Comparison of objective muscle strength in C5-C6 and C5-C7 brachial plexus injury patients after double nerve transfer.

PURPOSE: The purpose of this study was to evaluate the quantitative muscle strength to distinguish the outcomes of different injury levels in upper arm type brachial plexus injury (BPI) patients with double nerve transfer.
METHODS: Nine patients with C5-C6 lesions (age = 32.2 ± 13.9 year old) and nine patients with C5-C7 lesions (age = 32.4 ± 7.9 year old) received neurotization of the spinal accessory nerve to the suprascapular nerve combined with the Oberlin procedure (fascicles of ulnar nerve transfer to the musculocutaneous nerve) were recruited. The average time interval between operation and evaluation were 27.3 ± 21.0 and 26.9 ± 20.6 months for C5-C6 and C5-C7, respectively. British Medical Research Council (BMRC) scores and the objective strength measured by a handheld dynamometer were evaluated in multiple muscles to compare outcomes between C5-C6 and C5-C7 injuries.
RESULTS: There were no significant differences in BMRC scores between the groups. C5-C6 BPI patients had greater quantitative strength in shoulder flexor (P = 0.02), shoulder extensor (P < 0.01), elbow flexor (P = 0.04), elbow extensor (P = 0.04), wrist extensor (P = 0.04), and hand grip (P = 0.04) than C5-C7 BPI patients.
CONCLUSIONS: Upper arm type BPI patients have a good motor recovery after double nerve transfer. The different outcomes between C5-C6 and C5-C7 BPI patients appeared in muscles responding to hand grip, wrist extension, and sagittal movements in shoulder and elbow joints.