Functional recovery after ventral root avulsion and implantation in the spinal cord.

This survey describes experiments performed in rats, cats and monkeys aiming at the management of motor deficits after ventral root rupture or avulsion from the spinal cord as seen in brachial plexus lesions. After intramedullary implantation of the ruptured or avulsed ventral root, neurophysiological data show that alpha and probably also gamma motoneurons are capable of producing new axons which regrow for a considerable distance in the spinal cord before entering the implanted root. Intracellular physiological experiments demonstrate that new axons can conduct action potentials and elicit muscle responses. The neurons are reconnected in segmental spinal cord activity and respond to impulses in sensory fibres. In primates, implantation of avulsed ventral roots in the brachial plexus resulted in functional restitution. It is concluded that intraspinal implantation of avulsed ventral roots significantly promotes motor recovery in the muscles supplied by the lesioned spinal cord segments. These studies indicate the possibility of surgical treatment of ventral root avulsion injuries in brachial plexus lesions in man.