A TECHNIQUE TO QUANTITATE MOTOR RECOVERY FOLLOWING NERVE GRAFTING

Sixteen patients were evaluated retrospectively following grafting of an upper extremity peripheral nerve injury. In addition to the standar d subjective muscle grading, the force of reinnervated muscle groups w as quantitatively measured using force transducers, and reported relat ive to the contralateral side. Patients recovered a median motor grade of M3, which correlated to a 32% recovery of muscle force of the cont ralateral side. M3 and M4 motor grades encompassed a large range oi ac tual muscle force: M3 correlated with a recovered force that ranged fr om 17% to 42%, M4 with a range of 66% to 79%. The percent force of mot or recovery decreased significantly with longer delays to nerve grafti ng, even when controlling for the severity of the injury. Similarly, r ecovery of muscle force decreased when longer segments of nerve grafts were used. Testing the return of muscle strength after peripheral ner ve injuries with a standardized objective system that compares functio n to the uninjured side enhances the sensitivity of evaluating nerve r egeneration and provides a measurement system that can facilitate the comparison or different nerve repair techniques.