Assessing Neurologic Complications in Thoracic Three-Column Osteotomy

Abstract

Study Design: Retrospective comparative study. Objective: To investigate the occurrence of neurologic complications in patients undergoing thoracic three-column osteotomy (3CO) utilizing an MRI-based classification that assesses spinal cord shape and the presence of cerebrospinal fluid (CSF) at the curve apex, and evaluate its prognostic capacity for postoperative neurologic deficits. Summary of Background Data: Recent advancements in correction techniques have improved outcomes for severe spinal deformity patients undergoing 3CO. A novel MRI-based spinal cord classification system was introduced, but its validation and association with postoperative complications remain unexplored. Materials and Methods: Between September 2012 and September 2018, a retrospective analysis was conducted on 158 adult patients with spinal deformities undergoing 3CO. Radiographic parameters were measured. T2-weighted axial MRI was employed to describe spinal cord morphology at the apex. Intraoperative neurophysiologic monitoring (INOM) alerts were recorded, and preoperative and postoperative neurologic functions were assessed using the Frankel score. Categorical data were compared using the Chi-Square or Fisher’s exact test. The paired t-test was utilized to assess the mean difference between pre- and postoperative measurements, while the one-way ANOVA and independent t-test were employed for comparative analyses among the different spinal cord types. Results: Patients were categorized into three groups: type 1, type 2, and type 3, consisting of 12, 85, and 61 patients. Patients with type 3 morphology exhibited larger Cobb angles of the main curve (P<.001). This disparity persisted both postoperatively and during follow-up (P<.05). IONM alerts were triggered in 32 patients (20.3%), with a distribution of one case in type 1, six cases in type 2, and 22 cases in type 3 morphologies (P<.001). New neurologic deficits were observed in 15 patients (9.5%), with one, three, and 11 cases in type 1, 2, and 3 morphologies, respectively. Conclusions: Patients with type 3 morphology exhibited greater spinal deformity severity, higher likelihood of preoperative neurologic deficits, and an elevated risk of postoperative neurologic complications. This underscores the utility of the classification as a tool for predicting postoperative neurologic complications in patients undergoing thoracic 3CO. Level of Evidence: Level IV.