Selection Bias in Avoiding Vein Graft in Replantation/Revascularization May Exist in Distal and Proximal Amputations, Respectively

Abstract

Background: No difference in the success rate has been reported between the vein graft and non–vein graft groups in replantation/revascularization. However, this depends on a wide range of indications in difficult cases. This study aimed to investigate the selection bias in avoiding vein grafts. Methods: This is a single-center, noninterventional, retrospective cohort study comprising 229 patients (277 digits) who underwent replantation/revascularization between January 2000 and December 2020 at our institution. Sex, age, smoking history, comorbidities, affected side, level of amputation, complete or incomplete amputation, type of fracture and mechanism, diameter of the artery, needle, warm ischemic time, and results were investigated and compared between the subgroups with and without vein graft. Results were investigated between the subgroups with and without a vein graft in the distal and proximal groups. Results: In the distal group, the mean arterial diameter of the vein graft subgroup was larger than that of the non–vein graft subgroup [0.7 (0.1) mm and 0.6 (0.2) mm, respectively, P < 0.05]. In the proximal group, the vein graft subgroup had higher severity than the non–vein graft subgroup (comminuted fracture, 31.1% versus 13.4%; and avulsion or crush amputation, 57.8% versus 37.1%, respectively, P < 0.05). However, the success rate was not significantly different between the aforementioned subgroups. Conclusion: There was no significant difference between the vein graft and non–vein graft subgroups owing to the selection bias avoiding small arteries in the distal amputation and the absence of said bias in the proximal amputation.

Success Rates of Finger Revascularization and Replantation

“…This also indicated that the severity of the proximal revascularization subgroup was similar to or greater than that of the replantation subgroup. 16 This finding also indicated that there was no bias in avoiding severe cases within the proximal revascularization subgroups.…”

“…Kobayashi et al reported that cohorts of amputations having a higher frequency in applying vein grafts include more severe cases. 16 This suggests that the severity in the revascularization subgroup was either similar to or greater than that in the replantation subgroup. It also indicated that there was no bias in avoiding severe cases in the distal revascularization subgroup.…”

“…The severity of the injury was lower in the distal amputation group than that in the proximal amputation group, possibly because the arteries of the amputated digit were severely damaged or too short to be identified, secured, or anastomosed in severe cases of the distal amputation group. 16 We assumed that cases with severe damage may have been excluded by amputation plasty. 16 It was hypothesized that potential selection bias in avoiding distal arterial anastomosis could be attributed to smaller arterial diameters.…”

“… 16 We assumed that cases with severe damage may have been excluded by amputation plasty. 16 It was hypothesized that potential selection bias in avoiding distal arterial anastomosis could be attributed to smaller arterial diameters. However, in the proximal amputation group, it could be associated with multiple amputations and the severity of injuries.…”