Comparison of spinal accessory nerve transfer to supra-scapular nerve vs. shoulder arthrodesis in adults with brachial plexus injury.

BACKGROUND: Restoring shoulder mobility, stability, and strength is a key goal in patients with brachial plexus injuries. Shoulder arthrodesis is chiefly used as an adjunct to, or after failure of, initial direct nerve surgery. The objective of this study was to compare clinical and functional shoulder outcomes after direct nerve transfer vs. shoulder arthrodesis in adults with supra-clavicular brachial plexus injuries. HYPOTHESIS: Shoulder arthrodesis, currently used as a salvage procedure in brachial palsy injuries, deserves to be viewed to a valid alternative to direct nerve transfer. MATERIAL AND METHODS: A retrospective study was conducted in 58 patients with a follow-up of at least 2 years. Among them, 20 were managed by transfer of a spinal accessory nerve fascicle to the supra-scapular nerve and 38 by shoulder arthrodesis. Outcome measures were shoulder range-of-motion, isometric shoulder strength, and the Disabilities of the Arm, Shoulder, and Hand (DASH) score. RESULTS: Mean age at surgery was 24 years and mean follow-up was 46 months (range, 24-156 months). Motion ranges of the shoulder were not significantly different between the two treatment groups. Data variance was significantly greater in the nerve transfer group than in the shoulder arthrodesis group for scapular antepulsion (p=0.0011), abduction (p<0.001), and external rotation (p=0.0066). Strength was significantly greater in the arthrodesis group in all directions of motion. The DASH scores showed no significant between-group differences. CONCLUSIONS: The results of this study conflict with the widely help opinion that nerve transfer to the supra-scapularis nerve produces better clinical outcomes compared to shoulder arthrodesis. Nerve transfer was not better than shoulder arthrodesis in our patients. The data variance heterogeneity suggests poor predictability and reliability of nerve transfer, in contrast to the modest but predictable and uniform results of shoulder arthrodesis. LEVEL OF EVIDENCE: IV, retrospective observational comparative study.

Short- or long-term effects of adult myoblast transfer on properties of reinnervated skeletal muscles.

Skeletal muscle demonstrates a force deficit after repair of injured peripheral nerves. Data from the literature indicate that myoblast transfer enhances recovery of muscle function. Thus, we tested the hypothesis that transfer of adult myoblasts improves the properties of reinnervated rabbit tibialis anterior (TA) muscles in both the short term (4 months) and long term (14 months). Two months after transection and immediate suture of the common peroneal nerve, TA muscles were made to degenerate by cardiotoxin injection and then transplanted with adult myoblasts cultured for 13 days. Under these conditions, muscles studied at 4 months were heavier, contained larger fibers, and developed a significantly higher maximal force than muscles that had only been denervated-reinnervated. In the long term, although muscles made to degenerate were heavier and developed a significantly higher maximal force than denervated-reinnervated muscles, myoblast transfer failed to improve these parameters. However, the overall characteristics of long-term operated muscles tended clearly to approach those of the controls. Taken together, these results may have significant implications in certain orthopedic contexts, particularly after immediate or delayed muscle reinnervation.