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Background/Aims: The recommendations on the time interval between pre-cleaning and reprocessing of endoscopes differ in international guidelines, with a low level of evidence. The aim of this study was to investigate the influence of postponing reprocessing on the reprocessing quality after pre-cleaning the flexible endoscopes.Methods: We reprocessed 124 standardized test tubes simulating endoscope channels after soiling and contamination and determined the reprocessing performance. In addition, we examined contaminated gastroscopes, colonoscopes, and bronchoscopes. The duration of interim storage after pre-cleaning was 16 h for 100 test tubes and up to 24 h for 18 endoscopes. We determined the residual protein content and germ load as markers for cleaning and disinfection performance. In addition, we determined biofilm formation by photometry of crystal violet staining.Results: All test tubes and flexible endoscopes showed residual protein content and germ load significantly below legally prescribed threshold values, independent of the interval between pre-cleaning and reprocessing.Conclusions: Our findings indicate that flexible endoscopes could be stored overnight after pre-cleaning without any influence on the quality of reprocessing. While ensuring patient safety, this could simplify logistical processes and enable cost savings.

Background and study aims Despite its widespread adoption, colonoscope still has its limitations. Advancement is often limited by the looping of colon. The isolation of SARS-CoV-2 in stool raises concern for the risk of disease transmission. A single-use robotic colonoscope, the NISInspire-C System, that features a balloon-suction anchorage mechanism was developed to address these. Methods The NISInspire-C balloons are designed to provide anchorage for straightening of the colon during advancement. Angulation at the bending section is tendon-wire driven by servo mechanisms integrated into a robotic control console. This was a pilot, prospective trial to evaluate the safety and feasibility of this system. Healthy volunteers underwent examination with the NISInspire-C, followed by the conventional colonoscope. The procedure time, cecal intubation rates (CIR), complications, and level of pain were measured. Results A total of 19 subjects underwent the examination. The cecal intubation rate was 89.5 % (17/19) and the overall time-to-cecum was 26.3 minutes (SD: 17.9 mins). There were no procedure-related complications. Polyps were detected in seven of 19 (36.8 %) subjects during the NISInspire-C procedure. Three more subjects were found to have adenomatous polyps with the conventional colonoscope. There was minimal variation in level of pain during the procedures with the two colonoscopes. Conclusion The single-use robotic colonoscope NISInspire-C is a safe and feasible alternative to the conventional colonoscope. Further technical refinement is needed to improve the CIR. This study was limited by its small sample size.

Pneumatosis cystoides intestinalis (PCI) is a rare disease characterized by multiple gas-filled cysts in the intestinal wall. The majority of patients with PCI are asymptomatic and have a benign clinical course without treatment. Regular colonoscopic follow-up is not always clinically necessary for PCI; therefore, whether all patients with PCI eventually achieve complete endoscopic resolution remains unclear. We herein present the details of an asymptomatic 58-year-old man diagnosed with PCI in the right colon in 2011 by colonoscopy. We followed him using colonoscopy for 8 years without treatment. The PCI lesions gradually changed into multiple flat yellowish plaque-like lesions, and biopsies revealed that these were elastosis, which is a very rare pathological finding in the colon. To our knowledge, only two reports discuss morphological or histological changes similar to those of PCI. Because the development of yellowish plaque-like lesions histologically representing elastosis associated with PCI is an unrecognized entity, we herein discuss its clinical features, endoscopic findings, and histological findings with a literature review.

Corona viruses are a group of medium-sized positive-sense single-stranded RNA viruses with crown-like structure due to projections noted over the surface of the virus. The infection has been declared as a pandemic by the world health organization (WHO) in March 2020. Health care professionals in endoscopy are at high risk of infection by novel corona virus disease 2019 (COVID-19) from inhalation of droplets, conjunctival contact, feces, and touch contamination. Upper gastrointestinal (GI) endoscopy is considered to be a high-risk aerosol-generating procedures (AGPs) and the live virus has been found in patient stool. Flexible endoscopes when contaminated have been considered as the vector for transmission of infections. Infections related to the side viewing endoscopes and endoscopic ultrasound scopes are more frequent than upper GI scope and colonoscopes. Stratifying patients needing endoscopy and deferral of elective procedures will help to decrease the virus spread. Planning and revision of workflows is necessary for safety of patient and staff and to successfully provide infection prevention and control measures, for this a “three zones and two passages” concept should be followed. Manual cleaning followed by high-level disinfection (HLD), effectively eliminates nearly all microorganisms from endoscopes during reprocessing. Transmission of viral infections during endoscopy is quite rare and, it is usually the result of noncompliance from the essential steps of reprocessing. Reuse of any disposable GI endoscopic device is strongly discouraged. Environmental decontamination is essential to reduce the risk of fomite transmission. Noncritical environmental surfaces frequently touched by hands (e.g., bedside tables and bed rails) and endoscopy furniture and floor should be considered heavily contaminated in patients with intermediate or high risk of COVID-19 and should be thoroughly disinfected at the end of each procedure. If available, negative pressure rooms are preferred for endoscopy, as has been advised by Centers for Disease Control and Prevention (CDC). Staff involved in reprocessing and the cleaning of endoscopy rooms should utilize personal protective equipment (PPE) including N95 mask. Reprocessing staff should undergo necessary training and ongoing annual assessment of competency.

Colonoscopies are considered to be the primary screening test and gold standard test for colorectal cancer. Position changes during colonoscope withdrawal are believed to be associated with an increased adenoma detection rate (ADR) and polyp detection rate (PDR). However, previous results conflicted, and this study aimed to elucidate the effectiveness of dynamic position changes during colonoscope withdrawal. The relevant publications were identified by searching the medical databases. The primary outcomes were the ADR and PDR, which were pooled and analyzed. The secondary outcome was the withdrawal time. The studies that supplied the ADR and PDR for different segments of the colon were separated into subgroup analyses. Five randomized controlled trials were eligible for analysis. The total ADR was higher with dynamic position changes than with a static position (odds ratio, [OR] 1.34; 95% confidence interval [CI] 1.13–1.59; p

OBJECTIVES Some neoplastic lesions remain undetected on colonoscopy. To date, no studies have investigated whether combining cap-assisted colonoscopy with chromoendoscopy increases the adenoma detection rate (ADR). This study aimed to compare cap-assisted chromoendoscopy (CAP/CHROMO) with standard colonoscopy (SC) with respect to their efficacy in detecting adenomas. METHODS This prospective, multicenter, randomized controlled trial included asymptomatic subjects aged 45-75 years who underwent colonoscopy for the first time at 14 university hospitals. Subjects were randomized to either the CAP/CHROMO group (with 0.09% indigo carmine spraying using a cap-mounted catheter at the tip of the colonoscope) or the SC group. All polyps were resected, but only histologically confirmed neoplastic lesions were considered for analysis. The primary outcome was ADR, defined as the proportion of subjects with at least 1 adenoma. RESULTS A total of 1,905 subjects were randomized to the CAP/CHROMO (n = 948) or SC (n = 957) group at 14 centers. Subjects' demographic characteristics were similar between both groups. The CAP/CHROMO group had significantly higher ADR than the SC group (54.4% vs 44.9%, P < 0.001). Significantly, more subjects with at least 1 proximal colon adenoma were identified by CAP/CHROMO (38.6%) than by SC (31.2%) (P = 0.001). The proximal serrated polyp detection rate by CAP/CHROMO was significantly higher in the female subgroup vs SC. However, advanced ADR was not different between the CAP/CHROMO and SC groups (9.3% vs 7.6%, P = 0.180). DISCUSSION CAP/CHROMO markedly improved the ADR and enhanced the detection of proximal adenoma. CAP/CHROMO is feasible for routine application and will allow for a more effective surveillance program.

Colorectal cancer is a major health problem. An improvement to its survival has been demonstrated by performing colonoscopy screenings and removing its precursor lesions: polyps. However, colonoscopy is not infallible and multiple strategies have been proposed aimed at improving the quality thereof. This report describes the endoscopic systems available to improve the detection and characterization of polyps, the different classifications for histological prediction and the current indications of advanced endoscopic diagnostic techniques.

Background and Aims Devices for flattening colon folds can improve polyp detection at colonoscopy. However, there are few data on the endoscopic ring-fitted cap (EndoRings; EndoAid, Caesarea, Israel). We sought to compare adenoma detection with EndoRings with that of standard high-definition colonoscopy. Methods This was a single-center, randomized controlled trial of 562 patients (284 randomized to EndoRings and 278 to standard colonoscopy) at 2 outpatient endoscopy units in the Indiana University Hospital system. Adenoma detection was the primary outcome measured as adenoma detection rate (ADR) and adenomas per colonoscopy (APC). We also compared sessile serrated polyp detection rate, insertion times, withdrawal times, and ease of passage through the sigmoid colon. Results EndoRings was superior to standard colonoscopy in terms of APC (1.46 vs 1.06, P = .025), but there were no statistically significant differences in ADR or sessile serrated polyp detection rate. Mean withdrawal time (in patients with no polyps) was shorter and insertion time (all patients) was longer in the EndoRings arm by 1.8 minutes and 0.75 minutes, respectively. One provider had significantly higher detection with Endo-Rings and contributed substantially to the overall results. Conclusions EndoRings can increase adenoma detection without a significant increase in procedure time, but the effect varies between operators. The use of EndoRings slows colonoscope insertion. (Clinical trial registration number: NCT03418662.)

Rates of incomplete colonoscopy in non-expert settings range up to 13%. Expert colonoscopists can complete ~ 95% colonoscopies when other endoscopists fail; however, a small number remain incomplete even in expert hands, typically due to bowel fixity. Pentax Retroview™ (EC-3490TLi) is a new slim colonoscope with a short turning radius (STR) and greater tip deflection (210°), which allows easy maneuverability across sharply angulated/fixed colonic bends. We evaluated the utility of this colonoscope for completing colonoscopies that fail even in the hands of expert colonoscopists. Retrospective chart review was performed, and main outcomes measured included cecal intubation rate, lesions detected, dosage of sedation used, and complications. Using the STR colonoscope, complete colonoscopy to the cecum was possible in 34/37 patients (91.9%). No loss of lumen/blind advancement was necessary in any of the procedures. No adverse events occurred. Among the completed colonoscopies, 6/34 (17.6%) patients had adenomas, all proximal to the site of prior failure, including one advanced adenoma. All failures (n = 3, 8.1%) had a history of cancer surgeries, with peritoneal carcinomatosis/extensively fixed/frozen bowel (two patients) and an additional diverticular stricture with colo-vesical fistula (one patient). STR colonoscope facilitates completion of a high proportion (91.9%) of colonoscopies that previously failed in expert hands. Its STR allows easy maneuverability across segments of sharp angulation with bowel fixity without need for blind advancement. The use of this colonoscope led to the detection of adenomas in 17.6% of patients, all proximal to the site of prior failed colonoscopy.

Large and complex colon polyps are frequently referred to surgery for fear of perforation that may need emergency surgery. During the last 15 years, advances in clip and suturing devices allowed us to close perforations and avoid surgery. In addition, we have made substantial progress in our understanding of the lesions at risk for either immediate or delayed perforation. This article focuses on the colonoscopic closure of resection defects and perforations and the prevention and treatment of colon perforations after endoscopic resection.

Objective Endoscopic retrograde cholangiopancreatography (ERCP) in patients with Roux-en-Y (RY) reconstruction after total gastrectomy is difficult to be performed with routine instruments. The primary aim of this study was to analyze the feasibility and safety of cap-assisted routine adult colonoscope (CARAC) for ERCP in such patients. Methods We identified 16 consecutive patients with indications of ERCP, who had previously undergone total gastrectomy with RY reconstruction at two tertiary care endoscopy centers. All ERCP procedures were carried out with CARAC. Success rate of achieving the papilla, biliary cannulation and procedure-related adverse events were analyzed. Results The papilla was successful achieved in 11 of 16 (68.8%) cases, and biliary access was subsequently achieved in 8 of 11 (72.7%) cases. Three patients acquired success by percutaneous-endoscopic rendezvous after failed cannulation. The overall clinical success was achieved in 11 of 16 (68.8%) patients. Procedure-related mild acute pancreatitis were found in 4/16 (25%) cases and mild cholangitis in 3/16 (18.8%) cases. There were no serious adverse events such as perforation or bleeding occurred in all patients. Conclusions Cap-assisted routine adult colonoscope for therapeutic ERCP is safe and effective in patients after total gastrectomy with Roux-en-Y reconstruction. This article is protected by copyright. All rights reserved.

Prolongation of cecal intubation time (CIT) directly affects the comfort of the patient and the colonoscopist. In this study, the effectiveness of using an abdominal binder (AB) during colonoscopy on procedure time and colonoscopy outcomes was investigated. We conducted a parallel randomized double-blind sham-device-controlled study of patients who underwent elective outpatient colonoscopy between 1 May 2020, and 31 August 2020. Participants were randomly assigned to AB (n = 173) and sham binder (SB) (n = 173) groups. The primary outcome was CIT. Secondary outcomes were the need for auxiliary maneuvers, the cecum intubation length (CIL) of the colonoscope, visual analog scale (VAS) score, narcotic analgesic dose, and colonoscopy results. Moreover, subgroup analysis was performed in terms of age and obesity indices. A total of 346 patients were enrolled in the study. The mean CIT was similar between groups (AB group 240 secs, control group 250 secs, p > .05). Manual pressure requirement was less in the AB group (27 vs. 36%, p = .069). VAS score and the need for extra narcotic analgesic drugs were prominently lower in the AB group (p p = .016, respectively). In the subgroup analyses, in participants at the age of p = .017, p = .032, respectively). AB use in selected patients may be advantageous during colonoscopy because it reduces the need for analgesics and post-procedure pain, and reduces the need for auxiliary maneuvers in relatively young and obese patients.

Perforation is the most serious adverse event of colonoscopy, but rarely considered from the view of colonoscopists’ second victim experience and perception discordance between colonoscopists and patients. We aimed to evaluate colonoscopists’ second victim experience and the perception discordance between colonoscopists and patients for the colonoscopic perforation. A survey for colonoscopic perforation was performed for the colonoscopists and outpatients who visited the university hospital between February 1, 2020, and April 30, 2020. The questionnaire included questions regarding colonoscopists’ satisfaction for the intervention strategies offered to patients and patient–colonoscopist perception on colonoscopic perforation. A modified Korean version of the “Second Victim Experience and Support Tool (K-SVEST)” was used to assess the second victim experiences and supportive resources for the colonoscopists. Survey results from 160 colonoscopists and 165 patients were analyzed. The colonoscopists’ satisfaction scores were higher for strategies related to sufficient explanation, empathy, courteous listening, and monetary compensation. The scores of the K-SVEST for the second victim experience were highest in psychological distress, followed by loss of professional self-efficacy, colleague support, physical distress, non-work-related support, institutional support, and turnover intentions/absenteeism. Significant patient–colonoscopist discordance was noted for the same colonoscopic perforation scenario on the judgment of medical error, health professionals’ apology, monetary compensation, and criminal penalties for the colonoscopists. Colonoscopists can suffer emotionally and physically from the second victim experience after colonoscopic perforation. In addition, the significant patient–colonoscopist discordance should be considered to make a better communication for the colonoscopic perforation.

Background and AimsHigh quality colonoscopy remains the cornerstone of colon cancer prevention. Studies have shown that generational advances in colonoscopes result in more favorable clinical outcomes. Performance of various endoscopes is determined using objective quality measures. The aim of this study was to compare these measures between two colonoscope platforms.MethodsThis study is a single center retrospective study of 3,761 patients undergoing initial screening colonoscopy between November 2013 and May 2020 using two different colonoscope platforms (Fujifilm EC-760R-V/L, n=2287 and Olympus CF and PCF 180 series, n= 1474). The primary outcomes measured were cecal insertion time, withdrawal time, and adenoma detection rate.ResultsProcedures completed with the Fujifilm colonoscope had mean cecal insertion times that were 2.01 minutes shorter than procedures completed with Olympus (pConclusionsIn this study, Fujifilm colonoscopes outperformed Olympus colonoscopes in screening colonoscopies with statistically and clinically significant shorter cecal insertion times and higher adenoma detection, though both platforms had similar withdrawal times.

Quality assessment of the colon consists of detailed, systematic and meticulous inspection of the entire colonic mucosa. A thorough and careful mucosal inspection is essential to prevent colorectal cancer (CRC) and cancer-related mortality.1 The detection and resection of precancerous polyps is the primary goal of screening colonoscopy. Recently, there has been a focus on quality and safety of colonoscopy. Worldwide, the demand for colonoscopy is increasing, and with a limited workforce, efficient working is of paramount importance.2 ### Quest for a colonoscopy efficiency marker We performed an extensive search in the literature for the definition of colonoscopic efficiency (CE); however, no clear definition was found. We propose the following working definition as ‘the ability to detect clinically significant pathologies within acceptable time limits without compromising the quality or safety of the examination’. CE is augmented by the following factors: optimal bowel preparation, technical ease of the procedure, technique of the endoscopist, high-definition and high-quality video imaging, and uninterrupted panoramic view of mucosal surface. Although mucosal views may be improved with dynamic position changes and routine retroflexion in the rectum, these manoeuvres may not be effective in narrower colonic segments and flexures.3 Recent technological developments in the field of colonoscopy such as wide-angle view colonoscopes and disposable distal attachments (Endocuff Vision, transparent cap and Endorings) helped to improve the lateral and backward view of the mucosal folds.4–9 These advancements demonstrated an improvement in the quality and performance of the procedure. However, none of the studies explored the impact on CE of the technologies. We aimed to assess the performance of a new marker of colonoscopic efficiency. We propose SP6 (number of significant polyps detected per 6 min withdrawal time during colonoscopy) as …

Conventional lesion-up colorectal ESD has the potential risk of iatrogenic perforation due to the knife’s direction toward the muscular layer of the bowel wall. If we rotate the endoscope to the proper position, the mucosal flap is easy to be lifted down by tip attachment and the knife is easy to approach the proper dissection plane, which may prevent the perforation and facilitate difficult ESD. We aimed to retrospectively assess the safety and efficacy of this rotating technique compared with the conventional lesion-up dissection regardless of shape, location, or size of the tumor, and investigated in short- and long-term outcomes following the ESD procedure. 41 lesions were enrolled into rotating technique group and 37 lesions in lesion-up group. The dissection speed was significantly faster in the rotating technique group (p = 0.023). R0 resection rate was significantly higher in rotating technique group (p = 0.008). The rate of perioperative complication was significantly higher in lesion-up method group (p = 0.003). Local recurrence was higher in lesion-up group (p = 0.001). Recurrence-free rate was higher in rotating technique group (p = 0.018). The endoscope rotating is a useful technique for difficult colorectal ESD due to easy approaching the proper dissection plane. This technique also increases the rate of en bloc resections, R0 resections regardless of size, shape, and location and improves dissection speed without increasing the incidence of adverse events.

The latest state of the art technological innovations have led to a palpable progression in endoscopic imaging and may facilitate standardisation of practice. One of the most rapidly evolving modalities is artificial intelligence with recent studies providing real-time diagnoses and encouraging results in the first randomised trials to conventional endoscopic imaging. Advances in functional hypoxia imaging offer novel opportunities to be used to detect neoplasia and the assessment of colitis. Three-dimensional volumetric imaging provides spatial information and has shown promise in the increased detection of small polyps. Studies to date of self-propelling colonoscopes demonstrate an increased caecal intubation rate and possibly offer patients a more comfortable procedure. Further development in robotic technology has introduced ex vivo automated locomotor upper gastrointestinal and small bowel capsule devices. Eye-tracking has the potential to revolutionise endoscopic training through the identification of differences in experts and non-expert endoscopist as trainable parameters. In this review, we discuss the latest innovations of all these technologies and provide perspective into the exciting future of diagnostic luminal endoscopy.

Multiple studies have documented a high rate of contaminated colonoscopes after reprocessing. Contaminated reusable colonoscopes may increase the risk of device-related patient infections. As disposable colonoscopes enter the market, they may play a role in infection prevention and may be cost-effective at some facilities or in high-risk patients. Using a micro-costing approach, this study found that the cost per colonoscopy including purchase, maintenance and reprocessing ranges from US$188.64 at high volume centres (3000 annual procedures) to US$501.16 at low volume centres (1000 annual procedures). Accordingly, per-procedure capital costs range from US$87.48 to US$262.45; repair costs range from US$68.77 to US$206.32; cleaning supplies and labour costs US$32.39 and infections requiring hospitalisation cost US$20.12 to US$46.52. As disposable colonoscopes enter the market, low volume centres are most likely to achieve cost savings. Determining if post-procedural infection rates differ with reusable vs disposable colonoscopes is needed. ### In more detail Each year more than 15 million colonoscopy procedures are performed in the USA and the number is increasing.1 Colonoscopy is generally thought to be safe; however, patients are sometimes hospitalised afterwards, due to infections that may have been transmitted via contaminated colonoscopes (MAUDE Adverse Event Report).2 3 Colonoscopy-related infections and complications have been reported in multiple studies, although at lower rates compared with endoscopic retrograde cholangiopancreatography (ERCP).1 4 5 Guideline revisions in response to endoscope-associated infections require healthcare institutions to invest more resources in the high-level disinfection process or conversion to sterilisation (Ofstead et al ).5,6 Despite colonoscopy being the highest volume GI procedure, the true cost and time associated with reusable colonoscopes are unknown. The purpose of this study was to explore real-world costs associated with …

Cecal intubation is a critical aspect of effective, complete colonoscopy. Difficult colonoscopy is most often considered as one in which it is challenging or impossible to reach the cecum. It may be a common occurrence due to patient and/or endoscopist factors. Incomplete colonoscopies should be avoided, since patients in this context present an important prevalence of lesions that escape examination. The approach to successful cecal intubation should depend on characterization of the problem as redundant colon or difficult sigmoid colon. Most patients with a prior incomplete colonoscopy can be colonoscoped successfully, if careful attention is paid to technique, using a variety of scopes, colonoscopy methods and additional equipment. Sufficient time should be allotted to make the attempt.

Missed adenomas are likely to be located in the proximal colon and failure to detect these lesions might explain the occurrence of a certain percentage of interval carcinomas. Though studies have demonstrated increased detection of significant neoplastic lesions in colonoscopic examinations where the withdrawal time is 6 min or more, there are no recommendations on how much time to spend in each colonic segment. The aim of the trial was to find ways to reduce the number of lesions missed in the proximal segments of the colon assessing the difference in adenoma detection rate (ADR) between two colonoscopic withdrawal timed techniques. This was a randomized trial in a university hospital. Population was composed of patients referred for screening colonoscopy. The Main Outcome measurements was ADRs for patients subjected to a timed colonoscopy with specific withdrawal times, with special interest in the proximal colon, and implying a minimum of 2-min withdrawal delay in the cecum and right colon, a 1-min delay time in the transverse colon, and a minimum additional 3-min delay time in the left colon, as compared to a standard timed colonoscopy with free withdrawal delay time of at least 6 min. A total of 1160 patients were included. Eleven were initially excluded due to incomplete colonoscopies. Of the remaining 1149 patients, 573 were randomized to the group with fixed withdrawal times (Group A) and 576 to conventional withdrawal (Group B). Median age was 57 years (SD 6), a total of 634 (55.2%) were male patients and the mean withdrawal time was 7:05 min (SD 1 min). Seven hundred and eighty-one adenomas/serrated lesions were found in 470 patients (1.66 per patient), with 28 advanced lesions and 3 adenocarcinomas. Global ADR was 41% with no significant statistical differences between the two groups (42.1% vs 39.8%, p 0.43), respectively. A multivariate analysis showed clear relation between the finding of adenomas and higher BBPS ratings (Adjusted Odds Ratio [aOR] 0.92, p 0.05), age (aOR 1.03, p 0.01), male sex (aOR 1.51, p 0.001), and time of withdrawal (aOR 1.17, p 0.001), while no association was observed with either withdrawal technique (aOR 0.89, IC 95% 0.70–1.03, p 0.32). There was no statistical significant difference between the two groups concerning the finding of proximal lesions (cOR 0.93, CI 95% 0.71–1.20, p 0.56) (aOR 0.89, CI 95% 0.69–1.17, p 0.41) or serrated polyps (cOR 0.81, CI 95% 0.51–1.27, p 0.35) (aOR 0.81, IC 95% 0.51–1.28, p 0.36). Fixed withdrawal times did not prove to lead to an increase in the number of detected adenomas. Nevertheless, our study supports previous reports stating that longer withdrawal times are indeed associated with better proximal and distal adenoma detection.

Colonoscopy has been established as the gold standard for the detection of colorectal neoplasms. Adenoma detection rate (ADR) is one of the most important quality indicator of colonoscopy, and, as it has been recommended by a European Society of Gastrointestinal Endoscopy (ESGE), the benchmark for ADR is 20%. However, ADR widely varies, and almost one fourth of polyps and adenomas are missed. Currently several techniques have been developed with the aim to improve the quality of colonoscopy. Among them there are image-enhanced endoscopy (IEE) and techniques or devices that improve mucosal observation. IEE includes chromoendoscopy and virtual chromoendoscopy (NBI, FICE, AFI, i-scan); among techniques which enable better observation of the mucosa there are add-on devices, such as transparent cap, Endocuff, Endocuff Vision, Endorings; and wide-angle colonoscopes (full spectrum endocopy - FUSE). In the literature review, these mentioned techniques and their effect on ADR are described.

ObjectiveEsophagogastroduodenoscopy (EGD) is the pivotal procedure in the diagnosis of upper gastrointestinal lesions. However, there are significant variations in EGD performance among endoscopists, impairing the discovery rate of gastric cancers and precursor lesions. The aim of this study was to construct a real-time quality improving system, WISENSE, to monitor blind spots, time the procedure and automatically generate photodocumentation during EGD and thus raise the quality of everyday endoscopy.DesignWISENSE system was developed using the methods of deep convolutional neural networks and deep reinforcement learning. Patients referred because of health examination, symptoms, surveillance were recruited from Renmin hospital of Wuhan University. Enrolled patients were randomly assigned to groups that underwent EGD with or without the assistance of WISENSE. The primary end point was to ascertain if there was a difference in the rate of blind spots between WISENSE-assisted group and the control group.ResultsWISENSE monitored blind spots with an accuracy of 90.40% in real EGD videos. A total of 324 patients were recruited and randomised. 153 and 150 patients were analysed in the WISENSE and control group, respectively. Blind spot rate was lower in WISENSE group compared with the control (5.86% vs 22.46%, pConclusionsWISENSE significantly reduced blind spot rate of EGD procedure and could be used to improve the quality of everyday endoscopy.Trial registration numberChiCTR1800014809; Results.

Contains fulltext : 205162.pdf (Publisher’s version ) (Open Access) BACKGROUND AND AIMS: Colorectal cancer (CRC) is largely preventable with routine screening and surveillance colonoscopy; however, interval cancers arising from precancerous lesions missed by standard colonoscopy still occur. An increased adenoma detection rate (ADR) has been found to be inversely associated with interval cancers. The G-EYE device includes a reusable balloon integrated at the distal tip of a standard colonoscope, which flattens haustral folds, centralizes the colonoscope's optics, and reduces bowel slippage. The insufflated balloon also aims to enhance visualization of the colon during withdrawal, thereby increasing the ADR. METHODS: In this randomized, controlled, international, multicenter study (11 centers), patients (aged >/=50 years) referred to colonoscopy for screening, surveillance, or changes in bowel habits were randomized to undergo either balloon-assisted colonoscopy by using an insufflated balloon during withdrawal or standard high-definition colonoscopy. The primary endpoint was the ADR. RESULTS: One thousand patients were enrolled between May 2014 and September 2016 to undergo colonoscopy by experienced endoscopists; 803 were finally analyzed (standard colonoscopy n = 396; balloon-assisted colonoscopy n = 407). Baseline parameters were similar in both groups. Balloon-assisted colonoscopy provided a 48.0% ADR compared with 37.5% in the standard colonoscopy group (28% increase; P = .0027). Additionally, balloon-assisted colonoscopy provided for a significant increase in detection of advanced (P = .0033) flat adenomas (P < .0001) and sessile serrated adenomas/polyps (P = .0026). CONCLUSION: Balloon-assisted colonoscopy yielded a higher ADR and increased the detection of advanced, flat, and sessile serrated adenomas/polyps when compared with standard colonoscopy. Improved detection by the G-EYE device could impact the quality of CRC screening by reducing miss rates and consequently reducing interval cancer incidence. (Clinical trial registration number: NCT01917513.).

BACKGROUND AND AIMS: Studies from our group and others demonstrate residual fluid in 42% to 95% of endoscope working channels despite high-level disinfection and drying. Additionally, persistent simethicone has been reported in endoscope channels despite reprocessing. METHODS: Endoscopy was performed by using water or varied simethicone concentrations (0.5%, 1%, 3%) for flushing. After high-level disinfection/drying, we inspected endoscope working channels for retained fluid by using the SteriCam borescope. Working channel rinsates were evaluated for adenosine triphosphate (ATP) bioluminescence. Fourier transform infrared spectroscopy was performed on fluid droplets gathered from a colonoscope in which low-concentration simethicone was used. RESULTS: Use of medium/high concentrations of simethicone resulted in a higher mean number of fluid droplets (13.5/17.3 droplets, respectively) and ATP bioluminescence values (20.6/23 relative light units [RLUs], respectively) compared with that of procedures using only water (6.3 droplets/10.9 RLUs; P < .001). Two automated endoscope reprocessing cycles resulted in return of a fluid droplet and ATP bioluminescence values to ranges similar to that of procedures that used only water (P = .56). Low-concentration simethicone did not increase the mean residual fluid or ATP bioluminescence values compared with procedures that used only water (5.8 droplets/15.6 RLUs). Fourier transform infrared analysis revealed simethicone in the endoscope working channel after use of low-concentration simethicone. CONCLUSIONS: Use of medium/high concentrations of simethicone is associated with retention of increased fluid droplets and higher ATP bioluminescence values in endoscope working channels, compared with endoscopes in which water or low concentration simethicone was used. However, simethicone is detectable in endoscopes despite reprocessing, even when it is utilized in low concentrations. Our data suggest that when simethicone is used, it should be used in the lowest concentration possible. Facilities may consider 2 automated endoscope reprocessor cycles for reprocessing of endoscopes when simethicone has been used. (Gastrointest Endosc 2019;89:115–23.)

Background/Aim: A prospective randomized open label parallel trial, comparing the quality of life (QoL) after endoscopic placement of a self-expandable metal stent or primary tumor resection, in patients with stage IV colorectal cancer was performed. Patients and Methods: Thirty-three patients affected with stage IV colorectal cancer and unresectable metastases were randomly assigned into two groups: Group 1 (16 patients), that underwent self-expandable metal stent positioning and Group 2 (17 patients), in which primary tumor resection was performed. Karnofsky performance scale and QoL assessment using the EQ-5D-5L™ questionnaire was administered before treatment and thereafter at 1, 3 and 6 months. Results: At 1 month, index values showed a statistically significant deterioration of the QoL in patients of Group 2 when compared to those of Group 1 (p=0.001; 95%CI=0.065-0.211) whereas, at 6 months, index values showed a statistically significant deterioration of the QoL in patients of Group 1 (p

Current research suggests that for certain types of gastrointestinal endoscopes, longer shelf life (the interval of storage after which endoscopes should be reprocessed before their reuse) may not increase the likelihood of endoscope contamination. Scope contamination may, in fact, be related primarily to either inadequate disinfection processes or inadvertent contamination during storage, not to duration of storage. The purpose of this study evaluated the presence of bacteria and fungus following liquid chemical sterilization in colonoscopes and gastroscopes, after 12 weeks of shelf life during which time personal protective equipment was used during endoscope storage cabinet access. We stored four colonoscopes and two gastroscopes in a cabinet for 12 weeks after liquid chemical sterilization and the cabinet was only accessed during the 12-week period wearing personal protective equipment (gown and gloves). Scopes were tested for bacteria and fungus at the end of 12 weeks. No bacteria or fungus grew on any of the scopes. This study provides further support that contaminated endoscopes may be related to either inadequate disinfection or contamination during storage, not shelf life.

Colonoscopy reduces the risk of colorectal cancer, by interrupting the adenoma-carcinoma sequence enabling the detection and removal of adenomas before they turn into colorectal cancer. Colonoscopy has its limitations as adenoma miss rates as high as 25% have been reported. The reasons for missed pathology are complicated and multi-factorial. The recent drive to improve adenoma detection rates has led to a plethora of new technologies. Areas covered: An increasing number of advanced endoscopes and distal attachment devices have appeared in the market. Advanced endoscopes aim to improve mucosal visualization by widening the field of view. Distal attachment devices aim to increase adenoma detection behind folds by flattening folds on withdrawal. In this review article, we discuss the three following distal attachment devices: the transparent cap, the Endocuff, and the Endoring. Expert commentary: The authors believe that the distal attachment devices will have a greater benefit for endoscopists with low baseline adenoma detection rates.

INTRODUCTION A variety of add-on devices and new-generation endoscopes have the potential to detect lesions 'hidden' behind colonic folds. We measured the effect of these new modalities on colonoscopy's lesions miss rates by a meta-analysis of data from individual studies. MATERIALS AND METHODS We performed literature searches in Medline and Cochrane Library for back-to-back randomized-controlled trials evaluating colonoscope add-on devices and new endoscopes in terms of lesions miss rates. The effect size on study outcomes is shown as relative risk (95% confidence interval). RESULTS We identified nine tandem studies with 1594 patients: seven evaluating add-on devices (one with cap, two with Endocuff, one with Endorings, one with Third-Eye Retroscope, two with G-EYE endoscope) and two evaluating the full-spectrum endoscopy system (FUSE) in comparison with conventional colonoscopy (CC). Overall, adenoma miss rate (AMR) was significantly lower with add-on devices/FUSE [0.33 (0.22-0.50), P

Endoscopic procedures are vital to gastrointestinal disease diagnosis and management, but risk infection transmission. In Australia, endoscopes undergo monthly-to-quarterly microbiological testing, to prevent patient infection. Endoscopes are used more frequently, meaning contamination may not be detected by this surveillance before infection transmission occurs.To evaluate the use of adenosine triphosphate (ATP) measurement, alongside standard microbiological cultures, in detecting endoscope contamination before high-level disinfection. Using these results, we also aimed to confirm the efficacy of manual cleaning in reducing levels of ATP and cfu/mL.Seventeen in-clinical-use gastroscopes and 24 in-clinical-use colonoscopes from the Liverpool Hospital Endoscopy unit were sampled across three separate cleaning stages before high-level disinfection. Colony counts and ATP measurements were then performed on these samples.The correlation between the cfu/mL and RLU of samples collected from colonoscopes was 0.497 (95% confidence interval: 0.28-0.66; P 0.0001). The correlation between cfu/mL and RLU for samples collected from gastroscopes was 0.377 (0.08-0.61; P = 0.0138). RLU and cfu/mL values were shown to fall significantly (P 0.005) following precleaning and manual cleaning.There was a significant correlation between ATP and cfu/mL measured from samples collected before high-level disinfection. Precleaning and manual cleaning were shown to reduce ATP and microbiological load significantly. ATP measurement can be performed within minutes with little training and produces results that are easy to interpret. These findings warrant further research on the utility of ATP measurement as a screening tool for detecting endoscope contamination after high-level disinfection.

The endoscopic lens becomes clouded and its visibility reduces during colorectal endoscopic submucosal dissection (ESD), especially in cases with submucosal fatty tissue. Dual red imaging (DRI) is a novel image-enhanced endoscopic technique that improves endoscopic visibility. This study aimed to evaluate the predictive factors of submucosal fatty tissue and the clinical usefulness of DRI in maintaining clear visibility during colorectal ESD. The study participants included 586 consecutive patients with 645 colorectal tumors who underwent ESD between January 2014 and July 2017. First, the degree of submucosal fatty tissue was evaluated by reviewing recorded images, and the clinical characteristics of the patients and tumors related to severe submucosal fatty tissue were evaluated. Second, 34 tumors resected using DRI were propensity score-matched in a 1:1 ratio to other resected tumors using white light imaging (WLI), and the degree of endoscope lens cloudiness and clinical outcomes were evaluated. The proportion of tumors located in the right side of the colon, body mass index (≥ 25, BMI), and hemoglobin A1c (≥ 6.5%, HbA1c) were significantly higher in patients with severe submucosal fatty tissue. The visibility in the DRI group was significantly better than in the WLI group. Treatment outcomes in the DRI group were as good as those in the WLI group. Tumor location in the right side of the colon, BMI (≥ 25), and HbA1c (≥ 6.5%) are the predictive factors of severe submucosal fatty tissue. DRI is useful in maintaining clear visibility during colorectal ESD, especially with submucosal fatty tissue.

Although colonoscopy has been proven effective in reducing the incidence of colorectal cancer through the detection and removal of precancerous lesions, it remains an imperfect examination, as it can fail in detecting up to almost one fourth of existing adenomas. Among reasons accounting for such failures, is the inability to meticulously visualize the colonic mucosa located either proximal to haustral folds or anatomic curves, including the hepatic and splenic flexures. In order to overcome these limitations, various colonoscope attachments aiming to improve mucosal visualization have been developed. All of them - transparent cap, Endocuff, Endocuff Vision and Endorings - are simply mounted onto the distal tip of the scope. In this review article, we introduce the rationale of their development, present their mode of action and discuss in detail the effect of their implementation in the detection of lesions during colonoscopy.

Endoscopes are medical instruments that are used routinely in health structures. Due to their invasive nature and contact with many patients, they may cause hospital-acquired infections if not disinfected correctly. To ensure a high-level disinfection procedure or reprocessing, since the methods currently adopted in our institute are adequate, we evaluated retrospectively the presence of microorganisms in our endoscopes after reprocessing. Microbiological surveillance was performed from January 2016 to December 2019 in the instruments in use in our endoscopic room after reprocessing. In total, 35 endoscopes (3 duodenoscopes, 3 echoendoscopes, 12 bronchoscopes, 5 colonoscopes, and 12 gastroscopes) were evaluated for the presence of microorganisms, including multidrug-resistant pathogens and indicator microorganisms (IMOs). Our procedures were in agreement with an internal protocol based on Italian, international, and the Center for Disease Control and Prevention (CDC) recommendations. Of a total of 811 samples, 799 (98.5%) complied with the regulatory guidelines, while 9 (1.1%) were positive for IMOs, and 3 (0.4%) displayed more than 10 colony-forming units (CFU) of environmental and commensal pathogens. Our results show that the internal reprocessing protocol is very efficient, leading to a very low number of observed contaminations, and it could be easily implemented by other health facilities that face a huge number of hospital-acquired infections due to incorrectly disinfected endoscopes.

We developed a magnetic-assisted capsule colonoscope system with integration of computer vision-based object detection and an alignment control scheme. Two convolutional neural network models A and B for lumen identification were trained on an endoscopic dataset of 9080 images. In the lumen alignment experiment, models C and D used a simulated dataset of 8414 images. The models were evaluated using validation indexes for recall (R), precision (P), mean average precision (mAP), and F1 score. Predictive performance was evaluated with the area under the P-R curve. Adjustments of pitch and yaw angles and alignment control time were analyzed in the alignment experiment. Model D had the best predictive performance. Its R, P, mAP, and F1 score were 0.964, 0.961, 0.961, and 0.963, respectively, when the area of overlap/area of union was at 0.3. In the lumen alignment experiment, the mean degrees of adjustment for yaw and pitch in 160 trials were 21.70° and 13.78°, respectively. Mean alignment control time was 0.902 s. Finally, we compared the cecal intubation time between semi-automated and manual navigation in 20 trials. The average cecal intubation time of manual navigation and semi-automated navigation were 9 min 28.41 s and 7 min 23.61 s, respectively. The automatic lumen detection model, which was trained using a deep learning algorithm, demonstrated high performance in each validation index.

Based on the high prevalence of endometriosis (EM) and the good chance of its deep infiltration, EM is frequently involving the colorectum and found during colonoscopy by accident. However, there are not always classical signs present on the surface of bowel mucosa due to its serosal origin. EM is hardly diagnosed and missed at colonoscopy.

Significance: Colorectal cancer incidence has decreased largely due to detection and removal of polyps. Computer-aided diagnosis development may improve on polyp detection and discrimination. Aim: To advance detection and discrimination using currently available commercial colonoscopy systems, we developed a deep neural network (DNN) separating the color channels from images acquired under narrow-band imaging (NBI) and white-light endoscopy (WLE). Approach: Images of normal colon mucosa and polyps from colonoscopies were studied. Each color image was extracted based on the color channel: red/green/blue. A multilayer DNN was trained using one-channel, two-channel, and full-color images. The trained DNN was then tested for performance in detection of polyps. Results: The DNN performed better using full-colored NBI over WLE images in the detection of polyps. Furthermore, the DNN performed better using the two-channel red + green images when compared to full-color WLE images. Conclusions: The separation of color channels from full-color NBI and WLE images taken from commercially available colonoscopes may improve the ability of the DNN to detect and discriminate polyps. Further studies are needed to better determine the color channels and combination of channels to include and exclude in DNN development for clinical use.

Purpose: The purpose of this study was to evaluate the disinfection efficacy of peracetic acid disinfectant (Type III) on gastrointestinal endoscopy. Methods: Endoscopes were disinfected, respectively, by 2% glutaraldehyde and peracetic acid disinfectant (Type III) according to the procedures stipulated by the 2016 version of “Regulation for cleaning and disinfection technique of flexible endoscope,” then samples were collected through biopsy channel at the specified steps. The bacterial count and pathogenic bacteria of these samples were detected, and hepatitis B virus surface antigen, hepatitis C virus antibody, and Treponemiapallidum antibody were detected by chemiluminescent microparticle immunoassay in peracetic acid disinfectant (Type III) group. The samples from the peracetic acid disinfectant (Type III) group were collected for 5 days continuously. Results: In total, 56 gastroscopes and 16 colonoscopes were disinfected by 2% glutaraldehyde (GA Group), 46 gastroscopes, and 15 colonoscopes were disinfected by peracetic acid disinfectant (Type Ⅲ) (PAA Group). After disinfection, the bacterial count was significantly reduced in the 2 groups (P0.05; total qualified rate: 98.36% (60/61) vs. 94.44% (68/72), P>0.05], the qualified rate of colonoscopes in the 2 groups were both 100.00% (15/15, 16/16). After disinfecting by peracetic acid disinfectant (Type Ⅲ), hepatitis B virus surface antigen, anti-hepatitis C virus, and Treponemiapallidum antibody were negative. In term of colonies number detected for 5 days continuously, there was no significant difference at different collection steps (P>0.05). Conclusions: Peracetic acid disinfectant (Type III) can be well applied to clinical with meeting the standard of high-level disinfection for gastrointestinal endoscopy, and after disinfecting by peracetic acid disinfectant (Type III), there was no obvious bacterial residue in the biopsy channel.

Background A high-quality screening colonoscopy is critical in the prevention and early detection of colorectal cancer. Hence, several innovations and techniques have been proposed to potentially improve the quality of colonoscopy. One of which is the use of new generation high definition colonoscopes to increase the adenoma detection rate (ADR). This study aims to determine the difference of ADR between the new generation high definition colonoscopes. Methods This is a single-centre, retrospective cross-sectional study that compares the ADR with screening colonoscopies using 180/190 series Olympus colonoscopes and 290 series Olympus colonoscopes. A review of endoscopy databank over a 6 month period (January 2019 to June 2019) was done. Asymptomatic patients, age 50 – 75 years, classified as average risk for developing colon cancer, who had their indexed colonoscopy performed by experienced endoscopist were included. Results A total of 197 out of 340 patients reviewed met the inclusion criteria. 64% of colonoscopies were performed using the 290 series Olympus colonoscopes. The majority of included patients are male, 77% of patients in the 180/190 series group and 53% of patients in the 290 series group. The ADR using the 180/190 series Olympus colonoscope group is 25% (95% CI of 17%-37%) as compared to 45% (95% CI of 27%-54%) using the 290 series Olympus colonoscopes. The difference is statistically significant with a p-value of 0.006. Conclusions The 290 series Olympus colonoscopes showed a statistically significant higher adenoma detection rate as compared to the 180/190 series Olympus colonoscopes. This reflects a significant difference between the new generation high definition colonoscopes in terms of ADR.

Adoption of artificial intelligence (AI) in clinical medicine is revolutionizing daily practice. In the field of colonoscopy, major endoscopy manufacturers have already launched their own AI products on the market with regulatory approval in Europe and Asia. This commercialization is strongly supported by positive evidence that has been recently established through rigorously designed prospective trials and randomized controlled trials. According to some of the trials, AI tools possibly increase the adenoma detection rate by roughly 50% and contribute to a 7-20% reduction of colonoscopy-related costs. Given that reliable evidence is emerging, together with active commercialization, this seems to be a good time for us to review and discuss the current status of AI in colonoscopy from a clinical perspective. In this review, we introduce the advantages and possible drawbacks of AI tools and explore their future potential including the possibility of obtaining reimbursement.

Summary Background At present, the most frequent method for processing flexible gastrointestinal (GI) endoscopes is cleaning followed by high-level disinfection as terminal sterilization is often not practicable. Post-processing monitoring studies consistently show high levels of positive cultures remaining on endoscopes, which can lead to patient infection and even fatality. The processing deficiency is attributed to the complex design of endoscopes, incomplete cleaning, formation of biofilms and lack of margin of safety with high-level disinfection. Objective To demonstrate that flexible GI endoscopes can be practicably terminally sterilized. Methods An endoscope sterilization cycle was developed in a vaporized hydrogen peroxide sterilization system. The cycle was used to study the sterilization of flexible GI endoscopes which included colonoscopes and duodenoscope and material compatibility for both original flexible GI endoscopes and those experimentally modified endoscopes using compatible materials. Results Testing demonstrated that the vaporized hydrogen peroxide can sterilize flexible GI endoscopes (colonoscopes, duodenoscope) with a sterility assurance level of 10−6. Additionally, no recoverable survivors were detected when devices were artificially soiled with hard water and serum. Material compatibility test results demonstrated that replacing molybdenum disulphide lubricant with a graphite-based inert lubricant can make them compatible with vaporized hydrogen peroxide sterilizers. Conclusion Flexible GI endoscopes can be practicably terminally sterilized using vaporized hydrogen peroxide sterilization technologies if their materials are revised to become compatible.

Microbiological surveillance carried out in order to verify the effectiveness of endoscope reprocessing does not include the research of viruses, although endoscopes may be associated with the transmission of viral infections. This paper reports the experience of the University Hospital of Pisa in managing the risk from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during an endoscopy. A review of the reprocessing procedure was conducted to assess whether improvement actions were needed. To verify the reprocessing efficacy, a virological analysis was conducted both before and after the procedure. Five bronchoscopes and 11 digestive endoscopes (6 gastroscopes and 5 colonoscopes) were sampled. The liquid samples were subjected to concentration through the use of the Macrosep Advance Centrifugal Devices (PALL Life Sciences, Port Washington, NY, USA) and subsequently analyzed using the cobas&reg, SARS-CoV-2 Test (Roche Diagnostics, Basel, Switzerland), together with eSwab 490 CE COPAN swabs (COPAN, Brescia, Italy), which were used to sample surfaces. In accordance with the first ordinance regarding the coronavirus disease 2019 (COVID-19) emergency issued by the Tuscany Region in March 2020, a procedure dedicated to the management of the COVID-19 emergency in endoscopic practices was prepared, including the reprocessing of endoscopes. The virological analysis carried out on samples collected from endoscopes after reprocessing gave negative results, as well as on samples collected on the endoscopy column surfaces and the two washer-disinfectors that were dedicated to COVID-19 patients. The improvement in endoscope reprocessing implemented during the COVID-19 emergency was effective in ensuring the absence of SARS-CoV-2, thus reducing the risk of infections after an endoscopy on COVID-19 patients.

Background and Aims: Several add-on devices have been developed to increase rates of colon adenoma detection. We aimed to compare the endocuff-assisted colonoscopy with cap-assisted colonoscopy through a pairwise meta-analysis of randomized trials. Methods: We searched the PubMed/Medline and Embase database through March 2020 and identified 6 randomized controlled trials (comprising 2,027 patients). The primary outcome was adenoma detection rate; secondary outcomes included sessile serrated adenoma detection rate, mean adenoma per colonoscopy, cecal intubation rate and time to reach cecum. Safety data were also analyzed. We performed pairwise meta-analysis through a random effects model and expressed data as risk ratio and 95% confidence interval. Results: Overall, pooled adenoma detection rate was 48.1% (39.3-56.8%) with endocuff and 40.5% (30.4- 50.6%; risk ratio 1.14, 0.96-1.35) with cap. Proximal adenoma detection rate was 45.7% (36.8-54.7%) and 24% (17-45.1%) with endocuff and cap, respectively (risk ratio 2.04, 0.93-4.49), whereas endocuff outperformed cap-assisted colonoscopy in detecting diminutive (≤ 5 mm) adenomas (risk ratio 2.74, 1.53-4.90) and in terms of mean adenoma per colonoscopy (mean difference 0.31, 0.05 -0.57; p=0.02). Sessile serrated adenoma detection rate (risk ratio 1.36, 0.72-2.59), cecal intubation rate (risk ratio 0.99, 0.98-1.00), and time to reach cecum (6.87 min versus 6.87 min) were similar between the two groups. No serious adverse event was observed. Conclusion: Endocuff-assisted colonoscopy seems to provide a higher adenoma detection rate as compared to cap-assisted colonoscopy, in particular concerning smaller diminutive polyps.

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