Outcome of Patients With Mild Degenerative Cervical Myelopathy Treated Nonoperatively: An Observational Study From the Canadian Spine Outcome and Research Network.

Abstract

Degenerative cervical myelopathy (DCM) is the most common cause of spinal cord dysfunction in adults. The natural history of mild DCM is not fully understood, and both operative and nonoperative strategies have been proposed as treatment modalities. The aim of this study was to analyze the outcome of patients with mild DCM treated nonoperatively and identify risk factors for neurological deterioration and conversion to surgery. All patients with mild DCM (modified Japanese Orthopaedic Association [mJOA] score 15-17), enrolled between 2015 and 2023, who were initially treated nonoperatively, as part of an ongoing prospective, multicenter observational cohort study were included. Neurological function (mJOA), patient-reported outcomes (neck disability index, EuroQol-5D, short form-12, numeric rating scale [NRS]), and radiographic findings at enrollment and 1 year were assessed. Progression of disease was defined as neurological deterioration by ≥2 mJOA. Conversion to surgery was a secondary end point. One hundred forty patients with mild DCM were initially treated nonoperatively. The mean mJOA score was 16.8 ± 0.8, with no clinically significant change after 1 year (16.5 ± 1.3; P = .031). Improved EuroQol-5D, relief in the NRS arm, and neck pain below the minimal clinically important difference level were noted after 1 year. A drop of ≥2 mJOA points occurred in 13.3% (n = 14). Seventeen patients (12.1%) crossed over to surgical treatment at an average time of 3.4 years. Patients who crossed over had lower baseline mJOA scores (16.2 ± 1.0 vs 16.7 ± 0.9; P = .03), but otherwise comparable patient-reported outcomes at baseline (P > .05). Delayed surgery improved NRS neck pain (5.0 ± 3.1 vs 1.9 ± 1.4; P = .02). Neurological deterioration or the need for surgery is relatively uncommon in patients with conservatively treated mild DCM. A deterioration rate of 13.3% at 1 year and a conversion rate of 12.1% over 3.4 years with no clear risk factors were noted. Crossover patients presented with worse mJOA. No other clinically significant parameter was found to be a risk factor for neurological deterioration nor a driver for crossover.