Risk Factors of Delayed Bleeding After Cold Snare Polypectomy for Colorectal Polyps: A Multicenter Study.

BACKGROUND: Delayed bleeding (DB) rarely occurs after cold snare polypectomy (CSP) for colorectal polyps, but no large-scale studies have investigated this. The present study evaluated the rate, characteristics, and risk factors of DB of CSP. METHODS: We conducted a multicenter retrospective study at 10 Japanese institutions. A total of 18,007 patients underwent CSP for colorectal polyps ≤ 10 mm in size from March 2015 to September 2019, and cases of DB (DB group) were analyzed for the rate, antithrombotic drugs, polyp size, morphology, location, and risk factors. As a control, 269 non-bleeding cases (non-DB group) with 606 polyps who underwent CSP at the same 10 facilities in the 2-week study period were extracted. RESULTS: We analyzed 26 DB cases with 28 lesions, and the total DB rate was 0.14% (26/18,007). The DB group had significantly higher rates of using antiplatelets (42.3% vs. 13.0%, p < 0.001) and anticoagulants (19.2% vs. 2.6%, p = 0.002), and significantly higher rates of polyp size ≥ 5 mm (67.9% vs. 45.2%, p = 0.015), rectal lesion (25.0% vs. 6.6%, p = 0.003), and polypoid lesion (89.3% vs. 55.3%, p < 0.001) than the non-DB group. A multivariate analysis (odds ratio; 95% confidence interval) for patient characteristics showed antiplatelet use (4.521; 1.817-11.249, p = 0.001) and anticoagulant use (7.866; 20.63-29.988, p = 0.003) as independent risk factors for DB. Polyp size ≥ 5 mm (3.251; 1.417-7.463, p = 0.005), rectal lesion (3.674; 1.426-9.465, p = 0.007), and polypoid lesion (7.087; 20.81-24.132, p = 0.002) were also risk factors for lesion characteristics. CONCLUSIONS: The rate of DB was 0.14% and antithrombotic drug use, polyp size, location, and morphology were related to it.

Risk of lymph node metastasis after endoscopic treatment for rectal NETs 10 mm or less.

PURPOSE: For rectal neuroendocrine tumors (NETs) ≤ 10 mm, endoscopic resection is a standard treatment. However, there is no consensus whether additional surgery should be performed for patients at risk of lymph node metastasis (LNM) after endoscopic resection. The purpose of this study was to analyze the results of endoscopic resection and additional surgery of rectal NETs, thereby clarify the characteristics of cases with LNM. METHODS: This study was a multicenter retrospective cohort study conducted at 12 Japanese institutions. A total of 132 NETs ≤ 10 mm were analyzed regarding various therapeutic results. A comparative analysis was performed by dividing the cases into two groups that underwent additional surgery or not. Furthermore, the relationship between tumor size and LNM was examined. RESULTS: The endoscopic treatments were 12 endoscopic mucosal resections (EMR), 58 endoscopic submucosal resections with ligation (ESMR-L), 29 precutting EMRs, and 33 endoscopic submucosal dissections (ESD). The R0 resection rates of EMR were 41.7%, and compared to this rate, other three treatments were 86.2% (p < 0.001), 86.2% (p = 0.005), and 97.0% (p < 0.001), respectively. There were 41 non-curative cases (31.1%), and 13 had undergone additional surgery. Then, LNM was observed in 4 of the 13 patients, with an overall rate of LNM of 3.0% (4/132). The rate of positive lymphatic invasion and the rate of LNM by tumor size ≤ 6 mm and 7-10 mm were 9.7 vs. 15.4% (p = 0.375) and 0 vs. 10.3% (p = 0.007). CONCLUSIONS: A multicenter study revealed the priority of each endoscopic resection and the low rate of LNM for rectal NETs ≤ 6 mm.

Recurrence rate and lesions characteristics after cold snare polypectomy of high-grade dysplasia and T1 lesions: A multicenter analysis.

BACKGROUND AND AIM: High-grade dysplasia (HGD) and T1 lesions are accidentally resected by cold snare polypectomy (CSP) and the characteristics, and follow-up of them has not been reported. In this study, we analyzed the histopathological findings and recurrence of them. METHODS: This was a multicenter retrospective-cohort study. We collected HGD and T1 lesions of ≤ 10 mm resected by CSP among 15 520 patients receiving CSP from 2014 to 2019 at nine related institutions, and we extracted only cases receiving definite follow-up colonoscopy after CSP of HGD and T1 lesions. We analyzed these tumor's characteristics and therapeutic results such as R0 resection and local recurrence and risk factors of recurrence. RESULTS: We collected 103 patients (0.63%) and extracted 80 lesions in 74 patients receiving follow-up colonoscopy for CSP scar. Mean age was 68.4 ± 12.0, and male rate was 68.9% (51/80). The mean tumor size (mm) was 6.6 ± 2.5, and the rate of polypoid morphology and rectum location was 77.5% and 25.0%. The rate of magnified observation was 53.8%. The rates of en bloc resection and R0 resection were 92.5% and 37.5%. The local recurrence rate was 6.3% (5/80, median follow-up period: 24.0 months). The recurrence developed within 3 months after CSP for four out of five recurrent cases. Comparing five recurrent lesions to 75 non-recurrent lesions, a positive horizontal margin was a significant risk factor (60.0% vs 10.7%, P < 0.001). CONCLUSIONS: High-grade dysplasia and T1 resected by CSP were analyzed, and the local recurrence rate of them was substantially high.

The efficacy of tumor characterization and tumor detectability of linked color imaging and blue laser imaging with an LED endoscope compared to a LASER endoscope.

OBJECTIVES: An endoscope with a light-emitting diode (LED) light source which has a 2-mm close-distance observation function without magnification, has been marketed, enabling linked color imaging (LCI) and blue laser imaging (BLI) for tumor detection and characterization. We analyzed the efficacy of a LED endoscope compared to a LASER endoscope. METHODS: We retrospectively reviewed 272 lesions observed using the LED endoscopic system (Fujifilm Co., Tokyo, Japan) from May 2018 to September 2019. The Japanese NBI Classification was used for tumor characterization. We analyzed the diagnostic accuracy and confidence level. Sixty-one lesions observed with both the LED and magnified LASER endoscopes were also analyzed to compare the diagnostic accuracy. Regarding the tumor detectability, we calculated color difference values (CDVs) and brightness values (BVs) of white-light imaging, BLI, and LCI modes between the two endoscopes for each tumor. RESULTS: The mean polyp size was 9.2 ± 11.3 mm. Histology showed 71 sessile serrated lesions, 193 adenoma and high-grade dysplasias, and 8 T1 cancers. The diagnostic accuracy of tumors ≥ 10 and < 10 mm was 72.0% and 92.9% (p < 0.001), respectively and the high confidence rate was 93.8%. The diagnostic accuracy of LED (77.0%) was a little higher than that of LASER without magnification (65.6%, p = 0.16) but was not inferior to that of LASER with magnification (82.0%, p = 0.50). The respective CDVs of LED and LASER endoscopes were 20.6 ± 11.2 and 21.6 ± 11.2 for LCI (p = 0.30), and the respective BVs were 210.0 ± 24.2 and 175.9 ± 21.1 (p < 0.001). CONCLUSIONS: A LED endoscope with close-distance observation improved tumor detection and characterization due to high brightness.

Local recurrence and its risk factors after cold snare polypectomy of colorectal polyps.

BACKGROUND: Local recurrence after cold snare polypectomy (CSP) of colorectal polyps has not been well analyzed. In this study, we analyzed the characteristics of local recurrence. METHODS: We retrospectively reviewed consecutive lesions resected by CSP from 2014 to 2016 and lesions that were followed up at ≥ 10 months after CSP, were analyzed. Our indication for CSP was a benign tumor of < 15 mm in size. We analyzed local recurrence and its risk factors using multivariate analyses. In addition, we compared lesions of ≥ 10 mm and < 10 mm. Moreover, therapeutic methods for recurrence were analyzed. RESULTS: Finally, we analyzed 554 cases out of 820 consecutive cases. The mean polyp size was 5.3 ± 2.8 mm and the en bloc resection and histopathological complete resection rates were 99.3% and 70.2%, respectively. The overall recurrence rate was 1.9% (mean follow-up period: 13.0 ± 4.0 months). Significant differences were observed between 11 recurrent lesions and 543 lesions without recurrence regarding polyp size (8.0 ± 3.7 mm vs. 5.2 ± 2.7 mm, p < 0.001), rate of sessile-serrated polyp (27.3% vs. 3.0%, p < 0.001), and histopathological positive margin (45.4% vs. 3.7%, p = 0.019). Multivariate analyses showed that a histopathological positive margin was the only significant risk factor for local recurrence (OR 16.600, 95% CI 3.707-74.331, p < 0.001). Regarding the comparison between 74 lesions of ≥ 10 mm and 480 lesions of < 10 mm, significant differences were observed in the en bloc resection rate (93.2% vs. 100%, p < 0.001), high-grade dysplasia rate (8.1% vs. 0.8%, p < 0.001), and histopathological complete resection rate (54.0% vs. 72.7%, p = 0.001). The recurrence rates of these two groups were 5.4% and 1.4%, respectively (p = 0.069). All recurrent cases could be resected with repeat CSP. CONCLUSIONS: The local recurrence rate after CSP for lesions of < 10 mm was 1.4%. CSP was not recommended for lesions of ≥ 10 mm due to high rates of recurrence and malignancy.

Efficacy of scissor-type knives for endoscopic mucosal dissection of superficial gastrointestinal neoplasms.

Endoscopic submucosal dissection (ESD) for superficial gastrointestinal neoplasms has become widespread. However, certain aspects of the procedure remain difficult to manage, such as intraoperative bleeding and perforation. There are two kinds of scissor-type knife: the Clutch Cutter (Fujifilm Co., Tokyo, Japan) and the SB knife (Sumitomo Bakelite Co., Tokyo, Japan). These knives have different features from other types of ESD knives and enable the performance of all ESD procedures, including mucosal incision, submucosal dissection, and hemostasis. The standard approach with scissor-type knives involves first grabbing the tissue and then incising or dissecting it. Theoretically, perforation as a result of unintentional movement should never happen with scissor-type knives compared to needle- or blade-type knives, which may induce perforation through unintentional movement. Moreover, the rates of severe bleeding and self-completion of ESD with scissor-type knives by non-experts were reported to be significantly better than for other knives. Thus, scissor-type knives can resolve these problems and help to further standardize ESD globally. In this review, we summarize reports on the efficacy of such scissor-type knives for ESD of gastrointestinal tumors. We also present the pocket-creation method and the application of traction devices, such as dental floss and S-O clips (Zeon Medical Co., Tokyo, Japan) for improving the performance of ESD with a Clutch Cutter.

Efficacy of precutting endoscopic mucosal resection with full or partial circumferential incision using a snare tip for difficult colorectal lesions.

BACKGROUND: We analyzed the efficacy of precutting endoscopic mucosal resection (EMR), which is a method of making a full or partial circumferential mucosal incision around a tumor with a snare tip for en bloc resection. METHODS: We reviewed cases from 2011 to 2018 in which precutting EMR (n = 167) and standard EMR (n = 557) were performed for lesions of 10 - 30 mm. Precutting EMR was indicated for benign lesions of 20 - 30 mm or lesions of < 20 mm for which standard EMR was difficult. Through propensity score matching of the two groups, the therapeutic outcomes for 35 lesions of ≥ 20 mm and 98 lesions of < 20 mm in each group were analyzed. RESULTS: In the two sizes of lesion, there were significant differences between the precutting and standard groups in the en bloc resection rate (≥ 20 mm 88.6 % vs. 48.5 %, P < 0.001; < 20 mm 98.0 % vs. 85.7 %, P = 0.004) and the histological complete resection rate (≥ 20 mm 71.4 % vs. 42.9 %, P = 0.02; < 20 mm 87.8 % vs. 67.3 %, P < 0.001). CONCLUSION: Precutting EMR enabled high en bloc resection rates in cases involving difficult lesions.

High Enhancement Settings for White Light Observation Improves Colorectal Polyp Visibility in Color Difference Value and an Endoscopist's Visibility.

BACKGROUND/AIMS: Settings of structure and color enhancement (CE) change view of white light imaging and a preset low enhancement setting is used regularly. The aim of this study was to investigate whether higher enhancement settings increased colorectal lesions' visibility with endoscopists' visibility scoring and objective color difference (CD) value. METHODS: From April 2015 to September 2015, we analyzed 27 pictures and 100 videos of colorectal lesions. Combinations of structure enhancement (B3, A3, A5) and CE (CE 0, 1, 3) were evaluated and CD values of 2 corresponding modes (high enhancement: A5 + CE3, preset low enhancement: A3 + CE0) were calculated using marketed software. In the video, these 2 modes were evaluated. All pictures and movies were graded by 4 endoscopists using visibility scores: score 4 (excellent) to score 1 (poor). RESULTS: The scores of A3 + CE0 (2.74 ± 1.09) were significantly lower than those of all other higher enhancement settings such as B3 + CE1 (3.11 ± 1.08), A3 + CE1 (3.33 ± 0.91), and A5 + CE3 (3.56 ± 0.74; p < 0.001). The CD value of A5 + CE3 was significantly higher than A3 + CE0 (20.2 ± 6.9 vs. 12.9 ± 5.6, p < 0.001). In the video, the scores for A5 + CE3 were significantly higher than A3 + CE0 (3.27 ± 0.83 vs. 2.53 ± 1.05, p < 0.001). CONCLUSIONS: Higher enhancement settings increased visibility of colorectal lesions.

An Additional 30-s Observation of the Right-Sided Colon with Narrow Band Imaging Decreases Missed Polyps: A Pilot Study.

INTRODUCTION: Previous narrow-band imaging (NBI) was dark and reported not to be useful for polyp detection. In this study, we analyzed the efficacy of an additional 30-s observation of the right-sided colon with the recent bright high-resolution NBI. METHODS: We enrolled patients undergoing colonoscopy from February 2015 to May 2017 in two institutions. All procedures were performed with the latest system (EVIS LUCERA ELITE, Olympus). The cecum and ascending colon were first observed with white light imaging (WLI) in both the NBI and WLI group. Then, the colonoscope was re-inserted, and the cecum and ascending colon were observed for an additional 30 s. In this second observation, NBI was performed for the first 130 patients in the NBI group and WLI for the next 130 in the WLI group. The number of adenoma and sessile serrated polyps (ASPs) in the second observation were examined in both groups. According to our initial pilot study, the sample size was estimated at 126. RESULTS: In the first observation, the number of ASPs was 72 in the NBI group and 72 in the WLI group (p = 1.0). In the second observation, the number of ASPs was 23 in the NBI group and 10 in the WLI group (p = 0.02). The polyp and adenoma detection rates in the second observation were 16.2% and 12.3% in the NBI group and 7.7% (p = 0.03) and 6.2% (p = 0.09) in the WLI group. CONCLUSIONS: The additional 30-s observation with recent NBI decreased missed polyps in the right-sided colon.

Linked color imaging improves the visibility of various featured colorectal polyps in an endoscopist's visibility and color difference value.

PURPOSE: Linked color imaging (LCI) by laser endoscopy is a novel narrow band light observation. In this study, we analyzed the efficacy of LCI for improving the various featured colorectal polyp's visibility utilizing a subjective endoscopist's visibility scoring and objective color difference (CD) value. METHODS: We retrospectively reviewed two pictures both with white light (WL) and LCI for 54 consecutive neoplastic polyps 2-20 mm in size. All pictures were evaluated by four endoscopists according to a published polyp visibility score from four (excellent visibility) to one (poor visibility). Additionally, we calculated CD value between each polyp and surrounding mucosa in LCI and WL using an original software. RESULTS: The mean polyp visibility scores of LCI (3.11 ± 1.05) were significantly higher than those of WL (2.50 ± 1.09, P < 0.001). The ratio of an endoscopist's poor visibility (polyp visibility scores 1 and 2) was significantly lower in LCI (27.9%) than WL (55.6%, P < 0.001). With respect to the CD analysis, the CD value of LCI was significantly higher than that of WL (33.3 ± 13.9 vs. 20.7 ± 13.6, P < 0.001). In a subgroup analysis, the polyp visibility scores and CD values of LCI about 24 diminutive polyps (≤5 mm) were higher than those of WL (3.29 ± 0.99 vs. 2.12 ± 0.99, P < 0.001; 31.6 ± 12.8 vs. 14.7 ± 7.6, P < 0.001). Additionally, the polyp visibility scores and CD values of LCI for polyps with any location, size, histology, and morphology were significantly higher than those of WL. CONCLUSIONS: LCI improved the various featured polyp's visibility compared to WL in both polyp visibility scores and CD value.

Histopathological analysis of cold snare polypectomy and its indication for colorectal polyps 10-14 mm in diameter.

BACKGROUND AND AIM: Cold snare polypectomy (CSP) is commonly used for treating colorectal polyps <10 mm in diameter. We evaluated the analysis and safety of CSP for larger polyps. METHODS: We retrospectively analyzed 1006 colorectal polyps resected with CSP. Indication for CSP was polyps 2-14 mm that were diagnosed as benign neoplastic polyp by magnifying endoscopy. Various clinicopathological characteristics were analyzed. Multivariate analyses were used to determine the independent risk factors for failure of complete CSP resection. With respect to polyp size, we compared the therapeutic outcomes between polyps <10 mm and ≥10 mm. Additionally, the presence of muscularis mucosa in resected specimens was analyzed. RESULTS: Rates of en bloc resection and postoperative hemorrhage were 98.8% and 0.1%, respectively. Seven hundred and ninety-one neoplastic lesions were analyzed and negative margins were found in 70.5% of the lesions, Multivariate analysis showed that non-polypoid morphology, histology of intramucosal cancer + high-grade adenoma and sessile serrated adenoma and polyp were significant factors for incomplete resection. With respect to the difference between lesions ≥10 mm than in those <10 mm, rates of cancer and positive/unclear margins were significantly higher (5.0% vs 0.9%, P < 0.001; 40.6% vs 27.7%, P = 0.007) in the ≥10 mm with rates of postoperative hemorrhage not significantly different (0.8% vs 0.0%). Additionally, the loss of muscularis mucosa was found in 27.8% of all lesions. CONCLUSION: CSP is a safe procedure for polyps 2-14 mm. However, CSP has limitations in terms of the histopathological margin and loss of muscularis mucosa in specimens.

Safety and Efficacy of a Same-Day Low-Volume 1 L PEG Bowel Preparation in Colonoscopy for the Elderly People and People with Renal Dysfunction.

INTRODUCTION: A same-day low-volume 1 L polyethylene glycol (PEG) for bowel preparation before colonoscopy was developed to improve patients' compliance. We aimed to evaluate the efficacy and safety of this regimen especially for the elderly and patients with renal dysfunction. METHODS: All consecutive patients who underwent colonoscopy in our center from November 2014 to September 2015 were included. Patients undertook a low-residue diet with 10 mL sodium picosulfate 1 day before colonoscopy. Subsequently, they had 1 L low-volume PEG (MoviPrep) and 0.5 L water 4 h before the examination. Clinical outcomes, including cleansing level using the Boston bowel preparation score (BBPS), in the elderly and special-elderly (65-79 and ≥80 years old) were analyzed and compared with the non-elderly (18-64 years old). Additionally, patients with renal dysfunction were analyzed with respect to both complications and changes in blood parameters. RESULTS: A total of 5427 patients (mean age: 64.5 ± 13.8) were analyzed. The rate of BBPS ≥ 6 in the elderly (2761 patients), special-elderly (565 patients), and non-elderly (2101 patients) was 94.1, 91.8, and 94.6 %, respectively. In the special-elderly, the rate of renal dysfunction was 14.8 %, and no severe complications were detected after colonoscopy. Additionally, there were no severe complications in 86 patients with renal dysfunction, though elevation of hematocrit was shown after intake of 1 L PEG (before, 36.7 ± 6.1 vs. after, 39.0 ± 5.7, P = 0.006). CONCLUSIONS: Our study shows the safety and efficacy of same-day low-volume 1 L PEG bowel preparation in colonoscopy for the elderly and patients with renal dysfunction.

High incidence of metachronous advanced adenoma and cancer after endoscopic resection of colon polyps ≥20 mm in size.

BACKGROUND AND AIM: There are limited studies on incidence rates of metachronous neoplastic lesions after resecting large colorectal polyps. In the present study, we analyzed metachronous lesions after endoscopic resection of colorectal polyps ≥20 mm in size. METHODS: We retrospectively analyzed consecutive patients who underwent endoscopic resection of polyps from 2006 to 2013 at two affiliated hospitals. All patients underwent at least two total colonoscopies before follow up to ensure minimal missed polyps. Only patients who had follow-up colonoscopy annually after resection were recruited. We separated patients according to size of polyp resected; there were 239 patients in the ≥20-mm group and 330 patients in the <20-mm group. Clinical characteristics and cumulative rates of metachronous advanced adenoma and cancer in both groups were analyzed. Advanced adenoma was defined as a neoplastic lesion ≥10 mm in size and adenoma with a villous component. RESULTS: Cumulative rate of development of metachronous advanced adenoma and cancer in the ≥20-mm group was significantly higher than in the <20-mm group (22.9% vs. 9.5%, P < 0.001) at 36 months. There was also more development of small polyps 5-9 mm in the ≥20-mm group than in the <20-mm group (45.2% vs. 28.8%, P < 0.001). With respect to metachronous lesions, there were more right-sided colonic lesions in the ≥20-mm group than in the <20-mm group (78.8% vs. 50.0%, P = 0.015). CONCLUSION: High incidence rates of development of metachronous neoplastic lesions were detected after resection of colorectal polyps ≥20 mm in size.

Improvement in the visibility of colorectal polyps by using blue laser imaging (with video).

BACKGROUND: Fujifilm developed blue laser imaging (BLI) via a laser light source with a narrow-band light observation function. It has a brighter BLI bright mode for tumor detection. OBJECTIVE: To investigate whether the BLI bright mode can improve the visibility of colorectal polyps compared with white light (WL). DESIGN: We studied 100 colorectal polyps (protruding, 42; flat, 58; size, 2-20 mm) and recorded videos of the polyps by using the BLI bright mode and WL at Kyoto Prefectural University of Medicine and Fukuoka Chikushi University Hospital. The videos were evaluated by 4 expert endoscopists and 4 nonexperts. Each endoscopist evaluated the videos in a randomized order. Each polyp was assigned a visibility score from 4 (excellent visibility) to 1 (poor visibility). SETTING: Japanese academic units. MAIN OUTCOME MEASUREMENTS: The visibility scores in each mode and their relationship to the clinical characteristics were analyzed. RESULTS: The mean visibility scores of the BLI bright mode were significantly higher than those of WL for both experts and nonexperts (experts, 3.10 ± 0.95 vs 2.90 ± 1.09; P = .00013; nonexperts, 3.04 ± 0.94 vs 2.78 ± 1.03; P < .0001). For all nonexperts, the visibility scores of the BLI bright mode were significantly higher than those of WL; however, these scores were significantly higher in only 2 experts. For experts, the mean visibility scores of the BLI bright mode was significantly higher than those of WL for flat polyps, neoplastic polyps, and polyps located on the left side of the colon and the rectum. LIMITATIONS: Small sample size and review of videos. CONCLUSIONS: Our study showed that polyps were more easily visible with the BLI bright mode compared with WL. ( CLINICAL TRIAL REGISTRATION NUMBER: UMIN000013770.).

Risk of lens cloudiness during colorectal endoscopic submucosal dissection and ability of a novel lens cleaner to maintain and restore endoscopic view.

BACKGROUND AND AIM: Generally, colorectal endoscopic submucosal dissection (ESD) cannot be carried out with severe lens cloudiness. We examined the occurrence of lens cloudiness during ESD as well as the efficacy of a novel cleaner for it. METHODS: This study was a prospective study compared to historical control. First, we analyzed 103 ESD cases using standard cleaner at the Kyoto Prefectural University of Medicine in 2012. Relationship between lens cloudiness and clinical characteristics of lesions was analyzed. Lens cloudiness was recorded as grade 0 (clear) to grade 2 (very unclear). Then, we recruited 92 consecutive patients who underwent colorectal ESD using the novel cleaner from August 2013 to July 2014. The cleaner was applied on top of the lens before procedure and ability to prevent lens cloudiness was tested. Additionally, the novel cleaner was injected from endoscopic channel into a space created by endoscopic hood and colonic wall in seven cases with grade 1 or 2 of lens cloudiness and the ability to clean lens cloudiness inside the colon was tested. RESULTS: Rate of severe lens cloudiness was 8.7%. Multivariate analysis showed that severe lens cloudiness was related with severe submucosal fatty tissue (P < 0.001). The novel cleaner had significantly less cloudiness cases compared to the standard cleaner (14.1% vs 33.0%, P = 0.002). Additionally, the novel cleaner enabled us to clean lens cloudiness in all seven cases. CONCLUSION: Lens cloudiness during ESD was associated with submucosal fatty tissue. Effective lens cleaner should be used to prevent and clean lens cloudiness.

Prevention of colonic spasm using L-menthol in colonoscopic examination.

PURPOSE: The detailed efficacy of intraluminal L-menthol for preventing colonic spasm is not known. The aim of this study was to evaluate the effectiveness of L-menthol in preventing colonic spasm during colonoscopy. METHODS: We analyzed 65 patients (mean age: 71.7 years; 49 men and 16 women) who were administered 0.8% L-menthol (MINCLEA, Nihon Seiyaku, Tokyo, Japan) intraluminally for severe colonic spasm during colonoscopic examination at Kyoto Prefectural University of Medicine between February 2012 and May 2013. The efficacy of L-menthol was defined as the absence of colonic spasm during a period of 30 s, and its effect was evaluated at 30 s, 1 min, and 5 min after administration. Additionally, various characteristics of these patients were analyzed. Twenty-seven patients with severe colonic spasm were administered intraluminal water and assessed as controls. RESULTS: L-Menthol was effective in preventing colonic spasms in 60.0%, 70.8%, and 46.5% of patients at 30 s, 1 min, and 5 min, respectively. In contrast, water was effective in 22.2%, 29.6%, and 48.1% of patients at 30 s, 1 min, and 5 min, respectively. There was a significant difference about the efficacy at 30 s and 1 min between L-menthol and water (P = 0.0009, P = 0.0006). CONCLUSIONS: L-Menthol (0.8%) was effective in preventing colonic spasm during colonoscopic examination.

Endoscopic mucosal resection for middle and large colorectal polyps with a double-loop snare.

BACKGROUND/AIMS: This study aimed to analyze the endoscopic mucosal resection (EMR) with a novel uniquely shaped, double-loop snare (Dualoop, Medico's Hirata Inc., Tokyo, Japan) for colorectal polyps. METHODS: This was a clinical trial conducted in two referral centers, Kyoto Prefectural University of Medicine and National Cancer Center Hospital in Japan. First, the firmness of various snares including 'Dualoop' was experimentally analyzed with a pressure gauge. Five hundred and eighty nine consecutive polyps that underwent EMR with 'Dualoop' were compared to 339 polyps with the standard round snare. Lesion characteristics, en bloc resection, and complications were analyzed. RESULTS: 'Dualoop' had the most firmness among the various snares. The average tumor size was 9.3 mm (5-30), and en bloc resection was achieved in 95.4%. The rate of en bloc resection for middle polyps 15-19 mm in diameter was significantly higher with the 'Dualoop' than that with the round snare (97.9 vs. 80.0%, p < 0.05). The rate of en bloc resection was 64.7% for large polyps ≥20 mm in diameter using 'Dualoop'. Higher age, larger tumor size, and superficial polyps were associated with the failure of en bloc resection. CONCLUSION: EMR with 'Dualoop' was effective for resecting both middle and large polyps en-bloc.

[Pancreatic pseudocyst with fistula to the common bile duct and the duodenum].

A 35-year-old man was hospitalized for severe acute pancreatitis. On the 24th hospital day, CT scan showed a pancreatic pseudocyst in the head of the pancreas. Conservative medical treatment for 1 month was not effective, and CT scan revealed a fistulous communication of the pseudocyst to the common bile duct and duodenum. After the formation of a fistulous communication, we detected common bile duct stones composed of fatty acid calcium and we removed them endoscopically. The pseudocyst gradually decreased in size and disappeared 4 months later. Follow-up CT scan showed no sign of recurrence.

Utility of an artificial intelligence system for classification of esophageal lesions when simulating its clinical use.

Previous reports have shown favorable performance of artificial intelligence (AI) systems for diagnosing esophageal squamous cell carcinoma (ESCC) compared with endoscopists. However, these findings don't reflect performance in clinical situations, as endoscopists classify lesions based on both magnified and non-magnified videos, while AI systems often use only a few magnified narrow band imaging (NBI) still images. We evaluated the performance of the AI system in simulated clinical situations. We used 25,048 images from 1433 superficial ESCC and 4746 images from 410 noncancerous esophagi to construct our AI system. For the validation dataset, we took NBI videos of suspected superficial ESCCs. The AI system diagnosis used one magnified still image taken from each video, while 19 endoscopists used whole videos. We used 147 videos and still images including 83 superficial ESCC and 64 non-ESCC lesions. The accuracy, sensitivity and specificity for the classification of ESCC were, respectively, 80.9% [95% CI 73.6-87.0], 85.5% [76.1-92.3], and 75.0% [62.6-85.0] for the AI system and 69.2% [66.4-72.1], 67.5% [61.4-73.6], and 71.5% [61.9-81.0] for the endoscopists. The AI system correctly classified all ESCCs invading the muscularis mucosa or submucosa and 96.8% of lesions ≥ 20 mm, whereas even the experts diagnosed some of them as non-ESCCs. Our AI system showed higher accuracy for classifying ESCC and non-ESCC than endoscopists. It may provide valuable diagnostic support to endoscopists.