Introduction: This study aims to analyze whether a longer duration of symptoms is associated with poor surgical outcomes and to determine the optimal timing for decompressive surgery in patients with mild, moderate and severe degenerative cervical myelopathy (DCM).
Methods: 350 patients with symptomatic DCM were prospectively enrolled in either the CSM-North America or International study at 12 sites in North America. Postoperative functional status was evaluated at 6-, 12- and 24-months using the modified Japanese Orthopaedic Association (mJOA). Duration of symptoms was dichotomized into a “short” and “long” group at several cut-offs. An iterative mixed model analytic approach procedure was used to evaluate differences in change scores on the mJOA between duration groups in 1-month increments. This analysis was repeated for subgroups of patients with mild (mJOA=15), moderate (mJOA=12-14) and severe (mJOA<12) myelopathy.
Results: The mean duration of symptoms of our cohort was 25.71±36.68 months (range: 1-240 months). In unadjusted analysis, patients with a duration of symptoms shorter than 4 months had significantly better functional outcomes based on the mJOA (p=0.04) than patients with a longer duration of symptoms (>4 months). On average, patients with a shorter duration of symptom improved by 3.76 on the mJOA, whereas those with a duration 4 months or longer only exhibited a 2.87 mean gain (p=0.0276). Twenty-nine months was identified as the next important cut-off beyond which patients had a significantly worse outcome on the mJOA. When stratifying by myelopathy severity, we were unable to identify an appropriate cut-off for patients with mild or severe myelopathy. In patients with moderate disease, however, each 1-month delay in surgery significantly impacts clinical outcomes.
Conclusions: Patients who are operated on within 4 months of symptom presentation have better mJOA outcomes, especially those with moderate disease.
Patient Care: The results from this review will encourage timely management of patients with moderate DCM.
Learning Objectives: To better understand the impact of duration of symptoms on surgical outcomes.