Incomplete colonoscopy: Maximizing completion rates of gastroenterologists

Department of Medicine, Division of Gastroenterology, St Paul’s Hospital, University of British Columbia, Vancouver, British Columbia Correspondence: Dr Robert Enns, Suite 770, 1190 Hornby Street, Vancouver, British Columbia V6Z 2K5. Telephone 604-688-6332 ext 222, fax 604-689-2004, e-mail rob.enns@ubc.ca Received for publication October 1, 2011. Accepted December 20, 2011 Since its introduction in the late 1960s, the technology of colonoscopy has progressed rapidly, as has the technological success of experienced endoscopists (1,2). Cecal intubation is one of the main goals of colonoscopy; however, complete colonoscopy rates vary considerably. Incomplete colonoscopies pose a clinical concern because management strategies to assess patients with incomplete colonoscopies vary. For radiological assessment following incomplete procedures, double-contrast barium enema (DCBE) was commonly used in the past; however, it has now been replaced by computed tomography colonography (CTC) in many centres (3). CTC has come to the orIgInal artIcle


METhodS
The colonoscopy reports of all patients undergoing colonoscopy by a single endoscopist (RE) from 2005 to 2010 at St Paul's Hospital in Vancouver, British Columbia, were reviewed.St Paul's Hospital is affiliated with the University of British Columbia (Vancouver, British Columbia) and is a tertiary referral centre for advanced endoscopic procedures and successfully performs approximately 10,000 colonoscopies per year with a 97% completion rate.The primary endoscopist in the present study (RE) has a crude completion rate of 99.6%, performing approximately 1000 colonoscopies/year.Patients with incomplete colonoscopy were identified by systematically reviewing computerized medical records of patients who underwent colonoscopy.No colonoscopy was performed at our institution before re-attempt.The inclusion criteria were an incomplete colonoscopy and referral to one gastrointestinal (GI) specialist (RE).All colonoscopies were re-attempted by a single gastroenterologist (RE).Repeat colonoscopies performed by other gastroenterologists at our institution were not analyzed or included in the present study.Procedures were performed between 07:30 to 11:30, and bowel preparation was achieved using Pico-Salax (Ferring Pharmaceuticals Inc, Canada).A standard 180 series Olympus (Olympus, USA) adult colonoscope was used for all cases initially.Patients were sedated with intravenous doses of 2 mg midazolam and 50 μg fentanyl, which were titrated to patient comfort.The patients' heart rate and oxygen saturation were monitored throughout the procedure.Routine manoeuvres (ie, air insufflation, water cleanse) and change of patient position were used to advance the colonoscope as necessary.All patients were scheduled into a standard 30 min endoscopy slot.Complete colonoscopy was defined as visualisation and intubation of the cecum, confirmed by identification of the ileocecal valve and triradiate fold.Details of the first endoscopist, place of original endoscopy, patient sex, reason for incomplete colonoscopy and steps taken to complete colonoscopy (if applicable) were noted.Results are presented in descriptive statistics.Means and SDs are used to report continuous variables following a normal distribution, and median (range) are used to report non-normal continuous variables.The study was approved in writing by the local ethics committee and conducted according to the Declaration of Helsinki.

RESulTS
Ninety patients (mean [± SD] age 58±13.2years, 32% male) were included in the analysis.Thirty patients (33%) had their initial colonoscopy performed by a gastroenterologist in a nonacademic institution.The remainder of the incomplete colonoscopies were performed by general surgeons and internal medicine specialists in both academic and nonacademic hospitals.Indications for initial colonoscopic evaluation included surveillance or screening (23%) (either colorectal cancer or inflammatory bowel disease), abdominal pain not yet diagnosed (15%), GI bleeding (29%), change in bowel habits or constitutional symptoms (18%), anemia not yet diagnosed (7%) and chronic diarrhea (8%) (Figure 1).Reasons for incomplete colonoscopy included poor preparation (11%), patient discomfort (16%), tortuous or redundant colon (30%), diverticular disease (6%), obstructing mass (6%) and stricturing disease (10%) (Figure 2).No reason for the incomplete procedures was reported for the remaining 21% of patients.Eighty-seven colonoscopies were subsequently completed at St Paul's Hospital, with a crude completion rate of 96.8%.Seventy-six (84%) were performed using routine manoeuvres, patient positioning and a standard 180 series Olympus colonoscope.A standard 160-or 180-series Olympus gastroscope was used in five patients (6%) to navigate through sigmoid diverticular disease; a pediatric colonoscope was used in six patients (7%) for similar reasons (Table 1).An overtube or an enteroscope was not used.No procedures were performed under fluoroscopy.No patients required sedation doses exceeding what gastroenterologists would deem acceptable and, similarly, propofol was not used.All patients had their re-attempted colonoscopy performed within a mean of 30±5 min.No complications occurred during repeat colonoscopy.Colonoscopy on the remaining three patients (3%) failed because two had a malignant obstructing mass and one had a severe diverticular stricturing disease; none of these strictures would permit passage of a standard gastroscope.All three required surgical intervention, with surveillance of the remaining colon performed after surgery.

dISCuSSIon
The importance of an incomplete colonoscopy poses a diagnostic dilemma for many endoscopists.The reported rate of incomplete colonoscopies ranges from 4% to 25% according to published reports (12)(13)(14)(15), and increases with age up to a rate of 22% to 33% (16).Reasons for incomplete colonoscopy have been reported in previous studies and include redundant or tortuous colon (particularly sigmoid colon), marked diverticular disease, obstructing masses and strictures, angulation or fixation of colonic loops, adhesions due to previous surgery, spasm, poor colonic preparation, female sex or older age, and a low body mass index (17)(18)(19).Furthermore, Sanaka et al (20) found operator fatigue to play an important role because colonoscopies performed later in the day had higher rates of incompletion.In the largest study to date comparing colonoscopies performed at a tertiary care centre with those performed at community hospitals or in private offices, Shah et al ( 21) reported a higher failure rate in colonoscopies performed elsewhere versus those performed at a tertiary care centre.Subsequently, numerous techniques have been used to complete previous incomplete colonoscopies including lumbar epidural analgesia, use of a gastroscope, external straightener (ie, overtube) and a pediatric colonoscope, with all having varying success (4)(5)(6)(7)22).
Nevertheless, other methods, such as DCBE, have been proposed as an alternative choice to evaluate the colon after incomplete colonoscopy.Due to its noninvasive nature and the ease of access associated with DCBE, it was regarded as a viable option.However, two largescale prospective studies have shown DCBE to have low accuracy in detecting colonic neoplasms, with sensitivity for adenomas >9 mm in size in the range of 45% to 50% (23)(24)(25).Given the false-positive rate of 5% to 10% reported in the literature for polyps >1 cm in size, the need for repeat colonoscopy when lesions are found on barium images in the nonvisualized colon unnecessarily increase the cost of the diagnostic work-up in a small percentage of patients (26).
CTC is accurate in detecting colorectal neoplasms, as reported in meta-analyses (27,28), revealing sensitivities in the range of 85% to 90%, and specificities of approximately 95% for polyps >9 mm in size.In addition, several studies have shown CTC to be a valuable tool in evaluating the proximal colon after incomplete colonoscopy (29)(30)(31)(32)(33)(34).Furthermore, the American Gastroenterologists Association has recognized the role of CTC in adults who fail colonoscopy (3).However, most of these studies evaluated CTC in the context of colorectal cancer detection (ie, screening), which as shown in our study, does not comprise most of our incomplete colonoscopies.The majority of our patients had significant symptoms and, therefore, a higher prevalence of disease and higher likelihood of requiring endoscopic intervention.This high prevalence of pathology mandates endoscopic therapeutic intervention not available through CTC.The role of CTC is limited, particularly in the setting of lower GI bleeding.In some cases, colonic collapse or repletion by fluid or feces may preclude evaluation of the rectum, sigmoid or descending colon.Subsequently, a significant number of false positives may result, which inevitably leads to repeat colonoscopy.Additionally, guidelines for average-risk patients undergoing CTC are presently at five years, whereas those with optical colonoscopy are at 10 years (35).Provided that colonoscopy can be completed safely at an expert centre, it appears that therapy and diagnosis can be achieved while providing the longest interval between repeat procedures, resulting in ideal resource use.
Initially designed for deep and even complete intubation of the small bowel, double-balloon enteroscopy (DBE) has played a role in incomplete colonoscopy.Technically more flexible and narrow, DBE enables the user to navigate through acute angulations and redundant colon effectively and easily while preventing the colon from looping on itself, and still offering the advantage of therapeutic intervention.Several studies have demonstrated the efficacy of DBE in completing previously incomplete colonoscopies, with success rates in the range of 88% to 97% (4-7).However, procedure time (average 50.6 min), endoscopist expertise and staffing (one assistant to help with the procedure and another for patient monitoring) required to perform DBE are major drawbacks.Until mechanical and technical refinements are made to this relatively new modality, effort and cost utility would not be preferred over repeating colonoscopy in the long term.
Our study, although similar in many aspects to previous studies, highlights other key points not mentioned that may be useful for endoscopists.Whereas previous analyses of incomplete studies primarily investigated screening or surveillance for colorectal cancer, our study recognized other reasons for which colonoscopy was used because there are other pathologies aside from colorectal cancer affecting patient morbidity and mortality (Figure 1).Only 21 (23%) of our patients underwent their initial colonoscopy for surveillance or screening purposes.Furthermore, our study highlights another aspect of care, namely, repeat colonoscopies should be performed at a tertiary care centre by an experienced gastroenterologist who may have the available techniques and perhaps more experienced nursing staff to complete challenging colonoscopies.In the present study, more than 95% of colonoscopies were completed because only those limited by strictures (both benign and malignant) were incomplete.No advanced techniques of enteroscopy or fluoroscopy were used.Endoscopy units must be aware that simple methods for completion of procedures in many settings, including titrated sedation and appropriate allotment of time, are adequate as opposed to considering new and relatively expensive alternatives that may not offer the same advantages.
Our study has limitations that we acknowledge.First, the experience of the endoscopists performing the initial colonoscopy was not known, which may or may not have contributed to higher incompletion rates.Similarly, only one endoscopist at our institution (RE) performs repeat colonoscopies and the high completion rate may reflect the skill of the endoscopist; however, we believe that the techniques used to complete our procedures are within the capabilities of most gastroenterologists practicing in a tertiary care centre.Second, we acknowledge that specific sedation requirements were not recorded in the initial colonoscopy; therefore, enhanced patient comfort at our institution may have allowed for better completion rates.Finally, our institution uses Pico-Salax as its bowel preparation and, although it was difficult to determine what preparation solution was used for the initial incomplete colonoscopy, we believe that rather than preparation being the problem, patient compliance/factors may have played a role.

dISCloSuRES:
The authors have no financial disclosures or conflicts of interest to declare.

ConCluSIon
Our study highlights issues regarding previously incomplete colonoscopies.With appropriate expertise and readily available endoscopic instrumentation, 95% of previously incomplete colonoscopies can be completed by a gastroenterologist at a tertiary care centre.Other modalities of investigating the colon (CTC, DCBE, balloon enteroscopy) are rarely required in this setting.We recommend that regional sites develop specific expertise in endoscopic capabilities so the number of incomplete procedures can be minimized.Additionally, all sites should ensure that targets for procedure completion rates, as suggested by numerous regional authorities, are being met, and that quality initiatives encourage ongoing assessment and improvement in these parameters.