Chiropractic Spinal Manipulative Therapy for Migraine
By Dr. Alexsander Chaibi
Migraine is a common health problem with substantial health and socioeconomic costs. On the recent Global Burden of Disease study, migraine was ranked as the third most common condition.1
About 15% of the general population have migraine.2 ,3 Migraine is usually unilateral with pulsating and moderate/severe headache which is aggravated by routine physical activity, and is accompanied by photophobia and phonophobia, nausea and sometimes vomiting.4 Migraine exists in two major forms, migraine without aura and migraine with aura (box 1). Aura is reversible neurological disturbances of the vision, sensory and/or speech function, occurring prior to the headache. However, intraindividual variations from attack to attack are common.5 ,6 The origin of migraine is debated. The painful impulses may originate from the trigeminal nerve, central and/or peripheral mechanisms.7 ,8 Extracranial pain sensitive structures include the skin, muscles, arteries, periosteum and joints. The skin is sensitive to all usual forms of pain stimuli, while temporal and neck muscles may especially be sources for pain and tenderness in migraine.9–11 Similarly, the frontal supraorbital, superficial temporal, posterior and occipital arteries are sensitive to pain.9 ,12
Pharmacological management is the first treatment option for migraineurs. However, some patients do not tolerate acute and/or prophylactic medicine due to side effects or contraindications due to comorbidity of other diseases or due to a wish to avoid medication for other reasons. The risk of medication overuse due to frequent migraine attacks represents a major health hazard with direct and indirect cost concerns. The prevalence of medication overuse headache (MOH) is 1–2% in the general population,13–15 that is, about half the population suffering chronic headache (15 headache days or more per month) have MOH.16 Migraine causes loss of 270 workdays per year per 1000 persons from the general population.17 This corresponds to about 3700 work years lost per year in Norway due to migraine. The economic cost per migraineur was estimated to be $655 in USA and €579 in Europe per year.18 ,19 Owing to the high prevalence of migraine, the total cost per year was estimated to be $14.4 billion in the USA and €27 billion in the EU countries, Iceland, Norway and Switzerland at that time. Migraine costs more than neurological disorders such as dementia, multiple sclerosis, Parkinson’s disease and stroke.20 Thus, non-pharmacological treatment options are warranted.
The Diversified technique and the Gonstead method are the two most commonly used chiropractic manipulative treatment modalities in the profession, used by 91% and 59%, respectively,21 ,22 along with other manual and non-manual interventions, that is, soft tissue techniques, spinal and peripheral mobilisation, rehabilitation, postural corrections and exercises as well as general nutrition and dietetic advice.
A few spinal manipulative therapy (SMT) randomised controlled trials (RCTs) using the Diversified technique have been conducted for migraine, suggesting an effect on migraine frequency, migraine duration, migraine intensity and medicine consumption.23–26 However, common for previous RCTs are the methodological shortcomings such as inaccurate headache diagnosis, that is, questionnaire diagnoses used are imprecise,27 inadequate or no randomisation procedure, lack of placebo group, and primary and secondary end points not prespecified.28–31 In addition, previous RCTs did not consequently adhere to the recommended clinical guidelines from the International Headache Society (IHS).32 ,33 At present, no RCTs have applied the Gonstead chiropractic SMT (CSMT) method. Thus, considering the methodological shortcomings in previous RCTs, a clinical placebo-controlled RCT with improved methodological quality remains to be conducted for migraine.
The SMT mechanism of action on migraine is unknown. It is argued that migraine might originate from a complexity of nociceptive afferent responses involving the upper cervical spine (C1, C2 and C3), leading to a hypersensitivity state of the trigeminal pathway conveying sensory information for the face and much of the head.34 ,35 Research has thus suggested that SMT may stimulate neural inhibitory systems at different spinal cord levels, and might activate various central descending inhibitory pathways.36–40 However, although the proposed physiological mechanisms are not fully understood, there are most likely additional unexplored mechanisms which could explain the effect SMT has on mechanical pain sensitisation.