Endoscopic mucosal resection and endoscopic submucosal dissection

Robotic wireless capsule endoscopy: recent advances and upcoming technologies

Wireless capsule endoscopy (WCE) offers a non-invasive evaluation of the digestive system, eliminating the need for sedation and the risks associated with conventional endoscopic procedures. Its significance lies in diagnosing gastrointestinal tissue irregularities, especially in the small intestine. However, existing commercial WCE devices face limitations, such as the absence of autonomous lesion detection and treatment capabilities. Recent advancements in micro-electromechanical fabrication and computational methods have led to extensive research in sophisticated technology integration into commercial capsule endoscopes, intending to supersede wired endoscopes. This Review discusses the future requirements for intelligent capsule robots, providing a comparative evaluation of various methods' merits and disadvantages, and highlighting recent developments in six technologies relevant to WCE. These include near-field wireless power transmission, magnetic field active drive, ultra-wideband/intrabody communication, hybrid localization, AI-based autonomous lesion detection, and magnetic-controlled diagnosis and treatment. Moreover, we explore the feasibility for future "capsule surgeons".

Efficacy and Safety of Thermal Ablation after Endoscopic Mucosal Resection: A Systematic Review and Network Meta-Analysis

(1) Background: Large colonic polyps during colonoscopy can be managed by Endoscopic mucosal resection (EMR). To decrease the polyp recurrence rate, thermal ablation methods like argon plasma coagulation (APC) and snare tip soft coagulation (STSC) have been introduced. We performed this network meta-analysis to assess the efficacy and safety of these modalities. (2) Methods: We performed a comprehensive literature review, through 5 January 2024, of databases including Embase, PubMed, SciELO, KCI, Cochrane Central, and Web of Science. Using a random effects model, we conducted a frequentist approach network meta-analysis. The risk ratio (RR) with 95% confidence interval (CI) was calculated. Safety and efficacy endpoints including rates of recurrence, bleeding, perforation, and post polypectomy syndrome were compared. (3) Results: Our search yielded a total of 13 studies with 2686 patients. Compared to placebo, both APC (RR: 0.33 CI: 0.20-0.54, p < 0.01) and STSC (RR: 0.27, CI: 0.21-0.34, p < 0.01) showed decreased recurrence rates. On ranking, STSC showed the lowest recurrence rate, followed by APC and placebo. Regarding individual adverse events, there was no statistically significant difference between either of the thermal ablation methods and placebo. (4) Conclusions: We demonstrated the efficacy and safety of thermal ablation after EMR for decreasing recurrence of adenoma.

Nanodrugs systems for therapy and diagnosis of esophageal cancer

With the increasing incidence of esophageal cancer, its diagnosis and treatment have become one of the key issues in medical research today. However, the current diagnostic and treatment methods face many unresolved issues, such as low accuracy of early diagnosis, painful treatment process for patients, and high recurrence rate after recovery. Therefore, new methods for the diagnosis and treatment of esophageal cancer need to be further explored, and the rapid development of nanomaterials has brought new ideas for solving this problem. Nanomaterials used as drugs or drug delivery systems possess several advantages, such as high drug capacity, adjustably specific targeting capability, and stable structure, which endow nanomaterials great application potential in cancer therapy. However, even though the nanomaterials have been widely used in cancer therapy, there are still few reviews on their application in esophageal cancer, and systematical overview and analysis are deficient. Herein, we overviewed the application of nanodrug systems in therapy and diagnosis of esophageal cancer and summarized some representative case of their application in diagnosis, chemotherapy, targeted drug, radiotherapy, immunity, surgery and new therapeutic method of esophageal cancer. In addition, the nanomaterials used for therapy of esophageal cancer complications, esophageal stenosis or obstruction and oesophagitis, are also listed here. Finally, the challenge and the future of nanomaterials used in cancer therapy were discussed.

Unlocking quality in endoscopic mucosal resection

A review of the development of the key performance metrics of endoscopic mucosal resection (EMR), learning from the experience of the establishment of widespread colonoscopy quality measurements. Potential future performance markers for both colonoscopy and EMR are also evaluated to ensure continued high quality performance is maintained with a focus service framework and predictors of patient outcome.

Global research trends of endoscope in early gastric cancer: A bibliometric and visualized analysis study over past 20 years

Objectives

Early gastric cancer (EGC) is defined as aggressive gastric cancer involving the gastric mucosa and submucosa. Early detection and treatment of gastric cancer are beneficial to patients. In recent years, many studies have focused on endoscopic diagnosis and therapy for EGC. Exploring new methods to analyze data to enhance knowledge is a worthwhile endeavor, especially when numerous studies exist. This study aims to investigate research trends in endoscopy for EGC over the past 20 years using bibliometric analysis.

Methods

Original articles and reviews examining the use of endoscopy for EGC published from 2000 to 2022 were retrieved from the Web of Science Core Collection, and bibliometric data were extracted. Microsoft Office Excel 2016 was used to show the annual number of published papers for the top 10 countries and specific topics. VOSviewer software was used to generate network maps of the cooccurrences of keywords, authors, and topics to perform visualization network analysis.

Results

In total, 1,009 published papers met the inclusion criteria. Japan was the most productive country and had the highest number of publications (452, 44.8%), followed by South Korea (183, 18.1%), and China (150, 14.9%). The National Cancer Center of Japan was the institution with the highest number of publications (48, 4.8%). Ono was the most active author and had the highest number of cited publications. Through the network maps, exploring endoscopic diagnosis and therapy were major topics. Artificial intelligence (AI), convolutional neural networks (CNNs), and deep learning are hotspots in endoscopic diagnosis. Helicobacter pylori eradication, second-look endoscopy, and follow-up management were examined.

Conclusions

This bibliometric analysis investigated research trends regarding the use of endoscopy for treating EGC over the past 20 years. AI and deep learning, second-look endoscopy, and management are hotspots in endoscopic diagnosis and endoscopic therapy in the future.

Learning curve of endoscopic submucosal dissection (ESD) with prevalence-based indication in unsupervised Western settings: a retrospective multicenter analysis

BACKGROUND AND AIMS

As there is still no consensus about the adequate training strategy for ESD in Western countries, we evaluated unsupervised prevalence-based learning curves including detailed organ-specific subgroup analysis.

METHODS

The first 120 ESDs of four operators (n = 480) were divided into three groups (1: ESD 1-40, 2: ESD 41-80, 3: ESD 81-120). Outcome parameters were rates of technical success, en bloc and R0 resection, the resection speed, rates of conversion to EMR, curative resection, adverse events, surgery due to adverse events, and recurrence. In addition, we analyzed the achievement of quality benchmarks indicating levels of expertise.

RESULTS

After exclusion of pretreated lesions, 438 procedures were enrolled in the final analysis. Technical success rates were > 96% with significant improvements regarding rate of en bloc resection (from 82.6 to 91.2%), resection speed (from 4.54 to 7.63 cm²/h), and rate of conversion to EMR (from 22.0 to 8.1%). No significant differences could be observed for rates of R0 resection (65.9 vs. 69.6%), curative resection (55.8 vs. 55.7%), adverse events (16.3 vs. 11.7%), surgery due to adverse events (1.5 vs. 1.3%), and recurrence (12.5 vs. 4.5%). Subgroup and benchmark analysis revealed an improvement in esophageal, gastric, and rectal ESD with achievement of competence levels for the esophagus and stomach within 80 and most of the benchmarks for proficiency level within 120 procedures. Some of the benchmarks could also be achieved in rectal ESD.

CONCLUSIONS

This trial confirms safety and feasibility of unsupervised ESD along the initial learning curve with prevalence-based indication and exclusion of colonic cases.

Early colorectal cancer diagnosed after endoscopic resection: Conservative treatment is safe in most of the cases. Proposal for a risk-based management

INTRODUCTION

Endoscopic resection offers advantages over surgical resection for early colorectal cancer (ECC). However, there might be a presumed risk of recurrence. We aimed to determine the risk of recurrence after endoscopic removal of ECC.

METHODS

A single-centre series of endoscopic resections for ECC. Patients were stratified according to four risk factors: positive resection margins, Haggitt 4, lymphatic/vascular invasion and tumour budding.

RESULTS

We included 127 patients. Haggitt classification was grade 4 in 54.0%. Positive margins were found in 43 (33.9%), 16 (12.6%) had lymphatic or vascular invasion, and 5 (4.0%) had high grade budding. In 82 (64.5%) endoscopic excision was the definitive treatment, 45 (35.4%) underwent surgery. Six patients (13.3%) had residual tumour on specimen and/or node metastases. Postoperative complications occurred in ten (22.2%). At a median follow-up of 63 months, none of the 82 patients treated with endoscopic resection alone had recurrence. After stratifying patients according to risk factors, those who had residual tumour also had ≥2 risk factors.

CONCLUSIONS

Endoscopic follow up might be a valid option for patients with ECC. A risk-adjusted management seems prudent.

The 8th Wonder of the Cancer World: Esophageal Cancer and Inflammation

Esophageal cancer is a devastating malignancy which can be detected at an early stage but is more often diagnosed as an advanced process. It affects both men and women and inflicts the young and the elderly. There are multiple underlying factors involved in the pathogenesis of this cancer including inflammation. The interplay of these factors promotes inflammation through various mechanisms including the recruitment of pro-inflammatory cells, mediators such as cytokines, reactive oxygen species, and interleukins, among others. The presentation can vary widely with one of the most notable symptoms being dysphagia. Diagnosis is based on clinical symptomatology, imaging and endoscopy with biopsy. Once the diagnosis has been established, treatment and prognosis are based on the stage of the disease. This review outlines esophageal cancer and its link to inflammation in relation to pathogenesis, along with clinical features, diagnosis and treatment.

Advances in endoscopic resection: a review of endoscopic submucosal dissection (ESD), endoscopic full thickness resection (EFTR) and submucosal tunneling endoscopic resection (STER)

Subepithelial lesions are often detected incidentally in patients undergoing an endoscopy. They are common tumors of the gastrointestinal (GI) tract which can originate from different layers of the GI tract wall. These lesions can be further classified based on GI layer of origin and unique histochemical staining. While most are benign and asymptomatic, some of these lesions have malignant potential with distant metastases. However, current diagnostic modalities including endoscopy with biopsy or endoscopic ultrasound with fine needle aspiration are not always reliable. In addition, management of these lesions has historically involved surgical resection via open or laparoscopic approaches. In recent years, with advancement in endoscopic techniques and improvement in endoscopists' skills, less invasive procedures such as endoscopic submucosal dissection (ESD), endoscopic full thickness resection (EFTR) and submucosal tunneling endoscopic resection (STER) have been developed and now are being used by endoscopists worldwide. Upon reviewing the literature, multiple studies have shown the advantages of these endoscopic techniques when compared with surgical treatment. As a result, there has been a dramatic shift towards minimally invasive endoscopic procedures for the management of these subepithelial lesions. In this review article, we will discuss these endoscopic resection techniques in detail, their safety and efficacy, as well as comparison studies to other therapeutic modalities.

Advances in gastrointestinal surgical endoscopy

Surgeons have a role in observing, detect abnormalities, disease, and other deficiencies in function which could be treated. Diagnosing and treating back days were challenging for many reasons. However, technology's innovation enhances surgeons' ability to treat their patients. The term endoscopy refers to the Greek prefix endo- ("within") and the verb skopein ("to view or observe"). Endoscopy is practical both in the diagnosis and treatment of various pathologies. Technological advances, especially in endoscopy, gradually progress and discover many possibilities which allow rapid advancement. Endoscopy development aims to assess human orifice that has not been inspected, probed, and examined over the centuries. Endoscopy over these decades is improving, which led to new problem solving using advanced technological approaches. Thus, a surgeon can solve any issues from examination, diagnosis, and treatment using progressive endoscopy evolution. This review delivers a brief history of advances in surgical endoscopy and describes current endoscopy development.

Modified endoscopic mucosal resection techniques for treating precancerous colorectal lesions

Endoscopic mucosal resection (EMR) is a technique allowing efficacious and minimally invasive resection of precancerous lesions across the entire gastrointestinal tract. However, conventional EMR, involving injection of fluid into the submucosal space, is imperfect, given the high rate of recurrence of post-endoscopic resection adenoma, especially after piecemeal resection. In light of these observations, modifications of the technique have been proposed to overcome the weakness of conventional EMR. Some of them were designed to maximize the chance of en bloc resection—cap-assisted EMR, underwater EMR, tip-in EMR, precutting, assisted by ligation device—while others were designed to minimize the complications (cold EMR). In this review, we present their modes of action and summarize the evidence regarding their efficacy and safety.

Role of hospitalization for inflammatory bowel disease in the post-biologic era

Treatment for inflammatory bowel disease (IBD) often requires specialized care. While much of IBD care has shifted to the outpatient setting, hospitalizations remain a major site of healthcare utilization and a sizable proportion of patients with inflammatory bowel disease require hospitalization or surgery during their lifetime. In this review, we approach IBD care from the population-level with a specific focus on hospitalization for IBD, including the shifts from inpatient to outpatient care, the balance of emergency and elective hospitalizations, regionalization of specialty IBD care, and contribution of surgery and endoscopy to hospitalized care.

Efficacy of Sodium Carboxymethylcellulose Compared to Sodium Hyaluronate as Submucosal Injectant for Gastric Endoscopic Submucosal Dissection: A Randomized Controlled Trial

INTRODUCTION

Sodium hyaluronate (SH) is a useful submucosal injectant for gastric endoscopic submucosal dissection (ESD). On the other hand, sodium carboxymethylcellulose (SCMC), which has high viscosity, has also been applied clinically. We evaluated the efficacy of SCMC compared to that of SH in gastric ESD.

METHODS

A prospective randomized controlled trial was conducted to assess the efficacy of 1.0% SCMC as the injectant (SCMC group) compared to 0.4% SH (SH group) for ESD of gastric neoplasms. The primary end point was the procedure time of ESD. Secondary end points were treatment outcomes such as en bloc and R0 resection rates, number of hemostases, amount of injectant, ease of treatment (visual analog scale, 1-10 points), adverse events, and rate of ulcer healing 8 weeks after ESD.

RESULTS

A total of 60 patients were enrolled between October 2014 and October 2018, and 30 patients were allocated in each group. The procedure time (mean ± SD, minutes) was not significantly different between the SCMC (74.7 ± 54.5) and SH groups (67.1 ± 41.4) (p = 0.547). Furthermore, there were no differences between the 2 groups in terms of en bloc and R0 resection rates, number of hemostases, amount of injectant, ease of treatment, and rate of ulcer healing. No serious adverse events were observed in either group.

CONCLUSION

SCMC was comparable to SH in terms of procedure time, treatment outcome, and ease and safety of treatment in gastric ESD. Further studies are needed to demonstrate the differences between the 2 injectants.

Risk stratification of patients with gastric lesions indefinite for dysplasia

BACKGROUND/AIMS

There are no definite guidelines for the management of gastric lesions diagnosed as indefinite for dysplasia (IND) by endoscopic forceps biopsy (EFB). Therefore, this study aimed to evaluate the clinical outcomes of gastric IND and predictive factors for gastric neoplasm.

METHODS

This study included 457 patients with a first diagnosis of gastric IND by EFB between January 2005 and December 2013. Patient characteristics and endoscopic and pathological data were reviewed and compared.

RESULTS

Of the 457 gastric IND patients, 128 (28%) were diagnosed with invasive carcinoma, 21 (4.6%) with high-grade dysplasia, 31 (6.8%) with low-grade dysplasia, and 277 (60.6%) as negative for dysplasia. Of lesions observed, 180 (39.4%) showed upgraded histology. Multivariate analysis revealed that surface erythema (odds ratio [OR], 2.804; 95% confidence interval [CI], 1.741 to 4.516), spontaneous bleeding (OR, 2.618; 95% CI, 1.298 to 5.279), lesion size ≥ 1 cm (OR, 5.762; 95% CI, 3.459 to 9.597), and depressed morphology (OR, 2.183; 95% CI, 1.155 to 4.124) were significant risk factors for high-grade dysplasia or adenocarcinoma. The ORs associated with 2 and ≥ 3 risk factors were 7.131 and 34.86, respectively.

CONCLUSION

Precautions should be taken in the management of gastric IND patients, especially when risk factors, including surface erythema, spontaneous bleeding, lesion size ≥ 1 cm, and depressed morphology are present. Considering the combined effect of the presence of multiple risk factors on the incidence of high-grade dysplasia or adenocarcinoma, endoscopic resection should be recommended if a gastric IND patient has at two or more of these factors.

Indications and outcomes of endoscopic resection for non-pedunculated colorectal lesions: A narrative review

In the last years, endoscopic techniques gained a crucial role in the treatment of colorectal flat lesions. At the same time, the importance of a reliable assessment of such lesions to predict the malignancy and the depth of invasion of the colonic wall emerged. The current unsolved dilemma about the endoscopic excision techniques concerns the necessity of a reliable submucosal invasive cancer assessment system that can stratify the risk of the post-procedural need for surgery. Accordingly, this narrative literature review aims to compare the available diagnostic strategies in predicting malignancy and to give a guide about the best techniques to employ. We performed a literature search using electronic databases (MEDLINE/PubMed, EMBASE, and Cochrane Library). We collected all articles about endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) registering the outcomes. Moreover, we analyzed all meta-analyses comparing EMR vs ESD outcomes for colorectal sessile or non-polypoid lesions of any size, preoperatively estimated as non-invasive. Seven meta-analysis studies, mainly Eastern, were included in the analysis comparing 124 studies and overall 22954 patients who underwent EMR and ESD procedures. Of these, eighty-two were retrospective, twenty-four perspective, nine case-control, and six cohorts, while three were randomized clinical trials. A total of 18118 EMR and 10379 ESD were completed for a whole of 28497 colorectal sessile or non-polypoid lesions > 5-10 mm in size. In conclusion, it is crucial to enhance the preoperative diagnostic workup, especially in deciding the most suitable endoscopic method for radical resection of flat colorectal lesions at risk of underlying malignancy. Additionally, the ESD necessitates further improvement because of the excessively time-consuming as well as the intraprocedural technical hindrances and related complications. We found a higher rate of en bloc resections and R0 for ESD than EMR for non-pedunculated colorectal lesions. Nevertheless, despite the lower local recurrence rates, ESD had greater perforation rates and needed lengthier procedural times. The prevailing risk for additional surgery in ESD rather than EMR for complications or oncologic reasons is still uncertain.

Early colorectal cancer diagnosed after endoscopic resection: Conservative treatment is safe in most of the cases. Proposal for a risk-based management

INTRODUCTION

Endoscopic resection offers advantages over surgical resection for early colorectal cancer (ECC). However, there might be a presumed risk of recurrence. We aimed to determine the risk of recurrence after endoscopic removal of ECC.

METHODS

A single-centre series of endoscopic resections for ECC. Patients were stratified according to four risk factors: positive resection margins, Haggitt 4, lymphatic/vascular invasion and tumour budding.

RESULTS

We included 127 patients. Haggitt classification was grade 4 in 54.0%. Positive margins were found in 43 (33.9%), 16 (12.6%) had lymphatic or vascular invasion, and 5 (4.0%) had high grade budding. In 82 (64.5%) endoscopic excision was the definitive treatment, 45 (35.4%) underwent surgery. Six patients (13.3%) had residual tumour on specimen and/or node metastases. Postoperative complications occurred in ten (22.2%). At a median follow-up of 63 months, none of the 82 patients treated with endoscopic resection alone had recurrence. After stratifying patients according to risk factors, those who had residual tumour also had ≥2 risk factors.

CONCLUSIONS

Endoscopic follow up might be a valid option for patients with ECC. A risk-adjusted management seems prudent.

A genomic-clinicopathologic Nomogram for the preoperative prediction of lymph node metastasis in gastric cancer

BACKGROUND

Preoperative evaluation of lymph node (LN) state is of pivotal significance for informing therapeutic decisions in gastric cancer (GC) patients. However, there are no non-invasive methods that can be used to preoperatively identify such status. We aimed at developing a genomic biosignature based model to predict the possibility of LN metastasis in GC patients.

METHODS

We used the RNA profile retrieving strategy and performed RNA expression profiling in a large GC cohort (GSE62254, n = 300) from Gene Expression Ominus (GEO). In the exploratory stage, 300 GC patients from GSE62254 were involved and the differentially expressed RNAs (DERs) for LN-status were determined using the R software. GC samples in GSE62254 were randomly allocated into a learning set (n = 210) and a verification set (n = 90). By using the Least absolute shrinkage and selection operator (LASSO) regression approach, a set of 23-RNA signatures were established and the signature based nomogram was subsequently built for distinguishing LN condition. The diagnostic efficiency, as well as the clinical performance of this model were assessed using the decision curve analysis (DCA). Metascape was used for bioinformatic analysis of the DERs.

RESULTS

Based on the genomic signature, we established a nomogram that robustly distinguished LN status in the learning (AUC = 0.916, 95% CI 0.833-0.999) and verification sets (AUC = 0.775, 95% CI 0.647-0.903). DCA demonstrated the clinical value of this nomogram. Functional enrichment analysis of the DERs was performed using bioinformatics methods which revealed that these DERs were involved in several lymphangiogenesis-correlated cascades.

CONCLUSIONS

In this study, we present a genomic signature based nomogram that integrates the 23-RNA biosignature based scores and Lauren classification. This model can be utilized to estimate the probability of LN metastasis with good performance in GC. The functional analysis of the DERs reveals the prospective biogenesis of LN metastasis in GC.

Lactobionic acid-modified chitosan thermosensitive hydrogels that lift lesions and promote repair in endoscopic submucosal dissection

To develop a biomaterial to lift the lesion and promote wound healing in endoscopic submucosal dissection (ESD), we used lactobionic acid (LA) to improve the water solubility of chitosan (CS) and prepared a new three-phase hydrogel system with lactobionic acid-modified chitosan/chitosan/β-glycerophosphate (CSLA/CS/GP). The results indicated that the hydrogel retains temperature-sensitive properties, and CSLA obviously improved the low-temperature fluidity of the hydrogel precursor solution, enabling injection of the hydrogel by endoscopic needle. The mechanical strength and bio-adhesion of the hydrogels were also improved by the addition of CSLA and the hydrogels could be maintained in acidic environment for a few days and exhibit greater protection of cells. The CSLA/CS/GP hydrogels show good cytocompatibility. The heights of cushions elevated by CSLA/CS/GP hydrogels remained ∼ 60 % 2 h post-injection in porcine stomach models. Given the unique characteristics of these materials, the CSLA/CS/GP thermo-sensitive hydrogel is a promising intraoperative biomaterial in ESD.

Differences between two sodium hyaluronate-based submucosal injection materials currently used in Japan based on viscosity analysis

In Japan, two 0.4% sodium hyaluronate (HA)-based submucosal injection materials (SIMs) are currently used in endoscopic submucosal dissection (ESD): MucoUp (HA-Mc) and Ksmart (HA-Ks). HA-Mc and HA-Ks have the same concentration and are, thus, construed by most endoscopists to have no difference. Nevertheless, visual observation conveys the impression that HA-Ks have a higher viscosity than HA-Mc, suggesting that HA-Ks performs better than HA-Mc. This study aimed to examine the differences between HA-Mc and HA-Ks. HA-Ks exhibited higher viscosity due to greater weight-average molecular weight compared with HA-Mc. HA-Ks had significantly greater submucosal elevation height (SEH) than HA-Mc; the SEH of HA-Ks-80% (80% dilution of HA-Ks) was the same as that of HA-Mc. The ESD procedure time was significantly shorter with HA-Ks than with HA-Mc (15.2 ± 4.1 vs. 19.5 ± 5.9; P = 0.049). The total injection volume for HA-Ks was significantly lower than that for HA-Mc (10.8 ± 3.6 vs. 14.4 ± 4.6; P = 0.045). However, no significant difference in these items was observed between HA-Mc and HA-Ks-80%. HA-Mc and HA-Ks were considered to be almost the same. Nonetheless, HA-Ks exhibited higher viscosity and SIM performance than HA-Mc. HA-Ks-80% had almost the same performance as HA-Mc. Thus, understanding SIM performance and characteristics requires a focus on the viscosity of SIMs.

An innovative next-generation endoscopic submucosal injection material with a 2-step injection system (with video)

BACKGROUND AND AIMS

Next-generation submucosal injection materials (SIMs) with higher performance and flexibility than the current SIMs (eg, 0.4% sodium hyaluronate solution [HA]) are expected to improve the outcomes of endoscopic submucosal dissection (ESD) but are difficult to develop. We developed a next-generation SIM by devising a 2-solution-type SIM comprising 2.0% calcium chloride solution (Ca) and 0.4% sodium alginate solution (SA) and evaluated its performance.

METHODS

Viscoelasticity, submucosal elevation height, and injection pressure of HA, SA, and the next-generation SIM were measured. Outcomes of ESDs on pseudo-lesions in ex vivo porcine stomach/colon models were compared.

RESULTS

The dramatic increase in SA viscoelasticity with the addition of Ca facilitated the formation of highly viscous submucosal cushions that can be controlled by endoscopists. The submucosal elevation height of the next-generation SIM was significantly higher than that of HA or SA with the same injection pressure. The ESD procedure time using the next-generation SIM was significantly shorter than that using HA or SA (14.2 ± 6.1 vs 29.2 ± 9.1 minutes, P = .0004, or 14.2 ± 6.1 vs 29.1 ± 5.9 minutes, P <.0001). Furthermore, the total injection volume for the next-generation SIM was considerably lower than that for HA or SA (7.0 ± 0.9 vs 17.2 ± 3.4 mL, P <.0001, or 7.0 ± 0.9 vs 16.2 ± 2.9 mL, P <.0001).

CONCLUSIONS

We developed an ideal next-generation SIM that achieved high performance and high flexibility in ex vivo models. Our findings warrant further investigations in a patient population.

A Focused Review on Advances in Risk Stratification of Malignant Polyps

Colorectal cancer is the third most common cancer in both men and women in the United States, with most cases arising from precursor adenomatous polyps. Colorectal malignant polyps are defined as cancerous polyps that consist of tumor cells invading through the muscularis mucosae into the underlying submucosa (pT1 tumor). It has been reported that approximately 0.5-8.3% of colorectal polyps are malignant polyps, and the potential for lymph node metastasis in these polyps ranges from 8.5% to 16.1%. Due to their clinical significance, recognition of malignant polyps is critical for clinical teams to make treatment decisions and establish appropriate surveillance schedules after local excision of the polyps. There is a rapidly developing interest in malignant polyps within the literature as a result of an increasing number of identifiable adverse histologic features and recent advancements in endoscopic treatment techniques. The purpose of this paper is to have a focused review of the recent histopathologic literature of malignant polyps.

Underwater vs conventional endoscopic mucosal resection in treatment of colorectal polyps: A meta-analysis

BACKGROUND

Underwater endoscopic mucosal resection (UEMR) of colorectal lesions is emerging as an alternative method to conventional endoscopic mucosal resection (EMR); however, it is still controversial whether there is a difference in the effectiveness between UEMR and EMR.

AIM

To evaluate the effectiveness and safety of UEMR in the treatment of colorectal polyps.

METHODS

Clinical studies comparing the effectiveness or safety of UEMR in the treatment of colorectal polyps were searched in medical databases, including PubMed, Embase, Cochrane Library, CNKI, and Wanfang Data, monographs, theses, and papers presented at conferences. Statistical analyses were performed using Revman 5.3 software.

RESULTS

Seven non-randomized controlled trials and one randomized controlled trial met the inclusion criteria. In total, 1382 patients (1511 polyps) were included in the study, including 722 who received UEMR and 789 who received EMR. In the UEMR and EMR groups, the en bloc resection rates were 85.87% and 73.89%, respectively, with a relative risk (RR) value of 1.14 (95% confidence interval [CI]: 1.01-1.30; P < 0.05). In the sub-group analysis, the en bloc resection rate showed no statistically significant difference between the EMR and UEMR groups for polyps less than 20 mm in diameter. However, a statistically significant difference was found between the EMR and UEMR groups for polyps equal to or greater than 20 mm in diameter. The post-endoscopic resection recurrence rates at 3-6 mo of the UEMR and EMR groups were 3.26% and 15.17%, respectively, with an RR value of 0.27 (95%CI: 0.09-0.83; P < 0.05). The post-endoscopic resection recurrence rates of UEMR and EMR at 12 mo were 6.25% and 14.40%, respectively, with an RR value of 0.43 (95%CI: 0.20-0.92; P < 0.05). Additionally, the incidence of adverse events was 8.17% and 6.21%, respectively, with an RR value of 1.07 (95%CI: 0.50-2.30; P > 0.05).

CONCLUSION

UEMR is an effective technique for colorectal polyps and appears to have some advantages over EMR, particularly with regard to some treatment outcomes.

The endoluminal pressures during flexible gastrointestinal endoscopy

In flexible gastrointestinal (GI) endoscopy, endoscopic insufflation is crucial and directly affects visualization. Optimal visualization enables endoscopists to conduct better examinations and administer optimal treatments. However, endoscopic insufflation is typically performed manually and is subjective. We aimed to measure the GI endoluminal pressure during flexible GI endoscopy. Participants underwent esophagogastroduodenoscopy (EGD) at our endoscopy center. Pressure measurement was conducted after completing diagnostic or follow-up EGD. The endoluminal pressure in the esophagus and stomach was measured at 1-s intervals for 1 min while performing EGD for observational and diagnostic purposes. During the measurements, the endoscopists maintained what they subjectively considered to be adequate exposure for screening for lesions by dilating the lumen. Eighty patients were enrolled in this study. The upper GI endoluminal pressure was assessed during EGD without adverse events. The esophageal endoluminal pressure averaged 8.9 (- 3.0 to 20.7) mmHg, and the gastric endoluminal pressure averaged 10.0 (3.0-17.9) mmHg; the upper GI endoluminal pressures were not affected by patient-related factors or the number of endoscopists' postgraduate years. We have successfully obtained the GI endoluminal pressures during EGD. Further accumulation of these data may lead to more stable and reproducible flexible endoscopic diagnosis and intervention.

Features of endoscopic procedure site reaction associated with a recently approved submucosal lifting agent

Endoscopic resection techniques, such as endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD), are frequently aided by injection of submucosal lifting solutions that create a plane for dissection and protect deeper mural layers. ORISE™ gel is a recently approved synthetic lifting solution that produces a localized inflammatory reaction associated with retained gel at the injection site. We describe a series of six cases of ORISE™-associated inflammatory lesions in patients who underwent endoscopic resections. Deposits comprised pale fibrillary or hyalinized eosinophilic material, depending on their age. All cases were associated with an inflammatory reaction composed of foreign-body giant cells and scattered eosinophils. ORISE™ gel extended laterally and deeply beyond residual tumors in all cases. Histochemically, the material proved to be negative for Congo Red, and mucicarmine, faint blue with Alcian blue, but positive for PAS and PAS-D. It stained blue with trichrome. Such deposits were absent in cases, wherein other widely-available lifting solutions were used. We compared ORISE™ deposits to histologically similar extracellular deposits, namely amyloid and pulse granulomata. Unlike ORISE™ material, amyloid deposits appear as waxy, more densely eosinophilic material, and stain positive with Congo Red. Amyloid demonstrated prominent intramucosal and perivascular distributions, features not seen in this series of ORISE™ deposits. Hyalinized pulse granulomata showed strong overlap with ORISE™ deposits, since they also comprise eosinophilic material associated with giant cell reaction. On the other hand, they form ribbons of glassy material in circumscribed lobules, unlike the ill-defined ORISE™ deposits. In summary, we describe the pathologic findings at injection sites in patients who underwent endoscopic procedures aided by the recently approved lifting agent, ORISE™. Pathologists should be aware of its appearance and associated reaction to avoid confusion with other common extracellular deposits seen in the gastrointestinal tract.

Analysis of factors associated with local recurrence after endoscopic resection of gastric epithelial dysplasia: a retrospective study

Background

Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) are widely used techniques for the treatment of gastric epithelial dysplasia. Previous studies have compared the clinical outcome of endoscopic resection for early gastric cancer, but few studies have focused on gastric dysplasia alone. This study aimed to evaluate the long-term prognosis following endoscopic procedures for gastric epithelial dysplasia, investigate differences in local recurrence rates according to the treatment modality, and identify risk factors associated with local recurrence.

Methods

In this retrospective study, local recurrence rates and risk factors associated with local recurrence were compared between 599 patients who underwent EMR and 306 who underwent ESD for gastric epithelial dysplasia from January 2011 to December 2015.

Results

The en bloc resection rate (32.2% vs. 100%, p < 0.001) and complete resection rate (94.8% vs. 99.0%, p = 0.003) were significantly lower in the EMR group than in the ESD group. The local recurrence rate was significantly lower in the ESD group (1.3%) than in the EMR group (4.2%; p = 0.026). There was a significantly increased risk of local recurrence, regardless of lesion location or histologic grade, in patients with lesions > 2 cm (p = 0.002) or red in color (p = 0.03). The ESD group had a significantly lower local recurrence rate, with a higher complete resection rate, than that in the EMR group (p < 0.05). In the case of recurrence after endoscopic resection, most of the recurred lesions were removed through additional endoscopic procedures; there was no difference between the two groups (p = 0.153).

Conclusions

The complete resection rate was significantly higher, and the local recurrence rate was significantly lower, in patients with gastric epithelial dysplasia treated with ESD. Therefore, ESD should be considered the preferred treatment in patients with lesions > 2 cm or showing redness due to an increased risk of local recurrence and EMR may be possible for low-grade dysplasia that is less than 2 cm without surface changes such as redness, depression and nodularity.

Efficacy and Safety of a Novel Submucosal Injection Solution for Resection of Gastrointestinal Lesions

Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) are minimally invasive and efficient techniques for the removal of gastrointestinal (GI) mucosal polyps. In both techniques, submucosal injection solutions are necessary for complete effectiveness and safety during the intervention to be obtained. The main objective of this study was to evaluate the efficacy and safety of a new sterile submucosal injection solution for EMR/ESD used within a clinical protocol in patients with intestinal polyps. We carried out a prospective study between 2016 and 2017 with patients who attended the Endoscopy Consultation—Digestive Department of Primary Hospital. Patients were selected for EMR/ESD after the application of clinical protocols. Thirty-six patients were selected (≥ 66 years with comorbidities and risk factors). Lesions were located mainly in the colon. Our solution presented an intestinal lift ≥ 60 min in EMR/ESD and a high expansion of tissue, optimum viscosity, and subsequent complete resorption. The genes S100A9 and TP53 presented an expression increase in the distal regions. TP53 and PCNA were the only genes whose expression was increased in polyp specimens vs. the surrounding tissue at the mRNA level. In EMR/ESD, our solution presented a prolonged effect at the intestinal level during all times of the intervention. Thus, our solution seems be an effective and safe alternative in cases of flat lesions in both techniques.

Endoscopic submucosal dissection is associated with less pathologic uncertainty than endoscopic mucosal resection in diagnosing and staging Barrett's-related neoplasia

BACKGROUND & AIMS

Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) have demonstrated similar efficacy in removal of neoplastic esophageal lesions. However, significant controversy exists over the preferred resection technique. Our primary aim was to compare the pathologic specimens produced via EMR and ESD and secondarily gauge their effect on clinical decision making and patient outcomes.

METHODS

Using a retrospective cohort study design, all esophageal Barrett's-associated neoplastic lesions resected by a single provider from 2012 to 2017 were reviewed. The pathology was re-reviewed by two blinded authors for diagnosis, margins, and adverse outcomes and recurrence rates were also collected.

RESULTS

Thirty-one EMR and 20 ESD cases were identified. Baseline demographics and lesion characteristics were similar. ESD produced more R0 resections and more en bloc resections compared to EMR. EMR produced more equivocal lateral (13/31, 41.9% vs 1/20, 5.0%) and vertical margins (13/31, 41.9% vs. 0/20, 0%, both P < 0.05). This led to an inability to reach a definitive diagnosis in 13/31 EMR vs 0/20 ESD pathology specimens (P = 0.003). Of the 13 EMR specimens with equivocal pathology, 11 were noted to have 'at least intramucosal adenocarcinoma'. Four of the 11 patients chose to undergo elective esophagectomy with final surgical pathology demonstrating ≤T1a disease in 2, and ≥T1b disease in two.

CONCLUSION

Compared to ESD, EMR was associated with greater pathologic uncertainty in Barrett's-associated neoplasia.

Multibending scope use for reduction of perforation risks in endoscopic submucosal dissection

AIMS

To identify areas that are difficult to access by the single scope at the time of endoscopic submucosal dissection (ESD) and examine the effectiveness, en-bloc, R0 resection, and perforation rate after changing to multibending scope at the same site.

MATERIAL AND METHODS

When the direct visualization of the submucosal layer became impossible with Q260J or in the position where the device became vertical and peeling became impossible in parallel, we decided to change to the multibending 2TQ260M scope to record the position where the change was effective and the perforation rate.

RESULTS

A total of 315 lesions were studied. Of the 12 sites, ESD was completed using the Q260J alone at four sites. The 2TQ260M scope was used with greater frequency at the fornix (88.9%) and on the line of the lesser curvature of the stomach (37.1%). In the cases with observed perforations (0.9%), the submucosal layer was not elevated due to the adhesion caused by strong fibrosis. None of the cases involving the change to 2TQ260M was ineffective, nor were perforations observed, and all resected specimens were en-bloc and R0 resections.

CONCLUSIONS

The success rate of this scope may help clinicians perform ESD with greater understanding.

Colorectal endoscopic submucosal dissection is here to stay

Endoscopic mucosal resection (EMR) or mucosectomy and endoscopic submucosal dissection (ESD) are both techniques that have modified the therapeutic outlook of superficial gastrointestinal tract lesions and neoplasms. EMR is used for the en-bloc excision of lesions smaller than 2-3 cm or the piecemeal resection of larger ones. In theory, ESD achieves higher rates of en-bloc resections as compared to EMR with a lower rate of recurrence; however, it shows a higher percentage of complications, particularly in inexperienced centers or in centers at the start of their learning curve.

Histopathological Findings Related to ORISE™ Injectable Submucosa Lifting Agent Used in the Endoscopic Mucosal Resection of Bowel Neoplasms: A Review of Three Cases

The use of nonsaline injectable lifting agents is now routine in the performance of endoscopic mucosal resection of bowel neoplasms (EMR). These agents are used to elevate the mucosa from the muscularis propria and permit more a complete resection of the lesion while mitigating risk of possible thermal injury to the bowel wall and thus preventing perforation. After injection, these new agents, which are replacing normal saline, often remain present in the tissues for some time following the procedure and may be identified in the resection specimens where they may mimic a number of other conditions such as mucin pools, lymphangiomas, granulomatous inflammation, and amyloid deposition. We describe the histological findings associated with the use of nonsaline injectable mucosal lifting agents. Awareness of these agents and their associated artefact may reduce misdiagnosis or the use of unnecessary ancillary studies and highlights the importance of proving relevant clinical information on submission of specimens for pathological examination.

ASGE review of adverse events in colonoscopy

Colonoscopy is the most commonly performed endoscopic procedure and overall is considered a low-risk procedure. However, adverse events (AEs) related to this routinely performed procedure for screening, diagnostic, or therapeutic purposes are an important clinical consideration. The purpose of this document from the American Society for Gastrointestinal Endoscopy's Standards of Practice Committee is to provide an update on estimates of AEs related to colonoscopy in an evidence-based fashion. A systematic review and meta-analysis of population-based studies was conducted for the 3 most common and important serious AEs (bleeding, perforation, and mortality). In addition, this document includes an updated systematic review and meta-analysis of serious AEs (bleeding and perforation) related to EMR and endoscopic submucosal dissection for large colon polyps. Finally, a narrative review of other colonoscopy-related serious AEs and those related to specific colonic interventions is included.

Comparisons of therapeutic outcomes in patients with nonampullary duodenal neuroendocrine tumors (NADNETs): A multicenter retrospective study

Duodenal neuroendocrine tumors (DNETs) are rare tumors that are occasionally found during upper endoscopies. The incidence of DNETs is increasing, although the data regarding treatment outcomes are insufficient. The aim of this study was to evaluate the treatment outcomes in patients with nonampullary DNETs who underwent endoscopic resection or surgery. We evaluated the medical records of patients who were diagnosed with nonampullary DNETs from 2004 to 2017 in 7 university hospitals. We retrospectively analyzed clinical characteristics and compared therapeutic outcomes based on the endoscopic lesion size and treatment method. We ultimately enrolled 60 patients with nonampullary DNETs who underwent endoscopic and surgical treatments. In the endoscopic treatment group, the en bloc resection, endoscopic complete resection (CR) and pathologic CR rates were 88%, 92%, and 50%, respectively. The endoscopic treatment group was divided into 3 subgroups based on the lesion size (1-5 mm, 6-10 mm, and ≥11 mm). The pathologic CR rate was significantly lower in the subgroup with a lesion size ≥11 mm (0%, P = .003) than those in the other 2 subgroups. Lymphovascular invasion occurred significantly more frequently (33.3%, P = .043) among those with a lesion size ≥11 mm. The pathologic CR rate in the surgical treatment group was higher (90.9%) than that in the endoscopic treatment group (50%, P = .017). Surgical treatment appears to be a more appropriate choice because of the risks of incomplete resection and lymphovascular invasion after endoscopic treatment for lesions larger than 11 mm.

Clinical outcomes of positive resection margin after endoscopic mucosal resection of early colon cancers

BACKGROUND/AIMS

When determining the subsequent management after endoscopic resection of the early colon cancer (ECC), various factors including the margin status should be considered. This study assessed the subsequent management and outcomes of ECCs according to margin status.

METHODS

We examined the data of 223 ECCs treated by endoscopic mucosal resection (EMR) from 215 patients during 2004 to 2014, and all patients were followed-up at least for 2 years.

RESULTS

According to histological analyses, the margin statuses of all lesions after EMR were as follows: 138 cases (61.9%) were negative, 65 cases (29.1%) were positive for dysplastic cells on the resection margins, and 20 cases (8.9%) were uncertain. The decision regarding subsequent management was affected not only by pathologic outcomes but also by the endoscopist's opinion on whether complete resection was obtained. Surgery was preferred if the lesion extended to the submucosa (odds ratio [OR], 25.46; 95% confidence interval [CI], 7.09-91.42), the endoscopic resection was presumed incomplete (OR, 15.55; 95% CI, 4.28-56.56), or the lymph system was invaded (OR, 13.69; 95% CI, 1.76-106.57). Fourteen patients (6.2%) had residual or recurrent malignancies at the site of the previous ECC resection and were significantly associated with presumed incomplete endoscopic resection (OR, 4.59; 95% CI, 1.21-17.39) and submucosal invasion (OR, 5.14; 95% CI, 1.18-22.34).

CONCLUSIONS

Subsequent surgery was associated with submucosa invasion, lymphatic invasion, and cancer-positive margins. Presumed completeness of the resection may be helpful for guiding the subsequent management of patients who undergo endoscopic resection of ECC.

Clips for managing perforation and bleeding after colorectal endoscopic mucosal resection

INTRODUCTION

The most commonly used treatment for advanced colorectal adenomas is endoscopic mucosal resection (EMR). The increased number of EMRs since the introduction of the screening program for colorectal cancer has resulted in an increase in EMR-related complications. This review summarizes the current knowledge for the use of clips for the treatment and prevention of complications after EMR.

AREAS COVERED

The historical development of clips is summarized and their properties are evaluated. An overview is presented of the evidence for therapeutic and prophylactic clipping for bleeding or perforation after EMR in the colon. Several clipping techniques are discussed in relation to the efficacy of wound closure. Furthermore, new techniques that will likely influence the use of clips in the future endoscopic practice, such as endoscopic full-thickness resection (eFTR) are also highlighted.

EXPERT COMMENTARY

Most research focuses on prophylactic clipping for delayed bleeding after EMR of large adenomas. We advocate a distance of 0.5-1.0 cm between aligning clips. This focus may likely shift from bleeding to perforation. Here, endoscopic treatment with through-the-scope clips and large-diameter clips may well replace surgery. The future role of clips will also depend on the further development of new endoscopic technologies, such as eFTR.

Update on the Diagnosis and Management of Gastric Intestinal Metaplasia in the USA

Gastric intestinal metaplasia (GIM) is a premalignant condition that can lead to intestinal-type gastric adenocarcinoma. It is characterized by a change in the gastric mucosa to a small-intestinal phenotype. Infection with Helicobacter pylori is the most common factor associated with GIM. Although GIM is typically a histologic diagnosis, various techniques have been developed to enable the endoscopic identification of GIM. There are presently no widely accepted guidelines on screening and surveillance strategies in patients with GIM in the USA. The aim of this review is to provide an update regarding the problem, diagnosis, and management of GIM in the USA.

Comparison of two methods for endoscopic full-thickness resection of gastrointestinal lesions using OTSC

Background and aims: The aim of this study was to compare and analyze the feasibility and safety of two methods of endoscopic full-thickness resection (EFTR) for the management of challenging epithelial and subepithelial neoplasms that are not amenable to resection techniques.Material and methods: This was a retrospective case series study of patients who underwent one of two methods of EFTR, resection using ESD knives and post-resection closure with OTSC (Group 1), or closure with OTSC and secondary EFTR with snare (Group 2).Results: Of 11 patients, six were in Group 1 and five in Group 2. The mean time of the EFTR procedure was 76.83 ± 34.97 min in Group 1 which is significantly longer than that of Group 2 (p = .0128). The mean time of OSTC closure and length of hospital stay of Group 1 were also longer compared to Group 2, but the difference was not significant. Complete resection (R0) and technical success rates of Group 1 and Group 2 were 83.3% and 100% (p = .338), respectively. VAS scores of Group 1 immediately after the operation and after 24 h are significantly higher than those of Group 2 (p = .047 and p = .009, respectively). In Group 1, one patient had delayed perforation which led to fever and pneumoperitoneum, and one patient developed abdominal pain. No complications associated with the endoscopic procedure were observed in Group 2.Conclusion: EFTR of pre-resection closure are potentially faster compared with the concept of applying closure after EFTR. Larger prospective controlled studies comparing these two techniques are warranted in the future.

Mucosal loss as a critical factor in esophageal stricture formation after mucosal resection: a pilot experiment in a porcine model

BACKGROUND AND AIM

Esophageal stricture is a major complication of large areas endoscopic submucosal dissection (ESD). Until now, the critical mechanism of esophageal stricture remains unclear. We examined the role of mucosal loss versus submucosal damage in esophageal stricture formation after mucosal resection using a porcine model.

MATERIALS AND METHODS

Twelve swine were randomly divided into two groups, each of 6. In each group, two 5-cm-long submucosal tunnels were made to involve 1/3rd of the widths of the anterior and posterior esophageal circumference. The entire mucosal roofs of both tunnels were resected in group A. In group B, the tunnel roof mucosa was incised longitudinally along the length of the tunnel, but without excision of any mucosa. Stricture formation was evaluated by endoscopy after 1, 2, and 4 weeks, respectively. Anatomical and histological examinations were performed after euthanasia.

RESULTS

Healing observed on endoscopy in both groups after 1 week. Group A (mucosa resected) developed mild-to-severe esophageal stricture, dysphagia, and weight loss. In contrast, no esophageal stricture was evident in group B (mucosa incisions without resection) after 2 and 4 weeks, respectively. Macroscopic examination showed severe esophageal stricture and shortening of esophagus in only group A. Inflammation and fibrous hyperplasia of the submucosal layer was observed on histological examination in both groups.

CONCLUSION

The extent of loss of esophageal mucosa appears to be a critical factor for esophageal stricture. Inflammation followed by fibrosis may contribute to alteration in compliance of the esophagus but is not the main mechanism of postresection stricture.

Solutions for submucosal injection: What to choose and how to do it

During the past decades, endoscopic resection techniques have gradually improved and gained more importance for the management of premalignant lesions and early cancers. These endoscopic resection techniques can be divided in 3 major groups: snare polipectomy, endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD). The use of submucosal injection is essential for the majority of EMR techniques and is an integral part of ESD, whereas during polipectomy it is not crucial in most cases except to prevent bleeding in large polyps and/or those with large stalks as an alternative to mechanical methods. Injection provides a lifting up effect of the lesion separating it from the muscular layer, thereby reducing thermal injury and the risk of perforation and bleeding while also facilitating en-bloc resection by improving technical feasibility. With this work, we aim to review the most common endoscopic resection techniques and the importance of submucosal injection in each one of them. For that, we present some of the most commonly used submucosal injection solutions, taking into account their advantages and disadvantages. We also discuss, based on current recommendations and our own experience, how and when to preform submucosal injection, depending on lesions features and endoscopic resection technique that´s being used, to assure complete resection and to prevent associated adverse events. Finally, we also present and discuss some new proposed submucosal injection solutions, endoscopic resection techniques and devices that may have a major impact on the future of therapeutic endoscopy.

A task and performance analysis of endoscopic submucosal dissection (ESD) surgery

BACKGROUND

ESD is an endoscopic technique for en bloc resection of gastrointestinal lesions. ESD is a widely-used in Japan and throughout Asia, but not as prevalent in Europe or the US. The procedure is technically challenging and has higher adverse events (bleeding, perforation) compared to endoscopic mucosal resection. Inadequate training platforms and lack of established training curricula have restricted its wide acceptance in the US. Thus, we aim to develop a Virtual Endoluminal Surgery Simulator (VESS) for objective ESD training and assessment. In this work, we performed task and performance analysis of ESD surgeries.

METHODS

We performed a detailed colorectal ESD task analysis and identified the critical ESD steps for lesion identification, marking, injection, circumferential cutting, dissection, intraprocedural complication management, and post-procedure examination. We constructed a hierarchical task tree that elaborates the order of tasks in these steps. Furthermore, we developed quantitative ESD performance metrics. We measured task times and scores of 16 ESD surgeries performed by four different endoscopic surgeons.

RESULTS

The average time of the marking, injection, and circumferential cutting phases are 203.4 (σ: 205.46), 83.5 (σ: 49.92), 908.4 s. (σ: 584.53), respectively. Cutting the submucosal layer takes most of the time of overall ESD procedure time with an average of 1394.7 s (σ: 908.43). We also performed correlation analysis (Pearson's test) among the performance scores of the tasks. There is a moderate positive correlation (R = 0.528, p = 0.0355) between marking scores and total scores, a strong positive correlation (R = 0.7879, p = 0.0003) between circumferential cutting and submucosal dissection and total scores. Similarly, we noted a strong positive correlation (R = 0.7095, p = 0.0021) between circumferential cutting and submucosal dissection and marking scores.

CONCLUSIONS

We elaborated ESD tasks and developed quantitative performance metrics used in analysis of actual surgery performance. These ESD metrics will be used in future validation studies of our VESS simulator.