Ron Hines DVM PhD 4/24/06

This article does not deal with cosmetic ear surgery. Cosmetic surgery or ear cropping is performed for the vanity of pet owners. I try to talk owners out of it whenever I can. Instead, this article discusses a surgery that often cures stubborn ear infections that no longer respond to medications.

Another article in this series discusses the various causes of ear infection. Infections that reoccur over and over again all result in a similar situation – a disease that no longer respond to antibiotics with permanent changes in the ear canal. Most veterinarians postpone this operation – possibly longer than we should. The usual sequence of events is that we try every form of ear mediations sold and concoct a few of our own before we inform the owners that surgery may be the best answer. The ear is an ideal place for recurrent infection. Floppy-eared dogs have poor air circulation within the canal to begin with. The ear canal slopes upward so that it does not drain readily. It is lined with a membrane which, when inflamed for any reason, secretes a moist exudates ideal for bacterial and mold growth. In normal ears, sebaceous glands secret a translucent ear wax. In ears that have long been infected, apocrine tubular glands become more numerous and secrete a sticky brown material, rich in nutrients that support bacterial and mold growth. Infections also cause scaring which narrows the canal and obstructs drainage and air circulation.

It is unclear why relatively few dogs undergo total canal ablation since the results are usually excellent. There are a number of surgical operations for external ear infections that spare varying amounts of diseased ear canal tissue. These include lateral or vertical ear canal resection, Zepp Otoplasty and some forms of ventral bullar osteotomy. In my experience, these other procedures are ineffective in more than fifty percent of the cases. Total ear canal ablation is almost always successful. The secret of this success is in choosing surgical candidates wisely. Canal ablation must be combined with middle ear drainage and curettage (scraping) if it is to succeed in deep infections. In deep ear canal disease, infections have passed beyond the eardrum and affected the middle and inner ear. These dogs have specific signs related to the deeper infection. They often hold their heads cocked with the affected ear down. They may circle toward the affected ear and the eyelids and lip on that side may be droopy. They often walk cautiously and have problems keeping their balance. X-rays of the head sometimes show the extent of damage.

Once I have decided which procedure I will use, I begin the dog or cat on 10-14 days of presurgical antibiotics. It is helpful to have a bacterial culture taken from the ear to help chose the best antibiotic possible. With the pet asleep, the ear area is shaven and the ear canal flushed with detergents and antibiotics. A blue surgical marker is used to delineate the area that is to be removed. Because the ear canal is very vascular (bloody) I like to perform this surgery with an electric knife (electro surgical apparatus). A T-shaped incision is made over the ear canal and all diseased tissue and ear canal cartilage is removed (see diagram). I take special care to locate and avoid the facial nerve, which runs just below the ear canal. This nerve is responsible for tear secretions in the eye as well as eyelid and lip function on that side of the face. Stretching or cutting this nerve will lead to complications. I also isolate and avoid nicking the parotid salivary gland that surrounds the base of the ear. I do not worry that much about hearing loss. Most of the dog and cats that have ear disease extensive enough to warrant surgery already have some degree of hearing loss.

After the surgery I put dogs on meperidine, a narcotic pain reliever, for several days. Cats do not tolerate pain medications nearly as well as dogs. I limit cats to warm solutions containing topical anesthetics and DMSO for use on the surgical site. I keep these patients at the hospital until they are eating well and up and around. During this period they receive injectable broad-spectrum antibiotics. I send them home on oral antibiotics for an additional two to three weeks. Occasional complications are to be expected in any surgery. The older the dog is when this surgery is performed, the slower healing occurs and the greater the risk of complications Salivary gland leakage into the surgical field occurs occasionally. These generally resolve by themselves with time. Damage to the facial nerve, either due to the ear infection or stretching of the nerve during surgery usually resolves during the next few weeks. If it should remain, it may be necessary to apply eye drops to the affected eye on a routine basis to prevent dry eye.

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