Modern Nerve Surgery Applied to Biopsy Evaluation for Neuromuscular Disorders.

PURPOSE: Expendable nerves commonly used in nerve transfer surgery may serve as options for diagnosing peripheral neuropathies, potentially improving outcomes compared to traditional sural nerve biopsies. This study compares diagnostic utility of sural nerve biopsies versus other nerve biopsies and evaluates patient-reported postoperative pain following sural nerve biopsy with allograft reconstruction. METHODS: A retrospective review of patients undergoing diagnostic sural or other nerve ± muscle biopsies at a quaternary referral center from January 2020 to July 2025 was conducted. Patient demographics, biopsy sites, and diagnostic outcomes were recorded. Chi-square test assessed association between biopsy site and diagnostic utility. Patients who underwent sural nerve biopsy were called at a median 706 (481, 1192) days after surgery regarding new pain at the biopsy site. Significance was set at p <  0.05. RESULTS: Among 97 patients (57.7% male; median age 67 (58, 73) years), 108 nerves and 103 muscles were biopsied. Common non-sural nerve biopsies included the anterior interosseous nerve (AIN) (13.0%), palmar cutaneous nerve (3.7%), and nerve to flexor digitorum superficialis (3.7%). A confirmed diagnosis was noted by the referring neurologist in 77% of sural biopsies, 79% of AIN biopsies, and 94% other nerve biopsies (p =  0.308). Thirty-four out of 37 (91.9%) patients reported no new pain at the sural biopsy site. CONCLUSION: In this study, the diagnostic utility of sural nerve biopsies exceeds existing literature and compares to other nerve biopsies. Expendable nerves may serve dual roles as donors for nerve transfer and targets for diagnostic biopsy. Moreover, standardized allograft reconstruction may reduce postoperative pain.