Effect of salivary fistulas on free flap failure: A laboratory and clinical investigation

Objectives: Infection is associated with free flap failure in patients undergoing microvascular flap reconstruction. This study investigates the association between infection arising from salivary fistulas, microvascular thrombosis, and free flap failure. Study Design: Prospective laboratory investigation and retrospective clinical investigation. Methods: The effect of saliva-induced infection on the patency of microvascular thrombosis was studied in an experimental animal model and in a clinical series of patients undergoing free flap reconstruction of the head and neck. In the laboratory phase of this study, rat femoral artery anastomoses were inoculated with freshly collected rat saliva to simulate a postoperative salivary fistula. The incidence of femoral artery thrombosis was determined. In the clinical arm of this study, the incidence of salivary fistulas and resulting clinical outcome in 588 head and neck free flap reconstructions were examined. Results: In the animal experiment, arterial patency was 95% after 10 days for both the control group and the salivary contamination group. In the clinical series, 24 patients developed salivary fistulas during the postoperative period. No cases of microvascular thrombosis were attributed to salivary fistula formation. Conclusions. Postoperative salivary fistulas do not appear to be strongly associated as a contributory factor toward free flap failure in head and neck reconstruction. On the basis of our current understanding of this condition, we describe a rational approach for management of patients who develop salivary fistulas after microvascular head and neck reconstruction.