Impact of herbal medicines on physical impairment.

The usefulness of recording physical impairment during intervention studies in chronic low back patients has been questioned. A re-analysis of all of our studies investigating aqueous extracts of Harpagophytum procumbens and a proprietary ethanolic Salix extract for chronic non-specific low back pain revealed that the "physical impairment" component of the Arhus low back pain index changed very little during treatment despite appreciable changes in the other two components, "pain" and "disability", over time. For comparison, we also extracted data from the literature on the topical use of capsaicin, which showed the same thing. There may be little to lose from omitting the time-consuming assessments of "physical impairment" in studies of the (primarily analgesic) effectiveness of herbal preparations.