433 Trajectory-based Classification of Recovery Potential in Mild Degenerative Cervical Myelopathy: Analysis of a Prospective Multicentre Dataset of 1047 Patients

Abstract

INTRODUCTION: Degenerative Cervical Myelopathy (DCM) is the leading cause of disability secondary to a spinal pathology in adults. There exists clinical equipoise between surgery and conservative management with monitoring for patients with mild DCM. METHODS: A harmonized dataset was developed from the AOSpine North America, AOSpine International datasets as well as the CSM-Protect trial (N:1047). DCM patients (mJOA ≥15) were selected from the harmonized dataset. Latent class trajectory modeling was applied to classify patients into distinct trajectories. The optimal number of trajectories were chosen based on i) least Bayesian Information Criterion; ii) posterior probability >0.70; iii) odds of correct classification >5; and concordance between the estimated and actual proportion of patients assigned to a class. Predictors of recovery trajectories were identified using descriptive statistics and logistic regression on baseline variables. RESULTS: Two distinct recovery trajectories were revealed from our analysis. Good recovery trajectory had patients that improved to near-maximal mJOA scores within 12 months. Functional decline trajectory was characterized by a decline in more than two mJOA points over 12 months. There were 33 patients (15.6%) that followed functional decline and 179 that showed good recovery (84.4%). Demographic factors associated with following a functional decline trajectory included older age, hypertension, and higher baseline Nurick score. Posterior laminectomy and fusion was associated with functional decline compared to anterior fixation. CONCLUSIONS: Mild DCM can be classified into one of two distinct subpopulations with different recovery trajectories. This study lends support to the heterogeneity of mild DCM and classifying the clinical course of mild DCM based on defined clinical phenotypes rather than baseline severity of myelopathy alone. We also discovered that anterior surgery is associated with better neurological recovery in the context of mild DCM patients.