6. Remove the cannula after 1–2 weeks; leave the ear bandaged for 2 weeks.
8.3.2 Closed-Suction Drain
1. Clip and aseptically prepare the ear.
2. Remove the syringe adaptor end of a large butterfly catheter, and add 2–4 fenestrations to the distal 1.5–2 cm of the tubing (
Fig. 8.4).
3. Insert a gauze sponge into the external ear canal. With a number 11 blade, make a small stab incision in the ventral (proximal) portion of the haematoma. Fluid will immediately drain from the haematoma cavity.
4. Insert the fenestrated end of the butterfly catheter into the hematoma cavity (
Fig. 8.5). Place a purse string suture around the entry site to seal the wound, making it airtight around the tube. Secure the tube in place with a finger trap pattern.
5. Insert the needle end of the butterfly catheter into a vacuum blood tube (
Fig. 8.6). Secure the tube to the animal’s collar.
6. Bandage the ear as needed to eliminate dead space and prevent head shaking.
7. Replace the vacuum tube once it contains 2–3 mL or as needed to restore negative pressure on the drain.
8. Remove the drain after 1 week, then rebandage the ear for another week.
8.3.3 Incisional Drainage
1. Clip and aseptically prepare the ear.
2. Make a skin incision through the medial wall of the pinna into the haematoma cavity. Extend the incision so that it encompasses the entire length of the cavity. Flush the cavity with sterile saline.
3. To obliterate dead space in the haematoma cavity, place full thickness mattress sutures parallel to the vessels along the convex surface of the pinna; avoid penetrating the vessels. Tie sutures to appose skin and cartilage without necrosing underlying tissue (
Fig. 8.7).
4. Place a sterile sponge over the incision site, and bandage the ear over the dorsum of the head or along the face or neck. Keep the ear bandaged for 2 weeks, changing the bandage as needed.
5. An alternative to incisional drainage with a scalpel is fenestration of the skin over the hematoma along concave surface of the pinna by use of a 4 mm skin biopsy punch or with a CO2 laser. Fenestrations are placed about 1 cm apart, and the ear is bandaged for 1–2 weeks until the sites are healed.
8.4 LATERAL WALL RESECTION
Lateral wall resection is primarily used to correct congenital canal stenosis, resect laterally located masses within the vertical ear canal, or improve surgical exposure of deeper masses when video otoscopic equipment is unavailable. It is ineffective for treatment of chronic otitis externa, particularly in canals that are proliferative or calcified, but may improve local environmental factors and ease of topical medication administration. Failure rates are high in Cocker Spaniels, which tend to have progressive otitis externa.
1. Clip lateral portion of face, both sides of pinna, and around the base of the ear for complete clip, particularly if making the drain board by cutting the lateral wall from dorsal to ventral (with this technique, the pinna is usually held in one hand while the incisions are made with the other). Flush the canal with sterile saline and use chlorhexidine for the remainder of the prep.
2. Alternative clip: include only the lateral portion of face and concave surface of pinna, if the lateral canal wall is to be opened with proximal (ventral) to distal (dorsal) cuts (this technique may not require manipulation of the pinna during surgery).
3. Position the animal in lateral recumbency. If the pinna is included within the surgical field, perform a hanging ear preparation of pendulous ears.
4. Make a U-shaped incision down the lateral surface of the face, over the canal, ending 1–2 cm ventral to the level of the horizontal canal (
Fig. 8.8).
a. Start the incision at the level of the tragohelicine (pretragic) notch (see Fig. 1.2).
b. Continue ventrally to a level 1–2 cm ventral to the horizontal canal.
c. Curve the incision back up and finish at the intertragic incisure.
5. Dissect the subcutaneous tissues under the skin flap with scissors, so that the skin flap can be reflected dorsally towards the pinna.
6. Dissect the subcutaneous tissues to expose the lateral wall of the vertical canal (
Fig. 8.9). Retract the parotid gland ventrally as needed.
7. To make a drain board, develop a flap in the lateral wall of the vertical ear canal with two parallel cuts:
Dorsal to ventral cut (full ear preparation):
a. Position yourself facing the dorsum of the dog’s head.
b. Determine the canal direction by inserting a straight blunt probe or long straight haemostats into the external ear canal.
c. Starting at the rostral (tragohelicine) notch, cut the cartilage ventrally 1–1.5 cm with sharp scissors (
Fig. 8.10).
d. Make a similar cut starting at the second notch (intertragic incisure).
e. Continue 1 cm cuts on either side to the level of the horizontal canal, reorienting the scissors to follow the inward spiral of the vertical canal so that the final cuts end at the rostral and caudal midpoints of the horizontal canal.
Ventral to dorsal cut (full or lateral ear prep):
a. Identify the ventral most portion of the lateral wall of the vertical canal.
b. With a number 11 or number 15 blade, make a stab incision in the lateral canal wall at the proposed rostral margin of the flap.
c. Make a stab incision in the lateral canal wall at the proposed caudal margin of the flap.
d. Insert one blade of a Mayo or cartilage scissors into the stab incision and cut the lateral canal wall from ventral to dorsal, toward the intertragic incisure, along the proposed caudal margin of the flap (
Fig. 8.11).
e. Insert one blade of a sharp-sharp scissors into the rostral stab incision and cut the lateral canal wall from ventral to dorsal, toward the tragohelicine notch, along the proposed rostral margin of the flap.
8. Reflect the flap ventrally and evaluate the new ear canal opening to the horizontal canal: the opening should be round, not oval or flat, and the flap should lie flat without obstructing the canal. Make additional cuts so that the flap hinges at the level of the midpoint or ventral 1/3 of the sides of the horizontal canals and the horizontal canal opening is round (
Fig. 8.12).
9. Transect the dorsal (distal) half of the lateral wall flap and remove it and the attached skin.
10. Test the flap length to determine where the skin sutures will be placed.
11. Remove additional skin as needed at the base of the incision so that the flap has mild downward tension when extended ventrally.
12. If the flap of cartilage is thick and will not lie flat, make a hinge.
a. At the point where you want the flap to bend, dissect between the cartilage and epithelial lining with a haemostat.
b. Transect the cartilage, leaving the epithelial lining intact.
c. Lay the flap down; it is acceptable for the transected cartilage ends to overlap.
13. Place a skin suture at each corner of the flap (
Fig. 8.13). For interrupted sutures:
a. Take a bite of skin along the skin margin.
b. Take a bite of epithelial lining. If epithelium is thin, the cartilage can be included in the bite.
c. Tie the suture so that it lies off to the side, with the knot away from the incision.
Alternatively, place a vertical mattress skin suture at each corner of the flap using a ‘near–near–far–far’ bite pattern:
a. Take a bite of skin close to the skin margin opposite the flap, with the needle pointing toward the flap.
b. Grasp the flap with thumb forceps and pass the needle under and out the epithelial lining of the flap.
c. Pass the needle back through the lining and the cartilage of the flap, beyond and under the first bite.
d. Pass the needle under the skin margin opposite the flap and come out farther away from the first skin entrance site, passing directly under the initial suture bite.
e. Tie without excessive tension to appose skin and epithelial lining over the cartilage edge.
14. Next, place a skin suture on each side at the notch where the flap hinges, suturing to the surrounding skin margin.
15. Place the remaining skin sutures along the flap.
16. Close any remaining skin defects along the pinna margins.
8.5 VERTICAL EAR CANAL RESECTION
Vertical ear canal resection is recommended when the horizontal ear canal is normal and disease is limited to the vertical ear canal. When closing the vertical ear canal resection, it is important to make sure that there is minimal tension on the skin-to-pinna portion of the closure. It is helpful to temporarily approximate this portion of the incision to determine whether there is sufficient skin to close. More skin can be recruited by extending the vertical incision ventrally; rarely, advancement flaps are required.
