What are oronasal or oroantral fistulas? - DVM
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What are oronasal or oroantral fistulas?

DVM InFocus

Diagnosis of fistulas

The clinician may irrigate the suspect lesion and observe the irrigant flow from the ipsilateral nostril. For additional confirmation, fluorescein dye can be infused into the defect with observation for the dye within or emerging from the ipsilateral nostril.

Dental radiography along with periodontal and dental probing should never be omitted. Dental radiographs allow for a general assessment of bone, soft tissues and teeth in the area of a suspect defect. These assessments help in treatment planning for repair of the fistula.

Treatment planning for repair of fistulas

Understanding the client's priorities is fundamental to treatment planning. Ideally, all oral fistulas communicating with the respiratory tract should be repaired. Clear explanations of the benefits and risks associated with repair are needed to obtain informed consent to proceed with treatment.

The size of the defect does matter. The appearance of the soft tissue lesion is typically much smaller than the underlying bony defect. Flap design must be based on the location and the size of the defect. Mucogingival flaps can be single or double layered. The single layer flap is useful in many cases, however the double flap repair can be particularly useful for chronic defects.

Mucogingival flaps must be designed to allow maximal blood supply (tissue perfusion). They must be of sufficient length and width (1.5 to 2 times the defect size) to be tension-free. The connective tissue of the flap must be opposed to connective tissue of the defect. The edges of the defect and the flap should be debrided free of granulation tissue and epithelium. Ideally, the flap should be sutured over healthy bone. The incidence of flap dehiscence is greatly reduced by following these principles; maximum perfusion, overlying bone and tension-free. Flap dehiscence is also minimized by evaluating for, and eliminating occlusal trauma. Clients should withhold hard food and chew toys from the patient for two weeks following surgery, and avoid manipulating the mouth when administering oral medications.


Oronasal and oroantral fistulas are communications between the oral cavity and the respiratory tract. These lesions can occur in both cats and dogs. The cause of these fistulas varies. They are commonly associated with advanced periodontal disease or as complications of dental extraction. Additionally, oronasal or oroantral fistulas can be a result of inherited or developmental defects as seen with a cleft lip or cleft palate. Foreign body penetration, neoplasia or trauma are also potential causes for these defects. Affected patients may or may not demonstrate clinical problems. However, patients that present with a history of chronic sneezing should be suspect for fistulas. Every dachshund should be evaluated regularly for oronasal fistulas using dental radiography and careful periodontal probing due to the particularly high incidence of oronasal fistulas in this breed.

Diagnosis must precede treatment planning for optimal patient care. Oronasal and oroantral fistulas should be treated because appropriate treatment can dramatically improve the quality of life for these animals.


Source: DVM InFocus,
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