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Background: The association between surgical performance ratings and clinical outcomes in robotic surgery is poorly understood. Additionally, no studies have reported on the relationship between the surgeon's initial case-skill evaluation and the learning curve in robot-assisted surgery. We evaluated whether an objective surgical technique evaluation score for initial robot-assisted radical prostatectomy (RARP) was associated with clinical outcomes and surgeons' learning curves., Methods: Six surgeons who were trained in and started to perform RARP at our institution were included. Anonymized, unedited videos of each surgeon's 10th RARP case were evaluated by three reviewers, using modified Objective Structured Assessment of Technical Skill (OSATS) scores. We then divided the surgeons into two groups on the basis of these OSATS scores. We retrospectively compared the clinical outcomes and learning curves of the console time of the two groups for consecutive RARPs, performed from March 2018 to July 2023., Results: We analyzed 258 RARPs (43 cases/surgeon), including 129 cases performed by high-OSATS score surgeons (18.2-19.3 points) and 129 cases performed by low-OSATS score surgeons (11.9-16.0 points). Overall, the high-OSATS score group had significantly shorter operation and console times than the low-OSATS score group did (both P < 0.01) and their patients' rate of continence recovery by 3 months post-RARP was significantly higher (P = 0.03). However, complications, blood loss, and positive margins did not differ between the groups (P = 0.08, P = 0.51, and P = 0.90, respectively). The high-OSATS score group had a significantly shorter console time than the low-OSATS score group did after the 11-20 cases., Conclusions: The OSATS score in early RARP cases can predict subsequent surgical outcomes and surgeons' learning curves., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Introduction Prolonged standing during surgery is a cause of musculoskeletal disorders in surgeons. Wearable chairs have reportedly reduced musculoskeletal strain effectively when used in industry. However, discomfort and instability issues may remain. This study examines whether using a wearable chair for surgical procedures imposes negative effects, such as mental or physical strain on surgeons prior to its clinical implementation. Methods This prospective cross-over study compared mental strain and subjective sensations in simulated suturing tasks with and without using Archelis®, a wearable chair (Archelis Inc, Yokohama, Japan). Six surgeons participated in the study. Mental strain was examined using heart rate variations calculated during tasks. Four subjective sensations (fatigue, comfort, balance, and workability) after each task and differences in body localized pain pre- and post-task were compared using a 10 centimetres (cm)-visual analog scale (VAS) score questionnaire. Results Results showed no significant differences in mental strain nor subjective sensations with or without the wearable chair. The mean VAS scores for all four subjective sensations with the wearable chair were relatively positive. There was a slight yet insignificant post-task increase in VAS mean scores for body-localized pain in the lower legs. Conclusions Significant negative effects on surgeons from the wearable chair were not observed during simulated suturing procedures. This demonstrates no major barriers in the initial phases of wearable chairs integration into the surgery environment., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. The Institutional Ethics Committee of Jichi Medical University issued approval A18-158. We hereby notify you that based on the results of the review by the University Ethics Review Committee for Clinical Research, etc., we have decided to permit you to conduct research on the proposal for which an application was submitted on February 7, 2019. Issue Title: Sensitivity measurement during the use of medical simulation based on psychological, physiological, and behavioral indicators. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Shinohara et al.)

The advent of Artificial Intelligence (AI)-based object detection technology has made identification of position coordinates of surgical instruments from videos possible. This study aimed to find kinematic differences by surgical skill level. An AI algorithm was developed to identify X and Y coordinates of surgical instrument tips accurately from video. Kinematic analysis including fluctuation analysis was performed on 18 laparoscopic distal gastrectomy videos from three expert and three novice surgeons (3 videos/surgeon, 11.6 h, 1,254,010 frames). Analysis showed the expert surgeon cohort moved more efficiently and regularly, with significantly less operation time and total travel distance. Instrument tip movement did not differ in velocity, acceleration, or jerk between skill levels. The evaluation index of fluctuation β was significantly higher in experts. ROC curve cutoff value at 1.4 determined sensitivity and specificity of 77.8% for experts and novices. Despite the small sample, this study suggests AI-based object detection with fluctuation analysis is promising because skill evaluation can be calculated in real time with potential for peri-operational evaluation., (© 2024. The Author(s).)

Introduction: In robotic surgery, studies on providing tactile feedback to users are ongoing. However, the accuracy of the subjective sensations of surgeons, as users, has been largely unassessed. This study aimed to assess the validity of surgeons' subjective evaluations of scissors resistance through interindividual, inter-surgeon, and objective evaluations. Furthermore, in this study, we explored the possibility of using nitriding to increase the hardness of the scissors and assessed changes in subjective resistance values before and after nitriding using this approach., Method: Five surgeons conducted validation of five curved surgical scissors (145 mm; Arakawa Seisakujyo Co., Ltd., Tokyo, Japan) and assessed their subjective resistance using a scale from 0 to 10, where a rating of 10 signified significant resistance impeding the scissors' closure. The temporal changes in subjective resistance values, from maximum open to close, were graphically recorded. To demonstrate the reproducibility of subjective resistance values, the subjective resistance values of the same control scissors were measured at intervals of at least two weeks, and the correlation coefficient was calculated. To analyze the closing characteristics of subjective resistance values between different pairs of scissors, the effect of scissor type and scissor closure position was compared as two independent variables using a two-factor analysis of variance. A comparative evaluation was conducted to assess the frictional properties of scissors after nitriding, comparing the subjective assessment by surgeons with the objective assessment using a digital force gauge., Results: The correlation coefficient of subjective resistance values measured by surgeons demonstrated a high reproducibility of 0.746. A two-factor analysis of variance conducted on subjective resistance values demonstrated the presence of a primary effect for the sample factor (scissors), as well as for the position factor (closing process), with the additional observation of the interaction between these two factors. The results from the two-factor analysis of variance above provide evidence supporting the validity of the subjective resistance measurements. There was a significant increase in subjective resistance after the nitriding process. The graph of subjective resistance values and objective resistance values showed similarity., Conclusions: The surgeons' subjective assessment of scissors resistance showed high reproducibility and validity, as evidenced by distinguishable differences in scissor movement interactions and pre- and post-nitriding resistance. Further studies are warranted to expand on these findings., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2024, Ota et al.)

Introduction During surgery, surgeons intuitively recognize when they are using dull scissors and find them difficult to use. The purpose of this study was to objectively evaluate the physical characteristics of scissors and the comfort reported by surgeons to develop objective quality control standards for scissors used in surgery. Methods Sensory and measurement tests were conducted to evaluate the comfort and physical characteristics of ten pairs of Cooper scissors. As a sensory test, thirty-one volunteer surgeons opened and closed the scissors and selected three that felt comfortable and three that were uncomfortable. The results were scored. For measurement, a load was applied to the handle of the scissors. The load pressure and displacement of the width between each handle when the scissors were closed were measured. Results A strong negative correlation was found between the total comfort score and the mean load value between sensory and measurement tests (r=-0.717, p=0.0195). The correlation between the total score and the change in load at the tip showed a moderate negative correlation (r=-0.687, p=0.0282). Multiple regression analysis showed that the change in load at the tip was an independent factor affecting the total score. Conclusions Surgeons consider scissors with a low mean load required to close the scissors and a small change in load at the tip to be comfortable. The mean load on scissors and the change in load at the tip should be considered in the development of quality control standards for scissors used in surgery., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2024, Ota et al.)

Background: Although metformin reduces the risk of cancer-related mortality in patents with type 2 diabetes, the mechanism of its anti-cancer effects has not been fully understood., Method: Impact of metformin on survival was examined in patients who underwent curative colectomy for colorectal cancer (CRC). The effects of metformin in neutrophil extracellular traps (NETs) were examined with in-vitro experiments and multiplex immunohistochemistry of surgically resected CRC specimens., Results: Prior intake of metformin prolonged relapse-free (P = 0.036) and overall survival (P = 0.041) in 289 patients with T2DM to the comparable levels to those of 1576 non-diabetic patients. Metformin reduced the production of NETs stimulated with lipopolysaccharide or HT-29 colon cancer cells to 60% of control. Neutrophils markedly suppressed the chemotactic migration of activated T cells in an NET-dependent manner, which was reversed by metformin treatment up to approximately half of the migration without neutrophils. Immunohistochemical analysis revealed a significant association between metformin intake and a reduction in the numbers of tumor-associated neutrophils (TANs) and NETs. Simultaneously, metformin intake was found to increase the presence of CD3(+) and CD8(+) tumor-infiltrating T cells (TILs), particularly at the tumor-invasion front, especially in areas with fewer TANs and NETs., Conclusion: Metformin suppresses the diabetes-associated enhancement of NET formation, which can augment the infiltration of TILs in CRC tissues. The anti-tumor effect of metformin in patients with T2DM may be, at least partly, attributable to the inhibition of NETs., (© 2023. The Author(s).)

Introduction Postoperative pancreatic fistula (POPF) is a critical complication occurring with a high incidence after distal pancreatectomy. To minimize the risk of POPF, we developed an innovative pancreas ligation device capable of closing the pancreatic stump without causing traumatic injury to the pancreatic duct and artery. We conducted an ex vivo follow-up study to compare the pressure resistance of the pancreas ligation device with that of a regular linear stapler. Materials and methods The pancreases were excised from 20 pigs and divided into two groups: ligation group ( n = 10) and stapler group ( n = 10). Distal pancreatectomy was performed, and the pancreatic stump was closed using either a pancreas ligation device or a regular linear stapler. The main pancreatic duct was cannulated with a 4-French catheter connected to a cannula and syringe filled with contrast medium. Using fluoroscopy detection, pressure resistance was defined as the maximum pressure without leakage from the pancreatic stump. Results No significant differences were found between the two groups regarding sex, age, body weight, or pancreatic thickness. In the ligation group, no leakage was observed at the stump in any pancreas. However, in the stapler group, six of 10 pancreases showed leakage at the staple line or into the parenchyma. Pressure resistance was significantly higher in the ligation group than in the stapler group (median: 42.8 vs. 34.3 mmHg, P = 0.023). Conclusions These findings suggest the effectiveness of a pancreas ligation device in reducing the incidence of POPF after distal pancreatectomy. Our ligation device is expected to be a useful alternative to a linear stapler for pancreatic stump closure., Competing Interests: United States Patent; patent no.: US 11337704; date of patent: May 24, 2022; Tool for Treating Excised End of Body Organ; applicant: Jichi Medical University, Tokyo (JP); inventor: Yuji Kaneda, Shimotsuke (JP), (Copyright © 2023, Kaneda et al.)

To maintain the effectiveness of the training (1st-Training Session: 1st-TS) to accurate describe facts in the medical incident reports (IRs) in Japanese, a refresher TS was designed and its effectiveness was examined. First, textual analysis showed that IRs' accuracy significantly decreased six months after the 1st-TS. Based on this result, the refresher TS was designed and conducted with 64 residents. To verify the refresher TS' effectiveness, IRs after the 1st-TS, six months later, and after the refresher TS were compared via text analysis. The results showed that the refresher TS restored the description rate of patient's background, safety check procedures, original work procedures, information on equipment used, reporter's actions, and post-incident response. The questionnaire was also administered and showed that the refresher TS contributed to residents' motivation to learn about IRs. In conclusion, the refresher TS contributed to sustaining the effect of the 1st-TS on accurately describing IRs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Introduction: Computer-aided diagnostic systems are emerging in the field of gastrointestinal endoscopy. In this study, we assessed the clinical performance of the computer-aided detection (CADe) of colonic adenomas using a new endoscopic artificial intelligence system., Methods: This was a single-center prospective randomized study including 415 participants allocated into the CADe group (n = 207) and control group (n = 208). All endoscopic examinations were performed by experienced endoscopists. The performance of the CADe was assessed based on the adenoma detection rate (ADR). Additionally, we compared the adenoma miss rate for the rectosigmoid colon (AMRrs) between the groups., Results: The basic demographic and procedural characteristics of the CADe and control groups were as follows: mean age, 54.9 and 55.9 years; male sex, 73.9% and 69.7% of participants; and mean withdrawal time, 411.8 and 399.0 s, respectively. The ADR was 59.4% in the CADe group and 47.6% in the control group (p = 0.018). The AMRrs was 11.9% in the CADe group and 26.0% in the control group (p = 0.037)., Conclusion: The colonoscopy with the CADe system yielded an 11.8% higher ADR than that performed by experienced endoscopists alone. Moreover, there was no need to extend the examination time or request the assistance of additional medical staff to achieve this improved effectiveness. We believe that the novel CADe system can lead to considerable advances in colorectal cancer diagnosis., (© 2023 S. Karger AG, Basel.)

Objective: A system to provide feedback for laparoscopic training using an online conferencing system during the COVID-19 pandemic was developed. The purpose of this study is to evaluate this system from the trainer perspective., Design: A procedural feedback system using an online conferencing system was devised., Setting: Surgical training was observed using an online conferencing system (Zoom). Feedback was provided while viewing suture videos which are, as a feature of this system, pre-recorded. Feedback was then recorded. Trainer comments were then converted into text, summarized as feedback items, and sorted by suture phase which facilitates reflection. Trainers completed a questionnaire concerning the usability of the online feedback session., Results: Eleven trainers were selected. Physicians had an average experience of 21.9 ± 5.9 years (mean ± standard deviation). The total number of feedback items obtained by classifying each phase was 32. Based on questionnaire results, 91% of trainers were accustomed to the use of Zoom, and 100% felt that online procedural education was useful. In questions regarding system effectiveness, more than 70% of trainers answered positively to all questions, and in questions about efficiency, more than 70% of trainers answered positively. Only 55% of the trainers felt that this system was easy to use, but 91% were satisfied as trainers., Conclusions: The results of the questionnaire suggest that this system has high usability for training. This online system could be a useful tool for providing feedback in situations where face-to-face education is difficult., Competing Interests: The authors declare no conflict of interest., (© 2022 The Author(s).)

Introduction: An eyeglass gaze camera and a skeletal coordinate camera without sensors attached to the operator's body were used to monitor gaze and movement during a simulated surgical procedure. These new devices have the potential to change skill assessment for laparoscopic surgery. The suitability of these devices for skill assessment was investigated., Material and Methods: Six medical students, six intermediate surgeons, and four experts performed suturing tasks in a dry box. The tip positions of the instruments were identified from video recordings. Performance was evaluated based on instrument movement, gaze, and skeletal coordination., Results: Task performance time and skeletal coordinates were not significantly different among skill levels. The total movement distance of the right instrument was significantly different depending on the skill level. The SD of the gaze coordinates was significantly different depending on skill level and was less for experts. The expert's gaze stayed in a small area with little blurring., Conclusions: The SD of gaze point coordinates correlates with laparoscopic surgical skill level. These devices may facilitate objective intraoperative skill evaluation in future studies., (© 2022 Asia Endosurgery Task Force and Japan Society of Endoscopic Surgery and John Wiley & Sons Australia, Ltd.)

We assessed whether training on writing readable and accurate medical incident reports (IRs) improves the quality of fact description. In this training, 124 residents created fictional IRs. We provided tips, including using When, Where, Who, What, Why, How. We compared the fictional IRs with and without tips, and the trainees' and non-trainees' IRs submitted in the first five months after training. Results indicated that the subject words in IRs were more clarified and the readability was improved. The fictional IRs using tips were more accurate, with increased descriptions of the patient's background, reporter's actions, team members' actions and conversations, safety check procedures, result of the error, and post-incident response. The reporter's actions, work procedures, and environment were more clarified in the trainees' IRs than in the non-trainees' IRs. This training may help analysts comprehend the sequence of and underlying factors for reporter's actions based on IRs., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Introduction: While exposure of surgeons and other staff to surgical smoke is an increasing health risk concern, there is a similar risk for users in surgical simulation and training. This study was undertaken to determine the chemical composition of smoke produced from a novel training model, Versatile Training Tissue (VTT), which is used for surgical simulation and training, and to compare this with smoke from a chemosynthetic model and porcine muscle and liver., Methods: A variety of models (VTT, polyvinyl alcohol, porcine muscle and liver) were prepared and cauterized. Identification of chemical substances in smoke was performed using gas chromatography-mass spectrometry. Quantitative instrumental analysis was implemented with gas chromatography-mass spectrometry and high-performance liquid chromatography. A convenient analysis was performed with a general smoke tube kit., Results: The main chemical components of smoke produced from VTT models include water and carbon dioxide. A small number of organic compounds were detected. Versatile Training Tissue models produced smoke with fewer compounds than smoke from a chemosynthetic model or porcine muscle., Conclusions: The concentration of organic compounds from VTT models is considered to be below relevant health risk limits and lower than from polyvinyl alcohol and porcine muscle models. Although porcine liver smoke contains less of the main organic compounds of concern than a KM, it contains potentially hazardous nitrile compounds that are absent in KM smoke. Therefore, surgical simulation and training with VTT models should be considered relatively safe for trainees., Competing Interests: G.M. and S.T. are employees of KOTOBUKI Medical, Inc. The other authors declare no conflict of interest., (Copyright © 2021 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the Society for Simulation in Healthcare.)

Dipeptidyl peptidase IV inhibitor (DPP-4i) has been shown to act either as a promoter or as a suppressor for cancer. Although epidemiologic studies suggest that DPP-4i does not correlate with the development of malignancies, its effects on cancer metastases are controversial. We evaluated the impact of DPP-4i on postoperative outcomes of the diabetic patients with colorectal cancer and microscopic features of the resected tumors. In 260 consecutive patients with type 2 diabetes mellitus (T2DM) who underwent curative resection of colorectal cancer, the correlation between DPP-4i use and prognosis was retrospectively examined. Expression of Zeb1 on tumor cells and density of infiltrating immune cells were quantitatively evaluated with multicolor IHC in 40 tumors from DPP-4i users, 40 tumors from propensity score-matched users, and 40 tumors from nonusers. Postoperative disease-free survival (DFS) was significantly lower in 135 patients treated with DPP-4i compared with 125 nontreated patients [5-year DFS, 73.7% vs. 87.4%; HR, 1.98; 95% confidence interval (CI), 1.05-3.71; P = 0.035]. IHC revealed that the number of Zeb1 + tumor cells increased in tumors from DPP-4i-treated patients than tumors from nonusers ( P < 0.01). The densities of CD3 + and CD8 + T cells were significantly lower in tumors from DPP-4i users ( P < 0.01) with decreased density of tertiary lymphoid structures ( P < 0.001). However, the density of M2-type tumor-associated macrophages with CD68 + CD163 + phenotypes was significantly higher ( P < 0.01) in tumors from DPP-4i users. Exposure of colorectal cancer to DPP-4i may accelerate epithelial-to-mesenchymal transition (EMT) creating a tumor-permissive immune microenvironment, which might impair the outcomes of the patients with colorectal cancer and T2DM., Significance: DPP-4i has been shown to enhance the antitumor effects of immunotherapy. However, we found that DPP-4i significantly impairs the outcomes of patients with colorectal cancer who underwent curative resection, possibly through acceleration of EMT and creation of a tumor-permissive immune microenvironment. This suggests that DPP-4i must be used with caution until its safety is fully confirmed by further studies of the mechanistic effects on existing cancers in humans., Competing Interests: H. Yamaguchi reports grants from Taiho Pharmaceutical, Co., Ltd, Nippon Kayaku Co., Ltd., Eli Lilly Japan K.K., Chugai Pharmaceutical Co., Ltd., and grants from ONO Pharmaceutical Co., Ltd. outside the submitted work. No other disclosures were reported., (© 2021 The Authors; Published by the American Association for Cancer Research.)

Objective: To evaluate the acceptability of using a static wearable chair for patients requiring rehabilitation., Methods: The acceptability of use of a static wearable chair during rehabilitation was assessed via static balance and subjective evaluation of 7 healthy subjects and 3 patients during standing training. Participants performed 1 standing task in free mode (in which the knee could bend freely) and 1 in support mode (in which the user could sit on the wearable chair with the knee slightly bent) for 3 min. For balance evaluation, the skeletal coordinates were measured. For subjective evaluation, a visual analogue scale questionnaire was administered before and after each task., Results: Balance assessment revealed that patients had less head sway during support, whereas subjective evaluation showed that the device support created a positive psychological state in terms of stability, comfort, satisfaction, interest in usage, and motivation for rehabilitation. However, patients reported feeling strangeness, fear, or restraint during support., Conclusion: The static wearable chair improved the static balance of 3 patients and created a more positive psychological state. Use of the device is considered acceptable for use with rehabilitation patients. However, patients might feel strangeness, fear, and restraint during support. Familiarization with the static wearable chair may make it more acceptable among rehabilitation patients., Competing Interests: This study was supported by Archelis Inc., with the free use of Archelis®. This company has had no influence on the data interpretation and the final conclusions., (© 2021 Journal of Rehabilitation Medicine.)

In this study, the relationship between gaze patterns, task duration, and years of experience, which are commonly used to define and evaluate expert surgeons in laparoscopic surgery, was identified. Ten surgeons with 1-28 years of experience and six inexperienced students were included. Subjects used forceps to repeat the task of suturing a suture pad. Each subject wore an eye-marking recorder, and gaze points were recorded and analyzed. No significant relationship between task duration and gaze pattern was observed. However, there was a significant relationship between a surgeon's years of experience and the percentage of time spent gazing at the forceps. Subjects with more years of experience operated without looking at the forceps and fixed their gaze on the operational target. Therefore, when analyzing laparoscopic gazing patterns, it may be more appropriate to define an "expert" based on the years of experience rather than task duration., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Introduction Although new techniques and devices have been introduced, the incidence of postoperative pancreatic fistula (POPF) after distal pancreatectomy remains high. To reduce the risk of POPF, we developed an innovative ligation band and conducted this pilot study to assess the possibility of reducing the incidence of POPF and pancreatic necrosis after distal pancreatectomy. Methods Distal pancreatectomy was performed in three pigs. In two animals, ligation of the pancreas was performed while maintaining arterial blood flow to the stump, and in one animal, the arterial blood flow was occluded. After ligation, the pancreas was sharply divided. Animals were sacrificed seven days later, and the remnant pancreas was assessed histologically. POPF was defined as amylase in ascites > 3x the preoperative serum amylase level. The following equation was used to quantify the extent of necrotic tissue: necrotic tissue residual rate = necrotic tissue area/ cross-sectional area. Results All animals survived, and no POPF developed. For two animals in which arterial blood flow to the stump was maintained, necrotic tissue residual rates at the ligation line were 24% and 31%. At the pancreatic stump, necrotic tissue residual rates were 37% and 50%. In the animal in which arterial blood flow to the stump was occluded, the necrotic tissue residual rate at the ligation line was 83% and that at the pancreatic stump was 78%, both higher than that in animals in which arterial blood flow was maintained. In all animals, there was no injury to pancreatic tissue at the ligation line. Conclusion The pancreas ligation band can potentially prevent POPF after distal pancreatectomy by atraumatic ligation, and the band ligates the pancreatic stump while maintaining arterial blood flow and limiting pancreatic necrosis., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2021, Kaneda et al.)

Surgeons have increased physical stress during laparoscopic surgery due to operative site constraints. We developed a wearable device to reduce the physical stress on surgeons' lower extremities. The device mechanically facilitates maintaining a near-upright posture. The surgeon's knees are gently bent by a knee-joint locking mechanism, and fixing and releasing are performed independently on each side. The subjects were one female and two male surgeons, who wore the device during laparoscopic inguinal hernia repair or high anterior resection. Surface electromyogram (EMG) was conducted for both iliopsoas muscles. Control values were determined with the subject not wearing the device. Participants completed a post-procedure questionnaire. With the device, EMG activity had a tendency to decrease in the left iliopsoas muscle (P = .055), but it changed little on the right (P = .406). The post-procedure questionnaire showed an overall positive impression, although subjects reported some difficulty walking. This device decreases EMG activity and may improve a surgeon's work environment., (© 2020 Japan Society for Endoscopic Surgery, Asia Endosurgery Task Force and John Wiley & Sons Australia, Ltd.)

Background: Helicobacter pylori (H. pylori) eradication is required to reduce incidence related to gastric cancer. Recently, it was found that even after the successful eradication of H. pylori, an increased, i.e., moderate, risk of gastric cancer persists in patients with advanced mucosal atrophy and/or intestinal metaplasia. This study aimed to develop a computer-aided diagnosis (CAD) system to classify the status of H. pylori infection of patients into three categories: uninfected (with no history of H. pylori infection), currently infected, and post-eradication., Methods: The CAD system was based on linked color imaging (LCI) combined with deep learning (DL). First, a validation dataset was formed for the CAD systems by recording endoscopic movies of 120 subjects. Next, a training dataset of 395 subjects was prepared to enable DL. All endoscopic examinations were recorded using both LCI and white-light imaging (WLI). These endoscopic data were used to develop two different CAD systems, one for LCI (LCI-CAD) and one for WLI (WLI-CAD) images., Results: The diagnostic accuracy of the LCI-CAD system was 84.2% for uninfected, 82.5% for currently infected, and 79.2% for post-eradication status. Comparisons revealed superior accuracy of diagnoses based on LCI-CAD data relative based on WLI-CAD for uninfected, currently infected, and post-eradication cases. Furthermore, the LCI-CAD system demonstrated comparable diagnostic accuracy to that of experienced endoscopists with the validation data set of LCI., Conclusions: The results of this study suggest the feasibility of an innovative gastric cancer screening program to determine cancer risk in individual subjects based on LCI-CAD.

Accumulating evidence suggests that metformin reduces the incidence and mortality of colorectal cancer (CRC). However, underlying mechanisms have not been fully clarified. The aim of this study was to examine the pathological characteristics of resected CRC from patients treated with metformin for type 2 diabetes mellitus (DM). In total, 267 patients with DM underwent curative colectomy for Stage I-III CRC and 53 (19.9%) patients had been treated medically including metformin. Pathological N-stage was significantly lower in metformin-treated patients (P < .05) with prolonged disease-free survival (DFS) (P < .05). Immunohistochemistry showed that the densities of CD3(+) and CD8(+) tumor-infiltrating lymphocytes (TILs) in the invasive front area were significantly higher in 40 patients treated with metformin compared with propensity score matched cases without metformin (P < .05). The density of tertiary lymphoid structures (TLS) in tumor stroma was markedly increased in metformin-treated patients (P < .001). In those tumors, there were more CD68(+) tumor-associated macrophages (TAM) infiltrated (P < .05), while the ratio of CD163(+) M2-phenotype was markedly reduced (P < .001). Stromal fibrosis tended to be suppressed by metformin intake (P = .051). These findings suggested that metformin drastically changes the characteristics of infiltrating immune cells in CRC and reprograms the tumor microenvironment from immunosuppressive to immunocompetent status, which may lead to suppression of microscopic tumor spread and improve the outcomes of patients with CRC and type 2 DM., (© 2020 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.)

Objectives: To evaluate the effect of simulator fidelity on procedure skill training through a review of existing studies., Methods: MEDLINE, OVID and EMBASE databases were searched between January 1990 and January 2019. Search terms included "simulator fidelity and comparison" and "low fidelity" and "high fidelity" and "comparison" and "simulator". Author classification of low- and high-fidelity was used for non-laparoscopic procedures. Laparoscopic simulators are classified using a proposed schema. All included studies used a randomized methodology with two or more groups and were written in English. Data was abstracted to a standard data sheet and critically appraised from 17 eligible full papers., Results: Of 17 studies, eight were for laparoscopic and nine for other skill training. Studies employed evaluation methodologies, including subjective and objective measures. The evaluation was conducted once in 13/17 studies and before-after in 4/17. Didactic training only or control groups were used in 5/17 studies, while 10/17 studies included two groups only. Skill acquisition and simulator fidelity were different for the level of training in 1/17 studies. Simulation training was followed by clinical evaluation or a live animal evaluation in 3/17 studies. Low-fidelity training was not inferior to training with a high-fidelity simulator in 15/17 studies., Conclusions: Procedure skill after training with low fidelity simulators was not inferior to skill after training with high fidelity simulators in 15/17 studies. Some data suggest that the effectiveness of different fidelity simulators depends on the level of training of participants and requires further study.

Laparoscopic surgery requires highly trained skills to manipulate the laparoscopic instruments. The effectiveness and efficiency of manipulation training are expected to increase by quantitatively evaluating how a series of trainee's manipulations are different from those conducted by skilled surgeons and providing feedback. However, such detailed feed- back is not available because adequate measurement systems have not been proposed to measure the precise forces applied to suture training pads without disturbing the delicate manipulations. Therefore, we proposed a sensorized suture training pad satisfying the above requirements. Three surgical residents participated in an experiment to measure time sequences of three-dimensional forces applied to the pad when executing a transfixion suture. As a result, the differences in manipulation patterns among the residents were found by dividing the transfixion operation based on the sequential force data and recorded videos.

Background: We developed a surgical knee rest (SKR) that can be used to decrease the stress placed on the lower half of the body when surgeons work in the standing position. We tested the effectiveness of this device in the context of laparoscopic surgery., Material and Methods: Five healthy, right-handed male surgeons participated, and we recorded surface electromyography (sEMG) signals from the two heads of the left and right gastrocnemius (Gc) muscles during laparoscopic resections of colorectal cancer. The outcome variable was the percentage of maximum Gc muscle effort generated, reported as percent maximal isometric voluntary contraction (%MVC), and this variable was compared between surgeries performed with and without use of the SKR. Assessment covered the first 100 min of surgery, subdivided into two 50-min periods., Results: Mean %MVC of the left Gc muscle for the full 100-min test period was significantly decreased when the SKR was used (p = .027, vs. SKR not used). Notably, mean %MVC of both Gc muscles was significantly decreased during the first 50 min of surgery (p = .008 and p = .0046)., Conclusion: The SKR is useful for decreasing physical stress incurred by laparoscopic surgeons when working in the standing position.

Objective: This study aimed to use convolutional neural network (CNN), a deep learning software, to assist in cT1b diagnosis., Methods: This retrospective study used 190 colon lesion images from 41 cases of colon endoscopies performed between February 2015 and October 2016. Unenhanced colon endoscopy images (520 × 520 pixels) with white light were used. Images included 14 cTis cases with endoscopic resection and 14 cT1a and 13 cT1b cases with surgical resection. Protruding, flat, and recessed lesions were analyzed. AlexNet and Caffe were used for machine learning. Fine tuning of data to increase image numbers was performed. Oversampling for the training images was conducted to avoid impartiality in image numbers, and learning was carried out. The 3-fold cross-validation method was used. Sensitivity, specificity, accuracy, and area under the curve (AUC) values in the receiver operating characteristic curve were calculated for each group., Results: The results were the average of obtained values. With CNN learning, cT1b sensitivity, specificity, and accuracy were 67.5, 89.0, and 81.2%, respectively, and AUC was 0.871., Conclusion: Quantitative diagnosis is possible using an endoscopic diagnostic support system with machine learning, without relying on the skill and experience of endoscopists. Moreover, this system could be used to objectively evaluate endoscopic diagnoses., (© 2018 S. Karger AG, Basel.)

Background: Deep learning is a type of artificial intelligence (AI) that imitates the neural network in the brain. We generated an AI to diagnose Helicobacter pylori ( H. pylori ) infection using blue laser imaging (BLI)-bright and linked color imaging (LCI). The aim of this pilot study was to establish an AI diagnosing system that predicts H. pylori infection status using endoscopic images to improve the accuracy and productivity of endoscopic examination., Methods: A total of 222 enrolled subjects (105 H. pylori -positive) underwent esophagogastroduodenoscopy and a serum test for H. pylori IgG antibodies. During esophagogastroduodenoscopy, an endoscopist sequentially took 3 still images of the lesser curvature of the stomach using white light imaging (WLI), BLI-bright, and LCI. EG-L580NW endoscopic equipment (FUJIFILM Co., Japan) was used for the study. The specifications of the AI were as follows: operating system, Linux; neural network, GoogLeNet; framework, Caffe; graphic processor unit, Geforce GTX TITAN X (NVIDIA Co., USA)., Results: The area under the curve (AUC) on receiver operating characteristics analysis was 0.66 for WLI. In contrast, the AUCs of BLI-bright and LCI were 0.96 and 0.95, respectively. The AUCs obtained for BLI-bright and LCI were significantly larger than those for WLI (P<0.01)., Conclusions: The results demonstrate that the developed AI has an excellent ability to diagnose H. pylori infection using BLI-bright and LCI. AI technology with image-enhanced endoscopy is likely to become a useful image diagnostic tool., Competing Interests: Conflict of Interest: None

Background and Study Aims: Helicobacter pylori (HP)-associated chronic gastritis can cause mucosal atrophy and intestinal metaplasia, both of which increase the risk of gastric cancer. The accurate diagnosis of HP infection during routine medical checks is important. We aimed to develop a convolutional neural network (CNN), which is a machine-learning algorithm similar to deep learning, capable of recognizing specific features of gastric endoscopy images. The goal behind developing such a system was to detect HP infection early, thus preventing gastric cancer., Patients and Methods:  For the development of the CNN, we used 179 upper gastrointestinal endoscopy images obtained from 139 patients (65 were HP-positive: ≥ 10 U/mL and 74 were HP-negative: < 3 U/mL on HP IgG antibody assessment). Of the 179 images, 149 were used as training images, and the remaining 30 (15 from HP-negative patients and 15 from HP-positive patients) were set aside to be used as test images. The 149 training images were subjected to data augmentation, which yielded 596 images. We used the CNN to create a learning tool that would recognize HP infection and assessed the decision accuracy of the CNN with the 30 test images by calculating the sensitivity, specificity, and area under the receiver operating characteristic (ROC) curve (AUC)., Results:  The sensitivity and specificity of the CNN for the detection of HP infection were 86.7 % and 86.7 %, respectively, and the AUC was 0.956., Conclusions:  CNN-aided diagnosis of HP infection seems feasible and is expected to facilitate and improve diagnosis during health check-ups.

Purpose: By integrating locally operated small surgical robots in a sterilized area, a surgeon can perform safe and accurate robotically assisted laparoscopic surgery. At present, there is no locally operated compact forceps robot that can operate within a small space while providing a wide working area on the abdominal wall. In the present study, a new spherical-coordinate manipulator with a linear telescopic rail and two circular telescopic rails that can act as a third arm for the surgeon has been developed., Methods: A compact locally operated detachable end-effector manipulator (LODEM) was developed. This manipulator uses circular telescopic rails with linkage mechanisms for the yaw and pitch axes, and a linear telescopic rail for the insertion/extraction axis is attached to forceps. The dimensions of the manipulator are [Formula: see text] when contracted and [Formula: see text] when expanded. The positional accuracy, mechanical deflection, and backlash of the prototype were evaluated while performing simulated in vivo laparoscopic surgery., Results: The positional accuracy, deflection, and backlash of the telescopic rail mechanism were 2.1, 1.8, and 5.1 mm, respectively. The manipulator could successfully handle the target and maintain stability, while the arms of the endoscope specialist were free from collisions with the manipulator during an in vivo laparoscopic surgery., Conclusions: A compact LODEM was designed to facilitate minimally invasive, robotically assisted laparoscopic surgery by a doctor working near the patient. This device could be used for such applications.

Background and study aims  We have developed a combined laparoscopic and luminal endoscopic surgery technique for resection of gastric submucosal tumors (SMTs) that can be performed without excessive resection of the stomach. In a multicenter retrospective study we aimed to evaluate the feasibility and safety of laparoscopic and endoscopic cooperative surgery (LECS) for gastric SMT resection. Patients and methods  Between October 2007 and December 2011, 126 patients with gastric SMTs underwent LECS at 8 institutions. Patient demographics, tumor histopathologic characteristics, and operative and follow-up data were reviewed. Results  16 tumors (12.7 %) were located in the upper third of the stomach, 88 (69.8 %) in the middle third, 5 (4.0 %) in the lower third, and 17 (13.5 %) at the esophagogastric junction. The mean (standard deviation [SD]) operation time for LECS was 190.2 (66.8) min, with a mean estimated blood loss of 15.1 (38.6) mL. In 2 cases (1.6 %), the procedure was converted to open surgery because of intra-abdominal adhesions or stenosis. Morbidity was found in 6 cases (4.8 %), including 2 leakage, 2 gastric stasis, 1 fever, and 1 cystitis. Histologically, a gastrointestinal stromal tumor (GIST) was found in 86 (68.3 %) cases. The median follow-up period was 54.7 months; no local or distant tumor recurrence was observed and all patients were alive. Conclusions  LECS proved to be a safe and feasible procedure for the resection of gastric SMTs, with a reasonable operation time, low bleeding, and an acceptable complication rate in this multicenter study in Japan., (© Georg Thieme Verlag KG Stuttgart · New York.)

Aim: To investigate the detrimental impact of loss of reservoir capacity by comparing total gastrectomy (TGRY) and distal gastrectomy with the same Roux-en-Y (DGRY) reconstruction. The study was conducted using an integrated questionnaire, the Postgastrectomy Syndrome Assessment Scale (PGSAS)-45, recently developed by the Japan Postgastrectomy Syndrome Working Party., Methods: The PGSAS-45 comprises 8 items from the Short Form-8, 15 from the Gastrointestinal Symptom Rating Scale, and 22 newly selected items. Uni- and multivariate analysis was performed on 868 questionnaires completed by patients who underwent either TGRY ( n = 393) or DGRY ( n = 475) for stage I gastric cancer (52 institutions). Multivariate analysis weighed of six explanatory variables, including the type of gastrectomy (TGRY/DGRY), interval after surgery, age, gender, surgical approach (laparoscopic/open), and whether the celiac branch of the vagus nerve was preserved/divided on the quality of life (QOL)., Results: The patients who underwent TGRY experienced the poorer QOL compared to DGRY in the 15 of 19 main outcome measures of PGSAS-45. Moreover, multiple regression analysis indicated that the type of gastrectomy, TGRY, most strongly and broadly impaired the postoperative QOL among six explanatory variables., Conclusion: The results of the present study suggested that TGRY had a certain detrimental impact on the postoperative QOL, and the loss of reservoir capacity could be a major cause., Competing Interests: Conflict-of-interest statement: The authors declare no conflicts of interests related to the publication of this study.

Background/aims: Totally laparoscopic distal gastrectomy (TLDG) has become a feasible and safe surgical option for early gastric cancer. However, determining the transection line of the stomach without palpation is still difficult. This study aimed to assess the efficacy of TLDG for gastric resection under retroflexed endoscopic guidance (GRREG) in patients with gastric cancer in the middle third of the stomach., Methods: Fifteen patients with gastric cancer underwent TLDG using GRREG. Preoperative tumor localization using endoscopic metal clips was performed in all cases. After lymphadenectomy, two-thirds of the estimated transection line was occluded by an endoscopic stapler, beginning at the lesser curvature. Under gastric occlusion, the gastroscope was passed via the narrow lumen along the greater curvature followed by retroflexion to reveal the occlusion line, marking clips, and tumor in the same field of view. This view verified the safe oncological transection line., Results: All patients had cancer-free margins and did not require additional surgery. The mean (±SD) proximal margin was 23.5 ± 10.4 mm. There were no procedure-related complications., Conclusions: GRREG was a safe and effective technique for TLDG. Ideal transection of the stomach was achieved using a combination of an endoscopic stapler and gastroscope retroflexion., (© 2016 S. Karger AG, Basel.)

Pemphigus vulgaris (PV) is an autoimmune blistering disease elicited by anti-desmoglein (DsG) 3 antibody. Although skin lesions tend to be distributed over the entire body, in some patients, they are confined to a restricted area. We report two patients who presented with long-lasting localized PV without detectable anti-DsG antibodies after suffering antibody-positive systemic PV. Initial treatment with prednisolone (PSL) was successful in both patients, but a local relapse occurred on the cheek or lower lip after a reduction in the PSL dose. Biopsy of the localized lesions showed suprabasal acantholysis; no serum DsG antibodies were found. Local immunosuppression therapy was effective in both patients. Based on our findings, we suggest that localized PV without detectable antibodies can develop after systemic PV.

The purpose of this study was to design an endoscopic dissector handle and objectively assess its usability. The handles were designed with increased contact area between the fingers and thumb and the eye rings, and the eye rings were modified to have a more perpendicular insertion angle to the finger midline. Four different handle models were compared, including a conventional product. Subjects performed dissection, exclusion, grasping, precision manipulation and precision handling tasks. Electromyography and subjective evaluations were measured. Compared to conventional handles, the designated handle reduced the muscle load in the extensor and flexor muscles of the forearm and increased subjective stability. The activity of the first dorsal interosseous muscle was sometimes influenced by the shape of the other parts. The ergonomically designed endoscopic dissector handle used in this study achieved high usability. Medical instrument designs based on ergonomic concepts should be assessed with objective indices. Practitioner Summary: The endoscopic dissector handles were designed with increased contact area and more suitable insertion angle between the fingers and thumb and the eye rings. Compared to conventional handles, the designated handle reduced the muscle load in the extensor and flexor muscles of the forearm and increased subjective stability.

Background and Aim: To demonstrate the effect of endoscopic injection sclerotherapy (EIS) with argon plasma coagulation (APC) as a primary/secondary prophylaxis for esophageal varies (EV) on portal hemodynamics and long-term outcomes in cirrhosis., Methods: This prospective study included 48 cirrhotic patients (64.5 ± 11.4 years; 26 bleeders, 22 non-bleeders). Post-treatment outcomes (EIS and APC; median observation period, 12.8 months for recurrence and 21.1 months for prognosis) were evaluated with respect to the findings of hepatic venous catheterization, Doppler ultrasound, and endoscopic ultrasonography (EUS)., Results: All patients showed EV eradication after endoscopic treatment, and a decreased frequency of a patent left gastric vein (pre: 83.3%, post: 27.1%, P < 0.001). However, hepatic venous pressure gradient (HVPG, mmHg) remained unchanged after the treatment, pre: 16.1 ± 3.6, post: 15.6 ± 3.8 (P = 0.269). Cumulative variceal recurrence/rebleeding rates were 25.5%/5.6% and 62.4%/23.1% at 1 and 3 years, respectively. Post-treatment EUS finding, area of submucosal vessels in the cardia ≥12 mm2 was the only significant factor for variceal recurrence (hazard ratio 9.769, 95% confidence interval 3.046-31.337; P < 0.001). Cumulative recurrence rate was significantly higher in patients with area of submucosal vessels in the cardia ≥12 mm2 (58.3% at 1 year and 100% at 3 years) than in those without (11.4% at 1 year and 40.9% at 3 years, P < 0.001). Cumulative overall survival rates were 95.2% and 71.9% at 1 and 3 years, respectively, showing no significant relationship with HVPG., Conclusion: EIS with APC for EV is unlikely to have a significant influence on portal pressure., (© 2015 Japan Gastroenterological Endoscopy Society.)