PURPOSE: Perforator flaps have become widely used in plastic surgery. Anatomically, perforators have a gradual reduction in the vessel caliber as they run towards the periphery. During free flap elevation, temporary or prolonged vascular spasms can be appreciated, resulting in a momentary decrease in pulsation. This phenomenon, unless resolved, can result in postoperative flap failure. Usually, intraoperative topical application of papaverine hydrochloride and/or warm water are sufficient to restore normal blood flow. Nevertheless, due to lack of reliable assessment modalities (e.g., macroscopic observation, loupe, or palpation), resolution of the spasm and recovery of pulsation at the periphery of perforators cannot be determined in a judicious and objective manner. The purpose of this study was to use the new generation video-capillaroscopy to evaluate and analyze the pulsation of perforators and observe circulation at the end of branches with a diameter even in ≦ 0.01-mm in adipose tissue during flap elevation.
METHOD: Between November 2021 and February 2022, seven free flaps (two rectus abdominis flaps and 5 anterolateral thigh flaps) for head and neck reconstruction were evaluated with video-capillaroscopy (Bscan-ZD, GOKO Imaging Devices Co., Ltd., Japan). The visual field of video-capillaroscopy was about 175x and 620x, 1.2 million pixels, and 1-mm depth from the surface. The type of perforator spasm after flap elevation was divided into 6 types according to the video-capillaroscopy findings. No spasm/decreased pulsation (S/DP) (type A); S/DP with recovery within 5 minutes (type B); S/DP requiring papaverine hydrochloride spraying (PHS) and hot water treatment (HWT), resulting in recovery within 5 minutes (type C); S/DP requiring PHS and HWT resulting in recovery within 10 minutes (type D); S/DP requiring PHS and HWT resulting in recovery within 15 minutes (type E); S/DP with no recovery on pulsation following PHS and HWT (type F).
RESULTS: Twenty-five perforators were evaluated. Using our classification for perforator vessel spasms on video-capillaroscopy, observations of five perforating branches were classified as Type-A, seven as Type-B, six as Type-C, five as Type-D, and two as Type-E. No Type-F spasms were observed. Real-time movement of red blood cells in adipose tissue and pulsation could be observed in perforator’s branches with a minimum diameter of 0.007 mm. Vascular pulsation with sinus rhythm could be observed on the imaging monitor. The absence/presence of pulsation made it possible to determine the alignment of the artery and vein.
CONCLUSION: During microvascular reconstruction, it is imperative that blood flow from perforating vessels is stable with resolution of S/DP before the pedicle vessel is cut and anastomosis is performed. In some instances, vascular damage during flap harvest and perforator dissection can cause interruption of blood flow to the periphery via different mechanisms. With video-capillaroscopy it is possible to confirm if blood flow deterioration occurs even in areas that are difficult to observe macroscopically. Video-capillaroscopy, a non-invasive imaging modality, is a useful alternative for the intraoperative evaluation of perforator flow and safe flap elevation and transfer.