Intraoperative flap perfusion of radial free forearm flaps is associated with postoperative flap revision in microvascular head and neck reconstruction: a retrospective cohort study.

BACKGROUND: Postoperative vascular flap compromise continues to occur in microvascular head and neck reconstruction, requiring time-consuming postoperative flap monitoring. This study assessed the association between intraoperative flap perfusion and postoperative flap revision. METHODS: Flap perfusion measurement data collected intraoperatively with the Oxygen-2-see analysis system from 296 patients reconstructed with a radial free forearm flap in the head and neck region between 2011 and 2022 were retrospectively analyzed. Intraoperative flap blood flow, hemoglobin concentration, and hemoglobin oxygen saturation at 8 and 2 mm tissue depth were compared between patients without and with postoperative flap revision and cut-off values predicting postoperative flap revision were determined. RESULTS: Intraoperative flap blood flow and hemoglobin oxygen saturation were lower and hemoglobin concentration was higher in patients with postoperative flap revision compared to patients without postoperative flap revision at 8 mm tissue depth [82.0 arbitrary units (AU) vs. 132.0 AU, p<0.001; 67.0% vs. 79.0%, p = 0.006; and 53.0 AU vs. 45.0 AU, p = 0.025]. The related cut-off values predicting flap revision for flap blood flow, hemoglobin concentration, and hemoglobin oxygen saturation were <82.5 AU, >51.5 AU, and <78.5% (sensitivity 56%, 56%, and 78%; specificity 90%, 69%, and 52%). CONCLUSIONS: Intraoperative flap perfusion was associated with postoperative flap revision, with cut-off values predicting postoperative flap revision determined as minimum blood flow and hemoglobin oxygen saturation and maximum hemoglobin concentration values. These findings should be confirmed in further studies to support the implementation of prevention strategies such as intraoperative anastomosis check and closer postoperative flap monitoring for flaps at risk.