Spinal cord monitoring for scoliosis surgery in Rett syndrome: can these patients be accurately monitored?

STUDY DESIGN A level III retrospective comparative study. OBJECTIVE Assess the clinical efficacy of somatosensory-evoked potential (SSEP) spinal cord monitoring (SCM) in Rett syndrome patients undergoing scoliosis surgery. SUMMARY OF BACKGROUND DATA The role of SCM in neuromuscular scoliosis is less accurate compared with idiopathic scoliosis because of the nature of the neuropathic or myopathic disorder. Currently, there are no studies that have specifically addressed the accuracy of SCM in Rett syndrome. METHODS A retrospective study to assess the clinical efficacy of SSEP SCM in Rett syndrome patients undergoing scoliosis surgery. Somatosensory-evoked potentials were monitored in 7 patients (8 procedures) with Rett syndrome undergoing scoliosis surgery. Transcranial motor-evoked potentials were not performed because of a concomitant history of seizures. The specific methods of anesthesia and SSEP monitoring were standardized for all patients. RESULTS Adequate baseline and intraoperative SSEP measurements could be obtained in all patients. There were no false-negative or false-positive results. There were 7 true-negative and 1 true-positive results during surgery. The latter was a signal amplitude decrease that did not immediately resolve with standard interventions. Consequently, a Stagnara wake-up test was performed that showed spontaneous muscle activity in both lower extremities. No intravenous steroids were given, and the procedure was completed. The patient had transient unilateral lower extremity motor weakness postoperatively, but recovered preoperative muscle function within 24 hours. CONCLUSIONS Patients with Rett syndrome undergoing scoliosis surgery can be successfully monitored with SSEPs. A history of seizures is a relative contraindication to transcranial motor-evoked potentials. Monitoring can accurately alert the surgeon to potential intraoperative spinal cord compromise and, therefore, decrease postoperative morbidity.