Individualization of Donor Nerve Selection With Intraoperative Nerve Monitoring in Axillary Nerve Neurotization.

Purpose: This study aimed to evaluate the use of intraoperative nerve conduction studies in radial to axillary nerve transfers using the motor branches to the triceps. We hypothesized that morphological characteristics might not fully express a donor nerve's suitability for transfer and that choosing the donor branch based on nerve action potential (NAP) amplitudes would lead to better functional outcomes. Methods: This retrospective analysis included 17 patients who underwent radial to axillary nerve transfer. The specific triceps motor branch used as donor and the site of neurorrhaphy were chosen based on intraoperative NAP amplitudes independently of morphological criteria, such as size matching or arc of rotation. Results: We found a moderate correlation between the NAP amplitude of the transferred branch and shoulder abduction strength at the end of the follow-up. The branch to the lateral head of the triceps was the most often selected as a donor. Outcomes were satisfactory in 14 out of 17 patients. Conclusions: The findings suggest that reinnervation is enhanced when the choice of the donor branch is individualized and based on functional metrics like NAP, instead of anatomical characteristics. The study supports the role of intraoperative nerve monitoring as an objective and predictable method to refine donor branch selection in radial to axillary nerve transfer. Type of study/level of evidence: Therapeutic IV.