Is Preoperative Duration of Symptoms a Significant Predictor of Functional Outcomes in Patients Undergoing Surgery for the Treatment of Degenerative Cervical Myelopathy?

Abstract

Preoperative duration of symptoms may significantly impact outcomes in patients treated surgically for degenerative cervical myelopathy (DCM). To (i) analyze whether duration of symptoms is associated with preoperative functional impairment, disability, and quality of life and (ii) determine the optimal timing for decompressive surgery. Patients with DCM were prospectively enrolled in either the AOSpine North American or International study at 26 global sites (n=757). Postoperative functional impairment was evaluated at 1-yr using the modified Japanese Orthopaedic Association (mJOA) score. Change scores between baseline and 1-yr were computed for the mJOA. Duration of symptoms was dichotomized into a "short" and "long" group at several cut-offs. Analysis of covariance was used to evaluate differences in change scores on the mJOA between duration of symptoms groups in 4-mo increments. Our cohort consisted of 424 men and 255 women, with a mean duration of symptoms of 26.1±36.4 mo (0.25-252 mo). Duration of symptoms was not correlated with preoperative mJOA, Nurick, Neck Disability Index, or Short-Form (SF)-36 Physical and Mental Component Scores. Patients with a duration of symptoms shorter than 4 mo had significantly better functional outcomes on the mJOA than patients with a longer duration of symptoms (>4 mo). Thirty-two months was also a significant cut-off. Patients who are operated on within 4 mo of symptom presentation have better mJOA outcomes than those treated after 4 mo. It is recommended that patients with DCM are diagnosed in a timely fashion and managed appropriately.