415 What Predicts Attainment of Substantial Clinical Benefit in Neck Pain-Related Disability 24 Months After Surgery for Cervical Spondylotic Myelopathy?

INTRODUCTION: Surgery for cervical spondylotic myelopathy (CSM) intends to halt neurological deterioration, but some patients experience significant improvements in disability. Through analysis of Neck Disability Index (NDI) scores for patients undergoing CSM surgery, this study investigates factors that predict attainment of substantial clinical benefit (SCB) for disability. METHODS: Data was obtained from the Quality Outcomes Database CSM dataset, a prospective cohort of 1141 patients from 14 sites. Exclusion criteria included missing baseline or 24-month NDI scores, baseline NDI<20, or no baseline neck pain. Remaining patients were partitioned into training (n=591) and test sets (n=131). Logistic regression and random forest models, with and without principal component analysis (PCA), were trained to predict whether patients achieved SCB at 24 months. RESULTS: Overall, 722 patients met inclusion criteria: mean age 59.8±11.4, 52.8% female, mean BMI 30.6±6.4, mean baseline NDI 45.7±16.2, mean baseline VAS neck pain 6.2±2.8, and mean baseline mJOA 11.8±2.8. Logistic regression without PCA had AUROC of 0.678±0.035 (with PCA:AUROC=0.686±0.031). Random forest without PCA had AUROC of 0.670±0.033 (with PCA:AUROC=0.683±0.031). Significant positive predictors of SCB attainment: baseline neck pain intensity (OR: 1.76, 95% CI:1.68-1.84, p=0.002), neck pain interfering with recreation (OR: 1.51, 95% CI:1.45-1.56, p=0.002), neck pain interfering with work (OR: 1.36, 95% CI:1.31-1.41, p=0.032), neck pain interfering with lifting (OR: 1.36, 95% CI:1.31-1.40, p=0.022). Significant negative predictors: current unemployment (OR: 0.53, 95% CI:0.49-0.58, p=0.034), undergoing fusion including C7 (OR: 0.26, 95% CI:0.22-0.30, p=0.045). CONCLUSIONS: In a large prospective cohort of operative CSM patients, higher baseline neck pain and neck-pain interference with recreation, work, and lifting activities were baseline factors associated with substantial improvements in NDI. Patients who were unemployed or underwent a C7 fusion were at risk of not attaining SCB. This study helps uncover features associated with substantial clinical improvement in disability following CSM surgery.