Association between spinal manipulative therapy and cervical artery dissection in patients with neck pain or headache: a retrospective cohort study

OBJECTIVES: Cervical artery dissection (CeAD) has been proposed as a sequela of spinal manipulative therapy (SMT), however, protopathic bias arising from care-seeking for CeAD symptoms (e.g., neck pain/headache) may overestimate observed associations. Among adults experiencing new neck pain/headache, we tested the null hypothesis of no significant CeAD risk within 30 days following SMT compared to matched ibuprofen-prescribed controls. METHODS: We searched United States TriNetX Linked health records/claims data (2010-2025) for adults seeking care for new episodes of neck pain/headache receiving (1) chiropractor-administered cervical SMT or (2) outpatient visit with ibuprofen prescription, excluding those with previous cerebrovascular disease and/or CeAD, using propensity matching to minimize confounding. We examined the risk ratio (RR) of CeAD (primary outcome), exploring cumulative incidence, CeAD subtypes, absolute risk difference (RD), and negative control outcomes. RESULTS: After matching, there were 431,492 patients per cohort. In the SMT cohort, compared with the ibuprofen cohort, CeAD risk was lower while RD was minimal [95% CI] (RR = 0.53 [0.35, 0.83]; RD=-6.3 [-10.8, -2.0] events per 100,000 patients; P = 0.004). Carotid artery dissection risk was lower; vertebral artery dissection risk was not significantly different. Data quality supported balanced confounders and minimal follow-up loss (< 3%). Negative control outcomes were partially balanced. CONCLUSIONS: This study found no evidence of an increased risk of CeAD after chiropractor-administered cervical SMT compared with ibuprofen prescription in adults seeking care for new episodes of neck pain or headache. Despite the rarity of these events, all clinicians, including chiropractors, should maintain vigilance for CeAD symptoms. Additional multidisciplinary research is warranted to further address potential confounding and examine patient subgroups (e.g., migraine) and stroke.