Effect assessment of acupotomy on myofascial pain syndrome of trapezius muscle based on portable shear wave elastography

To provide the evidence for quantitative assessment of clinical diagnosis of myofascial pain syndrome (MPS) of trapezius muscle and the therapeutic effect of acupotomy, utilizing portable shear wave elastography (SWE).

A total of 49 subjects (including 21 cases of unilateral trapezius MPS, 20 cases of bilateral trapezius MPS and 8 healthy subjects) were recruited, including 98 trapezius samples. According to whether pain occurred or not, they were divided into an observation group (61 samples) and a control group (37 samples). The cases in the observation group were subdivided into an observation subgroup 1 (14 samples) and an observation subgroup 2 (47 samples) based on whether acupotomy was received. In the observation subgroup 1, under ultrasound guidance, only 1 intervention with acupotomy was performed to release the deep and superficial fascia layers of the trapezius muscle. In the observation subgroup 2 and the control group, no treatment was delivered. Before treatment, the shear modulus (G-value) and the score of visual analogue scale (VAS) were compared between the observation group and the control group, and the receiver operating characteristic (ROC) curve was plotted to determine the optimal diagnostic threshold of trapezius MPS. The G-value and VAS score were compared before and after treatment in the observation subgroup 1, and the therapeutic effect of acupotomy was assessed.

The G-value and VAS score in the observation group were higher than those in the control group (P＜0.05) before treatment. For the diagnosis of trapezius MPS, the optimal diagnostic threshold of G-value was 9.08 kPa, yielding a specificity of 83.78% and a sensitivity of 75.41%. In the observation subgroup 1, both G-value and VAS score decreased after treatment in comparison with those before treatment (P＜0.05).

Acupotomy may improve the elasticity of the trapezius muscle and obtain the immediate therapeutic effect on trapezius MPS in patients. The portable SWE holds the promise for the objective evaluation of clinical diagnosis and therapeutic effect on trapezius MPS.