Free functional musculocutaneous transfer: electrophysiological studies.

Transplanted autogenous muscles were electrophysiologically studied in 2 patients with forearm crush injury. Only fibrillation action potentials and positive sharp waves were seen at 1 month after the operation. Low-amplitude and short-duration muscular unit potentials (MUPs) appeared at 3 months and high-amplitude, long-duration and polyphasic MUPs were frequently seen at 6-7 months after the transplantation. The distal latencies of the evoked motor responses were gradually shortened from time to time and eventually became normal at about 1 year after the grafting. The mean consecutive difference became normal at about 6 months after the normalization of the distal latencies. We conclude that the motor endplate is functionally completed at about half a year after the completion of the myelination of the grafted nerve.