Anterior Interosseous–to–Ulnar Motor Nerve Transfers: A Single Center’s Experience in Restoring Intrinsic Hand Function

Abstract

Background: Transfer of the anterior interosseous nerve (AIN) into the ulnar motor branch improves intrinsic hand function in patients with high ulnar nerve injuries. We report our outcomes of this nerve transfer and hypothesize that any improvement in intrinsic hand function is beneficial to patients. Methods: A retrospective review of all AIN-to-ulnar motor nerve transfers, including both supercharged end-to-side (SETS) and end-to-end (ETE) transfers, from 2011 to 2018 performed by 2 surgeons was conducted. All adult patients who underwent this nerve transfer for any reason with greater than 6 months’ follow-up and completed charts were included. Primary outcome measures were motor function using the British Medical Research Council (BMRC) grading system and subjective satisfaction with surgery using a visual analog scale. Secondary outcome measures included complications and donor site deficits. Results: Of the 57 patients who underwent nerve transfer, 32 patients met the inclusion criteria. The average follow-up and average time to surgery were 12 and 15.6 months, respectively. The overall average BMRC score was 2.9/5, with a trend toward better recovery in patients who received earlier surgery (<12 months = BMRC 3.7, ≥12 months = BMRC 2.2; P < .01). Patients with an SETS transfer had better results that those with an ETE transfer (SETS = 3.2, ETE = 2.6). There were no donor deficits after operation. One patient developed complex regional pain syndrome. Conclusions: Patients with earlier surgery and an in-continuity nerve (receiving an SETS transfer) showed improved recovery with a higher BMRC grade compared with those who underwent later surgery. Any improvements in intrinsic hand function would be beneficial to patients.

Anterior Interosseous Nerve to Ulnar Nerve Transfer: A Systematic Review

“…A single study 7 was unique because it directly compared ETE transfer against SETS transfer through a retrospective cohort in patients with ulnar nerve compression at the elbow. Results are presented separately and were not pooled.…”

“…Pre-operative (p). Study No of Transfers Age M:F Type of Injury Location of Injury Symptom Duration pWeakness pNumbness pPain pAtrophy pPositive Froment's Sign McLeod 7 32 15 ETE 17 SETS 58.3 25:7 32 compression 32 elbow 15.6 months 15 32 NR 32 15 …”

“…Complex regional pain syndrome (CRPS) and no result (NR). Study Follow-up (months) Time to nerve transfer Intrinsic recovery from symptom onset to surgery Time to recovery(months) ETE intrinsic recovery from symptom onset to surgery SETS intrinsic recovery from symptom onset to surgery Complications McLeod 7 12 15.6 months Overall BMRC = 2.9 <12 months BMRC = 3.7 ≥12 months BMRC = 2.2* SETS BMRC = 3.2 ETE BMRC = 2.6 NR <12 months BMRC = 3.4 ≥12months BMRC = 1.9 <12 months BMRC = 4.0 ≥12 months BMRC = 2.6 1 CRPS …”

“…The study by McLeod et al. 7 was unique because it directly compared the results of ETE and SETS in patients with ulnar nerve compression at the elbow. The overall post-operative BMRC score was 2.9 amongst both interventions.…”

“…A further subgroup was included since a single study directly compared outcomes of end-to-side versus SETS AIN transfer in patients with compressive ulnar nerve neuropathies at the elbow. 7 …”