Abstract
Background: There is evidence that spinal manipulation (SM) has therapeutic benefit in the treatment of back pain. However, there is still poor understanding of the physiological mechanism by which it achieves its therapeutic benefit. In order to explore the mechanism of SM, this study explored it’s immediate anti-nociceptive effect, by measuring the pressure pain threshold (PPT) in spinal muscles pre and post SM, in subjects with low back pain.
Methods: A group of low back pain patients (n=60) were randomised into two groups, one received a SM to a dysfunctional segment in the lumbar spine. The second group received a sham procedure, where the patient was placed in a similar ‘wind up’ position, but the thrust applied non-specifically through the low back. Algometry measurements were taken over four spinal muscles (iliocostalis, multifidus, glutei and trapezius), before and after the manipulation or sham procedure.
Results: Paired t-tests for within group differences showed statistically significant differences for the SM group iliocostalis (p< 0.001) multifidus (p< 0.001) glutei (p< 0.001) and trapezius (p=0.20) with small to moderate effect size (0.60; 0.58; 0.36 & 0.20 respectively) small between group differences were also noted. There were no significant changes in PPT in any muscle in response to the sham procedure.
Conclusion: SM produced a statistically significant change in PPT with a small to medium effect size. No changes were observed in the sham and thus the active component of SM appears to be related to the specific manipulative thrust technique rather than to the general handling and positioning of the patient.
Correspondence should be addressed to Mr J. O’Dowd, Honorary Secretary at SBPR c/o BOA, Royal College of Surgeons, 35–43 Lincoln’s Inn Fields, London, WC2A 3PE.
