Does Spinal Cord Type Predict Intraoperative Neuro-Monitoring Alerts in Scoliosis Correction Surgery? A Systematic Review and Meta-Analysis of Operative and Radiologic Predictors

Abstract

Study Design Systematic literature review and meta-analysis. Objectives Predicting patient risk of intraoperative neuromonitoring (IONM) alerts preoperatively can aid patient counselling and surgical planning. Sielatycki et al established an axial-MRI-based spinal cord classification system to predict risk of IONM alerts in scoliosis correction surgery. We aim to systematically review the literature on operative and radiologic factors associated with IONM alerts, including a novel spinal cord classification. Methods A systematic review and meta-analysis was performed as per the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) Guidelines. A literature search identifying all observational studies comparing patients with and without IONM alerts was conducted. Suitable studies were included. Patient demographics, radiological measures and operative factors were collected. Results 11 studies were included including 3040 patients. Relative to type 3 cords, type 1 (OR = .03, CI = .01-.08, P < .00001), type 2 (OR = .08, CI = .03, P <.00001) and all non-type 3 cords (OR = .05, CI = .02-.16, P < .00001) were associated with significantly lower odds of IONM alerts. Significant radiographic measures for IONM alerts included coronal Cobb angle (MD = 10.66, CI = 5.77-15.56, P < .00001), sagittal Cobb angle (MD = 9.27, CI = 3.28-14.73, P = .0009), sagittal deformity angle ratio (SDAR) (MD = 2.76, CI = 1.57-3.96, P < .00001) and total deformity angle ratio (TDAR) (MD = 3.44, CI = 2.27-4.462, P < .00001). Clinically, estimated blood loss (MD = 274.13, CI = −240.03-788.28, P = .30), operation duration (MD = 50.79, CI = 20.58-81.00, P = .0010), number of levels fused (MD = .92, CI = .43-1.41, P = .0002) and number of vertebral levels resected (MD = .43, CI = .01-.84, P = .05) were significantly greater in IONM alert patients. Conclusions This study highlights the relationship of operative and radiologic factors with IONM alerts.