Routine preoperative MRI and SEP studies in adolescent idiopathic scoliosis.

In this prospective study, 72 patients with the clinical diagnosis of adolescent idiopathic scoliosis underwent routine preoperative magnetic resonance imaging (MRI) scans and neurologic consultations. Forty-eight patients also had preoperative somatosensory evoked potentials (SEPs). All patients had normal neurologic examinations. Abnormal findings included two patients with Chiari type I malformation and one with a finding of a fatty collection in a vertebral body. In four cases, interpretation of the MRI was suspicious or equivocal, necessitating a computed tomography myelogram or other additional studies for clarification. Abnormal preoperative SEP results were obtained in three patients, none of which proved significant. All surgical patients underwent instrumentation and fusion without incident. The results indicate that routine preoperative SEP is not necessary. Routine preoperative MRI is probably not indicated in adolescent idiopathic scoliosis if the patient has a normal neurologic examination.