Endoscopic submucosal dissection (ESD) has become the widely accepted and minimally invasive therapy of choice for superficial gastrointestinal (GI) tumors (1–3). ESD is an efficient therapeutic endoscopic procedure with a high en bloc resection rate and lower local recurrence rate compared to endoscopic mucosal resection (4, 5). However, ESD is technically challenging because it is associated with prolonged procedure time and several adverse events. The most common complications of ESD are perforation and bleeding (6, 7). In addition, it also requires stricter access conditions and longer learning curve than endoscopic mucosal resection which limits the worldwide popularity, especially in the United States and Western Countries (8, 9).

The major cause of complications in ESD procedure is that the visibility of the dissection plane is not secured because of the mucosal flap (10). Appropriate tissue tension and clear visibility of the tissue to be dissected using traction are essential for effective and safe ESD procedure. Although, the use of a transparent cap and reduplicative submucosal injection before the next resection is beneficial to obtain clear visibility of the submucosal layer. However, the supporting capacity of cap is limited and repeated injections prolong the procedure time. Another simple method is to change the patient’s position during the procedure for adequate tissue tension, but when the lesion is in the upper GI tract, the optimal position is limited. Although expert and experienced endoscopists can perform the endoscopic resection using superior dexterity gained from rich experience, unskilled endoscopists commonly find it technically demanding and difficult to complete the resection without good visibility of the dissection plane. The lack of a controllable second hand in ESD is a major difference compared with laparoscopic surgery which has three ports to assist the procedure.

Inspired by the surgical pull and push techniques, traction technology arisen and was applied as a “second-hand” for endoscope (11). With the assistant of some accessories, it can not only provide a clear view of submucosal tissue and vessel for operation but also gets adequate tissue tension, which facilitates ESD to be more effective and safer. In recent years, traction techniques have developed rapidly, including clip-with-snare traction, clip-with-line traction, magnetic anchor traction, percutaneous traction, external forceps traction, and internal-traction method (12–15). Although, these techniques are effective for simple counter traction, but they are still restricted in terms of being able to regulate the direction of the traction, change the submucosal layer’s tension, and re-grasping of the tissue. Some of these techniques are also invasive and only effective in certain regions of the GI tract. Endoscopic use of flexible robotic arms may aid the operator in getting over the ESD procedure’s technical challenges (16). Robot-assisted ESD is a desirable traction technique, and several kinds of endoscopic robots that permit bimanual operation are currently being developed. A new era of endoscopic surgery with robot assistance has begun. The goal of this study is to compare robotic and non-robotic endoscopic traction techniques in endoscopic submucosal dissection, as well as to review their development and characteristics.

Endoscopic submucosal dissection is a landmark technique in the development of endoscopic therapy and has been rapidly promoted. Although endoscopic submucosal dissection is an effective therapy for superficial lesions in the GI tract, it is challenging and requires a high degree of skill levels, which might hinder its execution and raise the possibility of complications (27, 28). The current ESD procedure carries the high risk of complications such as bleeding and perforation resulting from blind dissection. This is because a standard endoscope has inherent limitations in maintaining visualization of the submucosal dissection plane due to its one-handed operation capacity. A long period of training is required for endoscopists because they must undergo extensive training before they can perform ESD in a secure and expert manner. Variety of non-robotic traction techniques have been emerged to overcome these limitations with the goal of achieving proper counter traction. These traction techniques can achieve good, clear visualization of the submucosal layer using only a few, easy-to-configure components. However, they are constrained by the fact that the direction of traction cannot be changed, and the modification process is difficult because re-grasping is not allowed (29–31). Moreover, the tension of traction can reduce over time in some of these techniques. Robot-assisted traction in endoscopic submucosal dissection is another attempt to mitigate this difficulty.

Various endoscopic robot systems with twin arms that can be operated bimanually are currently available in the market. Robotic systems have shown success in therapeutic endoscopic operations, but the development of specially tailored endoscopes and tools had delayed their widespread clinical use. According to several investigations, it is theoretically possible to do endoscopic submucosal dissection using a simple robot that enables the endoscopist to dynamically apply counter traction. In comparison to conventional non-robotic procedures, robotic-assisted traction could significantly shorten the duration of the surgery and obtain a greater rate of direct vision dissection. Robotic-assisted traction is simple to implement into clinical practice and decreases the learning curve of endoscopic submucosal dissection for beginners. Additionally, it enables the endoscopist to carry out standard endoscopic submucosal dissection. Consequently, further research into the robotic-assisted traction strategy is necessary.

Study concept and design: ZM, ZH. Manuscript writing: ZM, ZH, SR. Collection, analysis and interpretation of data: BD, LL, YN. Critical revision of manuscript: ZM, SR. All authors contributed to the article and approved the submitted version.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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