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Oroantral fistula

Oroantral fistula:
This is a fistulous communication between the floor of the maxillary sinus to the oral cavity. This commonly occurs following dental extraction of infected upper molar and premolar tooth.

The upper lateral teeth when removed has a tendency to form blood clots. Fibrosis sets in within the clot material aiding the healing process. Fibrosis inside the clot is the most critical stage in the healing process. During this process of healing the air pocket within the maxillary sinus could keep constantly extruding hampering the healing process. This eventually leads to the formation of oroantral fistula. In order to prevent this fistula formation the mucosal flaps after extraction of upper lateral teeth should be sutured.

Clinical features:
1. Patients manifest with signs and symptoms of maxillary sinus infections.
2. Purulent discharge could be seen from the middle meatus
3. History of dental extraction - positive
4. Fistulous communication could be seen within the oral cavity through which pus could be seen extruding

Valsalvin test: This is confirmatory test for the presence of oroantral fistula. This test is performed by asking the patient to blow air through the nose after pinching the nose closed. The patient must keep the mouth open. The air could be heard hissing out of the fistula. This test could be negative in some patients in whom oedematous middle ear mucosa occludes the fistula (false negative).
Probe test: using a blunt probe, an attempt should be made to probe the suspected fistulous area.

1. X ray para nasal sinuses water's view shows haziness of the involved maxillary antra.
2. CT scan of para nasal sinuses is diagnostic. The defect can be clearly seen ion the bone window cuts.

CT scan showing hazy antrum with bone defect showing the fistula

1. Wait and watch approach: A significant amount of these fistulas tend to heal spontaneously. This is more so if the size of the fistula is 2 mm or less. If the size is 3 mm or more then spontaneous healing is hampered because of sinus infection in the periodontal area.
2. Caldwel Luc procedure: This surgery aims at creating a more permanent drainage via the antrostomy performed through the inferior meatus. This helps in spontaneous healing of the fistula.
3. Direct closure of the fistula can be attempted using palatal flaps.

Balasubramanian Thiagarajan,
Jun 10, 2008, 4:49 AM