Study Design. Prospective national survey.
Objective. To estimate the risk of serious and relatively minor adverse events following chiropractic manipulation of the cervical spine by a sample of U.K. chiropractors.
Summary of Background Data. The risk of a serious adverse event following chiropractic manipulation of the cervical spine is largely unknown. Estimates range from 1 in 200,000 to 1 in several million cervical spine manipulations.
Methods. We studied treatment outcomes obtained from 19,722 patients. Manipulation was defined as the application of a high-velocity/low-amplitude or mechanically assisted thrust to the cervical spine. Serious adverse events, defined as “referred to hospital A&E and/or severe onset/worsening of symptoms immediately after treatment and/or resulted in persistent or significant disability/incapacity,” and minor adverse events reported by patients as a worsening of presenting symptoms or onset of new symptoms, were recorded immediately, and up to 7 days, after treatment.
Results. Data were obtained from 28,807 treatment consultations and 50,276 cervical spine manipulations. There were no reports of serious adverse events. This translates to an estimated risk of a serious adverse event of, at worse ≈1 per 10,000 treatment consultations immediately after cervical spine manipulation, ≈2 per 10,000 treatment consultations up to 7 days after treatment and ≈6 per 100,000 cervical spine manipulations. Minor side effects with a possible neurologic involvement were more common. The highest risk immediately after treatment was fainting/dizziness/light-headedness in, at worse ≈16 per 1000 treatment consultations. Up to 7 days after treatment, these risks were headache in, at worse ≈4 per 100, numbness/tingling in upper limbs in, at worse ≈15 per 1000 and fainting/dizziness/light-headedness in, at worse ≈13 per 1000 treatment consultations.
Conclusion. Although minor side effects following cervical spine manipulation were relatively common, the risk of a serious adverse event, immediately or up to 7 days after treatment, was low to very low.
We evaluated the risk of serious and minor adverse events following chiropractic manipulation of the cervical spine in 19,722 patients. The estimated risk of a serious adverse event was, at worse ≈1 per 10,000 treatment consultations immediately after cervical spine manipulation, ≈2 per 10,000 treatment consultations up to 7 days after treatment, and ≈6 per 100,000 cervical spine manipulations. Risks of minor adverse events were more common.
From the *Department of Research and Professional Development, Anglo-European College of Chiropractic, Bournemouth, United Kingdom; and †Department of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, United Kingdom.
Acknowledgment date: November 29, 2006. First revision date: January 30, 2007. Second revision date: March 22, 2007. Acceptance date: March 23, 2007.
Supported by the British Chiropractic Association and Howden Medical Insurance Services, and the Anglo-European College of Chiropractic. No conditions were placed on these contributions in terms of the study's design, conduct, and publication.
The manuscript submitted does not contain information about medical device(s)/drug(s).
Institutional, professional organizational, and other funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript.
Address correspondence and reprint requests to Haymo W. Thiel, DC, PhD, Department of Research and Professional Development, Anglo-European College of Chiropractic, 13-15 Parkwood Road, Bournemouth BH5- 2DF, UK; E-mail: firstname.lastname@example.org