Magnetic stimulation in the determination of lumbosacral motor radiculopathy.

Magnetic stimulation was utilised to diagnose lumbosacral motor radiculopathy non-invasively. Magnetic coil stimulation estimated peripheral motor nerve conduction time (MNCT) which, used in combination with F response, allowed calculation of "motor root conduction time (MRCT)," response being recorded from abductor hallucis. Twenty-five normal controls and 26 patients with lumbar spondylosis were studied. The mean interside difference (left minus right) of MRCT in the control was +0.06 msec (range: -0.88 to +0.74 msec). On clinical and radiological grounds, patients with spondylosis were grouped into those with: (I) no lumbosacral root compression, (II) root compression without motor sign, and (III) root compression with motor deficit. All patients in group III and 36% of cases of group II had MRCT significantly prolonged on the affected side.