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.

Texture and color enhancement imaging improves the visibility of gastric neoplasms: clinical trial with image catalogue assessment using conventional and newly developed endoscopes.

BACKGROUND: Texture and color enhancement imaging (TXI) enhances the changes in endoscopic features caused by gastric neoplasms, such as redness/whiteness and elevation/depression. This study aimed to demonstrate the effectiveness of TXI in improving the visibility of gastric neoplasms compared with white light imaging (WLI) using conventional (CE) and newly developed endoscopes (NE). METHODS: We recruited patients who were histologically diagnosed with gastric neoplasms; endoscopy was performed, and gastric neoplasms photographed using three imaging modalities, including WLI, TXI mode 1 (TXI-1) and TXI mode 2 (TXI-2). Two different endoscopes (CE and NE) were used for the same patients. Six endoscopists provided the visibility scale scores ranging from 1 (poor) to 4 (excellent) for gastric neoplasms. The primary outcome was the visibility scale scores based on each modality and endoscope. The secondary outcome was the identification of factors including H. pylori infection, atrophy, location, size, morphology, histological diagnosis and intestinal metaplasia that affect the differences in visibility scale scores between TXI-1/TXI-2 and WLI. RESULTS: Fifty-two gastric neoplasms were analyzed. The mean visibility scale scores with the NE were 2.79 ± 1.07, 3.23 ± 0.96 and 3.14 ± 0.92 for WLI, TXI-1 and TXI-2, respectively. The mean visibility scales with the CE were 2.53 ± 1.10, 3.04 ± 1.05 and 2.96 ± 1.92 for WLI, TXI-1 and TXI-2, respectively. For both endoscopes, significant differences were observed in visibility scale scores between WLI and TXI-1 (p < 0.001) and between WLI and TXI-2 (p < 0.001). The visibility scale scores of NE were superior to those of CE in all modalities. In the secondary outcome, there was no factor affected the differences of visibility scale scores between TXI-1/TXI-2 and WLI. CONCLUSIONS: This study demonstrated that TXI-1 and TXI-2 enhanced the visibility scale scores of gastric neoplasms compared with that of WLI. Moreover, newly developed endoscope has the potential to improve visibility compared to conventional endoscope. TRIAL REGISTRATION: This study was registered with the University Hospital Medical Information Network (UMIN000042429, 16/11/2020).

Endoscopic full-thickness resection for gastric submucosal tumors: Japanese multicenter prospective study.

OBJECTIVES: Early gastric cancer endoscopic resection (ER) is prominent in Japan. However, evidence regarding ER of gastric submucosal tumors (SMT) is limited. This prospective multicenter phase II study investigated the efficacy and safety of endoscopic full-thickness resection (EFTR) for gastric SMT. METHODS: Endoscopic full-thickness resection indication for gastric SMT was 11-30 mm, histologically proven or clinically suspicious (irregular margin, increasing size, or internal heterogeneity) gastrointestinal stromal tumors (GIST), with no ulceration and intraluminal growth type. The primary end-point was the complete ER (ER0) rate, with a sample size of 42. RESULTS: We enrolled 46 patients with 46 lesions between September 2020 and May 2023 at seven Japanese institutions. The mean ± SD (range) endoscopic tumor size was 18.8 ± 4.5 (11-28) mm. The tumor resection and defect closure times were 54 ± 26 (22-125) min and 33 ± 28 (12-186) min, respectively. A 100% ER0 was achieved in all 46 patients. The EFTR procedure was accomplished in all patients without surgical intervention. One patient had delayed perforation and was managed endoscopically. GIST accounted for 76% (n = 35) of the cases. R0, R1, and RX rates were 33 (77%), 3 (6.5%), and 7 (15%), respectively. CONCLUSION: Endoscopic full-thickness resection for gastric SMT of 11-30 mm is efficacious. It warrants further validation in a large-scale cohort study to determine the long-term outcome of this treatment for patients with gastric GIST.

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.

Sarcopenia Is a Prognostic Factor in Patients Undergoing Percutaneous Endoscopic Gastrostomy.

(1) Background: Percutaneous endoscopic gastrostomy (PEG) is a widely used long-term enteral nutrition method, but little is known about the associated prognostic factors in patients with PEG. Sarcopenia, a condition characterized by a loss of skeletal muscle mass, increases the risk of developing various gastrointestinal disorders. Yet, the relationship between sarcopenia and the prognosis after PEG remains unclear. (2) Methods: We conducted a retrospective study of patients who underwent PEG consecutively from March 2008 to April 2020. We analyzed preoperative sarcopenia and the prognosis of patients after PEG. We defined sarcopenia as a skeletal muscle index at the level of the third lumbar vertebra of ≤29.6 cm2/m2 for women and ≤36.2 cm2/m2 for men. Cross-sectional computed tomography images of skeletal muscle at the level of the third lumbar vertebra were evaluated using DICOM image analysis software (OsiriX). The primary outcome was the difference in overall survival after PEG based on the status of sarcopenia. We also performed a covariate balancing propensity score matching analysis. (3) Results: Of 127 patients (99 men, 28 women), 71 (56%) were diagnosed with sarcopenia, and 64 patients died during the observation period. The median follow-up period did not differ between patients with and without sarcopenia (p = 0.5). The median survival time after PEG was 273 days in patients with sarcopenia and 1133 days in those without (p < 0.001). Cox proportional hazard model analyses identified three factors that were significantly associated with overall survival: sarcopenia (adjusted hazard ratio [HR]: 2.9, 95% confidence interval [CI]: 1.6-5.4, p < 0.001), serum albumin level (adjusted HR: 0.34, 95% CI: 0.21-0.55, p < 0.001) and male sex (adjusted HR: 2.0, 95% CI: 1.1-3.7, p = 0.03). Propensity score-matched analysis (n = 37 vs. 37) showed that the survival rate was lower in the sarcopenia group than in the non-sarcopenia group (at 90 days: 77% (95% CI, 59-88) vs. 92% (76-97), at 180 days: 56% (38-71) vs. 92% (76-97), and at one year: 35% (19-51) vs. 81% (63-91), p = 0.0014). (4) Conclusions: Sarcopenia was associated with poor prognosis in patients having undergone PEG.

Lymph node metastasis after endoscopic submucosal dissection of a superficial esophageal adenocarcinoma arising from the ectopic gastric mucosa of the cervical esophagus: A case report.

Esophageal adenocarcinoma derived from the ectopic gastric mucosa of the cervical esophagus is very rare. Little is known about the efficacy of endoscopic treatment of these superficial lesions. Herein, we report the first case of lymph node metastasis after endoscopic submucosal dissection of a lesion with invasion into the muscularis mucosa. A 46-year-old man underwent esophagogastroduodenoscopy during a health checkup. Endoscopy revealed a 10-mm-sized nodular and a 5-mm-sized depressed lesion within the ectopic gastric mucosa of the cervical esophagus. The biopsy specimen confirmed the presence of adenocarcinoma. The entire ectopic gastric mucosa was resected by endoscopic submucosal dissection, and pathological examination showed invasion of the muscularis mucosa. A follow-up computed tomography scan revealed lymph node metastasis 12 months post-treatment. The patient underwent surgical mediastinal lymphadenectomy. The patient has been regularly followed up with a computed tomography scan and endoscopy for 2 years post-surgery with no evidence of recurrence. Close follow-up or additional treatment after endoscopic submucosal dissection should be considered and discussed with the patient if invasion into the muscularis mucosa is observed on pathological examination.

Detection of colorectal adenomas with texture and color enhancement imaging: Multicenter observational study.

OBJECTIVES: We aimed to evaluate the efficacy of texture and color enhancement imaging (TXI), which allows the acquisition of brighter images with enhanced color and surface structure in colorectal polyp detection compared to white light imaging. METHODS: Patients who underwent colonoscopy with repeated ascending colon observation using TXI and white light imaging between August 2020 and January 2021 were identified in three institutions. The outcomes included the mean number of adenomas detected per procedure (MAP), adenoma detection rate (ADR), and ascending colonic adenoma miss rate (Ac-AMR). Logistic regression was used to determine the effects of the variables on the outcomes. RESULTS: We included 1043 lesions from 470 patients in the analysis. The MAP, ADR, flat polyp detection rate, and Ac-AMR in TXI and white light imaging were 1.5% (95% confidence interval 1.3-1.6%) vs. 1.0% (0.9-1.1%), 58.2% (51.7-64.6%) vs. 46.8% (40.2-53.4%), 66.2% (59.8-72.2%) vs. 49.8% (43.2-56.4%), and 17.9% (12.1-25.2%) vs. 28.2% (20.0-37.6%), respectively. TXI, age, withdrawal time, and endoscopy type were identified as significant factors affecting the MAP and the ADR using multivariate regression analysis. CONCLUSIONS: Our study indicates that TXI improve the detection of colorectal neoplastic lesions. However, prospective randomized trials are required to confirm these findings.

Impact of Artificial Intelligence on Colonoscopy Surveillance After Polyp Removal: A Pooled Analysis of Randomized Trials.

BACKGROUND AND AIMS: Artificial intelligence (AI) tools aimed at improving polyp detection have been shown to increase the adenoma detection rate during colonoscopy. However, it is unknown how increased polyp detection rates by AI affect the burden of patient surveillance after polyp removal. METHODS: We conducted a pooled analysis of 9 randomized controlled trials (5 in China, 2 in Italy, 1 in Japan, and 1 in the United States) comparing colonoscopy with or without AI detection aids. The primary outcome was the proportion of patients recommended to undergo intensive surveillance (ie, 3-year interval). We analyzed intervals for AI and non-AI colonoscopies for the U.S. and European recommendations separately. We estimated proportions by calculating relative risks using the Mantel-Haenszel method. RESULTS: A total of 5796 patients (51% male, mean 53 years of age) were included; 2894 underwent AI-assisted colonoscopy and 2902 non-AI colonoscopy. When following U.S. guidelines, the proportion of patients recommended intensive surveillance increased from 8.4% (95% CI, 7.4%-9.5%) in the non-AI group to 11.3% (95% CI, 10.2%-12.6%) in the AI group (absolute difference, 2.9% [95% CI, 1.4%-4.4%]; risk ratio, 1.35 [95% CI, 1.16-1.57]). When following European guidelines, it increased from 6.1% (95% CI, 5.3%-7.0%) to 7.4% (95% CI, 6.5%-8.4%) (absolute difference, 1.3% [95% CI, 0.01%-2.6%]; risk ratio, 1.22 [95% CI, 1.01-1.47]). CONCLUSIONS: The use of AI during colonoscopy increased the proportion of patients requiring intensive colonoscopy surveillance by approximately 35% in the United States and 20% in Europe (absolute increases of 2.9% and 1.3%, respectively). While this may contribute to improved cancer prevention, it significantly adds patient burden and healthcare costs.

Analysis of the variation in learning curves for achieving competency in convex EUS training: a prospective cohort study using a standardized assessment tool.

BACKGROUND AND AIMS: The need for mastering standard imaging techniques for convex EUS in the biliopancreatic regions has been increasing; however, large variations in the aptitude for achieving EUS competency hinder expert development. Therefore, we investigated the factors influencing the achievement of expert competency in EUS using a new assessment tool for multiple imaging items. METHODS: Between January 2018 and February 2022, 3277 consecutive EUS procedures conducted by 5 beginners (EUS procedures <250), 7 intermediate trainees (250-749), and 2 experts (≥750) were prospectively evaluated. Immediately after each EUS procedure, the success or failure of imaging for each item was recorded using a newly developed EUS assessment tool that requires 17 items to be photographed. After correcting for missing values using multiple imputation, learning curves of EUS scores were created, and a competency was set based on expert scores. Finally, a comparative analysis between high and low performers was performed to extract factors influencing EUS scores. RESULTS: Although 3 of 7 intermediates (43%; mean, 317 cases) achieved competency, none of the beginners achieved competency. During a comparative analysis, although no significant difference in the number of EUS procedures performed was observed between the high and low performers, the former had significantly higher scores in the written test (theoretical knowledge). CONCLUSIONS: Our results showed that theoretical knowledge, rather than the number of EUS cases, may be a possible influencing factor for distinguishing high and low performers after treating 250 cases. (Clinical trial registration number: UMIN 000043271.).

Potential significance of uncovered self-expandable metal stents for distal malignant biliary obstruction: A propensity score-adjusted competing risk regression analysis.

Objectives: Selection criteria for self-expandable metal stents (SEMSs) with or without cover during palliative treatment of distal malignant biliary obstruction (DMBO) remain unclear. We evaluated factors associated with time to recurrent biliary obstruction (TRBO) in fully covered SEMSs (FCSEMSs) and uncovered SEMSs (UCSEMSs). Methods: We retrospectively analyzed consecutive patients with DMBO who received a SEMS. TRBO was determined using the Kaplan-Meier analysis, and complications were compared between the FCSEMS and UCSEMS groups. After TRBO-associated factors were extracted using multivariate competing-risks regression (CRR), propensity score-adjusted CRRs were performed to verify their robustness. Results: There were 180 patients (66 FCSEMSs and 114 UCSEMSs) enrolled in this study. There was no significant difference between median TRBO in the FCSEMS and UCSEMS groups (275 vs. 255 days, p = 0.67). Complications were more frequent in the FCSEMS than UCSEMS group (21.2% vs. 8.8%; p = 0.023). Multivariate CRR for TRBO-associated factors revealed that "pancreatic ductal carcinoma (PDAC) treated with UCSEMS" was the only independent predictor of TRBO (p = 0.03). Similarly, the propensity score-adjusted CRRs showed no significant difference in TRBO in "FCSEMS" vs "UCSEMS" (p = 0.96); however, there was a significant difference in "PDAC using UCSEMS" vs "other" (p = 0.043). In the palliative care group including any DMBO without chemotherapy, the first quartile of the TRBO of UCSEMS was 100 days. Conclusions: UCSEMSs are a possible option for both patients with DMBO arising from PDAC and for patients with any DMBO receiving palliative care who should avoid SEMS-related complications.

The Advantage of Immunohistochemical Staining for Evaluating Lymphovascular Invasion Is Limited for Patients with Esophageal Squamous Cell Carcinoma Invading the Muscularis Mucosa.

The cumulative metastasis rate of esophageal squamous cell carcinoma (ESCC) pathologically invading the muscularis mucosae (pT1a-MM), based on lymphovascular invasion (LVI) evaluated by immunohistochemical (IHC) staining is unknown. This retrospective study included patients with endoscopically resected pT1a-MM ESCC. The primary endpoint was the metastasis rate of pT1a-MM based on LVI, evaluated using IHC and additional prophylactic therapy. The secondary endpoint was the identification of independent factors for metastasis based on lesion characteristics. The prognosis was also analyzed considering the impact of head and neck cancer. A total of 104 patients were analyzed, with a median follow-up of 74 months. The positive rate for LVI was 43.3% (45/104). In 33 patients, IHC was not performed at the time of clinical evaluation, 8 of whom exhibited LVI. However, these patients did not exhibit metastasis. The metastasis rates of patients without LVI, those with LVI and additional therapy, and those with LVI without additional therapy were 5.1%, 20.8%, and 0%, respectively. Lesion size ≥ 25 mm was the only independent factor for metastasis in multivariate analysis. The advantage of IHC for determining additional prophylactic therapy is limited for patients with pT1a-MM ESCC.

Diagnostic Dilemma of Biliopancreatic Contrast-Enhanced Harmonic Endoscopic Ultrasonography.

Background: The utility of contrast-enhanced harmonic endoscopic ultrasonography (CH-EUS) alone in the biliopancreatic region appears to be limited because it is highly dependent on the experience and skill of the endoscopist. Therefore, the present study aimed to validate the efficacy of CH-EUS in clinical practice. Methods: Between January 2018 and March 2019, 301 consecutive patients who underwent CH-EUS were prospectively enrolled in this study. The diagnostic performance of CH-EUS was compared with that of dynamic computed tomography (CT), magnetic resonance imaging (MRI), and all combinations (i.e., CH-EUS, dynamic CT, and MRI) using a Bonferroni correction. A multiple logistic regression analysis was performed to extract each disease that allowed the CH-EUS diagnosis to be consistent with the final diagnosis. Results: In multiple comparisons of diagnostic performance, no significant differences were observed among dynamic CT, MRI, and CH-EUS (p = 1.00), but the diagnostic performance was significantly higher when all modalities were combined (p < 0.001). Moreover, only intraductal papillary mucinous neoplasm comprising adenoma or carcinoma (IPMN, n = 161) showed significance with respect to the agreement with the final diagnosis (p = 0.006). Conclusions: Our results showed that CH-EUS-based diagnosis of IPMN may be possible in clinical practice. On the contrary, to accurately diagnose biliopancreatic diseases other than IPMN, comprehensive diagnosis using multiple modalities may be necessary, rather than relying on CH-EUS alone.

Proposal of minimum elements for screening and diagnosis of gastric cancer by an international Delphi consensus.

The World Endoscopy Organization Stomach and Duodenal Diseases Committee extracted minimum elements for screening and diagnosis of gastric cancer (GC) in aim to support countries that do not have national guidelines on screening and diagnosis of GC. Current national or international guidelines were collected worldwide and recommendations were classified according to the quality of evidence and were finalized through a modified Delphi method. The minimum elements consist of seven categories: [1] Extraction of high-risk patients of GC before esophagogastroduodenoscopy (EGD), [2] Patients who need surveillance of GC, [3] Method to ensure quality of EGD for detection of GC, [4] Individual GC risk assessment by EGD, [5] Extraction of high-risk patients of GC after EGD [6] Qualitative or differential diagnosis of GC by EGD, and [7] Endoscopic assessment to choose the therapeutic strategy for GC. These minimum elements will be a guide to promote the elimination of GC among countries with a high incidence of GC who lack national guidelines or screening programs.

International remote collaboration enabled inaugural endoscopic sleeve gastroplasty in Japan.

Obesity causes multiple conditions such as type 2 diabetes, cardiovascular disease, and so on, and an intervention is needed for controlling weight and improving metabolic syndrome. However, the effectiveness of lifestyle interventions and pharmacotherapy are restrictive for losing weight. Endoscopic sleeve gastroplasty (ESG) was developed as a new therapy, picking the best of both medication and surgery, less invasive and more effective. Recently, ESG is gradually spreading in Western countries, but there is Case report doesn't need conclusion/result for Japanese patients. We herein reported the first clinical case of ESG in Japan. Given the situation of the pandemic of COVID-19, we could not invite a proctor from Western countries and receive the instruction of the device setting and maneuver face to face. Thus, we conducted the training for device setting, maneuver, and operation under a web-based international remote collaboration. Eventually, we completed ESG without an adverse event. We could prove this web-based proctor system was useful through the introduction of ESG in Japan. The international remote collaboration could become a new normal even in the endoscopy field post-COVID-19 era.