Oronasal Fistula Closure in Dogs

An oronasal fistula occurs when a gap exists between the nasal passage and the incisive, maxilla, or palatine bones of the oral cavity. This opening allows water, food, and other substances to pass from the oral cavity into the nasal passages, which results in inflammation of the respiratory tract, sneezing and nasal discharge, and infection of the nasal passages (chronic rhinitis). The main reasons oronasal fistulas occur are from trauma caused during tooth extractions, by penetration of foreign bodies, by periodontal disease, or from cancer. Surgical repair of these openings is important to prevent foreign objects from entering the nasal passages and respiratory system. Closure of oronasal fistulas is performed by a veterinarian under anesthetic.

Your veterinarian will do an examination of your dog to ensure they are fit to undergo anesthesia and surgical closure of an oronasal fistula. As chronic respiratory problems are associated with this condition,your veterinarian will be particularly attentive to your dog's respiratory condition and may require tests or medication prior to surgery to ensure that aspiration pneumonia or other respiratory concerns that would cause complications during anesthesia are under control. Your veterinarian will also recommend that your dog fast prior to surgical procedure. Because the oronasal fistula closure procedure is located in the oral cavity, general anesthesia may be administered by intravenous rather than by intubation tube. 

Once your dog is under anesthesia your veterinarian will excise any damaged tissue and repair the oronasal fistula. Repair is usually conducted by harvesting mucogingival flaps in the oral cavity and suturing over the gap. This is done by making incisions in the surrounding tissue to acquire appropriate sized healthy skin flaps that can be used to cover the fistula. Either a single or double layered flap may be used depending on tissue availability and size and condition of the gap requiring closure. Flaps selected need to have the maximum amount of blood supply and be large enough to cover the fistula. The edges of the flap and the defect must be free of epithelium and granulated tissue in order to allow for sutured edges to adhere. Minimum tension is used on the suture line and the repair flap is preferably sutured over health bone and tissue. Once the repair of the fistula is complete your dog will be put into recovery for anesthetic to wear off.

Oronasal fistulas are prone to flap dehiscence. This occurs when the suture line ruptures. If surgical precautions are taken to allow maximum blood supply, suture lines are created over bone, and tension-free sutures are used, the incidence of this is greatly reduced and the successful closure of oronasal fistula is likely to be achieved. Closure of the fistula will eliminate the communication between the oral and nasal cavities and prevent further inhalation of food and water, however damage done to the respiratory tract may still need addressing and may be chronic.

After surgery your dog will require painkillers and antibiotics as prescribed by your veterinarian. They should be fed only soft food for three weeks post-surgery and all chew toys or objects that your dog may put in their mouth should be removed. You will need to monitor your dog to ensure they do not chew on anything or paw at their face or mouth, which could cause damage to the surgical repair. A basket muzzle may aide in this.

Repair of oronasal fistula in your dog, including anesthesia and medications, range in cost from $200 to $500 depending on the extent of the repair and cost of living in your area.

If respiratory infection is present, the condition can be chronic depending on the extent of damage sustained in the respiratory tract and fistula repair will not address this. As well, respiratory compromise greatly increases the risk from administration of anesthetic. The main complications with closure of oronasal fistula is wound dehiscence. Applying surgical techniques appropriate to this procedure will reduce the likelihood of suture rupture.

Ensuring your dog receives early and appropriate dental care will reduce the likelihood of oronasal fistula occurrence. Veterinary care to monitor for periodontal disease, routine dental radiographs to detect dental problems early, and prompt attention to dental issues will prevent periodontal disease from damaging underlying tissues and structures. Regular cleaning of your dog's teeth will also help prevent periodontal disease. When extractions are required, avoiding oronasal fistulas can be accomplished by ensuring that extraction sites are closed rather than waiting for healing to occur naturally by granulation, as this is not effective. Repair of extraction sites with muscogingivival flaps at the time of extraction will prevent later repair after respiratory compromise has already occurred.

In addition, ensure that there are no hazardous objects available to your dog that they may chew on and cause oral trauma.