Spinal manipulative therapy (SMT) is frequently used to manage cervicogenic headache (CGHA). No meta-analysis has investigated the effectiveness of SMT exclusively for CGHA.
The aim of this review was to evaluate the effectiveness of SMT for cervicogenic headache (CGHA). Seven RCTs were eligible. At short-term follow-up, there was a significant, small effect favouring SMT for pain intensity and small effects for pain frequency. There was no effect for pain duration. There was a significant, small effect favouring SMT for disability. At intermediate follow-up, there was no significant effects for pain intensity and a significant, small effect favouring SMT for pain frequency. At long-term follow-up, there was no significant effects for pain intensity and for pain frequency.
The authors concluded that for CGHA, SMT provides small, superior short-term benefits for pain intensity, frequency and disability but not pain duration, however, high-quality evidence in this field is lacking. The long-term impact is not significant.
This meta-analysis can be criticised for a long list of reasons, the most serious of which, in my view, is that it is bar of even the tiniest critical input. The authors state that there has been no previous meta-analysis on this topic. This might be true, but there has been a systematic review of it (published in the leading journal on the subject) which the authors fail to mention/cite (I wonder why!). It is from 2011 and happens to be one of mine. Here is its abstract:
The objective of this systematic review was to assess the effectiveness of spinal manipulations as a treatment option for cervicogenic headaches. Seven databases were searched from their inception to February 2011. All randomized trials which investigated spinal manipulations performed by any type of healthcare professional for treating cervicogenic headaches in human subjects were considered. The selection of studies, data extraction, and validation were performed independently by 2 reviewers. Nine randomized clinical trials (RCTs) met the inclusion criteria. Their methodological quality was mostly poor. Six RCTs suggested that spinal manipulation is more effective than physical therapy, gentle massage, drug therapy, or no intervention. Three RCTs showed no differences in pain, duration, and frequency of headaches compared to placebo, manipulation, physical therapy, massage, or wait list controls. Adequate control for placebo effect was achieved in 1 RCT only, and this trial showed no benefit of spinal manipulations beyond a placebo effect. The majority of RCTs failed to provide details of adverse effects. There are few rigorous RCTs testing the effectiveness of spinal manipulations for treating cervicogenic headaches. The results are mixed and the only trial accounting for placebo effects fails to be positive. Therefore, the therapeutic value of this approach remains uncertain.
The key points here are:
- methodological quality of the primary studies was mostly poor;
- adequate control for placebo effect was achieved in 1 RCT only;
- this trial showed no benefit of SMT beyond a placebo effect;
- the majority of RCTs failed to provide details of adverse effects;
- this means they violate research ethics and should be discarded as not trustworthy;
- the therapeutic value of SMT remains uncertain.
The new paper was published by chiropractors. Its positive result is not clinically relevant, almost certainly due to residual bias and confounding in the primary studies, and thus most likely false-positive. The conclusions seem to disclose more the bias of the review authors than the truth. Considering the risks of SMT of the upper spine (a subject not even mentioned by the authors), I cannot see that the risk/benefit balance of this treatment is positive. It follows, I think, that other, less risky and more effective treatments are to be preferred for CGHA.