Wide angle colonoscopy with a prototype instrument: impact on miss rates and efficiency as determined by back-to-back colonoscopies

OBJECTIVE: Polyps are missed during conventional colonoscopy, even with meticulous technique. The aim of this study was to investigate whether a prototype wide angle colonoscope is associated with a reduced miss rate for polyps. METHODS: Two studies were performed. In study 1, a total of 50 patients underwent back-to-back, same-day colonoscopy by a single examiner with the prototype wide angle colonoscope and with a standard colonoscope, with the order of scopes randomized. In study 1, an attempt was made to keep examination time with the two colonoscopes equal. In study 2, a total of 20 patients were examined, 10 by the same colonoscopist who performed study 1 and 10 by a second colonoscopist. In study 2, examiners tried to perform the examinations as quickly as accuracy would allow. RESULTS: In study 1, the miss rate for all polyps was lower with the wide angle colonoscope (20% vs 31%; p = 0.046), although the mean examination time with the wide angle instrument was shorter (6.75 min vs 7.64 min; p = 0.0005). There was no significant difference in detection of adenomas. Polyps, including adenomas, were missed in the peripheral endoscopic field more frequently with the standard colonoscope. In study 2, wide angle colonoscopy was associated with reductions in examination time of 25% and 30% for the two examiners, respectively. Miss rates were the same for one colonoscopist but were higher for the other colonoscopist when the wide angle instrument was used. CONCLUSION: A prototype wide angle colonoscope did not eliminate polyp miss rates. Wide angle colonoscopy has the potential to reduce examination time and improve visualization of the periphery of the endoscopic field of view, but improvements in resolution are needed.     

Impact of bending section length on insertion and retroflexion properties of pediatric and adult colonoscopes

BACKGROUND: Colonoscopes with short bending sections facilitate retroflexion but their effect on other aspects of colonoscope insertion are unknown. We sought to determine the impact of short bending on cecal insertion, terminal ileal intubation, and proximal colon retroflexion. METHODS: Two studies were performed. In study 1, we randomized 104 adult patients with intact colons to undergo colonoscopy with a standard pediatric colonoscope (Olympus PCF-160), a prototype pediatric colonoscope with short bending in four directions (PCF-AYL), or a prototype pediatric colonoscope with short bending in two directions, and normal bending in two directions (PCF-AY3L). In study 2, we randomized 70 patients with intact colons to undergo colonoscopy with a prototype 170 degrees wide angle colonoscope (CFQ160-WL) with a standard bending section length or to a prototype 170 degrees colonoscope with a short bending section (CFQ160-W2L). RESULTS: In study 1, the cecum was reached in all patients. Using the AYL, the cecal intubation time (4.08 min) was significantly longer when compared to both the PCF-160 (2.62 min; p=0.0001) and the AY3L (3.25 min; p=0.02). The AYL required the application of abdominal pressure (79%) and activation of the variable stiffness device (70%) more frequently when compared to both the PCF-160 (32%; p=0.0001 and 41%; p=0.02, respectively) and the AY3L (34%; p=0.0003 and 41%; p=0.02, respectively). Successful cecal retroflexion was possible less often with the PCF-160 (57%) when compared to either the AYL (94%; p=0.005) or AY3L (91%; p=0.001). The ability to intubate the terminal ileum was similar in all three groups (PCF-160 and AY3L 100%; AYL 94%) as was the time needed to intubate (p=0.73). Depth of ti intubation was deeper for the PCF-160 when compared to the AYL (p=0.0002) or AY3L (p=0.02). There was a trend toward deeper ileal intubation with the AY3L compared to AYL (p=0.09). In study 2, no difference was noted in cecal intubation time (p=0.1) or in frequency of application of abdominal pressure (p=0.28), position change (p=0.15), or activation of the stiffening device (p=0.46). Cecal retroflexion was successful more often when using the W2L when compared to the WL (p=0.00001). CONCLUSION: Short bending sections facilitate proximal colon retroflexion for both pediatric and adult colonoscopes, but can negatively impact cecal insertion and terminal ileal intubation in pediatric colonoscopes. A pediatric colonoscope with short bending in only two directions had good function for both cecal insertion and proximal colon retroflexion.     

Surface visualization at CT colonography simulated colonoscopy: effect of varying field of view and retrograde view

OBJECTIVES: Colonoscopy is the gold standard for diagnosis of mucosal disease, but has a recognized "miss rate" for polyps probably because some lesions lie in areas of the colonic surface that do not enter the field of view. Using CT colonography (CTC) simulation this pilot study aimed to determine how much colonic surface is visualized with a standard, modern optical colonoscope (field of view 140 degrees ) with or without the addition of a retrograde viewing auxiliary imaging device (RVAID; 135 degrees ) and of a wide-angle (170 degrees ) colonoscope. METHODS: Supine CTC datasets for 20 patients were reviewed with customized CTC software that calculated the percentage of colonic surface seen and number and area of nonvisualized "missed" areas at a unidirectional three-dimensional (3D) endoluminal flythrough, approximating the view obtained at optical colonoscopy. The field of view could be varied from 0-180 degrees . The combination of a colonoscope with RVAID was simulated by an additional flythrough facing the rectum. RESULTS: Mean colonic surface area was 2,743 +/- 759 cm2. Percentage colonic surface visualized at simulated optical colonoscopy with a 90 degrees , 140 degrees , and 170 degrees field of view was 68.0 +/- 5.2%, 86.6 +/- 3.3%, and 92.2 +/- 3.3%, respectively, P < 0.001. Simulation of a 140 degrees colonoscope with an RVAID resulted in almost complete surface visualization, 98.7 +/- 0.5%, with total missed area reduced 10-fold compared with a 170 degrees colonoscope, P < 0.001. CONCLUSION: CTC simulated 140 degrees optical colonoscopy visualizes over 85% of the colonic surface. 170 degrees colonoscopy provides a modest reduction in missed surface and the simulated addition of RVAIDs appears beneficial.     

Does autofluorescence imaging videoendoscopy system improve the colonoscopic polyp detection rate?--a pilot study

OBJECTIVES: Colonoscopy is considered the gold standard for the detection of colorectal polyps; however, polyps can be missed with conventional white light (WL) colonoscopy. The aim of this pilot study was to evaluate whether a newly developed autofluorescence imaging (AFI) system can detect more colorectal polyps than WL.
METHODS: A modified back-to-back colonoscopy using AFI and WL was conducted for 167 patients in the right-sided colon including cecum, ascending and transverse colon by a single experienced colonoscopist. The patient was randomized to undergo the first colonoscopy with either AFI or WL (group A: AFI-WL, group B: WL-AFI). The time needed for both insertion and examination for withdrawal and all lesions detected in the right-sided colon were recorded.
RESULTS: Eighty-three patients were randomized to group A and 84 to group B. The total number of polyps detected by AFI and WL colonoscopy was 100 and 73, respectively. The miss rate for all polyps with AFI (30%) was significantly less than that with WL (49%) ( P = 0.01).
CONCLUSIONS: AFI detects more polyps in the right-sided colon compared to WL colonoscopy.     

Colometer: A real-time quality feedback system for screening colonoscopy

AIM:To investigate the performance of a new software-based colonoscopy quality assessment system.METHODS:The software-based system employs a novel image processing algorithm which detects the levels of image clarity,withdrawal velocity,and level of the bowel preparation in a real-time fashion from live video signal.Threshold levels of image blurriness and the withdrawal velocity below which the visualization could be considered adequate have initially been determined arbitrarily by review of sample colonoscopy videos by two experienced endoscopists.Subsequently,an overall colonoscopy quality rating was computed based on the percentage of the withdrawal time with adequate visualization(scored 1-5;1,when the percentage was 1%-20%;2,when the percentage was 21%-40%,etc.).In order to test the proposed velocity and blurriness thresholds,screening colonoscopy withdrawal videos from a specialized ambulatory colon cancer screening center were collected,automatically processed and rated.Quality ratings on the withdrawal were compared to the insertion in the same patients.Then,3 experienced endoscopists reviewed the collected videos in a blinded fashion and rated the overall quality of each withdrawal(scored 1-5;1,poor;3,average;5,excellent) based on 3 major aspects:image quality,colon preparation,and withdrawal velocity.The automated quality ratings were compared to the averaged endoscopist quality ratings using Spearman correlation coefficient.RESULTS:Fourteen screening colonoscopies were assessed.Adenomatous polyps were detected in 4/14(29%) of the collected colonoscopy video samples.As a proof of concept,the Colometer software rated colonoscope withdrawal as having better visualization than the insertion in the 10 videos which did not have any polyps(average percent time with adequate visualization:79% ± 5% for withdrawal and 50% ± 14% for insertion,P 0.01).Withdrawal times during which no polyps were removed ranged from 4-12 min.The median quality rating from the automated system and the reviewers was 3.45 [interquartile range(IQR),3.1-3.68] and 3.00(IQR,2.33-3.67) respectively for all colonoscopy video samples.The automated rating revealed a strong correlation with the reviewer's rating(ρ coefficient= 0.65,P = 0.01).There was good correlation of the automated overall quality rating and the mean endoscopist withdrawal speed rating(Spearman r coefficient= 0.59,P = 0.03).There was no correlation of automated overall quality rating with mean endoscopists image quality rating(Spearman r coefficient= 0.41,P = 0.15).CONCLUSION:The results from a novel automated real-time colonoscopy quality feedback system strongly agreed with the endoscopists' quality assessments.Further study is required to validate this approach.     

Clinical usefulness of single-balloon endoscopy in patients with previously incomplete colonoscopy

AIM: To evaluate the clinical usefulness of single-balloon endoscopy (SBE) in patients in whom a colonoscope was technically difficult to insert previously.METHODS: The study group comprised 15 patients (8 men and 7 women) who underwent SBE for colonoscopy (30 sessions). The number of SBE sessions was 1 in 7 patients, 2 in 5 patients, 3 in 1 patient, 4 in 1 patient, and 6 in 1 patient. In all patients, total colonoscopy was previously unsuccessful. The reasons for difficulty in scope passage were an elongated colon in 6 patients, severe intestinal adhesions after open surgery in 4, an elongated colon and severe intestinal adhesions in 2, a left inguinal hernia in 2, and multiple diverticulosis of the sigmoid colon in 1. Three endoscopists were responsible for SBE. The technique for inserting SBE in the colon was basically similar to that in the small intestine. The effectiveness of SBE was assessed on the basis of the success rate of total colonoscopy and the presence or absence of complications. We also evaluated the diagnostic and treatment outcomes of colonoscopic examinations with SBE.RESULTS: Total colonoscopy was successfully accomplished in all sessions. The mean insertion time to the cecum was 22.9 ± 8.9 min (range 9 to 40). Abnormalities were found during 21 sessions of SBE. The most common abnormality was colorectal polyps (20 sessions), followed by radiation colitis (3 sessions) and diverticular disease of the colon (3 sessions). Colorectal polyps were resected endoscopically in 15 sessions. A total of 42 polyps were resected endoscopically, using snare polypectomy in 32 lesions, hot biopsy in 7 lesions, and endoscopic mucosal resection in 3 lesions. Fifty-six colorectal polyps were newly diagnosed on colonoscopic examination with SBE. Histopathologically, these lesions included 2 intramucosal cancers, 42 tubular adenomas, and 2 tubulovillous adenomas. The mean examination time was 48.2 ± 20.0 min (range 25 to 90). Colonoscopic examination or endoscopic treatment with SBE was not associated with any serious complications.CONCLUSION: SBE is a useful and safe procedure in patients in whom a colonoscope is technically difficult to insert.     

Clinical application of a new colonoscope with variable insertion tube rigidity: a pilot study

BACKGROUND: Colonic loop formation can prolong colonoscopy, increase patient discomfort, and preclude complete examination. A colonoscope with variable insertion tube rigidity may facilitate colonoscopy. Our aim was to determine whether the use of a colonoscope with variable insertion tube rigidity reduces insertion time and improves patient acceptance of colonoscopy. METHODS: Fifty patients were randomly assigned to undergo colonoscopy with a conventional colonoscope or a variable rigidity colonoscope (VRC). Patient acceptance, dosage of medication, use of abdominal pressure, and patient repositioning were assessed. Statistical analysis was performed by the 2-sample Wilcoxon rank sum test and an extension of Fisher exact test. RESULTS: The groups were comparable with respect to age, gender, and medications required during colonoscopy. The cecum was reached in all 25 patients who underwent colonoscopy with the VRC, including 1 patient in whom the cecum was not reached at a previous colonoscopy with a conventional instrument. In the conventional colonoscopy group, the cecum was not reached in 4 patients (2 poor preparation, 2 loop formation). There was no significant difference between the 2 groups with respect to insertion time. In the group that underwent colonoscopy with the variable rigidity instrument, less abdominal pressure was required (p = 0.05), and nursing assessment of patient discomfort was more favorable (p = 0.05). There were no complications and no significant differences in the intubation time to cecum or in repositioning, patient acceptance, or patient assessment of abdominal pain. CONCLUSION:The use of a variable rigidity colonoscope reduced the frequency of abdominal pressure but did not affect intubation time to cecum, repositioning, patient acceptance, or patient assessment of abdominal pain.     

Usefulness of a pediatric colonoscope for colonoscopy in adults

BACKGROUND: There are few published data on how different types of colonoscopes affect success in reaching the cecum and patient comfort. We examined the feasibility of using a pediatric colonoscope for routine colonoscopy in adults and investigated whether there were subgroups of patients in whom use of this instrument was preferable. METHODS: One-hundred fifty adults undergoing outpatient colonoscopy were randomized to colonoscopy with a standard colonoscope (Olympus CF-100L) or with a pediatric colonoscope (Olympus PCF-100). All procedures were performed by a faculty endoscopist and timed by an independent observer. After examinations, the endoscopist graded procedure difficulty and patients were given a questionnaire that assessed their experience. RESULTS: The adult (n = 77) and pediatric (n = 73) colonoscope groups were comparable in all outcomes measured, including success in reaching the cecum (91% vs. 93%, p = 0.61), mean time to reach the cecum (11.4 vs. 9.7 min, p = 0.07), mean total procedure time (21.8 vs. 21.9 min, p = 0.95), mean meperidine dose (55 vs. 52 mg, p = 0.17); median midazolam dose (2.0 mg in both groups, p = 0.10), the endoscopists' perception of procedure difficulty, and patient comfort scales. Of the 7 patients in whom colonoscopy with the adult colonoscope was unsuccessful, the cecum was reached in 4 by switching to a pediatric colonoscope (all women, 3 of whom had prior hysterectomy). In the 5 patients in whom colonoscopy with the pediatric colonoscope was unsuccessful, the cecum was reached in 1 by switching to an adult colonoscope. Including the cases in which the cecum was reached by switching to the alternative colonoscope, the overall frequency of cecal intubation was 143 of 150 (95%). Subgroup analysis disclosed no difference between the 2 groups in outcomes when gender, presence of diverticulosis, and patient size were considered. Colonoscopy with the pediatric colonoscope was more successful than with the adult instrument in reaching the cecum in women with prior hysterectomy (11 of 12 [92%] vs. 15 of 21 [71%]); however, the numbers in each group were relatively small and the difference was not significant (p = 0.22). CONCLUSIONS: The pediatric colonoscope is suitable for routine colonoscopy in adults. It is also useful in patients in whom colonoscopy with the adult colonoscope is unsuccessful in reaching the cecum (particularly in women). Additional study is needed to see if the pediatric colonoscope is actually superior to the adult colonoscopy for routine colonoscopy in women with prior hysterectomy.     

Comparison of Pentax HiLine and Olympus Lucera systems at screening colonoscopy

AIM:To compare the performance characteristics of Pentax HiLine(PHL)(with i-scan) and Olympus Lucera(OL) systems in a screening population.METHODS:Screening colonoscopies in asymptomatic guaiac faecal occult blood test-positive patients with PHL(n = 58) and OL(n = 425) colonoscopes were analysed.All procedures were performed by a single colonoscopist.PHL used white-light endoscopy(WLE) on scope insertion and contrast/surface enhancement(i-scan 1) on withdrawal,and OL utilised WLE both on insertion and withdrawal.Patient age,sex,instrument insertion and withdrawal times,nurse assessed patient comfort scores,midazolam and fentanyl doses,procedure completion and rates of lesion detection were recorded separately for each group.Comparisons between the groups were made using either Fisher’s exact test(for dichotomous variables) or Mann-Whitney U test(for ordinal and continuous variables).RESULTS:Colonoscopy completion rates were similar in both groups:413/425(97.2%) for OL and 55/58(94.9%) for PHL(P = 0.24).For complete colonoscopies,the two groups were well matched for age,sex,colonoscope insertion times(mean 11.1 min in OL vs 11.6 min in PHL,P = 0.93) and normal colonoscopy withdrawal times(mean 15.6 min in OL vs 14.7 min in PHL,P = 0.2).Patients in the PHL group experienced a small increase in discomfort(mean patient comfort scores were 0.49 in the OL and 0.95 in the PHL group,P < 0.0001).While Fentanyl doses required were similar between groups(mean 57.5 μg in OL vs 61.4 μg in PHL,P = 0.13),slightly more Midazolam was required in the PHL group(mean 2.1 mg in OL vs 2.4 mg in PHL,P = 0.035).There was no difference in polyp(58% in OL vs 67% in PHL) or adenoma(49% in OL vs 56% in PHL) detection rates between the groups.Neither the total number of polyps and adenomas,nor the characteristics of these(including size,location or presence of advanced features) were different between the two systems.CONCLUSION:This study suggests that there is no advantage of either colonoscope system in lesion detection.     

Impact of proximal colon retroflexion on adenoma miss rates

BACKGROUND: Small adenomas are commonly missed during routine colonoscopy. The aim of this study was to determine whether routine retroflexion in the proximal colon would improve adenoma detection rates. METHODS: One hundred patients underwent colonoscopy from the cecum to the splenic flexure by a gastroenterology fellow, with the removal of all visualized polyps. The cecum was then reintubated and patients were randomized to a second exam of the proximal colon by an experienced staff physician in either the forward view or a retroflexed view. RESULTS: Two patients were excluded due to a difficult initial cecal intubation. Forty-eight patients were randomized to forward view and 50 patients were randomized to a retroflexed view. Retroflexion was successful in the cecum in 60%, the ascending colon 100%, and the transverse colon 98%. The success in retroflexion was determined in part by the type of colonoscope used. If any portion of the retroflexed examination could not be performed, that reexamination was performed in the forward view. The calculated miss rates for all polyps and adenomas among patients randomized to second examination in the forward view was 36.8% and 33.3%, respectively. The calculated miss rate for all polyps and for adenomas among patients randomized to a second examination in the retroflexed view was 38.1% and 23.7%, respectively. There was no difference in miss rates for all polyps or for adenomas (p= 0.31) when the second examination was performed in the forward view versus retroflexed view. CONCLUSIONS: A second examination by retroflexion in the proximal colon did not increase the calculated miss rate relative to that performed by a forward view examination. These results do not support the addition of routine right colon retroflexion to colonoscopy.     

A randomized controlled trial in a training institution comparing a pediatric variable stiffness colonoscope, a pediatric colonoscope, and an adult colonoscope

BACKGROUND: There are few comparative data on the efficacy of different colonoscopes. This study compared the efficacy of a new pediatric variable stiffness colonoscope with that of standard pediatric and adult colonoscopes in the performance of routine colonoscopy. METHODS: Three hundred sixty-three consecutive patients were randomized to undergo colonoscopy with a pediatric variable stiffness (n = 122), pediatric (n = 114), or adult colonoscope (n = 127). Primary outcomes recorded were minutes to the cecum and completeness of the examination. Secondary outcomes included patient tolerance, use of abdominal compression, and endoscopists' assessment of the difficulty of the procedure. RESULTS: Cecal intubation rates were not statistically different between the groups: variable stiffness (94.3%), pediatric (96.5%), and adult (89.8%) (p = 0.099). There was no significant difference in mean insertion time, patient tolerance, use of abdominal compression, or endoscopists' global assessment or examination difficulty between groups. Overall, the initial completion rate of 93% increased to 97% on switching to a different colonoscope. Colonoscopy was unsuccessful more often and was more time consuming in women who had undergone hysterectomy. CONCLUSION: The variable stiffness colonoscope performs well, but does not appear to offer any distinct advantage over standard pediatric or adult colonoscopes for routine colonoscopy. Further study may identify subgroups of patients that benefit from this new technology.     

Detection of colonic polyps according to insertion/withdrawal phases of colonoscopy

Background and aims  Issues on colonoscopy quality are crucial to reduce the advanced neoplasia miss rate of colonoscopy. Recently, a >6-min withdrawal time has been recommended. However, the relative prevalence of polyp detected during insertion and withdrawal phases of colonoscopy is unknown. Therefore, we designed this prospective, endoscopic study. Materials and methods  Three hundred and sixty-eight patients with 396 adenomas were selected from a consecutive colonoscopic series of 1,205 cases. Detection rates of adenomas, advanced adenomas, and cancer according to withdrawal and insertion phases of colonoscopy, also subgrouping polyps for size and location, were compared. Results  Thirty-two (74%) advanced adenomas and 21 (95%) cancers were detected during the insertion, being only 11 (26%) and one (5%) identified during withdrawal, respectively. This was mainly due to a higher detection of >10 mm polyps during insertion than during withdrawal (75% versus 25%). Conclusions  Most advanced neoplasia are detected during the insertion. Although withdrawal time has been shown to be important, the scope insertion phase related to polyp detection should be specifically addressed.     

Point-of-care, peer-comparator colonoscopy practice audit: The Canadian Association of Gastroenterology Quality Program--Endoscopy

BACKGROUND

Point-of-care practice audits allow documentation of procedural outcomes to support quality improvement in endoscopic practice.

OBJECTIVE

To evaluate a colonoscopists’ practice audit tool that provides point-of-care data collection and peer-comparator feedback.

METHODS

A prospective, observational colonoscopy practice audit was conducted in academic and community endoscopy units for unselected patients undergoing colonoscopy. Anonymized colonoscopist, patient and practice data were collected using touchscreen smart-phones with automated data upload for data analysis and review by participants. The main outcome measures were the following colonoscopy quality indicators: colonoscope insertion and withdrawal times, bowel preparation quality, sedation, immediate complications and polypectomy, and biopsy rates.

RESULTS

Over a span of 16 months, 62 endoscopists reported on 1279 colonoscopy procedures. The mean cecal intubation rate was 94.9% (10th centile 84.2%). The mean withdrawal time was 8.8 min and, for nonpolypectomy colonoscopies, 41.9% of colonoscopists reported a mean withdrawal time of less than 6 min. Polypectomy was performed in 37% of colonoscopies. Independent predictors of polypectomy included the following: endoscopy unit type, patient age, interval since previous colonoscopy, bowel preparation quality, stable inflammatory bowel disease, previous colon polyps and withdrawal time. Withdrawal times of less than 6 min were associated with lower polyp removal rates (mean difference −11.3% [95% CI −2.8% to −19.9%]; P=0.01).

DISCUSSION

Cecal intubation rates exceeded 90% and polypectomy rates exceeded 30%, but withdrawal times were frequently shorter than recommended. There are marked practice variations consistent with previous observations.

CONCLUSION

Real-time, point-of-care practice audits with prompt, confidential access to outcome data provide a basis for targeted educational programs to improve quality in colonoscopy practice.     

Is the variable-stiffness paediatric colonoscope more effective than a standard adult colonoscope for outpatient adult colonoscopy?: A randomised controlled trial

BACKGROUND: Trials with variable-stiffness colonoscopes have yielded conflicting results regarding efficacy and patient tolerance. AIM: We compared a variable-stiffness paediatric colonoscope with a standard adult colonoscope. METHODS: Two hundred and forty consecutive adult outpatients presenting for colonoscopy were randomised to either a variable-stiffness paediatric colonoscope or an adult colonoscope. If there was difficulty in performing colonoscopy with the assigned scope, the endoscopist was given the option of switching to the alternative instrument. In the condition of a severely fixed, angulated sigmoid colon, a final 'salvage' (backup) option was that of switching to an even thinner diameter paediatric colonoscope. RESULTS: The initial frequency of total colonoscopy was similar with the variable-stiffness paediatric colonoscope and adult colonoscope (95.8% versus 96.6%, p=1.0). Factoring in scope changes, the final frequency was 98.3% versus 99.2% (p=1.0). There was no statistical difference between the two groups in terms of insertion time, doses of sedative medications, scales of procedure difficulty, or patient satisfaction. CONCLUSIONS: Adult colonoscope and variable-stiffness paediatric colonoscope are both effective instruments for routine colonoscopy. In cases when the use of the initial scope is unsuccessful, switching to the alternative scope may permit passage to the caecum. There are occasional patients with fixed, angulated sigmoid colons in whom use of an even thinner diameter paediatric colonoscope can be helpful.     

When and why a colonoscopist should discontinue colonoscopy by himself?

AIM: To investigate when and why a colonoscopist should discontinue incomplete colonoscopy by himself.METHODS: In this cross-sectional study, 517 difficult colonoscope insertions(Grade C, Kudo's difficulty classification) screened from 37800 colonoscopy insertions were collected from April 2004 to June 2014 by three 4th-level(Kudo's classification) colonoscopists. The following common factors for the incomplete insertion were excluded: structural obstruction of the colon or rectum, insufficient colon cleansing, discontinuation due to patient's discomfort or pain, severe colon disease with a perforation risk(e.g., severe ischemic colonopathy). All the excluded patients were re-scheduled if permission was obtained from the patients whose intubation had failed. If the repeat intubations were still a failure because of the difficult operative techniques, those patients were also included in this study. The patient's age, sex, anesthesia and colonoscope type were recorded before colonoscopy. During the colonoscopic examination, the influencing factors of fixation, tortuosity, laxity and redundancy of the colon were assessed, and the insertion time( 10 min or ≤ 10 min) were registered. The insertion time was analyzed by t-test, and other factors were analyzed by univariate and multivariate logistic regression.RESULTS: Three hundred and twenty-two(62.3%) of the 517 insertions were complete in the colonoscope insertion into the ileocecum, but 195(37.7%) failed in the insertion. Fixation, tortuosity, laxity or redundancy occurred during the colonoscopic examination. Multivariate logistic regression analysis revealed that fixation(OR = 0.06, 95%CI: 0.03-0.16, P 0.001) and tortuosity(OR = 0.04, 95%CI: 0.02-0.08, P 0.001) were significantly related to the insertion into the ileocecum in the left hemicolon; multivariate logistic regression analysis also revealed that fixation(OR = 0.16, 95%CI: 0.06-0.39, P 0.001), tortuosity(OR0.23, 95%CI: 0.13-0.43, P 0.001), redundancy(OR = 0.12, 95%CI: 0.05-0.26, P 0.001) and sex(OR = 0.35, 95%CI: 0.20-0.63, P 0.001) were significantly related to the insertion into the ileocecum in the right hemicolon. Prolonged insertion time( 10 min) was an unfavorable factor for the insertion into the ileocecum.CONCLUSION: Colonoscopy should be discontinued if freedom of the colonoscope body's insertion and rotation is completely lost, and the insertion time is prolonged over 30 min.     

Short turn radius colonoscope in an anatomical model: Retroflexed withdrawal and detection of hidden polyps

AIM: To evaluate the new Retro View~(TM) colonoscope and compare its ability to detect simulated polyps "hidden" behind colonic folds with that of a conventional colonoscope, utilizing anatomic colon models.METHODS: Three anatomic colon models were prepared,with twelve simulated polyps "hidden" behind haustral folds and five placed in easily viewed locations in each model. Five blinded endoscopists examined two colon models in random order with the conventional or Retro View~(TM) colonoscope, utilizing standard withdrawal technique. The third colon model was then examined with the Retro View~(TM) colonoscope withdrawn initially in retroflexion and then in standard withdrawal. Polyp detection rates during standard and retroflexed withdrawal of the conventional and Retro View~(TM) colonoscopes were determined. Polyp detection rates for combined standard and retroflexed withdrawal(combination withdrawal) with the Retro View~(TM) colonoscope were also determined.RESULTS: For hidden polyps, retroflexed withdrawal using the Retro View~(TM) colonoscope detected more polyps than the conventional colonoscope in standard withdrawal(85% vs 12%, P = 0.0001). For hidden polyps, combination withdrawal with the Retro View~(TM) colonoscope detected more polyps than the conventional colonoscope in standard withdrawal(93% vs 12%, P ≤ 0.0001). The Retro View~(TM) colonoscope in "combination withdrawal" was superior to other methods in detecting all(hidden + easily visible) polyps, with successful detection of 80 of 85 polyps(94%) compared to 28(32%) polyps detected by the conventional colonoscope in standard withdrawal(P 0.0001) and 67(79%) polyps detected by the Retro View~(TM) colonoscope in retroflexed withdrawal alone(P 0.01). Continuous withdrawal of the colonoscope through the colon model while retroflexed was achieved by all endoscopists. In a post-test survey, four out of five colonoscopists reported that manipulation of the colonoscope was easy or very easy.CONCLUSION: In simulated testing, the Retro View~(TM) colonoscope increased detection of hidden polyps. Combining standard withdrawal with retroflexed withdrawal may become the new paradigm for "complete screening colonoscopy".     

Use of a variable-stiffness colonoscope decreases the dose of patient-controlled sedation during colonoscopy: a randomized comparison of 3 colonoscopes

BACKGROUND: The variable-stiffness colonoscope incorporates different degrees of stiffness of the insertion tube, which can be adjusted during the examination. Whether its use can lead to reduced procedure-related pain and sedative use is unknown. OBJECTIVE: Our purpose was to compare the use of 3 types of colonoscope with different shaft stiffnesses in relation to procedure-related pain and sedative consumption. DESIGN: Prospective randomized trial. SETTING: Endoscopy unit of a university-affiliated hospital. PATIENTS: Consecutive patients undergoing ambulatory colonoscopy. INTERVENTIONS: Random assignment was made of patients into 3 groups to receive colonoscopic examinations by one of the 3 types of colonoscope: conventional standard adult size, 1.3-m; 1.6-m; and the new variable-stiffness adult size, full-length (1.6-m) colonoscope. A mixture of propofol and afentanil, delivered by a patient-controlled syringe pump, was used for sedation in all groups. MAIN OUTCOME MEASURES: Outcome measures included dose of patient-controlled sedation consumed, pain score, cecal intubation rate, cecal intubation time, requirement of abdominal pressure and change of patients' positions during colonoscopy, and endoscopists and patients' satisfaction scores according to a visual analog scale. RESULTS: A total of 335 patients were randomized. Patients in group 3 used significantly less propofol (in milligrams per kilograms, mean [SD]) compared with the other 2 groups (group 1: 1.00 [0.75], group 2: 0.93 [0.62], and group 3: 0.75 [0.65]; P = .02; 1-way analysis of variance). The mean (SD) pain score was also lower in group 3. LIMITATIONS: The endoscopists were not blinded. CONCLUSION: The use of the new variable-stiffness adult-size colonoscope significantly reduced procedure-related pain and doses of sedative medications during colonoscopy.     

Carbon dioxide insufflation during withdrawal of the colonoscope improved postprocedure discomfort: a prospective, randomized, controlled trial

In colonoscopy, the question of when and how to use carbon dioxide (CO(2)) insufflation remains uncertain. Inspection for the pathological changes during colonoscopy takes place during the withdrawal of the scope. This study aimed to determine whether CO(2) insufflation only at the withdrawal of the colonoscope has an effect comparable to that of CO(2) usage throughout the course of the procedure. Symptomatic patients were randomized in three groups: (1) patients given air insufflation (A; n = 33); (2) patients given CO(2) insufflation only at the time of scope withdrawal (CW; n = 33); and (3) patients given the CO(2) insufflation (C; n = 34) for the whole course of the colonoscopy. Patients were requested to answer questionnaires about their pain score during, at the end, and 1 h after the colonoscopy by using a pain numerical scale ranging from 0 to 10. The disparities of the pain score were noted at the end of the procedure and 1 h after the procedure (p = 0.026 and p < 0.001, respectively). We further analyzed the scores between two of the three groups. Both CW (vs. A; procedure end: p = 0.012, 1 h after: p = 0.001) and C (vs. A; procedure end: p = 0.072, 1 h after: p < 0.001) showed less postprocedure pain when compared with the group A. The pain score between CW and C were similar at each time segment (procedure end: p = 0.555, 1 h after: p = 0.491). CO(2) insufflation merely at the withdrawal of the colonoscope improved postprocedural abdominal discomfort and the effect was not inferior to that of full course CO(2) insufflation.     

Sedation-free colonoscopy using an upper endoscope is tolerable and effective in patients with low body mass index: a prospective randomized study

OBJECTIVE: Small-caliber upper endoscopes can be used safely and effectively for sedation-free colonoscopy. The objective of the study is to assess the efficacy of a small-caliber upper endoscope (9.2 mm) comparing with a standard colonoscope (12.2 mm). METHODS: In a prospective trial, patients undergoing sedation-free colonoscopy were randomly assigned to the upper endoscope (E) or the standard colonoscope (C). Outcome measures included patient self-assessed pain score (4-point scale), endoscopist-assessed pain score (4-point scale), cecal intubation rate, difficult cecal intubation rate (>900 s), number of polyps detected, and complication rates. RESULTS: A total of 244 patients were entered. Clinical characteristics were not different between the two groups. Cecal intubation was achieved in 91.0% of the patients in each group. The mean patient self-assessed pain score (SD) was significantly lower in the E group compared with the C group: 1.44 (0.81) versus 2.08 (1.10), p < 0.001. The mean endoscopist assessment of patient pain score (SD) was significantly lower in the E group compared with the C group as well: 1.27 (0.67) versus 1.58 (0.90), p= 0.003. In patients with low body mass index (BMI < 22 kg/m(2)), the cecal intubation rate was significantly higher in the E group (97.7%vs 79.4%, p= 0.026) and the difficult cecal intubation rate was significantly lower in the E group (9.3%vs 32.4%, p= 0.011). There were no significant differences in the number of polyps detected and complication rates between the two groups. CONCLUSION: A small-caliber upper endoscope is tolerable and effective for sedation-free colonoscopy, especially in patients with low BMI.     

Utility of single and double balloon endoscopy in patients with difficult colonoscopy: A randomized controlled trial

AIM: To compare the utility of single-balloon colonoscopy (SBC) or double-balloon colonoscopy (DBC) for difficult colonoscopies. METHODS: Between August 2008 and June 2010, patients in whom total colonoscopy failed within 30 min of insertion were assigned randomly to undergo either SBC or DBC. No sedatives were used. After the endoscopy, all patients were asked to evaluate pain during the procedure on a 10-point analog scale (1 = no pain; 10 = worst imaginable pain) with a questionnaire. The study outcomes were the cecal intubation rate and time, endoscopic findings, complications, and pain score. RESULTS: The SBC and DBC groups included 11 and 10 patients, respectively. All but one SBC patient achieved total colonoscopy successfully. The cecal intubation times were 18 min (range: 10-85 min) and 12.8 min (range: 9.5-42 min) in the SBC and DBC groups, respectively (P= 0.17). No difference was observed in the prevalence of colon polyps between the SBC and DBC groups (45% vs 30%, P = 0.66). SBC showed advanced colon cancer in the ascending colon, which was inaccessible using conventional colonoscopy. The respective pain scores were 5 (1-10) [median (range)] and 5 (1-6) in the SBC and DBC groups (P = 0.64). No complications were noted in any patient. CONCLUSION: The utility of singleand double-balloon endoscopy for colonoscopy seems comparable in patients with incomplete colonoscopy using a conventional colonoscope.