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Biomedical subjects

B P Saunders

Publications and source records attributed to B P Saunders.

At least 19 recordsLinked to original sources

The prevalence of small, flat colorectal cancers in a western population.

OBJECTIVE: Small, flat colorectal cancers have been widely reported in the Japanese literature but are thought to occur rarely outside Japan. The aim of this retrospective cohort study was to clarify the prevalence of flat colorectal cancer in a Western population. METHODS: One thousand and twenty-six consecutive colonoscopies performed by a single experienced endoscopist were retrospectively analysed over a two-year period. The morphology, site and histological appearance of all documented colorectal cancers (CRC) were recorded. RESULTS: Forty-seven cases of CRC were detected, five of which (10%) demonstrated flat configuration. Flat cancers varied between 8 and 15 mm in diameter (mean 11 mm). Histologically, all flat lesions were moderately differentiated Dukes A adenocarcinomas. Two of these cancers contained no adenomatous component. CONCLUSION: This study confirms that small, flat colorectal cancers are not an uncommon finding at colonoscopy in Western patients. Compared to polypoid neoplastic lesions, flat cancers appear to undergo malignant change at a smaller size.

Adenocarcinoma↗

Use of multidetector-row CT colonography for detection of colorectal neoplasia in patients referred via the Department of Health "2-Week-wait" initiative.

AIM: Patients referred under the Department of Health 2-week wait initiative with symptoms of colorectal cancer frequently undergo whole-colon examination. We investigated the use of computed tomography (CT) colonography as an alternative to colonoscopy in this scenario. MATERIALS AND METHODS: Fifty-four consecutive patients, referred via the 2-week wait initiative and scheduled for colonoscopy, consented to undergo multidetector CT colonography immediately before endoscopy. The site and morphology of any polyp or cancer detected by CT was noted and comparison made with subsequent colonoscopy. RESULTS: Colonoscopy detected polyps or cancer in 29 patients (53.7%). CT colonography prospectively detected 18 of 41 (44%) polyps of 1-5 mm, three of four (75%) polyps of 6-9 mm, four of four (100%) polyps 10 mm or larger, and five of six (83%) cancers. The missed cancer occurred early in the series and was a perceptive error. The overall sensitivity, specificity, positive predictive value and negative predictive value of CT colonography for cancer and polyps 10 mm or greater on a per patient basis were 90, 100, 100 and 98%, respectively. CT detected one renal cancer and one colonic cancer, initially missed due to incomplete colonoscopy. CONCLUSION: CT colonography is a robust technique for investigation of symptomatic patients. The learning curve must be overcome for optimal performance.

Adult↗

Long-acting steroid injection after endoscopic dilation of anastomotic Crohn's strictures may improve the outcome: a retrospective case series.

BACKGROUND AND STUDY AIMS: Endoscopic balloon dilation of Crohn's strictures is widely practised, but may not result in long-term symptomatic benefit, leading to the need for repeat dilation or surgery. It is hypothesized that long-acting steroid injection into strictures after dilation may decrease the need for further stricture dilation and improve the outcome in symptomatic patients. PATIENTS AND METHODS: Patients with Crohn's disease who have had balloon dilation and triamcinolone injection performed for symptomatic anastomotic strictures were identified from endoscopy records. Case notes were reviewed to determine outcomes. RESULTS: Fourteen patients underwent a total of 26 dilations, with triamcinolone injected (median dose 20 mg, 10-40 mg) in 20 of the procedures. Seven patients (50%) had sustained remission after a single dilation and steroid injection, with a median follow-up period of 16.4 months (range 13.2-22.0 months). Four patients (28.5%) required more than one dilation (median three dilations, range two to four) to control their symptoms, with a median follow-up period of 27.8 months (range 14-32.8 months). Endoscopic management failed in three patients (21.4 %), who were referred for surgery. There were no complications due to dilation or triamcinolone injection. CONCLUSIONS: Triamcinolone injection into the stricture after dilation is safe, easy to perform, and may be a useful adjunct in the management of anastomotic Crohn's strictures. These data will require further support through a randomized and controlled trial.

Aged↗

Effect of real-time magnetic endoscope imaging on the teaching and acquisition of colonoscopy skills: results from a single trainee.

BACKGROUND AND STUDY AIMS: Most trainees have little concept of the loops that occur during colonoscopy, and have difficulty in appreciating the combination of withdrawal and torquing manoeuvres that are essential to achieving complete colonoscopy. Real-time magnetic endoscope imaging (MEI) allows visualization of shaft looping, and so makes intuitive the manoeuvres necessary to straighten the colonoscope shaft. PATIENTS AND METHODS: Consecutive routine colonoscopies were performed by a single trainee (with previous experience of 15 colonoscopies). Procedures were randomly assigned to be carried out either with the trainee viewing the MEI display, or without the MEI view, which was recorded throughout all examinations. RESULTS: In total, 71 procedures were performed. To assess the trend for learning, procedures were analysed in blocks of 24 consecutive examinations (periods 1 to 3). In the first 24 procedures (period 1), the number of attempts at straightening the colonoscope and duration of looping were significantly less, and the intubation time was shorter, for examinations performed with the MEI view. In periods 2 to 3, there was a continued trend towards improved performance, but without a significant difference between procedures performed with or without MEI. CONCLUSIONS: During training, real-time colonoscope imaging using MEI appears to enhance the endoscopist's appreciation of looping and improves the learning of the manoeuvres required to straighten the colonoscope shaft. A prospective, multicentre study assessing a larger number of trainees is needed to clarify these findings.

Adult↗

A prospective study of the technical feasibility of ileoscopy at colonoscopy.

BACKGROUND: Despite a well-documented diagnostic yield, ileoscopy at colonoscopy is not performed routinely. This is due to the perceived difficulty in intubating the ileocaecal valve, added procedure time and a lack of acceptance regarding diagnostic yield. Therefore, we conducted a study to investigate the technical feasibility of ileoscopy at colonoscopy. METHODS: Ileoscopy was studied prospectively in 120 patients undergoing diagnostic colonoscopy. After identification of the caecum, ileoscopy was attempted by one of four techniques. The time taken to pass from caecum to terminal ileum, the patient position, use of Hyoscine-n-butyl bromide and any ileal abnormalities were recorded in each case. RESULTS: Ileoscopy was successful in 117/120 (97%) cases with a median time of 55 s taken to intubate the ileo-caecal valve. A 'down and left' technique was used in most cases (74.4%). Switching the patient to supine aided ileoscopy in 24 cases (20.4%) and Hyoscine-n-butyl bromide was considered helpful in 25 (21.4%). Overall, the terminal ileum was abnormal in 24 of 117 (20.5%) patients. CONCLUSIONS: Ileoscopy can be achieved in nearly all patients undergoing diagnostic colonoscopy and the added procedure time is short. Added time, technical difficulty and limited yield are not valid reasons for choosing not to perform ileoscopy.

Abdominal Pain↗

Endoscopic resection of large sessile colonic polyps by specialist and non-specialist endoscopists.

BACKGROUND: Patients with large sessile colonic polyps for which endoscopic resection might be feasible are often referred directly for operation. The aim of this study was to determine the outcome of patients with such polyps diagnosed by specialist and non-specialist colonoscopists. METHODS: Patients with large (greater than 2 cm) sessile polyps detected at colonoscopy from January 1995 to July 2000 were identified. Resection technique and clinical and endoscopic outcomes were recorded. Two of the colonoscopists (B.P.S., C.B.W.) are recognized as specialists. RESULTS: Some 130 polyps were identified, 100 detected by either of two specialist endoscopists (including 14 cancers) and 30 by 14 non-specialist endoscopists (including ten cancers). Endoscopic resection of benign polyps was attempted by experts in 80 (93 per cent) of 86 cases and by non-experts in 15 of 20 cases (P = 0.03), with successful management by endoscopy alone in 61 (76 per cent) of 80 and in six of 15 cases respectively (P = 0.01). Complications occurred following three polypectomies performed by an expert (bleeding, two; pain, one) and one by a non-expert (bleeding). The estimated end-cost of management by specialists was less than half of that by non-specialists. CONCLUSION: Endoscopic resection of large sessile colonic polyps is feasible in the majority of patients and should be considered as first-line therapy. Prompt referral to a specialist endoscopist may improve outcomes by avoiding operation or enabling complete excision at a single endoscopy session.

Adult↗

Patient pain during colonoscopy: an analysis using real-time magnetic endoscope imaging.

BACKGROUND AND STUDY AIMS: Colonoscopy is generally perceived as being a painful procedure. Contributory factors are: stretching of the colonic wall and mesenteric attachments from looping of the instrument shaft, overinsufflation, the degree of torque or force applied to the colonoscope shaft, and patient pain threshold. The aim of this study was to determine the frequency of pain episodes experienced during diagnostic colonoscopy and the corresponding colonoscope configuration, utilizing real-time magnetic endoscope imaging (MEI). PATIENTS AND METHODS: Consecutive outpatients undergoing colonoscopy were studied. Patients with previous colonic resections were excluded. Procedures were commenced with antispasmodics only, and patient sedation was self-administered whenever significant discomfort was experienced, using a patient-controlled analgesia (PCA) syringe pump. All "demands" were correlated with the MEI record, which was subsequently analysed. RESULTS: A total of 650 demands were recorded in 102 patients. Seventy-seven percent of all demands occurred with the colonoscope tip in the sigmoid colon, 7 % in the descending colon, 6 % at the splenic flexure, 5 % in the transverse colon, and 4 % in the proximal colon. Ninety percent of all pain episodes coincided with either looping (79 %) or straightening of the colonoscope shaft (11 %); presumed overinsufflation being an infrequent cause of pain (9 %). Of the loops encountered during colonoscopy, the N-sigmoid spiral loop was associated with the majority of pain episodes (56 %). Looping was both more frequent ( P = 0.0002) and less well tolerated in women than in men ( P = 0.0140). CONCLUSIONS: This study is the first to document pain at colonoscopy accurately. Looping, particularly in the variable anatomy of the sigmoid colon, is the major cause of pain, especially in women. Use of MEI may improve pain control by facilitating the straightening of loops within the sigmoid colon, and by enabling the endoscopist to target patient analgesia.

Analgesics↗

Magnetic endoscope imaging: a new technique for localizing colonic lesions.

BACKGROUND AND STUDY AIMS: The precise localization of advanced colorectal lesions preoperatively directs the appropriate surgical management. The use of internal landmarks at colonoscopy can be inaccurate, and other methods are therefore necessary to localize lesions precisely. Magnetic endoscope imaging (MEI), a real-time, nonradiographic technique for imaging of the colonoscope, may assist in determining the location of lesions found at colonoscopy. PATIENTS AND METHODS: A prospective study was carried out to determine the accuracy of MEI for localizing the colonoscope tip anatomically. The MEI system was used to identify one of four predetermined locations within the colon. Once identified, two endoscopic marking clips were attached to the colonic mucosa, and 400 - 500 ml of Urografin radiographic contrast medium was injected to produce an air-contrast "enema." The clips were subsequently localized using plain abdominal radiography, assessed by a single experienced radiologist who was blinded to the colonoscopic findings. RESULTS: Twenty-nine consecutive patients were enrolled in the study. The overall accuracy of MEI in comparison with the air-contrast "enema" was 90 % (26 of 29 cases). There were three slight errors of localization - clips localized to the descending rather than the sigmoid-descending colon junction (n = 1), or to either side of the mid-transverse (n = 1) and hepatic flexure (n = 1) - but these were not considered to be of surgical or clinical importance. CONCLUSIONS: MEI is a reliable and accurate method for determining the anatomical position of the endoscope tip during colonoscopy. When it becomes commercially available, we believe the use of MEI will avoid the need for unnecessary barium enemas for localization of lesions prior to definitive surgery.

Colonic Neoplasms↗

Duodenal cancer in patients with familial adenomatous polyposis (FAP): results of a 10 year prospective study.

BACKGROUND: Duodenal cancer is one of the leading causes of death in familial adenomatous polyposis (FAP) patients. An endoscopic surveillance programme was therefore initiated in 1988, the outcome of which is described in this paper. METHODS: We report the 10 year follow up of 114 patients with FAP who were prospectively screened for the presence and severity of duodenal adenomas. RESULTS: Six of 114 patients (median age 67 years) developed duodenal adenocarcinoma. Four of these were from 11 patients who originally had Spigelman stage IV disease (advanced duodenal polyposis), which gives a 36% risk within this group of developing cancer. One case of duodenal cancer arose from 41 patients who originally had stage III disease (2%) and one cancer arose from 44 patients with original stage II disease (2%). All six patients have died: five were inoperable and one had recurrence three years after a pancreaticoduodenectomy. There was no association between duodenal cancer and site of germline mutation of the APC gene. CONCLUSIONS: Surveillance for duodenal adenocarcinoma and subsequent early referral for curative surgery has not been effective. Selection of patients with advanced but benign (Spigelman stage IV) duodenal polyposis for prophylactic pancreaticoduodenectomy should therefore be considered and can now be justified on the basis of these results. More comprehensive endoscopic surveillance of high risk (stage III and IV) patients is needed in an attempt to avoid underestimating the severity of duodenal polyposis, and to evaluate the role of endoscopic therapy in preventing advanced disease.

Adenocarcinoma↗

A randomised, double blind, placebo controlled study of celecoxib, a selective cyclooxygenase 2 inhibitor, on duodenal polyposis in familial adenomatous polyposis.

BACKGROUND: Non-selective cyclooxygenase (COX) inhibitors (non-steroidal anti-inflammatory drugs) inhibit large bowel carcinogenesis in patients with familial adenomatous polyposis (FAP). Their role in the duodenum of these patients is less certain. The disease modifying activity of specific COX-2 inhibitors has not been explored in humans. PATIENTS AND METHODS: This was a randomised, double blind, placebo controlled study of celecoxib (100 mg twice daily (n=34) or 400 mg twice daily (n=32)) versus placebo (n=17), given orally twice daily for six months to patients with FAP. Efficacy was assessed qualitatively by blinded review of shuffled endoscopy videotapes comparing the extent of duodenal polyposis at entry and at six months and quantitatively by measurement of the percentage change in duodenal area covered by discrete and plaque-like adenomas from photographs of high and low density polyposis. RESULTS: Shuffled and blinded video review showed a statistically significant effect of 400 mg twice daily celecoxib compared with placebo treatment (p=0.033) with all five independent observers scoring a beneficial effect. Overall, patients taking celecoxib 400 mg twice daily showed a 14.5% reduction in involved areas compared with a 1.4% for placebo (p=0.436). However, patients with clinically significant disease at baseline (greater than 5% covered by polyps) showed a 31% reduction in involved areas with celecoxib 400 mg twice daily compared with 8% on placebo (p=0.049). CONCLUSIONS: A panel of five endoscopists found a significant reduction in duodenal polyposis after six months of treatment with celecoxib 400 mg twice daily. COX-2 inhibition may help this otherwise untreatable condition.

Adenomatous Polyposis Coli↗

Twin-endoscope scissors resection (T-ESR): a new minimally invasive technique for performing colonic mucosectomy.

BACKGROUND: Piecemeal resection is currently the safest method for the endoscopic removal of large sessile colonic polyps. However, this method has its limitations, including the quality of the specimen received for histopathology and the need for early follow-up due to the possibility of incomplete resection and recurrence. New methods enabling en bloc resection would be advantageous in these respects. METHODS: We developed a new technique that uses endoscopic scissors and two endoscopes to perform mucosal resection in a porcine model. So far, the technique has been evaluated in two animals. RESULTS: The resection of intact mucosal specimens measuring 1.5 x 1 cm and 2.2 x 3.5 cm was achieved, with no procedural or late hemorrhage and no clinical or radiological evidence of perforation. CONCLUSION: After further development and evaluation, this technique should be suitable for the resection of large sessile colonic polyps in humans.

Animals↗

Effect of magnetic endoscope imaging on colonoscopy performance: a randomised controlled trial.

BACKGROUND: Colonoscopy can be technically challenging because of unpredictable colonoscope looping. Without imaging, straightening the colonoscope is sometimes difficult since the endoscopist has to guess where the tip is. Magnetic endoscope imaging (MEI), a new non-radiographical technique for picturing the colonoscope shaft in real time, could facilitate loop straightening and thus improve performance. METHODS: We assessed trainees and endoscopists with much experience of routine outpatient colonoscopy. In group 1, trainees examined 113 consecutive patients. MEI views were recorded in all examinations, but procedures were randomised to be done by two trainees, either with the endoscopist and endoscopy assistants viewing the imager display (n=58), or without the imager view (n=55). In group 2, two skilled endoscopists were randomised (as with group 1) to undertake consecutive examinations (n=183) either with (n=92) or without (n=91) the MEI view. MEI views of all procedures were analysed retrospectively. FINDINGS: In both groups, intubation times were shorter (median 11.8 min [4.3-31.5] vs 15.3 min [4-67] [group 1]; 8.0 min [2.6-40.8] vs 9.3 min [2.5-52.6] [group 2]) and number of attempts at straightening the colonoscope fewer (median 5 [0-20] vs 12 [0-57] [group 1]; 7 [0-55] vs 10 [0-80] [group 2]), when the endoscopist was able to see the imager view. In group 1, colonoscopy completion rates were also higher (100% [58] vs 89% [49]) and duration of looping was reduced (median 3 min [0-18.8] vs 5.4 min [0-44.5]) when the imager could be seen. Abdominal hand pressure was more effective when the endoscopist and endoscopy assistant could see the imager view. INTERPRETATION: MEI significantly improves performance of colonoscopy, particularly when used by trainees, or by experts in technically difficult cases; loops were straightened or controlled effectively, resulting in quick intubation times and high completion rates.

Adolescent↗

Endoscopic management of polypoid early colon cancer.

Endoscopic management of polypoid early colonic cancer (malignant polyps and polypoid carcinomas) is no longer controversial. When the endoscopist is satisfied that excision is complete and histology is "favorable" (a resection margin of 2 mm and well or moderately well differentiated tumor), surgery is unnecessary. When histology show "unfavorable" characteristics (which a few histologists still take to include invasion into lymphatics), surgical or laparoscopic resection may be indicated, providing the patient is considered at suitable risk. Surgery kills some patients without finding residual cancer and cannot save others with metastases, so it should be recommended only with due clinical consideration. Sessile or broad-based polyps, especially those in the rectum, are more likely to be "high risk" and merit specialist management if local removal is to be attempted and to allow proper histologic assessment. Endoscopic approaches such as saline injection polypectomy, india-ink tattooing, and use of the argon beam coagulator are applicable in some cases. New approaches that still require trials include ultrasonographic probes, which occasionally clarify the degree of invasion, and prototype stapling devices to allow full-thickness histologic specimens to be obtained.

Colonic Polyps↗

Development of colonoscopy teaching simulation.

After 17 years of prototyping, a first release version of the St Mark's Hospital teaching simulator is in final preparation. Advances in computer processing power and graphics cards make it possible to achieve real-time processing of colon and endoscope characteristics and a simulated endoscopic view at an acceptable cost. Realistic feel or "force feedback" for all instrument controls and shaft movements is incorporated. To make the simulator more than a "video game", a package of teaching and assessment features is to be incorporated, including interactive animated graphics to explain particular endoscope loops and situations and the variations of colonic anatomy that are typically encountered. Simulation should spare patients from being used for the early phases of training and should speed up and quantify the learning process. Simulators may introduce even experienced endoscopists to some of the advanced options available in current or future endoscopes or accessories, as well as the use of imminent new technology such as the magnetic imaging system.

Colonoscopy↗