Surgery of the ear and pinna.

There are several disease processes of the ear and pinna that warrant surgical intervention. This article reviews surgical anatomy and common surgical procedures of the ear and pinna, including aural hematomas, lateral wall resection, vertical ear canal resection, total ear canal ablation and lateral bulla osteotomy, partial pinna resection, and feline inflammatory polyps. The clinical signs, diagnosis, and surgical treatment along with potential complications for each disease process are discussed.     

Potential factors affecting the outcome of dogs with a resection of the lateral wall of the vertical ear canal.

The records of 60 dogs that had a resection of the lateral wall of the vertical ear canal (Zepp) were examined. The surgical outcomes were evaluated in association with the following variables: breed, sex, age of onset of the otitis externa, duration of the disease before the surgery was performed, treatment received for the otitis externa, the status of the ear and tympanic membrane at the time of the surgery, the culture results, and concurrent medical problems. The outcome of surgery was acceptable in 45% and unacceptable in 55% of the cases. Breed was the only factor that could be correlated with the outcome. The procedure failed in 86.5% of the cocker spaniels. When surgical outcomes in breeds other than cocker spaniels were evaluated, 63% were acceptable and 37% were unacceptable. Sharpeis were found to have an ear canal of small diameter compared with that of other breeds and a tendency to have better outcomes.     

Surgical management of otitis externa

The surgical management of otitis externa is discussed in conjunction with failed medical management, primary causes, and proper case selection. The techniques of lateral ear canal resection and vertical ear canal ablation are described in detail.     

Surgical management of 43 cases of chronic otitis externa in the dog

: Over a seven-year period, chronic otitis externa was surgically managed in 43 dogs at the University Veterinary Hospital of University College Dublin. Lateral ear canal resection (LECR) was undertaken in nine of the 43 dogs: results were unsatisfactory, with a failure of the surgery in five of eight dogs and one dog lost to follow-up. Once end-stage otitis externa, with or without otitis media, is diagnosed, total ear canal ablation and lateral bulla osteotomy (TECA/LBO) is the best treatment option. In this series, 37 of 43 dogs underwent TECA/LBO and of the 29 dogs for which follow-up results were obtained 27 (93%) had an excellent or improved outcome to surgery. Complications following all procedures were most common in cases with a concurrent dermatopathy; therefore, definitive diagnosis and medical treatment for skin and ear disease is essential.     

Total Ear Canal Ablation Clinical Results in the Dog and Cat

The clinical results of 39 consecutive ear ablations (in 28 dogs and three cats) performed over a 15-year period were reviewed. Indications for ear canal ablation included hyperplastic tissue stenosis of the horizontal ear canal (23), failed lateral ear resections (13), and horizontal ear canal neoplasms (3). Ear ablation was successful in alleviating persistent signs of otitis in eight of 15 dogs with horizontal ear canal stenosis due to hyperplastic tissue, seven of 10 dogs with unsuccessful lateral ear resections, and two of five animals (three cats and two dogs) with horizontal ear canal neoplasms (follow-up time periods greater than 5 months). Surgical complications occurred following 82% of the ablations; wound infections (41%) and facial nerve damage (36%) were most common. Local wound and antibiotic therapy successfully treated prolonged drainage following ablation in five of nine dogs. Bulla osteotomy and drainage were successful in the treatment of three dogs (four ears) that were unresponsive to medical therapy with postoperative ear fistula following ablation, one of two dogs with prolonged ear drainage following ablation for failed lateral ear resection, and one dog with recurrence of signs of inner ear disease following ablation (follow-up period, 1 month to 4 years; mean, 3.4 years). Facial nerve damage caused by ablation was transient in nine of 14 ears, with most deficits returning to normal within 2 weeks.     

Surgical Management of Rabbit Ear Disease

Clinical signs associated with otic disease in rabbits (Oryctolagus cuniculus) are very similar to those demonstrated in dogs and cats. The surgical treatment options to resolve diseases involving the rabbit ear are also comparable with those used for canine and feline species. However, there are key anatomic and physiologic differences that must be accounted for to perform proper surgical treatment on a rabbit that has been diagnosed with ear disease. This article describes the diagnostic and treatment options for otitis externa, otitis media, and otitis interna, with an emphasis on surgical procedures and the important distinctive otic features of the rabbit patient. The ventral bulla osteotomy procedure is recommended for management of otitis media in rabbits without otitis externa. In rabbits with pathology in the external ear canal and the middle ear, total ear canal ablation and lateral bulla osteotomy should be performed. This combined procedure will allow the surgeon to address pathology in both sites, with the ultimate goal of resolution of the underlying disease etiology. Lateral ear canal resection is only appropriate in rabbits with otitis externa without otitis media; however, this surgical procedure may not resolve the otitis externa. If this is a concern, a total ear canal ablation should be done because it offers a greater chance of success.     

Surgical treatment of middle ear cholesteatoma using an oral approach in 2 dogs

Middle ear cholesteatoma is caused by the formation of epidermoid cysts that result in distention and enlargement of the tympanic bulla with subsequent destruction of surrounding tissues. We report treatment of middle ear cholesteatoma in 2 dogs, via an oral surgical approach. Abnormal tympanic bulla contents and the wall compressing the pharynx were successfully removed in both cases. Computed tomography imaging, surgical findings, and histopathology results were consistent with middle ear cholesteatoma in both cases. The outcomes in both cases suggest that an oral surgical approach may be an alternative treatment for middle ear cholesteatoma in dogs.Key clinical message:Despite the limited number of cases described herein, our report indicates that the direct oral approach for canine cholesteatoma may be and alternative approach.     

BAER testing in a dog with bilateral external ear canal atresia

A 3 yr old male castrated Labrador retriever presented for evaluation and treatment of bilateral atresia of the external ear canals. The owners reported that the dog could hear only loud and high-pitched noises. Computed tomography of the head revealed intact vertical and horizontal ear canals filled with debris and a debris-filled right tympanic bulla. Air- and bone-conducted brainstem auditory evoked response (BAER) testing revealed an elevated response threshold to air-conducted stimuli and greater amplitude waveforms evoked by bone-conducted stimuli. The ear canals were surgically corrected via lateral ear canal resection. BAER testing postoperatively revealed a decrease in the air-conducted BAER threshold. This case is an example of the use of bone-conducted BAER testing to aid in the diagnosis of conductive deafness, and in determining prognosis for normal hearing after surgical treatment of external ear canal atresia.     

Cholesterol granuloma as long-term complication of total ear canal ablation in a dog

A 13-year-old cocker spaniel presented with pain on opening the mouth. History of a previous left total ear canal ablation with lateral bulla osteotomy, left intermittent facial palsy and left intermittent head tilt suggested progression of a total ear canal ablation with lateral bulla osteotomy complication. Magnetic resonance imaging revealed a large mass arising from the tympanic bulla. Cytology of aspirates revealed a chronic suppurative inflammatory reaction and numerous cholesterol crystals. The mass was removed by surgical excision and an active drainage system was placed for a few days. The head tilt, facial palsy and apparent pain were resolved by the surgery. Physical examination was unremarkable nine months postoperatively. Bacterial cultures of the collected fluid were negative and histological examination confirmed the diagnosis of a cholesterol granuloma.     

Hilar Liver Resection in Dogs

Objective— To describe hepatic vasculobiliary anatomy important to hilar liver lobe resection in the dog.
Study Design— Experimental study.
Animals— Canine cadavers (n=7).
Methods— The vasculobiliary system of 7 fresh canine livers was injected with a polymer. The parenchyma was dissected at the level of the hilus to determine the vascular and biliary supply to each liver lobe, and then macerated with a corrosion preparation. The information gathered was used to describe a surgical approach for hilar liver lobe resection.
Results— Each liver lobe had a single hepatic artery and biliary duct. The location of these structures was consistent, although minor variations existed (dorsal versus ventral to the lobar portal vein) in the left lateral lobe and papillary process in 2 specimens. Most liver lobes (34/49) were supplied by 1 lobar portal vein and drained by 1 lobar hepatic vein (39/49). The location of the portal and hepatic veins was consistent among specimens.
Conclusions— The left division is the most mobile of the liver lobes and each lobe can be removed separately or en bloc. Because of the location of the hepatic veins, the central division is best removed as a single unit. The right lateral lobe can be removed individually or together with the caudate process. The papillary process is removed by itself.
Clinical Relevance— A hilar liver lobectomy technique can provide an alternative approach to conventional procedures for tumors that encroach upon the hilus of the liver.     

Bulla curettage for chronic otitis media and interna in dogs.

In a series of 10 clinically affected and 6 clinically normal dogs, the technique of bulla curettage via the external ear canal, after lateral ear resection, was evaluated. In 5 of the 10 dogs with chronic otitis media and interna, the head carriage became normal 2 to 8 weeks after surgery and remained so for at least 18 months; 4 other dogs improved, but the improvement was either temporary or incomplete. In the clinically normal dogs, postsurgical complications were minimal; the tympanic membrane healed completely in 4 of the 6 dogs.     

Otitis media in a llama

A 7-month-old female llama was examined because of chronic otitis media and externa of 7 months' duration. Radiographically, the tympanic bullae appeared thicker than normal, and the ventral borders were poorly defined; the left external acoustic meatus (ear canal) appeared to be narrower than the right. The llama was treated with penicillin, and the ear canals were lavaged daily. Contrast radiography was performed on day 15 to determine the shape and size of the ear canals and evaluate the integrity of the tympanic membranes. Contrast medium was visible radiographically in the left tympanic bulla, indicating that the left tympanic membrane was ruptured, but the right tympanic membrane appeared to be intact. The left ear canal was narrower than the right, and the bony ear canals had a well-defined sigmoid shape. The right ear improved with medial treatment alone, but the left ear did not. Therefore, lateral ear canal resection was performed. After surgery, however, exudate was still evident in the left ear canal, and the llama became more lethargic and more reluctant to eat. Lateral bulla osteotomy was attempted, but no purulent material was obtained, and curettage of the bulla resulted in hemorrhage. Because of this and because of the llama's poor physical condition, a decision was made to euthanatize the llama. The sigmoid shape of the bony ear canal and the multicompartmental nature of the tympanic bulla make surgical treatment of otitis media and externa in llamas difficult. Further study of surgical treatments for otitis media in llamas is needed.     

Right Dorsal Colon Resection and Bypass for Treatment of Right Dorsal Colitis in a Horse

Objective: To describe a novel surgical technique for management of right dorsal colitis in the horse. Study Design: Clinical report. Animals: 14‐year‐old Warmblood gelding. Methods: The horse was referred for treatment of a stromal abscess and signs of right dorsal colitis. Plasma chemistry revealed marked hypoproteinemia. Abdominal ultrasonographic examination showed a thickened right dorsal colon (RDC). Medical treatment was unsuccessful. With the horse in left lateral recumbency under general anesthesia, an approach to the right side of the abdomen through a 16th rib resection was made. The thoracic cavity was entered during the approach. Surgical resection of the RDC and side‐to‐side anastomosis of the diaphragmatic flexure to the small colon (bypass) was performed. The thoracic cavity was closed by attaching the diaphragm to the body wall and air was removed at the completion of surgery. Results: Resection of the RDC and bypass of the resected area was successfully performed. The colic signs and hypoproteinemia resolved. Complications of surgery included a deep surgical site infection with development of a large intrathoracic abscess. The abscess was managed with drainage and long‐term antimicrobial treatment. Conclusion: Right dorsal colitis can be treated successfully with resection and bypass of the RDC. In cases where the thoracic cavity is penetrated during the abdominal approach, the diaphragm should be sutured to the body wall at the beginning of surgery to avoid development of an infection within the thoracic cavity. Clinical Relevance: RDC resection and bypass may be an alternative approach for management of horses with right dorsal colitis.     

Total ear canal ablation and lateral bulla osteotomy in the dog

One hundred total ear canal ablation/lateral bulla osteotomy procedures were performed in 71 dogs over a four year period. The main indication for surgery was advanced disease of the aural canal or middle ear resulting from prolonged inflammatory disease of the outer ear. Complications of surgery included facial nerve injury, inner ear injury, retroglenoid vein haemorrhage and wound dehiscion. The incidence of complications (29 per cent) was, however, substantially lower than has previously been recorded following this procedure. Meticulous dissection technique and increasing familiarity with the procedure were thought to be responsible for lower complication rates than have previously been recorded. Surgery was considered to have resolved the original aural condition in 92 per cent of cases and only infrequently resulted in complete loss of hearing function.     

Multiple keratomas in an equine foot

A 19-year-old, Arabian gelding was presented for left hindlimb lameness and deviation of the hoof wall. Radiographs revealed a semicircular, radiolucent area in the lateral edge of the distal phalanx. Three distinct keratomas were successfully removed following hoof wall resection.     

Para-aural abscessation following traumatic ear canal separation in a dog

Traumatic ear canal separation is rare in animals, with only eight dogs and one cat reported with the condition in the English language literature. Para-aural abscessation occurred in six of these nine animals. Diagnosis was made on otoscopic observation of a shortened, abruptly ending external ear canal that was free from advanced disease. Radiographs in those cases which have been described showed a disruption of the normal air opacity of the affected ear canal. Drainage, by creating a separate opening for the horizontal ear canal, or total ear canal ablation and lateral bulla osteotomy (TECA/LBO), have led to resolution of the clinical signs. This report adds a further case to the literature in which TECA/LBO was employed successfully.     

Reconstruction of the lower eyelid by third eyelid lateral advancement and local transposition cutaneous flap after "en bloc" resection of squamous cell carcinoma in 5 cats

OBJECTIVE: To describe a novel technique for blepharoplasty to cover a tissue defect involving >/=50% of the lower eyelid. STUDY DESIGN: Prospective clinical study. ANIMALS: Five cats with lower eyelid squamous cell carcinoma (SCC). METHODS: En bloc resection of SCC by removing >/=50% of the lower lid with either the medial or lateral canthus was performed without other adjunctive treatment for SCC. The lid defect was reconstructed with a transposition skin flap derived from the frontal (medial defect) or temporal (lateral defect) region. The third eyelid was advanced laterally without dissection from its insertion; its outer conjunctival layer was removed, and the skin flap was sutured with single interrupted sutures dorsally over the nictitating membrane, ventrally to the cutaneous edge of the surgical wound and medially or laterally (depending on the canthus removed) to the skin of the remaining lower lid. RESULTS: Satisfactory cosmetic and functional results were achieved and the Schirmer tear tests were normal. In 2 cats, the skin flap needed monthly hair trimming to avoid corneal lesions. CONCLUSIONS: After en bloc resection of SCC involving >/=50% of the lower eyelid, reconstruction can be achieved by relocation of the third eyelid and use of a cutaneous transposition flap sutured to the scarified external surface of the third eyelid. Eyelid apposition and lacrimal function were preserved. CLINICAL RELEVANCE: Blepharoplasty using a cutaneous transposition flap sutured to the scarified surface of a relocated third eyelid should be considered for reconstruction of lower eyelid defects with >/=50% tissue loss of the lid margin.     

Aural cholesterol granuloma in a dog

A five-year-old female Irish setter was referred for surgery for a left-sided aural mass. The dog was generally well, but had signs of left-sided otalgia for one week. Biopsy identified the lesion as a cholesterol granuloma. The mass was removed three weeks later by a total canal ablation/lateral bulla osteotomy. The dog recovered from surgery without any complications. Ten months later, there was no evidence of recurrence. The purpose of this paper is to report the clinical and histopathological findings of this unusual form of granuloma which has not previously been reported in the canine ear.     

Total ear canal ablation combined with lateral bulla osteotorny in J the cat

Eighteen total ear canal ablations combined with lateral bulla osteotomy (TECA/LBO) procedures were performed in 15 cats over a period of 30 months. The indications for surgery included neoplastic disease, ceruminous gland adenocarcinoma of the horizontal canal or middle ear (10 ears), squamous cell carcinoma extending from the pinna (four), polyps emanating from the middle ear (three), and chronic unremitting middle ear disease (one). Complications associated with surgery included facial paralysis (seven cases), facial neuropraxia (four), Horner's syndrome (three), and wound dehiscion (one). Eleven cats were alive and disease-free six months after the surgery. The results indicate that the major indication for TECA/LBO in the cat is neoplastic disease involving the ear. Unlike the procedure in the dog, for which the usual indication is benign end-stage ear disease, neurological complications are common despite meticulous surgical dissections. In addition, the postoperative prognosis is guarded because of malignant disease in many cases.     

Clinical results of lateral ear resection in dogs

Twenty-six dogs had lateral ear resection performed for the treatment of chronic otitis externa. After a mean follow-up period of 4.5 years, 17 of the 26 dogs were available for physical examination. The remaining 9 dogs died prior to this review; their owners were surveyed by questionnaire. In the examined group, the resolution of clinical signs was good in 41% of the dogs, improved in 12%, and poor in 47%. A good result was defined as the elimination of clinical signs, with minimal or no care required from the owner. An improved status was assigned to dogs that experienced occasional recurrence of signs requiring professional attention. A poor result was defined as no improvement.