Background: Free flap transplantation is used more and more frequently in order to cover extensive wound defects. The basic prerequisite for successful flap salvage after flap failure is a short time interval from failure until revision. For this reason many different flap monitoring systems have been tested over the last years. But none of them has made the way into clinical routine.
Objective: The aim of this clinical study was to study whether luminescence lifetime imaging (LLI) is an adequate method to assess flap viability during the postoperative period. In previous experiments LLI was proven to be a precise and non-invasive monitoring system for transcutaneous oxygen measurement.
Methods: ptcO2 of 9 patients was detected during a postoperative period of 72 hours. In all cases the transplantation was performed by the same experienced surgeon. During the first 4 hours almost constant ptcO2 values were detected (53±0.7 mmHg). During the following time intervals ptcO2 values decreased and reached a more or less constant level after approximately 12 hours. The mean ptcO2 decreased from 53±0.7 mmHg to 39±1.0 mmHg. In one case an immediate decrease of ptcO2 below 10 mmHg was observed and a subsequently intervention was necessary to improve flap perfusion.
Conclusion: In this clinical trial, perfusion dynamics after free flap transplantation as well as the detection of vascular complications were demonstrated using LLI. Based on these data, LLI seems to be a sensitive and adequate monitoring system for the evaluation of free flap viability.