Spinal Manipulative Therapy–Specific Changes in Pain Sensitivity in Individuals With Low Back Pain (NCT01168999)

Abstract

Spinal Manipulative Therapy (SMT) is effective for some individuals experiencing low back pain (LBP); however, the mechanisms are not established regarding the role of placebo. SMT is associated with changes in pain sensitivity suggesting related altered central nervous system response or processing of afferent nociceptive input. Placebo is also associated with changes in pain sensitivity and the efficacy of SMT for changes in pain sensitivity beyond placebo has not been adequately considered. We randomly assigned 110 participants with LBP to receive SMT, placebo SMT, placebo SMT with the instructional set, “The manual therapy technique you will receive has been shown to significantly reduce low back pain in some people”, or no intervention. Participants receiving the SMT and placebo SMT received their assigned intervention 6 times over two weeks. Pain sensitivity was assessed prior to and immediately following the assigned intervention during the first session. Clinical outcomes were assessed at baseline and following two weeks of participation in the study. Immediate attenuation of suprathreshold heat response was greatest following SMT (p= 0.05, partial η2= 0.07). Group dependent differences were not observed for changes in pain intensity and disability at two week. Participant satisfaction was greatest following the enhanced placebo SMT.

What Effect can Manual Therapy have on a Patient’s Pain Experience?

“…MT appears to also modify the state of spinal excitability as indicated by immediately decreased nociceptive flexion reflexes [40] and reduced temporal sensory summation [10,41], representing a combination of reduced facilitation and increased inhibition of nociceptive input in the CNS. Systematic reviews also indicate reductions in pressure pain thresholds in response to both joint and muscle/connective tissue biased MT [35,42].…”

“…Studies have been performed in several different musculoskeletal disorders; for example, low back pain [10], shoulder pain [11] and cervical pain [12]. These studies of MT have mainly focused on providing direct evidence supporting its clinical effects [13] with the primary outcome being reduction in both pain at rest and pain with activity.…”

Placebo disclosure does not result in negative changes in mood or attitudes towards health care or the provider

“…The current study is a secondary analysis of a previously completed randomized controlled trial [33]. The study was approved by the Institutional Review Board of the trust the experimenters in this study?…”

“…The entire study procedure is described in detail elsewhere [33]. Briefly, participants receiving the SMT and both placebo treatment groups were scheduled for 5 additional sessions during the next 2 weeks to receive their assigned intervention.…”

“…This need for deception has raised significant ethical issues regarding the use University of Florida. Details of the study design and primary analyses are reported in more detail elsewhere [33]. Briefly, we recruited a sample of convenience from the general community of the University of Florida campus and Health Science Center.…”