[Electrophysiologic analysis of the lumbosacral radiculopathy using nerve root conduction velocity (NRCV) and cauda equina action potentials (CEAP)].

Nerve root conduction velocity (NRCV) and cauda equina action potential (CEAP) have been measured to assess the severity of lumbosacral radiculopathy, the level-specific diagnosis of the symptomatic roots, and to predict the outcome. This study included 71 patients (40 males, 31 females, average age of 54 years at the time of surgery) who underwent decompressive surgery for lumbar radiculopathy. The NRCV and CEAP were directly measured during the operation. The NRCV decreased significantly with progression of radicular symptoms. The NRCV showed a marked reduction in the nerve roots of the patients with a two years or longer history of radicular symptoms; or those with compression of the nerve roots on the imaging examinations; or nerve roots that were considered to have been subjected to persistent compression over a prolonged period with severe inflammation and adhesions. Multivariative analyses suggested that the NRCV correlated closely to the postoperative neurologic recovery, and the outcome of the lumbosacral radiculopathy could be predicted to some extent by measurements of NRCV. The level-specific diagnosis of the radiculopathy could be determined when the CEAP showed a more than 30% left-right potentials difference.