Therapeutic Contextual Factors in Physiotherapy: Magnitude, Mechanisms and Contributors of Placebo Mediated Analgesia in Chronic Low Back Pain

• Author / Creator

  Fuentes Contreras, Jorge Patricio

• Mechanisms through which physiotherapy influence musculoskeletal pain include both the specific ingredient of an intervention as well as contextual factors inherent to clinical encounters including the therapist, patient and setting. These contextual factors are often termed “non-specific” effects and are associated with the placebo effect. Although well documented in other areas, the impact of contextual factors in treatment of low back pain (LBP) is unknown. In addition, the contributors to the physiotherapy placebo response in LBP have not been elucidated.
  This project investigated the effect of contextual factors in patients with LBP receiving either active or sham interferential current therapy (IFC). Determinants of a favorable response to the placebo response were also explored. A sample of 117 chronic LBP participants were randomly assigned into 4 groups: active limited (AL) included the application of active IFC in a limited therapeutic encounter (i.e. limited patient-practitioner interaction), sham limited (SL) included sham IFC in a limited therapeutic encounter, active enhanced (AE) included active IFC in an enhanced therapeutic encounter (i.e. supportive patient-practitioner relationship, encouragement), and sham enhanced (SE) included sham IFC in an enhanced therapeutic encounter. Outcomes included pain intensity (PI-NRS) and muscle pain sensitivity (PPT). Analysis included MANOVA, and logistic regression. Also, clinical significance was determined.
  There were statistically significant differences between groups on PPT’s and PI-NRS (baseline and after treatment). Mean differences in PI-NRS were 18.3 mm, 10.0 mm, 31.4 mm, and 22.2 mm, for the groups AL, SL, AE, and SE respectively. Clinically important effect sizes were found. Mean differences in PPT’s were 1.2 kg, 0.3 kg, 2.0 kg, and 1.7 kg for the group AL, SL, AE, and SE respectively. Again, clinically important effect sizes were found. The level of therapeutic alliance and pain duration were the factors associated with the placebo response.
  Results highlight the important role of contextual factors in the treatment of patients with chronic LBP. Enhanced therapeutic relationship was associated with meaningful clinical improvement. Also, perceived therapeutic alliance was associated with placebo response. Factors other than the specific ingredient of a treatment may have a large role in achieving positive clinical outcomes, and exploring them is central to physiotherapy practice.

• Subjects / Keywords

  • Pain
  • Physiotherapy
  • Low back pain
  • Placebo

• Graduation date

  Spring 2013

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3H70X

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.