Preoperative headache severity and the risk of unsuccessful outcomes after anterior surgery for degenerative cervical radiculopathy: a population-based study from the Norwegian Registry for Spine Surgery.

Introduction: Degenerative cervical radiculopathy (DCR) is the most frequent indication for cervical spine surgery. Many patients presenting with arm pain and neck pain, also complain of headache (HA). Research question: This study investigates whether preoperative HA is an independent predictor of a non-successful surgical outcome. Materials and methods: A cohort of 6234 patients undergoing anterior cervical surgery for DCR were operated, prospectively registered in the Norwegian Registry for Spine Surgery (NORspine) and followed for one year. Baseline headache severity measured by numeric rating scale (NRS-HA) was used as exposure in multivariable mixed logistic regression models to determine its association with surgical non-success, defined as <35% improvement in the Neck Disability Index (NDI) at 12 months, while adjusting for possible confounders. Results: A total of 4689 (75%) reported DCR-concomitant headaches at baseline, and the loss to follow-up at 12 month was 30%. Each 1-unit increase on the NRS-HA scale was significantly associated with a higher likelihood of surgical non-success, as shown by both the multivariable regression model (8% increase per unit, odds ratio (OR: 1.08, 95% confidence interval (CI): 1.05-1.11, p < 0.001) and the mixed logistic model (21% increase per unit, OR: 1.21, 95% CI: 1.14-1.27, p < 0.001). Discussion and conclusion: Higher preoperative headache severity was an independent prognostic factor for non-successful outcomes following DCR surgery. This information can be used in preoperative counselling, aimed at improving patient selection and prognosis.