THE IMPACT OF SURGERY ON PAIN IN DEGENERATIVE CERVICAL MYELOPATHY: A POOLED ANALYSIS OF 1,047 PATIENTS FROM CSM-NA, CSM-I, AND CSM-PROTECT TRIALS

Pain is a significant contributor to quality of life in degenerative cervical myelopathy (DCM). However, its trajectory and factors associated with prolonged chronic pain and resolution is poorly understood. Our study aimed to investigate the impact of surgery on pain in DCM over 12 months. DCM patients with severe pain were queried using a harmonized dataset of the AOSpine CSM-North America, CSM-International, and CSM-Protect clinical trials. Severe acute pain was characterized as a Neck Disability Index pain intensity (NDI-PI) score of 3 or greater. Latent class trajectory modelling (LCTM) was applied to classify patients into distinct trajectories based on their NDI-PI score over the initial 12 months postinjury. Predictors of recovery trajectories were identified using descriptive statistics and multinomial logistic regression with relative risk ratios (RRR) on demographic and surgical variables. From a total of 1,047 patients, three distinct recovery trajectories were discovered from our analysis of 305 patients with severe baseline pain (29.1%). Their parabolic course was classified as: 1) complete resolution of pain (n=134, 43.9%), 2) Recovery to moderate pain (n=105, 34.4%), and 3) marginal recovery (n=72, 23.6%). In patients with severe baseline pain, older age, being married, and higher baseline Nurick and mJOA scores were associated with complete resolution. Anxiety and depression were inversely associated with complete resolution. Surgically, complete pain resolution was associated with anterior autograft with autograft, cage, and allograft. Posterior autograft was inversely associated with complete resolution. Severe acute pain can be classified into one of three distinct subpopulations with fundamentally differing clinical courses. There is greater than 50% of unresolved chronic in DCM patients presenting with severe acute pain over the course of 12 months. Given the high prevalence of chronic pain and impact to quality of life, factors associated with pain trajectories may be avenues for futures comparative studies.