Colonoscopy: go small for success?

Colonoscopy using standard adult colonoscopes can be difficult in patients with fixed, angulated sigmoid colons. An earlier study from the same center suggested that in women who have had hysterectomy, successful colonoscopy occurred with greater frequency when initiated with a pediatric colonoscope versus an adult colonoscope. This follow-up study was a nonblinded clinical trial comparing the use of a pediatric colonoscope with an adult colonoscope for routine colonoscopy in women with previous hysterectomy. A total of 100 female patients presenting for an outpatient colonoscopy were randomized to use the pediatric (Olympus PCF-100) or adult (Olympus CF-100L or CF-Q140L) colonoscope.
The primary outcome was the comparative rate of cecal intubation. Secondary outcomes included total procedure time, cecal insertion time, sedative administration, procedural difficulty, and patients' experience. Endoscopists encountering difficult insertion had the opportunity to use the alternate scope. The cecum was reached in 49 of 51 (96.1%) women when using the pediatric colonoscope versus 35 of 49 (71.4%) women when using the adult colonoscope. Of the 14 incomplete examinations initiated with an adult colonoscope, the pediatric colonoscope was used 12 times, and the cecum was reached in nine, adjusting the rate of successful colonoscopy to 44 of 49 (89.8%). There was no statistical difference in total procedure time, cecal insertion time, sedative drug dosages, procedural difficulty, or patient comfort using either scope.
When performing routine colonoscopy in women with previous hysterectomy, the authors recommend either starting with a pediatric colonoscope or having one available in the advent of a fixed, angulated sigmoid colon.     

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.     

Use of a pediatric colonoscope improves the success of total colonoscopy in selected adult patients

Background: Colonoscopy using a standard adult colonoscope can be difficult or impossible when there is a fixed, angulated sigmoid colon or stricture. It is sometimes possible to traverse such segments using a smaller-diameter, more flexible pediatric colonoscope. Methods: For this prospective study, one endoscopist started 645 consecutive, elective colonoscopies with a standard adult Olympus CF-100L colonoscope (52% women, 48% men). There were 36 examinations (5.6%) in which the adult colonoscope could not be passed through a fixed, angulated sigmoid colon (n = 34) or a sigmoid colonic stricture (n = 2). In such instances (33 women and 3 men), the endoscopist switched to a pediatric colonoscope. Results: The pediatric colonoscope successfully reached the cecum in 21 of the 36 cases (58.3%). The figure was 38.5% for the older Olympus CF-P20L fiberoptic colonoscope (n = 13) and 69.6% for the newer Olympus PCF-100 videocolonoscope (n = 23). Concomitant conditions in the 34 patients in whom the pediatric colonoscope was used because of a fixed, angulated sigmoid included previous pelvic surgery in 22, pelvic radiation therapy in 2, pelvic endometriosis in 3, and two with previous sigmoid diverticulitis. Conclusions: The pediatric colonoscope, and particularly the newer Olympus PCF-100 colonoscope, is very useful in adult patients in whom it is not possible to traverse a fixed, angulated sigmoid colon or stricture using the standard adult colonoscope. This is predominantly a problem of female patients. Previous pelvic surgery may be an important causative factor in this regard. (Gastrointest Endosc 1996;44:675-8.)     

A prospective trial of variable stiffness pediatric vs. standard instrument colonoscopy

BACKGROUND: The pediatric variable stiffness colonoscope is believed to have theoretical advantages over the standard colonoscope, however a systematic evaluation of this instrument in routine clinical practice involving adult patients is lacking. METHODS: Consecutive patients (blinded) undergoing colonoscopy in an outpatient endoscopy center by one of 4 experienced colonoscopists had the procedure performed with a standard colonoscope (n=384) or pediatric variable stiffness colonoscope (n=413). Failure to negotiate the sigmoid colon within 10 minutes was regarded as a failure and, if suitable, the patient was crossed over to colonoscopy with the alternative instrument. RESULTS: Median (95% CI) time to the cecum was significantly faster in the pediatric variable stiffness colonoscope group (odds ratio 5.0: 95% CI[4.7,5.3] minutes) compared with the standard colonoscope group (odds ratio 5.5: 95% CI[5.2,5.8] minutes, p=0.01). There were 22 failures overall (2.8%), 14 in the standard colonoscope group (3.6%) and 8 in the pediatric variable stiffness colonoscope group (1.9%; p=0.1). With regard to the 14 failures in the standard colonoscope group, colonoscopy was attempted with the pediatric variable stiffness colonoscope in 13 and completed successfully in 12 (92%). The pediatric variable stiffness colonoscope was superior in cases of severe stenosing diverticular disease; two of 27 examinations with the pediatric variable stiffness colonoscope were rated as failed vs. 12 of 18 with the standard colonoscope (p<0.001). CONCLUSIONS: Intubation time was faster with the pediatric variable stiffness colonoscope, but use of this instrument was not associated with a superior cecal intubation rate compared with the standard colonoscope. However, in patients with severe stenosing diverticular disease, the intubation rate with the pediatric variable stiffness colonoscope was superior.     

Ultrathin colonoscope with a diameter of 9.8 mm for total colonoscopy

BACKGROUND: The pediatric colonoscope is superior to the standard colonoscope in some patients with a fixed, angulated colon. A colonoscope thinner than the pediatric one is thought to outperform even the pediatric colonoscope in such cases. This study was conducted to assess the efficacy of an ultrathin colonoscope, 9.8 mm in diameter, comparing it with pediatric and standard colonoscopes. METHODS: Three types of colonoscopes were used: ultrathin, pediatric, and standard. A total of 287 consecutive patients were assigned to three groups: ultrathin (n=94), pediatric (n=98), and standard (n=95). First assessment was the ratio of cecal intubation and the reasons for unsuccessful colonoscopy. The second was the time to cecal intubation. RESULTS: Cecal intubation rates were not different among three groups (96% in each). The main reasons for failed colonoscopy were looping in the ultrathin group, and angulation or stricture in the pediatric and standard groups. Mean time to the cecum was slightly longer in the ultrathin group (6.5 minutes) than the pediatric group (5.6 minutes) and standard group (6.1 minutes), but there were no significant differences among three groups. CONCLUSION: Colonoscopy with the ultrathin colonoscope was as successful as with the pediatric and standard colonoscopes. The advantage of the ultrathin colonoscope might be notable in cases with stricture or severe angulation.     

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.     

Usefulness of pediatric colonoscopes in adult colonoscopy

Use of small diameter, extraflexible pediatric colonoscopes has proved to be valuable in adult endoscopy practice, not only for passing strictures and stomas but also where either fixation due to diverticular disease or postoperative adhesions, or unavoidably painful looping made passage of adult colonoscopes impossible. In 70 of 78 (92%) of the cases where the adult colonoscope could not be passed through the sigmoid colon by an expert endoscopist, the pediatric colonoscope passed through, often very easily. Fifteen of these patients were considered to have been saved surgery by successful passage. The "failure" rate for all colonoscopy examinations was only 2%; this low failure rate was attributable to the use of pediatric instruments whenever passage through the sigmoid colon proved to be impossible with standard colonoscopes. In our opinion every unit performing frequent colonoscopies should have a pediatric colonoscope available for selected adult patients as well as for use in children.     

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.     

Incomplete colonoscopy: Maximizing completion rates of gastroenterologists

BACKGROUND

Cecal intubation is one of the goals of a quality colonoscopy; however, many factors increasing the risk of incomplete colonoscopy have been implicated. The implications of missed pathology and the demand on health care resources for return colonoscopies pose a conundrum to many physicians. The optimal course of action after incomplete colonoscopy is unclear.

OBJECTIVES:

To assess endoscopic completion rates of previously incomplete colonoscopies, the methods used to complete them and the factors that led to the previous incomplete procedure.

METHODS:

All patients who previously underwent incomplete colonoscopy (2005 to 2010) and were referred to St Paul’s Hospital (Vancouver, British Columbia) were evaluated. Colonoscopies were re-attempted by a single endoscopist. Patient charts were reviewed retrospectively.

RESULTS:

A total of 90 patients (29 males) with a mean (± SD) age of 58±13.2 years were included in the analysis. Thirty patients (33%) had their initial colonoscopy performed by a gastroenterologist. Indications for initial colonoscopy included surveillance or screening (23%), abdominal pain (15%), gastrointestinal bleeding (29%), change in bowel habits or constitutional symptoms (18%), anemia (7%) and chronic diarrhea (8%). Reasons for incomplete colonoscopy included poor preparation (11%), pain or inadequate sedation (16%), tortuous colon (30%), diverticular disease (6%), obstructing mass (6%) and stricturing disease (10%). Reasons for incomplete procedures in the remaining 21% of patients were not reported by the referring physician. Eighty-seven (97%) colonoscopies were subsequently completed in a single attempt at the institution. Seventy-six (84%) colonoscopies were performed using routine manoeuvres, patient positioning and a variable-stiffness colonoscope (either standard or pediatric). A standard 160 or 180 series Olympus gastroscope (Olympus, Japan) was used in five patients (6%) to navigate through sigmoid diverticular disease; a pediatric colonoscope was used in six patients (7%) for similar reasons. Repeat colonoscopy on the remaining three patients (3%) failed: all three required surgery for strictures (two had obstructing malignant masses and one had a severe benign obstructing sigmoid diverticular stricture).

CONCLUSION:

Most patients with previous incomplete colonoscopy can undergo a successful repeat colonoscopy at a tertiary care centre with instruments that are readily available to most gastroenterologists. Other modalities for evaluation of the colon should be deferred until a second attempt is made at an expert centre.     

Tapered colonoscope performs better than the pediatric colonoscope in female patients: a direct comparison through tandem colonoscopy

BACKGROUND: The pediatric variable-stiffness colonoscope (PVSC) is used by many endoscopists to negotiate the colon that requires a flexible colonoscope; it has a smaller diameter, but may lead to excessive looping. A prototype colonoscope tapers from an adult width to a pediatric diameter at approximately 25 cm. The tapered colonoscope (TC), while retaining the flexibility of the PVSC, has the column strength of the adult colonoscope to help negotiate the proximal colon. OBJECTIVE: Our hypothesis is that use of the TC in female patients would be associated with less looping than the PVSC during the procedure, fewer required maneuvers, and thus a quicker examination. DESIGN: Direct comparison through tandem colonoscopies. SETTING: University endoscopy suite. PATIENTS: Forty unselected female patients. INTERVENTIONS: Tandem colonoscopies with PVSC and TC. MAIN OUTCOME MEASUREMENTS: Time to the cecum and the ability to retroflex in the cecum. RESULTS: Compared with the PVSC, the TC had faster times to achieve cecal intubation (mean [standard deviation], 8.83+/-4.68 minutes versus 6.88+/-4.08 minutes; P=.013) and a higher rate of retroflexion in the cecum (31/40 patients vs 39/40 patients; P<.01). Use of the TC was associated with a decreased need for abdominal pressure (P<.001). CONCLUSIONS: The TC achieved faster cecal intubation rates and had a higher success of cecal retroflexion than a PVSC. This performance likely was because of diminished looping and thus a decreased need for maneuvers. The TC may be preferable to the PVSC for female patients.     

Use of a push enteroscope improves ability to perform total colonoscopy in previously unsuccessful attempts at colonoscopy in adult patients

Objective: Total colonoscopy with use of a standard adult colonoscope can be difficult in the presence of a redundant or angulated colon. It is often possible to traverse these areas with the use of a thinner, more flexible endoscope. The objective of this study was to evaluate the efficacy of completing total colonoscopy using a push enteroscope when a standard colonoscope was unsuccessful. Methods: A prospective analysis was performed for 721 consecutive colonoscopies attempted by two gastroenterologists. Those patients in whom complete colonoscopy was unsuccessful using the standard colonoscope (Olympus CF-100L) had attempts to complete colonoscopy using the enteroscope (Olympus SIF-100). The extent of each exam was recorded. Additional pathologic findings discovered by the use of the enteroscope and therapeutic interventions performed were additionally noted. Results: Colonoscopy using an enteroscope was performed in 32 patients with successful total colonoscopy in 22 patients (68.7%). Additional pathology was noted in nine patients who had successful complete colonoscopy using the enteroscope; adenomatous polyp (  n = 5  ), adenocarcinoma (  n = 1  ), bleeding source (  n = 2  ), and extent of colitis (  n = 1  ). Total colonoscopy rate using standard adult colonoscope was 93.2% (630 of 676) when cases with poor bowel preparation (  n = 23  ) and obstructing lesions (  n = 14  ) were excluded. When the results of successful colonoscopies with the enteroscope were included, the overall completion rate of total colonoscopy improved to 96.4% (652 of 676). Conclusion: The use of the enteroscope to help evaluate patients who have had incomplete colonoscopies with the standard colonoscope increases the diagnostic yield of colonic examination.     

Prospective evaluation of a small caliber upper endoscope for colonoscopy after unsuccessful standard examination

Colonoscopy is unsuccessful in some patients because of a fixed sigmoid loop or anatomical stenoses. We prospectively evaluated 1600 patients undergoing colonoscopy at Virginia Mason Medical Center from December 1, 1986 to November 31, 1987. Thirty-one procedures (1.9%) failed to reach the splenic flexure because of functional or anatomic stenoses. Attempt at pancolonoscopy with a 9.8-mm diameter, 102-cm length endoscope (Olympus XQ) was successful to the right colon in 73% and cecum in 60% of these patients. Two thirds of the successfully intubated patients had clarification of radiographic abnormalities or delineation of additional colon pathology. There were no complications or instrument damages, but limitations included short scope length and small suction channel. We conclude that small diameter upper endoscopes can be used safely and effectively for colonoscopy in a subset of patients in whom conventional colonoscopy is unsuccessful.     

Use of enteroscope without the overtube in incomplete colonoscopies

Abstract

Objectives: Colonoscopy is the gold standard diagnostic method for colorectal cancer (CRC) screening. Despite the progress in the endoscopy technology field, a small percentage of colonoscopies is still incomplete. The reasons for that are mostly associated with anatomic features, such as fixed, angulated, long and loopy colon, intra-abdominal adherences and female gender. To overcome such difficulties, the usefulness of scopes different from conventional adult colonoscope (CF), such as paediatric colonoscope (PCF), gastroscope (GIF), single and double balloon enteroscope (SBE and DBE, respectively), has been shown in literature. Our retrospective study aims to evaluate the caecal intubation rate using a SBE without the overtube in patients who previously underwent an incomplete procedure with a different scope.

Methods: Patients with a previous incomplete colonoscopy with CF, PCF or GIF were retrospectively enrolled through the analysis of a dedicated database. The enteroscope used was the Olympus Enteropro Single Balloon SiF-Q180 with no overtube. Complete colonoscopy was defined as successful caecal intubation.

Results: SBE was used to scope 47 adult patients, mostly female, and it led to a complete procedure in 91% of them. The most frequent reason for an incomplete procedure even with the use of SBE was a fixed and angulated colon.

Conclusions: Colonoscopy performed with SBE was safe and no adverse events during and/or after the procedure occurred. Our results suggest that SBE with no overtube is a useful and valid alternative to other type of scopes in difficult cases, especially those related to fixed/angulated colon and in female gender.     

Total colonoscopy: is it always possible?

One-thousand three hundred fifty-one consecutive colonoscopies were performed in an office setting without fluoroscopy. Three different models of colonoscopies were utilized; all were manufactured by the Olympus Corporation of America, and included a videoendoscope, a CF-20L immersible OES-type instrument, and an older fiberoptic colonoscope, CFLB-3W. In all colonoscopies, the cecum was reached in 95.9%, even when an obstructing lesion or stenosis was present. Total intubation was performed in 97% of cases with the videoendoscope, 95.5% with the CF-20L, and 95.7% with the CFLB-3W. In a subgroup of 865 colonoscopies, total colonoscopy was performed in 98% of cases when obstructing lesions (carcinoma or stricture) were excluded from analysis. In this subgroup, total colonoscopy could not be performed in 16 patients because of colonic fixation, tortuosity, or for unknown anatomical reasons. Forty-five percent of this subgroup was female, but of the 16 patients in whom total colonoscopy was not possible, 15 were women, 5 of whom had a previous hysterectomy. We conclude that in the absence of any obstructing lesion, an expert can perform complete colonoscopy in 98% of examinations, and in 95% of all patients presenting for colonoscopy. Total colonoscopy may be more difficult in women than men, but a previous hysterectomy does not seem to adversely affect the ability to perform colonoscopy. The type of instrument used for colonoscopy does not impact on the ability to visualize the entire colon.     

The variable stiffness colonoscope: assessment of efficacy by magnetic endoscope imaging

BACKGROUND: Variable-stiffness colonoscopes combine the flexibility of pediatric instruments for negotiation of the sigmoid colon with the ability to stiffen the insertion tube to prevent or control looping after straightening. Previous studies have found wide variation in the efficacy of the stiffening mechanism. Thus, two studies were conducted to assess the potential benefit of the stiffening device and its optimal use. METHODS: In study 1, the effect of routinely stiffening the straightened variable-stiffness colonoscopes in the mid-descending colon was determined in 82 patients. Two insertions were performed (mid-descending colon to cecum) in each patient with and without application of the stiffening device (randomized). The time to negotiate the proximal colon (mid-descending to cecum), time to pass the variable-stiffness colonoscopes across the splenic flexure into the transverse colon, time to pass the right colon, and ancillary maneuvers used were recorded for each insertion. In study 2, consecutive patients, excluding any with previous colonic resection, were examined by using standard adult variable-stiffness colonoscopes. Real-time views of the procedure with magnetic endoscope imaging were recorded for all examinations, but procedures were randomized to be done either with (n = 88), or without (n = 87) the endoscopist viewing the magnetic endoscope imaging display. Whenever stiffening was applied, the anatomic location of the colonoscope tip and stiffness efficacy were recorded. RESULTS: In study 1, time taken to negotiate the proximal colon (p = 0.0041) and time to negotiate the splenic flexure (p = 0.006) were significantly shorter and ancillary maneuvers performed were fewer (p = 0.0014) with the stiffening device activated. In study 2, stiffening was used with similar frequency in patients examined with and without the magnetic endoscope imaging view, most commonly for passing the splenic flexure (71%), but also in the transverse colon (12%), right colon (9%), and sigmoid/descending colon (8%). Stiffening was significantly more effective when used in combination with magnetic endoscope imaging (69% with imager vs. 45% without imager; p = 0.0102). CONCLUSIONS: Overall, the variable-stiffness device used was effective in controlling looping 57% of the time. Activating maximum stiffness appears to be effective once the sigmoid colon has been negotiated and the colonoscope straightened with the tip in the proximal colon, reducing the number of ancillary maneuvers and shortening the insertion time through the proximal colon. Routine magnetic endoscope imaging further enhances the efficacy of the variable-stiffness colonoscopes by helping to identify the optimal time for stiffening.     

Factors that predict incomplete colonoscopy

PURPOSE AND METHODS: Certain factors in a patient's history, such as prior abdominal surgery or complicated diverticular disease, have been reported to hinder cecal intubation during colonoscopy. Over a 16-month period, 1,047 consecutive colonoscopies were prospectively evaluated to determine whether these factors were indeed clinically relevant. RESULTS: Of the 90 patients (9 percent) who had incomplete intubation of the colon, there were significantly more women (66 percent) than men (34 percent) (P <0.001). Women with a history of abdominal hysterectomy had a significantly lower cecal intubation rate (P < 0.01). A history of diverticulitis did not alter the cecal intubation rate. In patients with incomplete colonic intubation, the most proximal extent of intubation was the sigmoid colon in women (31 percent) and the right colon in men (68 percent). Sixty-seven percent of patients with incomplete intubation of the colon had a prior colonoscopy completed to the cecum (67 percent women, 67 percent men), whereas 50 percent had a follow-up colonoscopy completed to the cecum (56 percent women, 40 percent men). CONCLUSIONS: Women, especially those with a history of abdominal hysterectomy, had a significantly lower cecal intubation rate usually because of an impassable sigmoid colon. Prior inability to complete colonoscopy to the cecum does not necessarily forecast future failure.Poster presentation at the meeting of The American Society of Colon and Rectal Surgeons, Montreal, Quebec, Canada, May 7 to 12, 1995.     

Inadequacy of colonoscopy revealed by three-dimensional electromagnetic imaging

INTRODUCTION: It is generally accepted that clinicians performing colonoscopy should reach the cecum in at least 90 percent of examinations. However, little attention has been paid to whether the endoscopist correctly estimates the amount of colon actually seen. METHODS: During colonoscopy, endoscopists were asked to state how far they had reached. This was compared with the amount of colon actually seen, as assessed by a novel electromagnetic imaging device that recorded a three-dimensional position of the scope within a magnetic field pervading the patient's abdomen. If electromagnetic imaging showed that the cecum had not been reached, the endoscopist was asked to use the electromagnetic imaging system to determine whether it helped advance the colonoscope further. RESULTS: In 119 patients undergoing colonoscopy, clinical assessment of position reached was correct in only 92 (77.3 percent). When the endoscopists stated that cecal landmarks had been seen (n=85), the scope was distal to the cecum in seven cases (8.2 percent). When cecal landmarks had not been seen (n=34), the endoscopist's assessment of the position of the scope was accurate in only 14 (41.2 percent). The use of electromagnetic imaging in this latter group assisted passage to the cecum in 26 cases (76.5 percent). CONCLUSION: Despite assumed visualization of the cecum, inadequate colonoscopy highlights the potential for missing significant pathology in the right colon.The electromagnetic imaging system used in this study was donated by the University Department of Electronics, University of Sheffield, United Kingdom.Presented in part or in full at the British Society of Gastroenterology Meeting, Harrogate, United Kingdom, March 10, 1998; the Royal Society of Medicine Section of Coloproctology Meeting, Grenoble, France, April 15, 1998; and the Tripartite Meeting, Washington, DC, May 4, 1999.     

Accessing proximal aspects of folds and flexures during colonoscopy: impact of a pediatric colonoscope with a short bending section

OBJECTIVE: Accessing the proximal sides of colorectal folds, flexures, and valves can be difficult endoscopically and can contribute to missed lesions and failed therapeutic procedures. The aim of this study was to determine whether a prototype colonoscope with a short bending section could facilitate accessing difficult to reach areas proximal to folds, flexures, and valves. METHODS: In a nonrandomized study, the prototype colonoscope, a standard pediatric colonoscope, and a standard adult colonoscope were used to attempt retroflexion in the cecum and, if unsuccessful, in the right colon. RESULTS: The prototype colonoscope allowed cecal retroflexion, including clear visualization of the ileocecal valve and the cecal mucosa medial to the valve, in 95% of attempts. A standard pediatric colonoscope was successful in 50% and a standard adult colonoscope in 24.5%. The prototype was more successful than both the standard pediatric (p < 0.001) and the standard adult instrument (p < 0.001). The standard pediatric colonoscope was successful more often than the standard adult colonoscope (p = 0.02). CONCLUSIONS: Using the ability to retroflex in the cecum as a surrogate marker, a prototype pediatric colonoscope with a short bending section seems to facilitate retroflexion and visualization of the proximal aspects of difficult to see regions in the proximal colon.     

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.     

A randomized controlled trial of total colonic decompression after colonoscopy to improve patient comfort

OBJECTIVES: Bloating occurring after colonoscopy may cause significant discomfort in some patients. We sought to determine whether total colonic decompression decreased bloating and improved comfort after colonoscopy. METHODS: Consecutive outpatients undergoing elective colonoscopy were randomized to total colonic decompression or to the control group after completion of the routine colonoscopy. The colonoscope was advanced again to the cecum and the air aspirated during withdrawal in patients randomized to decompression and the procedure was terminated without decompression in control patients. Pain and bloating was assessed in the recovery room and in 24-48 h using a five-point scale. RESULTS: Sixty-five patients were randomized to decompression and 61 were randomized to the control group. The baseline demographic and procedural characteristics were similar between the two groups, but decompression took significantly longer (median, 17 min vs 14 min, p = 0.0002). Seventy-five percent of the decompression group and 80% of the control group denied any pain during colonoscopy. Significantly fewer patients from the decompression group complained of bloating after the procedure (25% vs 59%, p < 0.001) when questioned in the recovery room. However, comparable patients complained of postprocedure bloating when questioned in 24-48 h after the procedure (45% of decompression group vs 47% of control group, p = 0.86). The nurse and the endoscopist were poor at predicting the patient's bloating and significantly overestimated the level of pain. CONCLUSIONS: Total colonic decompression does not significantly reduce bloating after colonoscopy when assessed 24-48 h after the procedure.