We also investigated the usability of SWE for evaluating the efficacy of a stretching exercise program.
Ĭonsidering this information, we investigated whether SWE can detect latent TrPs as well as active TrPs in MPS and whether it may contribute to the diagnosis of MPS in the upper part of the trapezium muscle. Due to the ability of detecting micro-environmental changes earlier than ultrasound and providing quantitative information about tissue stiffness, the utilization of SWE has been increasing day by day. Although there are several techniques, the most reliable elastography method is shear wave elastography (SWE). US elastography has been widely used in many tissues and organs, including the breast, thyroid, liver, and muscles/tendons. The stiffness of these muscles can be determined by US elastography. The resting stiffness of the muscles involved in TrPs is high.
Although some alternative therapies such as dry needling, analgesic injection, non-steroidal anti-inflammatory drugs (NSAID), acupuncture, or Botulinum toxin A are used in treatment, stretching exercises are the basis of MPS treatment. The main objective of treatment is breaking this cycle. This vicious cycle causes excessive stimulation of nociceptors and hence pain. Hypoperfusion/ischaemia due to excessive muscle contraction lead to increased mediators and acidification triggering a vicious cycle. According to the motor phenomenon, increased acetylcholine (ACh) in the motor end plate leads to permanent depolarization of the muscle fibre membrane, resulting in excessive muscle contraction. The pathophysiology of MPs is not fully known. Therefore, early diagnosis and treatment before clinical activation is very important. Latent TrPs can be transformed into active form and cause clinical symptoms. A Latent TrP has all the features of a TrP but is clinically silent. If a TrP spontaneously triggers pain, it is called ‘Active TrP’. TrPs causing MPS can be active or latent.
Although there have not been generally accepted definitive diagnostic criteria, the diagnosis of MPS is based on the detection of these TrPs. The characteristic finding of MPS is the painful TrPs due to the sensitivity of nodules within the taut bands of the skeletal muscle. The aetiology of MPS is not yet fully understood. The most commonly affected muscle in the neck-shoulder girdle in MPS is the trapezius muscle. In contrast to fibromyalgia, which is a generalized pain syndrome, MPS is limited to a specific body area. Myofascial pain syndrome (MPS), previously called muscular rheumatism and non-joint rheumatism, is a soft tissue pain syndrome characterized by local and/or directed pain originating from trigger points (TrPs).