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Background: Endoscopic techniques allow resections of deep submucosal invasion rectal carcinoma, but mostly are facing issues such as costs, follow-up care or size limit. Our aim was to design a new endoscopic technique, which retains the advantages over surgical resections while eliminating the disadvantages mentioned above., Patients and Methods: We propose a technique for the resection of the superficial rectal tumours, with highly suspicious deep submucosal invasion. It combines steps of endoscopic submucosal dissection, muscular resection and edge-to-edge suture of the muscular layers, finally performing the equivalent of a "transanal endoscopic microsurgery" with a flexible colonoscope (F-TEM)., Results: A 60-year-old patient was referred to our unit, following the discovery of a 15 mm distal rectum adenocarcinoma. The computed tomography and the endoscopic ultrasound examination revealed a T1 tumour, without secondary lesions. Considering that the initial endoscopic evaluation highlighted a depressed central part of the lesion, with several avascular zones, an F-TEM was performed, without severe complication. The histopathological examination revealed negative resection margins, without risk factors for lymph node metastasis, no adjuvant therapy being proposed., Conclusion: F-TEM allows endoscopic resection of highly suspicious deep submucosal invasion T1 rectal carcinoma and it proves to be a feasible alternative to surgical resection or other endoscopic treatments as endoscopic submucosal dissection or intermuscular dissection., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Introduction: Practicing endoscopic procedures is fundamental for the education of clinicians and the benefit of patients. Despite a diverse variety of model types, there is no system simulating anatomical restrictions and variations in a flexible and atraumatic way. Our goal was to develop and validate a new modelling approach for adhesion forces between colon and abdominal wall., Methods: An inlay for a standard mechanical trainer was designed and 3D printed. Colon specimens were fixed to the inlay along colon ascendens (CA) and colon descendens (CD) by a vacuum. Our system, which we refer to as Colonoscopy Vacuum Model (CoVaMo), was validated with 11 test persons with varying level of expertise. Each performed one colonoscopy and one polypectomy in the CoVaMo and in the Endoscopic Laparoscopic Interdisciplinary Training Entity (ELITE). Achieved adhesion forces, times required to fulfill different tasks endoscopically and a questionnaire, assessing proximity to reality, were recorded., Results: Mean adhesion forces of 37 ± 7 N at the CA and 30 ± 15 N at the CD were achieved. Test subjects considered CoVaMo more realistic than ELITE concerning endoscope handling and the overall anatomy. Participants needed statistically significantly more time to maneuver from anus to flexura sinistra in CoVaMo (377 s ± 244 s) than in ELITE (58 s ± 49 s)., Conclusion: We developed a training environment enabling anatomically and procedural realistic colonoscopy training requiring participants to handle all endoscope features in parallel. Fixation forces compare to forces needed to tear pig colon off the mesentery. Workflow and inlay can be adapted to any arbitrary ex vivo simulator., (© 2022. The Author(s).)

Background: Adenoma detection rate (ADR) is the single most important measure of quality in colonoscopy, but little is known about the detection rate of serrated lesions (SLDR). To improve ADR, Endocuff Vision (EV) can be used. Studies have shown differing results as to the effect on ADR; an effect on SLDR has not been shown. To investigate the effect of Endocuff Vision on ADR in a screening population, this randomized controlled open label trial with concealed allocation was performed. Randomization to trial group was carried out by the endoscopist using prepared numbered envelopes., Methods: Patients referred as part of the national bowel screening program at Regional Hospital Herning, Denmark were recruited and allocated to one of two groups: Endocuff Vision colonoscopy (EVC) and standard colonoscopy (SC). Outcomes were ADR, mean number, site, and size of lesions per procedure. SLDR as outcome was added after inclusion had begun., Results: A total of 1178 participants were included, with 1166 (EVC 583 and SC 583) available for analysis. There was no clinical relevant difference in ADR (59.2% [CI 55.1; 63.1] v 60.5% [CI 56.5; 64.4]) or SLDR (13.0% [CI 10.5; 16.0] v 10.3% [CI 8.0; 13.0]) between groups. More serrated lesions were found per procedure (MSP) (0.2 v 0.1, IRR 57% [CI 17; 109]. Removal rate of EV was similar in the two study groups., Conclusion: We found no significant effects of the use of Endocuff Vision on ADR, when compared to standard colonoscopy, but more serrated lesions were detected in the Endocuff group., Trial Registration: Clinical Trials NCT04651062., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

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., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Colonoscopy is a technically challenging procedure. The colonoscope is prone to forming loops in the colon, which can lead patient discomfort and even perforation. We hypothesized that expert endoscopists use techniques to avoid loop formation, identify and straighten loops earlier, and thus exert less force., Methods: Using a commercially available physical colon simulator model (Kyoto Kagaku), electromagnetic tracking markers (NDI Medical) were placed along the mobile segments of the colon (sigmoid, transverse) to measure the degree of displacement of the colon as the scope was advanced to the cecum. The colon model was set for each participant to simulate a redundant alpha loop in the sigmoid colon. Gastroenterology and surgical trainees and attendings were assessed. Demographic data were collected for each participant., Results: Seventy-five participants were enrolled in the study. There were 17 (22.7%) attending physicians, and 58 (77.3%) trainees. Attending physicians advanced the scope to the cecum faster. The mean time required for procedure completion was 360.5 s compared to 178.4 s for the trainee and attending groups respectively (mean difference: 182.1 s, 95% CI: 93.0, 269.7; p = 0.0002). Attending physicians exerted significantly lower mean colonic displacement than trainees. The mean colonic displacement was 79.8 mm for the trainee group and 57.9 mm for the attending group (mean difference: 21.9 mm, 95% CI: 2.6, 41.2; p = 0.04). Those who used torque steering caused lower maximum colonic displacement than those who used knob steering., Conclusion: Attending physicians advance the scope during colonoscopy in a manner that results in significantly less colonic displacement than resident trainees. Although prior studies have shown a difference in force application between endoscopists and inexperienced students, ours is the first to differentiate across varying degrees of endoscopic skill. Future studies will define metrics for incorporation into endoscopic training curricula, focusing on techniques that encourage safety and comfort for patients., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: 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., Methods: 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., Results: 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 < 0.001), with low evidence of between-study heterogeneity (I 2  = 0%). Although the total PDR was slightly higher with dynamic position changes than with a static position (OR 1.23; 95% CI 0.88-1.73), there difference was not statistically significant (p = 0.22). The withdrawal time was only increased by 0.47 min (95% CI - 0.11 to 1.06) with dynamic position changes, without statistical significance (p = 0.11). The subgroup analysis showed that the ADR and PDR for the transverse colon were higher with dynamic position changes, with pooled estimates of ADR (OR 1.72; 95% CI 1.02-2.88; p = 0.04) and PDR (OR 1.79; 95% CI 1.08-2.96; p = 0.02)., Conclusion: Dynamic position changes during colonoscope withdrawal increased the total ADR; however, no obvious increase was found in the total PDR. The withdrawal time was not significantly prolonged with dynamic position changes. Subgroup analysis showed that the ADR and PDR in the transverse colon were obviously improved with dynamic position changes.

Background: Missed adenomas are the main concern for endoscopists. Right colon retroflexion (RCR) seems to increase the adenoma detection rate (ADR), but important variation in success and usefulness of this maneuver has been reported in the literature AIMS: Primary objective: to assess additional adenoma detection rate (AADR) detected during the RCR attempt. Secondary objectives: to assess success rates of RCR, variables associated with it, and safety of RCR., Methods: This is a prospective, unicentric, non-randomized study. Consecutive colonoscopies done by six endoscopists (3 of them with < 3 years of experience and 3 with > 3 years) from March to May 2017 were included. Olympus colonoscopes were used (CF-H190, CF-H180) Demographic, clinical, and endoscopic variables were collected., Results: 463 colonoscopies were included. RCR success rate was 93.1% (431/463 colonoscopies). Forty additional lesions were visualized during RCR in 34/463 colonoscopies (7.3%). Additional adenomas were detected in 31/463 colonoscopies (6.7%; OR 0.07)., Histology: low-grade dysplasia adenomas in 29/40 (72.5%) lesions; 3/40 (7.5%), adenomas with high-grade dysplasia; and 7/40 (17.5%) sessile serrated lesions. Additional adenoma detection contributed to modify the colonoscopy surveillance interval in 25 patients (5.4% of the cohort). Variables associated with RCR success in multivariate analysis were no previous abdominal surgery, length of colonoscope insertion in cecum < 80 cm, and use of Olympus 190 series colonoscopes. No differences between endoscopists' experience were found. RCR was a safe maneuver, with no adverse events in our study., Conclusions: RCR is a feasible and safe maneuver that can increase ADR, so its routine inclusion in colonoscopy practice should be considered.

Background and Goals: 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., Study: 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., Results: 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)., Conclusions: 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.

Background: 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., Methods: 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., Results: 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)., Conclusion: 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.

Background: At present, the colonoscopy is the most common method of screening for colorectal cancer. However, endoscopists still encounter difficulties with intubation, primarily due to the structural diversity (e.g., path, shape, and size) and viscoelasticity of the colon. Therefore, well-trained, skillful operators are required to overcome these factors and operate colonoscopes without harming patients., Objectives: In our previous work, we presented a reel mechanism-based robotic colonoscope designed to mitigate the difficulties of conventional colonoscopies. Although we reported excellent mobile performance with respect to the robot, we did not provide an in-depth discussion concerning patient safety. Therefore, in this article, we propose a method of improving robot safety, and this is verified by investigating the static and dynamic forces acting on the colon. In addition, the maneuverability and safety of the robot in the in vitro condition are evaluated., Methods: The safety solution is provided by covering the robot's legs with silicone. To evaluate the results, the reaction force according to leg deformation is measured. Then, the force transmitted to the colon is also measured when the robot moves through various environments. Finally, a mobility test on an excised porcine colon is performed to simultaneously verify the robot's maneuverability and safety., Results: We verify that the static and dynamic force acting on the colon is less than the burst force of a human colon. In addition, the maneuverability of the robotic colonoscope shows reliable locomotion performance even with the soft material covering the legs; it has forward velocities of 9.552 ± 1.940 mm/s on a flat path., Conclusion: Owing to the reliable locomotion mechanism with the safety-securing silicone, the robot achieves high and reliable maneuverability without any scratches or perforations to the porcine colon.

Objective: Manipulation of the colonoscope is a technical challenge for novice clinicians which is best learned in a simulated environment. It involves the coordination of scope tip steering with scope insertion, using a rotated image as reference. The purpose of this work is to develop and validate a system which objectively assesses colonoscopy technical skills proficiency in an arbitrary training environment, allowing novices to assess their technical proficiency prior to real patient encounters., Methods: We implemented a motion tracking setup to objectively analyze and assess the way operators perform colonoscopies, including an analysis of wrist and elbow joint motions. Subsequently, we conducted a validation study to verify whether our motion analysis could discriminate novice colonoscopists from experts. Participants navigated a wooden bench-top model using a standard colonoscope while their motions were tracked., Results: The developed motion tracking setup allowed colonoscopists of varying levels of proficiency to have their colonoscope manipulation assessed, and was able to be operated by a trained non-technical operator. Novice operators had significantly greater median times (101.5 vs. 31.5 s) and number of hand movements (62.0 vs. 21.5) than experts. Experts, however, spent a significantly greater proportion of time in extreme ranges of wrist and elbow joint motion than novices., Conclusion: We have developed and implemented a hand and joint motion analysis system that is able to discriminate novices from experts based on objective measures of motion. These metrics could, thus, serve as proxies for technical proficiency during training.

Background: Effective control of the colonoscope tip is one of the most fundamental components of colonoscopy skill. Mastering fine tip control can be problematic for novice trainees, yet no validated training regimes exist for developing this specific skill component in isolation. We aimed to conduct a preliminary validation of a novel training device for colonoscopic tip control, and to assess its efficacy as a training tool., Methods: In study 1 (validation), 13 experienced colonoscopists and 16 novices used a colonoscope to accurately track 28 targets on each of four concave "training surfaces" as quickly as possible, and we compared their performance. In study 2 (pre-post-training study), another 16 novices were tested before and after a six-session training program. In both studies, the main outcome measurements were completion time (measured automatically by the device) and variability of individual performance (the SD of each individual's completion times across trials)., Results: Compared with novices, experienced colonoscopists were faster (P < 0.0001) and their performances less variable (P < 0.0001). With training, novices became faster (P < 0.0001) and more consistent (P = 0.003), and these improvements also generalized to novel training surfaces (P's < 0.01). After training, the novices' tip control performance was indistinguishable from that of the experienced colonoscopists (P's > 0.05). The composite measures of completion time used in both studies all had acceptable to excellent internal consistency reliability (α's ranged from 0.72 to 0.93)., Conclusions: We found that performance measures derived from using the device to assess skill can discriminate between experienced colonoscopists and novices in terms of their ability to control and guide the colonoscope tip precisely, providing preliminary evidence to support the construct validity of the metrics. The device is also an effective training tool for this fundamental component of colonoscopy skill.

Background: Ultrathin colonoscopes (UTC) reportedly produce less pain during colonoscopy than standard colonoscopes. The aim of this study was to assess the tolerability of an UTC compared with that of a pediatric colonoscope., Methods: A total of 270 adult patients scheduled to undergo colonoscopy were randomized, with 134 allocated to the UTC group and 136 to the pediatric colonoscope group. Pain was assessed using a visual analog scale. For all procedures, sedation was administered only if requested. Overall pain, rate and time of cecal and terminal ileum intubation, number of patients requesting sedation, adenoma detection rates (ADR), and rate of complications were measured and analyzed., Results: Among all patients, the medians of maximum pain and overall pain were significantly lower in the UTC group than in the pediatric colonoscope group (23 vs. 38, P < 0.001; 12 vs. 22, P = 0.0003, respectively). Significantly fewer patients requested sedation in the UTC group than in the pediatric colonoscope group (1.4 vs. 6.6%; P = 0.0269). No significant differences were seen in either the rate and time of successful cecal and terminal ileum intubation, or in other procedure-related outcomes, including ADR., Conclusions: Compared with a pediatric colonoscope, the UTC was associated with reduced overall and maximum pain during colonoscopy, with no difference in ADR.

Purpose: Polyps found during CT colonography can be removed by colonoscopic polypectomy. A colonoscope navigation system that navigates a physician to polyp positions while performing the colonoscopic polypectomy is required. Colonoscope tracking methods are essential for implementing colonoscope navigation systems. Previous colonoscope tracking methods have failed when the colon deforms during colonoscope insertions. This paper proposes a colonoscope tracking method that is robust against colon deformations., Method: The proposed method generates a colon centerline from a CT volume and a curved line representing the colonoscope shape (colonoscope line) by using electromagnetic sensors. We find correspondences between points on a deformed colon centerline and colonoscope line by a landmark-based coarse correspondence finding and a length-based fine correspondence finding processes. Even if the coarse correspondence finding process fails to find some correspondences, which occurs with colon deformations, the fine correspondence finding process is able to find correct correspondences by using previously recorded line lengths., Result: Experimental results using a colon phantom showed that the proposed method finds the colonoscope tip position with tracking errors smaller than 50 mm in most trials. A physician who specializes in gastroenterology commented that tracking errors smaller than 50 mm are acceptable. This is because polyps are observable from the colonoscope camera when positions of the colonoscope tip and polyps are closer than 50 mm., Conclusions: We developed a colonoscope tracking method that is robust against deformations of the colon. Because the process was designed to consider colon deformations, the proposed method can track the colonoscope tip position even if the colon deforms.

Background: Conventional colonoscopy requires a high degree of operator skill and is often painful for the patient. We present a preliminary feasibility study of an alternative approach where a self-propelled colonoscope is hydraulically driven through the colon., Methods: A hydraulic colonoscope which could be controlled manually or automatically was developed and assessed in a test bed modelled on the anatomy of the human colon. A conventional colonoscope was used by an experienced colonoscopist in the same test bed for comparison. Pressures and forces on the colon were measured during the test., Results: The hydraulic colonoscope was able to successfully advance through the test bed in a comparable time to the conventional colonoscope. The hydraulic colonoscope reduces measured loads on artificial mesenteries, but increases intraluminal pressure compared to the colonoscope. Both manual and automatically controlled modes were able to successfully advance the hydraulic colonoscope through the colon. However, the automatic controller mode required lower pressures than manual control, but took longer to reach the caecum., Conclusions: The hydraulic colonoscope appears to be a viable device for further development as forces and pressures observed during use are comparable to those used in current clinical practice., Competing Interests: Compliance with ethical standards Disclosures Mr. Stuart A. Coleman, Dr. Silvia C. Tapia-Siles, Mr. Markus Pakleppa, Dr. Jan B. Vorstius, Professor Robert P. Keatch, Dr. Benjie Tang and Professor Alfred Cuschieri have no conflicts of interest or financial ties to disclose.

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.

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.

With hereditary colorectal cancer prevention studies it is difficult to demonstrate reduced mortality. Large populations are needed with well characterized genetics followed over a long period of time. Those studies do exist for standard white light colonoscopy surveillance in Lynch syndrome, but not for newer technologies including chromoscopy. For these newer technologies adenoma detection rate becomes the stand-in for mortality, and the assumption is made that surveillance efficacy impacts cancer occurrence. Though well-designed and important work exists in this area, the data do not support firm conclusions regarding the use of chromoscopy in Lynch syndrome.

Background: The rate of cecal intubation is a well-recognized quality measure of successful colonoscopy. Infrequently, the standard colonoscopy techniques fail to achieve complete examination. The role of single-balloon overtube-assisted colonoscopy (SBC) in these situations has only been sparsely studied. This prospective single-center study aimed to investigate the technical success (rate of cecal intubation) and the diagnostic gain of SBC., Methods: The study recruited consecutive patients with previous incomplete standard colonoscopy who were admitted for SBC at our tertiary center in Eastern Switzerland between February 2008 and October 2014. The primary outcome was defined as successful cecal intubation. Data on patient characteristics, indication, technical details of procedure, and outcome were collected prospectively. The Olympus enteroscope SIF-Q180 was used., Results: The study included 100 consecutive patients (median age 70 years; range 38-87 years; 54 % female) who were examined using a single-balloon overtube-assisted technique. The cecal intubation rate was 98 % (98/100). The median time of total procedure was 54 min (range 15-119 min); the median time to reach the cecal pole was 27.5 min (range 4-92 min). Passage of the sigmoid colon was not possible in two cases with a fixed, angulated sigmoid colon. The diagnostic gain was 21 % regarding adenomatous polyps in the right colon. The complication rate was 2 % (2/100, minor) without need for surgery., Conclusions: This prospective patient cohort study shows that single-balloon colonoscopy is a safe and effective procedure to achieve a complete endoscopic examination in patients with a previous failed standard colonoscopy. A significant diagnostic and therapeutic gain in the right colon justifies additional procedure time.

Background and Aims: Macroscopic real-time evaluations of the histopathology and degree of invasion of colorectal polyps help to select the most suitable endoscopic treatment method. Dual-focus (DF) narrow-band imaging (NBI) is a new imaging enhancement system that uses digital and optical methods to enhance the view of blood vessels on mucosal surfaces. However, the superiority of this technique over standard imaging techniques has not been previously reported. The aim of this study was to determine whether the two-stage optical systems in a new generation of endoscopes will increase the diagnostic accuracy of colorectal polyp recognition., Methods: The study included 270 patients, and 386 colorectal polyps were diagnosed and removed. The polyps were assessed with white light and NBI using one- and two-stage optical systems, respectively. After being classified according to the Kudo pit pattern schemes, the polyps were removed and histopathologically verified., Results: Regarding non-neoplastic lesions (Kudo I and II), no difference was observed in the recognition of polyps when using the NBI-DF function. We observed improved accuracy in the preliminary diagnoses of Kudo IIIL lesions (from 87.16 to 90.09%, p < 0.05) and Kudo IIIS lesions (from 87.29 to 92.79%, p < 0.01). NBI-DF also increased the accuracy of preliminary diagnoses of Kudo IV lesions (from 88.24 to 94.12%, p < 0.01). The Kudo V pit patterns were also more distinct with NBI-DF imaging, increasing the diagnostic accuracy from 91.67 to 100%., Conclusions: Using a two-stage optical system with electronic colorization of the mucosa increased diagnostic accuracy for differentiating colorectal polyps with neoplastic potential.

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.

Background: Colonoscopy is considered the most effective method for diagnosing colorectal diseases, but its application is sometimes limited due to invasiveness, patient intolerance, and the need for sedation., Objective: The aim of this study was to improve the problem of loop formation and shorten the cecal intubation time of colonoscopy by using a magnetic control system (MCS)., Methods: Two experienced gastroenterologists, three trainees, and a novice repeated colonoscopy without or with MCS on three colonoscopy training model simulator cases. These cases were divided into introductory (case 2) and challenging levels (cases 4 and 5). The cecal intubation times were recorded., Results: For all cases, the average cecal intubation times for the experienced gastroenterologists with MCS were significantly shorter than without MCS (case 2: 52.45 vs. 27.65 s, p < 0.001; case 4: 166.7 vs. 120.55 s, p < 0.01; case 5: 130.35 vs. 100.2 s, p < 0.05). Those of the trainees also revealed significantly shorter times with MCS (case 2: 67.27 vs. 51 s, p < 0.01; case 4: 253.27 vs. 170.97 s, p < 0.001; case 5: 144.1 vs. 85.57 s, p < 0.001)., Conclusion: Conducting colonoscopy with MCS is safe and smooth, and shortens the cecal intubation time by navigating the forepart of the colonoscope. In addition, all diagnostic and therapeutic benefits of conventional colonoscopy are retained.

Background: There is more to a high-quality colonoscopy than reaching the cecum or finding adenomas. Gentle insertion involves ancillary techniques, some of which are impossible in patients receiving deep sedation. The aim of this study was to assess the importance of ancillary techniques in achieving a comfortable, complete colonoscopy., Methods: This was a prospective study of 500 consecutive outpatient colonoscopies performed by a single endoscopist. During the procedure, note was taken of various ancillary techniques used to facilitate insertion: turning the patient, patient holding their breath, abdominal pressure. The success of these techniques in helping scope advancement was also noted. After the procedure the patient was asked to rate the severity of their pain and their degree of satisfaction with the examination., Results: A total of 238 women and 262 men participated in the study, and colonoscopy was complete in 96.2 and 98.5%, respectively. Overall, 97% of patients received versed alone (average dose 2 mg), and 3% received a narcotic (average dose 46 U). Average pain score was 3.9 on a scale of 1 (least pain) to 10 (worst pain), and average satisfaction with the procedure as a whole was 9.5 on a similar scale. Ancillary techniques of holding breath, directed abdominal pressure, and turning to the left, right, and prone were used in 46, 56, 17, 23, and 4% of examinations, respectively. Each technique was effective in helping insertion in over 70% of cases. Turning the patient was also used to clear stool, open the colon, or facilitate polypectomy in another 33 cases. Multiple techniques were used in 49% of patients., Conclusion: The use of ancillary techniques to facilitate colonoscope insertion helps avoid the expense and potential side effects of deep sedation.

A new concept of endoscopic device based on a compact optical probe which can capture 3D shape of objects using an active stereovision method is presented. The distinctive feature of this probe is its capability to dynamically switch between two distinct points of view. If the first measurement angle of view does not give results with sufficient quality, the system can switch to a second mode which sets distinct angle of view within less than 25 milliseconds. This feature consequently allows selecting the angle that provides the more useful 3D information and enhances the quality of the captured result. The instrumental setup of this measurement system and the reconstruction algorithms are presented in this paper. Then, the advantages of this new endoscopic probe are explained with an experimental 3D reconstruction of a coin's surface. Finally, first measurements on a phantom colon are provided. In future works, further miniaturization of the device and its integration into a real colonoscope will be implemented.

Background: We evaluated the performance of a newly developed small-caliber (SC) colonoscope (PCF-PQ260L). This colonoscope (diameter 9.2 mm) is designed with passive-bending and high-force transmission. The SC colonoscope was used for rescue colonoscopy following incomplete colonoscopy with a standard (SD) colonoscope caused by sharp angulation, loop formation, or pain., Methods: Records of SC colonoscopy given to patients following an incomplete colonoscopy with the SD colonoscope and in the same session were analyzed. Cecal intubation rate, pain using a visual analog scale (0 = none, 100 = extremely painful) in the first and second colonoscopy, total time, new lesions detected with the SC colonoscopy, dosage of sedation used, and any complications were assessed. Examinations that could not be completed, because the colonoscope was not long enough to reach the cecum due to a redundant colon were excluded., Results: The records of 43 patients who were given SC colonoscopy following incomplete examinations using the SD colonoscope were reviewed. In 97.7 % of cases (42/43), cecal intubation was achieved with the SC colonoscope in the same session. The mean pain score during colonoscopy was significantly lower for the second SC colonoscopy than for the first SD colonoscopy (40.6 ± 14.1 vs. 74.5 ± 10.8, P < 0.001). Lesions were detected with the SC colonoscope in 41.8 % of cases (18/43)., Conclusions: When a colonoscopy with SD colonoscope failed due to sharp angulations, loop formation, or pain, subsequent colonoscopy with a SC colonoscope increased cecal intubation and lesion detection rates and decreased severity of reported pain.

Purpose: This review summarizes the published methods of colonic EFTR, examining data on feasibility and safety. Due to the introduction of bowel cancer screening programs, there is an increasing incidence of complex colonic polyps and early colonic cancer that requires segmental colectomy. Traditional radical surgery is associated with significant morbidity, and there is a need for alternative treatments., Methods: Systematic literature search identified articles describing EFTR techniques of colon, published between 1990 and 2012. Complication rates, anastomotic bursting pressures, procedure duration, specimen size and quality, and postmortem findings were analyzed., Results: Five research groups reported four EFTR techniques using endoscopic stapling devices, T-tags, compression closure, or laparoscopic assistance for defect closure before or after specimen resection. A total of 113 procedures were performed in 99 porcine models, with an overall success rate of 89 and 4 % mortality. The intraoperative complication rate was 22 % (0-67 %). Post-resection closure methods more commonly resulted in failure to close the defect (5-55 %) and a high incidence of abnormal findings at postmortem examination (84 %). Significant heterogeneity was observed in procedure duration (median or mean 3-233 min) and size of the excised specimen (median or mean 1.7-3.6 cm). Anastomotic bursting pressures and specimen quality were poorly documented., Conclusions: The technique of EFTR is developing, but the inability to close the resection defect reliably is a major obstacle. The review highlights the challenges that need to be addressed in future preclinical studies.

Background: Transanal endoscopic microsurgical (TEM) resection is associated with improved outcomes compared to transanal excision of rectal lesions. However, TEM equipment requires additional operative setup time, and tumor location dictates patient positioning. In 2010, Drs. Attallah, Albert, and Larach developed an alternative technique, transanal minimally invasive surgery (TAMIS). Herein, we describe our novel experience using endoscopic visualization to perform TAMIS (eTAMIS) to remove a large rectal polyp., Methods: This is a technical note describing a new surgical technique, eTAMIS. The technique is performed with the Gelpoint Path TAMIS platform (Applied Medical, Rancho Santa Margarita, CA) and a standard single-channel endoscope for visualization. Patient demographics, operative data, and pathologic data were recorded., Results: eTAMIS was initially performed in a 50-year-old woman with an endoscopically defiant rectal mass discovered on routine screening colonoscopy. The lesion was a tubulovillous adenoma, 10 cm from the anal verge, anterior, and occupied 15-20 % of the circumference. The rectal mass was removed by eTAMIS. The operative time was 101 minutes, and the patient was discharged within 24 h without event. Final pathology revealed a focus of well-differentiated rectal adenocarcinoma with focal invasion into the muscularis mucosa (Haggit level 0, pTis) arising in the head of a pedunculated tubulovillous adenoma. At 1-year follow-up endoscopy, the patient had no evidence of recurrent mass or polyp., Conclusions: This is the first technical report describing endoscopic visualization for TAMIS. Endoscopic visualization facilitates intraluminal articulation and lens cleaning while minimizing extraluminal instrument collisions. eTAMIS is a practical and logical evolution of the visual approach to natural orifice transluminal endoscopic surgery and laparoendoscopic surgery.

Background: Despite being considered the most effective method for colorectal cancer diagnosis, colonoscopy take-up as a mass-screening procedure is limited mainly due to invasiveness, patient discomfort, fear of pain, and the need for sedation. In an effort to mitigate some of the disadvantages associated with colonoscopy, this work provides a preliminary assessment of a novel endoscopic device consisting in a softly tethered capsule for painless colonoscopy under robotic magnetic steering., Methods: The proposed platform consists of the endoscopic device, a robotic unit, and a control box. In contrast to the traditional insertion method (i.e., pushing from behind), a "front-wheel" propulsion approach is proposed. A compliant tether connecting the device to an external box is used to provide insufflation, passing a flexible operative tool, enabling lens cleaning, and operating the vision module. To assess the diagnostic and treatment ability of the platform, 12 users were asked to find and remove artificially implanted beads as polyp surrogates in an ex vivo model. In vivo testing consisted of a qualitative study of the platform in pigs, focusing on active locomotion, diagnostic and therapeutic capabilities, safety, and usability., Results: The mean percentage of beads identified by each user during ex vivo trials was 85 ± 11%. All the identified beads were removed successfully using the polypectomy loop. The mean completion time for accomplishing the entire procedure was 678 ± 179 s. No immediate mucosal damage, acute complications such as perforation, or delayed adverse consequences were observed following application of the proposed method in vivo., Conclusions: Use of the proposed platform in ex vivo and preliminary animal studies indicates that it is safe and operates effectively in a manner similar to a standard colonoscope. These studies served to demonstrate the platform's added advantages of reduced size, front-wheel drive strategy, and robotic control over locomotion and orientation.

Background: The attachment of a transparent hood to the colonoscope tip has been reported to offer some benefits, such as enabling the endoscopist to perform the colonoscopy more easily and to save time. However, there have been no randomized, controlled trials concerning these benefits, nor have any reports been published regarding the use of hoods for the purpose of training colonoscopists. Therefore, we conducted this study to evaluate the possible benefits of the transparent soft short hood when used by both experienced and trainee endoscopist groups., Methods: This randomized, controlled trial to assess the results of using a transparent soft short hood attached to the tip of the colonoscope was undertaken by two groups of investigators: experienced endoscopists and gastroenterologist trainees. The cecal and ileal intubation times, as well as the doses of sedative medication required, were analyzed., Results: A total of 112 patients, 65 of whom were female, underwent colonoscopy by 2 endoscopists and 5 gastroenterologist trainees. Colonoscopy was complete in 100% of the patients. The study showed significant shortening of the cecal intubation time when using the soft short hood, in both the endoscopist and gastroenterologist trainee groups (6.8/4.61 min, P = 0.006; and 9.36/7.36 min, P = 0.03). The ileal intubation time had a trend to be significantly less when using the transparent hood in the trainee group (126.4/52.9 s), although this was not statistically significant (P = 0.08). The average dose of propofol, when using the transparent hood, was significantly lower in the endoscopist group (180/120 mg, P = 0.001). No significant complications occurred in the hood or non-hood groups., Conclusions: The transparent soft short hood shortened the cecal intubation time in both the experienced endoscopist and gastroenterologist trainee groups, as well as reducing the dose of sedative medication required in the experienced endoscopist group. Interestingly, it also reduced the trainee ileal intubation time. The attachment of this type of hood enabled both the experienced endoscopists and gastroenterological trainees to perform colonoscopy more quickly and easily, without any complications.

Background: Colorectal cancer is the most common cancer in Europe. Early diagnosis and treatment gives the patient a chance for complete recovery. Screening colonoscopies in the symptom-free patients are currently performed on a wide scale. The examinations are performed under local anesthesia which does not eliminate all discomfort and pain related to the examination. The aim of this study was to evaluate magnetic scope navigation in screening endoscopic examinations performed to detect early-stage colorectal cancer., Methods: The study group consisted of 200 patients, aged 40-65 years, who were free from colon cancer symptoms. All patients underwent complete colonoscopy under local anesthesia. The equipment could be fitted with the scope that allows three-dimensional observation of instrument localization in the bowel. The examination was performed by three experienced endoscopists, each of whom performed over 5,000 colonoscopies. The patients were randomized to two groups: those whose equipment did not have 3D navigation (group I) and those whose equipment did have 3D navigation (group II). Each group consisted of 100 cases matched by gender, age, and BMI. The authors compared the duration of introducing instrument to cecum, the pulse rate before the examination and at the time the instrument reached the cecum, and subjective pain evaluation by the patient on the visual analog scale., Results: Group I consisted of 54 women and 46 men with a mean age of 54.6 years and mean BMI of 27.8 kg/m(2), and group II had 58 women and 42 men, mean age of 55.1 years and mean BMI of 26.4 kg/m(2). The average time it took for the instrument to reach the cecum was 216s in group I and 181s in group II (P < 0.05). Pain measured on the 10-point VAS scale was 2.44 in group I and 1.85 in group II (P < 0.05). The results showed a significantly shorter time for the instrument to reach the cecum in group II and significantly lower pain intensity during the examination was reported by the group II patients. No significant differences were found in the pulse measurements between the groups (P = 0.5)., Conclusions: 3D navigation during colonoscopy decreases the time for the instrument to reach the cecum and lowers pain intensity subjectively reported by the patients. The use of 3D and the possibility to observe instrument localization and maneuvers brings more comfort to the patients.

Background: Knowledge of the position and shape of the endoscope could overcome many challenges of performing colonoscopy, e.g., loop formation. A novel computer-assisted colonoscope (NeoGuide Endoscopy System) delivers a real-time, three-dimensional map of the tip position and insertion tube shape in addition to the video image of the colon lumen. The aim of this study is to evaluate the mapping capabilities of the NeoGuide Endoscopy System in terms of colonic looping, insertion depth, tip position, and tip angle formation., Methods: Ten endoscopists with various levels of experience were each shown 70 map images generated by the NeoGuide endoscopy system in a benchtop anatomical colon model. First endoscopists were asked to determine the tip angle based on the map image and the system's corresponding tip positioning aid (20 images). In the second part they had to identify the scope-tip position in the colon model (40 images). In the third part ten images were presented for identification of colonic loops., Results: The tip angle was correctly identified in 99% (198/200) of images. Using only the map images the scope position was accurately determined in 87.5% (350/400). Identification of colonic looping of the scope was appropriate in 99% (99/100). Overall accuracy was 92.4%, and overall positive predictive value was 94.9%., Conclusion: Three-dimensional map images generated by the NeoGuide endoscopy system provide accurate information regarding tip position, insertion tube position, and colonic looping.

Background: The continued success of natural orifice translumenal endoscopic procedures requires reliable, accurate tissue dissection and suture cutting. This study aimed to evaluate a flexible endoscopic scissors prototype., Methods: An acute study of two domestic swine was conducted. Laparoscopic access provided an overview and allowed comparison of the flexible endoscopic scissors with laparoscopic shears. The endoscopic cautery-compatible scissors consists of cutting blades with a flexible wire catheter assembly (outer diameter, 3.1 mm) for use within a therapeutic endoscopic channel. A dual-channel colonoscope was advanced through a gastrotomy created for peritoneal access. With the aide of a grasping forceps, multiple peritoneal biopsies were obtained using the endoscopic scissors. Cautery (Monopolar 18-30 W) then was attached to the scissors, and gallbladder dissection proceeded. The device then was used to perform a small bowel enterotomy. A timed comparison of this function with laparoscopic enterotomy was made. Finally, 3-0 Polyglactin 910 suture was cut using the endoscopic scissors., Results: Peritoneal biopsies 2 cm(2) in size were obtained from multiple abdominal locations and endoscopic positions, including the retroflexed position. The scissors cut effectively and accurately. Cutting performance was enhanced with parallel countertraction provided by grasping forceps passed through the second endoscopic channel. The use of cautery with the scissors controlled small vessels (2-3 mm) and permitted partial dissection of the gallbladder from the hepatic bed. Small bowel enterotomy sufficiently large for stapler passage was created in 4 min and 54 s. Laparoscopically, this was completed in 1 min and 22 s. Suture was successfully cut at the first attempt in a controlled, reproducible fashion., Conclusions: Controlled tissue biopsy, dissection, enterotomy creation, and suture cutting can be performed with this endoscopic scissors. Endoscopic tissue dissection and enterotomy creation was completed effectively but less efficiently than with laparoscopy primarily due to parallel device use imposed by the dual-channel endoscope.

Purpose: Fibre optic colonoscopy is usually performed with manual introduction and advancement of the endoscope, but there is potential for a robot capable of locomoting autonomously from the rectum to the caecum. A prototype robot was designed and tested., Methods: The robot colonic endoscope consists in a front body with clockwise helical fin and a rear body with anticlockwise one, both connected via a DC motor. Input voltage is adjusted automatically by the robot, through the use of reinforcement learning, determining speed and direction (forward or backward)., Results: Experiments were performed both in-vitro and in-vivo, showing the feasibility of the robot. The device is capable of moving in a slippery environment, and reinforcement learning algorithms such as Q-learning and SARSA can obtain better results than simply applying full tension to the robot., Conclusions: This self-propelled robotic endoscope has potential as an alternative to current fibre optic colonoscopy examination methods, especially with the addition of new sensors under development.

Background: Clinical applications of transvaginal Natural Orifice Transluminal Endoscopic Surgery (NOTES) are still limited in the literature, mostly case reports performed by hybrid procedures with laparoscopic assistance. Avoiding complications from incisions is the main goal for natural orifice surgery. This study reports on a technique developed at our institution that uses two endoscopes inserted into the vagina to perform a Totally NOTES (T-NOTES) transvaginal cholecystectomy, and describes preliminary results., Methods: IRB approval was obtained at the institution for transvaginal NOTES clinical trials, and informed consent was obtained. The technique of T-NOTES transvaginal cholecystectomy was clinically applied in four female patients with symptomatic cholelithiasis, and data were prospectively documented. Transvaginal NOTES access was obtained by direct vaginal incision, and two endoscopes were simultaneously introduced in the abdominal cavity. Dissection was accomplished with available endoscopic instruments. Ligation of cystic duct and artery was performed using endoscopic clips. Vaginal closure was achieved using the direct-vision sutured technique., Results: The technique was successfully performed in the four patients. Insufflation and spatial orientation was of good quality. Mean operative time was 210 min. There were no complications during the 30-day follow-up. Postoperative course was uneventful, and patients were released from the hospital on the first postoperative day., Conclusion: Tranvaginal T-NOTES using two endoscopes provides a feasible method for natural orifice cholecystectomy using available technology. Large-series studies are needed to evaluate the results with respect to safety of the approach.

Background: Bleeding after pancreaticoduodenectomy most often occurs from the gastro- or duodeno-jejunal anastomosis. Bleeding at the pancreatic surface would be the most difficult to treat because it typically requires surgical resection of the pancreatic remnant-a surgery that has significant morbidity and mortality. Data that describe the role of endoscopy in the management of pancreaticojejunostomy bleeding are limited., Case: We present the case of a 69-year-old man who had massive upper gastrointestinal bleeding on postoperative day 2 after a pyloric sparing Whipple procedure for cholangiocarcinoma. We endoscopically approached this massive upper gastrointestinal bleed by understanding the postsurgical anatomy to consider all of the potential bleeding sources: duodenojejunostomy, hepaticojejunstomy, and the pancreaticojejunostomy. Using a pediatric colonoscope with water jet capabilities, active bleeding could be seen originating from the cut pancreatic surface. Complete hemostasis was achieved after placement of two clips. We clipped again two clays later due to a minor rebleeding episode. We repeated endoscopy on postoperative day 6 for surveillance of the site. All clips were in place and there was no evidence of bleeding. The patient did well without recurrent bleeding and was discharged home on postoperative day 7. Six-month follow-up showed no recurrent bleeding episodes or development of fistulas., Conclusion: Endoscopic treatment of a bleeding site on the pancreatic surface of a pancreaticojejunostomy can be successful during the immediate postoperative period. Such an attempt at endoscopic hemostasis may prevent the need for completion pancreatectomy.

Background: This study aimed to investigate the effects of magnetic endoscope imaging (MEI) regarding examination time, caecal intubation rate, and sedation and analgesic requirements during routine colonoscopy compared with earlier used X-ray imaging., Methods: Consecutive outpatients undergoing colonoscopy were prospectively studied for two periods. In the first period X-ray was used to establish the correct position of the endoscope. In the second period MEI was used. Outcome measures were examination time, caecal intubation rate, median dose of analgesic and sedative administered, and median X-ray dose used., Results: The two groups studied were comparable with regards to age, sex, and number of therapeutic examinations. The examination time was significantly shorter with use of MEI (median 29 min versus 43 min). No significant differences in the use of analgesic and sedative were found (median 50 microg phentanyle and 2 mg midazolam in both groups). Median X-ray dose was 150 cGy in the group using X-ray imaging., Conclusion: MEI is the imaging methodology of choice and should always be available in colonoscopy, especially for precise locating of colonic lesions.

Background: Stent placement in the distal duodenum or proximal jejunum with a therapeutic gastroscope can be difficult, because of the reach of the endoscope, loop formation in the stomach, and flexibility of the gastroscope. The use of a colonoscope may overcome these problems., Objective: To report our experience with distal duodenal stent placement in 16 patients using a colonoscope., Methods: Multicenter, retrospective series of patients with a malignant obstruction at the level of the distal duodenum and proximal jejunum and treated by stent placement using a colonoscope. Main outcome measurements are technical success, ability to eat, complications, and survival., Results: Stent placement was technically feasible in 93% (15/16) of patients. Food intake improved from a median gastric outlet obstruction scoring system (GOOSS) score of 1 (no oral intake) to 3 (soft solids) (p = 0.001). Severe complications were not observed. One patient had persistent obstructive symptoms presumably due to motility problems. Recurrent obstructive symptoms were caused by tissue/tumor ingrowth through the stent mesh [n = 6 (38%)] and stent occlusion by debris [n = 1 (6%)]. Reinterventions included additional stent placement [n = 5 (31%)], gastrojejunostomy [n = 2 (12%)], and endoscopic stent cleansing [n = 1 (6%)]. Median survival was 153 days., Conclusion: Duodenal stent placement can effectively and safely be performed using a colonoscope in patients with an obstruction at the level of the distal duodenum or proximal jejunum. A colonoscope has the advantage that it is long enough and offers good endoscopic stiffness, which avoids looping in the stomach.

Background: Recently the use of a transparent hood attached to the tip of the colonoscope has been reported to be useful in cecal intubation, especially in difficult colonoscopy cases. However, patient comfort with or without the use of a transparent hood, the type of colonoscope most suitable for this device have not been fully evaluated., Methods: A total of 372 patients undergoing routine colonoscopy were evaluated. No sedatives were used as a principle, and patients with prior abdominal surgery were excluded. A single endoscopist performed all the examinations. Four types of colonoscopes were used: CF-230I and CF-Q240AI as a standard colonoscope, PCF-240I and PCF-P240AI as a small-caliber colonoscope (Olympus, Tokyo, Japan). A disposable transparent hood was used (Olympus, Tokyo, Japan). Patients were randomly divided into four groups; standard colonoscope without transparent hood (96 patients), standard colonoscope with transparent hood (82 patients), small-caliber colonoscope without transparent hood (102 patients), and small-caliber colonoscope with transparent hood (92 patients). Cecal intubation time, rate, modified visual analogue scale (VAS) of patient's pain, and technical difficulty were evaluated among the four groups., Results: Standard colonoscope with the transparent hood showed the shortest cecal intubation time, and lowest modified VAS scale of pain and technical difficulty among the four groups. However there was no significant difference with regard to small-caliber colonoscopes with or without the transparent hood., Conclusions: Transparent hood may be a handy and a cost-effective device for reducing pain and simplifying cecal intubation, especially when using a standard adult colonoscope in routine colonoscopy.

Background: Acute colorectal obstruction is a potentially life-threatening emergency that requires immediate surgical treatment. To avoid major postoperative complications, most surgeons advocate two-step surgery despite the increase in patient discomfort and cost. Various methods for performing one-step surgery have been reported including intraoperative colonic lavage, decompression with self-expandable metal stents, and transanal tube decompression., Methods: The authors present their experience performing transanal colonic decompression for 51 patients., Results: Endoscopic tube placement was successful for 43 (84%) of the 51 patients. The emergency clinical situation could be converted to semielective treatment in 37 cases (73%) (30 operations and 6 nonoperative interventions), and to an elective operation in 1 case. After successful colonic decompression, the rate of one-stage operations was 93% (28/30), as compared with 40% (4/10) if the decompression failed., Conclusion: Endoscopic tube decompression of acute colonic obstruction is an easy and cost-effective possibility for avoiding emergency operations with all their sequelae. Emergency surgery can be converted to semielective or elective surgery, markedly reducing the rate of staged operations.

Background: Nonrigid environments such as the human colon present unique challenges for the navigator in maintaining spatial orientation. Conventional wisdom suggests that a navigational aid, similar to a map, that provides critical shape information would be useful. This article presents a design concept for a colonoscopy navigational aid and the results of an experiment conducted to evaluate the display for supporting navigation and spatial orientation in simulated colonoscopy., Methods: A navigational aid was designed to present shape information in an augmented reality display. A total of 14 untrained subjects performed a colonoscopy procedure in rigid and nonrigid colon models, with and without the navigational aid display, in a Latin square design. Performance measures such as time, distance or efficiency of travel, and location and direction error were recorded, together with subjective measures of confidence and workload., Results: The results showed that, unlike navigating in rigid environments, the subjects spent more time navigating in the nonrigid environment (p < 0.01) and traveled a longer total distance (p = 0.01). The navigational aid had no effect on performance, as compared with the no aid condition. However, subjective measures showed that the subjects were more confident about their determination of location and direction (p < 0.01). They also preferred having the aid during navigation., Conclusion: A navigational aid or map that provides shape information does not seem to improve performance in colonoscopy. In fact, it may lead to a false sense of security about location and orientation in the colon. The value of a map for training purposes remains to be examined.

Background: Surgical experience and outcomes for hand-assisted laparoscopic colectomy were evaluated to define a learning curve., Methods: This study included 60 patients who underwent hand-assisted laparoscopic colectomies performed by a single surgeon. They were analyzed as three consecutive equal groups: A, B, and C. Pearson's chi-square test and one-way analysis of variance (ANOVA) were used to compare differences in demographics and perioperative parameters. Operative times were analyzed to document the learning curve for the procedure., Results: There were no significant differences between the three groups in terms of age, sex, operative procedure, or comorbidity. Groups B and C showed significantly shorter operative times, significantly earlier recoveries of gastrointestinal function, less blood loss, and shorter hospital stays than group A. The incidence of operative complications was not significantly different among the three groups (35% vs 5% vs 15%; p = 0.07)., Conclusions: Approximately 21 to 25 cases were needed to achieve proficiency in this series.

Background: Although magnetic endoscope imaging of the colonoscope via the Endoscope Positioning Detecting Unit (EPDU) has been studied to some extent in Europe, its application in the United States has been limited. The purposes of this study were to determine whether the technique enabled for accurate localization of the lesion and to determine if and how the device facilitated scope insertion and completion of the colonoscopic exam., Methods: Outpatient colonoscopies using the EPDU were performed by three experienced surgical endoscopists over a 5-month period. A specialized scope with electromagnetic coils or a regular scope with a magnetic probe insert in the instrument channel was used for the duration of the examination to identify loops and localize pathology., Results: A total of 80 colonoscopies were performed with the device. In two patients, the probe insert was removed prior to completion of the procedure; thus, the total number of examinations included in the study was 78. The EPDU was used in conjunction with transillumination to estimate the location of polyps or cancers in the 33 patients (42%) in whom such lesions were found. In the four patients who subsequently underwent operation, the lesion's location as estimated by EPDU was verified. In regard to the usefulness of the device during insertion, the EPDU led to the discovery of loops and to the application of pressure that resulted in prompt completion of the examination in 28% of cases (deemed most useful). In 33% of cases, the device identified loops and led to the application of abdominal wall pressure and early position changes, thus facilitating the examination; however it did not lead to its immediate or rapid completion. In 39% of cases, the device was not required or used for insertion due to the simple nature of the examination., Conclusions: The EPDU was accurate in estimating lesion location. The device also holds promise as an aid in the completion of difficult exams (about 30% of cases in this study).

Background: The present study was designed to investigate whether there is a correlation between manual skills in laparoscopic procedures and manual skills in flexible endoscopy., Methods: In a prospective study using laparoscopy and endoscopy simulators (MIST-VR, and GI-Mentor II), 24 consecutive subjects (gastrointestinal surgeons, novice and experienced gastroenterologists, and untrained subjects) were asked to perform laparoscopic and endoscopic tasks. Their performance was assessed by the simulators' software and by observers blinded to the levels of subjects' experience. Performance in experienced vs inexperienced subjects was compared. Score pairs of three parameters--time, errors, and economy of movement--were also compared., Results: Experienced subjects performed significantly better than inexperienced subjects on both tasks in terms of time, errors, and economy of movement (p < 0.05). All three performance parameters in laparoscopy and endoscopy correlated significantly (p < 0.02)., Conclusion: Both simulators can distinguish between experienced and inexperienced subjects. Observed skills in simulated laparoscopy correlate with skills in simulated flexible endoscopy. This finding may have an impact on the design of training programs involving both procedures.

Background: The European Association of Endoscopic Surgery (EAES) initiated a consensus development conference on the laparoscopic resection of colon cancer during the annual congress in Lisbon, Portugal, in June 2002., Methods: A systematic review of the current literature was combined with the opinions, of experts in the field of colon cancer surgery to formulate evidence-based statements and recommendations on the laparoscopic resection of colon cancer., Results: Advanced age, obesity, and previous abdominal operations are not considered absolute contraindications for laparoscopic colon cancer surgery. The most common cause for conversion is the presence of bulky or invasive tumors. Laparoscopic operation takes longer to perform than the open counterpart, but the outcome is similar in terms of specimen size and pathological examination. Immediate postoperative morbidity and mortality are comparable for laparoscopic and open colonic cancer surgery. The laparoscopically operated patients had less postoperative pain, better-preserved pulmonary function, earlier restoration of gastrointestinal function, and an earlier discharge from the hospital. The postoperative stress response is lower after laparoscopic colectomy. The incidence of port site metastases is <1%. Survival after laparoscopic resection of colon cancer appears to be at least equal to survival after open resection. The costs of laparoscopic surgery for colon cancer are higher than those for open surgery., Conclusion: Laparoscopic resection of colon cancer is a safe and feasible procedure that improves short-term outcome. Results regarding the long-term survival of patients enrolled in large multicenter trials will determine its role in general surgery.

Background: In the laparoscopic surgical treatment of early stage colorectal carcinomas, intraoperative tumor site identification is often difficult. We developed a novel marking method using a magnetic marking clip and a modified magnetometer system., Methods: We applied magnetic marking clips at the tumor site during preoperative colonoscopy and identified the clip site with a magnetic marking clip detector system (MMCDS) of our design. Eleven patients who underwent laparoscopic colectomy were studied., Results: In a basic ex vivo study, magnetic bodies of more than 300 mT magnetic force were easily detected with a 100% detection ratio. In a clinical study, the marking site was detected in all 11 patients. The mean length between the detected site and clip along the longitudinal bowel axis was 14.1 mm (SD 5.6). The mean detection time was 2.4 min (SD 0.2)., Conclusion: MMCDS accurately identifies tumor sites. This method may be useful for tumor site identification during laparoscopic colectomy.

There are not enough trained colonoscopists to cope with the present recommended number of examinations required for diagnostic and surveillance purposes. If colorectal cancer screening is to be introduced, endoscopic examination of the large bowel needs to be easier to learn and significantly quicker to carry out. The 'Bladen system', first described in 1993, is a non-radiological method of visualising the path of the endoscope, using magnetic drive coils under the patient and a chain of sensors along the biopsy channel of the instrument. In 1998, results were published using a novel computer graphics system (the RMR system), in which a much more realistic image of the endoscope could be produced using the stored positional data from the Bladen system. The RMR system has been further refined to allow, for the first time ever, accurate measurement of the effect of the passage of a colonoscope along the bowel on the lengths of different segments of the large intestine. The results obtained in 232 patients undergoing colonoscopy are analysed. In 77 of the patients, a stiffening overtube is used to splint the sigmoid colon once the endoscope is at or beyond the splenic flexure. The mean time taken to pass the colonoscope across the transverse colon is significantly shorter (p < 0.001) when an overtube is used, despite it resulting in significant lengthening of the transverse colon. The routine use of a stiffening overtube can be expected to reduce the total procedure time by between 10 and 20%.

A testing device is developed that determines the stiffness, or flexural rigidity, of an endoscope at specific locations down its length by subjecting it to a compressive axial force, a situation similar to the actual forces applied to the endoscope during a clinical procedure. The endoscope is made to deform in a similar fashion to a slender buckled column and the force causing this deformation is related to the flexural rigidity using column buckling theory. A direct relationship between the critical load needed to cause buckling and the square of column length L is demonstrated experimentally and is expected theoretically, giving confidence in the application of column buckling theory to endoscope testing. Additional confidence in the validity of the column buckling test results is obtained by their similarity to data obtained by subjecting the endoscope to a transverse load, determining deflection, and modelling the endoscope as a bent elastic beam. Several makes and models of endoscopes were tested, with flexural rigidity values typically ranging between 160 to 240 Ncm2. The effect of a metal stiffener inserted in an endoscope's accessory channel is quantified, as is the change in flexural rigidity down the insertion shaft of a graded-stiffness endoscope. Significant differences in flexural rigidity were obtained between identical endoscopes, each sharing similar usage histories, indicating the need for flexural rigidity measurements for each individual endoscope of a particular model line, though a more extensive study is required to reliably determine scope-to-scope stiffness variations for a particular model line.

Colonoscopy involves advancing a flexible endoscope into and along the entire length of the colon. The procedure can be painful and carries the risk of perforating the organ, yet very little is known of the forces involved. A device to measure the forces exerted on the endoscope during colonoscopy is described. The device features a handle designed in the shape of a hinged split cylinder that locks around the endoscope, gripping it tightly. The handle has two parts, an inner part that grips the endoscope, and an outer part that is gripped by the endoscopist. The two parts are joined together by members that transmit the forces through to the endoscope. One of the members incorporates strain gauges that measure the torque applied to the endoscope, as well as the push and pull forces. The handle can easily be unlocked and moved along the endoscope as the colonoscopy proceeds. The device is used to measure the forces applied to the endoscope during 11 routine colonoscopies, and summary results are presented. These are believed to be the first accurate measurements of the forces exerted during colonoscopy.