CENTRAL MOTOR REORGANIZATION AFTER ANASTOMOSIS OF THE MUSCULOCUTANEOUS AND INTERCOSTAL NERVES FOLLOWING CERVICAL ROOT AVULSION

In 4 patients with a complete upper limb palsy due to traumatic cervic al root avulsion, surgical anastomosis of intercostal to musculocutane ous nerves was performed to restore function in the biceps brachii mus cle. Four to 6 months after the operation, motor unit discharges were recorded from the biceps muscle on the operated side during deep breat hing and by cortical magnetic stimulation. The motor unit discharges b ecame independent from respirations gradually over 1 to 2 years. The l atencies of the motor potentials evoked by cortical and thoracic root magnetic stimulation decreased gradually over 2 to 3 years. Motor cort ex mapping of the reinnervated biceps muscle showed a gradual change o ver 4 to 33 months from the area of the intercostal muscles to that of the arm area, which was more lateral on the motor cortex. These findi ngs suggest that reorganization of the motor cortex to arm flexor musc les occurs following peripheral nerve anastomosis.