Comparison of hand responses to recipient nerve stimulation in sequential variations of supercharged anterior interosseous nerve transfer to the ulnar nerve - Identifying the golden recipient fascicles.

Abstract

In supercharged end-to-side (SETS) anterior interosseous nerve (AIN) transfer for compressive ulnar neuropathy, selecting the optimal recipient fascicle remains challenging owing to weak or absent motor responses. We hypothesized that modifying the procedural sequence would improve intraoperative nerve responsiveness, thereby enhancing the identification of recipient fascicles in the thumb, 4 digits, and hypothenar muscles (3 target muscle groups). We retrospectively reviewed 52 patients who underwent SETS AIN transfer from 2019 to 2024. Group 1 (n = 25) followed this sequence: Elbow decompression-Guyon's canal release-preparation of the recipient ulnar nerve-donor harvest-coaptation of AIN to the ulnar nerve. Group 2 (n = 27) followed: Guyon-recipient-donor-elbow-coaptation. Intraoperative responses to ulnar nerve stimulation were categorized into 3 muscle groups and graded as "Definitive"-(2), "Trace"-(1), or "No response"-(0). Tourniquet time was recorded during recipient stimulation. Demographics and preoperative clinical status did not differ significantly between the groups. However, tourniquet time was significantly shorter in Group 2 (P < 0.05). Group 2 also demonstrated significantly higher responsiveness scores across all the 3 muscle groups (P < 0.05). When analyzing all the cases, responsiveness in the thumb and 4 digits was significantly associated with total grip strength, key and oppositional pinch strength, specific ulnar-innervated muscle strength, and tourniquet time (P < 0.05). For hypothenar responsiveness, only tourniquet time was a significant factor. Optimizing the procedural sequence in SETS AIN transfer enhances intraoperative nerve responsiveness, particularly when "Guyon's canal release-preparation of the recipient" precedes "elbow decompression". This approach facilitates more accurate fascicle selection and may improve surgical outcomes. A retrospective comparative study.