[Clinical study of cervical radiculopathy after laminoplasty for cervical myelopathy]

We have retrospectively determined the preoperative risk factors in cervical radiculopathy after laminoplasty for cervical myelopathy using preoperative neuroradiographical findings and electrophysiological studies. Of the 67 patients who underwent laminoplasty, 10 patients (14.9%) postoperatively showed cervical radioculopathy. The preoperative radiographical findings had included cervical lordosis, intraspinal cord centering, and anterior protrusion of the apex of the superior articular process. Needle electromyography, somatosensory evoked potentials (SEPs), sensory nerve action potentials (SNAP) were preoperatively examined in 42 cases. There was no relationship between the postoperative radiculopathy and the preoperative radiographical findings. Six (100%) of 6 cases preoperatively diagnosed as C5 radiculopathy (postganglionic type) with Erb-P 14 interpeak latency of dermatomal SEPs and SNAP, developed postoperative C5 radiculopathy. One (25%) of 4 cases preoperatively diagnosed as C6 radiculopathy developed postoperative C6 radiculopathy. No case preoperatively diagnosed as C7 or C8 radiculopathy developed postoperative radiculopathy. This study suggested that an important risk factor for postoperative radiculopathy was subclinical C5 radiculopathy (postganglionic type) that could be preoperatively evaluated using electrophysiological studies.