Robotic Platforms for Therapeutic Flexible Endoscopy: A Literature Review.

Flexible endoscopy, initially developed for diagnosis and tissue sampling, has been adapted for therapeutic interventions, leading to the emergence of natural orifice transluminal endoscopic surgery (NOTES) in the 2000s. The need for a triangulation function to enhance the intuitiveness and safety of NOTES has prompted the development of dual-arm, flexible endoscopic robotic platforms. Although the global interest in NOTES has decreased in the last decade, no-scar surgery concepts are still being applied to other complex endoluminal interventions, such as endoscopic submucosal dissection (ESD) and endoscopic full-thickness resection (EFTR), with ongoing research and development. The application of robotics in flexible endoscopy may facilitate the standardization of these procedures and expedite their global spread. Various robotic platforms have been developed and tested in the preclinical and clinical settings to demonstrate their efficacy and safety. In this article, we review the publications on technology and elucidate their advantages and existing challenges.

Diagnostic Performance of a Novel Ultra-Thin Endoscopy under Narrow-Band Imaging for Superficial Squamous Cell Carcinoma of the Pharynx and Esophagus.

This study aimed to evaluate the diagnostic utility of the ultra-thin endoscope (UTE) for superficial squamous cell carcinoma (SSCC) compared to magnifying endoscopy (ME) under narrow-band imaging. Participants underwent endoscopic examination, and images of pharyngeal and esophageal SCCs, as along with suspicious SSCC lesions, were collected using UTE and ME on the same day. Three image catalogs (UTE, ME-1, and ME-2) were created and reviewed by three expert endoscopists. ME-1 and ME-2 contained the same endoscopic images. The primary endpoint was the intra-observer agreement for diagnosing SCC. Eighty-six lesions (SCC = thirty-nine, non-SCC = forty-seven) in 43 participants were identified. The kappa values for the intra-observer agreement between UTE and ME-1 vs. the control (ME-1 vs. ME-2) were 0.74 vs. 0.84, 0.63 vs. 0.76, and 0.79 vs. 0.88, respectively. The accuracies for diagnosing SCC by UTE and ME-1 were 87.2% vs. 86.0%, 78.0% vs. 73,2%, and 75.6 vs. 82.6%, respectively, with no significant differences (p > 0.05). The rates of lesions that were diagnosed with confidence by UTE and ME-1 were 30.2% vs. 27.9%, 55.8% vs. 62.8%, and 58.1% vs. 55.8%, respectively. UTE demonstrates substantial diagnostic performance for SSCC in the pharynx and esophagus.

Clinical outcomes of the over-the-scope clip closure after duodenal endoscopic submucosal dissection: A multicenter retrospective study.

BACKGROUND AND AIM: Prophylactic closure with the over-the-scope clip (OTSC) after endoscopic submucosal dissection (ESD) of superficial non-ampullary duodenal epithelial tumors (SNADETs) has been reported to reduce postoperative adverse events (AEs). However, there are few evidences regarding AEs-associated factors and long-term outcomes of OTSCs. METHODS: From January 2011 to December 2020, 139 consecutive patients with SNADETs who underwent ESD followed by OTSC closure in five institutions were extracted in this retrospective study. The primary endpoint was the rate of postoperative AEs after prophylactic OTSC closure. The secondary endpoints were the complete closure rate, residual rate, and long-term AEs associated with residual OTSCs. RESULTS: The rate of complete closure of the mucosal defect was 97.3% (142) in 146 SNADETs, which were completely resected by ESD. Postoperative AEs, including delayed bleeding, delayed perforation, and localized peritonitis, occurred in 6.2%, 3.4%, and 2.1% of patients, respectively; however, all of the cases improved without surgical treatment. In the multivariate logistic regression analysis, the use of two or more OTSCs was a significant independent risk factor for postoperative AEs (odds ratio, 2.94; 95% confidence interval, 1.02-8.46; P = 0.046). The residual OTSC rate was 46.4% at 1 year postoperatively, and long-term AEs included duodenal erosions and ulcers associated with residual OTSCs. CONCLUSIONS: Prophylactic closure with OTSCs after duodenal ESD can provide acceptable short-and long-term outcomes for preventing postoperative AEs. However, multiple OTSCs were the independent risk factors of postoperative AEs due to the gaps between and near the OTSCs.

Novel endoscopic duodenal observation protocol based on Seven Pictures Rule for detecting duodenal neoplasms during esophagogastroduodenoscopy: Prospective observational study.

OBJECTIVES: No protocol for esophagogastroduodenoscopic examination of the duodenum has been established. We examined the feasibility and ability to detect neoplasms of a novel duodenal examination protocol. METHODS: This was a two-facility, prospective, observational study. Our protocol, the Seven Pictures Rule (7PR), requires pictures of the following seven locations: anterior and posterior to the bulb, area of and contralateral to the superior duodenal angle, area of and contralateral to the ampulla, and the transverse duodenum. The primary outcome was rate of completion of 7PR. Secondary outcomes were overall rates of detecting neoplasms, rates of detecting neoplasms for each location, examination time, and completion rates for standard or ultrathin endoscopes. RESULTS: There were 1549 participants. The 7PR completion rate was 81.1% and the detection rates of overall neoplasms, adenomas, and carcinomas were 0.84%, 0.71%, and 0.06%, respectively. The area in which most neoplasms was detected was contralateral to the ampulla (69.2%), and the fewest the transverse duodenum (0%). Mean duration of duodenal examination was 53.1 s. Completion rates for standard vs. ultrathin were 84.4% (1077/1276) vs. 65.6% (179/273) (P < 0.01), respectively. CONCLUSIONS: Seven Pictures Rule is acceptable for duodenal examination and a potential quality indicator.

Outcomes of Endoscopic Intervention Using Over-the-Scope Clips for Anastomotic Leakage Involving Secondary Fistula after Gastrointestinal Surgery: A Japanese Multicenter Case Series.

BACKGROUND: The over-the-scope clip (OTSC) is a highly effective clipping device for refractory gastrointestinal disease. However, Japanese data from multicenter studies for anastomotic leakage (AL) involving a secondary fistula after gastrointestinal surgery are lacking. Therefore, this study evaluated the efficacy and safety of OTSC placement in Japanese patients with such conditions. METHODS: We retrospectively collected data from 28 consecutive patients from five institutions who underwent OTSC-mediated closure for AL between July 2017 and July 2020. RESULTS: The AL and fistula were located in the esophagus (3.6%, n = 1), stomach (10.7%, n = 3), small intestine (7.1%, n = 2), colon (25.0%, n = 7), and rectum (53.6%, n = 15). The technical success, clinical success, and complication rates were 92.9% (26/28), 71.4% (20/28), and 0% (0/28), respectively. An age of <65 years (85.7%), small intestinal AL (100%) and colonic AL (100%), defect size of <10 mm (82.4%), time to OTSC placement > 7 days (84.2%), and the use of simple suction (78.9%) and anchor forceps (80.0%) were associated with higher clinical success rates. CONCLUSION: OTSC placement is a useful therapeutic option for AL after gastrointestinal surgery.

Current Status of Endoscopic Full-Thickness Resection for Gastric Subepithelial Tumors: A Literature Review Over Two Decades.

BACKGROUND: With the development of endoscopic technology and devices, endoscopic full-thickness resection (EFTR) has been challengingly introduced for gastric subepithelial tumors (SETs). The resection and closure strategies are under investigation. This systematic review was performed to assess the current status and limitations of EFTR for gastric SETs. SUMMARY: MEDLINE was searched using the keywords "endoscopic full-thickness resection" or "gastric endoscopic full-thickness closure" AND "gastric" or "stomach" from January 2001 to July 2022. The outcome variables were the complete resection rate, major adverse event (AE) rate including delayed bleeding and delayed perforation, and closure-associated outcomes. Among 288 studies, 27 eligible studies involving 1,234 patients were included in this review. The complete resection rate was 99.7% (1,231/1,234). The major AE rate was 1.13% (14/1,234), with delayed bleeding in two (0.16%) patients, delayed perforation in one (0.08%), panperitonitis or abdominal abscess in three (0.24%), and other AEs in eight (0.64%). Surgical interventions were required intraoperatively or postoperatively in 7 patients (0.56%). Three patients underwent intraoperative conversion to surgery, due to intraoperative massive bleeding, technical difficulty of closure, and retrieval of falling tumor in the peritoneal cavity. Postoperative surgical rescues for AEs were required in four (0.32%). Subgroup analysis of AE outcomes showed no significant differences among closure techniques consisting of endoclips, purse-string suturing, and over-the-scope clips. KEY MESSAGES: This systematic review demonstrated acceptable outcomes of EFTR and closure for gastric SETs, indicating that EFTR is a promising forthcoming procedure.

Effective and Secure Closure after Duodenal Endoscopic Submucosal Dissection: Combination of Endoscopic Ligation with O-Ring Closure and Over-the-Scope Clip.

Duodenal endoscopic submucosal dissection (ESD) is associated with high incidences of intraoperative complications and delayed adverse events (AEs). Delayed AEs can be reduced by closing the post-ESD defects. We developed a new method of closure after duodenal ESD, combining endoscopic ligation with O-ring closure (E-LOC) with an over-the-scope clip (OTSC) (Band OTSC; B-OTSC). Here, we conducted a single-center, retrospective, observational study to investigate the efficacy and safety of the B-OTSC method for preventing delayed AEs in patients undergoing duodenal ESD. The study included nine patients with superficial nonpapillary duodenal epithelial tumors who underwent ESD and were closed with B-OTSC from February 2021 to February 2023. There were no delayed AEs (0%), the mean (± standard deviation) closure time was 53 ± 21.6 min, the complete closure rate was 100%, and the mean hospital stay was 7.8 ± 1.8 days. The sustained closure rates at postoperative days 3 and 7 were 88.9% and 88.9%, respectively. The historical analysis indicated a significant difference in cost between B-OTSC and conventional OTSC (p < 0.01). In conclusion, B-OTSC was a safe, secure, and cost-effective method of closure after duodenal ESD, even in patients with post-ESD defects of more than half the circumference.

Does an Extraoral Suction Device Reduce Aerosol Generation and Prevent Droplet Exposure to the Examiner during Esophagogastroduodenoscopy?

Esophagogastroduodenoscopy (EGD) is an aerosol-generating procedure. A major challenge in the COVID-19 era is how to prevent the spread of aerosols and droplets in endoscopic units. We evaluated the effectiveness of an extraoral suction device in preventing indoor aerosol diffusion and droplet exposure for examiners. The study involved 61 patients who underwent EGD at our institution from 1 February to 31 March 2022. To determine whether aerosol spread increases before or after EGD examination with an extraoral suction device located in front of the patient's mouth, aerosols of 0.3, 0.5, 1, 3, 5, and 10 µm were measured with a handheld particle counter. The degree of contamination of the plastic gowns on the examiners was assessed using the rapid adenosine triphosphate test. The extraoral suction device significantly reduced the diffusion of large particles (3, 5, and 10 µm) after finishing the EGD examination. However, the diffusion of small particles (0.3 and 0.5 µm) was significantly increased. This extraoral suction device was effective in reducing large particle diffusion during EGD examination but was limited for minimizing small particle diffusion or droplet exposure to the examiner.

Comparison of Needle Knife versus Scissors Forceps for Colorectal Endoscopic Submucosal Dissection: A Prospective Randomized Study.

BACKGROUND AND AIM: To evaluate the efficacy and safety of a grasping-type knife, called Clutch Cutter (CC), for colorectal endoscopic submucosal dissection (C-ESD). METHODS: This was a randomized prospective study. Patients who underwent C-ESD for colorectal neoplasms >20 mm and <50 mm in size were enrolled, dividing into two groups: ESD using needle type of dual knife alone (D-group) and circumferential incision using dual knife followed by submucosal dissection using CC (CC-group). The primary outcome was the self-completion rate. The secondary outcomes were intraoperative complication rate, procedure time, and en bloc resection rate. RESULTS: A total of 45 patients were allocated to the D-group and 43 to the CC-group were allocated. The self-completion rate was higher in the CC-group (87% [39/45] vs. 98% [42/43]). All of the six patients with an incomplete procedure in the D-group were completely resected with CC use. The intraoperative complication rate was not significant in either group (D vs. CC: 2% vs. 0%). The mean procedure time was significantly shorter in the D-group than that in the CC-group (62.0 vs. 81.1 min; p = 0.0036). The en bloc resection rate was 100% in the D-group and 98% in the CC-group. CONCLUSIONS: While dual knife use is superior to CC in terms of time efficiency, the use of CC may be a safe and efficacious option for achieving complete C-ESD.

Comparison of endoscopic closure versus non-closure for post-gastric endoscopic submucosal dissection artificial floor in antithrombotic therapy: a propensity score-matched analysis.

Background: The management of delayed bleeding after gastric endoscopic submucosal dissection (ESD) is currently an important issue because of recent increases in the number of patients on antithrombotic therapy. Artificial ulcer closure has been shown to prevent delayed complications in the duodenum and colon. However, its effectiveness in cases involving the stomach remains unclear. In this study, we aimed to determine whether endoscopic closure reduces post-ESD bleeding in patients undergoing antithrombotic therapy. Methods: We retrospectively analyzed 114 patients who had undergone gastric ESD while on antithrombotic therapy. The patients were allocated to one of 2 groups: a closure group (n=44) and a non-closure group (n=70). Endoscopic closure had been performed using multiple hemoclips or using the endoscopic ligation with O-ring closure method after coagulation of exposed vessels on the artificial floor. Propensity score matching resulted in 32 pairs of patients (closure vs. non-closure 32:32). The primary outcome was post-ESD bleeding. Results: The post-ESD bleeding rate was significantly lower in the closure group (0%) than in the non-closure group (15.6%) (P=0.0264). There were no significant differences between the 2 groups regarding white blood cell count, C-reactive protein, maximum body temperature, or scores on a verbal rating scale that assesses the degree of abdominal pain. Conclusion: Endoscopic closure may contribute to decreasing the incidence of post-ESD gastric bleeding in patients undergoing antithrombotic therapy.

Endoscopic Ligation with O-Ring Closure for Mucosal Defects after Rectal Endoscopic Submucosal Dissection: A Feasibility Study (with Video).

INTRODUCTION: Mucosal defect closure after colorectal endoscopic submucosal dissection (ESD) may prevent post-ESD adverse events. Delayed bleeding is a particular concern in the rectum due to the presence of numerous blood vessels. However, rectal defect closure often fails due to the thick rectal wall. This study aimed to examine the feasibility of our newly developed endoscopic ligation with O-ring closure (E-LOC) for defects after rectal ESD. METHODS: This was a prospective observational study conducted at a single institution. After excluding 2 patients with tumors mostly extending into the anal canal, the study cohort comprised 30 consecutive patients who underwent ESD of rectal neoplasms between July 2020 and July 2021. E-LOC using an endoscopic variceal ligation device was performed for closing mucosal defects after rectal ESD. The primary outcome was the complete closure rate. The secondary outcomes were the delayed bleeding rate, E-LOC procedure time, sustained closure rates on postoperative day (POD) 3, and E-LOC-associated complications. RESULTS: Complete closure of the defect (median defect size 29.0 mm) was successfully achieved in 24 cases (80%). Delayed bleeding occurred in one case with incomplete closure (3.3%). The median E-LOC procedure time was 25.5 min (interquartile range, 20.0-30.0 min). The sustained closure rates were 83.3% (20/24) on POD 3 in the 24 cases with complete closure. No E-LOC-associated complications occurred. DISCUSSION/CONCLUSIONS: E-LOC was feasible for defect closure after rectal ESD, and probably led to a decreased incidence of delayed bleeding.

Comparison of purse-string suture versus over-the-scope clip for gastric endoscopic full-thickness closure: traction and leak pressure testing in ex vivo porcine model.

BACKGROUND: The recently developed endoscopic full-thickness resection technique requires reliable closure. The main closure methods are the purse-string suture (PSS) technique and over-the-scope clip (OTSC) technique; however, basic data on the closure strength of each technique are lacking. This study was performed to compare the closure strengths of these two methods in an ex vivo porcine model. METHODS: In the traction test, a virtual 5-cm full-thickness closure line was closed by the following six methods three times each: conventional hemoclips, mucosal PSS, seromuscular PSS, mucosal OTSC, seromuscular OTSC, and surgical suture. The primary endpoint was the tension at the starting point of dehiscence, measured in Newtons (N) by an automatic traction machine. In the leak test, a 15-mm gastric full-thickness defect was closed by PSS or OTSC six times each, and the closed stomach was then pressurized in a water container. The primary endpoint was the leak pressure when air bubbles appeared. The secondary endpoints were the procedure time and presence of complete inverted closure. RESULTS: The mean tension was 2.16, 3.68, 5.15, 18.30, 19.30, and 62.40 N for conventional hemoclips, mucosal PSS, seromuscular PSS, mucosal OTSC, seromuscular OTSC, and surgical suture, respectively. Complete inverted closure was observed for seromuscular PSS, seromuscular OTSC, and surgical suture. The mean leak pressure was 13.7 and 24.8 mmHg in the PSS and OTSC group, respectively (P < 0.01). The mean procedure time was 541 and 169 s in the PSS and OTSC group, respectively (P < 0.01). Complete inverted closure was observed in OTSC alone. CONCLUSION: The OTSC, which allows complete inverted closure, showed greater closure strength than PSS. Considering the size limitation suitable for single OTSC, a therapeutic strategy for closing the larger size is further warranted.

Clinical and technical outcomes of endoscopic closure of postendoscopic submucosal dissection defects: Literature review over one decade.

Endoscopic submucosal dissection (ESD), which enables curative en bloc resection of early gastrointestinal neoplasms, has been an attractive minimally invasive surgery during the past two decades. Large post-ESD defects must be carefully managed to prevent adverse events (AEs). The major AEs comprise delayed bleeding (DB) and delayed perforation (DP), and overall AEs comprise DB plus DP. This review aimed to clarify the clinical efficacy and technical outcomes of endoscopic prophylactic closure for post-ESD defects. We identified studies involving ≥10 patients up to March 2022 in which endoscopic closure was applied for gastric, duodenal, and colorectal post-ESD defects. In the stomach, total rates of overall AEs and DB were significantly lower in the closure than non-closure group. In the duodenum, total rates of overall AEs, DB, and DP were significantly lower in the closure group. In the colorectum, total rates of overall AEs and DB were significantly lower in the closure group. Closure techniques, categorized into three groups (clip-based techniques, mechanical clipping, and surgical stitch-based techniques), were illustrated. Endoscopic closure demonstrated a certain ability to reduce DB after gastric, duodenal, and colorectal ESD as well as DP after duodenal ESD. Considering closure-associated costs, the indications and limitations of closure techniques should be further investigated.

Acceptability of Hybrid Endoscopic Submucosal Dissection Using Multifunctional Snare for Small-sized Gastric Neoplasms: A Prospective Observational Study.

BACKGROUND AND AIMS: The most suitable procedure for resecting small-sized gastric neoplasms remains unclear. Endoscopic mucosal resection leads to non-curative resection owing to slippage of the snare, and technically difficult endoscopic submucosal dissection (ESD) is instrumentally uneconomical. A novel, cost-effective, multifunctional snare called SOUTEN is available as a hybrid ESD (h-ESD) device developed for facilitating ESD. This study aimed to assess the acceptability of h-ESD using the SOUTEN for resecting small-sized gastric neoplasms. METHODS: This was a prospective observational study conducted at our single institution between March 2019 and March 2021. Fifty-seven consecutive patients who underwent h-ESD using SOUTEN for small-sized gastric neoplasms ≤15 mm involving adenoma and tubular-type mucosal carcinoma without ulceration were enrolled. The primary outcome was curative resection rate for h-ESD. Secondary outcomes were the rates of conversion to ESD, rate of total (h-ESD + ESD) curative resection, procedure time, rates of intra-and post- operative complications, and presence of additional knives excluding hemostatic forceps. RESULTS: The curative resection rate of h-ESD was 89.5% (51/57). The total (h-ESD + ESD) curative resection rate was 94.7% (54/57). The mean procedure time was 21.2 (±16.5) minutes. One case of delayed bleeding occurred. Additional knives were applied in two cases. CONCLUSIONS: The cost-efficient h-ESD using SOUTEN can be an acceptable procedure for resecting small- sized gastric neoplasms.

Beige mucosa observable under narrow-band imaging indicates the active sites of eosinophilic esophagitis.

BACKGROUND AND AIM: The majority of patients with eosinophilic esophagitis (EoE) are likely to have observable features under narrow-band imaging, namely beige mucosa. However, the histological features and clinical implications of beige mucosa have not been investigated. The aim of this study was to determine whether beige mucosa could serve as an endoscopic marker for predicting active inflammatory sites of EoE. METHODS: We retrospectively analyzed both the narrow-band images and biopsied specimens of 77 esophageal lesions from 35 consecutive patients with EoE. We divided these specimens into two groups: target biopsied specimens from beige mucosa (beige group) and specimens biopsied from non-beige mucosa (non-beige group). The number of eosinophils per high-powered field, thickness of the superficial differentiated cell layer, and depth of the hemoglobin component from the surface layer were compared between the two groups. RESULTS: Forty-four out of the 45 specimens were diagnosed as histological active lesions in the beige group. The sensitivity, specificity, and overall accuracy of beige mucosa in predicting EoE activity were 97.8%, 96.9%, and 97.8%, respectively. Compared with the non-beige group, specimens in the beige group had a significantly thinner superficial differentiated cell layer. CONCLUSIONS: Beige mucosa is associated with thinning of the normal superficial differentiated cell layer, and these histological changes in the active inflammatory sites of EoE could be recognized endoscopically as color differences. Beige mucosa may serve as an endoscopic indicator for predicting the histological activity of EoE.

Efficacy of endoscopic ligation with O-ring closure for prevention of bleeding after gastric endoscopic submucosal dissection under antithrombotic therapy: a prospective observational study.

BACKGROUND: We examined the efficacy of a novel endoscopic ligation technique with O-ring closure (E-LOC) to prevent bleeding after gastric endoscopic submucosal dissection (ESD) under antithrombotic therapy. METHODS: This single-center prospective study involved consecutive patients who were taking antithrombotic agents and underwent gastric ESD. E-LOC was performed by anchoring the nylon loop with hemoclips on both defect edges and/or the exposed muscle layer, and using O-ring band ligation around these deployed clips. The primary outcome was post-ESD bleeding rate. Secondary outcomes were complete closure rate, procedure time, sustained closure rate, and complications. RESULTS: 48 patients were finally analyzed. The post-ESD bleeding rate was 0 %, the complete closure rate was 97.9 %, and the mean closure time was 29.9 minutes. The sustained closure rate was 95.8 % at postoperative day 2-3 and 33.3 % at postoperative day 10-11. No complications occurred. CONCLUSION: E-LOC may be an effective option for closing mucosal defects after gastric ESD under antithrombotic therapy. However, the preventive effect on post-ESD bleeding should be further investigated in high risk groups.