Delineating inflammatory and mechanical sub-types of low back pain: a pilot survey of fifty low back pain patients in a chiropractic setting

BACKGROUND: An instrument known as the Mechanical and Inflammatory Low Back Pain (MAIL) Scale was drafted using the results of a previous expert opinion study. A pilot survey was conducted to test the feasibility of a larger study designed to determine the MAIL Scale's ability to distinguish two potential subgroups of low back pain: inflammatory and mechanical. METHODS: Patients with a primary complaint of low back pain (LBP) presenting to chiropractic clinics in Perth, Western Australia were asked to fill out the MAIL Scale questionnaire. The instrument's ability to separate patients into inflammatory and mechanical subgroups of LBP was examined using the mean score of each notional subgroup as an arbitrary cut-off point. RESULTS: Data were collected from 50 patients. The MAIL Scale did not appear to separate cases of LBP into the two notionally distinct groups of inflammatory (n = 6) or mechanical (n = 5). A larger "mixed symptom" group (n = 39) was revealed. CONCLUSIONS: In this pilot study the MAIL Scale was unable to clearly discriminate between what is thought to be mechanical and inflammatory LBP in 50 cases seen in a chiropractic setting. However, the small sample size means any conclusions must be viewed with caution. Further research within a larger study population may be warranted and feasible.