El efecto en el umbral del dolor de un miotoma tras la manipulación vertebral del nivel correspondiente, ¿es influenciable por las expectativas del sujeto?

Introduction

Pain is a complex perception that comprehends a variable proportion of nociceptive input. Not only involves an unpleasant experience, it also has an emotional impact on its relevance and a cognitive component over its origin. The cognitive component builds up over the years influenced by own experiences of pain, observing of other people's experiences and expert information. The expectations and believes that lead from that learning process create a positive (placebo) and negative (nocebo) potential modulation.

Material and methods

A randomized, double-blinded, clinical trial with control group is carried out. Both groups received a vertebral manipulation (VM), but the experimental group is provided with information that generates expectations of improvement after the manipulation. 98 patients were included in the study. These patients presented trigger points (TP) in latent state on the superior trapezius related to a C3 homolateral lesion on extension-rotationsidebending (ERS). Changes on pain perception on the TP were quantified through algometry and visual analogical scale (VAS).

Results

The experimental group shows a better improvement in the two parameters. Both values showed a tendency to statistical significance: P =.09 for pain threshold and 0,05 for VAS.

Conclusions

The initial hypothesis is rejected. It would be advisable to carry out similar trials on other pathologies that occur with chronic spontaneous pain, since believes and expectations of improvement on these cases could have higher impact on pain modulation.