ABSTRACT
To evaluate Dermatomal Somatosensory evoked potentials [DSEPs] as an objective test for detection of sensory compromise and segmental affection of sensory roots in lumbar spinal canal stenosis. 25 patients with LSSS and candidate for decompressive surgery were recruited for the study. They were diagnosed by clinical and radiological criteria. 10 healthy subjects were concluded as a control group. SEPs and DSEPs were done preoperatively and 3 months postoperatively. There was a significant difference between patients and controls as regard DSEPs latencies [p<0.05] while there was no significant difference between the two groups as regard DSEPs amplitudes. There was statistically significant difference between preoperative and 3 month postoperative DSEPs latencies [p<0.05]. There was statistically significant difference between preoperative and postoperative functional scores [p<0.05]. Sensitivity of DSEPs was 92%.The results of this study showed that DSEPs is a sensitive test and complementary to the radiological investigations providing information about the electrophysiological function of lumbosacral roots and the level of root compression. It is also non-invasive easy test