A study on neck generated headaches, snappily called:
Dose response and efficacy of spinal manipulation for chronic cervicogenic headache: a pilot randomized controlled trial
by Haas and co-workers was published in the uber serious Spine (The Spine Journal 2010; 10:117-128) which said that chiropractic was good at sorting out these sorts of headaches.
As we all know, headaches are very common (with up to 16% of the population having one at any one time). They are also very disabling (leading to days lost from work, absenteeism costs and increased medical spending by the NHS – who just don’t need this sort of thing). Headaches are broken down into a couple of groups: primary and secondary. The primary group is made up of:
- tension-type headaches
- cervicogenic headache (CGH)
This last lot, the CGH, account for a significant proportion of the 16% estimate of those suffering primary headaches (but Nilson and Sjaastad have estimated the range from 0.4%-4.6%). These headaches are linked to neck pain and mechanical dysfunction. It is theorized, treating neck pain and mechanical dysfunction through manual therapies will help reduce the headache symptoms.
Systematic reviews have been conducted on the usefulness of spinal manipulative therapy (SMT) in the treatment of this CGH. However the treatment plans offered vary from once per week for three weeks to twice per week for 8 weeks. This, clearly, demonstrates a lack of clinical understanding and consensus shown in the research. This then prevents us from being able to confidently set out the prognosis and expectations with respect to SMT.
So, the purpose of the study was to determine the efficacy of spinal manipulation in CGH and compare a high-dose and low-dose SMT application to a light massage.
The study on cervicogenic headaches:
One group received low-dose SMT (8 treatments), another high-dose SMT (16 treatments), another group low-dose light massage (8 treatments) and, finally, another high-dose light massage (16 treatments). The study showed some interesting things:
- While treatment dose had no effect on the use of medication, those receiving SMT used 1/3 less medication at 24 weeks.
- With respect to the number of cervicogenic headaches experienced, those receiving SMT experienced 2.6 fewer headaches per week compared to those receiving light massage.
- At the end of 24 weeks, those receiving SMT experienced 2.1 fewer headaches per week compared to those receiving light massage.
- While dose effects were small, those who received high-dose SMT experienced a greater improvement in neck pain (-5.9 at 12 wks; -10.6 at 24 wks)
- CGH pain, the number of headaches experienced per week and the amount of medication intake all reduced, with sustained reductions, favouring the SMT group.
Lastly, at the eight week point, the number of weekly headaches was reduced 50% in those patients receiving SMT and on secondary analysis, there was a 50% reduction in symptoms (obtained via an outcome measure) was achieved in 80% of those receiving SMT.
The authors point out several key limitations to this study:
- The study design was highly complex and multifactorial.
- There was a small number of patients within each subgroup.
- Multiple headache classifications were present within many patients.
Interestingly, for us as chiros, there was no difference between the two dosages of SMT (though SMT proved to be more effective than light massage, irrespective of dosage). And, as we’d expect, the differences between the SMT and the light massage group were not only statistically significant but clinically significant as well.
This study is highly relevant and helpful to clinical practice as it strengthens the use of cervical spine manipulation in the treatment of CGH. It is also helpful as it demonstrates that patients do not tend to be cured by this intervention alone, indicating that CGH may require a combined intervention approach which includes exercise, soft-tissue therapy, spinal manipulation and education.