Usefulness of a small-caliber, variable-stiffness colonoscope as a backup in patients with difficult or incomplete colonoscopy

OBJECTIVES: Although variable-stiffness colonoscopes have been developed, difficult or incomplete colonoscopies occasionally occur. The aim of this study was to evaluate the usefulness of a small-caliber, variable-stiffness colonoscope (scVSC) as a backup in patients with difficult or incomplete colonoscopies. METHODS: First, we retrospectively reviewed the cecal intubation rate of colonoscopies in which an adult standard colonoscope (AC) was immediately switched to an scVSC in all patients in whom a colonoscopy with an AC was incomplete. Second, 374 consecutive patients were randomized to undergo colonoscopy with a pediatric variable-stiffness colonoscope (PVSC, n = 123), AC (n = 125), or scVSC (n = 126). The scVSC was used by the same endoscopist to reattempt colonoscopy immediately after colonoscopy with a PVSC or an AC had been assessed as difficult or incomplete. The cecal intubation rate and time and the ancillary maneuvers used were evaluated. RESULTS: Fifty-two (2.5%) of the 2,056 attempted colonoscopies with an AC did not reach the cecum. Fifty-one of the 52 patients (98.1%) had complete colonoscopies after the switch from the AC to the scVSC. The initial intubation rate and time were not statistically different among the groups: PVSC, 95% and 6.8 min; AC, 91% and 7.5 min; and scVSC, 98% and 8.2 min. Cecal intubation was achieved in all five patients (100%) and in 10 out of 11 (91%) patients, respectively, after the PVSC or AC was switched to the scVSC. CONCLUSIONS: The completion rate markedly improved after switching from an AC or PVSC to an scVSC in difficult or incomplete colonoscopies, although the scVSC does not appear to offer any distinct advantage over the AC or PVSC for routine colonoscopies.     

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.     

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.     

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.     

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.     

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.     

Usefulness of a pediatric colonoscope for routine colonoscopy in women who have undergone hysterectomy

BACKGROUND: Colonoscopy can be difficult in some women who have undergone hysterectomy, which can be associated with a fixed, angulated sigmoid colon caused by postoperative pelvic adhesions. Our goal was to determine whether colonoscopy is easier and more comfortable for women after hysterectomy when performed with a pediatric colonoscope, which is thinner in diameter and more flexible than a standard "adult" colonoscope. METHODS: One hundred women with a history of hysterectomy undergoing outpatient colonoscopy were randomized in unblinded fashion to colonoscopy with a standard colonoscope (CF-100L or CF-Q140L, Olympus) or with a pediatric colonoscope (PCF-100, Olympus). All procedures were performed by a faculty endoscopist and timed. After examination, the endoscopist graded procedure difficulty, and patients were given a questionnaire that assessed their experience. RESULTS: The cecum was intubated more frequently in the pediatric colonoscope group than in the standard colonoscope group (96.1% vs. 71.4%, p < 0.001). Success increased in the standard colonoscope group to 89.8% when the pediatric colonoscope was used to complete the examination. There were no differences in the two groups in terms of mean total procedure times (21.4 minutes vs. 22.6 minutes), mean doses of meperidine administered (57 mg both groups), mean doses of midazolam administered (1.5 mg vs. 1.7 mg), scales of procedure difficulty as graded by the endoscopists, and comfort scales as graded by patients. For the cases in which the cecum was intubated, the mean time to reach the cecum (11.7 minutes for the pediatric colonoscope group vs. 12.7 minutes for the adult) was similar. CONCLUSIONS: The pediatric colonoscope is a reasonable choice for colonoscopy in women who have had a hysterectomy. Alternatively, if the endoscopist elects to start the procedure with a standard colonoscope, it is helpful to have a pediatric colonoscope available for use should a fixed, angulated sigmoid colon be encountered that cannot be easily or safely traversed with the standard colonoscope.     

Intermediate-length colonoscope needs more training duration than long-length colonoscope

Abstract

Objective. Few data are available on the influence of a colonoscope length for trainees, which could affect both the duration of training and colonoscopy quality. We conducted this study to validate which scope needs more duration for training to reach technical competence and to shows better quality indicators during diagnostic colonoscopy. Materials and methods. We conducted a prospective randomly assigned study from April 2010 to February 2011 at Asan Medical Center. Among the 1329 patients enrolled, 1200 colonoscopies were analyzed. We compared cecal intubation rate, adenoma detection rate, cecal intubation time (<20 min), and withdrawal time between the trainees using the intermediate-length colonoscope and those using long-length colonoscope. Results. Trainees who used the long-length colonoscope showed a higher overall cecal intubation rate (88.2% vs. 81.0%, p = 0.001) and adenoma detection rate (49.7% vs. 34.2%, p < 0.001) than those using the intermediate-length colonoscope. The successful cecal intubation rate improved significantly and reached the requisite standard of competence (>90%) after 90 procedures in the long-length colonoscope group. However, the trainees using the intermediate-length colonoscope reached the requisite standard of competence after 150 procedures. Logistic regression analysis revealed that prolonged cecal intubation was associated with the use of the intermediate-length colonoscope, poor colon preparation, a small number of esophagastroduodenoscopy or sigmoidoscopy procedures conducted, and pain during procedures. Conclusions. During the same training period, use of the long-length colonoscope in trainee was better in terms of reaching competency and quality indicators, and was less painful for the patients during colonoscopic procedures.     

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.)     

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.     

A prospective trial of variable stiffness colonoscopes with different tip diameters in unsedated patients

OBJECTIVES: Few data exist comparing the clinical versatility of variable stiffness (VS) colonoscopes with different tip diameters and stiffness ranges. We compared the intubation time and success rate, maneuvering ease, and patient comfort of three colonoscopes: pediatric VS (PVSC), nonmagnifying adult VS (AVSC), and magnifying VS (MVSC).
METHODS: Two hundred sixteen consecutive patients scheduled for routine colonoscopy were randomized to undergo colonoscopy with one of the three different colonoscopes (PVSC N = 72, AVSC N = 72, MVSC N = 72). Outcome measurements included time required for cecal intubation, success rate for cecal intubation, maneuvering ease, and patient comfort.
RESULTS: The overall success rate for cecal intubation was 95.83%. Intubation time was significantly different among the groups (PVSC 12.88 ± 7.11 min, AVSC 9.25 ± 5.16 min, MVSC 9.62 ± 5.55 min; P < 0.01). Intubation time with PVSC required about 3 min more when compared with AVSC or MVSC. Multivariate analyses revealed that colonoscopy with AVSC required 3 min less when compared with PVSC ( P = 0.03). Age greater than 55 yr, waist circumference, prior hysterectomy, and pain experienced by patients were also factors affecting intubation time.
CONCLUSIONS: In this study, a PVSC might not decrease patient discomfort or intubation time. The ideal colonoscope is the AVSC that has a modest diameter and stiffness range and thus is capable of achieving both a short intubation time and an acceptable comfort level. We also should bear in mind that MVSC has an additional function of magnifying observation.     

Method of colonoscopy in 42 consecutive patients presenting after prior incomplete colonoscopy

OBJECTIVES: Cecal intubation is one of the goals of colonoscopy. We sought to describe the methodology used by a single experienced examiner to perform colonoscopy in a consecutive group of patients with challenging colons. METHODS: Records of 42 consecutive patients with one or more prior unsuccessful attempts at colonoscopy by a gastroenterologist or surgeon and referred for a repeat attempt at colonoscopy were reviewed. RESULTS: Colonoscopy was complete to the cecum in 40 of the 42 patients (95%). An array of methods was employed, including propofol sedation (n = 2), pediatric colonoscope (n = 8), an external straightener (n = 9), external straightener with pediatric colonoscope (n = 2), upper endoscope (n = 8), guidewire exchange (n = 3), and enteroscope with a colon straightener (n = 1) or an enteroscope straightener (n = 1). CONCLUSIONS: A variety of methods and instruments were employed to achieve a high cecal intubation rate during colonoscopy in a group of patients with prior incomplete colonoscopies. Others may find one or more of these methods useful in patients with challenging colons.     

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.     

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.     

Using the Gastroscope for Incomplete Colonoscopy

PURPOSE Reports of virtual colonoscopy demonstrate sensitivity similar to that of conventional colonoscopy for polyps 5 mm or larger, suggesting the validity of its use for colorectal cancer screening. Critical to the success of either procedure is the ability to evaluate the entire colon. Cecal intubation rates during diagnostic or screening colonoscopies vary from 53 to 99 percent. We describe the added value of using a gastroscope to perform a colonoscopic examination that would otherwise result in an incomplete colonoscopy.METHODS From January 1, 2002 to December 31, 2002 a total of 1,979 colonoscopies were performed. A gastroscope was used in 1.3 percent (n = 26) of these colonoscopies in an effort to complete the index examination initially started with a standard or pediatric colonoscope. The success rate was defined as intubating proximal to the initial area of impasse and entering the cecum.RESULTS Cecal intubation was achieved in 62 percent of patients.CONCLUSIONS In patients with incomplete conventional colonoscopy, the gastroscope can usually advance through the initial area of impasse with a cecal intubation rate of 62 percent.Presented at The American Society of Colon and Rectal Surgeons Annual Meeting, Dallas, Texas, May 8 to 13, 2004.     

(Technically) Difficult colonoscope insertion – Tips and tricks

Cecal intubation is a critical aspect of effective, complete colonoscopy. Difficult colonoscopy is most often considered as one in which it is challenging or impossible to reach the cecum. It may be a common occurrence due to patient and/or endoscopist factors. Incomplete colonoscopies should be avoided, since patients in this context present an important prevalence of lesions that escape examination. The approach to successful cecal intubation should depend on characterization of the problem as redundant colon or difficult sigmoid colon. Most patients with a prior incomplete colonoscopy can be colonoscoped successfully, if careful attention is paid to technique, using a variety of scopes, colonoscopy methods and additional equipment. Sufficient time should be allotted to make the attempt.     

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 retrospective analysis of cecal barotrauma caused by colonoscope air flow and pressure

BACKGROUND: This study addressed the question of whether barotrauma during colonoscopy is sufficient to rupture the colon. METHODS: A total of 3000 colonoscopies were retrospectively analyzed, and the colonoscopes used for these procedures were evaluated in an in vitro analysis. Air pressure at the tip of the colonoscopes and air flow through the instruments were measured. The equation F=F MAX-P TIP/R was used to graph flow values (F) from the maximum measured flow (F MAX), the calculated resistance to air flow offered by the colonoscope (R), and the air pressure observed at the colonoscope tip (P TIP ). RESULTS: Four perforations occurred during 1500 consecutive colonoscopies performed with equipment from one manufacturer (Pentax Precision Instrument Corp., Orangeburg, NY) whereas, no perforation occurred during 1500 consecutive colonoscopies performed with equipment from another manufacturer (Olympus America Corp., Melville, NY) ( p < or =0.06). The Pentax colonoscopes used in patients with barotrauma-induced cecal perforations insufflated air at a rate greater than 1.46 L/m at 80 mmHg intraluminal pressure. Olympus colonoscopes did not. In vitro maximum air-flow rates of 2 L/m at a tip pressure of 0 mm Hg separated the Pentax from the Olympus instruments ( p <0.022). Conclusions Colonoscopes with maximum flow rates of less than 2 L/m at 0 mmHg tip pressure have insufficient flow capacity to generate flows above 1.46 L/m at 80 mmHg intraluminal pressure and thus may protect patients from cecal barotrauma.     

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.     

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.