Centralization of low back pain and perceived functional outcome.

McKenzie's methods for evaluating and treating low back pain are used often but studied little. When using the McKenzie system, it is important to observe signs of symptom movement to a central location (centralization). This study investigated the relationships between centralization of low back pain and/or radiculopathy and the subjects' rating of functional outcome. Thirty-six subjects with low back pain volunteered to participate and were evaluated and treated by six researchers. Subjects were tested initially and again 14 days after initiation of treatment using the Oswestry Low Back Pain Disability Questionnaire and the Performance Assessment and Capacity Testing Spinal Function Sort (SFS). Symptoms were monitored for the occurrence of "complete centralization." Of the 36 subjects, 25 showed complete centralization within 14 days. The SFS score changes were significantly higher for subjects who completely centralized (p = 0.015). The results supported the hypothesis that subjects who centralize will have improved functional outcome and, thus, quality of life. However, shorter time to occurrence of complete centralization does not necessarily correlate with improved outcome.