Zepp and Lacroix Procedures

The occasional ear infection is a nuisance but at least it can be expected to resolve in two to four weeks, leaving the patient to resume a normal life. Chronic ear infection can be recurring or on-going. It can lead to dizzying middle ear infections, unending headaches and pain, as well as permeating foul odor. There comes a point when simply managing the infection with cleaning solutions and oral medications is not enough and surgery must be considered.

There are two techniques commonly used to benefit the patient with chronic otitis: the lateral ear resection and the total ear canal ablation. The lateral ear resection is the more conservative approach meant for ears not yet at their end-stage where it is thought that more efficient cleaning and better canal ventilation will help.

How the Surgery Works

The ear canal of dogs and cats consists of both a vertical portion and a horizontal portion, making a J-shaped ear canal (darker line in above diagram). This configuration is different from the human horizontal-only canal, which goes straight into the head. Because of the vertical portion that dogs and cats have, it is thought that infectious debris and wax has a harder time draining and that this is an important factor in why dogs and cats have so many ear infections relative to humans.

Wouldn’t it be nice if we could get rid of the vertical ear canal and only contend with a horizontal ear canal? Well, it turns out that we can.

In a normal dog, the ear flap and vertical ear canal form a funnel-shape with the vertical canal being the neck of the funnel. In other words, looking down a dog or cat's ear is like looking down a funnel or cone. Photo by MarVistaVet

In the LaCroix procedure, the outer (lateral) part of the vertical canal is simply removed and the new ear opening is formed from the tissue in the area. Either way, the result creates an ear opening that is more like the human ear opening: straight in. The ear can be more easily cleaned, and since ventilation is now better the canal is less suited to incubate bacteria. Photo by MarVistaVet

Normal ear. Illustrations by Dr. Wendy Brooks

The lateral ear resection cuts the vertical canal in half lengthwise down to where the canal turns horizontal. In the Zepp procedure, one version of the lateral ear resection, skin is removed from the area on the outside of (or lateral to) the ear so that the dissected half of the ear canal can be folded down to form a drain board. In the LaCroix procedure, the outer (lateral) part of the vertical canal is simply removed and the new ear opening is formed from the tissue in the area. The result either way creates an ear opening that is more like the human ear opening: straight in. The ear can be more easily cleaned and since ventilation is now better, the canal is less suited to incubate bacteria. This procedure is relatively simple.

The dotted line indicates first set of incisions, through the skin and cutting the round ear canal in half lengthwise. Illustrations by Dr. Wendy Brooks

Post-operative care after lateral ear resection includes the use of an Elizabethan collar to protect the delicate incisions from scratching. This is worn for 10 to 14 days at which time any external sutures can be removed.

Aftercare

The ear will still require treatment of its infection so topical and oral medication will continue to be used.

The Caveats

Before calling up your veterinarian’s office to schedule this procedure, there are a few facts to be aware of.

• The underlying cause of the ear infection is not addressed by this procedure. If the pet has allergies, hormonal issues, or problems beyond ear conformation as the predisposing factors to chronic ear infections, this surgery addresses none of them and infections are still likely to recur. This surgery simply makes cleaning the ear easier.

The dissected ear canal is pulled down and the flap is sewn to the skin. The circle indicates the new opening of the ear canal. Illustration by Dr. Wendy Brooks

• If the patient has developed proliferative ear growths down the canal (a common occurrence that makes ear cleaning particularly difficult) and these growths are in the horizontal canal as well as the vertical one, then this surgery will not be successful. To check for narrowing all the way down the canal, a radiograph taken under sedation should indicate how narrow the horizontal canal is. Ideally, more advanced imaging of the ears should be performed, such as MRI or CT, to rule out a middle ear infection or inner ear tumors. Either of these situations would indicate need for a more aggressive surgery; however, this kind of imaging is not available to pets in many communities while most veterinary hospitals have capability to perform radiographs.
  
  
• One well-known study reviewed 60 dogs receiving lateral ear resections. The procedure was considered a failure in 86.5 percent of Cocker spaniels in which it was used. In other breeds, 63 percent were found to have acceptable results. If your dog is a Cocker Spaniel with long-standing ear canal disease, then the total ear canal ablation is likely more appropriate.
  
  
• If there is any reason to think a dog has a middle ear infection (see vestibular disease) a lateral ear resection will not provide adequate control of the situation.
  
  
• Some surgeons strongly prefer that the lateral ear resection be performed before a total ear canal ablation (TECA) in case the more conservative procedure is successful. If you are leaning towards the TECA surgery, check with the surgeon to be sure they are willing to do it in your pet’s situation without a prior lateral ear resection.
  
  
• One of the chief complications of the lateral ear resection is stricture at the entrance of the re-shaped ear canal. In other words, the new ear canal entrance may scar into a hole too narrow for proper ear treatment. This complication requires a revision of the ear canal entrance and is generally simple.
  
  
• The other classical complication of lateral ear resection is called dehiscence, which means that the stitches do not hold. This happens when there is too much tension on the tissue or too much infection. If this occurs, the tissue is left to heal in naturally, which takes longer than healing with stitches. The Elizabethan collar will be needed in this event until healing is complete.

The last thing you want to do is put your pet through an ear surgery only to find you should have done a different surgery. The Lateral Ear Resection is right for selected cases as described and would be totally useless for other patients. Be sure to discuss all the ear surgery options with your veterinarian and what diagnostics would be useful in helping with this selection. The goal is for your pet to finally gain relief from long-standing ear discomfort.