Symptom Duration as a Predictor of Neurological Recovery After Decompression Surgery for Degenerative Cervical Myelopathy

Background The impact of symptom duration on postoperative recovery in degenerative cervical myelopathy (DCM) remains controversial. While earlier decompression is often recommended, patient outcomes are likely influenced by a combination of factors. This study aimed to evaluate whether the duration of symptoms significantly affects neurological recovery. Methods We performed a retrospective analysis of 142 consecutive patients (mean age 66.2 years, 63% male) who underwent anterior or posterior cervical decompression. Baseline variables included age, sex, body mass index (BMI), American Society of Anesthesiologists (ASA) status, number of stenotic segments, surgical approach, preoperative Japanese Orthopaedic Association (JOA) score, and duration of symptoms. Neurological function was assessed by JOA score preoperatively and at three and 12 months postoperatively. Multivariate linear regression identified independent predictors of continuous JOA change, while multivariate logistic regression assessed factors associated with achieving a clinically meaningful gain (≥1.5 points in JOA score). Results Overall, JOA scores improved by 1.16 ± 2.1 points (8.9%; p < 0.001) at three months and by 1.60 ± 2.2 points (12.2%; p < 0.001) at 12 months. Patients with severe myelopathy (JOA < 12) demonstrated the greatest gains (+1.99 at three months; +4.58 at 12 months; both p < 0.01), whereas those with mild symptoms showed minimal change. In multivariate analysis, a lower baseline JOA score was the sole predictor of greater continuous improvement at three months (p < 0.001) and remained significant at 12 months alongside ASA class (p = 0.017) and BMI (p = 0.027). Symptom duration did not predict the magnitude of continuous change. However, each additional month of preoperative symptoms decreased the odds of achieving a ≥1.5-point gain at three months by 0.7% (p = 0.045). By 12 months, only patient sex (male vs. female; OR: 0.81; p = 0.046) independently predicted clinically meaningful recovery. Conclusion Baseline neurological impairment is the strongest determinant of postoperative improvement in DCM, with systemic health also influencing long-term gains. Although longer symptom duration modestly reduces the likelihood of early clinically meaningful recovery, substantial improvement remains achievable after delay. These findings reinforce the importance of early diagnosis and timely surgical referral.