Efficacy of spinal accessory nerve to suprascapular nerve transfer to restore shoulder function in brachial plexus injury: A systematic review and meta-analysis.

INTRODUCTION: Transfer of the spinal accessory nerve (SAN) to the suprascapular nerve (SSN) is a common surgical intervention employed for restoring shoulder function in both obstetric and traumatic brachial plexus injury (TBPI). Despite widespread use, there is a paucity of evidence surrounding the efficacy of this procedure.

METHODS: A systematic search of the literature in the National Institutes of Health MEDLINE and Embase databases was performed in accordance with the PRISMA guidelines. Patients had to have a minimum postoperative follow-up of 6 months. Cohorts containing patients with obstetric brachial plexus injuries were excluded. We extracted data on shoulder abduction strength, measured using the British Medical Research Council (MRC) scale and range of motion (ROM) of shoulder abduction.

RESULTS: Of the 298 studies screened, 12 with 311 total participants met our inclusion criteria. The average age of participants was 27.03 ± 3.05 years and the male:female ratio was 25.4:1. All patients underwent surgery following TBPI and average time-to surgery was 5.91 ± 1.52 months. 66.37 % of patients achieved a post-operative MRC grade of shoulder abduction of ≥M3 with a mean MRC score of 2.67 ± 1.02. Average post-operative shoulder abduction ROM was 56.97 degrees. Average follow-up time for all reported outcomes was 24.64 ± 7.47 weeks. Nine studies comprising 243 patients were included in the meta-analysis, which revealed a cumulative weighted effect size of 56.83 degrees (95 % CI = 52.31, 61.34).

CONCLUSION: These findings suggest that SAN-SSN transfer is an effective intervention for the restoration of shoulder function following TBPI.