The Utility of Preoperative Neuromonitoring for Adolescent Idiopathic Scoliosis

Background Intraoperative neuromonitoring is well established and widely used to assist in completing corrective surgery for adolescent idiopathic scoliosis (AIS) safely. The role of preoperative measurement of somatosensory evoked potentials (SSEPs) and/or transcranial magnetic stimulation (TMS) to determine if there is transpinal pathology, however, is not clear. We sought to determine if preoperative SSEP and/or TMS measurement provided clinical benefit to patients with AIS.

Methods A review of medical charts between 2010 and 2012 was conducted for patients undergoing surgery for scoliosis. Patients with diagnoses other than AIS were excluded. Patients with incomplete preoperative or intraoperative data were also excluded. Relevant clinical information such as age, sex, number of levels fused, and major Cobb angle were recorded. Preoperative neuromonitoring measurements and intraoperative neuromonitoring results were reviewed by an attending neurologist. Any instance in which an intraoperative surgical plan or neuromonitoring result interpretation was influenced by preoperative results was recorded. Further imaging obtained based on preoperative results was noted. Any acute neurologic complication such as paralysis was noted.

Results Eighty-one patients met inclusion criteria (64 female, 17 male). Average age was 15 years (± 1.92). Major Cobb angle at preoperative evaluation averaged 57.5 degrees (± 10.81 degrees). Ten patients had abnormal preoperative SSEP/TMS results. There were no changes in protocol during intraoperative neuromonitoring based upon preoperative neuromonitoring findings. No additional imaging was required for patients with abnormal preoperative neuromonitoring results. There was no statistically significant difference in preoperative Cobb angle between the group of patients with abnormal preoperative neuromonitoring and those with normal baseline testing.

Conclusion Preoperative SSEP/TMS measurement prior to corrective surgery for AIS has limited utility. There were no instances in which a patient's clinical course was improved by testing. We recommend against routine use of preoperative SSEP/TMS testing for AIS patients requiring corrective surgery.