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Abnormal Passageway Between the Mouth and Nasal Cavity in Dogs


Oronasal Fistula in Dogs


A fistula is characterized as an abnormal passageway between two openings, hollow organs, or cavities. They occur as a result of injury, infection, or disease. A communicating, vertical passageway between the mouth and nasal cavity is called an oronasal fistula. Dolichocephalic dog breeds are more likely to be affected with this condition, especially the Dachshund.


These types of fistulas are caused by the diseased condition of any tooth in the upper jaw. The most common location for an oronasal fistula is where the root of the fourth premolar on the upper jaw enters the palate. This condition will need to be surgically corrected to prevent food and water from passing from the mouth into the nasal cavity. If this should occur, it will cause irritation of the nose, runny nose, inflammation of the sinuses, infection, and possibly pneumonia.


These fistulas can affect both dogs and cats. If you would like to learn more about how this condition affects cats, please visit this page in the PetMD health library.


Symptoms and Types


Symptoms of an oronasal fistula include a chronically runny nose, with or without bleeding, and persistent sneezing.




  • Trauma
  • Bite wounds
  • Oral cancer
  • Electrical shock
  • Periodontal disease
  • Traumatic tooth extraction
  • Mandibular canines (the fang-like teeth) positioned toward the tongue
  • Upper jaw overbites, which causes the canine teeth in the bottom jaw to pierce the hard palate (roof of the mouth)




You will need to give a thorough history of your dog's health, onset of symptoms, and possible incidents that might have precipitated/preceded this condition. Your veterinarian will perform a thorough physical and oral exam using a periodontal probe to investigate the suspected oronasal fistula.


A complete blood profile will be conducted, including a chemical blood profile, a complete blood count, a urinalysis, and an electrolyte panel. The blood-work should be performed before anesthetizing the dog for surgical correction of the fistula.




Surgical removal of the tooth, and closure of the passageway is the treatment of choice. A skin flap will be placed in both the mouth and in the nasal cavity during closure.


Living and Management


Since a flap to repair an oronasal fistula undergoes constant tension each time the dog breathes, oronasal fistulae tend to reopen. Additional surgeries with advanced tissue flaps can be performed if this occurs.


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