What is Bilateral Arytenoid Lateralization?
Bilateral arytenoid lateralization, also known as a 'laryngeal tie-back' operation, is a surgical procedure which repositions part of the larynx so the entrance to the trachea (windpipe) is widened. It is the treatment of choice for cats with laryngeal paralysis. This is a condition n which the paralyzed larynx stays in the 'closed' position, which narrows the airway and makes it difficult for the cat to breathe.
Laryngeal paralysis is less common in the cat than the dog, and in the majority of cases, the underlying cause is never found. Bilateral arytenoid lateralization is a delicate procedure and the outcome greatly depends on the skill of the surgeon. Some experienced vets in first opinion practice will attempt a laryngeal tie-back or referral to a specialist soft tissue surgeon may be appropriate.
Bilateral Arytenoid Lateralization Procedure in Cats
Under general anesthesia, a tube is passed into the trachea to provide a functional airway. The cat is placed on their side, with a shallow support under the throat so as to gently arch the neck upwards. The fur is clipped from the throat and neck area and the skin make surgically sterile.
Under aseptic conditions, the surgeon makes an incision just below the jugular vein. The muscles are carefully dissected aside until the structure of the larynx is exposed. Anatomical landmarks of the larynx are identified and the muscular attachments of the arytenoid cartilage are dissected away. Using a fine, non-absorbable suture material, the arytenoid is sutured to either the cricoid or the thyroid cartilage with the aim of making the entrance to the windpipe wider.
The clinician may then remove the tube from the windpipe and use a laryngoscope to check that the resting position of the larynx is wider. Once satisfied the positioning is correct, the tube is reinserted and the surgical site repaired and the skin sutured.
If both sides of the larynx are paralyzed then the cat is turned onto the opposite side, and the procedure repeated in its entirety.
Efficacy of Bilateral Arytenoid Lateralization in Cats
In the hands of a skilled surgeon this is an extremely effective way of improving the quality of life of a cat with laryngeal paralysis. A non-absorbable suture material is used so that the effects are permanent.
Without surgery, the impact of laryngeal paralysis depends on its severity. Those cats with full paralysis of both sides will struggle to breathe, even at rest, and have a poor quality of life. This could necessitate euthanasia as the most humane option.
Those cats with partial or unilateral (one-sided) paralysis may be able to cope by limiting exertion and therefore their oxygen requirements. They may however be left in a permanent state of oxygen starvation which leaves them reluctant to eat because it means taking time out from breathing to swallow.
Bilateral arytenoid lateralization is the surgical treatment of choice, but in an emergency situation a tracheotomy enables air to enter the windpipe directly and bypass the larynx. Cats can live with a permanent tracheotomy site, but are prone to complications such as aspirating material down into the lungs, which causes pneumonia.
Bilateral Arytenoid Lateralization Recovery in Cats
This surgery involves handling the laryngeal tissues which are particularly sensitive and prone to swelling or spasm. There is a risk in the immediate postoperative period of severe narrowing of the airway, making it difficult to breathe. Thus, the patient should be monitored all the time, and have an intravenous catheter in place. This allows immediate administration of intravenous drugs to reduce swelling, should the need arise. In addition, access to an oxygen tent is desirable, should breathing difficulties occur.
Other complications include hematoma formation at the operation site, which can sometimes require an emergency tracheotomy. These types of complications are usually evident within 24 hours, so most patients are able to go home at the 24 to 48-hour mark, once they are eating well and breathing normally.
The cat should rest in the postoperative period and the skin sutures are removed after 10 to 14 days.
Cost of Bilateral Arytenoid Lateralization in Cats
There are initial costs in reaching a diagnosis. This involves giving a general anesthetic ($99 plus), watching the movements of the vocal folds, and taking radiographs ($40 to $150 plus) to check for neoplasia.
If referral is necessary, the consultation with the specialist surgeon can be in the region of $200. The surgery itself and the aftercare is liable to be around $1,500 to $2,000.
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Cat Bilateral Arytenoid Lateralization Considerations
Bilateral arytenoid lateralization is a 'Goldilocks' procedure, since it needs to be done 'just right'. If the arytenoids aren't held back far enough, there is little point in the surgery; but if they are pulled too far apart then food may be inhaled into the lungs.
In the longer term, the sutures may tear through the laryngeal cartilage and the arytenoids return to their original position. This necessitates repeat surgery.
Bilateral arytenoid lateralization has a higher risk of complications than operating on one side alone. With this in mind, some experts suggest operating on one side, then leaving a gap of two to three weeks before operating on the second side. This not only checks that surgery to both sides is needed, but allows the clinician to manage complications arising from the first surgery in a more controlled manner.
Bilateral Arytenoid Lateralization Prevention in Cats
The laryngeal nerve is the longest in the body and pass along the neck and down into the chest cavity. Anything that puts pressure on the nerve or traumatizes it can potentially lead to laryngeal paralysis. Thus extreme care should be taken when restraining a cat with a collar around the neck. A harness is a much safer and more appropriate way of taking a cat for a leash walk.