A Comparison of the Use of Branch to Brachialis vs. Branch to Extensor Carpi Radialis Brevis in the Transfer to Anterior Interosseous Nerve in Spinal Cord Injury: A Systematic Review

Introduction: Nerve transfer involves the delivery of a functional donor nerve to a lesioned recipient nerve and is increasingly utilized in the treatment of spinal cord injury (SCI). There is a dearth of large-scale data on the effectiveness of specific transfers in this patient population. This review seeks to compare the effectiveness of two different donor nerves, branch to brachialis and branch to extensor carpi radialis brevis (ECRB), in the transfer to anterior interosseous nerve (AIN) in SCI patients.

Methods: A systematic review was conducted using the PubMed, Google Scholar, and ScienceDirect databases to identify studies that observed either branch to brachialis or branch to ECRB in the transfer to AIN in SCI patients with adherence to PRISMA guidelines. Studies with post-operative medical research council (MRC) scores for finger flexion were included. Data was extracted, aggregated, and analyzed using a random effects model on a computer software.

Results: The initial search yielded 250 articles of which 16 were extracted and included in the final analysis. This included 90 branch to brachialis to AIN transfers with an average postoperative MRC score of 2.23. 14 branch to ECRB to AIN transfers were included with an average postoperative MRC score of 4 and no variance. In analysis with a two-sample t-test, ECRB to AIN transfers demonstrated a significantly higher MRC score (M = 2.233, SD = 1.272439044) than brachialis to AIN transfers (M = 4, SD = 0); t(89) = 13.17, p < 0.05.

Conclusion : The use of the branch to ECRB as the donor nerve as compared to the branch to brachialis in the transfer to AIN offers increased MRC scores in SCI patients. The use of the branch to ECRB as a donor nerve for the sake of improving finger flexion in SCI is supported by the current literature.