Retroview colonoscopy

Safety, Feasibility, and Efficacy of Pancolonic Retroflexed Viewing Using a Short-turn Radius Colonoscope

GOALS

The goal of this study was to evaluate the safety and feasibility of routine segmental retroflexed withdrawal viewing (RV) of the colon with the RetroView colonoscope.

MATERIALS AND METHODS

This was a prospective, single-center, 2-stage diagnostic trial. After cecal intubation, mucosal evaluation by forward viewing (FV) and RV was performed by segment (right, transverse, left, and sigmoid colon, and rectum). Lesions detected during FV were removed and/or marked before retroflexion. Safety and feasibility were measured through adverse event and technical success rates. All lesions detected and removed endoscopically were recorded.

RESULTS

Two hundred twenty-five patients underwent colonoscopy with the RetroView colonoscope. Retroflexion by segment was successful in the right, transverse, left, and sigmoid colon, and rectum in 98.9%, 100%, 100%, 82.6%, and 100% of cases, respectively. The mean total procedure time was 16.6 minutes. Ninety-four lesions were detected through retroflexion evaluation, for an increase in the lesions' detection rate of 30.7%. The per-adenoma miss rate of standard colonoscopy (FV) was 35.71%. The adenoma detection rate (ADR) for FV was 16%, whereas, when performing FV and RV, the ADR increased to 24.9%. Adverse events were recorded in 0.4% of cases. Therapeutic procedures were performed successfully through the retroflexed position in 81/225 patients.

CONCLUSIONS

Routine retroflexion evaluation of the colonic mucosa by segment using the RetroView colonoscope is safe and feasible. Retroflexion evaluation increases the detection rate of colonic lesions behind folds, including the number of adenomas per colonoscopy and ADR, offering a complete screening colonoscopy. All therapeutic procedures are feasible through retroflexion.

Quantitative assessment of the effect of position changes during colonoscopy withdrawal

OBJECTIVE

Although trials assessing the effectiveness of position changes during colonoscopy withdrawal have been reported, there has been no agreement whether such position changes actually improve the polyp detection rate (PDR) or adenoma detection rate (ADR). This article aimed to address this issue by performing a systematic review.

METHODS

Relevant studies from databases including PubMed, EMBASE and the Cochrane Library and Science Citation Index were retrieved. Two reviewers independently identified potentially relevant studies. Outcome measures were PDR, ADR and bowel distention.

RESULTS

Eight studies were included, of which seven were randomized controlled trials (RCTs). A non-randomized controlled trial and all four cross-over RCTs reported significant improvement in PDR, ADR and bowel distention with position change during colonoscopic withdrawal, while three parallel-group RCTs did not confirm its effectiveness.

CONCLUSIONS

The conflicting results of high-quality trials indicate that the effectiveness of position change during colonoscopy withdrawal on PDR, ADR and bowel distension is uncertain. Thus, position change during colonoscopy withdrawal should not be routinely applied until future studies demonstrate its efficacy.

Usefulness of oil lubrication during colonoscopy: A comparative study with the conventional technique

BACKGROUND

The different forms of lubrication are among the most simple, accessible, and economic techniques that have been implemented for improving the diagnostic performance of colonoscopy.

AIM

To determine whether the use of oil improved the number of complete colonoscopies, facilitated the procedure, reduced pain, or improved the study's diagnostic performance, compared with the conventional lubrication technique.

PATIENTS AND METHODS

One hundred and seventy-five patients referred for colonoscopy were alternately allocated to receive treatment with the standard lubrication method with chlorhexidine gel (group 1) or lubrication with corn oil administered through the working channel (group II). The number of complete colonoscopies, the length of time needed to reach the cecum, the degree of difficulty estimated by the endoscopist and the assistant, the level of pain at the end of the study estimated by the patient, and the endoscopic findings were all determined.

RESULTS

Eighty-eight patients made up group I and 87 made up group II. No statistically significant differences were found between the two groups in relation to general characteristics, the number of complete colonoscopies (93 vs. 97%, respectively), the time needed to reach the cecum (8:00 vs. 8:41min, respectively), the level of pain at the end of the study, or the detection of polyps. The degree of difficulty was slightly lower in group II, but with no statistical significance.

CONCLUSIONS

Lubrication with oil during colonoscopy did not improve the number of complete colonoscopies, did not facilitate the study, nor did it reduce pain or increase the diagnostic performance of the study, when compared with the conventional technique.

[Factors influencing the miss rate of polyps in a tandem colonoscopy study]

BACKGROUND/AIMS

The miss rate of colon polyps and its related factors have not been clearly identified yet. This study aims to review the miss rate of polyps both on the patient-level and on the polyp-level and to analyze the factors affecting the miss rate such as those related to the endoscopist, procedure, patient, and polyp.

METHODS

From August 2011 to August 2013, patients who underwent elective second colonoscopy for resection of polyps, the sizes of which were not small enough to be resected by biopsy forceps alone at first colonoscopy, were enrolled retrospectively.

RESULTS

The miss rate on the patient-level was 59.2% (234/395) and on the polyp-level was 27.9% (578/2,068). There was no significant difference in the miss rate depending on the experience of the endoscopists or characteristics of the patients. In terms of the procedure, the miss rate was higher when the colonoscopy was performed in the afternoon (OR 1.632, p=0.046). It was found that the miss rate of polyps increased when the polyps were small (OR 4.595, p<0.001 in <5 mm/OR 3.447, p<0.001 in 5-10 mm), flat or sessile (OR 2.406, p<0.001 in flat/OR 1.768, p=0.002 in sessile), and located in the left colon (OR 1.391, p=0.007).

CONCLUSIONS

The experience of endoscopists did not have influence on the accuracy of polyp detection. However, the fatigue of endoscopists in the afternoon is considered to render polyp detection less accurate. Also, the large curves and folds of the sigmoid colon are regarded as a reason for the higher miss rate of polyps in the left colon.

Impact of retroflexion vs. second forward view examination of the right colon on adenoma detection: a comparison study

OBJECTIVES

Although screening colonoscopy is effective in preventing distal colon cancers, effectiveness in preventing right-sided colon cancers is less clear. Previous studies have reported that retroflexion in the right colon improves adenoma detection. We aimed to determine whether a second withdrawal from the right colon in retroflexion vs. forward view alone leads to the detection of additional adenomas.

METHODS

Patients undergoing screening or surveillance colonoscopy were invited to participate in a parallel, randomized, controlled trial at two centers. After cecal intubation, the colonoscope was withdrawn to the hepatic flexure, all visualized polyps removed, and endoscopist confidence recorded on a 5-point Likert scale. Patients were randomized to a second exam of the proximal colon in forward (FV) or retroflexion view (RV), and adenoma detection rates (ADRs) compared. Logistic regression analysis was used to evaluate predictors of identifying adenomas on the second withdrawal from the proximal colon.

RESULTS

A total of 850 patients (mean age 59.1±8.3 years, 59% female) were randomly assigned to FV (N=400) or RV (N=450). Retroflexion was successful in 93.5%. The ADR (46% FV and 47% RV) and numbers of adenomas per patient (0.9±1.4 FV and 1.1±2.1 RV) were similar (P=0.75 for both). At least one additional adenoma was detected on second withdrawal in similar proportions (10.5% FV and 7.5% RV, P=0.13). Predictors of identifying adenomas on the second withdrawal included older age (odds ratio (OR)=1.04, 95% confidence interval (CI)=1.01-1.08), adenomas seen on initial withdrawal (OR=2.8, 95% CI=1.7-4.7), and low endoscopist confidence in quality of first examination of the right colon (OR=4.8, 95% CI=1.9-12.1). There were no adverse events.

CONCLUSIONS

Retroflexion in the right colon can be safely achieved in the majority of patients undergoing colonoscopy for colorectal cancer screening. Reexamination of the right colon in either retroflexed or forward view yielded similar, incremental ADRs. A second exam of the right colon should be strongly considered in patients who have adenomas discovered in the right colon, particularly when endoscopist confidence in the quality of initial examination is low.

How can screening colonoscopy be optimized?

Since the implementation of screening programmes, both the incidence and mortality of colorectal cancer have been decreasing. The choice of the preferred screening tool, however, is divergent and the adherence to screening programmes in most countries is still low. Cancer detection tests such as the guaiac faecal occult blood test (gFOBT) and the immunohistochemical FOBT (iFOBT) achieve higher acceptance than endoscopy. The sensitivity and specificity of iFOBT are higher than those of gFOBT, but gFOBT is cheaper and easier to perform. Endoscopic screening, which represents cancer prevention tests, has higher sensitivity for premalignant lesions than gFOBT and iFOBT and enables diagnosis and therapy in one single procedure. Since screening colonoscopy and sigmoidoscopy are invasive procedures with potentially severe adverse events, the highest possible quality must be provided. High-tech equipment, experience, training, quality control programmes, excellent bowel preparation and low adverse event rates are pivotal. Alternative screening tools such as CT colonography, barium enema CT and multitarget stool DNA tests have not been established as routine screening tools to date.

The impact of hyoscine-N-butylbromide on adenoma detection during colonoscopy: meta-analysis of randomized, controlled studies

BACKGROUND

Hyoscine-N-butylbromide (HBB) can induce flattening of colon folds through inhibition of smooth muscle activity, which improves mucosal visualization. Whether this affects polyp detection is controversial.

OBJECTIVE

To evaluate whether HBB, administered during colonoscopy, improves polyp and adenoma detection.

DESIGN

We performed a comprehensive search in MEDLINE and EMBASE databases to identify randomized, placebo-controlled trials (RCTs) in which HBB was administered during colonoscopy and which also reported the detection rate for polyps and/or adenomas (PDR and/or ADR, respectively).

SETTING

Meta-analysis of 5 RCTs.

PATIENTS

A total of 1998 patients (1006 receiving HBB) were included in the study.

INTERVENTIONS

Intravenous administration of 20 mg (2 mL) HBB or 2 mL saline solution at the time of cecal intubation.

MAIN OUTCOME MEASUREMENTS

The PDR was the primary outcome variable. Secondary outcomes included the ADR, the advanced adenoma detection rate (adv-ADR), and the mean number of polyps and adenomas per patient (PPP and APP, respectively).

RESULTS

The PDR, ADR, and adv-ADR did not differ significantly between the 2 groups. The odds ratios (95% confidence interval [CI]) for PDR, ADR, and adv-ADR were 1.09, 95% CI, 0.91-1.31; 1.13, 95% CI, 0.92-1.38; and 0.9, 95% CI, 0.63-1.30, respectively. In addition, no significant differences were observed in PPP and APP between the 2 groups.

LIMITATIONS

Small number of studies included. Limited data about secondary outcomes and safety.

CONCLUSION

Our meta-analysis does not provide evidence that routine HBB administration at cecal intubation improves PDR or ADR. More studies are needed for final conclusions, particularly on HBB's effect on PPP and APP.