Is early diagnosis of myofascial pain syndrome possible with the detection of latent trigger points by shear wave elastography?

Introduction
The aim of the study was to investigate the contribution of shear wave elastography to the diagnosis of myo­fascial pain syndrome (MPS) of the upper part of the trapezius.

Material and methods
Ethical committee approval was obtained for the study. Thirty volunteer women with trigger points in the upper part of the trapezius muscle and 30 healthy women with a similar age distribution were included in the study. The patient group performed a self-stretching exercise program for 4 weeks. No intervention was applied to the control group. Muscle stiffness values of both groups were evaluated with shear wave elastography (SWE), and pain levels of all volunteers were evaluated by the Visual Analogue Scale at the beginning and the end of the study. The statistical analyses were performed using SPSS version 18.0.

Results
There was a significant decrease after the treatment in terms of upper trapezius muscle stiffness and the pain levels in the patient group (p < 0.001 and p < 0.001). In the patient group, there was a moderate correlation between the decrease in the pain level and the reductions in muscle stiffness (r = 0.595). In control group, there was no significant difference in terms of both muscle stiffness and pain levels before and after treatment (p > 0.05).

Conclusions
SWE is a reliable method for detecting latent trigger points in MPS, and it can be used for evaluating the response to treatment.