Nerve conduction study in cervical spinal cord injury: significance for hand function

Examination of hand function and nerve conduction study of median and ulnar nerves was performed in 15 patients with acute and 26 patients with chronic tetraplegia due to cervical spinal cord injury (SCI). Thirty percent of patients showed a mild and 20% a severe axonal lesion of motor fibres of both nerves. The latter can be attributed to an intramedullary damage of ventral horn cells and anterior nerve roots, as the examination of sensory nerve fibres were normal in these patients. By median and ulnar nerve conduction study in tetraplegic patients with paresis of intrinsic hand muscles, it was possible to differentiate between a predominant damage of ventral horn cells/anterior nerve roots (peripheral nervous system) and of pyramidal tract fibers (central nervous system) responsible for the paresis. The extent of motor nerve lesion depended upon the level of SCI and was most frequent and severest in lower cervical spinal cord injuries (C6-T1), where median and ulnar nerves originate. In the latter patients the development of an active hand function, which enables the patient to perform active grasping movements, was closely related to the result of motor nerve conduction study, already early after trauma. Therefore, this technique can be of prognostic value in cervical SCI to predict the outcome of hand function and to allow an early selection of the appropriate occupational therapy in tetraplegic patients.