spring & summer is peak time for…
Catherine Popovitch, VMD, DACVS, DECVS
Veterinary Specialty & Emergency Center
As the warmer weather approaches, we at VSEC start to see an increased number of patients that present with clinical signs of laryngeal paralysis.
The most common cause of laryngeal paralysis is idiopathic polyneuropathy, which results in the progressive loss of function of the arytenoids. (vocal folds)
The majority of dogs that present with laryngeal paralysis are older and larger in breed size. Labradors are quite commonly afflicted, and the average age at presentation is 10 years.
Clinical signs can develop over several months and even years in some cases, with a history of upper airway noise or stridor. This can initially take the form of harsh breathing that is often exacerbated by activity or warmer weather. There is also a reduction in exercise tolerance, and this decrease in activity level is often attributed to getting “old” when it is more related to compromised respiration. These dogs tend to be more prone to overheating . Owners often report coughing or gagging associated with eating and a change in the dog’s bark, having become horse or lost all together.
A complete work-up prior to surgery is important as these are older (sometimes very old) dogs that we want to make sure do not have any other major medical problems prior to proceeding with surgery. Full blood-work (CBC and Chemistry), chest and abdominal radiographs are routinely preformed. In some cases an abdominal ultrasound will be recommended, as would an evaluation for any co-existing neurologic disease.
Definitive diagnosis is via upper airway exam. Differentials include a mass or tumor obstructing the upper airway. This exam is done under light sedation, typically with titrate propofol. We often do this prior to intubation and will proceed with surgery if the diagnosis is confirmed, as this decreases the possibility of the patient having difficulty recovering from sedation. If you are just planning to evaluate the airway, it is important to be prepared to intubate the patient if they become compromised under sedation. On exam, movement of the arytenoids (vocal folds) is most often decreased bilaterally, although it can also be unilateral.
When we discuss elective surgery with pet owners, we talk mostly about improving the quality of life in these older patients. We will educate the owner that this paralysis has the potential to be life threatening if the dog over-heats, become distressed and then is unable to breathe in this distressed state.
The surgery we perform at the Veterinary Specialty & Emergency Center is a Unilateral Arytenoid Lateralization. (Tie-back) This places a suture through the arytenoid cartilage on one side (we routinely perform the surgery on the left side), opening up one side of the airway to allow for improved air flow. The downside of this procedure is that in permanently opening up one side of the airway, one removes the protective mechanism that prevents food from entering the trachea and lungs. The most common complication associate with this surgery is aspiration pneumonia, which can occur in up to 25 % of cases. The severity of the aspiration pneumonia range from mild and treatable with antibiotics, to severe and can result in death. A recent study determined co-existent megesophagus and treatment with opioid analgesics to be risks factors for aspiration. Having aspiration pneumonia prior to surgery did not correlate with development post-operatively; however, the risk of aspiration is long-term. Another potential complication is a breakdown of the suture placed to hold back the arytenoid cartilage. This failure can be a result of stress from excessive barking post-operative, or because of brittle cartilage in older dogs that cannot hold the suture securely.
Important Points of Emphasis for Pet-Owners
Over the years we at VSEC have made many changes in how we handle the peri-operative and post-operative care of these patients. These changes have deceased post-operative complications and greatly improved our success rate.
We prefer to perform surgery on patients that have not had a recent respiratory crisis. If possible we stabilize and treat these patients for any underlying pneumonia and schedule them for elective surgery.
Patients treated electively are admitted the morning of surgery and discharged shortly after the procedure. Managing cases this way has decreased post-operative complications such as; aspiration and breakdown of the sutures placed at surgery.
Patients kept hospitalized are often agitated and pant or bark incessantly. This places stress on the suture and necessitates sedation, which may increase the risk of aspiration. Usually, these older patients are happier going home to sleep quietly in their own environment.
As a result of Unilateral Arytenoid Lateralization (Tie-back), the majority of pet owners report a significant improvement in their dog’s quality of life.
Dr. Catherine Popovitch is a Board-Certified Surgeon at the Veterinary Specialty & Emergency Center. The Veterinary Specialty & Emergency Center operates state-of-the-art emergency and specialty veterinary hospitals that are open 24/7/365 in both Levittown PA and Philadelphia PA. For more information about our world-class emergency and specialty care, please visit VSEC on the web at www.VSECVET.com.