Utility of a Passive Bending Colonoscope for Endoscopic Retrograde Cholangiopancreatography in Patients with Surgically Altered Anatomy

BACKGROUND AND AIM

The utility of a passive bending colonoscope (PBCS) in ERCP for patients with surgically altered anatomy has not been established. This study compared the outcome of PBCS-ERCP and balloon-assisted enteroscope (BAE)-ERCP.

METHODS

This multicenter observational study included 343 patients with surgically altered anatomy who underwent ERCP. Among these, 110 underwent PBCS-ERCP and 233 underwent BAE-ERCP. Propensity score matching was applied, and a final cohort of 210 (105 in each group) with well-balanced backgrounds was analyzed. The primary outcome was the success rate of reaching anastomosis or ampulla of Vater. Secondary endpoints included the cannulation success rate, completion rate, procedure time (to reach, cannulate, complete), and adverse events.

RESULTS

The success rate for reaching the target was 91.4% (96/105) with PBCS and 90.5% (95/105) with BAE (odds ratio [95% CI] 1.12, [0.44-2.89], P = 0.809). The mean time required to reach the target was significantly shorter in PBCS: 10.04 min (SD, 9.62) with PBCS versus 18.77 min (SD, 13.21) with BAE (P < 0.001). There were no differences in the success of cannulation or procedure completion, although the required times for cannulation and procedure completion were significantly shorter in PBCS. The incidence of adverse events was significantly higher in BAE (19.0%) than in PBCS (4.8%; P < 0.001).

CONCLUSIONS

In patients with surgically altered anatomy, PBCS-ERCP showed promising results with shorter time to reach, cannulate, and a lower incidence of adverse events compared with BAE-ERCP. The success rate of reaching was favorable through PBCS compared with BAE.

CLINICAL TRIAL REGISTRATION

UMIN000045546.

Towards Semi-Autonomous Colon Screening Using an Electromagnetically Actuated Soft-Tethered Colonoscope Based on Visual Servo Control

OBJECTIVE

Conventional colonoscopy using a flexible colonoscope remains two major limitations, including patient discomfort and difficult manipulations for surgeons. Robotic colonoscopes have been developed to conduct colonoscopy in a patient-friendly manner. However, most robotic colonoscopes still maintain nonintuitive and difficult manipulations, which limits their clinical applications. In this paper, we demonstrated visual servo-based semi-autonomous manipulations of an electromagnetic actuated soft-tethered (EAST) colonoscope, which aims to lower difficulties of robotic colonoscope manipulations.

METHODS

Kinematic modeling of EAST colonoscope is conducted, with an adaptive visual servo controller established. Template matching method and a lumen and polyp detection model are developed to enable semi-autonomous manipulations, including region-of-interest automatic tracking and autonomous navigation with automatic polyp detection.

RESULTS

The EAST colonoscope demonstrates visual servoing with an average convergence time of around 2.5 s and performs disturbance rejection within 3.0 s. Semi-autonomous manipulations were conducted in both a commercialized colonoscopy simulator and an ex-vivo porcine colon to show the efficacy of reducing the user workload compared to manual control.

CONCLUSION

The EAST colonoscope can perform visual servoing and semi-autonomous manipulations with the developed methods in both laboratory and ex-vivo environments.

SIGNIFICANCE

The proposed solutions and techniques improve the autonomy level of robotic colonoscopes and reduce user workloads, which promotes the development and clinical translation of robotic colonoscopy.

Comparison of fecal calprotectin levels and endoscopic scores for predicting relapse in patients with ulcerative colitis in remission

BACKGROUND

Although the usefulness of endoscopic scores, such as the Mayo Endoscopic Subscore (MES), Ulcerative Colitis Endoscopic Index of Severity (UCEIS), and Ulcerative Colitis Colonoscopic Index of Severity (UCCIS), and biomarkers such as fecal calprotectin (FC) for predicting relapse in ulcerative colitis (UC) has been reported, few studies have included endoscopic scores for evaluating the entire colon.

AIM

To compare the usefulness of FC value and MES, UCEIS, and UCCIS for predicting relapse in patients with UC in clinical remission.

METHODS

In total, 75 patients with UC in clinical and endoscopic remission who visited our institution between February 2019 and March 2022 were enrolled. The diagnosis of UC was confirmed based on the clinical presentation, endoscopic findings, and histology, according to the current established criteria for UC. Fecal samples were collected the day before or after the colonoscopy for measurement of FC. Endoscopic evaluations were performed using MES, UCEIS, and UCCIS. The primary outcome measure of this study was the assessment of the association between relapse within 12 mo and MES, UCEIS, UCCIS, and FC. The secondary outcome was the comparison between endoscopic scores and biomarkers in enrolled patients with UC with mucosal healing.

RESULTS

FC and UCCIS showed a significant correlation with UCEIS (r = 0.537, P < 0.001 and r = 0.957, P < 0.001, respectively). Receiver-operating characteristic analysis for predicting MES 0 showed that the area under the curve of UCCIS was significantly higher than that of FC (P < 0.01). During the 1-year observation period, 18 (24%) patients experienced a relapse, and both the FC and UCCIS of the relapse group were significantly higher than that of the remission group. The cut-off values for predicting relapse were set at FC = 323 mg/kg and UCCIS = 10.2. The area under the curve of the receiver-operating characteristic analysis for predicting relapse did not show a significant difference between FC and UCCIS. The accuracy of the endoscopic scores and biomarkers in predicting relapse was 86.7% for UCCIS, 85.3% for UCEIS, 76.0% for FC, and 73.3% for MES.

CONCLUSION

The three endoscopic scores and FC may predict UC relapse during clinical remission. Among these scores, UCEIS may be the most useful in terms of ease of evaluation and accuracy.

A retrospective study of colonoscopic surveillance in the elderly

BACKGROUND

Aotearoa New Zealand (AoNZ) guidelines suggest surveillance colonoscopy should be carefully considered after age 75. The authors noted a cluster of patients presenting in their 8th and 9th decade of life with a new colorectal cancer (CRC) having previously been declined surveillance colonoscopy.

METHODS

A 7-year retrospective analysis was performed of patients who underwent a colonoscopy aged between 71 and 75 years in the period between 2006 and 2012. Kaplan-Meier graphs were created with survival measured from the time of index colonoscopy. Log rank tests were used to determine any difference in survival distribution. Relative risk (RR) was calculated, and 95% confidence intervals (CI) reported.

RESULTS

A total of 623 patients met inclusion criteria; 461 (74%) had no indication for surveillance colonoscopy and 162 (26%) had an indication. Of the 162 patients with an indication, 91 (56.2%) underwent surveillance colonoscopies after the age of 75. Twenty-three (3.7%) patients were diagnosed with a new CRC. Eighteen (78.2%) patients diagnosed with a new CRC underwent surgery. The median survival overall was 12.9 years (95% CI 12.2-13.5). This did not differ between patients with (13.1, 95% CI 12.1-14.1) or without (12.6, 95% CI 11.2-14.0) an indication for surveillance.

CONCLUSION

This study found one quarter of patients who had a colonoscopy between the ages of 71-75 had an indication for surveillance colonoscopy. Most patients with a new CRC underwent surgery. This study suggests it may be appropriate to update the AoNZ guidelines and consider adopting a risk stratification tool to aid decision making.

Robotic endoscope with double-balloon and double-bend tube for colonoscopy

The insertion of conventional colonoscopes can sometimes cause patients to experience pain during the procedure owing to the stretching of the mesentery. In this study, a prototype of a robotic colonoscope with a double-balloon and double-bend tube based on the conventional double-balloon endoscope was developed to simplify insertion and prevent the overstretching of the colon. Both the outer and inner tubes were confirmed to be free from interference from wires and sheaths. Additionally, all functions such as tip bending, inflation and deflation of the balloons, and actuator-driven pulling and pushing of the inner tube were operated properly. During the insertion test, the device could be reached the cecum of a colon model in approximately 442 s when operated by a non-medical operator. In addition, the device did not overstretch the colon model, thereby suggesting that the insertion mechanism can follow the shape of the colon model. As a result, the developed mechanism has the potential to navigate through a highly-bent colon without overstretching.

Laparoscopic versus open surgery for colonoscopic perforation: A systematic review and meta-analysis

BACKGROUND

The efficacy of laparoscopic surgery (LS) for the treatment of colonoscopic perforation is still controversial. The purpose of this meta-analysis was to evaluate the effectiveness and safety of LS versus open surgery (OS) for colonoscopic perforation.

METHODS

All clinical trials that compared laparoscopic with OS for colonoscopic perforation published in English were identified in PubMed, EMBASE, Web of Science, and Cochrane Library searches. A modified scale was used to assess the quality of the literature. We analyzed the age, sex ratio, aim of colonoscopy, history of abdominopelvic surgery, type of procedure, size of perforation, operation time, postoperative fasting time, hospital stay, postoperative complication morbidity, and postoperative mortality. Meta-analyses were performed using weighted mean differences for continuous variables, and odds ratios for dichotomous variables.

RESULTS

No eligible randomized trials were identified, but eleven nonrandomized trials were analyzed. In the pooled data of 192 patients who underwent LS and 131 OS, there were no significant differences in age, sex ratio, aim of colonoscopy, history of abdominopelvic surgery, perforation size, and operative time between the groups. LS group had shorter time of hospital stay and postoperative fasting time, less postoperative complication morbidity, but there were no significant difference in postoperative mortality rate between LS group and OS group.

CONCLUSIONS

Based on the current meta-analysis, we conclude that LS is a safe and efficacious technique for colonoscopic perforation, with fewer postoperative complications, less hospital mortality, and faster recovery compared with OS.

Comparison of adenoma detection rate between high-definition colonoscopes with different fields of view: 170 degrees versus 140 degrees

In newer generation colonoscopes, the field of view (FOV) varies approximately between 170° and 140°, depending on the type of colonoscopy. To the best of our knowledge, no study has investigated whether the visual field difference of the colonoscope affects quality indicators, such as the adenoma detection rate (ADR), without using additional devices to expand the FOV in colonoscopes with the same resolution. This study aimed to investigate the difference in quality indicators, such as ADR, between 170° and 140° FOV in colonoscopes with the same high-definition resolution. We retrospectively analyzed the medical records of patients who underwent screening or surveillance colonoscopy at the Dong-A University Hospital in Busan, South Korea, between March 2021 and February 2022. We calculated the overall ADR ratios for patients who underwent colonoscopy with 140° and 170° FOV. Polyp detection rate (PDR), sessile serrated PDR, and advanced neoplasia detection rate were calculated for each group. Factors associated with adenoma detection were identified using a logistical regression analysis. A total of 1711 patients were included in the study (838 patients in the 170° group and 873 patients in the 140° group). ADR (43.79 vs 41.92%, P = .434) did not significantly differ between the 2 groups. The generational differences were not statistically significant either for PDR (56.44 vs 53.49%, P = .220), sessile serrated PDR (1.19 vs 0.92%, P = .575), or advanced neoplasia detection rate (5.00 vs 4.58%, P = .735). Multivariate regression analysis revealed that, age, male sex, and long withdrawal time were the most significant factors affecting adenoma detection. This study revealed that there were no differences in ADR while employing high definition colonoscopes with a 170° FOV and a 140° FOV.

Artificial intelligence-based assessments of colonoscopic withdrawal technique: a new method for measuring and enhancing the quality of fold examination

BACKGROUND

This study aimed to develop an artificial intelligence (AI)-based system for measuring fold examination quality (FEQ) of colonoscopic withdrawal technique. We also examined the relationship between the system's evaluation of FEQ and FEQ scores from experts, and adenoma detection rate (ADR) and withdrawal time of colonoscopists, and evaluated the system's ability to improve FEQ during colonoscopy.

METHODS

First, we developed an AI-based system for measuring FEQ. Next, 103 consecutive colonoscopies performed by 11 colonoscopists were collected for evaluation. Three experts graded FEQ of each colonoscopy, after which the recorded colonoscopies were evaluated by the system. We further assessed the system by correlating its evaluation of FEQ against expert scoring, historical ADR, and withdrawal time of each colonoscopist. We also conducted a prospective observational study to evaluate the system's performance in enhancing fold examination.

RESULTS

The system's evaluations of FEQ of each endoscopist were significantly correlated with experts' scores (r = 0.871, P < 0.001), historical ADR (r = 0.852, P = 0.001), and withdrawal time (r = 0.727, P = 0.01). For colonoscopies performed by colonoscopists with previously low ADRs (< 25 %), AI assistance significantly improved the FEQ, evaluated by both the AI system (0.29 [interquartile range (IQR) 0.27-0.30] vs. 0.23 [0.17-0.26]) and experts (14.00 [14.00-15.00] vs. 11.67 [10.00-13.33]) (both P < 0.001).

CONCLUSION

The system's evaluation of FEQ was strongly correlated with FEQ scores from experts, historical ADR, and withdrawal time of each colonoscopist. The system has the potential to enhance FEQ.

Robotic, self-propelled, self-steerable, and disposable colonoscopes: Reality or pipe dream? A state of the art review

Robotic colonoscopes could potentially provide a comfortable, less painful and safer alternative to standard colonoscopy. Recent exciting developments in this field are pushing the boundaries to what is possible in the future. This article provides a comprehensive review of the current work in robotic colonoscopes including self-propelled, steerable and disposable endoscopes that could be alternatives to standard colonoscopy. We discuss the advantages and disadvantages of these systems currently in development and highlight the technical readiness of each system to help the reader understand where and when such systems may be available for routine clinical use and get an idea of where and in which situation they can best be deployed.

Improved adenoma detection by a novel distal attachment device-assisted colonoscopy: a prospective randomized controlled trial

BACKGROUND AND AIMS

WingCap (A&A Medical Supply LLC, Seongnam, South Korea) is a novel distal attachment device for colonoscopy that combines a cap and an existing mucosal exposure device, such as Endocuff Vision (Arc Medical Design Ltd, Leeds, UK) and AmplifEYE (Medivators Inc, Minneapolis, Minn, USA). We aimed to investigate whether WingCap-assisted colonoscopy can improve the adenoma detection rate (ADR) and adenoma per colonoscopy (APC) and simultaneously shorten cecal intubation time compared with standard colonoscopy.

METHODS

We conducted a single-center, prospective, randomized controlled trial for outpatients aged ≥18 years undergoing colonoscopy. The primary outcome was ADR differences with the assistance of WingCap. Secondary outcomes were APC and other colonoscopy quality indicators, such as cecal intubation and withdrawal times.

RESULTS

In total, 537 patients were randomized for WingCap-assisted or standard colonoscopy. Their mean age was 59.3 years, and 48.5% were men. ADR was significantly higher in the WingCap group than in the control group (37.2% vs 26.6%, P = .012). APC was greater with WingCap than with standard colonoscopy (.72 ± 1.34 vs .45 ± 0.97, P = .008), prominently for nonpedunculated (.65 ± 1.25 vs .42 ± .95, P = .015) and diminutive (.42 ± .94 vs .20 ± .64, P = .002) adenomas. With WingCap, ADR and APC significantly increased for beginner endoscopists, whereas a modest increase was seen for experienced endoscopists. There were no differences in cecal intubation and withdrawal times between the 2 arms. No serious adverse event was associated with the use of WingCap.

CONCLUSIONS

WingCap-assisted colonoscopy was tolerable and efficacious for improving ADR and APC compared with standard colonoscopy, especially for nonpedunculated and diminutive adenomas and for beginner endoscopists. (Clinical trial registration number: KCT0005214.).

Management of acute colonic pseudo-obstruction in a neutropenic patient

Acute colonic pseudo-obstruction, also known as Ogilvie's syndrome, is a rare condition involving acute large bowel dilatation without mechanical obstruction. Management begins with conservative treatment and may include pharmacological therapy, colonoscopic decompression and surgery. Timely resolution is important due to the increased risk of bowel perforation and ischaemia associated with colonic dilatation. However, conditions such as neutropenia that place patients at an elevated risk of infection may limit treatment options. We report a case of acute colonic pseudo-obstruction in a neutropenic elderly man resistant to conservative measures and neostigmine and discuss the additional management considerations in an immunocompromised patient.

Colonoscope "Looping" During Ileo-Colonoscopy in Children is Significantly Different to that Observed in Adult Practice

OBJECTIVES

Ileo-colonoscopy (IC) can be technically challenging because of unpredictable colonoscope loop formation. Aims of this study were to assess the risk of loop formation and to attempt to understand which factors were likely to predispose to which subtype of loop.

METHODS

Prospective study conducted on children referred for an IC at Sheffield Children's Hospital. Presence and type of loop was objectively assessed using the magnetic endoscope imaging tool.

RESULTS

Three hundred procedures were prospectively evaluated. Only 9% of paediatric ICs were loop-free. Alpha loops were the most common loop in children older than 5, whereas reverse alpha loops and a wider variety of complex and repetitive loops were observed in younger patients. Once a specific type of loop has formed, the risk of re-looping in a different way or in a different position of the colon is reduced. Left lateral starting position was found to increase the risk of reverse alpha loops and re-looping. Challenging loops, such as reverse alpha, were more frequent in males. Higher body mass index (BMI) was associated with an increased risk of alpha and deep transverse loops formation, while lower BMI with a higher incidence of reverse alpha and N loop. Loop formation did not prevent 100% ileal intubation.

CONCLUSIONS

This study represents the first attempt to describe loop formation according to patient characteristics in a large paediatric series. Further studies are needed in order to establish if these findings could be helpful in simplifying the execution of IC procedures in children and facilitate the learning curve during endoscopy training programs.

A colonoscopic overtube system that creates a 'therapeutic zone' and permits retraction facilitates endoscopic submucosal dissection, was associated with fewer deep bowel wall injuries and instrument exchanges, and required less lifting solution vs classic endoscopic submucosal dissection in an ex vivo bovine model

INTRODUCTION

Endoscopic submucosal dissection (ESD) is the 'gold standard' for large flat polyps; nevertheless, the rate of adoption in the USA is low. In ESD, the polyp is 'surgically' detached with a needle knife after a submucosal lift; gravity and the dissection cap are used for retraction. ESD would be easier if active retraction were possible. In an ex vivo bovine colon model, this study assessed an overtube system (Boston Scientific ORISE Tissue Retraction System, TRS) that permits retraction and creates 'an operative field' for removal of rectal/sigmoid lesions.

METHOD

Classic ESD (C-ESD) was compared to TRS-facilitated ESD (TRS-ESD). Cleaned/preserved bovine large bowel was used, and two 2-cm 'lesions'/colon were branded onto the mucosal surface 25 and 35 cm from the anus. Submucosal saline lifts were made using a thin catheter and a standard needle knife. We tracked case length, number of instrument exchanges (to refresh lift), the volume of lift solution, the fullness of resection, and deep muscle injuries.

RESULTS

Fifty ESDs were carried out in 25 colons (25 C-ESD, 25 TRS-ESD). Complete resections were noted in all cases. The TRS method required fewer instrument exchanges (median 5) vs C-ESD (median 9, p < 0.0001) and less lift solution (median 39 ml) than the C-ESD cases (median 55 ml, p = 0.0003). TRS-ESD was associated with fewer deep muscle injuries (median 2) than C-ESD (median 3, p = 0.0191). Finally, the TRS group's median case length (34.5 min) was shorter than that of C-ESD (41 min, p = 0.0543).

CONCLUSION

The TRS system provides retraction and facilitates ESD regarding the number of lift injections, the volume of lift solution needed, and avoidance of muscle injuries. Of note, there is an apparent TRS learning curve, and the device mandates a distal-to-proximal approach and initial 360 degree mucosal incision. Further study is warranted.

Unsupervised Monocular Depth Estimation for Colonoscope System Using Feedback Network

A colonoscopy is a medical examination used to check disease or abnormalities in the large intestine. If necessary, polyps or adenomas would be removed through the scope during a colonoscopy. Colorectal cancer can be prevented through this. However, the polyp detection rate differs depending on the condition and skill level of the endoscopist. Even some endoscopists have a 90% chance of missing an adenoma. Artificial intelligence and robot technologies for colonoscopy are being studied to compensate for these problems. In this study, we propose a self-supervised monocular depth estimation using spatiotemporal consistency in the colon environment. It is our contribution to propose a loss function for reconstruction errors between adjacent predicted depths and a depth feedback network that uses predicted depth information of the previous frame to predict the depth of the next frame. We performed quantitative and qualitative evaluation of our approach, and the proposed FBNet (depth FeedBack Network) outperformed state-of-the-art results for unsupervised depth estimation on the UCL datasets.

Recent advances in colonoscopy

Colonoscopy continues to evolve as equipment and techniques improve. Traditionally, colonoscopy has focused on adenoma detection, characterisation and resection as the primary aims, and there has certainly been considerable activity over the last few years in terms of addressing these important issues. This review article not only will discuss progress made in these areas but also will focus on when to colonoscope in terms of introduction of faecal immunochemical testing, how to insert with the advent of water-assisted insertion, and how to withdraw using a bundle of evidence-based techniques to improve adenoma detection. In addition, the ramifications of failing to discover polyps and of post-colonoscopy colorectal cancer are highlighted.

Autofluorescence Imaging Reflects the Nuclear Enlargement of Tumor Cells as well as the Cell Proliferation Ability and Aberrant Status of the p53, Ki-67, and p16 Genes in Colon Neoplasms

BACKGROUND

Autofluorescence imaging (AFI) is useful for diagnosing colon neoplasms, but what affects the AFI intensity remains unclear. This study investigated the association between AFI and the histological characteristics, aberrant methylation status, and aberrant expression in colon neoplasms.

METHODS

Fifty-three patients with colorectal neoplasms who underwent AFI were enrolled. The AFI intensity (F index) was compared with the pathological findings and gene alterations. The F index was calculated using an image analysis software program. The pathological findings were assessed by the tumor crypt density, cell densities, and N/C ratio. The aberrant methylation of p16, E-cadherin, Apc, Runx3, and hMLH1 genes was determined by a methylation-specific polymerase chain reaction. The aberrant expression of p53 and Ki-67 was evaluated by immunohistochemical staining.

RESULTS

An increased N/C ratio, the aberrant expression of p53, Ki-67, and the altered methylation of p16 went together with a lower F index. The other pathological findings and the methylation status showed no association with the F index.

CONCLUSIONS

AFI reflects the nuclear enlargement of tumor cells, the cell proliferation ability, and the altered status of cell proliferation-related genes, indicating that AFI is a useful and practical method for predicting the dysplastic grade of tumor cells and cell proliferation.

Effect of Endocuff use on colonoscopy outcomes: A systematic review and meta-analysis

BACKGROUND

Endocuff - a plastic device with flexible projections - mounted on the distal tip of the colonoscope, promises improved colonic mucosa inspection.

AIM

To elucidate the effect of Endocuff on adenoma detection rate (ADR), advanced ADR (AADR) and mean number of adenomas per colonoscopy (MAC).

METHODS

Literature searches identified randomized-controlled trials evaluating Endocuff-assisted colonoscopy (EAC) vs conventional colonoscopy (CC) in terms of ADR, AADR and MAC. The effect size on study outcomes was calculated using fixed or random effect model, as appropriate, and it is shown as relative risk (RR) [95% confidence interval (CI)] and mean difference (MD) (95%CI). The rate of device removal in EAC arms was also calculated.

RESULTS

We identified nine studies enrolling 6038 patients. All studies included mixed population (screening, surveillance and diagnostic examinations). Seven and two studies evaluated the first and the second-generation device, respectively. EAC was associated with increased ADR compared to CC [RR (95%CI): 1.18 (1.05-1.32); Ι² = 71%]; EAC benefits more endoscopists with ADR ≤ 35% compared to those with ADR > 35% [RR (95%CI): 1.37 (1.08-1.74); Ι² = 49% vs 1.10 (0.99-1.24); Ι² = 71%]. In terms of AADR and MAC, no difference was detected between EAC and CC [RR (95%CI): 1.03 (0.85-1.25); Ι² = 15% and MD (95%CI): 0.30 (-0.17-0.78); Ι² = 99%]. Subgroup analysis did not show any difference between the two device generations regarding all three endpoints. In EAC arms, the device had to be removed in 3% (95%CI: 2%-5%) of the cases mainly due to tortuous sigmoid or presence of diverticula along it.

CONCLUSION

EAC increases ADR compared to CC, especially for endoscopists with lower ADR. On the other hand, no significant effect on AADR and MAC was detected.

Colonoscopy attachments for the detection of precancerous lesions during colonoscopy: A review of the literature

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.

Fecal marker levels as predictors of need for endoscopic balloon dilation in Crohn’s disease patients with anastomotic strictures

AIM

To evaluate the accuracy and best cut-off value of fecal calprotectin (FC) and fecal lactoferrin (FL) to predict disease recurrence in asymptomatic patients presenting with anastomotic strictures.

METHODS

This was a longitudinal single tertiary center study based on prospectively collected data (recorded in a clinical database created for this purpose) performed between March 2010 and November 2014. Crohn’s disease (CD) patients with anastomotic stricture who submitted to postoperative endoscopic evaluation were included. Stools were collected on the day before bowel cleaning for FC and FL. Endoscopic balloon dilation (EBD) was performed if the patient presented an anastomotic stricture not traversed by the colonoscope, regardless of patients’ symptoms. Successful dilation was defined as passage of the colonoscope through the dilated stricture into the neotermimal ileum. Postoperative recurrence was defined as a modified Rutgeerts score of ≥ i2b.

RESULTS

In a total of 178 patients who underwent colonoscopy, 58 presented an anastomotic stricture, 86% were asymptomatic, and 48 (54% male; median age of 46.5 years) were successfully dilated. Immediate success rate was 92% and no complications were recorded. FC and FL levels correlated significantly with endoscopic recurrence (P < 0.001) with an optimal cut-off value of 90.85 µg/g (sensitivity of 95.5%, specificity of 69.2%, positive predictive value (PPV) of 72.4%, negative predictive value (NPV) of 94.7% and accuracy of 81%] for FC and of 5.6 µg/g (sensitivity of 77.3%, specificity of 69.2%, PPV of 68%, NPV of 78.4% and accuracy of 72.9%) for FL.

CONCLUSION

Fecal markers are good predictors of CD endoscopic recurrence in patients with asymptomatic anastomotic stricture. FC and FL may guide the need for EBD in this context.

Study to determine guidelines for pediatric colonoscopy

AIM

To investigated characteristics, diagnosis, bowel-cleansing preparation, sedation, and colonoscope length and diameter in Japanese pediatric patients receiving total colonoscopy.

METHODS

The present study evaluated consecutive patients aged ≤ 15 years who had undergone their first colonoscopy in Kurume University between January 2007 and February 2015. Data were retrospectively analyzed. We identified 110 pediatric patients who had undergone colonoscopy that had reached the cecum, allowing the observation of the total colon.

RESULTS

Hematochezia, abdominal pain, and diarrhea were the most common symptoms. For bowel-cleansing preparation, pediatric patients aged ≤ 12 years were treated with magnesium citrate, and patients aged 13-15 years were treated with polyethylene glycol 4000. For sedation, thiamylal with pentazocine, which has an analgesic effect, was used in patients aged ≤ 6 years, and midazolam with pentazocine was used in patients aged ≥ 7 years. Regarding the choice of endoscope, short and thin endoscopes were selected for younger patients, particularly patients aged ≤ 3 years. Positive diagnoses were made in 78 patients (70.9%). Inflammatory bowel disease (n = 49, 44.5%), including ulcerative colitis (n = 37, 33.6%) and Crohn’s disease (n = 12, 10.9%), was the most common diagnosis.

CONCLUSION

Colonoscopy offers a high diagnostic capability for pediatric patients with gastrointestinal symptoms. The selection of appropriate management the performance of colonoscopy is important in pediatric patients.

New endoscopes and add-on devices to improve colonoscopy performance

Colonoscopy is the gold standard for colorectal cancer prevention; however, it is still an imperfect modality. Precancerous lesions can be lost during screening examinations, thus increasing the risk of interval cancer. A variety of factors either patient-, or endoscopist dependent or even the procedure itself may contribute to loss of lesions. Sophisticated modalities including advanced technology endoscopes and add-on devices have been developed in an effort to eliminate colonoscopy's drawbacks and maximize its ability to detect potentially culprit polyps. Novel colonoscopes aim to widen the field of view. They incorporate more than one cameras enabling simultaneous image transmission. In that way the field of view can expand up to 330°. On the other hand a plethora of add-on devices attachable on the standard colonoscope promise to detect lesions in the proximal aspect of colonic folds either by offering a retrograde view of the lumen or by straightening the haustral folds during withdrawal. In this minireview we discuss how these recent advances affect colonoscopy performance by improving its quality indicators (cecal intubation rate, adenoma detection rate) and other metrics (polyp detection rate, adenomas per colonoscopy, polyp/adenoma miss rate) associated with examination's outcomes.

Longitudinal assessment of reprocessing effectiveness for colonoscopes and gastroscopes: Results of visual inspections, biochemical markers, and microbial cultures

BACKGROUND

Flexible endoscopes are currently reused following cleaning and high-level disinfection. Contamination has been found on endoscopes, and infections have been linked to gastrointestinal, respiratory, and urologic endoscopes.

METHODS

This longitudinal study involved visual inspections with a borescope, microbial cultures, and biochemical tests for protein and adenosine triphosphate to identify endoscopes in need of further cleaning or maintenance. Three assessments were conducted over a 7-month period. Control group endoscopes reprocessed using customary practices were compared with intervention group endoscopes subjected to more rigorous reprocessing.

RESULTS

At final assessment, all endoscopes (N = 20) had visible irregularities. Researchers observed fluid (95%), discoloration, and debris in channels. Of 12 (60%) endoscopes with microbial growth, 4 had no growth until after 48 hours. There were no significant differences in culture results by study group, assessment period, or endoscope type. Similar proportions of control and intervention endoscopes (~20%) exceeded postcleaning biochemical test benchmarks. Adenosine triphosphate levels were higher for gastroscopes than colonoscopes (P = .014). Eighty-five percent of endoscopes required repair due to findings.

CONCLUSIONS

More rigorous reprocessing was not consistently effective. Seven-day incubation allowed identification of slow-growing microbes. These findings bolster the need for routine visual inspection and cleaning verification tests recommended in new reprocessing guidelines.

Development of a Robotic Colonoscopic Manipulation System, Using Haptic Feedback Algorithm

PURPOSE

Colonoscopy is one of the most effective diagnostic and therapeutic tools for colorectal diseases. We aim to propose a master-slave robotic colonoscopy that is controllable in remote site using conventional colonoscopy.

MATERIALS AND METHODS

The master and slave robot were developed to use conventional flexible colonoscopy. The robotic colonoscopic procedure was performed using a colonoscope training model by one expert endoscopist and two unexperienced engineers. To provide the haptic sensation, the insertion force and the rotating torque were measured and sent to the master robot.

RESULTS

A slave robot was developed to hold the colonoscopy and its knob, and perform insertion, rotation, and two tilting motions of colonoscope. A master robot was designed to teach motions of the slave robot. These measured force and torque were scaled down by one tenth to provide the operator with some reflection force and torque at the haptic device. The haptic sensation and feedback system was successful and helpful to feel the constrained force or torque in colon. The insertion time using robotic system decreased with repeated procedures.

CONCLUSION

This work proposed a robotic approach for colonoscopy using haptic feedback algorithm, and this robotic device would effectively perform colonoscopy with reduced burden and comparable safety for patients in remote site.

The Effects of Irreversible Electroporation on the Colon in a Porcine Model

Background and Aim

Irreversible electroporation (IRE) is a method of targeted cell ablation which has been suggested as a potential cancer therapy as it leaves structures such as blood vessels and the extracellular matrix intact, thereby allowing the rapid recovery of healthy tissue. Here, we investigated the effects of IRE on the colon in vivo in a porcine model.

Methods

IRE ablation was performed on the colon walls of 12 female Tibet mini-pigs, creating a total of 24 lesions. Lesions were monitored periodically by endoscopy. The pigs were euthanized 7, 14, 21 or 28 days after IRE ablation and the colons harvested for gross and histological analysis. Sections were stained with hematoxylin and eosin (H&E), Masson’s trichrome (MT) stain and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay.

Results

All pigs tolerated the ablation procedure without serious clinical symptoms or complications. There was no evidence of perforation by endoscopy or gross postmortem examination. All lesions were characterized by necrotic cell death with mild inflammation and hyperemia, with a sharp demarcation between ablated and adjacent normal tissue. A fibrous scar was observed in the ablated colon tissue. Histological analysis revealed damage to each layer of the colon. Histopathology findings also showed the preservation of extracellular structures and the recovery of the ablated colon.

Conclusions

The complete ablation of the target area, its rapid recovery and the lack of posttreatment symptoms suggest that IRE ablation may be a promising therapy for tumors located adjacent to or violating the colon wall.

Use of the Endocuff during routine colonoscopy examination improves adenoma detection: A meta-analysis

AIM

To perform meta-analysis of the use of Endocuff during average risk screening colonoscopy.

METHODS

Scopus, Cochrane databases, MEDLINE/PubMed, and CINAHL were searched in April 2016. Abstracts from Digestive Disease Week, United European Gastroenterology, and the American College of Gastroenterology meeting were also searched from 2004-2015. Studies comparing EC-assisted colonoscopy (EAC) to standard colonoscopy, for any indication, were included in the analysis. The analysis was conducted by using the Mantel-Haenszel or DerSimonian and Laird models with the odds ratio (OR) to assess adenoma detection, cecal intubation rate, and complications performed.

RESULTS

Nine studies (n = 5624 patients) were included in the analysis. Compared to standard colonoscopy, procedures performed with EC had higher frequencies for adenoma (OR = 1.49, 95%CI: 1.23-1.80; P = 0.03), and sessile serrated adenomas detection (OR = 2.34 95%CI: 1.63-3.36; P < 0.001). There was no significant difference in cecal intubation rates between the EAC group and standard colonoscopy (OR = 1.26, 95%CI: 0.70-2.27, I2 = 0%; P = 0.44). EAC was associated with a higher risk of complications, most commonly being superficial mucosal injury without higher frequency for perforation.

CONCLUSION

The use of an EC on colonoscopy appears to improve pre-cancerous polyp detection without any difference in cecal intubation rates compared to standard colonoscopy.

Long-term detection of seasonal influenza RNA in faeces and intestine

Some cases of seasonal influenza virus (human influenza A virus (IAV)/human influenza B virus (IBV)) are associated with abdominal symptoms. Although virus RNA has been detected in faeces, intestinal infection has not been clearly demonstrated. We aimed to provide evidence that IAV/IBV infects the human intestine. This prospective observational study measured virus RNA in faecal and sputum samples from 22 patients infected with IAV/IBV (19 IAV positive and three IBV positive). Nineteen patients were included in the analysis and were assigned to faecal IAV-positive and -negative groups. Virus kinetics were examined in faecal samples from an IAV-infected patient (patient 1) and an IBV-infected patient (patient 2). Finally, intestinal tissue from an IAV-diagnosed patient who developed haemorrhagic colitis and underwent colonoscopy was examined for the presence of replicating IAV (patient 3). Virus RNA was detected in faecal samples from 8/22 IAV/IBV-infected patients (36.4%). Diarrhoea occurred significantly more often in the faecal IAV-positive group (p 0.002). In patients 1 and 2, virus RNA became undetectable in sputum on days 7 and 10 after infection, respectively, but was detected in faeces for a further 2 weeks. Virus mRNA and antigens were detected in intestinal tissues (mucosal epithelium of the sigmoid colon) from patient 3. These findings suggest that IAV/IBV infects within the intestinal tract; thus, the human intestine may be an additional target organ for IAV/IBV infection.

Automated visibility map of the internal colon surface from colonoscopy video

PURPOSE

Optical colonoscopy is a prominent procedure by which clinicians examine the surface of the colon for cancerous polyps using a flexible colonoscope. One of the main concerns regarding the quality of the colonoscopy is to ensure that the whole colonic surface has been inspected for abnormalities. In this paper, we aim at estimating areas that have not been covered thoroughly by providing a map from the internal colon surface.

METHODS

Camera parameters were estimated using optical flow between consecutive colonoscopy frames. A cylinder model was fitted to the colon structure using 3D pseudo stereo vision and projected into each frame. A circumferential band from the cylinder was extracted to unroll the internal colon surface (band image). By registering these band images, drift in estimating camera motion could be reduced, and a visibility map of the colon surface could be generated, revealing uncovered areas by the colonoscope. Hidden areas behind haustral folds were ignored in this study. The method was validated on simulated and actual colonoscopy videos. The realistic simulated videos were generated using a colonoscopy simulator with known ground truth, and the actual colonoscopy videos were manually assessed by a clinical expert.

RESULTS

The proposed method obtained a sensitivity and precision of 98 and 96 % for detecting the number of uncovered areas on simulated data, whereas validation on real videos showed a sensitivity and precision of 96 and 78 %, respectively. Error in camera motion drift could be reduced by almost 50 % using results from band image registration.

CONCLUSION

Using a simple cylindrical model for the colon and reducing drift by registering band images allows for the generation of visibility maps. The current results also suggest that the provided feedback through the visibility map could enhance clinicians' awareness of uncovered areas, which in return could reduce the probability of missing polyps.

Can optical diagnosis of small colon polyps be accurate? Comparing standard scope without narrow banding to high definition scope with narrow banding

AIM: To study the accuracy of using high definition (HD) scope with narrow band imaging (NBI) vs standard white light colonoscope without NBI (ST), to predict the histology of the colon polyps, particularly those < 1 cm.

METHODS: A total of 147 African Americans patients who were referred to Howard University Hospital for screening or, diagnostic or follow up colonoscopy, during a 12-mo period in 2012 were prospectively recruited. Some patients had multiple polyps and total number of polyps was 179. Their colonoscopies were performed by 3 experienced endoscopists who determined the size and stated whether the polyps being removed were hyperplastic or adenomatous polyps using standard colonoscopes or high definition colonoscopes with NBI. The histopathologic diagnosis was reported by pathologists as part of routine care.

RESULTS: Of participants in the study, 55 (37%) were male and median (interquartile range) of age was 56 (19-80). Demographic, clinical characteristics, past medical history of patients, and the data obtained by two instruments were not significantly different and two methods detected similar number of polyps. In ST scope 89% of polyps were < 1 cm vs 87% in HD scope (P = 0.7). The ST scope had a positive predictive value (PPV) and positive likelihood ratio (PLR) of 86% and 4.0 for adenoma compared to 74% and 2.6 for HD scope. There was a trend of higher sensitivity for HD scope (68%) compare to ST scope (53%) with almost the same specificity. The ST scope had a PPV and PLR of 38% and 1.8 for hyperplastic polyp (HPP) compared to 42% and 2.2 for HD scope. The sensitivity and specificity of two instruments for HPP diagnosis were similar.

CONCLUSION: Our results indicated that HD scope was more sensitive in diagnosis of adenoma than ST scope. Clinical diagnosis of HPP with either scope is less accurate compared to adenoma. Colonoscopy diagnosis is not yet fully matched with pathologic diagnosis of colon polyp. However with the advancement of both imaging and training, it may be possible to increase the sensitivity and specificity of the scopes and hence save money for eliminating time and the cost of Immunohistochemistry/pathology.

Can Technology Improve the Quality of Colonoscopy?

In order for screening colonoscopy to be an effective tool in reducing colon cancer incidence, exams must be performed in a high-quality manner. Quality metrics have been presented by gastroenterology societies and now include higher adenoma detection rate targets than in the past. In many cases, the quality of colonoscopy can often be improved with simple low-cost interventions such as improved procedure technique, implementing split-dose bowel prep, and monitoring individuals' performances. Emerging technology has expanded our field of view and image quality during colonoscopy. We will critically review several technological advances in the context of quality metrics and discuss if technology can really improve the quality of colonoscopy.

Black hood assisted colonoscopy for detection of colorectal polyps: a prospective randomized controlled study

OBJECTIVE

Colonoscopy is considered as a standard method for detecting various kinds of colorectal polyps. However, conventional colonoscopy (CC) still has chances to miss some lesions. Some scholars have already reported that transparent hood assisted colonoscopy (THAC) can improve the detection rate of colorectal polyps. However, the efficacy of detection of colorectal polyps with black hood assisted colonoscopy (BHAC) is still unclear. In this study, BHAC was compared with CC for evaluating the efficacy of detection of colorectal polyps.

PATIENTS AND METHODS

Between Sep 2014 and Apr 2015, 542 patients underwent CC and meanwhile 534 patients underwent BHAC were enrolled into this prospective randomized controlled study. Comparison of baseline characteristics, cecal intubation time, withdrawal time, total number of detected polyps, detection rate of polyps, location, size, morphology and pathological diagnosis of polyps between these two groups was performed.

RESULTS

Cecal intubation time was significantly shorter in BHAC group than in CC group (6.31 ± 3.51 min vs. 7.05 ± 4.15 min, p = 0.002). The total number of detected polyps and detection rate of polyps were significantly higher in BHAC group than in CC group (349/65.36% vs. 264/48.71%, p = 0.004).

CONCLUSIONS

Compared with CC, BHAC could significantly improve the detection rate of colorectal polyps, and cecal intubation time was significantly reduced by BHAC.

Feasibility of full-spectrum endoscopy: Korea’s first full-spectrum endoscopy colonoscopic trial

AIM: To evaluate the full-spectrum endoscopy (FUSE) colonoscopy system as the first report on the utility thereof in a Korean population.

METHODS: We explored the efficacy of the FUSE colonoscopy in a retrospective, single-center feasibility study performed between February 1 and July 20, 2015. A total of 262 subjects (age range: 22-80) underwent the FUSE colonoscopy for colorectal cancer screening, polyp surveillance, or diagnostic evaluation. The cecal intubation success rate, the polyp detection rate (PDR), the adenoma detection rate (ADR), and the diverticulum detection rate (DDR), were calculated. Also, the success rates of therapeutic interventions were evaluated with biopsy confirmation.

RESULTS: All patients completed the study and the success rates of cecal and terminal ileal intubation were 100% with the FUSE colonoscope; we found 313 polyps in 142 patients and 173 adenomas in 95. The overall PDR, ADR and DDR were 54.2%, 36.3%, and 25.2%, respectively, and were higher in males, and increased with age. The endoscopists and nurses involved considered that the full-spectrum colonoscope improved navigation and orientation within the colon. No colonoscopy was aborted because of colonoscope malfunction.

CONCLUSION: The FUSE colonoscopy yielded a higher PDR, ADR, DDR than did traditional colonoscopy, without therapeutic failure or complications, showing feasible, effective, and safe in this first Korean trial.

Diagnostic value of high-resolution micro-endoscopy for the classification of colon polyps

AIM: To study a new imaging equipment, high-resolution micro-endoscopy (HRME), in the diagnosis and pathological classification of colon polyps.

METHODS: We selected 114 specimens of colon polyps, 30 of which were colon polyps with known pathological types and 84 that were prospective polyp specimens; 10 normal colon mucosa specimens served as controls. We obtained images of 30 colon polyp specimens with known pathological types using HRME and analyzed the characteristics of these images to develop HRME diagnostic criteria for different pathological types of colon polyps. Based on these criteria, we performed a prospective study of 84 colon polyp specimens using HRME and compared the results with those of the pathological examination to evaluate the diagnostic value of HRME in the pathological classification of different types of colon polyps.

RESULTS: In the 30 cases of known pathological type of colon polyp samples, there were 21 cases of adenomatous polyps, which comprised nine cases of tubular adenoma, seven cases of villous adenoma and five cases of mixed adenomas. The nine cases of non-adenomatous polyps included four cases of inflammatory polyps and five cases of hyperplastic polyps five. Ten cases of normal colonic mucosa were confirmed pathologically. In a prospective study of 84 cases using HRME, 23 cases were diagnosed as inflammatory polyps, 11 cases as hyperplastic polyps, 18 cases as tubular adenoma, eight cases as villous adenoma and 24 cases as mixed adenomas. After pathological examination, 24 cases were diagnosed as inflammatory polyps, 11 cases as hyperplastic polyps, 19 cases as tubular adenoma, eight cases as villous adenoma and 22 cases as mixed adenomas. Compared with the pathological examinations, the sensitivities, specificities, accuracies, and positive and negative predictive values of HRME in diagnosing inflammatory polyps (87.5%, 96.7%, 94.0%, 91.3% and 95.1%), hyperplastic polyps (72.7%, 95.9%, 92.9%, 72.7% and 95.9%), tubular adenomas (73.7%, 93.8%, 89.3%, 77.8% and 92.4%), villous adenomas (75.0%, 97.4%, 95.2%, 75.0% and 97.4%), and mixed adenomas (75.0%, 93.3%, 88.1%, 81.8% and 90.3%) were relatively high.

CONCLUSION: HRME has a relatively high diagnostic value in the pathological classification of colon polyps. Thus, it may be an alternative to confocal microendoscopy in lower-resource or community-based settings.

A competency framework for colonoscopy training derived from cognitive task analysis techniques and expert review

BACKGROUND

Colonoscopy is a difficult cognitive-perceptual-motor task. Designing an appropriate instructional program for such a task requires an understanding of the knowledge, skills and attitudes underpinning the competency required to perform the task. Cognitive task analysis techniques provide an empirical means of deriving this information.

METHODS

Video recording and a think-aloud protocol were conducted while 20 experienced endoscopists performed colonoscopy procedures. "Cued-recall" interviews were also carried out post-procedure with nine of the endoscopists. Analysis of the resulting transcripts employed the constant comparative coding method within a grounded theory framework. The resulting draft competency framework was modified after review during semi-structured interviews conducted with six expert endoscopists.

RESULTS

The proposed colonoscopy competency framework consists of twenty-seven skill, knowledge and attitude components, grouped into six categories (clinical knowledge; colonoscope handling; situation awareness; heuristics and strategies; clinical reasoning; and intra- and inter-personal).

CONCLUSIONS

The colonoscopy competency framework provides a principled basis for the design of a training program, and for the design of formative assessment to gauge progress towards attaining the knowledge, skills and attitudes underpinning the achievement of colonoscopy competence.

New endoscopic platform for endoluminal en bloc tissue resection in the gastrointestinal tract (with videos)

BACKGROUND

Endoscopic removal of gastrointestinal tract lesions is increasingly popular around the world. We evaluated feasibility, safety, effectiveness, and user learning curve of new endoscopic platform for complex intraluminal interventions.

METHODS

A novel system, consisting of expandable working chamber with two independent instrument guides (LIG), was inserted into colon. Simulated colonic lesions were removed with endoscopic submucosal (ESD) and submuscular (ESmD) dissection.

RESULTS

In all nine in vivo models, an intraluminal chamber and its dynamic tissue retractors (via LIG) provided a stable working space with excellent visualization and adequate access to target tissue. Endoscopic platform facilitated successful completion of 11 en bloc ESDs (mean size 43.0 ± 11.3 mm, mean time 46.3 ± 41.2 min) and eight ESmD (mean size 50.0 ± 14.1 mm, mean time 48.0 ± 21.2 min). The learning curve for ESD using this platform demonstrated three phases: rapid improvement in procedural skills took place during the first three procedures (mean ESD time 98.7 ± 40.0 min). A plateau phase then occurred (procedures 4-7) with mean procedure time 42.0 ± 13.4 min (p = 0.04), followed by another sharp improvement in procedural skills (procedures 8-11) requiring only 16.3 ± 11.4 min (p = 0.03) to complete ESD. Especially dramatic (p = 0.002) was the time difference between the first three procedures (mean time 98.7 ± 40.0 min) and subsequent eight procedures (mean time 29.1 ± 17.9 min).

CONCLUSIONS

A newly developed endoscopic platform provides stable intraluminal working space, dynamic tissue retraction, and instrument triangulation, improving visualization and access to the target tissue for safer and more effective en bloc endoscopic submucosal and submuscular dissection. The learning curve for ESD was markedly facilitated by this new endoscopic platform.

Expanding the view of a standard colonoscope with the Third Eye® Panoramic™ cap

AIM: To evaluate a new imaging device for colonoscopy that adds two side viewing CMOS lenses, the Third Eye^® Panoramic™ cap.

METHODS: In this prospective observational feasibility study, 33 patients, 18 male and 15 female, underwent routine screening, surveillance or diagnostic colonoscopy with the new Third Eye^® Panoramic™ cap clipped on to the distal tip of a high definition Fuji EC530-LS Slim Colonoscope^®. All procedures were performed at the New York Presbyterian-Queens Endoscopy unit by two experienced endoscopists (Rubin M and Kim SH). Main outcome measurements included evaluation of the image quality of the Third Eye^® Panoramic™ cap, adenoma detection rate, cecal intubation rate, withdrawal time and total procedure time.

RESULTS: The Third Eye^® Panoramic™ cap enabled enhanced views without affecting the quality of the colonoscope’s image or its handling characteristics through the colon. Ileal intubation was accomplished in most cases, but was more challenging. The side view lenses detected polyps and diverticula hidden behind folds and in flexures not seen on the standard view. The side view lenses were easily cleaned utilizing an Endogator^® Irrigation Pump (Medivators, Minneapolis, MN, United States) by angling the scope tip against the mucosa while washing. The cecum was reached in all 33 patients. Mean cecal intubation time was 8.19 ± 2.17 min, mean withdrawal time was 10.15 ± 5.56 min and mean total procedure time was 20.31 ± 5.14 min. The overall adenoma detection rate was 44%.

CONCLUSION: The Third Eye^® Panoramic™ cap enables wide view colonoscopy with enhanced visualization utilizing standard forward view colonoscopes.

When and why a colonoscopist should discontinue colonoscopy by himself?

AIM: To investigate when and why a colonoscopist should discontinue incomplete colonoscopy by himself.

METHODS: In this cross-sectional study, 517 difficult colonoscope insertions (Grade C, Kudo’s difficulty classification) screened from 37800 colonoscopy insertions were collected from April 2004 to June 2014 by three 4^th-level (Kudo’s classification) colonoscopists. The following common factors for the incomplete insertion were excluded: structural obstruction of the colon or rectum, insufficient colon cleansing, discontinuation due to patient’s discomfort or pain, severe colon disease with a perforation risk (e.g., severe ischemic colonopathy). All the excluded patients were re-scheduled if permission was obtained from the patients whose intubation had failed. If the repeat intubations were still a failure because of the difficult operative techniques, those patients were also included in this study. The patient’s age, sex, anesthesia and colonoscope type were recorded before colonoscopy. During the colonoscopic examination, the influencing factors of fixation, tortuosity, laxity and redundancy of the colon were assessed, and the insertion time (> 10 min or ≤ 10 min) were registered. The insertion time was analyzed by t-test, and other factors were analyzed by univariate and multivariate logistic regression.

RESULTS: Three hundred and twenty-two (62.3%) of the 517 insertions were complete in the colonoscope insertion into the ileocecum, but 195 (37.7%) failed in the insertion. Fixation, tortuosity, laxity or redundancy occurred during the colonoscopic examination. Multivariate logistic regression analysis revealed that fixation (OR = 0.06, 95%CI: 0.03-0.16, P < 0.001) and tortuosity (OR = 0.04, 95%CI: 0.02-0.08, P < 0.001) were significantly related to the insertion into the ileocecum in the left hemicolon; multivariate logistic regression analysis also revealed that fixation (OR = 0.16, 95%CI: 0.06-0.39, P < 0.001), tortuosity (OR 0.23, 95%CI: 0.13-0.43, P < 0.001), redundancy (OR = 0.12, 95%CI: 0.05-0.26, P < 0.001) and sex (OR = 0.35, 95%CI: 0.20-0.63, P < 0.001) were significantly related to the insertion into the ileocecum in the right hemicolon. Prolonged insertion time (> 10 min) was an unfavorable factor for the insertion into the ileocecum.

CONCLUSION: Colonoscopy should be discontinued if freedom of the colonoscope body’s insertion and rotation is completely lost, and the insertion time is prolonged over 30 min.

Preliminary study of photodynamic diagnosis using 5-aminolevulinic acid in gastric and colorectal tumors

AIM: To investigate the utility of photodynamic diagnosis (PDD) using 5-aminolevulinic acid (5-ALA) to detect gastric/colorectal tumors.

METHODS: This prospective single-center study investigated inter-subject variability in patients with early-stage gastric/colorectal tumor indicated for endoscopic resection. Subjects were patients with gastric or colorectal tumors who had undergone endoscopic resection between November 2012 and November 2013. Selection criteria included age 20-80 years, either sex, and provision of informed consent. Patients were orally administered 20 mg/kg of 5-ALA enteric-coated capsules (SBI ALApromo Co., Tokyo, Japan). Administration of 5-ALA was followed by endoscopic resection of gastric or colorectal tumors, and the resected specimens were examined using a video autofluorescence processor and a fluorescence endoscope (SAFE-3000 and EB-1970AK, respectively; Pentax, Tokyo, Japan). The primary endpoint was the presence of fluorescence in tumors. Endoscopic, macroscopic, and histopathologic findings of tumors were assessed. We also evaluated adverse events of the present procedure as a secondary endpoint and examined each patient for the presence of known adverse effects of 5-ALA, namely, hematocytopenia, liver dysfunction, hypotension, nausea, and photosensitivity.

RESULTS: We enrolled 10 patients (7 men, 3 women) (n = 13 lesions: 10 gastric/3 colorectal tumors). Fluorescence was detected in 7/13 (53.8%) lesions. No significant differences in sex (male: 55.6% vs female: 50.5%, P = 1.00), age (67.1 ± 1.9 years vs 65.0 ± 2.0 years, P = 0.45), tumor color (reddish: 60.0% vs discolored: 33.3%, P = 0.56), tumor diameter (15.0 ± 2.1 mm vs 14.2 ± 2.3 mm, P = 0.80), macroscopic type (protruded: 70.0% vs depressed 0%, P = 0.07), histologic type (differentiated type: 58.3% vs 0%, P = 0.46), invasion depth (mucosal layer: 55.6% vs submucosal layer: 33.3%, P = 1.00), lymphatic invasion (present: 33.3% vs absent: 50.0%, P = 1.00), venous invasion (present: 0% vs absent: 54.5%, P = 1.00) or procedure time of endoscopic resection (36.3 ± 8.3 min vs 36.7 ± 9.0 min, P = 0.98) were observed between the patients with and without fluorescence. Fluorescence detection rate tended to be high for elevated lesions. Liver dysfunction developed in 4/10 (40.0%) patients. The extent of the liver dysfunction was a slight increase in transaminases and total bilirubin levels, which spontaneously improved in the patients. None of the patients developed photosensitivity.

CONCLUSION: Results of this preliminary study suggest the utility of PDD using 5-ALA for screening of gastric and colorectal cancers.

Development of a Novel Endoscopic Manipulation System: The Endoscopic Operation Robot ver. 2

BACKGROUND/AIMS

The Endoscopic Operation Robot (EOR) ver. 1 was developed in order to provide robotized operational support for flexible endoscopes, which can be complicated to manipulate. However, total colonoscopy examinations with a colonoscopy training model by proficient operation of the joystick using the EOR ver. 1 took about 6 times longer to reach the cecum than with current manual operation. Thus, EOR ver. 2 is a newly developed robot.

METHODOLOGY

The time required total colonoscopy examinations with a colonoscopy training model was performed compared using the EOR ver. 1 and using the EOR ver. 2.

RESULTS

The median insertion time (in minutes) was 17.20 ± 3.92 in the EOR ver. 1 group and 9.30 ± 2.13 in the EOR ver. 2 group (p < 0.05).

CONCLUSION

The study suggested the possibility of the clinical application Of the EOR.

Efficacy of cap-assisted colonoscopy according to lesion location and endoscopist training level

AIM: To evaluate the efficacy of cap-assisted colonoscopy (CAC) for detection of colorectal polyps and adenomas according to the lesion location and endoscopist training level.

METHODS: Patients 20 years or older, who underwent their first screening colonoscopy in a single tertiary center from May 2011 to December 2012 were enrolled in this study. All patients underwent either CAC or standard colonoscopy (SC), and all of the procedures were performed by 11 endoscopists (8 trainees and 3 experts). All procedures were performed with high-definition colonoscopes and narrow band imaging. The eight trainees had experiences of performing 150 to 500 colonoscopies, and the three experts had experiences of performing more than 3000 colonoscopies. A 4-mm-long transparent cap was attached to the end of a colonoscope in the CAC group. We retrospectively evaluated the number of polyps and adenomas, polyp detection rate (PDR), and the number of adenomas and adenoma detection rate (ADR) according to the lesion location and endoscopist training level between CAC and SC. We also evaluated the number of polyps and adenomas according to their size between CAC and SC.

RESULTS: Overall, PDR and ADR using CAC were significantly higher than those using SC for both whole colon (48.5% vs 40.7%, P = 0.012; 35.7% vs 28.3%, P = 0.012) and right-side colon (35.3% vs 26.6%, P = 0.002; 27.0% vs 16.9%, P < 0.001). The number of polyps and adenomas per patient using CAC was significantly higher than that using SC for both the whole colon (1.07 ± 1.59 vs 0.82 ± 1.31, P = 0.008; 0.72 ± 1.32 vs 0.50 ± 1.01, P = 0.003) and right-side colon (0.66 ± 1.18 vs 0.41 ± 0.83, P < 0.001; 0.46 ± 0.97 vs 0.25 ± 0.67, P < 0.001). In the trainee group, the PDR and ADR using CAC were significantly higher than those using SC for both the whole colon (46.7% vs 39.7%, P = 0.040; 33.9% vs 26.0%, P =0.012) and right-side colon (34.2% vs 26.5%, P = 0.015; 25.3% vs 15.9%, P = 0.001). In the expert group, the PDR and ADR using CAC were significantly higher than those using SC only for the right-side colon (42.1% vs 27.0%, P =0.035; 36.8% vs 21.0%, P = 0.020).

CONCLUSION: CAC is more effective than SC for detection of colorectal polyps and adenomas, especially when performed by trainees and when the lesions are located in the right-side colon.

Clinical impact of endoscopy position detecting unit (UPD-3) for a non-sedated colonoscopy

AIM: To evaluate whether an endoscopy position detecting unit (UPD-3) can improve cecal intubation rates, cecal intubation times and visual analog scale (VAS) pain scores, regardless of the colonoscopist’s level of experience.

METHODS: A total of 260 patients (170 men and 90 women) who underwent a colonoscopy were divided into the UPD-3-guided group or the conventional group (no UPD-3 guidance). Colonoscopies were performed by experts (experience of more than 1000 colonoscopies) or trainees (experience of less than 100 colonoscopies). Cecal intubation rates, cecal intubation times, insertion methods (straight insertion: shortening the colonic fold through the bending technique; roping insertion: right turn shortening technique) and patient discomfort were assessed. Patient discomfort during the endoscope insertion was scored by the VAS that was divided into 6 degrees of pain.

RESULTS: The cecum intubation rates, cecal intubation times, number of cecal intubations that were performed in < 15 min and insertion methods were not significantly different between the conventional group and the UPD-3-guided group. The number of patients who experienced pain during the insertion was markedly less in the UPD-3-guided group than in the conventional group. Univariate and multivariate analysis showed that the following factors were associated with lower VAS pain scores during endoscope insertion: insertion method (straight insertion) and UPD-3 guidance in the trainee group. For the experts group, univariate analysis showed that only the insertion method (straight insertion) was associated with lower VAS pain scores.

CONCLUSION: Although UPD-3 guidance did not shorten intubation times, it resulted in less patient pain during endoscope insertion compared with conventional endoscopy for the procedures performed by trainees.

Endocuff-assisted colonoscopy increases polyp detection rate: a simulated randomized study involving an anatomic colorectal model and 32 international endoscopists

BACKGROUND

The undetected colonic lesions behind the folds and flexures are a major factor contributing to the adenoma miss rate.

OBJECTIVE

To assess the efficacy of Endocuff, a special attachment was fixed at the distal tip of a colonoscope, for the polyp detection. This soft accessory is composed of a plastic cap surrounded by flexible finger-like projections on the lateral sides of the cap that make holding of the folds during scope withdrawal easier.

DESIGN

This was a simulated pilot study with one anatomic colorectal model, containing 13 polyps positioned in obvious locations and behind the folds. Thirty-two endoscopists (16 Japanese and 16 foreign visitors) with different levels of experience performed examinations on the model in a randomized order by using Endocuff-assisted colonoscopy (EAC) and standard colonoscope (SC).

MAIN OUTCOME MEASUREMENTS

To assess the detection rate of polyps and the feasibility of Endocuff insertion.

RESULTS

EAC detected significantly more polyps than SC with 9.9 versus 7.5 mean lesions (p = 0.03), respectively, comparing the 16 first colonoscopies in each group. Endocuff was useful independent of the level of experience of the participants. After crossover, EAC in second position allowed an additional detection of 1.8 polyps compared with SC (p = 0.001). After adjustment on experience, time of detection, and order of colonoscopy, EAC over-detected 1.2 polyps (p = 0.0037). The insertion time (p = 0.99) was identical. There was no difference in the mean time of polyp detection between EAC and SC groups (p = 0.520).

LIMITATIONS

This was not a clinical study. The stiffness of the folds in the colonic model was higher than in the human large bowel.

CONCLUSION

EAC was associated with a higher polyp detection rate. Even in such relatively stiff anatomic model, it was easier to spread out the colonic mucosa between the folds using this cap. This study provides an additional argument for the routine application of this easy-to-use accessory to improve polyp detection.

Evaluation of two flexible colonoscopy simulators and transfer of skills into clinical practice

INTRODUCTION

Surgical residents have learned flexible endoscopy by practicing on patients in hospital settings under the strict guidance of experienced surgeons. Simulation is often used to "pretrain" novices on endoscopic skills before real clinical practice; nonetheless, the optimal method of training remains unknown. The purpose of this study was to compare endoscopic virtual reality and physical model simulators and their respective roles in transferring skills to the clinical environment.

METHODS

At the beginning of a skills development rotation, 27 surgical postgraduate year 1 residents performed a baseline screening colonoscopy on a real patient under faculty supervision. Their performances were scored using the Global Assessment of Gastrointestinal Endoscopic Skills (GAGES). Subsequently, interns completed a 3-week flexible endoscopy curriculum developed at our institution. One-third of the residents were assigned to train with the GI Mentor simulator, one-third trained with the Kyoto simulator, and one-third of the residents trained using both simulators. At the end of their rotations, each postgraduate year 1 resident performed one posttest colonoscopy on a different patient and was again scored using GAGES by an experienced faculty.

RESULTS

A statistically significant improvement in the GAGES total score (p < 0.001) and on each of its subcomponents (p = 0.001) was observed from pretest to posttest for all groups combined. Subgroup analysis indicated that trainees in the GI Mentor or both simulators conditions showed significant improvement from pretest to posttest in terms of GAGES total score (p = 0.017 vs 0.024, respectively). This was not observed for those exclusively using the Kyoto platform (p = 0.072). Nonetheless, no single training condition was shown to be a better training modality when compared to others in terms of total GAGES score or in any of its subcomponents.

CONCLUSION

Colonoscopy simulator training with the GI Mentor platform exclusively or in combination with a physical model simulator improves skill performance in real colonoscopy cases when measured with the GAGES tool.

Measurement system that improves the accuracy of polyp size determined at colonoscopy

AIM: To assess the accuracy of polyp size using an endoscopic lesion measurement system (ELMS).

METHODS: The accuracy of polyp size assessment was compared among measurements acquired by visual estimation, disposable graduated biopsy forceps (DGBF; used as a “scale-plate”) and the ELMS.

RESULTS: There were 192 polyps from 166 cases included in this study. The mean diameter of the post polypectomy measurement was 0.85 ± 0.53 cm (range: 0.2-3.0 cm). The mean diameter by visual estimation was 1.10 ± 0.53 cm, which was significantly different compared to the actual size of the polyp (P < 0.001). The mean diameters obtained using DGBF (0.87 ± 0.54 cm) and ELMS (0.85 ± 0.53 cm) did not significantly differ from the actual size of the polyp. The difference between the measurements from the ELMS and DGBF was not significant.

CONCLUSION: Unlike visual estimations at colonoscopy, endoscopic graduated biopsy forceps and the endoscopic lesion measurement system are accurate methods to estimate polyp size.

Short turn radius colonoscope in an anatomical model: Retroflexed withdrawal and detection of hidden polyps

AIM: To evaluate the new RetroView™ colonoscope and compare its ability to detect simulated polyps “hidden” behind colonic folds with that of a conventional colonoscope, utilizing anatomic colon models.

METHODS: Three anatomic colon models were prepared, with twelve simulated polyps “hidden” behind haustral folds and five placed in easily viewed locations in each model. Five blinded endoscopists examined two colon models in random order with the conventional or RetroView™ colonoscope, utilizing standard withdrawal technique. The third colon model was then examined with the RetroView™ colonoscope withdrawn initially in retroflexion and then in standard withdrawal. Polyp detection rates during standard and retroflexed withdrawal of the conventional and RetroView™ colonoscopes were determined. Polyp detection rates for combined standard and retroflexed withdrawal (combination withdrawal) with the RetroView™ colonoscope were also determined.

RESULTS: For hidden polyps, retroflexed withdrawal using the RetroView™ colonoscope detected more polyps than the conventional colonoscope in standard withdrawal (85% vs 12%, P = 0.0001). For hidden polyps, combination withdrawal with the RetroView™ colonoscope detected more polyps than the conventional colonoscope in standard withdrawal (93% vs 12%, P≤ 0.0001). The RetroView™ colonoscope in “combination withdrawal” was superior to other methods in detecting all (hidden + easily visible) polyps, with successful detection of 80 of 85 polyps (94%) compared to 28 (32%) polyps detected by the conventional colonoscope in standard withdrawal (P < 0.0001) and 67 (79%) polyps detected by the RetroView™ colonoscope in retroflexed withdrawal alone (P < 0.01). Continuous withdrawal of the colonoscope through the colon model while retroflexed was achieved by all endoscopists. In a post-test survey, four out of five colonoscopists reported that manipulation of the colonoscope was easy or very easy.

CONCLUSION: In simulated testing, the RetroView™ colonoscope increased detection of hidden polyps. Combining standard withdrawal with retroflexed withdrawal may become the new paradigm for “complete screening colonoscopy”.