A Novel Scoring System for Ossification of Posterior Longitudinal Ligament of the Cervical Spine Based on Magnetic Resonance Imaging—CSFM Scoring System

OBJECTIVE: To establish a new scoring system to assess spinal cord compression of ossification of posterior longitudinal ligament (OPLL) of the cervical spine.METHODS: Literature review and expert advice were used to determine variables of the novel CSFM scoring system. The CSFM score included 4 variables: curvature of spinal cord (C), increased signal intensity of spinal cord (S), cerebrospinal fluid imaging (F), and cross-section morphology of spinal cord (M). From June 2015 to June 2018, clinical and imaging data of 387 patients with cervical OPLL were retrospectively analyzed. The 4 variables were measured and recorded. Different scores were assigned based on analysis of the relationship between the variables and the Japanese Orthopaedic Association score. Two spine surgeons scored the patients according to the CSFM score and analyzed the internal consistency and reliability of the CSFM score.RESULTS: The CSFM scoring system consisted of 4 variables, each of which was divided into 4 grades. Each variable was assigned a score of 0-3 according to different grades. The total possible score was 12, and the minimum score was 0. A higher score indicated more severe spinal cord compression.CONCLUSIONS: The CSFM scoring system can effectively reflect the degree of spinal cord compression for cervical OPLL.