Posterior tibial nerve somatosensory cortical evoked potentials in adolescent idiopathic scoliosis

Study Design. Somatosensory-evoked potentials were used to evaluate neurologic function in patients with adolescent idiopathic scoliosis. Objectives. To compare the somatosensory-evoked potentials between patients with adolescent idiopathic scoliosis and healthy control individuals, and to determine the incidence of abnormal somatosensory function in patients with adolescent idiopathic scoliosis. Summary of Background Data. Somatosensory-evoked potentials are sensitive in detecting structural lesions in the somatosensory pathway. Previous studies on somatosensory function in patients with idiopathic scoliosis have demonstrated statistical differences in somatosensory-evoked potential latency between scoliotic and normal groups. However, no documentation of the actual incidence of abnormal somatosensory-evoked potentials is available. Subjects and Methods. Posterior tibial nerve somatosensory cortical evoked potentials were evaluated on 147 young patients with adolescent idiopathic scoliosis and 31 healthy control individuals. Results. Seventeen patients with idiopathic scoliosis showed pathologic evoked potentials. Among them were seven with-absent somatosensory-evoked potential waveform and 10 with delayed latency. The results were reproducible on repeated measurement. Conclusions. Adolescent idiopathic scoliosis could be subdivided according to the somatosensory-evoked potential findings into two subgroups, those with and those without a somatosensory pathologic process. Potential clinical significance in predicting curve progression in idiopathic scoliosis could be pursued further.