Patency Test of Vascular Anastomosis with Assistance of High-Speed Video Recording in Digit Replantation

Background: Quality assessment of vascular anastomosis primarily depends on the experience of the treating surgeon. This highlights the need for an objective index. The main goal of our study was to establish a method of assessing the quality of vascular anastomosis in digit replantation. Methods: A total of 182 digits from 141 patients were included in this study. The patients underwent replantation of completely amputated digits between June 1, 2015, and February 1, 2017. Patency tests of arterial and venous anastomoses were conducted for each replantation and recorded on digital video at 1,000 frames per second. We divided the study into 2 phases. In phase I (103 digits from 80 patients), we investigated whether the refilling velocity ratio (RVR) was associated with replantation failure. In phase II (79 digits from 61 patients), we adopted the RVR as a guiding parameter during surgery and compared the replantation success rate with that of the historical control of phase I. Results: In phase I, ischemia time (>12 hours), arterial RVR (<0.4), and venous RVR sum (<1.0) were significantly associated with the rate of replantation failure in 82 cases with single arterial anastomosis. In phase II, we set the arterial RVR goal to 0.4 and venous RVR sum goal to 1.0. Under the guidance of the RVR test, the survival rate significantly increased compared with that of the historical control of phase I (96% versus 87%; p = 0.037). Conclusions: The patency test, with assistance of high-speed video recording, is a useful tool that can improve the success rate of digit replantation.