The effect of spinal manipulative therapy on experimentally induced pain: a systematic literature review

Abstract

BackgroundAlthough there is evidence that spinal manipulative therapy (SMT) can reduce pain, the mechanisms involved are not well established. There is a need to review the scientific literature to establish the evidence-base for the reduction of pain following SMT.ObjectivesTo determine if SMT can reduce experimentally induced pain, and if so, if the effect is i) only at the level of the treated spinal segment, ii) broader but in the same general region as SMT is performed, or iii) systemic.DesignA systematic critical literature review.MethodsA systematic search was performed for experimental studies on healthy volunteers and people without chronic syndromes, in which the immediate effect of SMT was tested. Articles selected were reviewed blindly by two authors. A summary quality score was calculated to indicate level of manuscript quality. Outcome was considered positive if the pain-reducing effect was statistically significant. Separate evidence tables were constructed with information relevant to each research question. Results were interpreted taking into account their manuscript quality.ResultsTwenty-two articles were included, describing 43 experiments, primarily on pain produced by pressure (n = 27) or temperature (n = 9). Their quality was generally moderate. A hypoalgesic effect was shown in 19/27 experiments on pressure pain, produced by pressure in 3/9 on pain produced by temperature and in 6/7 tests on pain induced by other measures. Second pain provoked by temperature seems to respond to SMT but not first pain. Most studies revealed a local or regional hypoalgesic effect whereas a systematic effect was unclear. Manipulation of a “restricted motion segment” (“manipulable lesion”) seemed not to be essential to analgesia. In relation to outcome, there was no discernible difference between studies with higher vs. lower quality scores.ConclusionsThese results indicate that SMT has a direct local/regional hypoalgesic effect on experimental pain for some types of stimuli. Further research is needed to determine i) if there is also a systemic effect, ii) the exact mechanisms by which SMT attenuates pain, and iii) whether this response is clinically significant.

Determining the level of evidence for the effectiveness of spinal manipulation in upper limb pain: A systematic review and meta-analysis

“…Furthermore, this review included postgraduate theses which are often not taken into account. Based on these new findings, the current results do not support previous findings in those patients that SM may have the distal analgesic effect (Coronado et al, 2012;Millan et al, 2012), although there is a concern about small number of included studies.…”

“…In the study by Winters et al (1997) pain in the superior part of the trapezoid muscle and scapular region was included, although such pain could be caused by cervical disorders (Dwyer et al, 1990;Grubb and Kelly, 2000). In other recent reviews, Coronado et al (2012) investigated the analgesic effects of SM and Millan et al (2012) examined those of spinal manipulative therapy including both SM and spinal mobilization. Whereas these reviews included only studies investigating the effect of SM or spinal manipulative therapy on experimentally induced pain regardless of whether subjects are symptomatic, the current review only included those examining pain changes in clinical populations.…”

Analgesic effects of manual therapy in patients with musculoskeletal pain: A systematic review

“…Manual therapy techniques can play a role in these interactions as they trigger a cascade of neurophysiological events starting from some form of mechanical (manual) stimulation of the body (Bialosky 2008). Evidence for these neurophysiological events comes from clinical research which show increases in pain thresholds (PTs) directly after spinal manual therapy interventions in healthy participants, in participants subjected to experimentally induced pain, and in patients with musculoskeletal pain (Coronado et al 2012, Millan et al, 2012. In the reviews of Millan and colleagues (2012) and Coronado and colleagues (2012), it was concluded that manual therapy techniques carried out at the spinal column have significant pain modulating effects, although the clinical relevance of these effects remain unclear.…”

The Within-Session Change in Low Back Pain Intensity Following Spinal Manipulative Therapy Is Related to Differences in Diffusion of Water in the Intervertebral Discs of the Upper Lumbar Spine and L5-S1

“…47 It is hypothesized, but not definitely proven, that these thrusts create a stimulus to spinal tissues that may result in analgesia. 12,20,22,50 A large body of research has generally supported efficacy and effectiveness of SMT for the treatment of LBP, with overall effect-size improvements in pain following SMT that are typically modest when compared to placebo treatment or to no treatment at all. 16,19,33,[36][37][38]42,55,59,62 These findings suggest a heterogeneous response between patients receiving SMT.…”