Aspiration pneumonia after a dog's tie-back surgery is a dog owner's worst nightmare. Among the possible types of complications associated with this surgery, pneumonia is the most feared and the one dog owners mostly hope to avoid. And who can blame such concerned dog owners? Pneumonia is a potentially life threatening condition. A dog's lungs are meant to deal with air and are therefore poorly equipped to handle any food material, water or other matter that happens to reach them. Aspiration pneumonia after a dog's tie-back surgery can be overwhelming for the immune system, but fortunately when caught earlier, the prognosis is brighter.
Aspiration Pneumonia After a Dog's Tie-Back Surgery
Tie back surgery, also known as arytenoid lateralization laryngoplasty remains the most widely used surgical technique to correct laryngeal paralysis in dogs.
The goal of this surgery is to widen the glottis, the part of the larynx with a slit-like opening between the vocal cords, so that the dog can breath better.
While this surgery helps dogs breathe better immediately, it's import to point out that it doesn't restore the larynx to a normal function, explains veterinary surgeon Dr. James Fingeroth.
The main disadvantage of this surgery is that, the widening of the glottis increases the chances for aspiration pneumonia. With the cartilage "tied back" there is more room for food/liquids to go down the "wrong pipe."
For this very reason, surgeons opt for unilateral procedures, where only one side is abducted (tied back), as bilateral procedures would greatly increase the chances for aspiration pneumonia after surgery. Years ago, when both arytenoids were tied back (bilateral), this resulted into a 67 percent mortality rate, hence why it's no longer done.
Aspiration pneumonia is a condition that occurs when foreign matter (crumbs, food particles, water, vomit) is aspirated into the lungs. This condition usually develops fairly quickly after these substances have been inhaled, possibly as early as within 24 hours. Aspiration pneumonia initially leads to an airway response, then an inflammatory response, and then follows the onset of a secondary bacterial infection.
What Statistics Says
First the good news: reports from dog owners having their dog undergo tieback surgery revealed 80 to 100 percent success. Dogs show immediate improvement in breathing after this surgery. These encouraging numbers can make the decision-making process of performing the surgery appear like a no-brainer but the scary aspiration pneumonia complication can frighten even the most assured dog owner.
Another good news is the fact that among several other types of surgeries performed to fix the impaired larynx, (ventriculocordectomy, partial arytenoidectomy, modified castellated laryngofissure, unilateral arytenoid lateralization (tieback surgery) has been associated with the lowest complication rates.
But what do statistics say? How common is aspiration pneumonia after a dog's tieback surgery? According to a study, it was found that out of several tieback surgeries, about 25 percent of dogs developed aspiration pneumonia.
In another study, it was found that out of 232 dogs who underwent left-sided unilateral arytenoid lateralization, at the 1,2, 3, and 4-year follow-up periods, aspiration pneumonia occurred in 18.6 percent of dogs at one year, 27. 2 percent at two, 31.8 percent at three and 31.8 percent at four.
Aspiration pneumonia following surgery may occur anywhere along the postsurgical period or even a year later, explains veterinary surgeon Dr. Don R. Waldron. However, the risk of aspiration pneumonia seems to be present life-long when dealing with this disease, even years after surgery. Dogs may get it as early as the night of surgery, but also months or even years later. This because dogs after surgery still continue to have a compromised airway. Dogs with esophageal dysfunction (megaesophagus) are at a significantly higher risk for developing aspiration pneumonia after surgery.
Even in dogs not undergoing tieback surgery, the risks for aspiration pneumonia are there. While the larynx is meant to open during inhalation, it’s also supposed to close completely during swallowing (or vomiting which is swallowing in reverse) to prevent food from entering the windpipe, but in dogs with laryngeal paralysis, complete closure won’t occur, predisposing them to this serious complication since the airway is not protected.
What Can be Done to Prevent It?
Following the surgery, most dogs go home the same day. It's important to discourage barking and excess activity. To prevent aspiration pneumonia, post-surgical instructions often suggest feeding the dog small, moist meals (like meatballs) several times a day for 3 to 5 days.
While aspiration pneumonia is seen at times following tieback surgery, dog owners shouldn't go into panic mode or endure sleepless nights in fear of this complication. However, they should keep an eye on their dog for signs of this complication.
On a positive note, after the surgery, dogs are still equipped with their epiglottis, that flap of cartilage located at the root of the tongue that depresses during swallowing to cover the windpipe opening. Fortunately, this failsafe mechanism is still there to help, explains veterinarian Dr. Loretta.
Long term, dog owners may be instructed to feed soft, moistened foods. Overly dry food (kibble), dusty foods, or liquid diets are not recommended due to the risk of aspirating them. If kibble is fed, veterinarians are likely to suggest to feed it soaked. Follow your vet's post-surgical instructions carefully.
Collars should be avoided and dogs should wear harnesses for the rest of their lives. Swimming should also be out of question since this activity puts dogs at risk for aspiration pneumonia. Vigorous exercises and overly stressful situations especially in hot weather should be avoided. Anxious dogs should be prevented from scarfing down their meals.
The objective of this procedure (cricoarytenoid cartilage lateralisation) is to prevent passive adduction of the arytenoid cartilage during inspiration by fixing it to a neutral to slightly lateralized position. This modification still allows adequate epiglottic coverage of the rima glottidis during swallowing and is believed to reduce aspiration-related complications. ~ Journal of the South African Veterinary Association
At the Vet's Office
After tieback surgery it's paramount that dog owners learn how to recognize early signs of aspiration pneumonia.
Early signs of aspiration pneumonia after a dog's tieback surgery include faster breathing, along with breathing difficulty, lethargy, depression, lack of appetite and fever. Some dogs may also develop a moist-sounding cough which sounds different from the coughing following drinking and eating that's somewhat expected after surgery and that should diminish overtime.
If you suspect your dog has aspiration pneumonia, see your vet immediately. Do not wait for your dog to improve on his own or the next day. The earlier it is treated, the better.
Once at the vet, your vet will examine your dog and take his temperature. Dogs with aspiration pneumonia tend to have a fever. Chest x-rays can confirm the presence of aspiration pneumonia in dogs. Dogs with aspiration pneumonia are placed on broad-spectrum antibiotics.
After 3 to 4 days on broad-spectrum antibiotics, the dog should be expected to be breathing a little easier and the gums should be pink, explains veterinarian Dr. Gabby. Many cases are treated on an outpatient basis, but severe cases may require hospitalization for fluid therapy and intravenous antibiotics.
The prognosis of aspiration pneumonia in dogs varies based on several factors. As mentioned, one important factor is seeking treatment as soon as possible, hence the importance for dog owners to recognize early signs. The survival rate for dogs with post- surgical aspiration pneumonia in a study was 83.1 percent at one year, 51.5 percent at 3 years and 25.8 percent at 4 years.
- Brooks WC. Laryngeal Paralysis. Veterinary Information Network, Published 19 June 2006.
- Twin Cities Veterinary Surgery, Post-operative Information: Laryngeal Tieback
- Katherine L. Bahr, Lisa Howe, Carl Jessen, and Zachary Goodrich (2014) Outcome of 45 Dogs With Laryngeal Paralysis Treated by Unilateral Arytenoid Lateralization or Bilateral Ventriculocordectomy. Journal of the American Animal Hospital Association: July/August 2014, Vol. 50, No. 4, pp. 264-272