Osteopathic Manipulative Treatment in Frequent Episodic Tension-type Headache: the EBOTTH Multicentric Study

Background:

Primary headache disorders are very common throughout the world, producing widespread and substantial disability and representing a concrete public-health priority. Tension-type headache (TTH) is the most common type of primary headache disorder, with a lifetime prevalence in the general population ranging between 30% and 78% in different studies. In general, headache is a chronic disorder with episodic manifestations that may range from few attacks/year up to daily episodes. Its impact on individuals' lives is greater than has generally been realized, including psychiatric, psychological and social correlates. The impact on patients can be very high, including ictal symptom burden, interictal burden, cumulative burden and impact on other people. The individual burden of TTH includes both symptoms occurring during the attacks (pain, eventually accompanied by no more than one of phonophobia or photophobia, according to International Classification of Headache Disorders) and elements of interictal burden, such as anxiety, mood disorders, affective distress and avoidance behavior. While present, symptoms may cause debility and prostration, and reduce functional ability. Even if patients with TTH generally are not unable to work, effectiveness and productivity may be consistently reduced. This secondary disability is quite significant because headache in general is most common in people between their teens and 50-60 years of age, the productive years. The elements of interictal burden, instead, may continuously affect wellbeing and impair quality of life. Moreover, TTH has a substantial impact on the health system, due to both direct and indirect financial cost. The high prevalence of TTH, considering its individual impact and huge financial costs, has important implications for health policy, since it is a source of high but potentially reducible socioeconomic burden. Essentially, TTH management is a public-health priority.

On the clinical side, tension-type headache has been defined as a multifactorial disorder, conceivably implying the need for tailored treatment strategies. Headache-related disability can usually be reduced by identifying and avoiding triggers combined with pharmacologic and non-pharmacologic treatment (such as relaxation and stress management techniques or physical therapies), but effective treatment modalities are still lacking. Particularly, symptomatic drugs are effective for episodes of TTH, whereas preventive treatment (indicated for frequent and chronic TTH) is, on average, barely effective, and do not display good tolerability. Patients are turning to complementary or alternative therapies for headaches, including osteopathic manipulative therapy (OMTh). One previous pilot study carried out by the investigators has suggested an efficacy for OMTh in frequent episodic TTH, that might represent an alternative treatment strategy to prophylactic drugs. Frequent episodic TTH (ETTH) was chosen for this study since it is the most common diagnostic category with indications for prophylactic drug management. To date there is no rigorously tested evidence that manual therapies in general have a positive effect on TTH, as many reviewers have found. Conflicting results in previous studies might be due both to the low number of clinical trials and an indiscriminate application of different techniques. Some studies, however, have demonstrated positive effects of manipulative therapy.

A systematic review found spinal manipulative therapy as effective as commonly used first-line prophylactic medications for both TTH and migraine headaches, but the Authors emphasized that their conclusions were based on only a few trials, raising the question of whether their analysis was methodologically adequate. A more recent systematic review concluded that spinal manipulation might alleviate TTH but that the small quantity of available data prevented any definitive conclusions. The combination of physical therapies with medications, can also increase the success of the treatment, particularly in case of comorbid mood disorders and unremitting headaches, as previously suggested. Although results of these and others published studies suggest positive effects, OMTh has rarely been rigorously tested for the care of patients with headache in general.

OMTh is not free of costs but is plausibly characterized by fewer contraindications and adverse events than conventional pharmacological treatments, and particularly indicated for patients not compliant with drug regimens and those at increased risk of adverse drug effects. Notably, there is disparity between patient perceptions and clinical definitions of adverse events, as a conceptual model with four inter-related components (expectation, personal investment, osteopathic encounter and clinical change) has suggested. Patients might report mild effects following OMTh and in general all forms of manual therapy, but these effects should not be strictly regarded as adverse events. Our previous pilot trial did not observe adverse events among ETTH patients belonging to both arms of the study (treatment and sham). Exceedingly rare serious adverse events may be observed after spine manipulation, only one of many different techniques usually administered in osteopathic clinical field and recommendations have been already published to meet the requirements of the principles of prevention and precaution. For example, minor unwanted effects of prior manipulation should be searched routinely and taken as contraindication for future spinal manipulations. Great care should be taken when particular anatomic conditions such as cord encroachment or increased vertebra-basilar risk are present. Certainly, besides effectiveness, still to be completely proven, the financial impact of OMTh on subjects and health systems could be also a topic of appraisal for future comparative studies.