An 18-year-old 3.77-kg (8.31-lb) castrated male domestic medium-hair cat (cat 1) was evaluated at the surgery service of a veterinary medical hospital because of obstructive soft tissue growths involving the opening of the left external auditory canal. A sample of the tissue was obtained with biopsy for ceps 3 weeks prior to surgery by the patient's primary care veterinarian; histologic examination confirmed the presence of multiple ulcerated ceruminous gland adenomas. The growths were located around the outer perimeter of the vertical ear canal and partially obstructed the canal, contributing to otitis externa. Persistent irritation and bleeding were associated with the ulcerated growths, and the cat periodically scratched at the ear and shook its head. The patient was otherwise in reasonably good health on the basis of preoperative physical examination findings.
Results of hematologic and serum biochemical analyses were within the respective reference ranges. The patient was premedicated with oxymorphone hydrochloridea (0.1 mg/kg [0.045 mg/lb], IM) and midazolam hydrochlorideb (0.2 mg/kg [0.09 mg/lb], IM), followed by induction with alfaxalonec (1.0 mg/kg [0.45 mg/lb], IV). The cat was intubated, and anesthesia was maintained with isofluraned in oxygen. The patient received cefazolin sodiume (20 mg/kg [9.1 mg/lb], IV). Lactated Ringer solutionf was administered IV at a rate of 5.0 mL/kg/h (2.3 mL/lb/h) for the duration of anesthesia.
An otoscope was used to assess the entire left ear canal in the anesthetized cat and to determine the limits of the lesions. The ceruminous gland adenomas were limited to the outer third of the vertical ear canal; the remaining portion of the vertical ear canal and the horizontal ear canal were grossly normal. Both sides of the pinna and the adjacent skin were clipped of fur. The surgical site was prepared with chlorhexidine surgical scrubg alternated with gauze sponges impregnated with sterile saline (0.9% NaCl) solution, and the pinna and adjacent skin were draped.
A No. 15 scalpel blade was used to incise the medial base of the pinnal epithelial surface and underlying cartilage. The incision was then extended around the circumference of the external auditory canal, including resection of the affected skin. Care was taken to avoid trauma to the lateral pinnal vasculature. Metzenbaum scissors were used to separate connective tissue from the upper portion of the vertical ear canal. The diseased tissues were excised along with the upper third of the vertical ear canal by use of the No. 15 scalpel blade. Electrocautery was used for hemostasis. Following partial resection of the vertical ear canal, the incised margin of the remaining part of the canal was sutured to the pinna and surrounding skin margin with absorbable interrupted 3-0 poliglecaproneh sutures to complete the procedure (Figure 1). Sutures included the cartilage and overlying epithelium of the ear canal and pinna.
Intraoperative photographs depicting partial vertical ear canal resection in an 18-year-old domestic medium-hair cat that had multiple ulcerated ceruminous gland adenomas affecting the opening of the left external auditory canal with associated otitis externa (cat 1). A—The upper third of the affected vertical ear canal and associated diseased tissues are excised. B—The incised border of the retained vertical ear canal is grasped. Interrupted sutures to the apposing pinnal border were subsequently initiated at this central location. C—The left pinnal defect is closed. Notice the increased curvature of the pinna (cupping) associated with apposition to the smaller-diameter portion of the vertical ear canal.
Citation: Journal of the American Veterinary Medical Association 255, 12; 10.2460/javma.255.12.1365
Following closure, a separate 15-mm skin incision was created at the rostrolateral base of the pinna. A buried 3-0 nyloni mattress suture was secured to the rostral base of the pinna and the adjacent muscle fascia to tilt and rotate the pinna to match the position of the opposing ear. Interrupted 3-0 poliglecaprone sutures were used to close this small access incision (Figure 2). The resected tissue was submitted for histologic examination (Figure 3). Complete resection of the ceruminous gland adenomas was confirmed.
Photographs depicting completion of the surgery (A) and postoperative appearance of the affected ear (B and C) of cat 1. A—A buried mattress suture was used to pivot the affected left pinna rostrally by securing the rostral base of the pinnal cartilage to the adjacent muscle fascia. This improved symmetry with the right pinna. B—Craniodorsal view of the head immediately after surgery. C—Dorsolateral view showing the caudal aspect of the affected ear immediately after surgery.
Citation: Journal of the American Veterinary Medical Association 255, 12; 10.2460/javma.255.12.1365
Excised portion of the vertical ear canal and associated ceruminous gland adenomas from cat 1.
Citation: Journal of the American Veterinary Medical Association 255, 12; 10.2460/javma.255.12.1365
The patient recovered uneventfully after surgery and was discharged from the hospital the following day. Administration of buprenorphine hydrochloridej (0.02 mg/kg [0.009 mg/lb], PO, q 12 h) for 3 days and amoxicillin–clavulanic acidk (13.75 mg/kg [6.25 mg/lb], PO, q 12 h) for 5 days was prescribed. An Elizabethan collar was placed on the cat for one week, and reexaminations were performed periodically during the next year. The ear carriage was similar to that of the opposite ear, although the pinna was slightly shorter. One year after the partial ear canal resection, a 5 × 8-mm mass was observed on the rostrolateral margin of the vertical ear canal. The mass was resected with < 10 mm surgical margins around its base with the cat under general anesthesia. Histologic examination results identified a ceruminous gland adenocarcinoma. The geriatric cat was doing well with no evidence of recurrence at the last follow-up 4 months after the second surgery.
A 16-year-old 8.25-kg (18.2-lb) castrated male domestic shorthair cat (cat 2) was evaluated at the same surgery service because of multiple cystic nodules obstructing the opening and outer aspect of the left external auditory canal, making otoscopic examination problematic. Dermatitis and otitis externa were associated with these growths. The patient was deemed in reasonably good health on the basis of physical examination results. Hematologic and serum biochemical analyses were within the respective reference ranges. The patient was premedicated, anesthetized, and prepared for surgery of the affected ear in a manner similar to that described for cat 1.
A No. 15 scalpel blade was used to incise the medial base of the pinnal epithelial surface and underlying cartilage. Dissection and excision of the outer third of the vertical ear canal were similar to those for cat 1. The incision was deviated to include resection of the multiple ceruminous lesions and associated skin around the outer circumference of the opening to the ear canal. The incised border of the vertical ear canal was secured to the pinna and lateral facial skin with a series of absorbable interrupted 3-0 poliglecaprone sutures to complete the procedure (Figure 4). The cat recovered uneventfully from anesthesia and was discharged from the hospital on the following day with an Elizabethan collar to be kept in place for the following week. Buprenorphine and amoxicillin–clavulanic acid were prescribed at the same dosages as for cat 1. Histologic examination of the excised tissue confirmed ceruminous cystomatosis with surface colonization by yeast; ovoid to bilobed yeast organisms were present, which were compatible with Malassezia spp.
Intraoperative photographs depicting partial vertical ear canal resection in a 16-year-old domestic shorthair cat with ceruminous cystomatosis affecting the outer aspect of the left external auditory canal with otitis externa (cat 2). A—Resection of upper third of the vertical ear canal and associated affected tissues. B—Closure of the surgical defect by apposition of the incised margin of the pinna to the margin of the retained portion of the vertical ear canal.
Citation: Journal of the American Veterinary Medical Association 255, 12; 10.2460/javma.255.12.1365
Cat 2 was periodically reexamined over the next 10 months and was reportedly doing well at the last follow-up. Ear canal carriage and length were similar to those for the opposite ear, as noted for cat 1.
Discussion
There are 3 basic surgical procedures described for veterinary patients with ear canal disease, trauma, or congenital defects. These include lateral ear canal resection,1–5 vertical ear canal resection,1–5 and ear canal ablation.1–8 The technique to be used is selected on the basis of the location of the diseased tissue and extent of the ear canal involvement. Patients with lesions limited to the vertical ear canal are candidates for lateral ear canal resection or vertical ear canal resection, provided that the horizontal ear canal is intact and normal in diameter.1–5
Lateral ear canal resection provides exposure, drainage, and accessibility to the deeper aspect of the ear canal, but complete removal of diseased areas is limited to the lateral half of the vertical ear canal. With circumferential lesions or lesions confined to the medial wall of the vertical ear canal, complete vertical canal resection would be the preferred technique. During surgery, this procedure can be converted to a total ear canal ablation if the horizontal ear canal is involved in the disease process or is stenotic.
The veterinary literature describes vertical ear canal resection as complete or subtotal removal of the vertical ear canal: the outer edges of the smaller-diameter horizontal ear canal are then sutured to the skin below the pinna. There are various methods for securing the horizontal ear canal to the skin.1–5 Complete loss of the vertical ear canal results in partial loss of support to the erect pinna, and this can result in a downward tilt. Skin tension ventral to the closure can contribute to this cosmetic issue.8 Hair regrowth, especially in longhaired breeds of cats, will obscure the small, translocated horizontal ear canal ostium, necessitating clipping of fur around the area when medical management is required.
There are a variety of disease processes involving the external auditory canal that can encompass its circumference and the attached pinnal area.9 For the cats of the present report, the lesions involved the outer aspect of the external auditory canal, the lower pinna, and the upper third of the vertical ear canal, and the described technique was used by the author with consideration for obtaining surgical margins for possible neoplastic growths. In larger cats, it may be possible to excise an additional amount of the vertical ear canal. However, because the vertical canal tapers as it approaches the junction with the horizontal ear canal, closure as noted would be thwarted by the disparity between the smaller circumference of the remaining vertical ear canal and larger incised pinnal margin. If the obstructive disease process impedes otoscopic examination to determine the extent of the disease process, CT would be an option to assess the ear canal prior to surgery. Alternatively, partial ear canal resection could be performed (as in cat 2), allowing the surgeon to bypass the obstructed external acoustic meatus to determine whether additional resection is indicated.
Partial vertical canal resection as described in the present report was notably simpler to perform, in the author's experience, than complete vertical ear canal resection. This technique also resulted in less surgical trauma to the patient than would be expected with complete resection. Cosmetically and functionally, the ear canal and pinna on the affected side were largely preserved in both cats, despite the loss of the upper third of the vertical ear canal and associated tissues comprising the original external auditory canal. Direct suturing of the canal margin to the pinnal margin, in turn, helped to stabilize the vertical position of the external ear; slightly increased curvature (cupping) of the pinna also resulted from suturing to the smaller-diameter portion of the vertical ear canal. This cupping added to the stability of the pinna in its normal vertical position. Skin tension after closure was minimal and did not contribute to downward deviation of the pinna. In cat 1, a small access incision was used to place a mattress suture, securing the base of the pinna to the adjacent muscle fascia rostrally, to improve positioning of the ear in relation to the opposing ear. This was not required for cat 2.
The results for these 2 patients indicated that partial vertical ear canal resection largely leaves the involved ear in its normal anatomic configuration, with access to the remaining vertical and horizontal canals facilitated by the wider opening of the external auditory canal. The primary limitation of this technique would be that if a disease process extends into the deeper portion of the vertical ear canal or extends to the external acoustic meatus, this could necessitate conversion to a vertical ear canal resection or total ear canal ablation.
Footnotes
Opana ER, Endo Pharmaceuticals, Malvern, Pa.
Novaplus, Hospira Inc, Lake Forest, Ill.
Alfaxan, Jurox Inc, Kansas City, Mo.
Halocarbon Products Corp, River Edge, NJ.
Cefazolin, West-Ward Pharmaceutical Corp, Eatontown, NJ.
Baxter Healthcare Corp, Deerfield, Ill.
Dermachlor, Butler Schein Animal Health, Dublin, Ohio.
Monocryl, Ethicon, Guaynabo, Puerto Rico.
Monosof, Covidien, Mansfield, Mass.
Hospira, Lake Forest, Ill.
Clavamox, Pfizer Animal Health, New York, NY.
References
1. Mathews KG, Hardie EM, Murphy KM. Subtotal ear canal ablation in 18 dogs and one cat with minimal distal ear canal pathology. J Am Anim Hosp Assoc 2006;42:371–380.
2. Lanz OI, Wood BC. Surgery of the ear and pinna. Vet Clin North Am Small Anim Pract 2004;34:567–599.
3. Elkins AD. Surgery of the ear canal. Probl Vet Med 1991;3:239–253.
4. Bradley RL. Surgical management of otitis externa. Vet Clin North Am Small Anim Pract 1988;18:813–819.
5. Hobson HP. Surgical management of advanced ear disease. Vet Clin North Am Small Anim Pract 1988;18:821–844.
6. Hitt ME. Ablation of the ear canal for treatment of chronic suppurative otitis externa in a cat. Vet Med Small Anim Clin 1980;75:1007–1009.
7. Bacon NJ, Gilbert RL, Bostock DE, et al. Total ear canal ablation in the cat: indications, morbidity and long-term survival. J Small Anim Pract 2003;44:430–434.
8. McNabb AH, Flanders JA. Cosmetic results of a ventrally based advancement flap for closure of total ear canal ablations in 6 cats: 2002–2003. Vet Surg 2004;33:435–439.
9. Rogers KS. Tumors of the ear canal. Vet Clin North Am Small Anim Pract 1988;18:859–868.
