The SIMS: Severity on Imaging Myelopathy Score. A new multi-parametric MRI-based scoring system for degenerative cervical myelopathy

Abstract Cervical spondylotic myelopathy (CDM) is the leading cause of functional disability of spinal origin in people over 50 years old. The objective of the present study was to establish a multiparametric weighted scoring system, easy to use in daily practice, based on the most significant MRI signs and correlated as strongly as possible with the clinical presentation (mJOA) – the SIMS for Severity on Imaging Myelopathy Score. 99 patients who underwent clinical and radiological evaluation by mJOA and MRI between January 2015 and March 2021 were retrospectively included. The variables included in the score were the Fujiwara ratio, the T2-weighted intramedullary hyperintensity, the aspect of the perimedullary fluidcisterns, the Torg-Pavlov ratio, the local kyphosis and the number of stenotic levels. Each variable was first correlated to the mJOA score for each patient, making possible at the end to construct the final SIMS, and validate it by comparison with mJOA scores. The variables significantly correlated were the T2-weighted intramedullary hyperintensity, the reduction of perimedullary fluid spaces and the number of stenotic levels (p < 0.05). Then points were assigned to each variable according to their relative importance and made it possible to construct the definitive SIMS. The final correlation coefficient between SIMS and mJOA score was -0.747. This work showed that this new multi-parametric MRI-based scoring system represents a consistent mean to characterize the degree of severity of the degenerative cervical myelopathy.