Muhsen A1,2, Moss P1, Gibson W3, Walker B4, Schug S5, Wright A1
1Curtin University, School of Physiotherapy and Exercise Science, Perth, Australia, 2Hashemite University, School of Physical and Occupational Therapy, Zarqa, Jordan, 3University of Notre Dame Australia, School of Physiotherapy, Fremantle, Australia, 4Murdoch University, School of Health Professions, Perth, Australia, 5University of Western Australia, Department of Anaesthesiology, Perth, Australia
Background: Endogenous Analgesia (EA) generally involves multiple central circuits that modulate pain inhibition. Recent research evidence suggests that Conditioned Pain Modulation (CPM) and Manual Therapy (MT) activate EA mechanisms to mediate their analgesic effects. The association between the CPM and MT analgesia has not been previously investigated.
Purpose: The main aim of this study was to assess the association between CPM and MT analgesia in patients with Lateral Epicondylalgia (LE). We also sought to investigate whether there was a difference in MT analgesia between those who did and who did not demonstrate a clear CPM effect (i.e. CPM responders and non-responders).
Methods: In a quasi-experimental single-group pretest-posttest study design, 70 participants with LE were initially assessed in a single session for CPM followed by MT with 15 minute rest in between. A single assessor (ICC (3,4)=0.99) measured pressure pain threshold (PPT) at the elbow and wrist of the symptomatic side before, during, and after cold water immersion (10°C) of the other arm and contralateral cervical lateral glide (CLG) mobilisation. Based on the level of CPM response, participants were assigned post hoc into two CPM groups: responders and non-responders. Linear mixed models (LMDs) were used to evaluate differences in CPM and MT responses between time points in both groups. Pearson partial correlations and regression analyses were also used to examine the association between CPM and MT PPT measures whilst controlling for baseline PPT measures. Separate LMDs were then used to evaluate differences in MT analgesia overtime between CPM groups controlling for Patient Rated Tennis Elbow Evaluation (PRTEE) scores and gender.
Results: Both CPM responder and non-responder groups demonstrated significant increase in PPT measures during and post CPM and MT over the wrist and elbow testing sites (p 0.001). There were also significant moderate positive partial linear correlations (r: 0.32-0.53, P 0.05) between CPM and MT PPT measures. The regression analyses showed that CPM PPT was a significant predictor of MT PPT (p 0.001) measured at both sites over different time points and the models explained between 71% and 89% variability in MT PPT. Lastly, there were significant differences in MT PPT measures between CPM groups overtime, during and post CLG mobilisation (P= 0.014-0.033), with significantly higher MT PPT responses observed at both testing sites among CPM responders.
Conclusion(s): The study showed that CPM and MT analgesic responses were significantly correlated in a sample population with LE. CPM responders demonstrated significantly higher levels of MT analgesia compared to CPM-non responders. This suggests that both forms of analgesia share similar neuro-physiological mechanism. Further research is recommended into longer term changes of CPM and MT analgesia and in various musculoskeletal pain conditions.
Implications: The study provides strong evidence of the analgesic effects of CLG in immediately reducing pain in LE. It has also improved our knowledge of the mechanism of action of MT. This study will therefore lay the foundation for future clinical trials that will investigate/compare the impact of different treatment interventions on CPM and MT responses.
Keywords: conditioned pain modulation, lateral epicondylalgia, manual therapy analgesia
Funding acknowledgements: PhD project funded by the Hashemite University, Jordan. Also supported by the School of Physiotherapy and Exercise Science, Curtin University.
Purpose: The main aim of this study was to assess the association between CPM and MT analgesia in patients with Lateral Epicondylalgia (LE). We also sought to investigate whether there was a difference in MT analgesia between those who did and who did not demonstrate a clear CPM effect (i.e. CPM responders and non-responders).
Methods: In a quasi-experimental single-group pretest-posttest study design, 70 participants with LE were initially assessed in a single session for CPM followed by MT with 15 minute rest in between. A single assessor (ICC (3,4)=0.99) measured pressure pain threshold (PPT) at the elbow and wrist of the symptomatic side before, during, and after cold water immersion (10°C) of the other arm and contralateral cervical lateral glide (CLG) mobilisation. Based on the level of CPM response, participants were assigned post hoc into two CPM groups: responders and non-responders. Linear mixed models (LMDs) were used to evaluate differences in CPM and MT responses between time points in both groups. Pearson partial correlations and regression analyses were also used to examine the association between CPM and MT PPT measures whilst controlling for baseline PPT measures. Separate LMDs were then used to evaluate differences in MT analgesia overtime between CPM groups controlling for Patient Rated Tennis Elbow Evaluation (PRTEE) scores and gender.
Results: Both CPM responder and non-responder groups demonstrated significant increase in PPT measures during and post CPM and MT over the wrist and elbow testing sites (p 0.001). There were also significant moderate positive partial linear correlations (r: 0.32-0.53, P 0.05) between CPM and MT PPT measures. The regression analyses showed that CPM PPT was a significant predictor of MT PPT (p 0.001) measured at both sites over different time points and the models explained between 71% and 89% variability in MT PPT. Lastly, there were significant differences in MT PPT measures between CPM groups overtime, during and post CLG mobilisation (P= 0.014-0.033), with significantly higher MT PPT responses observed at both testing sites among CPM responders.
Conclusion(s): The study showed that CPM and MT analgesic responses were significantly correlated in a sample population with LE. CPM responders demonstrated significantly higher levels of MT analgesia compared to CPM-non responders. This suggests that both forms of analgesia share similar neuro-physiological mechanism. Further research is recommended into longer term changes of CPM and MT analgesia and in various musculoskeletal pain conditions.
Implications: The study provides strong evidence of the analgesic effects of CLG in immediately reducing pain in LE. It has also improved our knowledge of the mechanism of action of MT. This study will therefore lay the foundation for future clinical trials that will investigate/compare the impact of different treatment interventions on CPM and MT responses.
Keywords: conditioned pain modulation, lateral epicondylalgia, manual therapy analgesia
Funding acknowledgements: PhD project funded by the Hashemite University, Jordan. Also supported by the School of Physiotherapy and Exercise Science, Curtin University.
Topic: Musculoskeletal: upper limb
Ethics approval required: Yes
Institution: Curtin University
Ethics committee: Human Research Ethics Committee
Ethics number: HRE2017-0198-02
All authors, affiliations and abstracts have been published as submitted.
