Dry needling (DN) is widely used in the treatment of myofascial pain. The ultrasound (US) is essential for
diagnosing and treating soft tissue injuries, including the muscles, tendons, and nerves. In recent years, interest
in US-guided DN has been increasing. The US-guided DN is a technique involving needle insertion at the site
of injury, the simulation of tissue injury, and inflammation under US guidance. Such a process indicates the
needle insertion site to ensure it does not penetrate the adjacent tissue. The importance of this will be addressed
in this brief report.

dry needling, myofascial pain, ultrasound

Myofascial pain is usually characterized by the presence of one or more trigger points which are hard palpable nodules located within taut bands of skeletal muscles that can produce pain when compressed. They are also often the cause of referred pain, i.e., pain that affects another part of the body. Local twitch response to pressure is another sign and symptom of myofascial pain. This sign is not usually easily identifiable by non-experts. The medical history and physical examination are used to diagnose myofascial pain syndrome in daily practice [1].

Dry needling (DN), also known as myofascial trigger point DN, is an injection method used in the treatment of myofascial pain. In short, DN is the process of inserting a hypodermic needle into the body without injecting any substance [2]. DN treatment is usually performed with a blind method using anatomical landmarks. It is not always easy to manually identify the painful muscle knot, especially in the acute phase of the disease and in the presence of diffuse spasm.

Ultrasound (US) visualization of DN offers new insights into muscle function. With the recent introduction into the US treatment process, it has been discussed whether injecting with the blind method is the right approach. US guidance in minimally invasive interventional procedures provides significantly better results than blind needle insertion based solely on anatomical landmarks [3]. Some authors have even suggested that blind injection may be malpractice. In general, the US has become more and more important in musculoskeletal disorders in recent years. Ultrasonography is an essential method for the diagnosis and treatment of soft tissue injuries, including muscles, tendons, and nerves [4]. In sonographic evaluation, pertinent studies have shown that trigger points are defined as hypoechoic areas of different shapes (e.g., spherical, rounded, elliptical, or band-shaped). These hypoechoic areas should be targeted in DN treatment [5]. Figure 1 shows an example of US-guided DN, and Video 1 shows the local twitch response obtained during needling. In addition, the evaluation of the vascular environment around the trigger point will guide the treatment selection. The US is helpful in diagnosis, and sonoelastography is helpful in distinguishing the trigger point from the surrounding tissue. Sonoelastography can be used as a second-line examination if trigger points cannot be detected in the ultrasonographic evaluation performed after the anamnesis and examination [1].

US-guided DN is an injection method that involves inserting a needle into an injured site under US guidance. Such a procedure indicates the needle insertion site to ensure that it does not penetrate the adjacent tissue. When we used DN to treat a tissue problem, US scanners can be used to identify the damaged tissue to be treated, and then while imaging in real-time, the needle can be guided to the affected segment, preventing tissue degeneration, and stimulating healing. The process is very accurate and more likely to be successful [6].

Figure 1. Ultrasound (US)-Guided Dry Needling (DN)
The image shows an example of the ultrasound (US)-guided dry
needling method (A). US images were taken during needling, with
arrows indicating the needle, and needle tips indicating the trigger
points (circle) in the supraspinatus muscle (B).

Video 1. Local Twitch Response Obtained During Ultrasound-Guided Dry Needling
The video is available at https://doi.org/10.29760/APJP.202209_32(2).0005

Therefore, US-guided DN can be an effective treatment for patients with myofascial trigger points, especially those with pain in deep structures. The safety of DN, visualization of trigger points and local twitch response, and the insertion of the needle tip into deep muscle trigger points are the main reasons for using US-guided DN in myofascial pain syndrome. This issue raises two main questions: Why do you need US guidance? ● US guidance targets not only the pain but also the disability resulting from the structural impairment caused by a taut band that mechanically alters the function of all coworking muscles. ● Unlike conventional DN, local twitch responses can be easily observed in US-guided DN. To see twitch responses in conventional DN, the needle has to be pumped up and down several times. ● While US guidance allows for longer needle usage, conventional DN uses short needles (often 25–50 mm) to avoid complications. ● US guidance improves the accuracy of needle placement. ● US guidance allows injection into deep tissues. ● US guidance enhances patient safety when needling in the vicinity of viscera, pleura, vascular, or neural structures. ● US guidance enables techniques such as perineural needling to be performed. ● US guidance ensures that the joint is not entered. ● Performing DN treatment under US guidance can reduce the number of sessions. How to perform US-guided DN? ● First, the presence of a taut band and an active trigger point is determined with manual palpation. ● Then, the entire painful area (presumably the trigger point) and the surrounding tissue are evaluated with the US. The location of the trigger point, its depth, its characterization, the local vascularity, and the surrounding tissue are determined. ● After sonographic characterization of the hypoechoic nodule, sonopalpation should be performed in an attempt to reproduce the local or referred pain. ● If the device specifications are suitable, the trigger point is differentiated from the surrounding tissue with sonoelastography. ● DN injection is performed using the direct or indirect method. ● A twitch response can be obtained within the trigger point. During the injection, the trigger point may shrink or disappear. In conclusion, US assessment and guidance in myofascial pain appear to be a promising method that will better understand the disease process and make definitive interventions when needed.

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