Efficacy of spinal manipulation for chronic headache: A systematic review

Background: Chronic headache is a prevalent condition with substantial soci oeconomic impact. Complementary or alternative therapies are increasingly b eing used by patients to treat headache pain, and spinal manipulative thera py (SMT) is among the most common of these. Objective: To assess the efficacy/effectiveness of SMT for chronic headache through a systematic review of randomized clinical trials. Study Selection: Randomized clinical trials on chronic headache (tension, m igraine and cervicogenic) were included in the review if they compared SMT with other interventions or placebo. The trials had to have at least I pati ent-rated outcome measure such as pain severity, frequency, duration, impro vement, use of analgesics, disability, or quality of life. Studies were ide ntified through a comprehensive search of MEDLINE (1966-1998) and EMBASE (1 9741998). Additionally, all available data from the Cumulative Index of Nur sing and Allied Health Literature, the Chiropractic Research Archives Colle ction, and the Manual, Alternative, and Natural Therapies Information Syste m were used, as well as material gathered through the citation tracking, an d hand searching of nonindexed chiropractic, osteopathic, and manual medici ne journals. Data Extraction: Information about outcome measures, interventions and effe ct sizes was used to evaluate treatment efficacy. Levels of evidence were d etermined by a classification system incorporating study validity and stati stical significance of study results. Two authors independently extracted d ata and performed methodological scoring of selected trials. Data Synthesis: Nine trials involving 683 patients with chronic headache we re included. The methodological quality (validity) scores ranged from 21 to 87 (100-point scale). The trials were too heterogeneous in terms of patien t clinical characteristic, control groups, and outcome measures to warrant statistical pooling. Based on predefined criteria, here is moderate evidenc e that SMT has short efficacy similar to amitriptyline in the prophylactic treatment of chronic tension-type headache and migraine. SMT does not appea r to improve outcomes when added to soft-tissue massage for episodic tensio n-type headache. There is moderate evidence that SMT is more efficacious th an massage for cervicogenic headache, Sensitivity analyses showed that the results and the overall study conclusions remained the same even when subst antial changes in the prespecified assumptions/rules regarding the evidence determination were applied. Conclusions: SMT appears to have a better effect than massage for cervicoge nic headache. It also appears that SMT has an effect comparable to commonly used first-line prophylactic prescription medications for tension-type hea dache and migraine headache. This conclusion rests upon a few trials of ade quate methodological quality. Before any firm conclusions can be drawn, fur ther testing should be done in rigorously designed, executed, and analyzed trials with follow-up periods of sufficient length.