Pediatric Variable Stiffness Colonoscope Research Articles

Does retroflexion improve adenoma miss rates on the right side of the colon when using a pediatric variable-stiffness colonoscope during routine colonoscopy?

Optical colonoscopy is widely accepted as the gold standard for detecting colorectal pathology, especially adenomas and cancer. However, even in the most experienced hands, miss rates of adenomas and small cancers of up to 30 % have been reported in the literature [1] [2]. The visibility of the colorectal surface by colonoscopy is only 86.6 % compared with colonography simulation [3]. There are of course several reasons for this, one of which is the difficulty of locating adenomas that are hidden behind proximal sides of folds and the inner aspect of flexures [4] [5] [6], especially in the hepatic flexure, where the colonoscope can slip during removal [7]. Once the cecum is reached, retroflexion is often possible, and this is helpful in examining behind haustra as far as the hepatic flexure. However, retroflexion in the cecum of adult patients has proven to be significantly more successful when pediatric colonoscopes are used compared with when standard instruments are used [8] [9]. Furthermore, retroflexion in the colon facilitates resection of polyps during colonoscopy [10] [11]. So far, the impact of proximal colon retroflexion on adenoma miss rates has been negative when using normal endoscopes [12]. However, the prospective pilot study described below suggests significant advancement in colonoscopy when using pediatric variable-stiffness colonoscopes.

Use of an electromagnetic colonoscope to assess maneuvers associated with cecal intubation

BackgroundSafe and effective colonoscopy is aided by the use of endoscopic techniques and maneuvers (ETM) during the examination including patient repositioning, stiffening of the endoscope and abdominal pressure.AimTo better understand the use and value of ETM during colonoscopy by using a device that allows real-time imaging of the colonoscope insertion shaft.MethodsThe use of ETM during colonoscopy and their success was recorded. Experienced colonoscopists and endoscopy assistants used a commercially available electromagnetic (EM) transmitter and a special adult variable stiffness instrument with 12 embedded sensors to examine 46 patients. In 5 of these a special EM probe passed through the instrument channel of a standard pediatric variable stiffness colonoscope was used instead of the EM colonoscope.ResultsThirty-nine men and 7 women with a mean age of 64 years (range 33–90) were studied. The cecum was intubated in 93.5% (43/46). The mean time to reach the cecum was 10.6 minutes (range 3–25). ETM were used a total of 174 times in 41 of the patients to assist with cecal intubation. When ETM were required to reach the cecum, and the cecum was intubated, an average of 3.82 ETM/patient was used. While ETM were used most often when the tip of the colonoscope was in the left side of the colon (rectum 5.0%, sigmoid colon 20.7%, descending colon 5.0%, and splenic flexure 11.6%), when the instrument was in the transverse colon (14.8%), hepatic flexure (20.7%) and ascending colon (19.8%) the use of ETM was also required. When the colonoscope tip was in the transverse colon, hepatic flexure and ascending colon, ETM success rates were less (61.1%, 52.0%, and 41.7% respectively) compared to the left colon success rates (rectum 83.3%, sigmoid colon 84.0%, descending colon 100%, and splenic flexure 85.7%).ConclusionThe EM colonoscope allows imaging of the insertion shaft without fluoroscopy and is a useful device for evaluating the efficacy of ETM. ETM are important tools of the colonoscopist and are used most often in the left colon where they are most effective.

Carbon Dioxide Insufflation for Potentially Difficult Colonoscopies Performed Without Sedation: Valuable Training for Inexperienced Colonoscopists

Background and Aims: Colonoscopy is a preferred method for screening, diagnosing and treating colorectal cancer, but prolonged cecal intubation can cause increased patient abdominal pain and discomfort especially in difficult cases. A prospective randomized controlled study was conducted to clarify effectiveness of carbon dioxide (CO2) insufflation in potentially difficult cases particularly in relation to the experience levels of participating colonoscopists. Methods: A total of 120 potentially difficult cases involved female patients with a low body mass index and patients with earlier abdominal and/or pelvic open surgery or previously diagnosed left-side colon diverticulosis. Exclusion criteria were severe heart or lung disease, a prior colorectal resection, inflammatory bowel disease, therapeutic procedures as well as incomplete colonoscopies. All examinations were performed without sedation using a pediatric variable-stiffness colonoscope with patients divided into CO2 and standard air insufflation groups. Midazolam (2-3mg/iv) was administered based on an individual colonoscopist's judgment or a patient's request after complaining of abdominal pain or distension. Insufflation procedures were also evaluated based on the background of colonoscopists who were divided into experienced colonoscopist (EC) and less experienced colonoscopist (LEC) groups. Study measurements included a visual analogue scale (VAS) to assess patient pain during and after colonoscopy examinations in addition to cecal intubation and withdrawal times. Results: There were no significant differences in baseline patient characteristics including eligibility criteria for potentially difficult cases between the two groups. Neither were there any procedure-related complications in either group. Midazolam was administered to two patients (4%) in each group. Examination times did not differ, but VAS scores were significantly better in the CO2 group than in the air group (p<0.001; two-way ANOVA) from immediately following the procedures until two hours afterwards. There were no significant differences between either insufflation method in the EC group (p=0.29), but VAS scores for CO2 were significantly better than those for air in the LEC group (p=0.023) from right after the procedures until four hours later. Conclusions: The clinical effectiveness of CO2 insufflation was clearly demonstrated in potentially difficult colonoscopy examination cases performed without sedation. In particular, this procedure's rapid CO2 absorption and improved efficacy reduced patient pain after colonoscopies performed by LECs so we recommend incorporating its use in colonoscopy training programs.

CO2 insufflation for potentially diffcult colonoscopies:Effcacy when used by less experienced colonoscopists

To clarify the effectiveness of CO(2) insufflation in potentially difficult colonoscopy cases, particularly in relation to the experience level of colonoscopists. One hundred twenty potentially difficult cases were included in this study, which involved females with a low body mass index and patients with earlier abdominal and/or pelvic open surgery or previously diagnosed left-side colon diverticulosis. Patients receiving colonoscopy examinations without sedation using a pediatric variable-stiffness colonoscope were divided into two groups based on either CO(2) or standard air insufflation. Both insufflation procedures were also evaluated according to the experience level of the respective colonoscopists who were divided into an experienced colonoscopist (EC) group and a less experienced colonoscopist (LEC) group. Study measurements included a 100-mm visual analogue scale (VAS) for patient pain during and after colonoscopy examinations, in addition to insertion to the cecum and withdrawal times. Examination times did not differ, however, VAS scores in the CO(2) group were significantly better than in the air group (P < 0.001, two-way ANOVA) from immediately after the procedure and up to 2 h later. There were no significant differences between either insufflation method in the EC group (P = 0.29), however, VAS scores for CO(2) insufflation were significantly better than air insufflation in the LEC group (P = 0.023) immediately after colonoscopies and up to 4 h afterwards. CO(2) insufflation reduced patient pain after colonoscopy in potentially difficult cases when performed by LECs.

Comparing Different Methods of Activating the Variable Stiffness Function of a Pediatric Variable Stiffness Colonoscope

Previous studies on variable stiffness colonoscopes showed mixed results. Different methods of activating the variable stiffness function were used and might explain part of the controversy. To determine the most efficient way of activating the variable stiffness function, this study compared 3 methods (no activation, regular activation, activation on an as-needed basis) using 1 single type of pediatric variable stiffness colonoscope. Asymptomatic patients admitted for physical check-up at the Buddhist Dalin Tzu Chi General Hospital were included. A single endoscopist performed all of the colonoscopic examinations of patients under sedation using a variable stiffness pediatric colonoscope. Consecutive patients were randomized to undergo colonoscopy using 3 different methods of activating the variable stiffness function: no activation ("no" group), regular activation at descending colon ("regular" group), and activation on an as-needed basis ("as-needed" group). Completion rate, cecal intubation time, and use of adjunct measures were evaluated and compared among the 3 groups. Subgroup analysis by gender was also performed. Between January and July 2006, a total of 250 patients were enrolled. The completion rates of the examinations were 97.6%, 91.7% and 96.4% in the no, regular and as-needed groups, respectively (p = 0.17). The cecal intubation times were 5.6 +/- 2.6 minutes, 5.6 +/- 2.7 minutes and 6.2 +/- 2.3 minutes, respectively (p = 0.22). Multivariate logistic regression analysis showed that activation of the variable stiffness function regularly (odds ratio [OR], 0.53; 95% confidence interval [CI], 0.28, 0.98; p = 0.04) or on an as-needed basis (OR, 0.52; 95% CI, 0.28, 0.97; p = 0.04) were independent factors that were related with less use of abdominal pressure. When only women were considered, the completion rate was lower in the regular group (98.0%, 86.8% and 96.5%, p = 0.04). The use of abdominal pressure was more in the no group than the other 2 groups (56%, 34% and 33%, p = 0.03). When only men were considered, the cecal intubation time was longer in the as-needed group (4.6 +/- 1.4, 4.6 +/- 1.8 and 5.8 +/- 2.5 minutes, p = 0.02). The other outcomes were similar in both genders. The 3 different methods did not result in significantly different completion rates or cecal intubation times. However, activation of the variable stiffness function decreased the need for abdominal pressure. When males and females were considered separately, activation of the variable stiffness function on an as-needed basis in females was the only useful setting.

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

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. 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. Direct comparison through tandem colonoscopies. University endoscopy suite. Forty unselected female patients. Tandem colonoscopies with PVSC and TC. Time to the cecum and the ability to retroflex in the cecum. 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). 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.

Endoscopic Stricturoplasty (ES) of Hepaticojejunostomy Anastomotic Strictures (HAS): A Novel and Effective ERCP Technique

Endoscopic Stricturoplasty (ES) of Hepaticojejunostomy Anastomotic Strictures (HAS): A Novel and Effective ERCP Technique Simon K. Lo, Shahab Mehdizadeh, Gary C. Chen HAS are difficult to treat endoscopically, surgically or transhepatically with a high recurrence rate. Technical failure and treatment complications are common. Aim: To assess the therapeutic efficacy of a new ES technique in the management of HAS. Methods: Retrospective review of ERCP for presumed or confirmed HAS. A pediatric variable stiffness colonoscope or push enteroscope was used except in post-Whipple cases where a therapeutic duodenoscope was favored. SKL introduced the method of ES in 1998 and performed all the procedures. When technically feasible, a guidewire was used to pass a standard sphincterotome to perform ES. Needle knife was used when guidewire access failed. Cutting was done in a 4-quadrant fashion for 4–5 mm each. Balloon dilation was then done with an 8 mm balloon. Stenting was not routinely carried out. Results: Data of 18 patients (mean 51 y.o., range 19–78) suspected of HAS was reviewed. Presentations: cholangitis (50%), abdominal pain (39%), itching (44%), abnormal liver enzymes (89%). Three groups of patients were identified: hepatojejunostomy for lap chole injuries (nZ10), Whipple’s (nZ4), and liver transplantation (nZ4). Symptom duration prior to treatment ranged from 1 month to 10 years (median 6 months). The bilioenteric anastamosis could not be reached in 4 (22%) patients. The remaining 14 patient underwent 18 ERCPs and all had technically successful ES. Needle knife was used in 4 patients. Five early cases included stent placement after sphincterotomy. Stone extraction was performed on 6 patients. 3 patients experienced 4 complications including 2 post-sphincterotomy bleeding (1-self limited; 1-treated endoscopically) and 2 cases of self-limited retroperitoneal air leak. The median follow up period was 15 months (range 0–50 months). Two patients had recurrences or did not improve despite ES and were referred for surgical therapy. Nine had successful ES without need for additional interventions in 20 months (range 4–50 months). 44% (8/18) of all patients remained asymptomatic at last follow up. Conclusions: ES is a novel technique to treat HAS. It is a single-session treatment and it does not require stenting that would mandate repeated procedures. Acquiring the skill is difficult as its prerequisite is successful passage through the long, tortuous afferent jejunal limb. It is reasonably safe and about half of the patients in this study enjoyed long term symptom-free living. T1284 Is Malnutrition a Cause of Post ERCP Cholangitis? Mohandas K. Mallath, Vivek Hande, Mrunal Shirodkar, Shaehta Mehta Background: Cholangitis is a serious complication of endoscopic biliary drainage. Malnutrition predisposes to infection in many clinical settings. This study was done to test a hypothesis that patients with malignant obstructive jaundice (MOJ) develop progressive malnutrition, which predisposes them for ERCP induced cholangitis. Methods: A prospective observational study design was used in the setting of a tertiary cancer center. Consecutive patients with MOJ undergoing endoscopic biliary drainage were eligible. Patients with cholangitis at presentation and those who had undergone ERCP, PTBD or biliary surgery were excluded. All patients were screened for malnutrition 1-2 days before the ERCP using subjective global assessment (SGA). Explanatory variables included bilirubin, albumin, anemia, leucocytosis, coagulopathy, and co-morbid diseases. All patients received antibiotic prophylaxis before ERCP. Other variables included duration of ERCP, proximal biliary obstruction, multiple instrumentation during ERCP, inadequate biliary drainage and type of biliary stent. All patients were followed up for 2 weeks for the development of cholangitis. Cholangitis was defined as the development of fever O100 F for more than 12 hours after an ERCP. Results: 77 patients (45 females, 32 males) aged 27 to 78 years (mean 51 years) were included. The cancer sites included gall bladder (37), pancreas (17), bile duct (13) and others (10). The malnutrition grade were SGA-A (7%), SGA-B (53%) and SGA-C (40%). 25 patients had leucocytosis and 14 had coagulopathy. ERCP was successful in 95%. 4 patients underwent PTBD. 26 (33.8%) patients developed cholangitis. It was mild in 80% and treated with oral antibiotics. 6 needed prolonged hospitalization and 4 needed early stent exchange. One severely malnourished patient developed duodenal perforation, septicemia and died. The cholangitis rates in mild, moderate and severely malnourished patients were 0%, 16% and 51% respectively (p!0.0001). Univariate analysis identified 5 explanatory variables to be associated with cholangitis: leucocytosis, severe malnutrition, proximal biliary obstruction, passage of multiple instruments and the use of plastic stents over metal stents by univariate analysis. In multivariate model, cholangitis was associated with malnutrition (OR 3.5, 95%CI 1.1–11.0) and multiple biliary instrumentation (OR 3.3, 95%CI 1.03– 10.7). Conclusions: Malnutrition is an independent risk factor for ERCP.

Use of Two Methods (Tandem and Consecutive) to Compare Two Tapered Colonoscopes to the Pediatric Variable Stiffness Colonoscope (PVSC) in Female Patients

Use of Two Methods (Tandem and Consecutive) to Compare Two Tapered Colonoscopes to the Pediatric Variable Stiffness Colonoscope (PVSC) in Female Patients

Usefulness of a Small-Caliber, Variable-Stiffness Colonoscope as a Backup in Patients with Difficult or Incomplete Colonoscopy

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. 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. 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. 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.

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.

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. (Gastrointest Endosc 2002;55:172-9.)