Failed Colonoscopy Research Articles

Evaluating the Safety and Quality of Diagnostic Colonoscopies Performed by General Surgeons: A Retrospective Study.

Introduction Colonoscopy, which is a challenging procedure and requires adequate time to master the skill, is the procedure of choice to visualize colonic mucosa to rule out many colonic pathologies. There is a dearth of published information from real clinical experiences regarding successful procedures and limitations. The end point of colonoscopy is the visualization of the cecal pole by intubating the cecum. Many Europeans and English health organizations recommend that the procedure should have a completion rate of around or above 90%. Gut preparation is an important determinant for a successful procedure and obviates the need for further invasive and/or expensive procedures such as imaging. The majority of colonoscopies are being performed by gastroenterologists (GI) throughout the world, and the role of a surgeon as an endoscopist is in debate. Before this study, neither a retrospective nor a prospective evaluation of the general surgeon's (GS) endoscopy's quality and safety had been evaluatedin our institution. Material and method This retrospective observational study was carried out from 1January2022 to 31August2022 in the Department of Surgery at Mayo Hospital, Lahore, to evaluate colonoscopy completion rates, reason for failure, and complications in terms of bleeding and perforation. All patients undergoing lower gastrointestinal endoscopy (LGiE), both elective and emergency, were included. Patients under 15 years of age and patients known to be hepatitis B-positive or hepatitis C-positive were excluded from the study. All relevant data were entered into a data sheet. Qualitative variables such as gender, cecal intubation, adjusted cecal intubation, gut preparation, reasons for failed colonoscopy, analgesia use, and complications (bleeding and perforation) were calculated as frequency and percentage. Quantitative data such as age and pain score were reported as mean and standard deviation (SD). Details obtained were tabulated and analyzed via the Statistical Package for Social Sciences (SPSS) version 29.0 (IBM SPSS Statistics, Armonk, NY). Results A total of 57 patientdata were collected; 35.1% (n=20) were female, and 64.9% (n=37) were males. The cecal intubation rate (CIR) was 49.1% (n=28), and the adjusted rate was 71.9%, excluding incompleteness due to mass obstructing lumen, 8.8% (n=5); planned left colonoscopy, 7% (n=4); sigmoidoscopy, 3.5% (n=2); distal stoma scope, 1.8% (n=1); and colonic stricture, 1.8% (n=1). The prevalent reason for failed colonoscopy was inadequate gut preparation (15.8% {n=9}). Other reasons include patientdiscomfort, 3.5% (n=2); looping of scope, 7% (n=4); and acute colonic angulation, 1.8% (n=1). No complications were recorded. Conclusion This study shows that colonoscopy can be done by general surgeons safely and effectively with adequate training. High rates of cecal intubation emerge during colonoscopies performed under deep sedation and by skilled colonoscopists. Adequate bowel preparatory regimen is compulsory for quality procedure.

Three-dimensional reconstruction of computed tomography colonography discloses anatomic features associated with colonoscopy failure.

Three-dimensional virtual reality (3D VR) permits precise reconstruction of computed tomography (CT) images, and these allow precise measurements of colonic anatomical parameters. Colonoscopy proves challenging in a subset of patients, and thus CT colonoscopy (CTC) is often required to visualize the entire colon. The aim of the study was to determine whether 3D reconstructions of the colon could help identify and quantify the key anatomical features leading to colonoscopy failure. Retrospective observational study. Using 3D VR technology, we reconstructed and compared the length of various colonic segments and number of bends and colonic width in 10 cases of CTC in technically failed prior colonoscopies to 10 cases of CTC performed for non-technically failure indications. We found significant elongation of the sigmoid colon (71 ± 23 cm versus 35 ± 9; p = 0.01) and of pancolonic length (216 ± 38 cm versus 158 ± 20 cm; p = 0.001) in cases of technically failed colonoscopy. There was also a significant increase in the number of colonic angles (17.7 ± 3.2 versus 12.7 ± 2.4; p = 0.008) in failed colonoscopy cases. Increased sigmoid and pancolonic length and more colonic bends are novel factors associated with technical failure of colonoscopy.

SPLIT-DOSE BOWEL PREPARATION IS SUPERIOR TO STRAIGHT-DOSE IN HOSPITALIZED PATIENTS UNDERGOING INPATIENT COLONOSCOPY.

There is a two-fold higher rate of failed colonoscopy secondary to inadequate bowel preparation among hospitalized versus ambulatory patients. Split-dose bowel preparation is widely used in the outpatient setting but has not been generally adapted for use among the inpatient population. The aim of this study is to evaluate the effectiveness of split versus single dose polyethylene glycol bowel (PEG) preparation for inpatient colonoscopies and determine additional procedural and patient characteristics that drive inpatient colonoscopy quality. A retrospective cohort study was performed on 189 patients who underwent inpatient colonoscopy and received 4 liters PEG as either split- or straight-dose during a 6-month period in 2017 at an academic medical center. Bowel preparation quality was assessed using Boston Bowel Preparation Score (BBPS), Aronchick Score, and reported adequacy of preparation. Bowel preparation was reported as adequate in 89% of the split-dose group versus 66% in the straight-dose group (P=0.0003). Inadequate bowel preparations were documented in 34.2% of the single-dose group and 10.7% of the split-dose group (P<0.001). Only 40% of patients received split-dose PEG. Mean BBPS was significantly lower in the straight-dose group (Total: 6.32 vs 7.73, P<0.001). Split-dose bowel preparation is superior to straight-dose preparation across reportable quality metrics for non-screening colonoscopies and was readily performed in the inpatient setting. Interventions should be targeted at shifting the culture of gastroenterologist prescribing practices towards use of split-dose bowel preparation for inpatient colonoscopy.

Patient Education After Inadequate Bowel Preparation: Improving Care and Outcomes.

A colonoscopy is recommended for prevention and early detection of colorectal cancers. A high-quality bowel preparation is associated with adequate polyp detection and one of the colonoscopy preparation quality measures. However, many patients arrive for colonoscopy appointments with inadequate bowel preparation, and approximately 20% of patients with colonoscopy failure were not adherent to instructions. The purpose of this study was to determine whether using a questionnaire would improve the outcomes of patient education and proper bowel preparation. Charts were reviewed to develop a patient questionnaire. A mix of open-and closed-ended, patient-centered questions were developed to further patient education in a time-efficient manner and achieve consistent responses for determining barriers and issues, improve documentation, and then assist the patient in achieving a good-to-excellent quality bowel preparation. Proper cleansing instructions as well as identifying and overcoming barriers to achieving adequate bowel preparation for colonoscopy can result in improved patient satisfaction, care quality, and cost savings.

A134 A MULTI-CENTRE RANDOMIZED CONTROLLED TRIAL TO COMPARE TWO BOWEL CLEANSING REGIMENS AFTER A COLONOSCOPY WITH INADEQUATE BOWEL PREPARATION

Abstract Aims Failed bowel preparation is common during colonoscopy, yet the optimal purgative regimen to use for the next attempt is unknown. The objective of this study was to compare the efficacy, tolerability, and safety of two regimens at supratherapeutic doses for use after failed bowel preparation. Methods A multi-centre phase III endoscopist blinded randomized controlled trial (NCT02976805) was conducted in patients who failed bowel preparation, using the US Multi-Society Task Force (USMSTF) definition of inability to exclude polyps &amp;gt;5 mm in size and requiring a shortened interval to next colonoscopy. Regimen A consisted of 15 mg of bisacodyl and 2 + 2 L of split dose polyethylene glycol electrolyte solution (PEG) and Regimen B consisted of 15 mg of bisacodyl and 4 + 2 L of split dose PEG. The primary outcome was adequate bowel preparation, defined as a Boston Bowel Preparation Scale (BBPS) total score ≥ 6 with all segment scores ≥ 2. Secondary outcomes were adequate bowel preparation using the USMSTF definition, median BBPS, adenoma detection (ADR), advanced adenoma detection (aADR), sessile serrated polyp detection (SSPDR), and cecal intubation (CIR). Adverse events were assessed at the time of the colonoscopy and 14 days later. Results Between February 2017 and December 2019, 250 subjects were screened at four academic centres in Canada, of which 195 were randomized: 96 to Regimen A and 99 to Regimen B. The mean (SD) age was 60.6 (11.4) years, 87 (45.1%) were female, and the median (IQR) total BBPS score at previous failed colonoscopy was 3 (1,4). Regimen B was not superior to Regimen A in achieving adequate bowel preparation using the BBPS definition (87.6% vs. 91.1%, p=0.45) or the USMSTF definition (85.4% vs 91.1%, p=0.24), nor was it superior with respect to the median BBPS score (7 vs 7, p=0.50), mean ADR (31.5% vs 37.8%, p=0.37), aADR (11.2% vs 18.9%, p=0.15), SSPDR (5.6% vs 8.9%, p=0.40) or CIR (92.1% vs 96.7%, p=0.19). Regimen A had a higher adherence rate (88.2% vs. 74.7%, p=0.02) and greater willingness to undergo the bowel preparation again (91.2% vs. 66.2%, p&amp;lt;0.001). The only serious adverse event occurred in a patient randomized to Regimen B who was admitted to hospital for vomiting after colonoscopy. Conclusions Split dose 4L PEG with 15mg of bisacodyl is highly efficacious, well tolerated, and can be used for patients who previously failed first line bowel preparations. The additional 2L of PEG in Regimen B did not improve bowel preparation and was not as well tolerated. Funding Agencies AMOSO Opportunities Grant, Pharmascence Inc.

Preoperative CT Colonography in Partially Obstructed Colon Cancer, and its Benefit in Surgical Management

Background and aims Stenotic colorectal carcinoma impending obstruction (SCRCIO) is a frequently encountered situation complicating 10% to 19% of colorectal cancers. This group of patients cannot undergo complete colonoscopic assessment. The aim of this study is to examine the accuracy of computed tomographic colonography (CTC) as preoperative assessment of the colon of patients with SCRCIO and to measure the effect on the surgical decision. Materials and methods This was a prospective study, from September 2009 through December 2012, on a cohort of symptomatic adult patients with SCRCIO. Patients underwent CTC evaluation after failed conventional colonoscopy (CC), followed by a follow-up endoscopic examination 3–6 months after surgical treatment. Results Twenty-nine patients with an average age of 55 were included in this study; the majority of stenotic masses were located in the sigmoid colon. Preoperative CTC matched the colonoscopy location of the stenotic masses (17 patients). CTC sensitivity per stenotic lesion detection was 100% and 92.5% for the location. Sensitivity was 100% for synchronous lesions, and CTC changed surgical plan in 17% of the patients. Conclusion CTC presented high sensitivity, specificity and accuracy for the identification of colonic lesions of any size. Preoperative CTC may possibly become the diagnostic procedure of choice for SCRCIO patients. It enables surgeons to evaluate the entire colon, minimizing the possibility of surgical re-intervention if there is a finding of synchronous neoplastic lesions at postoperative follow-up endoscopy.

2888 Hospitalization for Colonoscopy Preparation and Its Effects on Prep Quality

INTRODUCTION: Colonoscopy is the most commonly used method for colon cancer screening. The quality of prep greatly affects the examination. Risk factors for inadequate prep include prior inadequate prep, male gender, prior surgery, diabetes, low health literacy and cognitive delay. Studies have shown improvement in colonoscopy prep using split-dosing however despite this, inadequate prep continues to be a problem. One solution at our institution is to hospitalize selected patients with prior failed outpatient colonoscopy prep in an attempt to improve the prep quality. METHODS: We retrospectively identified all patients who were hospitalized for colonoscopy prep from 2016 to 2018. Patients who did not have documentation of prep quality were excluded. Data including age, gender, indication for procedure and presence of risk factors was gathered. The prior prep quality and prep quality after admission was documented. RESULTS: 122 patients were included in the study. “Screening” was the most common indication for the procedure. Most of the patients had at least one risk factor for inadequate prep. 90 patients had improvement in their prep quality. CONCLUSION: Bowel prep continues to be inadequate in up to 25% of examinations. Several patient related risk factors for inadequate prep have been identified in previous studies. Patients who have risk factors for slow bowel transit such as immobility, CVA and chronic use of narcotics can also be factors in colon prep. We believe the improvement in bowel prep in our study is related to adherence to dietary restrictions, accurate laxative consumption, and improved assessment of stool clearance. Our study also showed a significant number of improved bowel prep quality in patients who had risk factors for poor prep. The cost of hospitalization was not evaluated in our study. We believe that an adequate bowel would result in a longer time-interval for subsequent colonoscopies and reduced overall cost. Our study is limited given its retrospective design and small number of patients. In addition, given that our software does not allow use of the Boston Bowel Prep Scale, the results may be difficult to generalize to other populations. Repeat studies would be needed to assess cost effectiveness. Quality of bowel prep continues to be a barrier to high quality colonoscopy. This study shows that hospitalized bowel prep may help improve prep quality in a select group of patients in the underserved population and with known risk factors.

Improving bowel preparation for colonoscopy in a cost-effective manner

Poor bowel preparation is the leading cause of failed colonoscopy examinations. Numerous bowel cleansing agents are in use for this purpose; however there is a noticeable limitation to their effectiveness due to variations in their tolerability and side effect profile. An inadequately prepared bowel can lead to missed diagnosis or need for repeat procedures and investigations with a significant financial impact. We reviewed the outcome of colonoscopies performed over a period of 3 months in 625 patients aiming to improve the quality of bowel preparation, and hence quality of the procedure, alongside provision of a cost-effective service. We focused on improving the quality of bowel preparation as an indirect measure of optimal screening procedure. The secondary objective was to amend the type of preparation used and postage methods for outpatients in a cost-effective manner without compromising the quality of …

Retrograde Device Assisted Enteroscopy as a Salvage Procedure for Failed Colonoscopy: The Experience of a large Australian Centre

Aim: Failed caecal intubation occurs in 4-25% of colonoscopies. The primary objective was to assess the technical success of retrograde Device Assisted Enteroscopy (rDAE) after failed colonoscopy. Secondary aims were to describe the diagnoses and interventions, and to identify factors affecting technical success.Methods: Retrospective review of consecutive patients undergoing retrograde DAE at our institution between November 2004 and May 2016. Data were collected on: demographics, technical success, bowel preparation, diagnoses, interventions and adverse events.Results: In total, 277 patients underwent retrograde DAE. Of these, 86 procedures were performed on 82 patients for incomplete colonoscopy, primarily in redundant colons. Cecal intubation was achieved in 80 procedures (93%). Incomplete procedures were caused by unsatisfactory preparation in 5 cases (6%) and by colonic herniation in 1 case (1%). Of the 80 completed procedures, 2 were non-diagnostic due to poor bowel preparation and 20 showed no abnormalities. In the remaining 58 procedures, 66 diagnoses were made: adenomatous polyps (n=25), inflammatory bowel disease (n=14), angioectasias (n=7), colonic diverticulosis (n=6), strictures (n=5), laterally spreading tumours (n=3), adenocarcinomas (n=3), and ileal ulcers (n=2). Interventions performed were: snare polypectomy (n=29), biopsy (n=17), argon plasma coagulation (n=8), endoscopic mucosal resections (n=3), dilatation (n=3) and endoscopic clipping (n=4). No reported adverse events.Conclusion: Salvage retrograde DAE has a high technical success in redundant colons and important diagnostic findings. DAE should be recommended in preference to repeat standard colonoscopy or CT colonography. There should be a strong focus on optimising bowel preparation, as it was the major factor influencing technical success and diagnostic yield.

AB94. 116. Obesity is associated with increased risk of colonoscopy failure

AB94. 116. Obesity is associated with increased risk of colonoscopy failure

Sa1718 Retrograde Device Assisted Enteroscopy as a Salvage Procedure for Failed Colonoscopy: The Experience of an Australian Centre

Failure to intubate the caecum occurs in up to 10% of colonoscopies for various reasons. Significant looping or redundant colon is the most common cause1. This commonly precipitates a referral for CT colonography, which has poor sensitivity for flat lesions and lesions under 1cm. Small studies report that device-assisted enteroscopy (DAE) can achieve high caecal intubation rates (2-5). The primary aim of this study is to assess the technical success rate of retrograde DAE (rDAE) in patients with failed colonoscopy at a tertiary referral academic centre. Secondary aims were to describe the diagnoses and interventions, and to identify predictors of technical success.

Abstract IA05: The serrated pathway of colorectal tumorigenesis

Abstract IA05: The serrated pathway of colorectal tumorigenesis

Optimal timing for faecal tagging in same day CT colonography for patients with failed colonoscopy

AimSame day CT colonography (CTC) for incomplete colonoscopy should be considered to avoid the need for further bowel preparation. Oral administration of contrast is essential for optimal colonic analysis of the CTC. Our aim was to determine the optimal time for giving contrast to people who underwent same day CTC after failed colonoscopy. MethodsData was extracted from the Trust database to identify the number of CTC referrals following failed or incomplete colonoscopy within the last 5 years, and the reason for their referral. Patients were then excluded if they had not received faecal tagging, which included all patients prior to 2013. Two experienced radiologists independently reviewed the CTCs to determine the level of faecal tagging, and this was correlated with the estimated length of time between the administration of the contrast agent and the CTC examination. Results110 patients were identified within the 5 year period who had undergone same day CTC following failed colonoscopy. Reasons for the referral included incomplete colonoscopy (most common indication), contraindication to colonoscopy, poor colonoscopic view, refusal for colonoscopy and data unavailable. 60 patients had received faecal tagging, and two experienced radiologists independently reviewed these CTCs to determine the level of faecal tagging from the caecum to the rectum (complete bowel coverage). ConclusionOur study suggests that contrast should be given approximately 256.4 ± 24.4 (4.27 h) minutes before same day CTC, but this time could be reduced where the left side of the colon had been successfully evaluated by colonoscopy. Further studies with multicentre collaborations are required.

Double-balloon colonoscopy for failed conventional colonoscopy: the Edinburgh experience and systematic review of existing data

Double-balloon colonoscopy for failed conventional colonoscopy: the Edinburgh experience and systematic review of existing data

Patient experience of CT colonography and colonoscopy after fecal occult blood test in a national screening programme

ObjectiveTo investigate patient experience of CT colonography (CTC) and colonoscopy in a national screening programme.MethodsRetrospective analysis of patient experience postal questionnaires. We included screenees from a fecal occult blood test (FOBt) based screening programme, where CTC was performed when colonoscopy was incomplete or deemed unsuitable. We analyzed questionnaire responses concerning communication of test risks, test-related discomfort and post-test pain, as well as complications. CTC and colonoscopy responses were compared using multilevel logistic regression.ResultsOf 67,114 subjects identified, 52,805 (79 %) responded. Understanding of test risks was lower for CTC (1712/1970 = 86.9 %) than colonoscopy (48783/50975 = 95.7 %, p < 0.0001). Overall, a slightly greater proportion of screenees found CTC unexpectedly uncomfortable (506/1970 = 25.7 %) than colonoscopy (10,705/50,975 = 21.0 %, p < 0.0001). CTC was tolerated well as a completion procedure for failed colonoscopy (unexpected discomfort; CTC = 26.3 %: colonoscopy = 57.0 %, p < 0.001). Post-procedural pain was equally common (CTC: 288/1970,14.6 %, colonoscopy: 7544/50,975,14.8 %; p = 0.55). Adverse event rates were similar in both groups (CTC: 20/2947 = 1.2 %; colonoscopy: 683/64,312 = 1.1 %), but generally less serious with CTC.ConclusionsEven though CTC was reserved for individuals either unsuitable for or unable to complete colonoscopy, we found only small differences in test-related discomfort. CTC was well tolerated as a completion procedure and was extremely safe. CTC can be delivered across a national screening programme with high patient satisfaction.Key Points• High patient satisfaction at CTC is deliverable across a national screening programme.• Patients who cannot tolerate screening colonoscopy are likely to find CTC acceptable.• CTC is extremely safe; complications are rare and almost never serious.• Patients may require more detailed information regarding the expected discomfort of CTC.

Case Report: Rectal perforation during CT colonography.

Introduction Computer tomography colonoscopy (CTC) is an increasingly prevalent procedure for the investigation of colorectal symptoms, or as a component of colorectal cancer screening. It is considered a low risk procedure, however colonic perforation is a recognized significant complication. Case Report We report the case of an 81-year-old female patient who underwent CTC after failed optical colonoscopy as part of routine colorectal cancer screening. Perforation of the rectum with surrounding pararectal air was confirmed on CTC. The patient had minimal symptoms and was treated successful non-operatively with bowel rest and antibiotics. Conclusion Perforation sustained during CTC is an uncommon complication. The incidence of perforation during CTC is still lower than that during optical colonoscopy. In the absence of significant abdominal signs and symptoms, this rare complication may be successfully managed non-operatively.

Short Occult Retractile Fibrous Scar Causing Exclusive Retrograde Stenosis of the Sigmoid Colon: An Incidental Diagnosis Nineteen Years After a Single Episode of Colonic Diverticulitis.

We report a rare case of purely retrograde stenosing stricture of the sigmoid descending colonic junction fortuitously diagnosed during the waning of a failed virtual colonoscopy in a 69-year-old patient. The rather asymptomatic patient was addressed to investigate a positive fecal occult blood test. He had suffered a single acute colonic diverticulitis episode 19 years before. A contrast-enhanced abdominal CT and complementary focused abdominal ultrasound fully diagnosed a short curvilinear contrast-enhancing “scar-like” tissue infiltrating the posterior colonic wall and developing retractile adherences with the retroperitoneum of the left iliac fossa. The imaging features are presented with pathologic correlation.

Endoscopic mucosal resection for large serrated lesions in comparison with adenomas: a prospective multicentre study of 2000 lesions

ObjectiveEndoscopic mucosal resection (EMR) is effective for large laterally spreading flat and sessile lesions (LSLs). Sessile serrated adenomas/polyps (SSA/Ps) are linked to the relative failure of colonoscopy to prevent proximal...

Sigmoid Perforation during CT Colonography in a Patient with an Inguinal Hernia and Concomitant Finding of a Right-Sided Colon Cancer

The use of computed tomography colonography or virtual colonography (VC) is gaining acceptance as a screening modality for colon cancer. A comprehensive understanding of VC complications is limited. We report a case of colon perforation in a patient where a colon cancer was diagnosed using VC colonography with manual insufflation. A 79-year-old patient underwent a VC after a failed screening optical colonoscopy (OC). The initial radiological findings included a large amount of mesoperitoneum and retroperitoneal air near the proximal sigmoid and a left inguinal hernia containing the distal sigmoid colon suggesting a colonic perforation caused by colonic obstruction. Subsequent radiological interpretation revealed a 1.5 cm lesion in the posterior cecum. The patient underwent repair of the hernia, sigmoid resection for sigmoid perforation, followed by intra-operative colonoscopy (which confirmed the radiographic findings of a cecal lesion) and right colectomy. Pathologic examination confirmed the T3, N0, MX adenocarcinoma.

P0112 Prediction of complex colonic anatomy before colonoscopy: Use of quantitative CTC data for risk stratification of patients for colon-cancer screening

Background Certain characteristics in patients have been associated with decreased endoscopic performance and outcomes. However, little objective quantitative data have been reported on differences in colonic morphology, which could explain why certain patient populations are at higher risk than others for incomplete or difficult colonoscopy. Poor performance and bad experiences in patients may negatively affect their choice for future screening for colon cancer. Knowledge before colonoscopy of patients with complex morphology could help endoscopists appropriately prepare for these particular patients. Methods Prototype quantification software was used to assess CT colonography datasets. To limit selection bias, all patients had a history of failed colonoscopy. Colonic morphology metrics were investigated, including: length, volume, tortuosity (number of acute angles), compactness (volume of box containing centreline divided by centreline length), and height of the sigmoid apex (HSA). Patient factors assessed included: sex ( n = 40), age ( n = 32), height ( n = 32), BMI ( n = 32), and hysterectomy ( n = 73). Patient groups were compared with the t -test. Distance navigated at colonoscopy was compared and relative risk was assessed. Findings Despite similar lengths, women’s colons were more tortuous and compact, less voluminous, and had lower HSA ( p 65 years), shorter ( p ⩽ 0.05) colons and demonstrated decreased distance travelled at endoscopy, although the differences were not statistically significant. Women with hysterectomy had more tortuous and less voluminous sigmoid segments with lower HSA ( p ⩽ 0.02). At endoscopy, the hysterectomy group had 46% chance of failure to pass the sigmoid segment, versus 22% in the non-hysterectomy group (relative risk 2.068, p = 0.043). Interpretation Differences in colonic morphology exist between patient populations. Factors including female sex, older age, shorter stature, thinner body habitus, and hysterectomy status show quantitative evidence of more complex colonic morphology which can make endoscopy more challenging in these patients. Consideration of these factors could help endoscopists prepare for challenging cases and provide a better screening experience.