Supinator to Posterior Interosseous Nerve Transfer to Restore Hand Opening in Brachial Plexus and Spinal Cord Injury: a Systematic Review and Individual-Patient-Data Meta-analysis

Introduction: Cervical spinal cord injury (SCI) and lower trunk brachial plexus injury (BPI) commonly result in hand paralysis. While restoring hand function is complex and challenging to achieve, regaining volitional hand control drastically enhances functionality for these patients. We aimed to systematically review outcomes of hand opening function after a supinator to posterior interosseous nerve (PIN) nerve transfer.

Methods: A systematic literature review was performed according to the PRISMA guidelines.

Results: A total of 16 studies with 88 patients and 119 supinator to PIN transfers were included (87 for SCI; 32 for BPI). In most of the studies the time interval from injury to surgery was 6-12 months. Finger extension and thumb extension (MRC ≥3/5) recovered in 86.5% (n:103/119) and 78.1% (n:93/119) of cases, respectively over a median follow-up of 19 months. The rates of recovery were similar for the SCI and BPI populations (finger extension: 87.3% in SCI and 84.3% in BPI; thumb extension: 75.8% in SCI and 84.3% in BPI). The type of injury (OR: 1.05; 95% CI: 0.17-6.4; p=0.95) and time from injury to surgery (OR: 1.01; 95% CI: 0.8-1.29; p=0.88), age (OR: 0.97; 95% CI: 0.90-1.06; p=0.60) were not associated with the odds of a successful outcome. Duration of follow-up was statistically significant associated with successful finger extension (OR: 1.15; 95% CI: 1.01-1.30; p=0.026). No donor-associated supinator weakness was reported post-operatively given patients had an intact bicep muscle pre-op contributing to supination.

Conclusion : Supinator to PIN transfer is a safe and effective procedure that can achieve successful restoration of digital extension in the SCI and BPI population at similar rates. Duration of follow-up of follow-up was associated with superior outcomes which is expected.