title: SSEP analysis in surgery of idiopathic scoliosis: the influence of spine deformity and surgical approach.
abstract: The study was conducted to assess the possible impact of spine deformity in patients with idiopathic scoliosis (IS) on tibial nerve somatosensory evoked potentials (t-SSEPs) and the influence of spine correction upon postoperative SSEP recordings. In 61 consecutive patients undergoing 64 spinal instrumentations, 129 pre- and postoperative SSEPs were analyzed. The degree of spine deformity was assessed by the pre-operative Cobb angle of the major scoliotic curve. In a control group, reference values of t-SSEP latencies were established with respect to body height. In a cohort study, IS patients were compared with healthy controls with respect to t-SSEP latency, amplitude, configuration and interside difference. The results of the analysis showed that preoperative-body-height-corrected t-SSEP latencies were prolonged in 61% of patients, with a pathological interside difference in 23.4% of them. The impairment of t-SSEPs was not related to the extent of spine deformity as assessed by the Cobb angle. Even without occurrence of postoperative neurological deficits, postoperative t-SSEPs showed significantly increased latencies without changes in t-SSEP configuration. The prolongation of t-SSEP latencies was related to the surgical procedure (combined ventro-dorsal approach), but not to the extent of spine correction, level of instrumentation, or number of fused segments. The analysis of preoperative t-SSEPs was of no predictive value for intra- or postoperative neurological complications. t-SSEPs are significantly affected in IS patients, although these patients show no obvious clinical neurological deficits. The extent of t-SSEP impairment is not related to the severity of scoliosis. Even in clinically uneventful surgery, the postoperative t-SSEPs can be deteriorated depending on the surgical approach. This indicates a subclinical impact of spine surgery upon spinal cord function.
authors.affiliation: ParaCare, Swiss Paraplegic Center, Institute for Rehabilitation and Research, University Hospital Balgrist, Forchstrasse 340, 8008 Zurich, Switzerland.
authors.forename: Oliver
authors.initials: O
authors.lastname: Hausmann
authors.forename: Kan
authors.initials: K
authors.lastname: Min
authors.forename: Thomas
authors.initials: T
authors.lastname: Böni
authors.forename: Thomas
authors.initials: T
authors.lastname: Erni
authors.forename: Volker
authors.initials: V
authors.lastname: Dietz
authors.forename: Armin
authors.initials: A
authors.lastname: Curt
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers; D001827:Body Height / Q000502:physiology; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D012600:Scoliosis / Q000503:physiopathology* / Q000601:surgery*; D013116:Spinal Cord / Q000502:physiology; D013131:Spine / Q000002:abnormalities* / Q000601:surgery
chemical_list: D015415:Biomarkers