Clinical Question: Can a simple rule be used to predict which patients with low back pain will benefit from spinal manipulation?
Setting: Outpatient (specialty)
Study Design: Decision rule (validation)
Synopsis: This study was designed to validate a previously developed clinical decision rule to determine which patients with low back pain would benefit from spinal manipulation therapy. The high-velocity thrust manipulation therapy used in the study was not provided by a chiropractor or an osteopath, but by a physical therapist. The investigators enrolled 131 consecutive patients who were referred for physical therapy for the treatment of low back pain. Patients were an average age of 34 years and 40 percent were women.
The clinical decision rule used in this study was based on the following five questions: (1) Is the duration of the pain less than 16 days? (2) Is there no pain below the knee? (3) Is this patient’s score on the fear-avoidance beliefs questionnaire less than 19? (4) Is there at least one hypomobile segment in the lumbar spine? and (5) Is there at least one hip with greater than 35 degrees of internal rotation range of motion? The rule was applied to all patients but was not used to determine therapy. Instead, after the rule was calculated, one half of the patients were assigned to receive manipulation therapy and range-of-motion exercises for two sessions during the first week, followed by a low-stress aerobic and lumbar spine strengthening program weekly for another three weeks. The control group received the same frequency of treatment, but therapy was limited to the strengthening program. Patients in both groups were instructed to stay active.
Cure of low back pain was defined as an improvement on the Oswestry Disability Questionnaire of at least 50 percent from baseline. Using the rule, 47 (36 percent) of the 131 patients would have been referred for manipulation, and these patients were distributed evenly between the two treatment groups. After one week (two sessions), 44.3 percent of the patients receiving manipulation achieved success compared with 11.5 percent of patients in the control group (number needed to treat [NNT] = three; 95 percent confidence interval [CI], 2.2 to 5.7). After four weeks, 62.9 percent of treated patients versus 36.1 percent of control patients met the criteria for success (NNT = four; 95 percent CI, 2.4 to 10.4). In evaluation, a positive outcome on the rule was found to result in a likelihood ratio of 13.2 (3.4 to 52.1). If the rule had been used to select patients who likely would respond to manipulation therapy, the NNT would have been 1.3 (95 percent CI, 1.1 to 1.9) at one week and 1.9 (95 percent CI, 1.4 to 3.5) at four weeks.
Bottom Line: A clinical decision rule can be used to determine which patients with low back pain will benefit from two sessions of spinal manipulation given over one week. Compared with exercise treatment, spinal manipulation has an NNT of two if the rule is positive. The rule gives one point for an affirmative answer to each question, and scores of 4 or 5 (out of 5) predict response to spinal manipulation. (Level of Evidence: 1b)