Oriental medicine procedures such as acupuncture therapy and pharmacopuncture therapy are relatively safe and effective Oriental medicine treatments used with various methods, in various diseases. Interestingly, Oriental medicine procedures performed in high risk areas of the body may result in a risk of injuries being reported, particularly when insertion into a specific anatomical structure is performed. This limits performing Oriental medicine acupressure by palpation with the hand or using needling sensation to determine the accurate location (de qi) for the treatment.

Ultrasound imaging diagnostic apparatus are very efficient equipment that can visualize the internal anatomical structure of the human body using a harmless, non-invasive method. As well as diagnosis of disease, ultrasound can be a very useful guide for accurate and safe procedure during acupuncture therapy [1]. However, it is not feasible for Oriental medicine doctors to use ultrasound machines routinely due to limited access, and typically their use is restricted to needle therapy, electroacupuncture, acupotomy, and pharmacopuncture.

Thus, this study analyzed clinical research that used ultrasound-guided Oriental medicine using needle therapy, electroacupuncture, acupotomy and pharmacopuncture, to examine the research trends, both domestically and in foreign countries.

Ultrasound is a sound wave with elasticity, and there is a mechanical interrelationship between this and the body. In the sound wave, a wave is produced along the route of progress, and since energy decreases with distraction and heat, diminution takes place. Ultrasound imaging is made by detecting an echo reflected in the body tissue or on the interface, and the relative intensity of the reflected sound wave is displayed as the relative brightness of pixels in an image. Ultrasound imaging collects the direction of progress of this sound wave, the time of return after reflection and the echo intensity, and shows them as an image.

Medical ultrasound visualizes muscles, tendons and many internal organs, and their size, structure and pathological damage with a real-time tomographic scan, which provides diagnostic medical imaging [19]. Medical ultrasound measures the reflected wave returning from the interface of tissues using ultrasound frequencies at 1-10 MHz, which is a nondestructive and non-invasive process that allows procedures to be safely performed by locating blood vessels or nerves during acupressure treatments [5].

However, compared to the routine use ultrasound technology in Western medicine, ultrasound has not been widely used in Oriental medicine as studies are based on a theory of anatomical connectivity through the meridian systems and meridian muscles. In addition, Oriental medicine doctors find it difficult to approach the use of ultrasound technology due to accessibility in the clinic compared to Western medicine where ultrasound machines are readily available. This is despite the fact that ultrasound can show visible results throughout the process of patient treatment, and allow comparisons of before and after images. Subsequently, if ultrasound studies based on anatomical theory continue, it would be possible to visualize Oriental medicine therapy in progress. Internal diseases as well as several musculoskeletal diseases treated by Oriental medicine may be performed to a higher quality through ultrasound visualization.

Thus, the aim of this study was to understand the current research directions in ultrasound-guided Oriental medicine acupuncture, both at home and abroad through searching databases (PubMed, CNKI, KISS, NDSL, and OASIS) for clinical research on Oriental medicine acupressure using ultrasound.

The 17 selected articles were analyzed, and showed that research began to be published in China in 2004. Studies have consistently been published each subsequent year showing that there has been an increasing interest in ultrasound-guided procedures. Most studies were published in China, followed by 5 in Korea and one in the US, and since ultrasound was the first phase of search terms used, it was not surprising that most articles selected for this study were RCTs. There have been no studies published in Korea and the US since 2016, while studies have been published in China up until 2018. When the selected articles were analyzed by condition the most common was omalgia studies (6 articles), followed by knee pain (4 articles). Generally, ultrasound guidance was used to accurately locate, aiding the procedure to avoid side-effects like pneumothorax. The treatment method most commonly used was acupotomy therapy (11 articles) indicating that this therapy requires more accuracy and safety in procedures with deeper and broader regions and benefits from ultrasound guidance.

The range of frequencies of ultrasound in the studies was usually between 5-14 MHz. The range differed depending on the study, but it was found that usually, the ultrasound frequency was between 5-15 MHz to observe musculoskeletal systems or superficial organs whilst a frequency of between 3.5-5 MHz was used to observe abdominal organs. There were 10 articles that did not mention the frequency. Liu et al [18], who performed abdominal ultrasound, did not mention the frequency. To develop accurate methodology the ultrasound frequency used in studies should be published for the reproducibility of research.

Lee [20] observed a safe needling depth and morphological structure of the acupuncture points around the shoulder joint using musculoskeletal system ultrasound, while Kim et al [21] explored the reliability of ultrasound as a system to evaluate safe needling depths for abdominal acupoints and checked reproducibility throughout the study to measure the vertical distance of the Shang Wan-pancreas. Chen et al [22] measured the depth of jianjing (GB21) using ultrasound to prevent pneumothorax.

Studies using ultrasound from various fields have been reported in Oriental medicine. However, most are case reports or case series, and there are relatively few studies that systematically discuss these articles. The limitations of this study were that the number of articles was small (17) and that most studies were case reports or case series. However, it was found that ultrasound-guided Oriental medicine acupuncture has a constant effect and that ultrasound related studies have steadily been conducted since 2011. Thus, at this point when there is an increasing medical interest in ultrasound, it seems that it is necessary for the domestic Oriental medicine community to take more interest in it and conduct more studies. It is judged that it would be necessary to conduct studies utilizing various Oriental medicine interventions and research related to ultrasound that can be applied to domestic clinical practice in the future. This study would provide basic data for the design of more diversified and systematic clinical research by the domestic Oriental medicine community in the future.

Ultrasound is an auxiliary medical device used in various non-invasive procedures as well as for diagnostic purposes. This study has highlighted the fact that it is necessary to continue to conduct studies that broaden the range of applications of ultrasound and secure accuracy and safety of Oriental medicine acupuncture.

The search term for English, Korean and Chinese languages.

Flowchart of the trial selection process.

Example of Search Strategy (MEDLINE via PubMed).

Study Design of the Selected Articles by the Year of Publication.

Summary of the 17 Selected Articles.

Treatment Method by Disease in the Selected Articles.

Research Method by Treatment Method in the Selected Articles.