Bong Min Ko

An adequate level of training for technical competence in screening and diagnostic colonoscopy: a prospective multicenter evaluation of the learning curve

BACKGROUND Various training programs in colonoscopy recommend that trainees should perform at least 100 to 200 procedures to be considered technically competent at diagnostic colonoscopy. OBJECTIVE Our purpose was to determine the adequate level of training for technical competence in screening and diagnostic colonoscopy. DESIGN A prospective multicenter trial. SETTING Fifteen tertiary care academic medical centers. PATIENTS Over 8 months we prospectively evaluated the procedures of 24 first-year GI fellows in 15 tertiary care academic medical centers. A total of 4351 colonoscopies were assessed prospectively with variable clinical factors. INTERVENTION Cecal intubation was documented by photographing the identified cecal landmarks, including the appendiceal orifice and the ileocecal valve. MAIN OUTCOME MEASUREMENTS Acquisition of competence (success rate) was evaluated for colonoscopic training on the basis of 2 objective criteria: (1) adjusted completion rate (>90%) and (2) cecal intubation time (<20 minutes). RESULTS The overall success rate was 83.5% (3635/4351). The mean cecal intubation time was 9.23 +/- 4.63 minutes. The success rate significantly improved and reached the requisite standard of competence after 150 procedures (71.5%, 82.6%, 91.3%, 94.4%, 98.4%, and 98.7%, respectively, for every 50 consecutive blocks). The polyp detection rate did not improve significantly during the 8 months and was not correlated with the learning curve. In addition, mean time to cecal intubation decreased significantly, from 11.16 to 8.39 minutes, after 150 procedures. Logistic regression analysis found that prolonged cecal intubation was caused by the following factors: elderly patients, female sex, low body mass index, poor bowel preparation, poor American Society of Anesthesiologists status, abdominal pain as an indication, instructors supervision, and low case volume. LIMITATIONS We did not record final pathologic reports of detected polyps and withdrawal time. CONCLUSIONS Competence in technically efficient screening and diagnostic colonoscopy generally requires experience with more than 150 cases. Also, factors associated with prolonged cecal intubation for typical trainees did not differ from those for experienced colonoscopists.

Intraductal balloon-guided direct peroral cholangioscopy with an ultraslim upper endoscope (with videos)

BACKGROUND Peroral cholangioscopy (POC) provides direct visualization of the bile duct and facilitates diagnostic procedures and therapeutic intervention. The currently available mother-baby endoscope system is not widely used because of several limitations. Although direct cholangioscopy with an ultraslim upper endoscope with a guidewire has been reported, success is not always guaranteed. OBJECTIVE To evaluate the feasibility and success rate of direct POC using an ultraslim endoscope with an intraductal balloon to maintain access compared with the guidewire method. DESIGN Prospective, observational clinical feasibility study. SETTING Tertiary referral center. MAIN OUTCOME MEASUREMENTS We compared overall procedure success rates and complications. A successful procedure was defined as one in which the endoscope was advanced into the bifurcation or stenotic segment of the biliary system. PATIENTS AND METHODS Twenty-nine patients with biliary disease underwent direct POC. All patients had previously undergone an endoscopic sphincterotomy or papillary balloon dilation with a large balloon. Eleven patients underwent wire-guided direct POC. Intraductal balloon-guided direct POC was performed in 21 patients. The balloon catheter was used to maintain access while an ultraslim upper endoscope was advanced over the balloon catheter, through the ampulla of Vater, and directly into the bile duct. RESULTS Wire-guided direct POC was successful in 5 of 11 (45.5%) patients. In contrast, the success rate of intraductal balloon-guided direct POC was 95.2% (20/21 patients, P < .05). Forceps biopsies under direct visualization of the intraductal lesion and therapeutic intervention, including laser lithotripsy or electrohydraulic lithotripsy, were performed successfully. Procedure-related complications were not observed. LIMITATIONS A small number of patients and no comparison with conventional cholangioscopy. CONCLUSIONS Intraductal balloon-guided direct POC with an ultraslim upper endoscope allows the direct visual examination and therapeutic intervention of bile ducts in patients with biliary disease. Further development of the endoscopic apparatus and specialized accessories are expected to facilitate this procedure.

Direct Peroral Cholangioscopy Using an Ultra-Slim Upper Endoscope for the Treatment of Retained Bile Duct Stones

OBJECTIVES:Intracorporeal lithotripsy must be used under direct visual control with an additional endoscope in order to ensure safety and precise targeting during the removal of difficult-to-extract bile duct stones using conventional methods. The currently available “mother–baby” scope system has several disadvantages. We evaluated the feasibility and efficacy of direct peroral cholangioscopy (POC) using an ultra-slim upper endoscope for electrohydraulic lithotripsy (EHL) or laser lithotripsy (LL) for the treatment of difficult-to-extract bile duct stones.METHODS:A total of 18 patients who were unsuccessfully treated for common bile duct (CBD) stones using conventional endoscopy, including mechanical lithotripsy (ML), underwent EHL or LL under intraductal balloon-guided direct POC using an ultra-slim upper endoscope. The balloon catheter was used to maintain access while an ultra-slim upper endoscope was advanced directly into the bile duct. EHL or LL was performed until it became possible to capture the fragmented stones in a basket. Endoscopic removal of stone fragments by duodenoscopy was attempted in the same session.RESULTS:The overall success rate of bile duct clearance by lithotripsy under direct POC by a single endoscopist was 88.9% (16 of 18). Stone fragmentation under direct POC was successfully performed in nine patients using EHL and in seven patients using LL. The average number of treatment sessions required to complete stone removal was 1.6. ML was performed to complete stone removal in 5 of 18 (27.8%) patients. Procedure-related complications were not observed.CONCLUSIONS:Lithotripsy with EHL or LL under direct POC involving the use of an ultra-slim endoscope by a single endoscopist seems to be an effective and safe treatment for select patients with difficult-to-extract CBD stones.

Impact of patient education with cartoon visual aids on the quality of bowel preparation for colonoscopy

BACKGROUND High-quality bowel preparation is a prerequisite for colonoscopy. Few studies have evaluated visual aids as a means of improving the quality of bowel preparation. OBJECTIVE To assess the effect of patient education by using cartoon visual aids on the quality of bowel preparation. DESIGN An endoscopist-blinded, randomized, controlled trial. SETTING Tertiary referral center. SUBJECTS Patients scheduled for screening colonoscopy in a health examination center. INTERVENTIONS Patients were assigned to receive the existing verbal and written instructions (group A) or a new cartoon visual educational instruction (group B) for colonoscopy. MAIN OUTCOME MEASUREMENTS The primary endpoint was the quality of bowel preparation, assessed by using the Boston Bowel Preparation Scale (BBPS). Secondary endpoints were the quality of bowel preparation assessed by using the Universal Preparation Assessment Scale; insertion, withdrawal, and workup times; and polyp detection rates in the 2 groups. Logistic regression analysis was performed to determine the factors associated with poor bowel preparation according to a BBPS score less than 5. RESULTS Group B exhibited better bowel preparation than group A according to BBPS scores (mean BBPS score, 6.12 ± 2.19 vs 7.44 ± 1.87, P ≤ .01; median BBPS score, 6.00 ± 0.00 vs 9.00 ± 0.00, P ≤ .01; good bowel preparation for colonoscopy, BBPS score ≥5, 81.6% vs 93.1%, P = .02). Multivariate analysis revealed that older age (odds ratio 1.07, P ≤ .01) and no use of visual aids (odds ratio 3.08, P = .02) were independent factors associated with poor bowel preparation. LIMITATIONS Single-center study. CONCLUSIONS Patient education with cartoons effectively improved bowel preparation for colonoscopy.

Combined endoscopic stent-in-stent placement for malignant biliary and duodenal obstruction by using a new duodenal metal stent (with videos)

BACKGROUND Self-expandable metal stents (SEMSs) are an effective palliative treatment for malignant biliary or duodenal strictures, but endoscopic stenting for combined malignant biliary and duodenal obstruction remains technically difficult. OBJECTIVE To evaluate the feasibility and clinical success rate of endoscopic double stent-in-stent placement by using a new duodenal metallic stent for the management of malignant biliary and duodenal obstructions. DESIGN Prospective, observational clinical feasibility study. SETTING Tertiary referral center. MAIN OUTCOME MEASUREMENT Technical and clinical success, complications, midterm outcome. PATIENTS AND METHODS Eight patients with inoperable malignant biliary and duodenal strictures were enrolled. Endoscopic placement of a biliary SEMS was performed through the mesh of the duodenal stent. RESULTS The duodenal strictures were in the first part of the duodenum in 3 patients (type 1) and in the second part in 5 patients (type 2). Duodenal stents were successfully deployed in all patients. Endoscopic placement of a biliary SEMS through the mesh of the duodenal stent was successful in 7 (87.5%) of 8 patients. In 2 of 3 patients with type 2 duodenal strictures with failed bile duct cannulation, biliary stenting was successful by using the rendezvous procedure. Early complications occurred in 1 patient. The overall median survival after combined stenting was 91 days (range 36-314 days). LIMITATIONS Small number of patients and no comparison with other enteral stents. CONCLUSIONS Biliary stenting through the new duodenal metallic stent is technically feasible and has a high success rate. Combined endoscopic biliary and duodenal stent-in-stent placement is a promising solution for the palliation of malignant biliary and duodenal obstruction.

Long-Term Efficacy of Endoscopic Submucosal Dissection Compared with Surgery for Early Gastric Cancer: A Retrospective Cohort Study

Background/Aims This study aimed to compare the outcomes of endoscopic submucosal dissection (ESD) and gastrectomy based on the two sets of indications for ESD, namely guideline criteria (GC) and expanded criteria (EC). Methods Between January 2004 and July 2007, 213 early gastric cancer (EGC) patients were enrolled in this study. Of these patients, 142 underwent ESD, and 71 underwent gastrectomy. We evaluated the clinical outcomes of these patients according to the criteria. Results The complication rates in the ESD and gastrectomy groups were 8.5% and 28.2%, respectively. The duration of hospital stay was significantly shorter in the ESD group than the gastrectomy group according to the GC and EC (p<0.001 and p<0.001, respectively). There was no recurrence in the ESD and gastrectomy groups according to the GC, and the recurrence rates in the ESD and gastrectomy groups were 4.7% and 0.0% according to the EC, respectively (p=0.279). The occurrence rates of metachronous cancer in the ESD and gastrectomy groups were 5.7% and 5.0% according to the GC (p=1.000) and 7.5% and 0.0% according to the EC (p=0.055), respectively. Conclusions Based on safety, duration of hospital stay, and long-term outcomes, ESD may be an effective and safe first-line treatment for EGC according to the EC and GC.

Comparison of a newly designed double-layered combination covered stent and D-weave uncovered stent for decompression of obstructive colorectal cancer: a prospective multicenter study.

PURPOSE: Stent reocclusion and migration are the most important complications after stent insertion. To overcome both problems, a double-layered combination covered stent was developed. Our purpose was to compare the efficacy and safety of the newly designed double-layered combination covered stent (Niti-S enteral colonic stent, Comvi type) and the double-wire woven uncovered stent (Niti-S enteral colonic stent, D-type) in the treatment of malignant colorectal obstructions. METHODS: Sixty-eight patients with obstructive colorectal cancer underwent stent placement for preoperative decompression (n = 30) or palliative purpose (n = 38) at 6 medical centers. Combination covered stents were used in 31 patients and uncovered stents were used in 37 patients. RESULTS: There were no significant differences between both stents in terms of technical and clinical success rates. Regarding complications after stent insertion, there was no significant difference in early stent occlusion and migration rate between the combination covered stents and the uncovered stents. Despite a trend toward lower rates of late stent occlusion in the combination covered stent group, there was no significant difference in the rate of late stent occlusion by tumor ingrowth between the 2 groups (0% vs 20%, respectively; P = .107), and late stent migration occurred significantly more often with the combination covered stent (22.2% vs 0%, respectively; P = .041). However, we observed no significant difference in the overall late-complication rates and stent patency duration between the 2 groups. CONCLUSIONS: In our study, we could not prove that the newly designed double-layered combination covered stents have preventive advantages in stent migration compared with the uncovered stent.

Clinical feasibility of direct peroral cholangioscopy–guided photodynamic therapy for inoperable cholangiocarcinoma performed by using an ultra-slim upper endoscope (with videos)

BACKGROUND Photodynamic therapy (PDT) has emerged as a promising palliative treatment for inoperable cholangiocarcinoma. Cholangioscopy-guided PDT can be useful for identification of tumor margins, determination of the appropriate location for placement of the diffuser, and evaluation of the patients response to therapy. OBJECTIVE To evaluate the feasibility of PDT under direct peroral cholangioscopy (POC) by using an ultra-slim upper endoscope in patients with inoperable cholangiocarcinoma. DESIGN Prospective, observational, pilot study. SETTING Single tertiary-care referral center. PATIENTS This study involved 9 patients with inoperable extrahepatic cholangiocarcinoma. INTERVENTION Photofrin II was administered intravenously 48 hours before PDT. Additional PDT was performed up to 48 hours after the initial application of therapy. A successful direct POC-guided PDT was defined as advancement of the endoscope into the distal margin of the tumor and maintenance of endoscope position until PDT was completed. MAIN OUTCOME MEASUREMENTS The clinical feasibility, usefulness, and complications of direct POC for PDT. RESULTS Seventeen sessions of direct POC for PDT were performed in 9 patients. PDT was performed successfully in 15 of 17 sessions (88.2%) and 7 of 9 patients (77.8%). Biliary drainage under direct POC, if necessary after PDT, was possible in 100% of patients (7/7). Follow-up direct POC confirmed significant tumor ablation after PDT in 5 patients. One patient reported mild skin redness; no major procedure-related complications were observed. LIMITATIONS Small sample size, pilot study. CONCLUSION Direct POC-guided PDT by using an ultra-slim upper endoscope seems to be both feasible and safe in select patients with inoperable extrahepatic cholangiocarcinoma.

A prospective randomized comparative study of cold forceps polypectomy by using narrow-band imaging endoscopy versus cold snare polypectomy in patients with diminutive colorectal polyps

BACKGROUND AND AIMS A previous study reported that cold snare polypectomy (CSP) was superior to cold forceps polypectomy (CFP) for the removal of diminutive colorectal polyps (DCPs) (≤5 mm) when the techniques were assessed for completeness of resection. However, completeness is expected to be greater with CFP when strict investigation of the remnant polyp is performed. The aim of this study was to assess the efficacy of CFP with narrow-band imaging (NBI) evaluation of polypectomy sites for removal of DCPs, compared with CSP. METHODS This was a randomized, controlled, noninferiority trial at a tertiary-care referral hospital. Of the 380 patients screened, 146 patients with 231 DCPs were enrolled. CFP was used to resect DCPs until no remnant polyp was visible by NBI endoscopy. The primary noninferiority endpoint was histologic eradication of polyps, with a noninferiority margin of -10%. RESULTS A size of >3 mm was seen in 129 polyps (55.8%). The overall rates of histologic eradication were 90.5% in the CFP group and 93.0% in the CSP group (difference, 2.5%; 95% confidence interval [CI], -9.67 to 4.62). However, when confined to the polyps >3 mm, the histologic eradication rate was 86.8% and 93.4% (95% CI, -17.2 to 3.6), respectively. Polyp size, histology, location, and time taken for polypectomy did not differ between the groups. The failure rate of tissue retrieval was higher in the CSP than in the CFP group (7.8% vs 0.0%, respectively; P =.001). CONCLUSIONS In this study, >90% of all DCPs were completely resected by using CFP with NBI evaluation of polypectomy sites, showing noninferiority compared with CSP. However, in polyps measuring >3 mm, CFP failed to show noninferiority versus CSP. CFP appears to be the proper method for resection of DCPs 1 to 3 mm in size if no remnant polyp is visible by NBI endoscopy, but CFP is likely to be insufficient for larger polyps. ( CLINICAL TRIAL REGISTRATION NUMBER NCT02201147.).

Effectiveness of sodium alginate as a submucosal injection material for endoscopic mucosal resection in animal.

BACKGROUND/AIMS Although various solutions are being tested for submucosal injection during endoscopic resection, ideal solution has not been established yet. We performed an animal study to evaluate the possibility of sodium alginate as an ideal submucosal injection solution for endoscopic mucosal resection (EMR). METHODS To compare the lesion-lifting properties of different solutions, injection was done to the submucosal layer of porcine stomach. Then the height of mucosal elevation was measured. In addition, EMR was performed after submucosal injection of sodium alginate solution in six dogs. Two were euthanized after 30 minutes of endoscopic observation while the others were euthanized after 1-4 weeks. Retrieved stomachs were examined microscopically. RESULTS Sodium alginate and sodium hyaluronate solutions maintained longer elevation of the submucosal layer than other solutions. There was no significant difference in the height between two solutions. A clear separation of the mucosal layer from the proper muscle layer was achieved by injecting sodium alginate solution. Histological examination of EMR-induced artificial ulcers revealed no apparent tissue damage and showed normal healing process. CONCLUSIONS Sodium alginate solution creates a sufficient submucosal fluid cushion without apparent tissue damage. It can be considered as an effective submucosal injection material.