Magnetic anchor guidance for endoscopic submucosal dissection and other endoscopic procedures

Clinical feasibility of laparoscopic left lateral segment liver resection with magnetic anchor technique: The first clinical study from China

BACKGROUND

Magnetic anchor technique (MAT) has been applied in laparoscopic cholecystectomy and laparoscopic appendectomy, but has not been reported in laparoscopic partial hepatectomy.

AIM

To evaluate the feasibility of the MAT in laparoscopic left lateral segment liver resection.

METHODS

Retrospective analysis was conducted on the clinical data of eight patients who underwent laparoscopic left lateral segment liver resection assisted by MAT in our department from July 2020 to November 2021. The Y-Z magnetic anchor devices (Y-Z MADs) was independently designed and developed by the author of this paper, which consists of the anchor magnet and magnetic grasping apparatus. Surgical time, intraoperative blood loss, intraoperative accidents, operator experience, postoperative incision pain score, postoperative complications, and other indicators were evaluated and analyzed.

RESULTS

All eight patients underwent a MAT-assisted laparoscopic left lateral segment liver resection, including three patients undertaking conventional 5-port and five patients having a transumbilical single-port operation. The mean operation time was 138 ± 34.32 min (range 95-185 min) and the mean intraoperative blood loss was 123 ± 88.60 mL (range 20-300 mL). No adverse events occurred during the operation. The Y-Z MADs showed good workability and maneuverability in both tissue and organ exposure. In particular, the operators did not experience either a "chopstick" or "sword-fight" effect in the single-port laparoscopic operation.

CONCLUSION

The results show that the MAT is safe and feasible for laparoscopic left lateral segment liver resection, especially, exhibits its unique abettance for transumbilical single-port laparoscopic left lateral segment liver resection.

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.

Magnetic ring-assisted endoscopic submucosal dissection for gastric lesions with submucosal fibrosis: A preliminary study in beagle model

BACKGROUND

During endoscopic submucosal dissection (ESD) for gastric lesions with fibrosis, appropriate traction could provide clear submucosal dissection visualization to improve safety and efficiency of procedures. Therefore, the aim of this study was to evaluate the feasibility of magnetic ring-assisted ESD (MRA-ESD) for gastric fibrotic lesions.

METHOD

In the eight healthy beagles, 2-3 mL of 50% glucose solution was injected into submucosal layer of the stomach to induce gastric fibrotic lesions. A week after submucosal injection, two endoscopists at different levels performed MRA-ESD or standard ESD (S-ESD) for gastric simulated lesions, respectively. The magnetic traction system consisted of external handheld magnet and internal magnetic ring. The feasibility and procedure outcomes of the magnetic traction system were mainly evaluated.

RESULTS

Forty-eight gastric simulated lesions with ulceration were confirmed to have submucosal fibrosis formation by preoperative endoscopic ultrasonography. The magnetic traction system could be easily established, only took 1.57 min, and allowed excellent submucosal visualization. The total procedure time was significantly shorter in the MRA-ESD group than in the S-ESD group for both endoscopists (mean: 46.83 vs. 25.09 min, p < 0.001), and this difference was accentuated in non-skilled endoscopist. There was significant difference between two groups in bleeding and perforation rates. Histological analysis showed the depth of resected specimens was a little deeper around the fibrotic portion in the S-ESD group (p < 0.001).

CONCLUSION

The magnetic ring-assisted ESD technique may be an effective and safe treatment for gastric fibrotic lesions and may shorten the endoscopic learning curve for non-skilled endoscopists.

First pilot trial of colorectal ESD guided by a new magnetic anchor for ease of placement

BACKGROUND

In recent years, studies have demonstrated that magnetic anchor-guided endoscopic submucosal dissection (MAG-ESD) is feasible and safe and may facilitate the treatment of all difficult lesions. However, the major problem with MAG-ESD is the inability to deliver the magnetic anchor to the gastrointestinal tract without withdrawal or reinsertion of the endoscope. Therefore, our team developed a magnetic anchor that could be easily inserted through the biopsy channel, facilitating ESD traction and evaluated its effectiveness and safety.

METHODS

The study was conducted between October 2020 and June 2021 at The Second Affiliated Hospital of Harbin Medical University, China. One hundred and twelve patients with colorectal tumors treated with ESD were divided into two groups for historical control comparison. A channel-placed magnetic anchor (CPMAG) group and a control group consisting of patients who had conventional ESD without adjuvant traction. The rate of en bloc resection and resection with tumor-free lateral/basal margins (R0 resection), dissection speeds, procedure time, intraoperative bleeding and perforation complications, and postoperative follow-up were compared between the two groups, so as to evaluate the clinical effect and safety of the new magnetic anchor.

RESULTS

The en bloc resection and R0 resection rate with CPMAG-ESD were slightly higher than with conventional ESD but this was not statistically significant. The median dissection speeds with CPMAG-ESD were higher than with conventional ESD, but the difference was not statistically significant. Intraoperative bleeding and postoperative complications with the CPMAG-ESD were less than with conventional ESD, but this was not statistically significant. The median operating time was shorter with CPMAG- ESD than with conventional ESD (24.5 min [range 15.8-66.5 min] vs 39 min [range 29-58 min], p = 0.024), and this difference was statistically significant.

CONCLUSIONS

The new magnetic anchor-guided ESD technique appears to be a feasible and safe method for treating early colorectal tumors with en bloc resection, with improvement of the submucosal visual field, and less adverse events.

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.

Training in Endoscopic Submucosal Dissection in the United States: The Current Paradigm

Endoscopic submucosal dissection (ESD) training in Japan is pursued through a designated master-apprentice, organ-based stepwise training model. However, applying a similar program to the United States is not a practical strategy due to the significant differences in the training system and disease prevalence. To incorporate the ESD training into the current advanced endoscopy fellowship program, the use of recently developed techniques and technologies to improve the efficiency of ESD is ideal. The ESD training program in the United States should be prevalence-based, with increased involvement of trainees depending on their objectively assessed competency levels.

The efficient of application of a fine magnetic traction system simplifies colorectal endoscopic submucosal dissection: A porcine study

BACKGROUND

Sometimes it is difficult to maintain good visualization of the submucosal layer during colorectal endoscopic submucosal dissection (ESD). This study aimed to evaluate the feasibility and efficacy of a novel traction method, the fine magnetic traction system (FMTS), in colorectal ESD.

METHODS

ESD was performed 10, 15, or 30 cm from the anus in the colorectums of 10 Bama miniature pigs with or without FMTS. The circumcision and dissection per unit time (cm²/min), en bloc resection, perforation and bleeding rates, size and integrity of the specimen and submucosal injection times were analysed.

RESULTS

A total of 60 ESD procedures were performed with or without FMTS assistance. The en bloc resection rates were 100% at 10 and 15 cm from the anus in both the control group (conventional ESD) and the FMTS group. However, at 30 cm from the anus, these rates were only 10% and 70% (p = 0.006). The resection speeds (control vs. FMTS) at the 10, 15, and 30 cm points were 0.35 ± 0.07 cm²/min vs. 0.39 ± 0.19 cm²/min (p = 0.56), 0.30 ± 0.09 cm²/min vs. 0.38 ± 0.02 cm²/min (p = 0.04), and 0.11 cm²/min vs. 0.26 ± 0.10 cm²/min, respectively.

CONCLUSIONS

The FMTS provides effective counter-traction and efficiently reduces the risks and difficulties of difficult colonic ESD in the porcine model.

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.

Deployable Tubular Mechanisms Integrated with Magnetic Anchoring and Guidance System

Deployable mechanism has received more attention in the medical field due to its simple structure, dexterity, and flexibility. Meanwhile, the advantages of the Magnetic Anchoring and Guidance System (MAGS) are further highlighted by the fact that the operators can remotely control the corresponding active and passive magnetic parts in vivo. Additionally, MAGS allows the untethered manipulation of intracorporeal devices. However, the conventional instruments in MAGS are normally rigid, compact, and less flexible. Therefore, to solve this problem, four novel deployable tubular mechanisms, Design 1 (Omega-shape mechanism), Design 2 (Fulcrum-shape mechanism), Design 3 (Archway-shape mechanism), and Design 4 (Scissor-shape mechanism) in this paper, are proposed integrated with MAGS to realize the laser steering capability. Firstly, this paper introduces the motion mechanism of the four designs and analyzes the motion characterization of each structure through simulation studies. Further, the prototypes of four designs are fabricated using tubular structures with embedded magnets. The actuation success rate, the workspace characterization, the force generation and the load capability of four mechanisms are tested and analyzed based on experiments. Then, the demonstration of direct laser steering via macro setup shows that the four mechanisms can realize the laser steering capability within the error of 0.6 cm. Finally, the feasibility of indirect laser steering via a macro-mini setup is proven. Therefore, such exploration demonstrates that the application of the deployable tubular mechanisms integrated with MAGS towards in vivo treatment is promising.

Orthodontic Rubber Band-Assisted Endoscopic Submucosal Dissection: An Efficient Method for Treating Superficial Colorectal Tumors

Background

Colorectal endoscopic submucosal dissection (ESD) is a complex operation. Effective traction is crucial. We have successfully used an orthodontic rubber band (ORB) combined with the clip traction method to assist ESD (ORB-ESD). The aim of this retrospective study is to describe the method and to compare the efficacy and safety of ORB-ESD versus conventional ESD in the treatment of superficial colorectal tumors.

Methods

We retrospectively analyzed the data of patients with superficial colorectal tumor (with diameter ≥ 20 mm) who received either ORB-ESD (n = 34) or conventional ESD (n = 90) between January 2019 and September 2020. Propensity score matching (PSM) was used to match the clinical data of 31 pairs of patients in each group.

Results

Operation time was significantly shorter for ORB-ESD than for conventional ESD (34.5 minutes vs. 56 minutes, P ≤ 0.001). In the propensity-matched cohorts, the operation time remained significantly shorter in the ORB-ESD patients (35 minutes vs. 50 minutes, P = 0.001). Postoperative adverse events, en bloc resection rate, and R0 resection rate were comparable between the two groups (P > 0.05), both before and after propensity score matching. In the ORB subgroup analysis, the trainee and expert ESD operation times were similar (37 (26–53) vs. 33.5 (26–37) minutes, respectively; P = 0.274).

Conclusion

ORB-ESD appears to be an effective technique for ESD of colorectal cancer. Our findings need to be confirmed in large prospective multicenter studies.

Endoscopic Management of Complex Colorectal Polyps: Current Insights and Future Trends

Most colorectal cancers arise from adenomatous polyps and sessile serrated lesions. Screening colonoscopy and therapeutic polypectomy can potentially reduce colorectal cancer burden by early detection and removal of these polyps, thus decreasing colorectal cancer incidence and mortality. Most endoscopists are skilled in detecting and removing the vast majority of polyps endoscopically during a routine colonoscopy. Polyps can be considered “complex” based on size, location, morphology, underlying scar tissue, which are not amenable to removal by conventional endoscopic polypectomy techniques. They are technically more challenging to resect and carry an increased risk of complications. Most of these polyps were used to be managed by surgical intervention in the past. Rapid advancement in endoscopic resection techniques has led to a decreasing role of surgery in managing these complex polyps. These endoscopic resection techniques do require an expert in the field and advanced equipment to perform the procedure. In this review, we discuss various advanced endoscopic techniques for the management of complex polyps.

Endoscopic diagnosis and treatment of gastric dysplasia and early cancer: Current evidence and what the future may hold

Gastric cancer accounts for a significant proportion of worldwide cancer-related morbidity and mortality. The well documented precancerous cascade provides an opportunity for clinicians to detect and treat gastric cancers at an endoscopically curable stage. In high prevalence regions such as Japan and Korea, this has led to the implementation of population screening programs. However, guidelines remain ambiguous in lower prevalence regions. In recent years, there have been many advances in the endoscopic diagnosis and treatment of early gastric cancer and precancerous lesions. More advanced endoscopic imaging has led to improved detection and characterization of gastric lesions as well as superior accuracy for delineation of margins prior to resection. In addition, promising early data on artificial intelligence in gastroscopy suggests a future role for this technology in maximizing the yield of advanced endoscopic imaging. Data on endoscopic resection (ER) are particularly robust in Japan and Korea, with high rates of curative ER and markedly reduced procedural morbidity. However, there is a shortage of data in other regions to support the applicability of protocols from these high prevalence countries. Future advances in endoscopic therapeutics will likely lead to further expansion of the current indications for ER, as both technology and proceduralist expertise continue to grow.

Magnetic anchoring and guidance-assisted endoscopic irreversible electroporation for gastric mucosal ablation: a preclinical study in canine model

BACKGROUND

The aim of this study was to evaluate the feasibility, safety, and efficacy of magnetic anchoring and guidance-assisted endoscopic irreversible electroporation (MAG-IRE) for gastric mucosal ablation.

METHODS

A catheter-based, donut-like, and MAG-assisted electrode was developed. MAG-IRE for gastric mucosal ablation was performed in eight beagle canines. The parameters of one set of IRE was 500 V voltage, 100 μs pulse duration, and 99 pulses. The MAG time, operation time, success rate, and adverse events were measured. Endoscopic examination was performed from 30 min to 28 days post-IRE. Full-thickness gastric tissue was harvested by wedge biopsy for histopathological analysis.

RESULTS

30 (93.75%) of the 32 lesions were successfully ablated by MAG-IRE. The median MAG time was 300 s (IQR 120-422.5 s), and the median operation time was 491.5 s (IQR 358.3-632.5 s). No adverse events occurred. Ulceration was observed, starting from 3 days post-IRE. The mucosa healed 14 to 28 days post-IRE. Hematoxylin-Eosin (H&E) staining showed inflammatory infiltration, edema, and congestion in the ablated mucosa. Masson's Trichrome staining showed that the gastric wall and blood vessels in the ablation area were intact. TUNEL assay showed diffuse positive cells in ablated mucosa as early as 30 min post-IRE.

CONCLUSIONS

MAG-IRE for gastric mucosal ablation is feasible, safe, and effective. It can be a potential therapeutic option for minimally invasive treatment of gastric neoplasm.

ESD and Pit Pattern Diagnosis: Lessons from a Japanese Endoscopist Working in the United States

Endoscopic submucosal dissection (ESD) was developed in 2000s to overcome the limitations of endoscopic mucosal resection (EMR), especially to accomplish en-bloc resection, and it has been accepted worldwide in the past decades. Many ESD devices and diagnosis modalities are currently available, which include pit pattern and narrow band imaging (NBI) diagnoses to evaluate the depth of the tumor preoperatively with sensitivities of 70 to 90%. Depending on the Japanese colorectal guideline, the intramucosal cancer and shallow invasion of the submucosal layer are the main good indications of ESD; however, the ESD practices between Japan and Western countries still vary, including pathologic definition of cancer, tumor/node/metastasis classification, and handling of ESD specimen. In the United States, despite the large demand for treatment of colorectal neoplasm, pit pattern and magnified NBI diagnoses are not widely accepted yet, and piecemeal EMR is still the major method in most of the institutions. Moreover, the specific guideline of ESD is also not available yet. More new technologies are being developed other than conventional ESD methods in Eastern and Western countries, and ESD is now expected to change in the next generation. It is recommended that not only gastroenterologists but also colorectal surgeons have appropriate knowledge of colorectal lesions and their management to ensure current treatments is applied to patients.

Current state of education and training for endoscopic submucosal dissection: Translating strategy and success to the USA

Endoscopic submucosal dissection (ESD) is a rigorous and technically sophisticated method for removal of lesions within the gastrointestinal tract. Despite having advantages of en-bloc resection of lesions, regardless of size, and widespread use in Japan and Asia, ESD has not become widely adopted in the USA for a variety of reasons. Based upon Japanese education and the master-apprentice model, modification to the education system and additional techniques designed to facilitate broader adoption are required for trainees in the USA. This article will review the current state of education and training for ESD in the USA.

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.

Methods that Assist Traction during Endoscopic Submucosal Dissection of Superficial Gastrointestinal Cancers: A Systematic Literature Review

Endoscopic submucosal dissection (ESD) is a well-established method for the treatment of early-stage gastrointestinal neoplasms. Adequate submucosal exposure is one of the most significant factors related to an effective and safe dissection. The aim of this systematic review was to evaluate the effcacy and safety of various methods that assist traction during ESD of precancerous and earlystage neoplastic lesions of the gastrointestinal tract. We performed an electronic search of the MEDLINE and the Cochrane Controlled Trials Register databases for relevant studies published up to May 2019. Trials exclusively recruiting patients undergoing ESD for superficial gastrointestinal cancer were considered eligible for inclusion. Thirty-three articles including 3,134 patients met the inclusion criteria. The studies evaluated different approaches for widening the endoscopic view, including magnetic anchor-guided ESD (3 studies), use of a second endoscope (5 studies), clip-involving technique (21 studies), and miscellaneous methods (4 studies). Among them, only 6 were randomized controlled trials evaluating different approaches. Overall, the implementation of methods that assist traction during ESD significantly improved the operating time and R0 resection rate and decreased the rate of complications (bleeding and perforation). Interventions that assist traction seem effcacious in improving tissue traction, thus facilitating ESD performance.

Endoscopic submucosal dissection: an update on tools and accessories

Endoscopic submucosal dissection (ESD) is a minimally invasive therapeutic procedure to remove larger polyps or early non-metastatic lesions. It has long been used in Asia, but is now fast growing in popularity in the West. There are multiple challenges faced by ESD practitioners. While the practice of ESD in gastric lesions is relatively well established, the oesophagus with its narrow lumen and challenging workspace, and the colon with its tortuous course and folds are more challenging frontiers. The nature of performing a procedure endoscopically means that conventional methods offer no mechanism for providing counter-traction while performing dissection, impeding visibility and increasing the rate of complications. There are a multitude of tools available to those performing ESD for the different stages of the procedure. This article reviews the accessories currently used in regular ESD practice including the knives used to cut and dissect lesions, the cap and hood devices used to improve visibility and safety, injection fluids to lift the submucosal plane, haemostatic devices, generators, and finally, emerging traction apparatus. There is some evidence behind the use of these tools, however, ESD remains the domain of a small number of practitioners and the practice relies heavily on expert experience. Evolution of the ESD toolbox will make the procedure more accessible to more endoscopists, which in turn will drive the development of a more substantial evidence base to evaluate efficacy and safety of the multitude of tools.

Endoscopic applications of magnets for the treatment of gastrointestinal diseases

Endoscopic treatment of gastrointestinal diseases has developed rapidly in recent years, due to its minimally invasive nature. One of the main contributing factors for this progress is the improvement of endoscopic instruments, which are essential for facilitating safe and effective endoscopic interventions. However, the slow learning curve required in the implementation of many advanced endoscopic procedures using standard devices is associated with a high risk of complications. Other routine procedures may also be complicated by unexpected difficulties. Based on the ferromagnetic properties of many objects, both internal and external magnetic devices have been developed and applied for multiple endoscopic interventions. The applications of magnets, mainly including compression, anchoring and traction, facilitate many difficult procedures and make it feasible to operate procedures that were previously impossible. Other novel endoscopic applications, such as magnetic nanoparticles, are also under development. In this article, we reviewed published studies of endoscopic applications of magnets for the treatment of gastrointestinal diseases such as precancerous lesions and cancer, obstruction, stricture, congenital and acquired malformations, motility disorders, and ingestion of foreign bodies. Since several endoscopic applications of magnets may also be relevant to surgery, we included them in this review.

Magnetic bead-assisted endoscopic submucosal dissection: a gravity-based traction method for treating large superficial colorectal tumors

BACKGROUND

Colorectal endoscopic submucosal dissection (ESD) has always been challenging for endoscopists, but the procedure can be facilitated after adequate exposure of submucosal layer and cutting line. We developed a traction method based on gravity for facilitating colorectal ESD, referred as magnetic bead-assisted ESD (MBA-ESD). This study aimed to compare the safety and effectiveness of MBA-ESD and conventional ESD for treating large superficial colorectal tumors.

METHODS

This retrospective study included consecutive patients with large (≥ 20 mm in their maximal diameter) superficial colorectal tumors who underwent MBA-ESD or conventional ESD at our endoscopy center between June 2017 to January 2018. Each patient in the MBA-ESD group was matched to a patient in the conventional ESD group using propensity scores.

RESULTS

Thirteen patients in each group were matched for the analyses. The baseline characteristics were balanced after propensity matching. The incidence of overall complications was significantly lower in the matched MBA-ESD group (0% vs. 38.5%, P = 0.039), while similar rates of en bloc resection, R0 resection, curative resection, and tumor recurrence were noted. Although without statistic difference, dissection time and speed were improved when using MBA-ESD (33 min vs. 40 min, P = 0.111; and 21 mm²/min vs. 16 mm²/min, P = 0.143, respectively).

CONCLUSIONS

MBA-ESD is a feasible, safe, and effective method for treating large superficial colorectal tumors. Further large, prospective and controlled studies are needed to fully assess this method.

An internal magnet traction device reduces procedure time for endoscopic submucosal dissection by expert and non-expert endoscopists: ex vivo study in a porcine colorectal model (with video)

BACKGROUND

Efficacy of an internal magnet traction device (MTD) for gastric endoscopic submucosal dissection (ESD) by an expert endoscopist has been reported. We hypothesized that use of the MTD would enhance the performance of colorectal ESD in a non-expert endoscopist in ESD compared to the conventional technique. Primary aim of this study was to compare procedure times between conventional ESD (C-ESD) and MTD-assisted ESD (MTD-ESD) by expert and non-expert endoscopists in ESD. Secondary aims included rate of en bloc resection, iatrogenic injury, visualization score of the submucosal layer, and endoscopist satisfaction score.

METHODS

A total of 56 lesions were created in an ex vivo porcine colorectum. Two endoscopists completed C-ESD (n = 28) and MTD-ESD (n = 28). Lesions measured 3 cm in diameter and were located on either the anterior or posterior colorectal wall. The MTD consisted of a small neodymium magnet and nylon monofilament attached to a through-the-scope clip. The first MTD was deployed on the opposing colorectal wall of the target lesion and a second MTD was then deployed directly onto the distal margin of the lesion.

RESULTS

Total procedure time for MTD-ESD was significantly shorter than C-ESD for both expert (median: 15.8 vs. 19.3 min, p < 0.05) and non-expert (median: 21.3 vs. 33.9 min, p < 0.001) endoscopists. All lesions were resected en bloc. There was no iatrogenic muscularis propria injury in the MTD-ESD group. For both the expert and non-expert, scores for MTD-ESD were significantly higher for submucosal layer visualization (p < 0.05) and endoscopist satisfaction (p < 0.001) compared to C-ESD.

CONCLUSIONS

Use of the MTD significantly reduced procedure time for both expert and non-expert endoscopists performing ESD. Improving the efficiency, safety, and satisfaction of ESD with such a device particularly for non-expert endoscopists is appealing and could potentially minimize the complexity and duration of the procedure allowing for more widespread use of the technique.

Efficacy and safety of an internal magnet traction device for endoscopic submucosal dissection: ex vivo study in a porcine model (with video)

BACKGROUND

Appropriate traction allows for safer and easier endoscopic submucosal dissection (ESD). The aim of this study was to evaluate the efficacy and safety of an internal magnet traction device (MTD) for ESD in an ex vivo porcine model.

METHODS

The MTD consisted of a small neodymium magnet and a suture attached to a through-the-scope clip. A circumferential mucosal incision was completed around a 30-mm diameter template that served as the target lesion. The first MTD was deployed at the proximal edge of the lesion. A second MTD was deployed on the wall opposite the lesion. With both magnets connected, this created traction or lifting of the target lesion towards the opposing wall during submucosal dissection. Primary endpoint was comparison of submucosal dissection times between conventional ESD (C-ESD) and MTD-assisted ESD (MTD-ESD).

RESULTS

Twenty lesions along the anterior wall, posterior wall and greater curvature were resected using either C-ESD or MTD-ESD. The submucosal dissection time in MTD-ESD was significantly shorter than C-ESD (median: 6.4 [interquartile range {IQR} 4.6-8.7] min vs. 14.4 min [IQR 11.8-18.0], p < 0.05). There was a significant difference between MTD-ESD and C-ESD in total procedure times for lesions on the posterior gastric wall and greater curvature (median: 23.0 min [IQR 21.1-24.5] vs. 29.2 min [IQR 24.8-33.2], p < 0.05) with no difference for lesions on the anterior gastric wall (median: 18.8 min [IQR 15.5-20.5] vs. 17.1 min [IQR 13.1-20.0], p = 0.5). The number of muscularis propria injuries per lesion was significantly lower in MTD-ESD than C-ESD (median: 0 [IQR 0-0] vs. 1 [IQR 0-2], p < 0.05).

CONCLUSIONS

MTD for ESD is effective and safe when compared to C-ESD. This approach significantly reduced submucosal dissection times with less injury to the muscularis propria. Furthermore, MTD-ESD was particularly beneficial for more challenging gastric lesions located on the posterior wall and greater curvature.

Electromagnetic assisted endoscopic submucosal dissection is more efficient than water-jet assisted and conventional ESD in experimental model

BACKGROUND AND STUDY AIMS

The adequate visualization of the dissection line, inside the submucosal layer, supposes the main challenging issue in ESD. For this reason, several counter traction methods have been developed focused on overcoming this handicap. One of which, Magnetic anchor guided - ESD (MG-ESD) is an attractive alternative. However, the usefulness of this approach has been scarcely assessed and compared with other ESD strategies. Therefore, the aim of this study is to compare three different ESD alternatives in experimental faction.

METHODS

This was a prospective non-randomized study, in which three different ESD techniques were performed in an ex-vivo gastric porcine model by an endoscopist slight expertise in ESD: conventional ESD, waterjet assisted ESD and MG-ESD. MG-ESD was performed using two different magnets: inner Neodymiun ringed shape magnet attached to the simulated lesions by an endoclip and external electromagnet connected to a Single Output Adjustable 24V/0.3A Power Supply Unit.

RESULTS

Forty-six ESD procedures were performed: 24 conventional ESD, 12 waterjet-assisted ESD and 10 MG-ESD. Average size of the simulated lesions was 33.86 mm. No differences in terms of safety and efficacy were registered between the three approaches. Nevertheless, MG-ESD proved to be faster and more efficient than conventional ESD and water-jet assisted ESD (min per cm ² 10.85 vs. 7.43 vs. 3,41; P  = 0.001).

CONCLUSIONS

MG-ESD could be a feasible alternative to conventional ESD even at the beginning of the learning curve. Therefore, researches focused on developing appropriate ESD magnetic devices and further comparative studies must be promoted, in order to assess the reliable usefulness of the magnet-assistance in ESD.

Robot assisted tumor resection devices

INTRODUCTION

In Japan, colorectal endoscopic submucosal dissection (ESD) is being conducted safely and effectively as shown by the increased number of the cases, however, it is still regarded as a complicated and challenging procedure. Therefore, piecemeal endoscopic mucosal resection (p-EMR) is still regarded as an appropriate treatment, rather than ESD for large colorectal tumors, especially in Western countries. Areas covered: There are several factors those are responsible for colorectal ESD difficulty. Firstly, there is no adequate traction or counter-traction in colorectal ESD. Secondly, it is challenging to handle the colonoscope in a redundant and narrow colonic lumen. Thirdly, the risk of perforation is estimated to be relatively higher compared to the stomach or esophagus Expert commentary: To overcome these difficulties, various traction and counter-traction methods have been reported and finally, the new concept of the Master and Slave Transluminal Endoscopic Robot (MASTER) has been developed and is soon to be available for clinical use. The authors have reviewed the history of colorectal ESD and MASTER in this paper.