The association between cervical artery dissection and spinal manipulation among US adults

Purpose Cervical artery dissection (CeAD), which includes both vertebral artery dissection (VAD) and carotid artery dissection (CAD), is the most serious safety concern associated with cervical spinal manipulation (CSM). We evaluated the association between CSM and CeAD among US adults. Methods Through analysis of health claims data, we employed a case–control study with matched controls, a case–control design in which controls were diagnosed with ischemic stroke, and a case-crossover design in which recent exposures were compared to exposures in the same case that occurred 6–7 months earlier. We evaluated the association between CeAD and the 3-level exposure, CSM versus office visit for medical evaluation and management (E&M) versus neither, with E&M set as the referent group. Results We identified 2337 VAD cases and 2916 CAD cases. Compared to population controls, VAD cases were 0.17 (95% CI 0.09 to 0.32) times as likely to have received CSM in the previous week as compared to E&M. In other words, E&M was about 5 times more likely than CSM in the previous week in cases, relative to controls. CSM was 2.53 (95% CI 1.71 to 3.68) times as likely as E&M in the previous week among individuals with VAD than among individuals experiencing a stroke without CeAD. In the case-crossover study, CSM was 0.38 (95% CI 0.15 to 0.91) times as likely as E&M in the week before a VAD, relative to 6 months earlier. In other words, E&M was approximately 3 times more likely than CSM in the previous week in cases, relative to controls. Results for the 14-day and 30-day timeframes were similar to those at one week. Conclusion Among privately insured US adults, the overall risk of CeAD is very low. Prior receipt of CSM was more likely than E&M among VAD patients as compared to stroke patients. However, for CAD patients as compared to stroke patients, as well as for both VAD and CAD patients in comparison with population controls and in case-crossover analysis, prior receipt of E&M was more likely than CSM.