Drain fluid amylase as a predictor of postoperative salivary fistula in cases with benign parotid tumours

BACKGROUND: Late diagnosis of a salivary fistula increases the risk of wound infection and scarring. The purpose of the present study was to identify a quantitative predictor of postoperative salivary fistula for cases treated with surgery. METHODS: Demographic, intraoperative and postoperative parameters for 57 cases that received surgery for benign parotid tumours were recorded from June 2017 to June 2018, of which 18 cases developed salivary fistulas. These data were analysed using univariate and binary logistic regression analyses as well as receiver operating curve analysis. RESULTS: Drain fluid amylase concentration was positively correlated with salivary fistula development (p < 0.001), with an odds ratio of 1.14 for a 1 KU/L increase in concentration and an optimal receiver operating curve cut-off value of 51,100 U/L for predicting salivary fistula development. Cases wherein the parotid–masseteric fascia remained intact were associated with a lower risk of salivary fistula development (p = 0.006). CONCLUSION: Drain fluid amylase concentration may be a valuable predictor of postoperative salivary fistula in cases with benign parotid tumours.