In this study, researchers from the Anglo-European College of Chiropractic in Bournemouth, UK followed the response by 19,722 patients after cervical (neck) manipulation.

First, the details.

• Data were obtained from 28,807 treatment consultations and 50,276 cervical spine manipulations.
• Manipulation was defined as the application of a high-velocity/low-amplitude or mechanically assisted thrust to the cervical spine.
• Serious adverse events included hospital referral and/or severe onset or worsening of symptoms immediately after treatment and/or resulted in persistent or significant disability or incapacity.
• Minor adverse events included a worsening of presenting symptoms or onset of new symptoms recorded up to 7 days after treatment.

And, the results.
There were no reports of serious side effects, which statistically translated to the following estimated risk of a serious side effect.

• 1 per 10,000 treatment consultations immediately after cervical spine manipulation
• 2 per 10,000 treatment consultations up to 7 days after treatment
• 6 per 100,000 cervical spine manipulations, total

Minor side effects with a possible neurologic involvement were more common.

• Immediately after treatment: fainting/dizziness/light-headedness in 16 per 1000 treatment consultations
• Up to 7 days after treatment: headache in 4 per 100, numbness/tingling in upper limbs in 15 per 1000 and fainting/dizziness/light-headedness in 13 per 1000 treatment consultations

The bottom line?
The authors concluded, “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.”

OK, but I’m not clear on how one estimates a risk statistically, when none are reported.

12/9/07 18:19 JR