The use of laser speckle contrast imaging to predict flap necrosis: An experimental study in a porcine flap model.

BACKGROUND: We evaluated the use of laser speckle contrast imaging (LSCI) in the perioperative planning in reconstructive flap surgery. The aim of the study was to investigate whether LSCI can predict regions with a high risk of developing postoperative necrosis. Our hypothesis was that, perioperatively, such regions have perfusion values below a threshold value and show a negative perfusion trend.

METHODS: A porcine flap model based on the cranial gluteal artery perforator was used. Images were acquired before surgery, immediately after surgery (t = 0), after 30 min (t = 30 min), and after 72 h (t = 72 h). Regions of interest (ROIs) were chosen along the central axis of the flap. Clinical evaluation of the flap was made during each time point.

RESULTS: At t = 72 h, a demarcation line could be seen at a distance of 15.8 ± 0.4 cm away from the proximal border of the flaps. At t = 0, perfusion decreased gradually from the proximal to the distal ROI. At t = 30 min, perfusion was significantly lower in the ROI distal to the final demarcation line than that at t = 0, and in all flaps, these ROIs had a perfusion <25 PU. At t = 72 h, perfusion in the ROI proximal to this line returned to baseline levels, whereas perfusion in the distal ROI remained low.

CONCLUSIONS: In our model, a decrease in perfusion during the first 30 min after surgery and a perfusion <25 PU at t = 30 min was a predictor for tissue morbidity 72 h after surgery, which indicates that LSCI is a promising technique for perioperative monitoring in reconstructive flap surgery.