Controlled clinical trials of manipulation: a review and a proposal.

Manipulation has been widely used for the treatment of back disorders for centuries. However, until recently, randomized clinical trials have not been used to study the effectiveness of the various forms of manipulation. A review of recently published clinical trials indicates that manipulation is probably superior to certain control or sham treatments. This review also indicates that further randomized clinical trials are desirable and suggests the features that will be necessary in future trials of manipulation.