Takuji Kawamura

Clinical evaluation of a newly developed single-balloon enteroscope

BACKGROUND Double-balloon enteroscopy (DBE) is a useful and epoch-making technique for small-bowel diseases. The single-balloon enteroscope (SBE) is a new instrument introduced by Olympus. OBJECTIVE To evaluate a prototype of the SBE. DESIGN A prospective case series. SETTING Kyoto Second Red Cross Hospital, between April 2006 and July 2007. PATIENTS We used the SBE system to perform 37 enteroscopic examinations on 27 patients, including 22 oral and 15 anal approaches. MAIN OUTCOME MEASUREMENTS The rate of whole small-bowel visualization, mean time necessary for the investigation, discovery rate of lesions, and complications. RESULTS We observed the entire small intestine in 1 of 8 cases (12.5%) that we examined. The mean (+/-SD) time necessary for the oral approach was 83 +/- 38 minutes and that for the anal approach was 90 +/- 32 minutes. The preparation time was less than 5 minutes in both approaches. Small-intestinal lesions were detected in 11 of the 27 patients (40.7%). Perforation occurred in one case as a complication, but the injury healed without surgical intervention. LIMITATION This was a single-center study. CONCLUSIONS Use of the SBE system in the endoscopic study of the small intestine makes it possible to observe the entire small intestine and to diagnose lesions; thus, the SBE system is a useful instrument for small-bowel diseases. However, the rate of whole small-bowel visualization was inferior to the DBE system.

Next-generation narrow band imaging system for colonic polyp detection: a prospective multicenter randomized trial

PurposePrevious studies have yielded conflicting results on the colonic polyp detection rate with narrow-band imaging (NBI) compared with white-light imaging (WLI). We compared the mean number of colonic polyps detected per patient for NBI versus WLI using a next-generation NBI system (EVIS LUCERA ELITE; Olympus Medical Systems) used with standard-definition (SD) colonoscopy and wide-angle (WA) colonoscopy.MethodsDesign: this study is a 2 × 2 factorial, prospective, multicenter randomized controlled trial. Setting: this study was conducted at five academic centers in Japan. Interventions: patients were allocated to one of four groups: (1) WLI with SD colonoscopy (H260AZI), (2) NBI with SD colonoscopy (H260AZI), (3) WLI with WA colonoscopy (CF-HQ290), and (4) NBI with WA colonoscopy (CF-HQ290). Main outcome: the mean numbers of polyps detected per patient were compared between the four groups: WLI with/without WA colonoscopy and NBI with/without WA colonoscopy.ResultsOf the 454 patients recruited, 431 patients were enrolled. The total numbers of polyps detected by WLI with SD, NBI with SD, WLI with WA, and NBI with WA were 164, 176, 188, and 241, respectively. The mean number of polyps detected per patient was significantly higher in the NBI group than in the WLI group (2.01 vs 1.56; P = 0.032). The rate was not higher in the WA group than in the SD group (1.97 vs 1.61; P = 0.089).ConclusionsAlthough WA colonoscopy did not improve the polyp detection, next-generation NBI colonoscopy represents a significant improvement in the detection of colonic polyps.

Does Single-Balloon Enteroscopy Contribute to Successful Endoscopic Retrograde Cholangiopancreatography in Patients with Surgically Altered Gastrointestinal Anatomy?

Background. Balloon-assisted enteroscopy has been recognized as a useful method for performing endoscopic retrograde cholangiopancreatography in patients with complex postsurgical anatomy. Objective. To clarify the usefulness of single-balloon enteroscopy for performing endoscopic retrograde cholangiopancreatography successfully in patients after Billroth II gastrectomy or Roux-en-Y reconstruction and compare it with that of conventional endoscopy. Patients and Methods. We analyzed 204 endoscopic retrograde cholangiopancreatography procedures performed at Kyoto Second Red Cross Hospital between 1997 and 2011 in 93 patients after Billroth II gastrectomy and Roux-en-Y reconstruction with gastrectomy and choledochojejunostomy. We compared recent results with those achieved before the advent of single-balloon enteroscopy (“pre-single-balloon enteroscopy” group versus “post-single-balloon enteroscopy” group). Results. The rate of reaching the blind end was 11/12 (91.7%) in post-single-balloon enteroscopy Roux-en-Y gastrectomy cases and 3/9 (33.3%) in pre-single-balloon enteroscopy Roux-en-Y gastrectomy cases (P = 0.015). The rate of accomplishing target procedures was 7/12 (58.3%) in post-single-balloon enteroscopy Roux-en-Y gastrectomy cases. No significant difference was found in the rates for Billroth II gastrectomy cases. Conclusion. The single-balloon enteroscopy system is effective in reaching the blind end in patients who have undergone Roux-en-Y reconstruction; however, further innovations are needed to accomplish endoscopic retrograde cholangiopancreatography-related procedures.

Improved visibility of colorectal flat tumors using image-enhanced endoscopy.

Colonoscopy is considered the gold standard for detecting colorectal tumors; however, conventional colonoscopy can miss flat tumors. We aimed to determine whether visualization of colorectal flat lesions was improved by autofluorescence imaging and narrow‐band imaging image analysis in conjunction with a new endoscopy system. Eight physicians compared autofluorescent, narrow‐band, and chromoendoscopy images to 30 corresponding white‐light images of flat tumors. Physicians rated tumor visibility from each image set as follows: +2 (improved), +1 (somewhat improved), 0 (equivalent to white light), −1 (somewhat decreased), and −2 (decreased). The eight scores for each image were totalled and evaluated. Interobserver agreement was also examined. Autofluorescent, narrow‐band, and chromoendoscopy images showed improvements of 63.3% (19/30), 6.7% (2/30), and 73.3% (22/30), respectively, with no instances of decreased visibility. Autofluorescence scores were generally greater than narrow‐band scores. Interobserver agreement was 0.65 for autofluorescence, 0.80 for narrow‐band imaging, and 0.70 for chromoendoscopy. In conclusion, using a new endoscopy system in conjunction with autofluorescent imaging improved visibility of colorectal flat tumors, equivalent to the visibility achieved using chromoendoscopy.

Clinical usefulness of a short‐type, prototype single‐balloon enteroscope for endoscopic retrograde cholangiopancreatography in patients with altered gastrointestinal anatomy: Preliminary experiences

A limited number of endoscopic retrograde cholangiopancreatography (ERCP) accessories are compatible with the conventional single‐balloon enteroscope (SBE) because of the latters dimensions. The aim of the present study was to assess the utility of a prototype SBE that has a shorter working length and a wider channel than the conventional SBE.

A comparison of the resection rate for cold and hot snare polypectomy for 4–9 mm colorectal polyps: a multicentre randomised controlled trial (CRESCENT study)

Objective To investigate the success rate of cold snare polypectomy (CSP) for complete resection of 4–9 mm colorectal adenomatous polyps compared with that of hot snare polypectomy (HSP). Design A prospective, multicentre, randomised controlled, parallel, non-inferiority trial conducted in 12 Japanese endoscopy units. Endoscopically diagnosed sessile adenomatous polyps, 4–9 mm in size, were randomly assigned to the CSP or HSP group. After complete removal of the polyp using the allocated technique, biopsy specimens from the resection margin after polypectomy were obtained. The primary endpoint was the complete resection rate, defined as no evidence of adenomatous tissue in the biopsied specimens, among all pathologically confirmed adenomatous polyps. Results A total of 796 eligible polyps were detected in 538 of 912 patients screened for eligibility between September 2015 and August 2016. The complete resection rate for CSP was 98.2% compared with 97.4% for HSP. The non-inferiority of CSP for complete resection compared with HSP was confirmed by the +0.8% (90% CI −1.0 to 2.7) complete resection rate (non-inferiority p<0.0001). Postoperative bleeding requiring endoscopic haemostasis occurred only in the HSP group (0.5%, 2 of 402 polyps). Conclusions The complete resection rate for CSP is not inferior to that for HSP. CSP can be one of the standard techniques for 4–9 mm colorectal polyps. (Study registration: UMIN000018328)

CURRENT STATUS OF ENDOSCOPIC MANAGEMENT FOR NONVARICEAL UPPER GASTROINTESTINAL BLEEDING

Endoscopic hemostasis is widely performed for nonvariceal upper gastrointestinal (UGI) bleeding. As the aged Japanese population rapidly increases, the number of patients experiencing complications increases. The aim of this study was to evaluate the recent results of endoscopic hemostasis for nonvariceal UGI bleeding. A retrospective analysis of patients who underwent endoscopic procedures for nonvariceal UGI bleeding was performed. We performed 223 endoscopic procedures on 217 patients between January 1995 and July 2000, and 238 endoscopic procedures on 236 patients between January 2006 and September 2009 at the Kyoto Second Red Cross Hospital. We divided the patients into the 1995–2000 group and the 2006–2009 group. Patient characteristics, hemostasis methods chosen, rates of temporary hemostasis and rebleeding, and mortality were analyzed. There were many serious and actively bleeding cases in the 2006–2009 group (P < 0.001). The endoclip method and intravenous proton pump inhibitor were mainly used in the 2006–2009 group compared with the drug‐injection method and intravenous H2 receptor antagonist in the 1995–2000 group (P < 0.001). Through these treatments, the two groups were able to obtain similar treatment outcomes. Through the progress of endoscopic management we obtained similar satisfactory results in the 2006–2009 group, which had multiple complicated cases, compared to the 1995–2000 group.

Current status of single-balloon enteroscopy: Insertability and clinical applications.

The single-balloon enteroscopy (SBE) system was launched in 2007, proposed as a simpler method than double-balloon enteroscopy (DBE). Controversy surrounds whether the SBE system has the same insertability as DBE. However, many methods have been proposed to improve the depth of insertion with the SBE system, involving several techniques and endoscopic accessories. SBE is used for investigating not only small bowel diseases, but also diseases of the pancreatobiliary and colonic structures. SBE is a necessary advancement for many endoscopic procedures and applications in modern clinical practice. In our review, we summarized the current literature concerning the insertability of SBE and described the technical aspects of improving the rate of deep insertion in SBE procedures. In addition, the recent applications of SBE to diseases besides those of the small bowel are described.

Examination time as a quality indicator of screening upper gastrointestinal endoscopy for asymptomatic examinees

The significance of examination time of esophagogastroduodenoscopy (EGD) for asymptomatic examinees is yet to be established. We aimed to clarify whether endoscopists who allot more examination time can detect higher numbers of neoplastic lesions among asymptomatic examinees.

Morphological Characteristics and Location of Missed, Advanced Colorectal Neoplasms after Colonoscopy

This retrospective study aimed to clarify the clinical characteristics of advanced colorectal neoplasms after colonoscopy, likely to have been missed on the previous colonoscopy. We reviewed a total of 5,768 consecutive colonoscopies performed from April 2010 to September 2013 in 4,841 patients, and analyzed advanced colorectal neoplasms after colonoscopy, particularly focusing on their morphological characteristics and locations, as compared with primary lesions, defined as lesions detected in their first colonoscopy or in a subsequent colonoscopy >5 years after the previous one. Of the 5,768 examinations, 922 advanced neoplasms (including 217 cancers with ≥T2) were detected, and 167 lesions (18.1%) were diagnosed within 5 years after a previous colonoscopy (post-colonoscopy advanced neoplasms). The incidence of right-sided lesions in the post-colonoscopy advanced neoplasms (48.5%, 81/167) was significantly higher than in the primary lesions (34.0%, 257/755; p <0.001). We excluded 217 cancers with ≥T2 from the morphological analysis to characterize early-stage post-colonoscopy advanced neoplasms. The incidence of non-polypoid lesions in the post-colonoscopy advanced neoplasms (25.6%, 41/160) was significantly higher than that in the primary lesions (12.3%, 67/545; p <0.001). These findings suggest that extra attention should be paid to non-polypoid, right-sided advanced colorectal neoplasms during screening and surveillance colonoscopy. J. Med. Invest. 63: 163-170, August, 2016.