Endoscopic Submucosal Dissection Operation Research Articles

Effect of Time-Limited Training on Endoscopic Submucosal Dissection in an Ex Vivo Porcine Stomach Model: A Prospective Randomized Controlled Study

Abstract Introduction Endoscopic submucosal dissection (ESD) is the first choice for superficial tumor resection. There is no report on whether the training effect is affected by limiting the operation time of each ESD operation. This study aimed to prospectively evaluate the efficiency of time-limited ESD training by using an ex vivo porcine stomach model. Methods ESD was performed in accordance with the standard procedure on ex vivo porcine stomach model. The time-limited group required each operation time to be controlled within 30 minutes, and the nonlimited group did not limit the operation time. The en bloc resection rate, surface area of the resected specimen, procedure speed, and perforation rate were compared in the two groups. Results Compared with the en bloc resection rate in the time-limited group, that in the nonlimited group was significantly higher in ESD-1 and ESD-2. In each ESD procedure, the median resection area in the nonlimited group was significantly larger than that in the time-limited group. The difference in median procedure speed between the two groups in ESD-1 to ESD-4 did not reach significance in the statistical analysis. The speed of ESD-5 in the time-limited group was significantly higher than that of the nonlimited group. The perforation rate of the time-limited group was similar to that of the nonlimited group. Conclusion Limiting the training time does not help the trainees to complete large resection of lesions and reduce the perforation rate, but it may help to improve the operation speed.

Endoscopic Screening for Missed Lesions of Synchronous Multiple Early Gastric Cancer during Endoscopic Submucosal Dissection.

To evaluate the value of endoscopic screening during endoscopic submucosal dissection (ESD) in the detection of synchronous multiple early gastric cancer (SMEGC) and the risk factors for missed diagnosis of SMEGC. We conducted gastric endoscopic screening during ESD operation in 271 patients with early gastric cancer (EGC) referred for ESD, and endoscopic follow-up within 1 year after the operation. The detection and characteristics of SMEGC were analyzed in three stages: before ESD, during ESD operation, and within 1 year after ESD. SMEGC was detected in 37 of 271 patients (13.6%). Among them, 21 patients with SMEGC (56.8%) were diagnosed before ESD, 9 (24.3%) were diagnosed with SMEGC by endoscopic screening during ESD operation, and 7 (18.9%) were found to have EGC lesions in the stomach during postoperative endoscopic follow-up within 1 year. The preoperative missed detection rate of SMEGC was 43.2%, and the rate of missed detection could be reduced by 24.3% (9/37) with endoscopic screening during ESD operation. Missed SMEGC lesions were more common in flat or depressed type and smaller in size than the lesions found before ESD. The presence of severe atrophic gastritis and age ≥60 years were significantly correlated with SMEGC (P < 0.05), while multivariate analysis showed that age ≥60 years was an independent risk factor (OR = 2.63, P < 0.05) for SMEGC. SMEGC lesions are apt to be missed endoscopically. Special attention should be paid to small, depressed, or flat lesions in detecting SMEGC, especially in elderly patients or (and) patients with severe atrophic gastritis. Endoscopic screening during ESD operation can effectively reduce the missed diagnosis rate of SMEGC.

A variable stiffness manipulator with multifunctional channels for endoscopic submucosal dissection.

Endoscopic submucosal dissection (ESD) has become the main treatment for early esophageal and gastric cancers, but the insufficient stiffness and large diameter of current devices increase the difficulty in operation. To address the above problems, this study proposes a variable stiffness manipulator with multifunctional channels for ESD. The proposed manipulator has a diameter of just 10mm and highly integrates a CCD camera, two optical fibers, two channels for instruments, and one channel for water and gas. Additionally, a compact wire-driven variable stiffness mechanism is also integrated. The drive system of the manipulator is designed, and the kinematics and workspace are analyzed. The variable stiffness and practical application performance of the robotic system are tested. The motion tests verify that the manipulator has sufficient workspace and motion accuracy. The variable stiffness tests show that the manipulator achieves 3.55 times of stiffness variation instantly. Further insertion tests and operation test demonstrates that the robotic system is safe and can satisfy the needs in motion, stiffness, channels, image, illumination, and injection. The manipulator proposed in this study highly integrates six functional channels and a variable stiffness mechanism in a 10mm diameter. After kinematic analysis and testing, the performance and application prospect of the manipulator are verified. The proposed manipulator can promote the stability and accuracy of ESD operation.

Endoscopic submucosal dissection training: evaluation of an ex vivo training model with continuous perfusion (ETM-CP) for hands-on teaching and training in China

BackgroundThe existing ex vivo models of endoscopic submucosal dissection (ESD) cannot simulate intraoperative hemorrhage well. We aimed to establish an ESD training method by applying an ex vivo training model with continuous perfusion (ETM-CP).MethodsFour training sessions were conducted for 25 novices under the guidance of 2 experts. Eventually, 10 novices completed ESD operations on a total of 89 patients after the training. The resection effectiveness, resection speed, complication rate, and novice performance before and after the training were compared. The data regarding the effects of the training and the model were gathered through a questionnaire survey.ResultsIn terms of the simulation effect of the model, ETM-CP was evaluated as similar to the live pig in all aspects (P > 0.05). The questionnaire analysis revealed that the ESD theoretical knowledge, skill operation, and self-confidence of novices were improved after the training (P < 0.05). The resection time per unit area had a correlation with the number of training periods (rs = – 0.232). For novice performance, the resection time per unit area was shortened (P < 0.05). There was no difference in patient performance between the novice group and the expert group after the training in terms of en bloc resection, R0 resection, complication rate, endoscopic resection bleeding (ERB) score, muscularis propria injury (MPI) score, and resection time per unit area (P > 0.05).ConclusionThe ETM-CP is effective for ESD training.

Associate factors for endoscopic submucosal dissection operation time and postoperative delayed hemorrhage of early gastric cancer.

Endoscopic submucosal dissection (ESD) is a treatment for early gastric cancer with the advantages of small invasion, fewer complications, and a low local recurrence rate. However, there is a high risk of complications such as bleeding and perforation, and the operation time is also longer. ESD operation time is closely related to bleeding and perforation. To investigate the influencing factors associated with ESD operation time and postoperative delayed hemorrhage to provide a reference for early planning, early identification, and prevention of complications. We conducted a retrospective study based on the clinical data of 520 patients with early gastric cancer in the Second Affiliated Hospital of Hainan Medical University from January 2019 to December 2021. The baseline data, clinical features, and endoscopic and pathological characteristics of patients were collected. The multivariate linear regression model was used to investigate the influencing factors of ESD operation time. Logistic regression analysis was carried out to evaluate the influencing factors of postoperative delayed hemorrhage. The multivariate analysis of ESD operation time showed that the maximum lesion diameter could affect 8.815% of ESD operation time when other influencing factors remained unchanged. The operation time increased by 3.766% or 10.247% if the lesion was mixed or concave. The operation time increased by 4.417% if combined with an ulcer or scar. The operation time increased by 3.692% if combined with perforation. If infiltrated into the submucosa, it increased by 2.536%. Multivariate analysis of delayed hemorrhage after ESD showed that the maximum diameter of the lesion, lesion morphology, and ESD operation time were independent influencing factors for delayed hemorrhage after ESD. Patients with lesion ≥ 3.0 cm (OR = 3.785, 95%CI: 1.165-4.277), lesion morphology-concave (OR = 10.985, 95%CI: 2.133-35.381), and ESD operation time ≥ 60 min (OR = 2.958, 95%CI: 1.117-3.526) were prone to delayed hemorrhage after ESD. If the maximum diameter of the lesion in patients with early gastric cancer is ≥ 3.0 cm, and the shape of the lesion is concave, or accompanied by an ulcer or scar, combined with perforation, and infiltrates into the submucosa, the ESD operation will take a longer time. When the maximum diameter of the lesion is ≥ 3.0 cm, the shape of the lesion is concave in patients and the operation time of ESD takes longer time, the risk of delayed hemorrhage after ESD is higher.

Design and validation of performance-oriented injectable chitosan thermosensitive hydrogels for endoscopic submucosal dissection

Endoscopic submucosal dissection (ESD) is a challenging procedure. The use of biomaterials to improve the operator's convenience (operating affinity) has received little attention. We prepared two thermosensitive hydrogels, lactobionic acid-modified chitosan/chitosan/β-glycerophosphate thermosensitive hydrogel (hydrogel 1) and its lyophilized powders (hydrogel 2), characterized their physicochemical properties and evaluated their performance in ESD experiments on large animals, by comparing with the commonly used normal saline (NS) and glycerin fructose (GF). These hydrogels showed good low-temperature fluidity; their viscosities at 4 °C were 92.2 mPa.s and 26.9 mPa.s, respectively. The hydrogels provided significantly better viscoelastic properties than NS and GF. The relaxation moduli of hydrogels were higher than those of NS and GF when the strains were 1 %, 5 %, and 10 %. The hydrogels can be maintained for seven days, even at pH 1, after which they degrade entirely. In pig model experiments, we performed submucosal injection and ESD procedures in the stomach and esophagus. The cushion height produced by the hydrogels was higher than those of NS and GF 30 min after injection. The ESD operation time for hydrogels was significantly shorter. Postoperative wound observation and histological analysis showed that the hydrogels promoted wound healing. The two hydrogels differed in fluidity, viscoelasticity, and other properties, which makes it possible to select the hydrogels according to the size and location of the lesion during ESD operation, and hydrogel 2 may be more suitable for use in lengthier procedures. In general, the hydrogels showed good performance, facilitated the intraoperative operation of ESD, shorten the operation time and promoted wound healing, which is of great significance for reducing the complications and reducing the threshold of ESD operation and further promoting the popularity of ESD.

Comparing Different Anesthesia Methods on Anesthetic Effect and Postoperative Pain in Patients with Early Gastric Cancer during Endoscopic Submucosal Dissection

Endoscopic submucosal dissection (ESD) is a minimally invasive technique to completely peel the pathological mucosa from the submucosa under endoscopy, which has been often utilized to treat early gastric cancer. During the operation, anesthesia is required to reduce the discomfort due to the complexity, high risk, and longtime operation of ESD. In this study, we compared different anesthesia methods on anesthetic effect and postoperative pain in patients (≥65 years old) with early gastric cancer during ESD. For this purpose, 60 patients with early gastric cancer who were more than 65 years old were selected from January 2019 to December 2021, where 30 patients treated with simple intravenous general anesthesia were divided into the simple group and 30 patients treated with intravenous combined inhalation general anesthesia were regarded as the composite group. The hemodynamic index, wake-up time, postoperative pain intensity, operation time, and the incidence of adverse reactions were compared between the two groups. For the hemodynamic index before incision, after incision, and at the end of the operation, the mean arterial pressure (MAP) in the composite group was higher than that in the simple group (P < 0.05) and the heart rate (HR) was lower than that in the simple group (P < 0.05). After the ESD operation, the wake-up time and visual analogue scale (VAS) in the composite group were lower than those in the simple group (P < 0.05). In addition, the ESD operation time and incidence of adverse reactions in the composite group was significantly lower than that in the simple group (P < 0.05). These results showed that intravenous combined inhalation general anesthesia had a good anesthetic effect, stable hemodynamics during ESD operation, and slight postoperative pain.

Analysis of Prognostic Risk Factors of Endoscopic Submucosal Dissection (ESD) and Curative Resection of Gastrointestinal Neuroendocrine Neoplasms.

Objective To explore the prognostic risk factors of ESD curative resection of gastrointestinal-neuroendocrine neoplasms (GI-NENs). Methods A total of 97 patients treated with ESD successfully in our hospital were selected, their surgical site, size, number of resection lesions, operation time, intraoperative complications (such as bleeding and perforation), and treatment status were recorded, and the number of hemostatic clamps used after the postoperative follow-up results and the independent risk factors for ESD complications were obtained through the comparison between the noncomplication group and the ESD complication group using regression analysis. Results A total of 97 patients with gastrointestinal neuroendocrine tumors were treated with ESD. 61 were males, 36 were females, the ratio of male to female was 1.7 : 1, onset age was 20–78 years old, and median onset age was 50 years old. In 81 cases, tumors were located in the stomach, 10 in the duodenum, and 6 in the rectum. A total of 103 lesions were detected by endoscopy, including 1 case with 2 sites in the stomach, 5 cases with 2 sites in the rectum, and the rest were single. The tumor diameter was 0.3 ∼ 2.5 cm, and the median diameter was 0.6 cm; there were 25 sites with a diameter less than 5 cm. There were 57 places with 10 mm, 16 places with 10–15 mm, and 5 places with >15 mm. All ESD operations were performed in one piece, with a total resection rate of 100%; 89.6% (60/67) of postoperative pathology showed negative basal, and 90.3% (56/62) showed negative resection margin, with a complete resection rate of 88.9% (48/54). ESD's operation time is 6 ∼ 66 min, and the median time is 18 min. During the operation, 5 cases had small amount of bleeding, 3 cases were perforated, 2 cases of delayed postoperative bleeding, 1 case of bleeding was caused by the patient's failure to follow the advice of the doctor to eat a large amount of solid food too early, and 1 case of delayed perforation (all recovered and discharged). ESD operation that bled, age, gender, and perforation location, pathological grade, pathological classification, tumor diameter, tumor surface, operation time, number of titanium clips, origin, echo uniformity, and echo level were statistically insignificant (P > 0.05). Postoperative bleeding was related to the operation time (P=0.017), but it was not an independent risk factor for postoperative bleeding (P=0.118; OR, 0.226; 95% CI, 0.035–1.461). 59 cases were followed up by endoscopy after the operation, and recurrence or no new tumors were found. Conclusion ESD is an effective and safe treatment method for gastrointestinal neuroendocrine tumors with a diameter of 1-2 cm without invading the muscularis propria. The intraoperative complications seem to have little relationship with the patient; postoperative delayed bleeding is closely related to the ESD operation time but it is not an independent risk factor.

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

Background Colorectal endoscopic submucosal dissection (ESD) is a complex operation. Effective traction is crucial. We have successfully used an orthodontic rubber band (ORB) combined with the clip traction method to assist ESD (ORB-ESD). The aim of this retrospective study is to describe the method and to compare the efficacy and safety of ORB-ESD versus conventional ESD in the treatment of superficial colorectal tumors. Methods We retrospectively analyzed the data of patients with superficial colorectal tumor (with diameter ≥ 20 mm) who received either ORB-ESD (n = 34) or conventional ESD (n = 90) between January 2019 and September 2020. Propensity score matching (PSM) was used to match the clinical data of 31 pairs of patients in each group. Results Operation time was significantly shorter for ORB-ESD than for conventional ESD (34.5 minutes vs. 56 minutes, P ≤ 0.001). In the propensity-matched cohorts, the operation time remained significantly shorter in the ORB-ESD patients (35 minutes vs. 50 minutes, P = 0.001). Postoperative adverse events, en bloc resection rate, and R0 resection rate were comparable between the two groups (P > 0.05), both before and after propensity score matching. In the ORB subgroup analysis, the trainee and expert ESD operation times were similar (37 (26–53) vs. 33.5 (26–37) minutes, respectively; P = 0.274). Conclusion ORB-ESD appears to be an effective technique for ESD of colorectal cancer. Our findings need to be confirmed in large prospective multicenter studies.

Analysis of risk factors for delayed bleeding after endoscopic submucosal dissection of gastric epithelial neoplasm

Objective: To determine the potential risk factors of delayed hemorrhage after endoscopic submucosal dissection (ESD) in patients with early gastric carcinomas or precancerous lesions. Methods: The clinical data of 637 patients with early gastric carcinomas (EGC) who treated with ESD in Department of Endoscopy at Cancer Hospital, Chinese Academy of Medical Sciences, from August 2013 to August 2019, were retrospectively analyzed. Univariate analysis and multivariate logistic analysis were conducted to evaluate the risk factors associated with delayed bleeding. Results: A total of 699 lesions in 637 patients, of which 696 lesions were resected enbloc, the curative resection rate was 92.1% (644/699). The pathological diagnosis after ESD showed that 46 cases were low-grade intraepithelial neoplasia, 71 were high-grade intraepithelial neoplasia, and 582 were cancer. Delayed bleeding occurred in 74 lesions, while other 625 lesions without postoperative bleeding. The incidence was 10.6%. Compared with the non-bleeding group, there were statistically significant differences in the maximum length of the lesion, the gross shape of the lesion, the control of intra operative bleeding, and the operation time in the delayed bleeding group (P<0.05). Multivariate logistic regression analysis showed that the maximum length of the lesion and the gross shape of the lesion were independent factors of delayed bleeding after ESD. Delayed bleeding was inclined to occur in patients with lesion size ≥3.0 cm (OR=1.958, 95% CI: 1.162-3.299) and the superficial and flat lesion (OR=10.598, 95% CI: 1.313-85.532) after ESD. Conclusions: The maximum length of the lesion and the gross shape of the lesion are independent impact factors of delayed bleeding occurring in patients with EGC and precancerous lesions after ESD. Patients with lesion size≥3 cm, or superficial flat lesion should be paid attention after ESD operation. It needs to take timely measures to prevent the very likely bleeding in order to ensure postoperative recovery and improve the quality of life for postoperative patients.

Carcinoembryonic Antigen Related Cell Adhesion Molecule 6 Promotes Carcinogenesis of Gastric Cancer and Anti-CEACAM6 Fluorescent Probe Can Diagnose the Precancerous Lesions.

The diagnosis of precancerous lesions or early gastric cancer (EGC) is very important for patient survival. Molecular imaging is a visualized method that can easily and precisely diagnose tumors. However, there are currently few studies about molecular imaging diagnosis of EGC. Here, we studied the expression of carcinoembryonic antigen related cell adhesion molecule 6 (CEACAM6) in the progression of GC. Then, the regulatory roles of CEACAM6 in GC cells were investigated. Furthermore, both the fluorescent-labeled and near infrared molecular-labeled probes were synthesized, and the diagnostic value of anti-CEACAM6 probes in GC was evaluated in vivo using a GC mice model as well as in vitro using fresh dysplastic gastric mucosa obtained from endoscopic submucosal dissection (ESD) operations. Our study showed that CEACAM6 was over expressed in GC tissues compared to adjacent tissues, and the patients with higher CEACAM6 expression had lower survival time. Moreover, the CEACAM6 expression was higher in the dysplastic gastric mucosa than in the adjacent normal mucosa. CEACAM6 accelerated the growth, proliferation, and invasion of GC cells in the in vitro and in vivo studies. Moreover, up regulated CEACAM6 can induce the expression of proteins related to GC progression. Furthermore, the anti-CEACAM6 probes exhibited good affinity with GC cell lines. The probes can track tumors as well as metastases in the mice model in vivo, and can precisely identify the area of dysplastic gastric mucosa using specimens obtained from ESD operations by wide field fluorescent endoscopy. The surface micro features of the mucosa can also be observed using fluorescent micro endoscopy, and the degree of atypia can be distinguished by both the signal intensity and surface micro morphology. CEACAM6 is a key molecular marker in GC progression, and the anti-CEACAM6 probe-assisted fluorescent endoscopy may be a potential option for the diagnosis of precancerous lesions.

Controlled hypertension under hemostasis prevents post-gastric endoscopic submucosal dissection bleeding: a prospective randomized controlled trial.

Endoscopic submucosal dissection (ESD) is a prominent minimally invasive operative technique for treating early gastrointestinal tumors but can result in postoperative bleeding. We conducted a randomized controlled trial to determine whether increasing blood pressure under hemostasis during gastric ESD to identify potential bleeding spots reduces the risk of post-ESD bleeding. In this randomized, controlled, single-blinded clinical trial, 309 patients with early gastric cancer who were admitted to a hospital to undergo ESD were recruited from March 2017 to February 2018 and were randomized into intervention and control groups. In the control group, patients underwent normal ESD. In the intervention group, we increased patients' blood pressure to 150mmHg for 5min using a norepinephrine pump (0.05μg/kg/min initial dose) after the specimen was extracted during the ESD operation to identify and coagulate potential bleeding spots with hot biopsy forceps. Our primary outcome was the incidence of postoperative bleeding over 60-day follow-up. The incidence of post-ESD bleeding was lower in the intervention group (1.3%, 2/151) than in the control group (10.1%, 16/158, p = 0.01). Deeper tumor invasion was associated with a higher risk of post-ESD bleeding (5.3% in mucosal/submucosal layer 1 group vs. 12.5% in submucosal layer 2/muscularis propria group, p < 0.001). Multi-factor but not univariate analysis showed that proton pump inhibitor administration three times per day may be a better choice than twice per day. Increasing blood pressure under hemostasis during ESD to identify and coagulate potential bleeding spots could reduce the risk of delayed bleeding after gastric ESD.

Lung aeration and ventilation after general anesthesia in left lateral position: a prospective observational study using electrical impedance tomography

Endoscopic submucosal dissection (ESD) under general anesthesia in left lateral position may lead to transient impairment of pulmonary function. We used electrical impedance tomography (EIT), an increasingly implied non-invasive instrument for bedside real-time monitoring regional changes in ventilation, to assess the changes of regional lung aeration and ventilation in patients undergoing ESD. Twenty-two patients scheduled for elective ESD under mechanical ventilation in left lateral position were studied. We acquired 2-min EIT records at four time points: (M1) baseline, before induction of anesthesia, (M2) after the start of mechanical ventilation and before surgery, (M3) after surgery and before extubation, and (M4) after extubation and before leaving operation room, respectively. To quantify regional changes in lung ventilation, we calculated the ventilation proportion of left and right lung regions. Possible changes in lung aeration were detected by changes in end-expiratory lung impedance (EELI). Global inhomogeneity index (GI) was also analyzed. After tracheal intubation in the left lateral position, left lung showed a lower ventilation proportion (M1, 49.6% vs. M2, 36.2% P<0.05), a reduction in EELI {∆EELI -87 [-809; 253]} and a higher GI index value (M1, 0.29±0.09 vs. M2, 0.41±0.12, P<0.05), while right lung showed a higher ventilation proportion (M1, 50.4% vs. M2, 63.8%, P<0.05) and an increase in EELI {∆EELI 161 [-952; 1,905]}. During ESD operation, no changes in either regional ventilation distribution or GI index were observed. After extubation, the GI values in right and left lung were both returned to the level before anesthesia. In patients with left lateral position undergoing ESD, left lung was characterized by decreased ventilation and more inhomogeneity while right lung was opposite after intubation. ESD procedure with carbon dioxide insufflation did not lead to significant changes in either regional ventilation or homogeneity. And the change of lung inhomogeneity during ESD procedure is transient.

Predictors for operation time of endoscopic submucosal dissection for superficial gastric lesions

Objective To investigate the risk factors of operation time of endoscopic submucosal dissection (ESD) for superficial gastric lesions. Methods Clinicopathologic data of 193 patients (195 lesions) diagnosed with early gastric cancer preoperatively who received ESD in Beijing Friendship Hospital from January 2015 to December 2017 were retrospectively collected, including basic information (age, gender, body mass index, comorbidities), lesion characteristics (size, location, morphology), the operators′ experience of ESD, operation time, and postoperative pathology, etc. Univariate analysis was performed to find the risk factors of ESD operation time, and logistic regression analysis was performed on the factors with statistical differences in univariate analysis to find the independent risk factors of ESD operation time over 120 min. Results The mean age of the patients was 63.34±9.11 years. The median time of ESD operation was 120.00 (95.00, 165.00) min and the median size of the lesions was 1.50 (1.00, 2.38) cm. Early gastric cancer was diagnosed by postoperative pathology in 164 lesions (84.10%), among which 162 lesions (98.78%) achieved en bloc resection, and 148 lesions (90.24%) achieved curative resection. The gender (P=0.018), location(P 0.05). Multivariate analysis showed that the lesion located in cardia/fundus of stomach (OR=5.656, 95%CI: 2.291-13.964, P 2 cm in size (OR=2.761, 95%CI: 1.229-6.205, P=0.014) were independent risk factors for the operation time longer than 120 min. Conclusion Lesions located in the cardia/fundus, body of stomach and >2 cm in size are independent risk factors for long operation time of ESD. Key words: Risk factors; Stomach neoplasms; Superficial gastric lesions; Endoscopic submucosal dissection; Operation time

Risk factors of procedure time of endoscopic submucosal dissection for esophageal lesions

Objective To investigate risk factors of procedure time of endoscopic submucosal dissection (ESD) for treatment of esophageal lesions. Methods A total of 160 patients with single esophageal lesion who underwent ESD at department of gastroenterology, Beijing Friendship Hospital from January 2015 to October 2017 were enrolled. Medical information including general information (age and gender), and lesion’s characteristics (location, size, gross morphology, pathological type, differentiation degree, and depth of invasion), operators’experience, circumferential resection size, operation and anesthesia time were retrospectively collected. According to the operation time, the cases were divided into the long-term operation group (exceeded 120 min) and the short-time operation group (less than 120 min). The factors affecting the esophageal ESD operation time were analyzed by univariate and multivariate analysis. Results Among the 160 patients, 120 (75.0%) were men and 40 (25.0%) were women. The age was 62.65±8.48 years. The median (interquartile range) size of lesion was 1.70 (1.00, 2.65) cm. The median time of ESD was 113.54 (81.25, 168.75) min. Univariate analysis showed that age >65 years, the lesions of type Ⅱa+ Ⅱc/Ⅱc, lesion size >2 cm and >1/2 esophageal circumference resection were associated with a longer ESD operation time (P 0.05). Multivariate analysis showed that the type Ⅱa+ Ⅱc/Ⅱc (OR=2.47, 95%CI: 1.01-6.06, P=0.047), lesion size>2 cm (OR=3.41, 95%CI: 1.34-8.64, P=0.010) and > 1/2 esophageal circumference resection (OR=4.24, 95%CI: 1.62-11.11, P=0.030) were independent risk factors for the operation time of longer than 120 min. Conclusion Type Ⅱa+ Ⅱc/Ⅱc lesions, the lesion size >2 cm and the resection area >1/2 esophageal circumference were independent risk factors for a prolonged operation time of esophageal ESD procedure. Key words: Risk factors; Early esophageal cancers; Endoscopic submucosal dissection; Procedure time

Shared Autonomy of a Flexible Manipulator in Constrained Endoluminal Surgical Tasks

Automation in surgery is becoming more and more active in recent years. From the editorial of Science Robotics in 2017, there are six levels of autonomy and the existing tele-operation lies in level 0 (no autonomy). Although full autonomy would be fictional in the current moment, task/shared autonomy would be highly achievable. In endoluminal surgeries, surgeons rely on manual operation of flexible instruments for tissue manipulation and dissection. The techniques are difficult to learn, which makes them a good candidate for automation. In this letter, we introduce our work on shared autonomy of a flexible manipulator in simulated constrained endoluminal tasks, e.g., tissue dissection task in transanal total mesorectal excision and endoscopic submucosal dissection operations. During the procedure, the operator defines the dissection trajectory with a Novint Falcon device by marking via points. The dissection trajectory is dynamically planned based on the feedback from stereo endoscope system with consideration of the deformation of material. Furthermore, trajectory of the flexible manipulator is controlled by an adaptive controller with consideration of the possible collision between instruments and surrounding environment. This framework is validated by a mock up test with a three-degree-of-freedom flexible manipulator.

Development of chitosan/glycerophosphate/collagen thermo-sensitive hydrogel for endoscopic treatment of mucosectomy-induced ulcer

Endoscopic submucosal dissection (ESD) is a useful tool for the treatment of early gastric neoplasms, however post-ESD bleeding and perforation restrict its widespread application. In this study, we developed the chitosan/β-glycerophosphate/collagen (CS/GP/Col) thermo-sensitive systems to satisfy the requirements for the endoscopic treatment for ESD-induced ulcer. The results indicated that the addition of collagen to CS/GP system did not lead to remarkable changes on the physicochemical properties of the systems, which can transform from solution to hydrogels under physiological temperature within 90s, technically makes it suitable to be applied through catheter to gastric ulcer during ESD operation. Besides, hydrogels with high collagen concentration showed better biocompatibility, effectively protected L929, GES-1, HVSMC and CCD-18Co cells from acidic condition, induced more growth factors such as EGF, VEGF and FGF in those cells, and promoted coagulation. These results indicated that the CS/GP/Col thermo-sensitive hydrogel might be a promising biomaterial for the endoscopic treatment of ESD-induced ulcer, and further research can be carried out.

Therapeutic value of endoscopic submucosal dissection for polypus protrusion lesion on esophagogastric junction

Objective To evaluate the efficacy and safety of endoscopic submucosal dissection (ESD) in the treatment of patients with polypus protrusion lesion on esophagogastric junction(EGJ). Methods A retrospective analysis was made on the data of 111 cases (114 lesions) with EGJ polypus protrusion undergoing ESD. The main observation indicators included ESD resection rate, operation time, complication, and recurrence. Results The diameter of the 114 lesions was 1.0-6.0 cm (mean 2.47±0.80 cm). Among the lesions, 30 had smooth surface, 59 had congestion anabrosis, 11 had nodular rough, 3 were lobulated, 8 had villiform, 1 had slight anabrosis, and 2 had local dent. The postoperative pathology analysis showed 19 lesions were intraepithelial neoplasia and 2 were adenocarcinoma. The rate of neoplasia and cancerization was 18.42% (21/114). The monolithic resection rate of ESD was 100.0% (114/114), complete resection rate was 99.1% (113/114), complete healing resection rate was 97.4% (111/114). The mean operation time was 32.45±7.32 min (17.0-60.0 min). Tardive bleeding after operation occurred in 3 cases, perforation in operation occurred in 1 case, and all the 4 cases were successfully treated by endoscopy. After operation, 2 cases underwent additional surgical procedures. A total of 96 cases were followed-up, with average follow-up time of 28.8 months, and 1 patient (1.04%, 1/96) relapsed. Conclusion The intraepithelial neoplasia and cancerization rate caused by polypus protrusion lesion on EGJ is generally higher than prediction. ESD can monolithic resect lesions with higher complete healing resection rate, fewer complications, and lower recurrence rate. Key words: Polyp; Esophageal polypus; Gastric polyps; Cardiac polypus; Esophagogastric junction; Endoscopic submucosal dissection

Risk factors for post-colorectal endoscopic submucosal dissection (ESD) coagulation syndrome: a multicenter, prospective, observational study.

Background and study aims Colorectal cancer (CRC) is one of the most common neoplasms and endoscopic submucosal dissection (ESD) is an effective treatment for early-stage CRC. However, it has been observed that patients undergoing ESD often complain of pain, even if ESD has been successfully performed. Risk factors for such pain still remain unknown. The aim of this study was to explore the risk factors for post-colorectal ESD coagulation syndrome (PECS). Patients and methods This was a prospective multicenter observational trial (UMIN000016781) conducted in 106 of 223 patients who underwent ESD between March 2015 and April 2016. We investigated age, sex, tumor location, ESD operation time, lesion size, duration of hospitalization, and frequency of PECS. We defined PECS as local abdominal pain (evaluated on a visual analogue scale) in the region corresponding to the site of the ESD that occurred within 4 days of the procedure. Results PECS occurred in 15/106 (14.2 %), and 10 were women ( P = 0.01, OR: 7.74 [1.6 – 36.4]), 7 had lesions in the cecum ( P < 0.001, OR: 20.6 [3.7 – 115.2]), and 9 in whom ESD operation time was > 90 min ( P = 0.002, OR: 10.3 [2.4 – 44.6]). Frequency of deviation from the prescribed clinical path was significantly higher (47 % [7/15] vs. 2 % [2/91], P < 0.001, OR: 38.9 [6.9 – 219.6]), and hospital stay was significantly longer in the PECS group. Conclusions Female gender, location of lesion in the cecum, and ESD operation time > 90 minutes were significant risk factors independent of PECS. These findings are important to management of PECS.

Analysis of the Pathological Examination Results of 100 Colon Polyps Cases after EMR or ESD Operation

Aim: To study the characteristics of EMR (endoscopic mucosal resection) or ESD (endoscopic submucosal dissection) postoperative pathological examination of colonic polyps in different age groups, and the difference of pathological examination after EMR or ESD operation. Methods: A retrospective analysis was made of the EMR or ESD postoperative pathological data of 100 cases of colonic polyps patients in the Jingzhou Central Hospital digestive internal medicine. The time is from March 2016 to March 2018. Results: In 100 cases of EMR or ESD operation, there are 65 cases of young and middle-aged group. Pathological examination results include: 34 cases of adenomatous polyp, 18 cases of inflammatory polyp, 11 cases of benign tumors, 1 case of malignant tumor, 1 case of hyperplastic polyp. There are 35 cases of elderly group. Pathological examination results include: 27 cases of adenomatous polyp, 2 cases of inflammatory polyp, 2 cases of benign tumors, 4 cases of malignant tumor. 71 cases of complete EMR operation include: 51 cases of adenomatous polyp, 17 cases of inflammatory polyp, 3 cases of benign tumors; 29 cases of complete ESD operation include: 10 cases of adenomatous polyp, 3 cases of inflammatory polyp, 10 cases of benign tumors, 5 cases of malignant tumor, 1 case of hyperplastic polyp. Conclusion: For the pathological examination results after EMR or ESD operation, the proportion of inflammatory polyps in the young and middle-aged group was greater than that in the elderly group. The proportion of adenomatous polyps in the elderly group was larger than that in the young and middle-aged group. The proportion of adenomatous polyps in EMR was greater than that of ESD. The proportion of benign tumors and malignant tumors in ESD was greater than that of EMR. The difference has statistical significance.