Investigation of Predictors of Successful Replantation of Distal Digits at the Nail Bed Level: The Contribution of Digital Nerve Repair to Survival Rate

Background: Replantation of amputated digits at the nail bed level is surgically challenging and differs from replantation at a more proximal amputation level. This study aimed to determine the predictors influencing the success rate of fingertip replantation. Methods: Overall, 239 digits of 226 patients who underwent replantation surgery from August of 2009 to March of 2020 were considered. A total of 15 independent variables (i.e., sex; age; injured hand; digit; history of smoking; history of hypertension or diabetes; injury mechanism; amputation level; ischemia duration; surgeon's expertise; numbers of repaired arteries, veins, and nerves; and the need for a vein graft) were investigated for their effects on the survival of the replanted digits. Results: Of all 239 digits, 190 (79.3 percent) survived. Univariate analysis indicated that non-crush-avulsion injury, expertise and experience of the surgeon, vein repair, and nerve repair contributed to increasing the survival rate. Binary logistic regression analysis demonstrated that injury mechanism, vein repair; and nerve repair were significant predictive factors. in addition, in non-vein-repaired, blunt cut, or Ishikawa subzone II cases, digital nerve repair contributed significantly to promote the success rate relative to vein-repaired, crush-avulsion-type injury, and subzone I cases. Conclusions: Vein repair, nerve repair, non-crush-avulsion injury, and surgeon's expertise and experience were the predictors for successful replantation. Intraoperative vein and nerve repair are recommended to improve the survival rate of fingertip replantation at the nail bed level.