Canine Oronasal Fistula

Mona Lisa has a common problem. Dental calculus and resulting gingivitis have caused tooth loss, including her upper canine teeth.

Some pets are more likely to have dental disease than others. Contributing factors include:

  • pH of the mouth/saliva
  • resident bacteria
  • eating soft food
  • inability to brush teeth frequently
  • poor nutrition

Mona Lisa is not cooperative for tooth brushing, plus she has inherent factors that predispose her to rapid tartar collection and resulting recession of the gums. Once a tooth loses gum support, and bone around the roots begins to deteriorate, a tooth will not be anchored in place much longer.

Here, the flap from the palate has closed the opening (fistula) and the buccal (cheek) flap is about to be closed.

A dog’s upper canine teeth have extremely long roots, almost as long as the crown of the tooth. With that much support, they will remain in place despite substantial undermining by root disease. Often they are among the last teeth a dog loses.

Their extraction causes a problem because the tip of a healthy canine tooth root is separated from the nasal passages only by a thin layer of bone. Early in the process of root disease that bone is lost, and the tooth acting as a “plug” is the only barrier to food entering the nasal cavities during meals. The resulting passageway is called an oronasal fistula.

Potential sequelae  include impaction of the nasal passages with food, infection, sinusitis, even aspiration pneumonia if inhaled food enters the lower airway.

Most practitioners prefer to allow a time period between extraction and surgical repair of the fistula. Doing so allows the area to “quiet down,” become less inflamed, and even reduce the diameter of the opening.

Surgical repair is sometimes referred to a veterinary dental expert and we chose to have Dr. Andy Duke of Mobile, AL, perform Mona Lisa’s procedure. I have done this repair before and many general practitioners do.  Dr. Duke is a Fellow in the Academy of Veterinary Dentistry.

The process begins with creating two flaps, one that comes from the hard palate, one from the adjacent cheek. The two flaps are “married” to join over the opening, thus ending communication between the oral and nasal spaces.

The accompanying photos show her left fistula prior to surgery, the first flap sutured closed and the final view with the surgery finished.

Most veterinary dentists administer broad-spectrum antibiotics and pain-relieving medications after surgery. Mona Lisa’s sutures are absorbable, negating the need for postoperative suture removal.

See you next week, Dr. Randolph.


  1. Do orno nasal fistulas always have to be closed? My dachshund has periodontal disease and one of her upper teeth by the canine fell out and left the hole exposed, my vet said it likely will never close. I asked if she needed surgery and was told no, to just flush it after meals. I’m afraid to do that incase I make her aspirate. She’s been snoring alot more lately. She’s 10. Should I get a second opinion? Do they always have to be closed up with surgery? If you could help me I would appreciate it greatly thank you

    • I always recommend having them surgically closed. It’s a trick surgery, and not everyone wants to try it. If your primary veterinarian doesn’t want to, he can refer you to a board-certified veterinary dentist. Having said that, in my experience, many of them close on their own, given enough time. The “trick” is to prevent aspiration in the meantime, which has not been a problem in our practice. Thanks for reading, Dr. Randolph.

      • We took in a 7 yr old beagle after her owner had to go into nursing facility due to Alzheimers. She had many issues but the one that bothered her the most were Canine Oronasal Fistula. After doing research on her with the rescue she had come from I found out she had severe dental disease when she came into the rescue and they had most of her teeth pulled and was then adopted by this 92 yr old woman who did no follow up after the adoption and 3 Oronasal Fistula developed which she lived with for over 2 years. After we got her we had them surgically fixed but only one took. The vet went back in and closed the other two but only one of them took and she still has one Oronasal Fistula. We will need to wait at least another year before they can try again. Other than runny eyes she doesn’t seem to bothered by it right now., I have been trying to find something holistic or natural I can give her orally hoping that it may help in closing the final fistula but cannot seem to locate anything. Any suggestions would be appreciated.

        Thank you

        • In my experience, there are two things that can heal oronasal fistula in dogs: oral surgery and time. I’ve been amazed at how many dogs close their fistulae on their own. That said, I’ve had the best outcomes by sending my patients to a board-certified veterinary dentist who practices about an hour from us for surgery. I don’t imagine anything dietary is going to make a difference. God bless you for taking in your friend’s dog.

          • THANK YOU! My dog’s dentist said she had an oral fistula but she is healthy and fine. She has a little periodontal disease but I am now proactively thoroughly brushing her teeth and using bee proplis and a few other herbal antibacterials and aloe to treat her gums. I am also giving her a calcium algae, stem cell and lcarnitine supplements to help generate tissue and bone. Thank you for saying it could heal on its own.

          • Thank you, Shana. I want to emphasize that fistulae can SOMETIMES heal on their own, but SOMETIMES they need surgical repair. Your veterinary dentist can continue to advise you. Thank you for reading, Shana, Dr. Randolph.

  2. Tis odd, as we have fostered many a dachsie for a well-known dachsie rescue, we up till last August, 2013, we owned 5 dachsies including one who had not walked in 11 years, not one of them ever had fistulas, they had their teeth done perhaps in two cases twice a year and never had the fistula problem.

    • Thank you for the compliment, Sandi. Actually, there isn’t exactly a genetic component, except from the standpoint that smaller breeds of dogs are prone to calculus buildup and gum disease than larger breeds, and, of course, body size is genetic! Click here to read about beginning the toothbrushing process in a way that encourages pets to accept it and stay on a good preventive program.

    • Thank you for the information and reply. We have begun with gentle brushing the remaining teeth. I
      am considering a anti plaque to put in their water. Even when the fistulas are repaired she has a bad case of reverse sneezing, regular sneezing, mucuous coming out of her nose most most of the time.

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