Experimental studies on surgical treatment of avulsed spinal nerve roots in brachial plexus injury

This review summarises studies aiming at a surgical treatment of spinal nerve root avulsions from the spinal cord in brachial plexus lesions. After dorsal root injury, regrowth of nerve fibres into the spinal cord occurs only in the immature animal. After ventral root avulsion and subsequent implantation into the spinal cord, neuroanatomical and neurophysiological data show that motoneurons are capable of producing new axons which enter the implanted root. Intra-neuronal 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 nerve fibres. In primate experiments, implantation of avulsed ventral roots in the brachial plexus resulted in functional restitution. These studies indicate the possibility of surgical treatment of ventral root avulsion injuries in brachial plexus lesions in humans.