Traction-assisted colonic endoscopic submucosal dissection using clip and line: a feasibility study

Effectiveness of Strategy-Focused Training in Colorectal Endoscopic Submucosal Dissection: A Retrospective Observational Study

BACKGROUND

Colorectal ESD, an advanced minimally invasive treatment, presents technical challenges, with globally varying training methods. We analyzed the learning curve of ESD training, emphasizing preoperative strategies, notably gravity traction, to guide ESD instructors and trainee programs.

METHOD

This retrospective study included 881 cases guided by an experienced supervisor. Six trainees received "strategy-focused" instruction. To evaluate the number of ESD experiences in steps, the following phases were classified based on ESD experiences of each trainees: Phase 0 (0-50 ESD), Phase 1 (51-100 ESD), Phase 2 (101-150 ESD), and Phase 3 (151-200 ESD). Lesion background, outcomes, and safety were compared across phases. Factors contributing to technical difficulty in early (Phase 0 and 1) and late phases (Phase 2 and 3) were identified, along with the utility of traction ESD with device assistance.

RESULT

Treatment outcomes were favorable, with 99.8% and 94.7% en bloc resection and curative resection rates, respectively. Approximately 90% self-completion rate could be achieved after experiencing about 50 cases (92.7% in Phase 1), signifying proficiency growth despite increased case difficulty. In early phases, factors such as left-sided colon, LST-NG morphology, and severe fibrosis pose challenges. In late phases, LST-NG morphology, mild and severe fibrosis remained significant. Traction-assisted ESD, utilized in 3% of cases, comprised planned (1.1%) and rescue (1.9%) methods. Planned traction aided specific lesions, while rescue traction was common in the right colon.

CONCLUSION

"Strategy-focused" ESD training consistently yields successful outcomes, effectively adapting to varying difficulty factors in different proficient stages.

Conventional Versus Traction-Assisted Endoscopic Submucosal Dissection for Esophageal, Gastric, and Colorectal Neoplasms: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Endoscopic submucosal dissection (ESD) is increasingly being utilized for the resection of superficial gastrointestinal neoplasms. However, the long procedure time poses a technical challenge for conventional ESD (C-ESD). Traction-assisted ESD (T-ESD) was developed to facilitate the procedure by reducing its duration. This study compares the efficacy and safety of C-ESD versus T-ESD in the treatment of esophageal, gastric, and colorectal neoplasms. Nine randomized controlled trials (RCTs) were analyzed. Traction-assisted ESD exhibited shorter mean dissection times for the esophagus and colorectal regions and lower perforation rates in colorectal cases. No significant differences were observed in en bloc resection or bleeding rates. Traction-assisted ESD proves to be more efficient in mean procedure time for esophageal and colorectal cases and safer in perforation rates for colorectal cases, but similar rates are noted for en bloc resection or bleeding.

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.

Predictive Factors for the Outcome of Unsupervised Endoscopic Submucosal Dissection During the Initial Learning Curve with Prevalence-Based Indication

BACKGROUND

For an adequate educational strategy of ESD in non-Asian settings with prevalence-based indication it is essential to define adequate lesions, suitable for the beginner without on-site expert-supervision.

AIMS

We analyzed possible predictors for outcome parameters of effectiveness and safety during the initial learning curve.

METHODS

The first 120 ESDs of four operators (n = 480), performed between 2007 and 2020 in four tertiary hospitals, were enrolled. Uni-/multivariable regression analysis was done with sex, age, pretreated lesion, lesion size, organ, and organ-based localization as possible independent predictors for en bloc resection (EBR), complication, and resection speed.

RESULTS

Rates of EBR, complication, and resection speed were 84.5%, 14.2%, and 6.20 (± 4.45) cm2/h. Independent predictors for EBR were pretreated lesion (OR 0.27 [0.13-0.57], p < 0.001) and non-colonic ESD (OR 2.29 [1.26-4.17] (rectum)/5.72 [2.36-13.89] (stomach)/7.80 [2.60-23.42] (esophagus), p < 0.001), for complication pretreated lesion (OR 3.04 [1.46-6.34], p < 0.001) and lesion size (OR 1.02 [1.004-1.04], p = 0.012) and for resection speed pretreated lesion (RC - 3.10 [- 4.39 to - 1.81], p < 0.001), lesion size (RC 0.13 [0.11-0.16], p < 0.001) and male patient (RC - 1.11 [- 1.85 to - 0.37], p < 0.001). We found no significant difference in the incidence of technically unsuccessful resections in esophageal (1/84), gastric (3/113), rectal (7/181), and colonic (3/101) ESDs (p = 0.76). Technical failure was mainly caused by complication and fibrosis/pretreatment.

CONCLUSION

During the initial learning curve of an unsupervised ESD program with prevalence-based indication, pretreated lesions and colonic ESDs should be avoided. In contrast, lesion size and organ-based localizations have less predictive value for the outcome.

Comparison Between Preincision Traction and On-Demand Traction in Assisting Colorectal Endoscopic Submucosal Dissection

INTRODUCTION

Adequate exposure of the dissection site is very important for colorectal endoscopic submucosal dissection (ESD). We aimed to investigate the safety and efficacy of the preincision traction (PIT) method using an internal clip-with-spring device in comparison with the conventional on-demand traction (ODT) method in assisting colorectal ESD.

METHODS

This was a prospective nested case-control study. A total of 26 patients for PIT-ESD and other 26 patients for ODT-ESD were involved. Data on clinical characteristics and therapeutic outcomes were collected and analyzed.

RESULTS

The en bloc resection rate (both 100%) and curative resection rate (92.3% vs 96.2%) showed no significant difference between the 2 groups. Compared with ODT-ESD, PIT-ESD significantly reduced the procedure time (29.8 ± 18.4 vs 57.4 ± 33.7 minutes, P = 0.001) and submucosal injection volume (49.6 ± 32.3 vs 70.8 ± 37.6 mL, P = 0.034), decreased the rate of intraoperative bleeding (26.9% vs 57.7%, P = 0.025) and muscular injury (7.7% vs 34.6%, P = 0.038), and shortened the postoperative hospital stay (1.8 ± 0.8 vs 2.5 ± 1.2, P = 0.015).

DISCUSSION

The PIT method could significantly improve the safety and efficacy of colorectal ESD.

Advancing endoscopic traction techniques in endoscopic submucosal dissection

Traction techniques have emerged as a desirable "second-hand" while performing endoscopic submucosal dissection (ESD), enabling adequate visualization of submucosal tissue and vasculature, which allows for safe and efficient dissection. Multiple traction techniques have been developed over the years, and these can be broadly divided into internal and external traction techniques. This arsenal of techniques allows for traction that is personalized to the location of the lesion undergoing ESD. Mastering traction techniques requires structured training, and understanding of the benefits and pitfalls of each technique. Future research and development efforts need to focus on pathways and curriculums for trainees to master the currently available endoscopic traction techniques and provide avenues for the development of newer traction modalities.

Multi-loop traction device facilitates gastric endoscopic submucosal dissection: ex vivo pilot study and an inaugural clinical experience

BACKGROUND

Endoscopic submucosal dissection (ESD) is technically difficult and requires considerable training. The authors have developed a multi-loop traction device (MLTD), a new traction device that offers easy attachment and detachment. We aimed to evaluate the utility of MLTD in ESD.

METHODS

This ex vivo pilot study was a prospective, block-randomized, comparative study of a porcine stomach model. Twenty-four lesions were assigned to a group that undertook ESD using the MLTD (M-ESD group) and a group that undertook conventional ESD (C-ESD group) to compare the speed of submucosal dissection. In addition, the data of consecutive 10 patients with eleven gastric lesions was collected using electronic medical records to clarify the inaugural clinical outcomes of gastric ESD using MLTD.

RESULTS

The median (interquartile range) speed of submucosal dissection in the M-ESD and C-ESD groups were 141.5 (60.9-177.6) mm2/min and 35.5 (20.8-52.3) mm2/min, respectively; submucosal dissection was significantly faster in the M-ESD group (p < 0.05). The rate of en bloc resection and R0 resection was 100% in both groups, and there were no perforation in either group. The MLTD attachment time was 2.5 ± 0.9 min and the MLTD extraction time was 1.0 ± 1.1 min. Clinical outcomes of MLTD in gastric ESD were almost the same as those of ex vivo pilot study.

CONCLUSIONS

MLTD increased the speed of submucosal dissection in ESD and was similarly effective when used by expert and trainee endoscopists without perforation. MLTD can potentially ensure a safer and faster ESD.

Endoscopic submucosal dissection: How to be more efficient?

Endoscopic submucosal dissection (ESD) allows an "en bloc" resection with safety margins (R0 resection) regardless of the size of the lesion. However, while R0 brings a real benefit for the patient, it is not considered sufficient by many experts to justify the technical difficulties and the longer procedure time compared to piecemeal mucosectomy. The aims of this review are to provide several technical and strategical tips to help you save time and become comfortable during ESD procedures. ESD is divided into several intertwined phases: injection, incision, access to the submucosae, and submucosal dissection itself. During injection there are some mistakes that should not be made: a superficial injection, or on the contrary, a too deep injection. A good needle and good injection technique are mandatory. Some techniques, such as repeated injection or prolonged lifting solution, can help maintain the lift. After this step, mucosal incision can be made, taking care to have a good margin to allow an R0 resection. Starting the mucosal incision from a small point allows calibration of the depth of the incision and then obtaining a nice incision. Trimming is also very important to widen submucosal access. Then comes the submucosal dissection itself. Strategies such as the tunnel strategy or the pocket creation method can help to facilitate dissection, but more importantly, traction systems have become unavoidable, especially in the stomach and colon. Most common complications are bleeding and perforation, and they usually can be managed endoscopically.

Endoscopic Submucosal Dissection Using EndoTrac, a Novel Traction Device

BACKGROUND

Endoscopic submucosal dissection (ESD) is recognized as a minimally invasive and curative treatment for superficial gastrointestinal (GI) cancers. However, ESD is still challenging and time-consuming with a high risk of adverse events such as bleeding and perforation. Various traction methods have been explored for maintaining good visualization of the submucosal layer during ESD. We developed a novel traction device (the EndoTrac) which can easily tie the thread and has the ability to change the towing direction. The aim of this study is to evaluate safety and feasibility of ESD using the EndoTrac for GI neoplasms.

PATIENTS AND METHODS

We retrospectively analyzed 44 patients (45 lesions) with esophageal, gastric, duodenal, and colorectal neoplasms who had undergone ESD using the EndoTrac device between June 2018 and May 2019. Primary outcome measures were preparation time, procedural success using the EndoTrac device, and ease of ability to change towing direction.

RESULTS

Mean preparation time was 2 (2-5) min in esophagus, 3 (1-5) min in stomach, 6 (5-9) min in duodenum, and 4 (2-8) min in colorectum. The procedural success rate was 100% (8/8) in esophagus, 100% (21/21) in stomach, 100% (4/4) in duodenum, and 100% (12/12) in colorectum. The rate of successful towing to both proximal and distal sides was 100% (8/8) in esophagus, 100% (21/21) in stomach, 0% (0/4) in duodenum, and 100% (12/12) in colorectum.

CONCLUSIONS

Use of the EndoTrac device appears to be a feasible approach to ESD for GI neoplasms.

Double-clip traction could be superior to the pocket-creation method with cylindrical cap for colonic ESD: a randomized study in an ex vivo model

INTRODUCTION

In Western countries, debates between ESD vs piece-meal EMR as the best treatment for large colorectal adenomas persist regarding the difficulty of ESD the colon, and the safety and relatively good results of piece-meal endoscopic mucosal resection (EMR). Pocket-creation method (PCM) and double-clip countertraction (DCT) are two strategies recently published to facilitate ESD in this challenging situation.

METHOD

This is a randomized animal study to compare PCM and DCT strategies for colonic ESD on ex vivo models (bovine colon) performed by 3 operators novice in ESD. Hybridknife type T was used to inject normal saline tinted with a small amount of blue dye in all procedures. Randomization was stratified according to the use of gravity assist. Primary endpoint was the difference in resection speed between PCM and DCT strategies.

RESULTS

Resection speed was significantly higher in the DCT group than in the PCM group (56.3 vs. 31.6 mm²/min, p = 0.01). Technical success rate, defined as en bloc resection in under 60 min, was significantly better in the DCT group than in the PCM group (100% vs. 84.4%, p = 0.024), perforation rate was lower (0% vs. 18.8%, p = 0.012), and difficulty score was better (2.4 vs. 6.2, p < 0.0001) as was procedure duration (24.2 vs. 40.2 min, p < 0.0001).

CONCLUSION

DCT was superior to PCM for ESD in our validated bovine colon model. This strategy is inexpensive, easy to use and adaptive. It might facilitate the widespread use of colonic ESD in Western countries and change Western ideas regarding the use of colonic ESD compared with piece-meal EMR for large benign lesions.

Factors influencing interruption of colorectal endoscopic submucosal dissection

BACKGROUND AND AIMS

Although colorectal endoscopic submucosal dissection (ESD) has become a standardized procedure worldwide, the difficulty of the procedure is well known. However, there have been no studies assessing the causes of treatment interruption. The present study aimed to evaluate the factors involved in the interruption of colorectal ESD.

METHODS

We retrospectively analyzed 1116 consecutive superficial colorectal neoplasms of 1012 patients who were treated with ESD between August 2008 and September 2018. The clinicopathological characteristics and treatment outcomes were analyzed.

RESULTS

Interrupted ESD was reported in 14 lesions (1.3%) of the total study population. Univariate analysis of clinical characteristics indicated that age, 0-I macroscopic-type tumor, and tumor location on the left side colon were risk factors for interruption. Multivariate analysis revealed that 0-I macroscopic-type tumor was the sole preoperative independent risk factor for interruption. Univariate analysis revealed that the presence of muscle-retracting sign (MRS), deep submucosal tumor invasion, and intermediate invasive growth pattern represented the etiology of interruption. Multivariate analysis indicated that MRS can be a sole key sign for the interruption. Additionally, the resectability and curability of 0-I type tumors were significantly inferior to those of predominantly lateral spreading tumors. Observations of 0-I macroscopic-type tumors, MRS, and submucosal deep invasion were significantly more frequent in interrupted cases. Conventional endoscopic images without magnification endoscopy were more associated with interruption than irregular surfaces or Vi pit patterns in cases with 0-I type tumors.

CONCLUSION

ESD of 0-I type tumors is highly disruptive, and undiagnosable submucosal infiltration can reduce the curability.

Clinical usefulness of the S-O clip during colorectal endoscopic submucosal dissection in difficult-to-access submucosal layer

Background and study aims  In colorectal endoscopic submucosal dissection (ESD), the S-O clip improves the accessibility to the submucosal layer of the colon. However, its safety and usefulness in difficult colorectal ESDs are unclear. Thus, in this study, we aimed to assess the effectiveness of the S-O clip in colorectal ESD in the difficult-to-access submucosal layer. Patients and methods  From January 2016 to December 2016, 189 consecutive cases of colorectal ESD were performed at Hiroshima University Hospital before the S-O clip was introduced. Between January 2017 and June 2018, among 271 consecutive colorectal ESD cases, 41 cases were performed colorectal ESD using the S-O clip. We compared outcomes between the two groups (41 cases with S-O clip [use group] and 189 cases without S-O clip [non-use group]) using propensity score matching. Results  Prior to propensity score matching, 41 cases with the S-O clip (use group) and 189 cases without the S-O clip (non-use group) were extracted. The degree of submucosal fibrosis was more severe and the procedure time was longer in the use group than in the non-use group. In the use and non-use groups, en bloc resection (100 % vs. 94.7 %) and complete en bloc resection (100 % vs. 92.6 %) rates were satisfactory. After propensity score matching, 33 cases in each group were extracted. As a result, complete en bloc resection rate was significantly higher in the use group than in the non-use group (100 % vs. 84.9 %). Conclusion  The S-O clip is effective and can be used safely in colorectal ESD in the difficult-to-access submucosal layer.

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.

Short-term outcomes of traction-assisted versus conventional endoscopic submucosal dissection for superficial gastrointestinal neoplasms: a systematic review and meta-analysis of randomized controlled studies

Background

In recent years, some traction-assisted approaches have been introduced to facilitate endoscopic submucosal dissection (ESD) procedures by reducing the procedure time and risks related to the procedure. However, the relative advantages of traction-assisted endoscopic submucosal dissection (T-ESD) are still being debated. This study aimed to assess the efficacy of T-ESD for the treatment of superficial gastrointestinal neoplasms.

Methods

We searched MEDLINE, Embase, and Cochrane library up to March 31, 2019 for randomized controlled trials (RCTs) comparing T-ESD and conventional endoscopic submucosal dissection (C-ESD) for superficial gastrointestinal neoplasms. The main endpoints are en bloc resection, complete resection, procedure time, perforation, and delayed bleeding. Pooled risk ratio (RR), Peto odds ratio (OR), and mean difference (MD) were calculated to compare T-ESD and C-ESD. This study is registered with PROSPERO, number CRD42018108135.

Results

A total of 7 RCTs with 1007 patients were included in this meta-analysis. There were no significant differences between the T-ESD and C-ESD groups in the pooled estimate of en bloc resection, complete resection, and delayed bleeding (RR = 1.00, 95% CI 0.99, 1.01, I² = 0%, P = 0.66; RR = 1.00, 95% CI 0.98, 1.03, I² = 0%, P = 0.81; OR = 0.95, 95% CI 0.48, 1.86, I² = 19%, P = 0.87,respectively). The pooled estimate indicated that the procedure time was significantly shorter in the T-ESD group (MD = − 16.19, 95% CI − 29.24, − 3.13, I² = 87%, P = 0.02) than in the C-ESD group. Compared to C-ESD, T-ESD was associated with lower incidence of perforation (OR = 0.32, 95% CI 0.11, 0.91, I² = 0%, P = 0.03).

Conclusions

T-ESD is a safe and effective treatment option with a low perforation rate and shorter procedure time than C-ESD for superficial gastrointestinal neoplasms. Future multi-center (including European populations), randomized controlled trials of larger sample size and long-term outcomes of T-ESD are required.

Colorectal endoscopic submucosal dissection can be efficiently performed by a trainee with use of a simple traction device and expert supervision

Background and study aims  Colorectal endoscopic submucosal dissection (ESD) is technically challenging owing to submucosal fibrosis and difficult endoscope manipulation. Therefore, various traction methods have been reported. We often use a simple looped nylon thread attached to a clip to assist with dissection. We assessed the feasibility of mentor-guided colorectal ESD using this traction device (TD). Patients and methods  From December 2017 to March 2018, we retrospectively reviewed outcomes of 101 colorectal ESDs performed by two groups of endoscopists (A, 5 endoscopists with colorectal ESD experience of < 50 cases; B, 5 endoscopists with experience of > 300 cases). Group A was further divided into two subgroups that performed ESD with or without TD. Results  No significant difference was observed in ESD completion rates (86.1 % [62/72] vs. 96.6 % [28/29]; odds ratio [OR], 0.22; 95 % confidence interval [CI], 0.005 - 1.71; P  = 0.17) or procedure times (52.0 min vs. 40.0 min; P  = 0.27) and adverse event rates between groups A and B. The rate of TD use was significantly higher in group A than in group B (44.4 % [32/72] vs. 20.7 % [6/29]; OR, 3.03; CI, 1.04 - 10.23; P  = 0.03). The completion rate was not different between the two subgroups of group A (with vs. without TD) (81.2 % [26/32] vs. 90.0 % [36/40]; OR, 0.49; CI, 0.09 - 2.29; P  = 0.32); however, the proportion of fibrosis cases was significantly higher in the TD-use group (46.8 % [15/32] vs. 22.5 % [9/40]; OR, 2.99; CI, 0.98 - 9.59; P  = 0.03). Conclusion  Mentor-guided colorectal ESD using TD was performed efficiently, safely, and in a manner comparable to that of experts.

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.

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.

Recent Development of Techniques and Devices in Colorectal Endoscopic Submucosal Dissection

Colorectal endoscopic submucosal dissection (ESD) is now a well-established endoscopic treatment for early-stage colorectal neoplasms, especially in Asian countries, including Japan. Despite the spread of colorectal ESD, there are still situations in which achieving successful submucosal dissection is difficult. Various novel techniques and devices have been developed to overcome these difficulties, and past reports have shown that some of these strategies can be applied to colorectal ESD. We review several recent developments in the field. The techniques reviewed include the pocket creation method and traction methods and the devices reviewed include the overtube with balloon and electrosurgical knives with water-jet function. These improved techniques and devices can facilitate safer, more reliable ESDs and expand its applicability and acceptability all over the world.

Colorectal endoscopic submucosal dissection: predictors and neoplasm-related gradients of difficulty

BACKGROUND AND STUDY AIM

 The role of colorectal endoscopic submucosal dissection (ESD) is standardized in Japan and East Asia, but technical difficulties hinder its diffusion. The aim was to identify predictors of difficulty for each neoplasm type.

METHODS

 A competent operator performed all procedures. ESD difficulty was defined as: en bloc with a slow speed (< 0.07 cm ² /min; 30 × 30 mm neoplasm in > 90 min), conversion to endoscopic mucosal resection, or resection abandonment. Pre- and intraoperative difficulty variables were defined according to standard criteria, and evaluated separately for the rectum and colon. Difficulty predictors and gradients were evaluated by the multivariate logistic regression model.

RESULTS

 A total of 140 ESDs were included: 110 in the colon and 30 in the rectum. Neoplasms were laterally spreading tumors - granular type (LST-G) in 85 cases (61 %); the median longer axis was 30 mm (range 15 - 180 mm); a scar was present in 15 cases (11 %). ESD en bloc resection and difficulty rates were 85 % (n = 94) and 35 % (n = 39) in the colon, and 73 % (n = 22) and 50 % (n = 15) in the rectum ( P  = 0.17 and 0.28, respectively). The scar was the only preoperative predictor of difficulty in the rectum (odds ratio [OR] 12.3, 95 % confidence interval [CI] 1.27 - 118.36), whereas predictors in the colon were: scar (OR 12.7, 95 %CI 1.15 - 139.24), LST - nongranular type (NG) (OR 10.5, 95 %CI 1.20 - 55.14), and sessile polyp morphology (OR 3.1, 95 %CI 1.18 - 10.39). Size > 7 - ≤ 12 cm ² (OR 0.20, 95 %CI 0.06 - 0.74) and operator experience > 120 procedures (OR 0.19, 95 %CI 0.04 - 0.81) were predictors for a easy procedure. No intraoperative predictors of difficulty were identified in the rectum, whereas predictors in the colon were: severe submucosal fibrosis (OR 21.9, 95 %CI 2.11 - 225.64), ineffective submucosal exposure by gravity countertraction (OR 12.3, 95 %CI 2.43 - 62.08), and perpendicular submucosal dissection approach (OR 5.2, 95 %CI 1.07 - 25.03). When experience was /= 90, preoperative gradient of colonic ESD difficulty was the highest for LST-NGs (scar positive and negative up to 47 % and 20 %, respectively), intermediate for sessile polyps with scar (up to 23 %), and the lowest for LST-Gs (< 8 %). Different difficulty gradients between neoplasm types persisted with increasing experience: LST-NG rate up to 14 % after 120 procedures.

CONCLUSIONS

 Colonic and rectal ESD difficulty has qualitative differences. Preoperative predictors should be considered to identify the difficulty gradient of each neoplasm type and the appropriate setting for ESD.

Novel effective and repeatedly available ring-thread counter traction for safer colorectal endoscopic submucosal dissection

Background

Although several methods to create an effective counter traction for safer endoscopic submucosal dissection (ESD) have been reported, these methods do not overcome problems regarding delivery and ease of use. This randomized prospective study assessed the usefulness of ring-shaped thread counter traction, which not only allowed the safer colorectal ESD but also the easiest and lower cost counter traction without any special devices.

Methods

Forty-five patients diagnosed with colorectal lateral spreading tumors over 20 mm were allocated to the conventional ESD group (CE) (n = 22) and the ring-shaped thread counter traction ESD group (RE) (n = 21). The ring-shaped thread was hooked and lifted up to the contralateral mucosa with a hemoclip. The primary outcome was the dissected area per minute during ESD (cm²/min) (UMIN000020160).

Results

There were significant differences in the dissection time (min), with 130.0 (56.0–240.0) versus 80 (35.0–130.0) min for the CE and RE groups, respectively (P = 0.001). For the dissected areas per minute (cm²/min), there was a significant difference, with 0.125 (0.1–0.18) versus 0.235 (0.16–0.36) min (P = 0.003) for the CE and RE groups, respectively. There were 1 cases of perforation during ESD in the CE compared to 0 for the RE, and this was no significantly different (P = 0.31). The procedure time of producing and setting the ring-shaped thread counter traction was approximately 1.80 (0.80–3.30) min only.

Conclusions

The ring-shaped thread counter traction is simple, effective, lower cost and does not require special devices to obtain repeated counter traction.

Electronic supplementary material

The online version of this article (doi:10.1007/s00464-016-5326-7) contains supplementary material, which is available to authorized users.

Recent traction methods for endoscopic submucosal dissection

Endoscopic mucosal resection (EMR) is problematic with regard to en bloc and curable resection rates. Advancements in endoscopic techniques have enabled novel endoscopic approaches such as endoscopic submucosal dissection (ESD), which has overcome some EMR problems, and has become the standard treatment for gastrointestinal tumors. However, ESD is technically difficult. Procedure time is longer and complications such as intraoperative perforation and bleeding occur more frequently than in EMR. Recently various traction methods have been introduced to facilitate ESD procedures, such as clip with line, external forceps, clip and snare, internal traction, double scope, and magnetic anchor. Each method must be used appropriately according to the anatomical characteristics. In this review we discuss recently proposed traction methods for ESD based on the characteristics of various anatomical sites.