J Manipulative Physiol Ther. 1992 Oct; 15(8): 487-94.

The efficacy of chiropractic manipulation for back pain: blinded review of relevant randomized clinical trials.

Assendelft WJ, Koes BW, van der Heijden GJ, Bouter LM.

Department of Epidemiology and Biostatistics, University of Limburg, Maastricht, The Netherlands.

OBJECTIVE: To assess the efficacy of chiropractic for patients with back pain. DATA SOURCES: Randomized clinical trials (RCTs) on spinal manipulation were identified with a Medline search (1966-1990), by citration tracking, and by manual examination of the relevant chiropractic reference systems [Chiropractic Research Archives Collection and Index to Chiropractic Literature]. [Indexing terms, Medline; backache, musculoskeletal diseases, manipulation, osteopathy or chiropractic in combination with evaluation studies, outcome and process assessment, prospective studies, comparative studies, clinical trials or double blind method. Indexing terms, Chiropractic Research Archives Collection: backache therapy-chiropractic clinical trials, cost benefit analysis, evaluation studies--chiropractic, manipulation--spinal, prospective studies, sciatica-therapy. Indexing terms, Index to Chiropractic Literature, backache therapy, clinical trials, cost benefit analysis, intervertebral disc displacement-therapy.] STUDY SELECTION: All RCTs involving chiropractors as therapists. To find additional evidence from nonchiropractic RCTs, chiropractic standards similar to the type of treatment used in nonchiropractic trials were determined by a panel of blinded chiropractors. DATA EXTRACTION: Review by two blinded reviewers independently, using a list of methodological criteria, each of which was attached to a weight. The maximum was set at 100 points. DATA SYNTHESIS: We identified five chiropractic RCTs. No similarity to chiropractic standards could be detected in any of the nonchiropractic RCTs. No chiropractic RCT had a methodological score of more than 50 points. The authors of four of the trials report favorable results for chiropractic, while one refrains from drawing conclusions. The results of the chiropractic RCTs differed on the timing of maximal effect as well as on the subgroups showing the best treatment results. CONCLUSIONS: Although the small number of chiropractic RCTs and the poor general methodological quality precludes the drawing of strong conclusions, chiropractic seems to be an effective treatment of back pain. However, more studies with a better research methodology are clearly still needed.