What we want for ESD is a second hand! Traction method

A Novel Retractable Robotic Device for Colorectal Endoscopic Submucosal Dissection

Background/Aims

: Appropriate tissue tension and clear visibility of the dissection area using traction are essential for effective and safe endoscopic submucosal dissection (ESD). In this study, we developed a retractable robot-assisted traction device and evaluated its performance in colorectal ESD.

Methods

: An experienced endoscopist performed ESD 18 times on an ex vivo porcine colon using the robot and 18 times using the conventional method. The outcome measures were procedure time, dissection speed, procedure-related adverse events, and blind dissection rate.

Results

: Thirty-six colonic lesions were resected from ex vivo porcine colon samples. The total procedure time was significantly shorter in robot-assisted ESD (RESD) than in conventional ESD (CESD) (20.1±4.1 minutes vs 34.3±8.3 minutes, p<0.05). The submucosal dissection speed was significantly faster in the RESD group than in the CESD group (36.8±9.2 mm2/min vs 18.1±4.7 mm2/min, p<0.05). The blind dissection rate was also significantly lower in the RESD group (12.8%±3.4% vs 35.1%±3.9%, p<0.05). In an in vivo porcine feasibility study, the robotic device was attached to a colonoscope and successfully inserted into the proximal colon without damaging the colonic wall, and ESD was successfully performed.

Conclusions

: The dissection speed and safety profile improved significantly with the retractable RESD. Thus, our robotic device has the potential to provide simple, effective, and safe multidirectional traction during colonic ESD.

A study of traction endoscopic submucosal dissection using a unique traction device with a ring and a clip with an obtuse tip

Appropriate use of traction devices is important in Endoscopic Submucosal Dissection (ESD). The Sure-Clip Traction Band (Microtec: "traction band") is a disposable clip with a series of three small silicone rings, which can be used as a traction device by inserting the clip through two holes. The SB clip long with a 125-degree tip claw angle (SB Kawasumi: hereafter referred to as SB clip) has an obtuse angle tip, can be re-gripped and is considered to cause less damage to the digestive tract wall when withdrawn after clipping. We performed traction ESD using a traction band and SB clip. These were used for gastric ESD in 4 cases and colorectal ESD in 3 cases.

Development of a novel multipoint traction device for gastric and colorectal endoscopic submucosal dissection and evaluation of its efficacy and safety

BACKGROUND

Proper traction allows safer and easier endoscopic submucosal dissection; however, single-point traction may not be sufficient. In this study we assessed the safety, efficacy, and feasibility of our newly developed multipoint traction device.

METHODS

During an ex vivo study using a Konjac training model, two experts and two trainees resected 80 mock lesions of 20-mm diameter by performing endoscopic submucosal dissection with and without multipoint traction. The primary outcome was the success rate of the procedure involving traction. The secondary outcomes were the submucosal dissection time, dissection speed, and perforation during endoscopic submucosal dissection. During the in vivo study, to clarify the initial clinical outcomes, we used data from the electronic medical record of patients at our institution who underwent gastric and colorectal endoscopic submucosal dissection, which was performed by experts with our newly developed multipoint traction device, from March to December 2022.

RESULTS

The ex vivo study indicated that all traction procedures were successful. Higher resection speeds were observed with endoscopic submucosal dissection with traction than without traction (P < 0.001). Perforations were not observed. During the first in vivo clinical study, traction was feasible during 20 gastric and colorectal endoscopic submucosal dissection procedures. No adverse events occurred.

CONCLUSIONS

Our multitraction device can increase the submucosal dissection speed and simplify endoscopic submucosal dissection techniques, thus safely reducing technical challenges. The application of this device for endoscopic submucosal dissection could lead to safer and more efficient procedures. Clinical registration UMIN Clinical Trials Registry, Japan (registration number UMIN000053384).

The efficacy and safety of snare traction-assisted endoscopic submucosal dissection for circumferential superficial esophageal cancer

OBJECTIVE

This study aims to investigate the efficacy and safety of snare traction-assisted endoscopic submucosal dissection (ESD) for the management of circumferential superficial esophageal cancer.

METHODS

A total of 68 patients who underwent ESD for circumferential superficial esophageal cancer were included in this study. All the patients were divided into two groups based on whether the snare traction was used or not; the snare traction group (S-ESD, group n = 35) and the control group (C-ESD, group n = 33).

RESULTS

There was no significant difference in the size of the resected area between the groups [21.98 (18.30, 27.00) cm2 vs 24.00 (15.28, 30.72) cm2, P = 0.976]. The snare traction group had a shorter dissection time [92.00 (74.00, 121.00) min vs 110.00 (92.50, 137.00) min, P = 0.017] and a faster resection speed [0.28 ± 0.13 cm2/min vs 0.22 ± 0.11cm2/min, P = 0.040] compared to the control group. There were no statistically significant differences between the two groups in terms of hospital stay, cost, en bloc resection rate, R0 resection rate, curative resection rate, bleeding rate, perforation rate, stricture rate, and recurrence rate (P > 0.05).

CONCLUSION

Snare traction-assisted ESD is a safe and efficient approach for the treatment of circumferential superficial esophageal cancer. Its advantages includes shorter procedure so the anesthesia requirement, clear operative filed view, improved mucosal dissection efficiency, simple, and easily accessible equipment.

Efficacy, safety, and advantages of magnetic anchor-guided endoscopic submucosal dissection vs conventional endoscopic submucosal dissection: A retrospective paired cohort study

BACKGROUND

Endoscopic submucosal dissection (ESD) has been recommended as the first-line treatment for early gastric cancer (EGC). However, poor visualization of the operative field increases both the procedure time and the risk of complications, especially for large and difficult lesions. We introduced a novel technique, magnetic anchor-guided ESD (MAG-ESD) and compared it with conventional ESD (C-ESD) for the treatment of large EGCs in terms of efficacy, safety, and advantages.

METHODS

Patients with large EGCs who underwent MAG-ESD or C-ESD at the First Affiliated Hospital of Xi'an Jiaotong University from March 2020 to March 2022 were retrospectively enrolled in this study. The patients in the MAG-ESD cohort were matched to those in the C-ESD cohort using propensity score-based matching. The operation time, submucosal dissection time, complete resection status, magnetic anchor, adverse event rate, and tumor recurrence rate were evaluated.

RESULTS

Twenty-two patients who underwent MAG-ESD were ultimately matched to those who underwent C-ESD. The median operation time of MAG-ESD and C-ESD was 43 minutes (IQR, 35.2-49.5) and 50.5 minutes (IQR, 42.0-76.0), respectively, among which the submucosal dissection time was 7.6 minutes (IQR, 5.2-10.4) and 14.8 minutes (IQR, 10.8-19.6), respectively. The operation time of MAG-ESD was shorter than that of C-ESD, especially the submucosal dissection time (P < .05). There was a lower incidence of adverse events associated with MAG-ESD (P < .05) when magnetic anchors were successfully placed and retrieved.

CONCLUSION

MAG-ESD is feasible, effective, safe, and simple for the treatment of large EGCs at different sites and has a high anchor success rate, which could shorten the operation time and reduce the adverse event rate.

Novel miniature transendoscopic telerobotic system for endoscopic submucosal dissection (with videos)

BACKGROUND AND AIMS

The lack of tissue traction and instrument dexterity to allow for adequate visualization and effective dissection were the main issues in performing endoscopic submucosal dissection (ESD). Robot-assisted systems may provide advantages. In this study we developed a novel transendoscopic telerobotic system and evaluated its performance in ESD.

METHODS

A miniature dual-arm robotic endoscopic assistant for minimally invasive surgery (DREAMS) was developed. The DREAMS system contained the current smallest robotic ESD instruments and was compatible with the commercially available dual-channel endoscope. After the system was established, a prospective randomized controlled study was conducted to validate the performance of the DREAMS-assisted ESD in terms of efficacy, safety, and workload by comparing it with the conventional technique.

RESULTS

Two robotic instruments can achieve safe collaboration and provide sufficient visualization and efficient dissection during ESD. Forty ESDs in the stomach and esophagus of 8 pigs were completed by DREAMS-assisted ESD or conventional ESD. Submucosal dissection time was comparable between the 2 techniques, but DREAMS-assisted ESD demonstrated a significantly lower muscular injury rate (15% vs 50%, P = .018) and workload scores (22.30 vs 32.45, P < .001). In the subgroup analysis of esophageal ESD, DREAMS-assisted ESD showed significantly improved submucosal dissection time (6.45 vs 16.37 minutes, P = .002), muscular injury rate (25% vs 87.5%, P = .041), and workload (21.13 vs 40.63, P = .001).

CONCLUSIONS

We developed a novel transendoscopic telerobotic system, named DREAMS. The safety profile and technical feasibility of ESD were significantly improved with the assistance of the DREAMS system, especially in the narrower esophageal lumen.

A novel miniature flexible robotic system for endoscopic mucosal dissection: an animal experimental study

Endoscopic submucosal dissection (ESD) is a standard treatment for early gastrointestinal cancer due to its higher rate of en-bloc resection and lower recurrence rate. However, the technical challenges lead to long learning curve and high risks of adverse events. A gastrointestinal flexible robotic-tool system (GIFTS) was proposed to reduce the difficulty and shorten the learning curve of novices. This is an animal study to evaluate the feasibility of GIFTS in ESD. The GIFTS provides a total of 13 degrees of freedom within 10 mm in diameter and variable stiffness function to achieve endoscopic intervention and submucosal dissection with the cooperation of two flexible robotic instruments. One esophageal and four colorectal ESDs in five porcine models were performed. In all five ESD procedures, the GIFTS was successfully intubated and submucosal dissection was completed without perforation or significant bleeding, and there was no system fault. The mean operative time was 99 min, and the mean size of the specimen was 151 mm2. The fifth experiment showed significantly better results than the first one. In vivo animal experiments confirmed the feasibility of GIFTS in performing ESD. The control of GIFTS is friendly to inexperienced beginners, which will help reduce the technical challenges of ESD and shorten the learning curve of endoscopists.

ESD with elastic ring traction is more effective and safer than conventional ESD in large proximal colon neoplastic lesions: a retrospective cohort study (with video)

BACKGROUND AND AIMS

Colorectal endoscopic submucosal resection (ESD), especially ESD in proximal colon, has always been challenging. We invented a novel elastic ring as a traction method to facilitate ESD. Our study aims to compare the safety and effectiveness of ESD with in vivo traction and conventional ESD without traction in the treatment of large proximal colon neoplastic lesions.

METHODS

This retrospective cohort study included consecutive patients with large (≥ 20 mm in their maximal diameter) proximal colon neoplastic lesions who underwent ESD with in vivo elastic ring traction or conventional ESD without traction in our endoscopy center between June 2018 and April 2022 by one experienced endoscopist.

RESULTS

The ESD with traction group has lower overall complication rate and lower perforation rate than those in the conventional ESD group (0% vs 14.71%, P = 0.021; 0% vs 11.76%, P = 0.048, respectively), and the differences are statistically significant. Although there are no significant differences in the rates of en bloc resection and R0 resection and bleeding rate, ESD with traction group still had higher en bloc resection and R0 resection rates and lower bleeding rate than conventional ESD group without traction (100% vs 94.12%, P = 0.226; 94.59% vs 85.29%, P = 0.189, 8.82% vs 2.70%, P = 0.276, respectively).

CONCLUSION

ESD with elastic ring traction is potentially more effective and safer than conventional ESD in the treatment of large proximal colon neoplastic lesions. Further large, prospective controlled studies are needed to fully evaluate this novel method.

Magnetic anchor technique assisted endoscopic submucosal dissection for early esophageal cancer

BACKGROUND

Esophageal cancer has high incidence globally and is often diagnosed at an advanced stage. With the widespread application of endoscopic technologies, the need for early detection and diagnosis of esophageal cancer has gradually been realized. Endoscopic submucosal dissection (ESD) has become the standard of care for managing early tumors of the esophagus, stomach, and colon. However, due to the steep learning curve, difficult operation, and technically demanding nature of the procedure, ESD has currently been committed to the development of various assistive technologies.

AIM

To explore the feasibility and applicability of magnetic anchor technique (MAT)-assisted ESD for early esophageal cancer.

METHODS

Isolated pig esophagi were used as the experimental model, and the magnetic anchor device was designed by us. The esophagi used were divided into two groups, namely the operational and control groups, and 10 endoscopists completed the procedure. The two groups were evaluated for the following aspects: The total operative time, perforation rate, rate of whole mucosal resection, diameter of the peering mucosa, and scores of endoscopists' feelings with the procedure, including the convenience, mucosal surface exposure degree, and tissue tension. In addition, in the operational group, the soft tissue clip and the target magnet (TM) were connected by a thin wire through a small hole at the tail end of the TM. Under gastroscopic guidance, the soft tissue clip was clamped to the edge of the lesioned mucosa, which was marked in advance. By changing the position of the anchor magnet (AM) outside the esophagus, the pulling force and pulling direction of the TM could be changed, thus exposing the mucosal peeling surface and assisting the ESD.

RESULTS

Herein, each of the two groups comprised 10 isolated esophageal putative mucosal lesions. The diameter of the peering mucosa did not significantly differ between the two groups (2.13 ± 0.06 vs 2.15 ± 0.06, P = 0.882). The total operative time was shorter in the operational group than in the control group (17.04 ± 0.22 min vs 21.94 ± 0.23 min, P < 0.001). During the entire experiment, the TM remained firmly connected with the soft tissue clip and did not affect the opening, closing, and release of the soft tissue clip. The interaction between the TM and AM could provide sufficient tissue tension and completely expose the mucosa, which greatly assists the surgeon with the operation. There was no avulsion of the mucosa, and mucosal lesions were intact when peeled. Therefore, the scores of endoscopists' feelings were higher in the operational group than in the control group in terms of the convenience (9.22 ± 0.19 vs 8.34 ± 0.15, P = 0.002), mucosal surface exposure degree (9.11 ± 0.15 vs 8.25 ± 0.12, P < 0.001), and tissue tension (9.35 ± 0.13 vs 8.02 ± 0.17, P < 0.001). The two groups did not significantly differ in the perforation rate and rate of whole mucosal resection.

CONCLUSION

We found MAT-assisted ESD safe and feasible for early esophageal cancer. It could greatly improve the endoscopic operation experience and showed good clinical application prospects.

Robot-assisted endoscopic submucosal dissection contributes to efficient and safe learning for novices: Prospective pilot cross-over ex vivo study (with video)

OBJECTIVES

The lack of effective countertraction to expose the submucosal layer contributes to the technical complication and adverse events in endoscopic submucosal dissection (ESD). We aimed to evaluate the efficacy and safety of a novel endoscopic robot (flexible auxiliary single-arm transluminal endoscopic robot [FASTER]) for ESD learning for novices.

METHODS

This was a prospective, cross-over designed pilot study in ex vivo porcine stomach. Four ESD novices were randomized to either FASTER-assisted ESD first (FC) group or a conventional ESD first (CF) group, performed 40 gastric ESDs using each technique, then crossed over to another technique. The performance and learning curve were compared between the two groups.

RESULTS

In the first phase, novices in the FC group demonstrated significantly better performance with shorter procedure time (25.6 ± 7.8 vs. 38.9 ± 13.4 min; P < 0.001) and submucosal dissection time (13.9 ± 5.5 vs. 23.1 ± 11.0 min; P < 0.001), higher direct-vision dissection ratio (84.0 ± 7.9% vs. 43.5 ± 20.7%; P < 0.001), and lower muscular injury (2.5 vs. 40.0%; P < 0.001) and task load (4 vs. 5; P < 0.001). Fewer ESDs were required to gain early proficiency in the FC group. When crossed to the second phase, procedure time in the FC group was prolonged but the muscular injury rate did not increase significantly. In total, endoscopists in the FC group tended to have a lower task load (4 vs. 5; P = 0.008) and less muscular injury (10.0 vs. 21.3%; P = 0.05).

CONCLUSION

Flexible auxiliary single-arm transluminal endoscopic robot-assisted learning reduces the technical difficulty of ESD for novices and the safety profile can sustain in following conventional ESD. These results indicated that FASTER has potential implications for ESD training in clinical practice.

Endoscopic surgery robot that facilitates insertion of the curved colon and ensures positional stability against external forces: K-COLON

BACKGROUND

Although various endoscopic surgery robots developed in previous studies are versatile and have high lesion accessibility, they have limitations in terms of reaching the target lesion through the curved path in the large intestine and providing a stable tasking environment for the operator.

METHODS

An endoscopic surgery robot was developed for performing surgery in the large intestine. The robot was easily inserted into the target lesion in the curved colon through the mounted soft actuator and demonstrated high structural stiffness through the insertion of the sigmoidal auxiliary tendons.

RESULTS

The robot was able to access the target lesion in the curved colon through teleoperation alone. Further, it was confirmed that the high structural stiffness overtube improved the overall task performance in the user test.

CONCLUSIONS

The proposed robotic system demonstrated the possibility and potential of performing advanced endoscopic surgery in the large intestine.

Robotic-assisted vs non-robotic traction techniques in endoscopic submucosal dissection for malignant gastrointestinal lesions

Endoscopic submucosal dissection is an effective approach with higher en bloc resection and complete resection rate for superficial gastrointestinal (GI) lesions. However, endoscopic submucosal dissection is technically challenging and associated with several adverse events, such as bleeding or perforations. The single channel flexible endoscope’s intrinsic limitations in preserving visualization of the submucosal dissection plane as compared to laparoscopic surgery are the most common cause of complications during the endoscopic submucosal dissection technique. As a result, traction techniques were created as the endoscope’s second helping hand in order to improve the effectiveness of the endoscopic submucosal dissection method. Trainees can master endoscopic submucosal dissection methods more quickly by using traction techniques. The anatomical location of the lesion plays a major role in determining which traction technique should be employed. An appealing way of traction is robot-assisted endoscopic submucosal dissection, and various types of endoscopic robots that allow bimanual operation are currently being developed. The advent of robot-assisted endoscopic technology ushers in a new era of endoscopic submucosal dissection, and with it come its own unique challenges that remain to be elucidated. Future research and development efforts are needed to focus on pathways and curriculums for trainees to master the currently available traction techniques and provide avenues for the development of newer traction modalities. In this article, we discuss evolution, characteristics, technological improvements and clinical comparisons of both robotic and non-robotic endoscopic traction techniques used in endoscopic submucosal dissection.

Simplified robot-assisted endoscopic submucosal dissection for esophageal and gastric lesions: a randomized controlled porcine study (with videos)

BACKGROUND AND AIMS

Effective countertraction is a main challenging issue in endoscopic submucosal dissection (ESD). Several countertraction methods have been developed to address this issue. The aim of this study was to compare the efficacy of ESD using a novel simplified robot, the flexible auxiliary single-arm transluminal endoscopic robot (FASTER), with a traditional technique.

METHODS

This was a prospective, randomized animal study. Forty-eight ESDs in 6 pigs were carried out at 8 different locations (gastric antrum, gastric body, lower esophagus, and middle esophagus) by the conventional method (n = 24) and by the FASTER-assisted method (n = 24). The primary outcomes were total procedure time, dissection time, and rate of direct-vision dissection. Secondary endpoints were completeness of en-bloc resection and adverse event rate.

RESULTS

The total procedure time was significantly shorter in FASTER-assisted ESD than in conventional ESD (18.8 vs 32.8 minutes; P < .001). In contrast to the median direct-vision dissection rate of 73% with conventional ESD, the FASTER-assisted group had a significantly higher rate of 96% (P < .001). The number of sites of muscular damage was significantly lower using the FASTER-assisted method than the conventional method (6 vs 21, respectively; P = .018). This improvement was more apparent in esophageal lesions compared with gastric lesions.

CONCLUSIONS

This study demonstrated that using a simplified robot during ESD is technically feasible and enables the endoscopist to dynamically use countertraction. This device could significantly reduce procedure time compared with conventional ESD techniques.

Sigmoidal Auxiliary Tendon-Driven Mechanism Reinforcing Structural Stiffness of Hyper-Redundant Manipulator for Endoscopic Surgery

The overtube of an endoscopic surgery robot is fixed when performing tasks, unlike those of commercial endoscopes, and this overtube should have high structural stiffness after reaching the target lesion so that sufficient tension can be applied to the lesion tissue with the surgical tool and there are fewer changes in the field of view of the endoscopic camera from this reaction force. Various methods have been proposed to reinforce the structural stiffnesses of hyper-redundant manipulators. However, the safety, rapid response, space efficiency, and cost-effectiveness of these methods should be considered for use in actual clinical environments, such as the gastrointestinal tract. This study proposed a method to minimize the positional changes of the overtube end tip due to external forces using only auxiliary tendons in the optimized path without additional mechanical structures. Overall, the proposed method involved moving the overtube to the target lesion through the main driving tendon and applying tension to the auxiliary tendons to reinforce the structural stiffness. The complete system was analyzed in terms of energy, and the sigmoidal auxiliary tendons were verified to effectively reinforce the structural stiffness of the overtube consisting of rolling joints. In addition, the design guidelines of the overtube for actual endoscopic surgery were proposed considering hollowness, retroflexion, and high structural stiffness. The positional changes due to external forces were confirmed to be reduced by 60% over the entire workspace.

Traction method versus conventional endoscopic submucosal dissection for gastric epithelial neoplasms: A randomized controlled trial

INTRODUCTION

Endoscopic submucosal dissection (ESD) is an advanced therapeutic technique for en bloc resection of superficial gastrointestinal neoplasms. Although gastric ESD is minimally invasive and provides favorable outcomes, it is technically difficult and requires a long procedure time for dissection. The traction-assisted approach overcomes some of the difficulties of gastric ESD, but its ability to reduce the procedure time remains unclear. The traction-assisted approach using dental floss and a clip did not reduce procedure time in the total population, but it reduced procedure time for lesions limited to the greater curvature of the upper or middle of the stomach. Although the traction direction of the clip-with-line method may be limited to the oral side via the cardia, EndoTrac ESD may provide flexible traction at any time during the procedure. This prospective randomized control study has been designed to compare the efficacy and safety of EndoTrac and conventional gastric ESD.

METHODS/DESIGN

This multicenter, randomized control trial will enroll 150 patients at 2 hospitals in Japan undergoing EndoTrac or conventional ESD for gastric epithelial neoplasia. Patients with a single gastric epithelial neoplasm who meet the inclusion and exclusion criteria will be randomized to EndoTrac or conventional ESD. Patients will be randomized by a computer-generated random sequence with stratification by operator experience, tumor size, tumor location, and institution. The primary endpoint will be ESD procedure time, defined as the time from the start of the submucosal injection to the completion of resection. Other outcomes will include the rates of adverse events and pathological curability.

DISCUSSION

The ability of EndoTrac ESD to reduce the long procedure time and/or adverse events observed with conventional ESD can not only reduce physical stress on the patient, but can also reduce length of hospital stay and medical costs. Reduced technical difficulty will contribute to the widespread adoption of this ESD technique worldwide.

TRIAL REGISTRATION

University Hospital Medial Information Network Clinical Trials Registry (UMIN-CTR), ID: 000044450; Registered on June 6, 2021.https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000050485.

PROTOCOL VERSION NUMBER

1.1, March 1, 2022. Patient enrolment began on June 6, 2021 and is expected to be completed by July 19, 2025.

A novel flexible auxiliary single-arm transluminal endoscopic robot facilitates endoscopic submucosal dissection of gastric lesions (with video)

BACKGROUND

Using conventional endoscope to perform endoscopic submucosal dissection (ESD) is difficult because of the one-handed operation and blind dissection caused by gravity. Poor visualization of the submucosal plane causes ESD to be associated with a high risk of bleeding and perforation. This study aimed to develop a novel ESD-assistive robot system and to evaluate its efficacy.

METHODS

A novel flexible auxiliary single-arm transluminal endoscopic robot (FASTER) was developed. A total of 36 artificial lesions in ex vivo porcine stomachs were removed using the FASTER-assisted ESD method (n = 18) and the conventional ESD method (n = 18). Lesions were 2 cm or 4 cm in diameter, located on the anterior and posterior walls of the antrum. Primary outcome measurements were dissection time and dissection speed.

RESULTS

The dissection time in FASTER-assisted ESD was significantly shorter than that in conventional ESD (7 min vs 13 min, p = 0.012), mainly because of the faster dissection speed (148.6 vs 97.0 mm²/min, p = 0.002). The total procedure time in FASTER-assisted ESD was shorter than that in conventional ESD, but the difference was not significant (16 min vs 24 min, p = 0.252). Complete en bloc resection was achieved in all lesions. No perforations were detected. The FASTER exhibited the ability of regrasp, multidirectional traction, and proper tension control during ESD.

CONCLUSION

FASTER significantly increased the dissection speed by providing proper traction and achieving good submucosal vision. This new device is expected to facilitate ESD in clinical practice.

Stress Dispersion Design in Continuum Compliant Structure toward Multi-DOF Endoluminal Forceps

Gastrointestinal cancer, when detected early, is treated by accessing the lesion through the natural orifice using flexible endoscopes. However, the limited degree-of-freedom (DOF) of conventional treatment devices and the narrow surgical view through the endoscope demand advanced techniques. In contrast, multi-DOF forceps systems are an excellent alternative; however, these systems often involve high fabrication costs because they require a large number of micro-parts. To solve this problem, we designed compact multi-DOF endoluminal forceps with a monolithic structure comprising compliant hinges. To allow an efficient stress dispersion at the base end when the hinge bends, we proposed a novel design method to obtain the hinge parameters using the beam of uniform strength theory. This method does not involve a high computational cost. The results show that the improved design with a variable hinge thickness can reduce the maximum bending stress, dispersing the stress in a larger area than that of the previous design considering a constant thickness of the hinge. Moreover, the experiments conducted in a prototype confirm that the radius of the curvature was significantly improved. The proposed method could aid in designing other continuum robots relying on compliant hinges.

Initial clinical experience with a novel flexible endoscopic robot for transanal surgery

Background

The Flex^® Robotic System (Medrobotics, Raynham, MA, USA) is the first miniaturised flexible endoscopic robot that aims to allow surgical manoeuvres beyond the area currently reached by transanal endoscopic microsurgery. The aim of this study is to evaluate our initial clinical experience with this novel tool.

Methods

We prospectively collected all consecutive cases of local excisions of rectal lesions performed with the Flex^® Robotic System performed at the Department of Surgical Sciences of the University of Turin between October 2018 and December 2019. Indications were benign, or early rectal lesions judged unsuitable for endoscopic removal, within 20 cm of the anal verge. Debriefing meetings after each procedure allowed technology assessment leading to the modification, development, and implementation of tools according to the clinical experience. We analysed the data in terms of the safety and efficacy of treatment.

Results

Between October 2018 and February 2020, 26 patients were treated. We performed a full-thickness excision in 14 patients and a submucosal dissection in 12. The median operating time was 115 min (range 45–360 min). In six patients (23.1%), we converted to standard transanal endoscopic operation (TEO^®) (Karl Storz, Tuttlingen, Germany) to complete the procedure. The 30-day morbidity rate was 11.5% (3/26). Positive resection margins were detected in 4 (15.4%) patients. At a minimum follow-up of 12 months, 2 (7.7%) local recurrences were observed.

Conclusions

This first clinical series demonstrates that the Flex^® Robotic System is a fascinating technology that deserves further development to increase surgical dexterity, thereby overcoming current technical limitations and improving clinical outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10151-022-02577-1.

Surgical Robot for Intraluminal Access: An Ex Vivo Feasibility Study

Early-stage gastrointestinal cancer is often treated by endoscopic submucosal dissection (ESD) using a flexible endoscope. Compared with conventional percutaneous surgery, ESD is much less invasive and provides a high quality of life for the patient because it does not require a skin incision, and the organ is preserved. However, the operator must be highly skilled because ESD requires using a flexible endoscope with energy devices, which have limited degrees of freedom. To facilitate easier manipulation of these flexible devices, we developed a surgical robot comprising a flexible endoscope and two articulating instruments. The robotic system is based on a conventional flexible endoscope, and an extrapolated motor unit moves the endoscope in all its degrees of freedom. The instruments are thin enough to allow insertion of two instruments into the endoscope channel, and each instrument has a bending section that allows for up–down, right–left, and forward–backward motion. In this study, we performed an ex vivo feasibility evaluation using the proposed robotic system for ESD in a porcine stomach. The procedure was successfully performed by five novice operators without complications. Our findings demonstrated the feasibility of the proposed robotic system and, furthermore, suggest that even operators with limited experience can use this system to perform ESD.

Robotic endoscopic submucosal dissection and full-thickness excision for laterally spreading tumors of the rectum

Endoscopic submucosal dissection (ESD) is technically demanding and time-consuming. Moreover, it bears a high risk of adverse events compared to other endoscopic methods, due to the lack of tissue manipulation. Robotic technology can significantly reduce the time of the procedure and increase the rate of complete resection for ESD. In the case of an unclear deep margin it allows to proceed to the full-thickness excision of the bowel wall. While the gain over transanal endoscopic microsurgery (TEM) is limited today, the longer systems currently under development will allow these complex procedures to be performed at least in the left side of the colon. The Supplementary video shows the application of the Flex Robotic System to perform an ESD and a full-thickness excision.

Usefulness of tumor traction with a snare and endoclips in gastric submucosal tumor resection: a propensity-score-matching analysis

Background

Endoscopic resection, including endoscopic submucosal dissection (ESD) and endoscopic full-thickness resection (EFR), was used to resect small gastric submucosal tumors (SMTs). Our team explored a method of tumor traction using a snare combined with endoclips to assist in the resection of SMTs. This study aims to explore the safety and effectiveness of the method.

Methods

This research performed a propensity-score-matching (PSM) analysis to compare ESD/EFR assisted by a snare combined with endoclips (ESD/EFR with snare traction) with conventional ESD/EFR for the resection of gastric SMTs. Comparisons were made between the two groups, including operative time, en bloc resection rate, perioperative complications, and operation-related costs.

Results

A total of 253 patients with gastric SMTs resected between January 2012 and March 2019 were included in this study. PSM yielded 51 matched pairs. No significant differences were identified between the two groups in perioperative complications or the costs of disposable endoscopic surgical accessories. However, the ESD/EFR-with-snare-traction group had a shorter median operative time (39 vs 60 min, P = 0.005) and lower rate of en bloc resection (88.2% vs 100%, P = 0.027).

Conclusions

ESD/EFR with snare traction demonstrated a higher efficiency and en bloc resection rate for gastric SMTs, with no increases in perioperative complications and the costs of endoscopic surgical accessories. Therefore, the method seems an appropriate choice for the resection of gastric SMTs.

A Novel Snare Traction-Assisted Method During Endoscopic Resection for Upper Gastrointestinal Submucosal Tumors

Background: Traction-assisted endoscopic resection is an approach to provide better procedural outcomes than conventional endoscopic procedure in treating gastric or esophageal epithelial lesions. Submucosal tumors (SMTs) are challenging to resect endoscopically due to the difficulty in exposure and high incidence of full-thickness resection. In this study, we investigated the efficacy of snare traction-assisted method, served as an "extra hand," for upper gastrointestinal SMTs. Methods: From June 2019 to May 2020, we used the snare traction-assisted method to treat 11 patients with 12 upper gastrointestinal SMTs in the Sixth Affiliated Hospital, Sun Yat-sen University. The duration of the procedures and the outcomes were recorded. Results: A total of 11 patients with 12 lesions were treated by snare traction-assisted endoscopic resection. The mean procedure time was 26.8 ± 8.3 minutes. En bloc resection was achieved in all the 12 lesions. The mean length of the specimens was 11.5 ± 4.0 mm. Full-thickness resection was performed in four lesions. The patients were discharged in 5.0 days after procedures without delayed bleeding or other complication reported. Conclusion: Snare traction-assisted method is an effective tool for endoscopic resection of upper gastrointestinal SMTs. Further prospective studies comparing the snare traction-assisted method with the conventional procedure are necessary.

Usefulness of the flexible traction method in gastric endoscopic submucosal dissection: an in-vivo animal study

BACKGROUND

An appropriate traction of the target lesion is a key for a safe and secure ESD procedure. We proposed the flexible traction method (F-trac) which provided an optimal traction using an endoscopic hand-suturing (EHS) and investigated the usefulness of this technique for gastric ESD in-vivo porcine model.

METHODS

In the F-trac method, a lesion was suspended by pulling proximal side of endoscope which was connected to the contralateral side with a barbed suture using the EHS technique just before starting the submucosal dissection. A single endoscopist performed conventional ESD (C-ESD) and F-trac ESD alternately for a total of ten simulating lesions of 3 cm in diameter in a live porcine stomach. The pig was rotated so that each lesion was positioned in the direction of the gravity. The procedure time, technical accuracy, adverse events, and the number of additional injection to the submucosal layer during dissection were evaluated.

RESULTS

The total ESD procedure time in the F-trac group was significantly shorter than in C-ESD group (19.0 min vs. 30.6 min, p = 0.039). There were no significant differences between both groups in muscular layer damage, sample damage, perforation, and intraoperative bleeding. The number of additional injection in the F-trac group was significantly fewer than that in C-ESD group (0 times vs. 4.4 times, p = 0.027).

CONCLUSIONS

In gastric ESD, F-trac might be useful for shortening the total procedure time. This method can facilitate optimal traction without disturbing the endoscopic visualization and the movement of endoscope.

Comparable Data Between Double Endoscopic Intraluminal Operation and Conventional Endoscopic Submucosal Dissection for Esophageal Cancer

BACKGROUND

Endoscopic submucosal dissection (ESD) of superficial esophageal cancer has been used increasingly as an alternative to surgery because it is minimally invasive and has a high rate of en bloc resection. We previously reported that the double endoscopic intraluminal operation (DEILO) is a useful technique for ESD of early esophageal cancers. In the current study, we showed comparable short-term data between DEILO and conventional ESD groups to demonstrate the further advanced use of DEILO.

METHODS

We studied 111 esophageal cancer patients with 111 lesions treated using endoscopic surgery between January 2010 and June 2016 at Gunma University Hospital. Of the patients, 51 underwent DEILO (DEILO group) and 60 underwent conventional ESD (ESD group). We compared the operable performance, complications, and pathological outcome between the ESD and DEILO groups.

RESULTS

There was no significant difference in operable performance. However, the DEILO group showed a significantly lower rate of mediastinal emphysema compared to the ESD group (p = 0.025). Overall, the DEILO group showed a lower complication rate compared to the ESD group, although there was no apparent significance.

CONCLUSION

To our knowledge, this is the first report comparing DEILO and conventional ESD for esophageal cancer. The results showed that DEILO is not inferior to conventional ESD. DEILO is an excellent endoscopic surgical method, although it has some limitations compared to conventional ESD.

Conventional versus traction-assisted endoscopic submucosal dissection for large esophageal cancers: a multicenter, randomized controlled trial (with video)

BACKGROUND AND AIMS

Endoscopic submucosal dissection (ESD) is widely used as a minimally invasive treatment for large esophageal cancers, but prolonged procedure duration and life-threatening adverse events remain matters of concern. We aimed to determine whether traction-assisted ESD (TA-ESD) is superior to conventional ESD in terms of technical outcomes.

METHODS

A superiority, randomized, phase III trial was conducted at 7 institutions across Japan. Patients with large esophageal cancer (defined as tumor diameter >20 mm) were eligible for this study. Enrolled patients were randomly assigned to undergo conventional ESD or TA-ESD. The primary endpoint was ESD procedure duration.

RESULTS

Two hundred forty-one patients were recruited and randomized. On applying exclusion criteria, 117 and 116 patients who underwent conventional ESD and TA-ESD, respectively, were included in the baseline analysis. In 1 patient, conventional ESD was discontinued because of severe perforation. Thus, the final analysis included 116 patients per group (primary analysis). The ESD procedure duration was significantly shorter for TA-ESD than for conventional ESD (44.5 minutes vs 60.5 minutes, respectively; P < .001). Moreover, no adverse events were noted in the TA-ESD group. The rate of horizontal margin involvement did not differ between the groups (10.3% vs 6.9% for conventional ESD and TA-ESD, respectively; P = .484).

CONCLUSIONS

TA-ESD was superior to conventional ESD in terms of procedure duration and was not associated with any adverse events. TA-ESD should be considered the procedure of choice for large esophageal cancers. (Clinical trial registration number: UMIN000024080.).

Endoscopic submucosal dissection of distal intestinal tumors using grasping forceps for traction

BACKGROUND

The aim of this study was to assess the efficacy of traction device-assisted endoscopic submucosal dissection (ESD) of the rectum and the distal segment of sigmoid colon using grasping forceps.

METHODS

A total of 43 patients scheduled for colonic ESD at our institution were enrolled between January 2013 and June 2017. The patients were randomly allocated to receive conventional ESD (group A) or traction device-assisted ESD (group B). The procedure time, complication rate, and en-block resection rate in the two groups were compared.

RESULTS

A total of 41 patients completed the study. The procedure time, complication rate and en-block resection rate were, respectively, 104.1 ± 34.7 min, 15%, 90% in the routine group (group A) and 84.7 ± 23.5 min, 9.5%, 90.5% in traction device-assisted ESD (group B). The procedure time in group B was significantly less than that in group A (F = 4.442, p < 0.05).

CONCLUSIONS

Traction device-assisted ESD using grasping forceps is safe and effective in distal colon ESD.

Snare combined with endoscopic clips in endoscopic resection of gastric submucosal tumor: a method of tumor traction

Background and study aims  Mucosal traction as a supportive technique is very useful for endoscopists during endoscopy. For gastric submucosal tumor (SMT), our team explored a method of pulling the SMT with a snare combined with endoclips (PSMT-SE). This study preliminarily explored its feasibility to assist resection of gastric SMT. Patients and methods  Operation-related data from patients who underwent gastric SMT removal assisted by PSMT-SE at the Gastrointestinal Endoscopy Center of Guangzhou Nanfang Hospital, China between January 2017 and October 2018 were retrospectively collected: tumor size and location, origin of tumor, total operation time, en bloc resection rate, intraoperative and postoperative complications. Results  Forty-two gastric SMTs in 41 patients were included in this study. Fifteen tumors were located in the gastric fundus, 11 in the gastric body, two in the gastric angle, 10 in the gastric antrum, and four in the greater curvature of the gastric fundus and the body junction. Further, 11 tumors originated from the submucosa and 31 originated from the muscularis propria. Endoscopic submucosal dissection and endoscopic full-thickness resection assisted by PSMT-SE were performed to resect 30 and 12 tumors, respectively. PSMT-SE could effectively expose the surgical field. Median diameter of resected tumors was 2.0 (0.7) cm, the total operation time was 45.5 (27.0) min, and the en bloc resection rate was 100 %. No intraoperative or postoperative complications were observed. Conclusion  PSMT-SE is a potentially useful method for assisting resection of gastric SMT with tumor traction. Further prospective studies with large sample sizes are warranted.

Robot-assisted endoscopic submucosal dissection versus conventional ESD for colorectal lesions: outcomes of a randomized pilot study in endoscopists without prior ESD experience (with video)

BACKGROUND AND AIMS

Endoscopic submucosal dissection (ESD) is becoming the preferred method for certain early GI malignancies; however, very few U.S. physicians have adopted this technique. This is in part because of the technically challenging nature of the procedure and the long learning curve. Several endoscopic robots are under development to address these complexities.

METHODS

This is a randomized, controlled, pilot study comparing conventional ESD versus robotic-assisted ESD (RESD) in an ex vivo bovine colon model. Five endoscopists without prior ESD or RESD experience were randomized into 2 groups (group 1, RESD after ESD; group 2, RESD before ESD). A standard template was used to create colonic lesions. The primary outcome was completeness of en bloc resection. Secondary outcomes included differences in procedure time, perforation rate, muscle injury rate, and National Aeronautical and Space Administration Task Load Index (NASA-TLX) to assess physical and mental workload.

RESULTS

Five endoscopists each performed 4 tissue resections (2 RESD and 2 ESD), for a total of 20 procedures. Complete en bloc resection was achieved in all RESD and in 50% of ESD (P < .0001). The perforation rate was higher in the ESD group (60% vs 30%, P = .18). Total procedure time (34.1 vs 88.6 min, P = .001) and dissection time (27.8 vs 79.4 minutes, P = .002) were lower for RESD. The NASA-TLX also revealed better results for RESD (28.4 vs 47.4, P = .01).

CONCLUSIONS

RESD appears to be more effective in obtaining en bloc resection with shorter procedure times and a lower perforation rate compared with conventional ESD as performed by ESD novices. RESD is also associated with lower physical and mental workloads.

Snare combined with endoclips in endoscopic submucosal dissection with mucosal traction for gastroesophageal neoplasia

BACKGROUND AND AIM

Mucosal traction as a "second hand" in endoscopic submucosal dissection (ESD) is very helpful for ESD operators. The efficacy of using a snare combined with endoclips to assist in ESD (SC-ESD) was evaluated whether it could achieve peroral external traction (PET) and peroral internal traction (PIT) and real-time adjustment of mucosal traction position. This study aimed to preliminarily evaluate its feasibility.

METHODS

A snare was fixed using endoclips to the incised mucosal flap that was intended for dissection. Subsequently, the snare was adjusted to achieve mucosal traction. This study included 54 gastroesophageal neoplasias in 54 consecutive patients who underwent SC-ESD. The operative and clinical data were retrospectively collected.

RESULTS

Peroral external tractions were performed for 22 esophageal neoplasias, and PETs and PITs were performed for 32 gastric neoplasias. The median (interquartile range) sizes of lesions were 4.3 (2.5) and 4.2 (2.1) cm, operation times were 73.4 (43.8) and 60.0 (45.2) min, and submucosal dissection times were 27.0 (32.0) and 31.0 (34.5) min in the esophagus and stomach, respectively. Mucosal traction position could be effectively adjusted by fixing the snare to the incised mucosal flap intended for dissection during SC-ESD. All lesions in the esophagus and stomach were completely resected, with R0 resection rates of 100%. Besides postoperative bleeding in a patient with gastric neoplasia, no intraoperative and postoperative perforations occurred.

CONCLUSIONS

SC-ESD seems to be feasible for resecting gastroesophageal neoplasia, and two types of mucosal tractions (PET and PIT) could be effectively achieved during SC-ESD. Further prospective comparative study with a large sample is warranted.

Conventional versus traction-assisted endoscopic submucosal dissection for gastric neoplasms: a multicenter, randomized controlled trial (with video)

BACKGROUND AND AIMS

The aim of this study was to clarify whether dental floss clip (DFC) traction improves the technical outcomes of endoscopic submucosal dissection (ESD).

METHODS

A superiority, randomized control trial was conducted at 14 institutions across Japan. Patients with single gastric neoplasm meeting the indications of the Japanese guidelines for gastric treatment were enrolled and assigned to receive conventional ESD or DFC traction-assisted ESD (DFC-ESD). Randomization was performed according to a computer-generated random sequence with stratification by institution, tumor location, tumor size, and operator experience. The primary endpoint was ESD procedure time, defined as the time from the start of the submucosal injection to the end of the tumor removal procedure.

RESULTS

Between July 2015 and September 2016, 640 patients underwent randomization. Of these, 316 patients who underwent conventional ESD and 319 patients who underwent DFC-ESD were included in our analysis. The mean ESD procedure time was 60.7 and 58.1 minutes for conventional ESD and DFC-ESD, respectively (P = .45). Perforation was less frequent in the DFC-ESD group (2.2% vs .3%, P = .04). For lesions located in the greater curvature of the upper or middle stomach, the mean procedure time was significantly shorter in the DFC-ESD group (104.1 vs 57.2 minutes, P = .01).

CONCLUSIONS

Our findings suggest that DFC-ESD does not result in shorter procedure time in the overall patient population, but it can reduce the risk of perforation. When selectively applied to lesions located in the greater curvature of the upper or middle stomach, DFC-ESD provides a remarkable reduction in procedure time.

Usefulness of the S-O clip for gastric endoscopic submucosal dissection (with video)

BACKGROUND

Endoscopic submucosal dissection (ESD) is technically one of the most complicated endoscopic procedures. Traction methods have been reported to be effective for ESD. A recent study revealed that the S-O clip allowed faster and safer colonic ESD. We assessed the efficacy and safety of gastric ESD with the S-O clip for gastric epithelial neoplasm.

METHODS

We performed a retrospective cohort study of patients treated for gastric ESD using the S-O clip between September and November 2016 (SO group, n = 48). The subjects were matched with patients treated with conventional gastric ESD from September 2015 to August 2016 (control group, n = 258) at Sendai Kousei Hospital, a tertiary endoscopic center. The primary outcome was procedure time. Multivariate logistic regression and propensity score matching analyses were performed to reduce the effects of selection bias for potential confounding factors differences like age, sex, lesion location, lesion position, presence of ulcer scarring, resected specimen size, and operator experiences.

RESULTS

Forty-eight pairs were created after propensity score matching. The mean procedure time (including the S-O clip attachment time) was significantly shorter in the SO group (47.2 ± 24.6 vs. 69.2 ± 67.1 min, p = 0.035). The mean clip attachment time was 4.4 (range 2-15) min. There were no significant differences in other treatment outcomes (en-bloc resection rate: 100 vs. 100%, p = 1.000; perforation rate: 0 vs. 2.1%, p = 0.315; delayed bleeding rate: 2.1 vs. 4.3%, p = 0.558).

CONCLUSIONS

The S-O clip improved the speed of gastric ESD by approximately 25%, without increasing adverse events.

Magnetic anchor guidance for endoscopic submucosal dissection and other endoscopic procedures

Endoscopic submucosal dissection (ESD) is a well-established, minimally invasive treatment for superficial neoplasms of the gastrointestinal tract. The universal adoption of ESD has been limited by its slow learning curve, long procedure times, and high risk of complications. One technical challenge is the lack of a second hand that can provide traction, as in conventional surgery. Reliable tissue retraction that exposes the submucosal plane of dissection would allow for safer and more efficient dissection. Magnetic anchor guided endoscopic submucosal dissection (MAG-ESD) has potential benefits compared to other current traction methods. MAG-ESD offers dynamic tissue retraction independent of the endoscope mimicking a surgeon’s “second hand”. Two types of magnets can be used: electromagnets and permanent magnets. In this article we review the MAG-ESD technology, published work and studies of magnets in ESD. We also review the use of magnetic anchor guidance systems in natural orifice transluminal endoscopic surgery and the idea of magnetic non-contact retraction using surface ferromagentization. We discuss the current limitations, the future potential of MAG-ESD and the developments needed for adoption of this technology.

Usefulness of a traction method using dental floss and a hemoclip for gastric endoscopic submucosal dissection: a propensity score matching analysis (with videos)

BACKGROUND AND AIMS

Although endoscopic submucosal dissection (ESD) is a significant advancement in therapeutic endoscopy, it is a complicated technique and requires considerable expertise. In this exploratory study, we evaluated the efficacy of a simple traction method that uses dental floss and a hemoclip (DFC) and was developed to overcome the technical difficulties of ESD.

METHODS

In total, 238 early gastric cancers treated by ESD between May 2012 and December 2014 at Tokyo Medical University were retrospectively reviewed. Lesions treated by conventional ESD (n = 185) and by ESD with DFC (ESD-DFC) (n = 53) were compared. Multivariable analyses and propensity score matching were used to compensate for the differences in age, sex, resected specimen size, lesion location, lesion position, presence of ulceration, and operator level. The procedure time, rate of en bloc and complete resection, and rates of adverse events were evaluated between the 2 groups.

RESULTS

Propensity score matching analysis created 43 matched pairs. Adjusted comparisons between ESD-DFC and conventional ESD showed similar treatment outcomes (en bloc resection rate: 97.7% vs 100%, P = .315; complete resection rate: 90.7% vs 95.3%, P = .397; perforation during ESD rate: 2.3% vs 2.3%, P = 1.000; post-ESD bleeding rate: 4.7% vs 4.7%, P = 1.000) but a significantly shorter procedure time for ESD-DFC (82.2 ± 79.5 minutes vs 118.2 ± 71.6 minutes, P = .002).

CONCLUSION

ESD-DFC facilitated rapid ESD with good visualization and traction while ensuring high curability and safety.

Facilitating retroflexed endoscopic full-thickness resection through loop-mediated or rope-mediated countertraction (with videos)

BACKGROUND AND AIMS

Endoscopic full-thickness resection (EFTR) is difficult to perform in a retroflexed fashion in the gastric fundus and lesser curvature. Here we describe two simple methods to provide countertraction and thereby facilitate dissection.

METHODS

In this retrospective cohort study, 62 patients diagnosed as having gastric submucosal tumors in the fundus or in the lesser curvature received EFTR with or without countertraction methods. For the clip-with-thread method, a clip tied with surgical suture was anchored on the distal edge of the tumor to provide countertraction; for the loop-assisted method, a snare placed on the transparent cap beforehand was adopted to grasp the tumor to provide countertraction.

RESULTS

Mean operative time was significantly reduced in the thread-with-clip group and loop-assisted group (45 minutes, 40 minutes, respectively) compared with the time needed in the traditional EFTR group (85 minutes). Intraoperative pneumoperitoneum occurred regularly among the 3 groups because of iatrogenic perforation, but fewer patients in the thread-with-clip group and loop-assisted group (23%, 18%, respectively) needed abdominal puncture to relieve free air and stabilize life signs compared with patients in the traditional EFTR group (63%). A reduced occurrence of high fever after surgery may contribute as another advantage from accelerated dissection. Both techniques did not jeopardize oncologic safety during short-term follow-up.

CONCLUSIONS

Both the thread-with-clip method and loop-assisted method provide effective countertraction and offer faster and safer gastric EFTR in difficult anatomic locations.

ESD around the world: United States

Endoscopic submucosal dissection (ESD) is a well-established advanced mucosal resection technique used in Japan, where it originated, and some other Asian countries. The technical difficulty and potentially higher rates of significant complications have been obstacles for its dissemination across the United States, on top of the lack of available equipment, candidate lesions in the gastrointestinal tract, and adequate training programs. Yet American physicians are becoming increasingly aware of the benefits of ESD. Simplification of technique, modification of tools and materials, and improved availability of training opportunities are essential in order to accelerate the adoption of ESD in the United States.