title: 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; 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 low back pain 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 2 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 2 weeks of participation in the study. Immediate attenuation of suprathreshold heat response was greatest following SMT (P = .05, partial η(2) = .07). Group-dependent differences were not observed for changes in pain intensity and disability at 2 weeks. Participant satisfaction was greatest following the enhanced placebo SMT. This study was registered at www.clinicaltrials.gov under the identifier NCT01168999.
  
  
  CONCLUSIONS
  The results of this study indicate attenuation of pain sensitivity is greater in response to SMT than the expectation of receiving an SMT. These findings suggest a potential mechanism of SMT related to lessening of central sensitization and may indicate a preclinical effect beyond the expectations of receiving SMT.
authors.affiliation: Department of Physical Therapy, Center for Pain Research and Behavioral Health, University of Florida, Gainesville, Florida. Electronic address: bialosky@phhp.ufl.edu.
authors.forename: Joel E
authors.initials: JE
authors.lastname: Bialosky
authors.affiliation: Department of Physical Therapy, Center for Pain Research and Behavioral Health, University of Florida, Gainesville, Florida.
authors.forename: Steven Z
authors.initials: SZ
authors.lastname: George
authors.affiliation: Department of Physical Therapy, University of Florida, Gainesville, Florida.
authors.forename: Maggie E
authors.initials: ME
authors.lastname: Horn
authors.affiliation: Oral and Maxillofacial Surgery, Division of Neuroscience, University of Florida, Gainesville, Florida.
authors.forename: Donald D
authors.initials: DD
authors.lastname: Price
authors.affiliation: Department of Medicine, University of Florida, Gainesville, Florida.
authors.forename: Roland
authors.initials: R
authors.lastname: Staud
authors.affiliation: Department of Clinical and Health Psychology, Center for Pain Research and Behavioral Health, University of Florida, Gainesville, Florida.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Robinson
mesh_terms: D000328:Adult; D059333:Central Nervous System Sensitization; D004185:Disability Evaluation; D005260:Female; D006358:Hot Temperature; D006801:Humans; D017116:Low Back Pain / Q000523:psychology / Q000628:therapy*; D008297:Male; D026201:Musculoskeletal Manipulations / Q000523:psychology; D010147:Pain Measurement; D017288:Pain Threshold; D017060:Patient Satisfaction; D011795:Surveys and Questionnaires; D013997:Time Factors; D016896:Treatment Outcome
keywords: Central sensitization; low back pain; manual therapy; placebo; spinal manipulation