New-onset headache and early aggravation of pre-existing headache after anterior cervical discectomy and fusion: a retrospective cohort study

Abstract

Pre-existing cervicogenic headache often improves after anterior cervical discectomy and fusion (ACDF); however, new-onset postoperative headache and early aggravation of pre-existing headache remain poorly characterized. This study evaluated these outcomes separately and assessed their clinical phenotypes and associated factors. This single-center retrospective cohort study included 1,993 consecutive patients who underwent ACDF between January 2017 and December 2024 for cervical radiculopathy ( n = 866), degenerative cervical myelopathy ( n = 806), isolated soft-disc herniation ( n = 314), ossification of the posterior longitudinal ligament ( n = 5), or revision surgery ( n = 2). New-onset headache was assessed through postoperative day 30 in 1,443 patients without active preoperative headache. Early aggravation was assessed at the first postoperative evaluation (24–72 h) in 550 patients with active headache and was defined as an increase of ≥ 2 points in headache visual analog scale (VAS) score. Multivariable logistic regression was performed in each complete risk set. Separate 1:2 Mahalanobis-matched and Firth-penalized models were used as sensitivity analyses. New-onset headache occurred in 112 of 1,443 patients (7.8%) within 30 days, whereas early aggravation occurred in 83 of 550 patients (15.1%) at 24–72 h. Among the 195 patients meeting either outcome definition, the phenotype was cervicogenic in 133, low-CSF-pressure in 34, tension-type-like in 21, and pulsatile/migraine-like in 7. Intraoperative cerebrospinal fluid (CSF) leakage was associated with both new-onset headache (adjusted odds ratio [aOR] 26.36, 95% confidence interval [CI] 11.76–59.08) and early aggravation (aOR 33.50, 95% CI 9.20–122.05). Fusion of ≥ 3 segments was also associated with both outcomes. The principal associations remained consistent in the matched and Firth-penalized analyses. Optimism-corrected areas under the receiver operating characteristic curve were 0.680 and 0.697. New-onset headache within 30 days occurred in 7.8% of patients without active preoperative headache, whereas clinically meaningful early aggravation at 24–72 h occurred in 15.1% of patients with active headache. CSF leakage and fusion of ≥ 3 segments were the most consistent associated factors. These findings may inform perioperative counselling and early postoperative assessment, but external validation is required before individual risk prediction is considered.