The descending pain modulation system predicts short term efficacy of
multimodal pain therapy - an observational prospective cohort study.
Postgrad Med 2022;
134:277-287. [PMID:
34895019 DOI:
10.1080/00325481.2021.2017646]
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Abstract
OBJECTIVES
Treating chronic pain patients with multimodal pain therapy (MMPT) alters perception, awareness, and processing of pain at multiple therapeutic levels. Several clinical observations suggest that the effects of therapy may go beyond the possible sum of each level of therapy and may be due to a central descending inhibitory effect measurable by conditioned pain modulation (CPM). Thus, we investigated whether CPM is able to identify a group of patients that benefit particularly from MMPT.
METHODS
This was an observational prospective cohort study. Patients were hospitalized on a special pain medicine ward with specially trained staff for 10 days. The patients were questioned and had investigations before and shortly after MMPT and were followed-up on 3 months post discharge. Before and after treatment, subjects were investigated via CPM and quantitative sensory testing (QST) as well as completing questionnaires. The study was registered in the German Clinical Trials Register (DRKS00006850).
RESULTS
During the study period of 24 months, 224 chronic pain patients were recruited. 51 percent of patients completed the study period. There was an improvement in overall groups regarding all domains assessed, lasting beyond the end of the intervention. Patients with a sufficient CPM effect, defined as a reduction in pain during the conditioning stimulus, at baseline did show a more pronounced reduction in mean pain ratings than those without. This was not the case 3 months after therapy. Furthermore, sufficient CPM was identified as a predictor for pain reduction using a linear regression model.
CONCLUSION
In conclusion, this study shows that while a heterogeneous group of patients with chronic pain disorders does sustainably benefit from MMPT in general, patients with a sufficient CPM effect do show a more pronounced decrease in pain ratings directly after therapy in comparison to those without.
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