Prolonged Symptom Duration is Associated With Inferior Quality of Life Outcomes After Surgery for Degenerative Cervical Myelopathy: A Multicenter Cohort Study From the Canadian Spine Outcomes and Research Network

Prospective cohort study. The aims of this study were primarily to evaluate the association between patient-reported symptom duration and postoperative outcomes in patients with degenerative cervical myelopathy (DCM). Secondly, to identify factors associated with the extended duration of symptoms before surgical consultation for DCM. Surgery is the gold standard treatment for progressive or at least moderate DCM; however, the impact of extended symptom duration on patient outcomes remains unknown. This study analyzed patients enrolled in the Canadian Spine Outcomes and Research Network (CSORN) from 2015 to 2023. Patients with mild to severe DCM with 1-year follow-up were included. During initial assessment, surgeons recorded symptom duration as reported by patients categorically with six choices, which were then dichotomized as a binary variable using a 1-year threshold. Differences between groups were analyzed using unadjusted bivariate analysis, and the associations between symptom duration on achievement of minimally clinically important differences (MCID) of PROMs were assessed using multivariable logistic regression analysis. A total of 483 patients (227 with symptoms less than 1 year and 256 with symptoms 1 year or greater) were included. At baseline, BMI (mean=28.2 vs . 29.5, P <0.008), number of comorbidities (2.8 vs . 3.1, P <0.029), and proportion of tobacco users (51% vs . 82%, P <0.027) were significantly higher among those with symptoms 1 year or greater, who also had higher baseline mJOA scores (12.5 vs . 13.2, P <0.002) and worse neck pain (5.63 vs . 4.92, P <0.004). Symptom duration of less than 1 year was associated with higher odds of achieving MCID for the outcomes Neck Disability Index (OR=1.64, 95% CI=1.05-2.55, P <0.030), SF-12 PCS (OR=1.98, 95% CI=1.22-3.19, P <0.005), and EQ-5D (OR=2.08, 1.30-3.33, P <0.002) at 12 months after surgery. The odds of reaching the MCID for the mJOA did not significantly differ by symptom duration (OR=1.41, 95% CI=0.88-2.24, P <0.153). Patients with symptom durations1 year or greater at the time of consulting a spine surgeon experienced inferior postoperative outcomes for disability and health-related quality of life compared with patients with symptom durations of less than 1 year, despite similar neurological outcomes. Smoking was among the factors associated with a prolonged duration of symptoms. These results suggest that efforts to prioritize early diagnosis by primary care physicians and timely referral for surgery are warranted. Level 3.