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PubMed2003

Validation of a computer-based colonoscopy simulator.

BACKGROUND: The computer-based colonoscopy simulator is intended to provide a realistic colonoscopic experience and feedback to operators regarding procedure skills. Advocates hope that computer-based colonoscopy simulators will enhance the mastery of colonoscopy by trainees. Before this hypothesis can be tested, the claims made for a simulator must be validated. The aims of this study were to answer the following: Does a computer-based colonoscopy simulator provide a "realistic" experience? Do computer-based colonoscopy simulators' performance parameters differentiate varying levels of experience? METHODS: Ten staff gastroenterologists, 6 gastroenterology fellows, and 6 residents each performed 2 computer-based colonoscopy simulator colonoscopies and performance parameters were recorded. Staff colonoscopists then completed a 6-item survey grading the "realism" of the simulation and procedure difficulty. Survey responses and performance scores were compared with the Wilcoxon rank-sum test. RESULTS: Faculty found the computer-based colonoscopy simulator experience to be realistic despite the "cases" being markedly easier than actual colonoscopy. The computer-based colonoscopy simulator distinguishes subjects according to endoscopic experience with 3 of its measured parameters (total procedure time, insertion time, time in "red-out"). No significant difference in the ability to distinguish among user types was found for the other 10 computer-based colonoscopy simulator measurements for which data were analyzable. CONCLUSION: The computer-based colonoscopy simulator provides a favorable degree of virtual realism with regard to visual simulation and colonoscope mechanics, although the "cases" were regarded as considerably easier than actual colonoscopy. The computer-based colonoscopy simulator has only limited capability for distinguishing varying levels of competence at actual colonoscopy. These findings suggest that a study to determine the role of computer-based colonoscopy simulators in the curriculum of trainees is warranted.

Clinical Competence↗

PubMed2000

Factors predicting the possibility of conducting colonoscopy without sedation.

BACKGROUND AND STUDY AIMS: Colonoscopy without sedation costs less than sedated colonoscopy. The aims of the present study were to determine the percentage of patients who can successfully undergo nonsedated colonoscopy and to identify factors capable of predicting whether a colonoscopy can be completed without sedation. PATIENTS AND METHODS: Demographic, clinical, and colonoscopy-related data were prospectively recorded for consecutive patients undergoing colonoscopy by an experienced endoscopist in a single private practice setting. All of the colonoscopies routinely began without sedation, unless sedation was specifically requested by the patient. Sedation was given when requested by the patient if significant discomfort occurred during the procedure. To determine factors making it more likely that nonsedated colonoscopy would be possible, age, sex, presence of diverticulosis, prior colonic surgery, prior colonoscopy, and the time required to complete the colonoscopy were evaluated using a multivariate logistic regression analysis. RESULTS: Five patients asked to have sedation before the procedure. Of 173 patients in whom colonoscopy was started without sedation, 159 (91.9%) required no sedation. Complete colonoscopy was achieved in 152 of the 173 initially nonsedated patients (87.9%) and in 167 of the total of 178 patients (93.8%). Multivariate logistic regression analysis showed that male sex (odds ratio 5.9; 95% CI, 1.7 to 21.4) and a prior segmental colonic resection (odds ratio 6.2; 95% CI, 0.8 to 48.9) were associated with an ability to complete the colonoscopy procedure without sedation. CONCLUSIONS: The vast majority of patients undergoing colonoscopy procedures conducted by an experienced endoscopist do not require sedation. Male sex, segmental colonic resection, and probably experience in lower gastrointestinal endoscopy on the part of the patient, are predictive factors for successful colonoscopy without sedation.

Adolescent↗

PubMed2004

Reasons for failure to diagnose colorectal carcinoma at colonoscopy.

BACKGROUND AND STUDY AIMS: Colonoscopy can produce false-negative results, and the reasons for this remain obscure. The aim of this study was to examine why cancers are missed at colonoscopy. PATIENTS AND METHODS: All colonoscopies carried out at Christchurch Hospital, New Zealand, over a 43-month period (1 October 1997 - 30 April 2001) were retrospectively analyzed (the data having been prospectively collected). All cases of colorectal carcinoma during the period 1 October 1997 - 30 July 2001 (3 months longer, to capture delayed diagnoses) were also identified. The two databases were then compared, and all cases in which a colonoscopy had been performed more than 6 weeks before a colorectal carcinoma specimen being received by the pathology department were identified and analyzed. RESULTS: A total of 5055 colonoscopies were undertaken in 4598 patients. Over this period, 630 colorectal carcinomas were identified in the pathology database; 286 of the patients affected were in the colonoscopy and pathology database. Sixty-six patients had had a colonoscopy performed more than 6 weeks before the diagnosis of colorectal carcinoma. Carcinoma was identified in 48 of these 66 patients, and management was being provided. Seventeen cancers (5.9 %) were missed at colonoscopy, and the patients had had an incomplete colonoscopy in nine of these cases. In seven of the 17, an alternative benign cause was recorded. In four patients, a lesion was seen and thought to be benign, although subsequently proven not to be. In another four cases, the cancer was not diagnosed despite adequate bowel preparation and what was thought by the colonoscopist to be an adequate colonoscopy. CONCLUSIONS: Colonoscopy missed 17 of 286 cancers (5.9 %). The reasons why cancers were missed relate to incomplete colonoscopy, poor bowel preparation, misinterpretation of what was seen, failure to carry out adequate biopsy (and follow-up) of lesions seen, and systems failures related to follow-up investigations in patients who had an incomplete colonoscopy. The fact that colonoscopy and barium enema investigations may fail to diagnose cancers has important medicolegal implications. The recognition that colonoscopy may miss a cancer should encourage doctors to reinvestigate patients when there is a lack of correlation between the clinical and investigative findings.

Aged↗

PubMed2003

Computed tomographic virtual colonoscopy to screen for colorectal neoplasia in asymptomatic adults.

BACKGROUND: We evaluated the performance characteristics of computed tomographic (CT) virtual colonoscopy for the detection of colorectal neoplasia in an average-risk screening population. METHODS: A total of 1233 asymptomatic adults (mean age, 57.8 years) underwent same-day virtual and optical colonoscopy. Radiologists used the three-dimensional endoluminal display for the initial detection of polyps on CT virtual colonoscopy. For the initial examination of each colonic segment, the colonoscopists were unaware of the findings on virtual colonoscopy, which were revealed to them before any subsequent reexamination. The sensitivity and specificity of virtual colonoscopy and the sensitivity of optical colonoscopy were calculated with the use of the findings of the final, unblinded optical colonoscopy as the reference standard. RESULTS: The sensitivity of virtual colonoscopy for adenomatous polyps was 93.8 percent for polyps at least 10 mm in diameter, 93.9 percent for polyps at least 8 mm in diameter, and 88.7 percent for polyps at least 6 mm in diameter. The sensitivity of optical colonoscopy for adenomatous polyps was 87.5 percent, 91.5 percent, and 92.3 percent for the three sizes of polyps, respectively. The specificity of virtual colonoscopy for adenomatous polyps was 96.0 percent for polyps at least 10 mm in diameter, 92.2 percent for polyps at least 8 mm in diameter, and 79.6 percent for polyps at least 6 mm in diameter. Two polyps were malignant; both were detected on virtual colonoscopy, and one of them was missed on optical colonoscopy before the results on virtual colonoscopy were revealed. CONCLUSIONS: CT virtual colonoscopy with the use of a three-dimensional approach is an accurate screening method for the detection of colorectal neoplasia in asymptomatic average-risk adults and compares favorably with optical colonoscopy in terms of the detection of clinically relevant lesions.

Adenoma↗

PubMed2005

Sedation-free colonoscopy.

PURPOSE: The administration of sedative drugs at colonoscopy has its drawbacks, such as increasing the rate of complications and the cost. There are a number of potential advantages to performing colonoscopy without sedation. The aim of this study is to evaluate patient tolerance and acceptance during sedation-free colonoscopy. METHODS: Pain during sedation-free colonoscopy was evaluated in consecutive series of 675 patients in a prospective manner from January 1, 2003, to February 18, 2004. We recorded the degree of patient pain during colonoscopy, willingness to undergo sedation-free colonoscopy in the future, the complication rate, and the intubation time. The assisting endoscopy nurses and patients independently assessed the pain level immediately after the procedure using a four-point pain scale (nil, mild, moderate, severe). RESULTS: Almost all colonoscopies (99.6 percent: 672/675) were successful. There were four complications related to colonoscopy (bleeding after polypectomy). Patients and nurses rated pain by a four-point pain scale as follows. For the patients: nil, 69.6 percent (470/675); mild, 28.0 percent (189/675); moderate, 2.2 percent (15/675); severe, 0.1 percent (1/675). For the nurses: nil, 76.1 percent (514/675); mild, 22.7 percent (153/675); moderate, 0.9 percent (6/ 675); severe, 0.3 percent (2/675). Patients rarely suffered from severe pain during carefully performed colonoscopies. The pain level of almost all colonoscopies was acceptable by patients, with only six patients (1.0 percent) stating that they would never undergo a colonoscopy without sedation in the future because of unbearable pain. CONCLUSIONS: This study suggests that carefully performed sedation-free colonoscopy rarely causes complications and is well accepted by most patients. Sedation-free colonoscopy is more cost-effective, may be safer, and should be offered as an alternative to colonoscopy with sedation.

Adolescent↗

PubMed2005

Utilization of colonoscopy in the United States: results from a national consortium.

BACKGROUND: To assess capacity for colonoscopy, we need to understand current utilization of colonoscopy in diverse clinical practice settings. The objective of this study was to determine the utilization of colonoscopy in diverse clinical practice settings. METHODS: The Clinical Outcomes Research Initiative (CORI) data repository, which receives endoscopy reports from 73 diverse adult practice sites in the United States was used. Colonoscopy reports from January 2000 to August 2002 were analyzed to determine the demographic characteristics of adult patients who received a colonoscopy and the procedure indication. The relationship of age, race, gender, and procedure indication was analyzed. RESULTS: Results of colonoscopies in 146,457 unique patients were analyzed. Of the reports, 68% came from nonacademic settings. Patients less than 50 years of age accounted for 20% of colonoscopies. The most common indications were rectal bleeding (33.6%), irritable bowel symptoms (23.8%), or screening because of a positive family history of colorectal cancer (22.4%) and screening with a primary colonoscopy or a fecal occult blood test (FOBT) (12.8%). In patients 50 years and older, asymptomatic screening (average-risk screening colonoscopy, positive family history, or FOBT positivity) accounted for 38.1% of all colonoscopies. Surveillance colonoscopy in patients with previous cancer or polyps accounted for 21.9% of colonoscopies performed in this age group. Differences in utilization were noted, based on gender and race. CONCLUSIONS: Colonoscopy utilization varies based on age, gender, and race. Colonoscopy often is performed in patients less than 50 years old for irritable bowel symptoms; rectal bleeding; or average-risk screening, for which benefits are uncertain. In patients older than 50 years, surveillance after polyp removal is a common indication and may be overused. Understanding utilization can lead to further study to determine outcomes, to optimize utilization, and to provide a basis for shifting limited resources.

Aged↗

PubMed2000

The introduction and development of colonoscopy within a defined population in Sweden.

BACKGROUND: Our aim was to describe, in a population-based setting, the use of colonoscopy over time with special emphasis on indications, the competence of the endoscopists, and the frequency of total colonoscopies and to compare the number of colonoscopies with that of barium enemas. METHODS: All colonoscopy records during 1979-95 in a Swedish county (population, 258,000) were retrieved. Information was collected about the patients' demographics, the endoscopists, indications, findings, and type of colonoscopy. RESULTS: A total of 6066 colonoscopies were performed in 4304 patients by 62 endoscopists. Of these, 562 were not intended to be complete; of the other 5504 colonoscopies, 4153 were complete (75%). Of the patients 77% had undergone colonoscopy once, 14% twice, and 9% three times or more. Among the endoscopists 73% never performed more than 50 colonoscopies, and 5% did more than 700 colonoscopies. Bleeding as an indication increased from 10% to 31%; polyps decreased from 30% to 10%, and unclear X-ray findings decreased from 28% to 4%. Diarrhoea and abdominal pain, both 0% in 1979, increased to 6% and 5%, respectively. Surveillance (cancer, polyps, colitis) was fairly stable, at 25%. Both the rate of complete colonoscopies and the proportion of colonoscopies done by experienced endoscopists increased with time. The annual number of barium enemas was relatively constant until 1992 but then decreased. CONCLUSIONS: The increased use of colonoscopy has resulted in a decrease in barium enemas. The competence of the endoscopists increased, resulting in a higher rate of complete colonoscopies.

Adolescent↗

PubMed2004

High compliance rates observed for follow up colonoscopy post polypectomy are achievable outside of clinical trials: efficacy of polypectomy is not reduced by low compliance for follow up.

INTRODUCTION: The National Polyp Study demonstrated that removal of adenomas with at least a three-year follow up reduced the incidence of colorectal cancer. However, compliance with follow up colonoscopy may affect the estimates of reduction in colorectal cancer incidence demonstrated by the National Polyp Study. While an 80% compliance rate for follow up colonoscopy was achieved during the National Polyp Study, the compliance rate for follow up colonoscopy is unknown in the general population. The aim of this study was to determine the compliance rate for follow up colonoscopy and factors which affect follow up. METHODS: A retrospective medical record review to identify patients who had adenomatous polyps excised in 1997 was undertaken. Patients who had inflammatory bowel disease, a prior history of colorectal cancer, familial adenomatous polyposis syndrome, colonic surgery; incomplete polypectomy or incomplete colonoscopy, and those patients who died before planned follow up, were excluded from analysis. Follow up was performed by telephone survey. RESULTS: Three hundred and thirty-three patients were identified (196 males; 147 females) with a mean age of 70 years. Three hundred and thirty-one (99%) of 333 had a documented recommendation for follow up of three years or less. Thirty-four percent (113 of 333) had previously undergone colonoscopy; 29% (98 of 333) had previously undergone polypectomy and 54% (180 of 333) were symptomatic at the time of the colonoscopy. Twenty-eight percent (40 of 141) had a family history of colorectal cancer. Pathology at polypectomy included a single polyp and polyps less than 10 mm in 68% and 88% of cases, respectively. Follow up was available in 211 of these cases, 179 (85%) of which had been compliant with follow up colonoscopy. In a univariate analysis, previous colonoscopy (P = 0.035), previous polyps (P = 0.043), asymptomatic status at time of colonoscopy (P = 0.021), polyp size (P = 0.008) and number of polyps (P = 0.010) were significantly associated with patients who were compliant with follow up colonoscopy. A multivariate logistics regression analysis revealed number of polyps (P = 0.036) and polyp size (P = 0.045) to be statistically significantly associated with compliance. CONCLUSION: Compliance with follow up colonoscopy after polypectomy is greater than 80%, regardless of age, education, family history, prior colonoscopy, or prior polypectomy. Risk reduction published in the National Polyp Study may likely reflect what can be achieved through the general use of colonoscopy for surveillance.

Adenomatous Polyps↗

PubMed2006

Does a negative screening colonoscopy ever need to be repeated?

BACKGROUND AND AIMS: Screening colonoscopy is thought to be a powerful and cost-effective tool to reduce colorectal cancer incidence and mortality. Whether and when colonoscopy with negative findings has to be repeated is not well defined. The aim of this study was to assess the long term risk of clinically manifest colorectal cancer among subjects with negative findings at colonoscopy. PATIENTS: 380 cases and 485 controls participating in a population based case-control study in Germany. METHODS: Detailed history and results of previous colonoscopies were obtained by interview and from medical records. Adjusted relative risks of colorectal cancer among subjects with a previous negative colonoscopy compared with those without previous colonoscopy were estimated according to time since colonoscopy. RESULTS: Subjects with previous negative colonoscopy had a 74% lower risk of colorectal cancer than those without previous colonoscopy (adjusted odds ratio (aOR) = 0.26 (95% confidence interval, 0.16 to 0.40)). This low risk was seen even if the colonoscopy had been done up to 20 or more years previously. Particularly low risks were seen for sigma cancer (aOR = 0.13 (0.04 to 0.43)) and for rectal cancer (aOR = 0.19 (0.09 to 0.39)), and after a negative screening colonoscopy at ages 55 to 64 (aOR = 0.17 (0.08 to 0.39)) and older (aOR = 0.21 (0.10 to 0.41)). CONCLUSIONS: Subjects with negative findings at colonoscopy are at very low risk of colorectal cancer and might not need to undergo repeat colonoscopy for 20 years or more, if at all. The possibility of extending screening intervals to 20 years or more might reduce complications and increase the feasibility and cost-effectiveness of colonoscopy based screening programmes.

Adult↗

PubMed2001

A prospective analysis of 13,580 colonoscopies. Reevaluation of credentialing guidelines.

BACKGROUND: The aims of this study were to assess the safety and efficacy of surgeons performing colonoscopy, and to use the results to reevaluate currently available credentialing guidelines. METHODS: A prospective outcomes study was designed to include all members of the Society of American Gastrointestinal Endoscopic Surgeons (SAGES). End points were related to the efficacy and safety of colonoscopy. Credentialing guidelines were reviewed. RESULTS: Between April 1998 and September 1999 13,580 colonoscopies were prospectively entered into a database. The most common indications were rectal bleeding, colonic polyps, and change in bowel habits. The colonoscopy was normal or revealed only diverticulosis or nonspecific inflammation in 8,473 (62.4%), lower gastrointestinal bleeding in 4 (0.03%), polyps in 4,645 (34.2%), and tumors in 458 (3.4%) patients. The most common biopsy methods for polyps or tumors were the snare (n = 1,728; 34%), the hot (n = 1,600; 31%), and the cold (n = 1,340; 22%) procedures. The colonoscopy was complete in 12,495 cases (92%), requiring a mean procedure time of 22.7 min (range, 1-170 min). Intraprocedural complications included arrhythmia (n = 14; 0.1%), bradycardia (n = 115; 0.8%), hypotension (n = 171; 1.2%), and hypoxia (n = 806; 5.6%). Postprocedural complications were seen in 27 patients (0.2%). Bleeding (n = 10; 0.07%) was managed by observation alone (n = 9; 0.06%) and repeat colonoscopy with transfusion (n = 1; 0.01%). Perforation (n = 10; 0.07%) was treated successfully by observation with conservative management (n = 5; 0.05%) and surgery (n = 5; 0.05%); severe abdominal pain (n = 4; 0.03%) was managed by observation and conservative therapy; and bronchospasm (n = 2; 0.015%) was managed by observation and supportive care. One single mortality (0.007%) was that of a 70-year-old man with a massive lower gastrointestinal hemorrhage who had a cardiac arrest in the recovery room following colonoscopy. The complication rate was not significantly associated statistically with either the level of experience or the number of prior or annual colonoscopies. However, prior colonoscopic experience did have an impact on the completion rate (p < 0.001) and was inversely proportional to the time to completion (p < 0.001). Similarly, the number of annual colonoscopies affected the completion rate and was inversely correlated with the time to completion (p < 0.001). CONCLUSIONS: This large prospective outcomes study showed that colonoscopy performed by surgeons can be rapidly and successfully done with acceptably low morbidity and mortality. There was no association between experience and complications. However, a minimum of 50 prior colonoscopies and 100 annual colonoscopies were associated with a significant improvement in the rate of completion. There was also a significant correlation between both prior and ongoing annual experience and the time required for the examination. No minimum number of cases can be mandated for credentialing to perform "safe" colonoscopies.

Clinical Competence↗

PubMed2006

The importance of colonoscopy in colorectal surgeons' practices: results of a survey.

PURPOSE: The role of colonoscopy in the prevention of colorectal cancer has been accepted, not only by the medical community but by the federal government as well. This study sought to document the current role of colonoscopy in the practices of colorectal surgeons. METHODS: A survey was mailed to members of The American Society of Colon and Rectal Surgeons detailing the scope of colonoscopy in their practices. RESULTS: Surveys were mailed to 1,800 members of The American Society of Colon and Rectal Surgeons; responses were received from 778 (43.2 percent). The mean age was 48 +/- 10 (range, 27-79) years; the mean number of years in practice was 14 +/- 10 (range, 0.2-48). The majority of respondents (91 percent) were male. Responses were received from 47 U.S. states and 30 foreign countries. Seventy-four respondents (9.5 percent) reported not performing colonoscopy; the most common reason cited was "referring physicians' preference" (45 percent). Seven-hundred four respondents (90.5 percent) reported performing colonoscopy as part of their clinical practice and reported an average of 41 +/- 41 colonoscopies in the last month (range, 0-635) and 457 +/- 486 in the last year (range, 2-7,000). Colonoscopy accounted for 23 +/- 16 percent of responding physicians' clinical time (range, 1-100 percent) and 27 +/- 19 percent of total charges (range, 0-100 percent). Nearly all respondents (97 percent) anticipated maintaining or increasing their volume of colonoscopy in the coming year. Eighty-four percent of respondents reported receiving some or all of their training in colonoscopy during a colon and rectal surgery fellowship. More than one-half of respondents (55 percent) believed that there should be more of an emphasis on colonoscopy on the American Board of Colon and Rectal Surgery board examination, and 81 percent believed that the annual meeting of The American Society of Colon and Rectal Surgeons should include lectures and/or courses covering colonoscopy. CONCLUSIONS: Colonoscopy plays a major role in the practices of colorectal surgeons across the world, accounting for approximately one-quarter of clinical time and total charges. Based on the expectation that this trend will continue, The American Society of Colon and Rectal Surgeons needs to aggressively support its members not only in the technical aspects of colonoscopy but also in the practice management issues.

Adult↗

PubMed2004

A prospective study of colonoscopy practice in the UK today: are we adequately prepared for national colorectal cancer screening tomorrow?

AIM: To study the availability and quality of adult and paediatric colonoscopy in three National Health Service (NHS) regions. METHOD: A prospective four month study of colonoscopies in North East Thames, West Midlands, and East Anglia. PATIENTS: Subjects undergoing colonoscopy in 68 endoscopy units. RESULTS: A total of 9223 colonoscopies were studied. The mean number of colonoscopies performed over the four month period was 142 in district general hospitals and 213 in teaching hospitals. Intravenous sedation was administered in 94.6% of procedures, but 2.2% and 11.4% of "at risk" patients did not have continuous venous access or did not receive supplemental oxygen, respectively. Caecal intubation was recorded in 76.9% of procedures but the adjusted caecal intubation rate was only 56.9%. Reasons for failing to reach the caecum included patient discomfort (34.7%), looping (29.7%), and poor bowel preparation (19.6%). A normal colonoscopy was reported in 42.1%. The most common diagnosis was polyps (22.5%) followed by diverticular disease (14.9%). Inflammatory bowel disease was recorded in 13.9% and carcinoma in 3.8%. Only half of the patients remembered being told of possible adverse events prior to the procedure. Rectal bleeding requiring admission following colonoscopy was reported in six patients. The overall perforation rate was 1:769 and colonoscopy was considered a possible factor in six deaths occurring within 30 days of the procedure. Only 17.0% of colonoscopists had received supervised training for their first 100 colonoscopies and only 39.3% had attended a training course. CONCLUSION: There is serious under provision of colonoscopy service in most NHS hospitals. Endoscopy sedation guidelines are not always adhered to and there is a wide variation in practice between units. Colonoscopy is often incomplete and does not achieve the target 90% caecal intubation rate. Serious complications of colonoscopy were comparable with previous studies. Training in colonoscopy is often inadequate and improved practice should result from better training.

Adolescent↗

PubMed1998

Colorectal neoplasm detection using virtual colonoscopy: a feasibility study.

BACKGROUND: Virtual colonoscopy is a potentially powerful tool for non-invasive colorectal evaluation. In vitro studies have established its accuracy in simulated polyp detection but little data exist regarding its use in clinical practice. AIMS: To evaluate the ability of virtual colonoscopy to detect colorectal cancers and polyps in patients with endoscopically proven colorectal neoplasms and to correlate the findings of virtual colonoscopy with those of conventional colonoscopy, surgery, and histopathology. PATIENTS: Thirty eight patients with endoscopic findings suggestive of colorectal carcinoma. METHODS: Virtual colonoscopy was performed using thin section helical computed tomography (CT) of the abdomen and pelvis after rectal insufflation of room air. Commercially available software was used to generate endoscopic "fly through" examinations of the colon from the CT data. Results were correlated with the findings of conventional colonoscopy and with the surgical and histopathological outcome in each case. RESULTS: Thirty eight pathologically proven colorectal cancers and 23 adenomatous polyps were present. On virtual colonoscopy, all cancers and all polyps measuring greater than 6 mm in size were identified; there were two false positive reports of polyps. On conventional colonoscopy, there was one false positive report of a malignant sigmoid stricture; four subcentimetre polyps were overlooked. Virtual colonoscopy enabled visualisation of the entire colon in 35 patients; conventional colonoscopy was incomplete in 14 patients. Virtual colonoscopy correctly localised all 38 cancers, compared with 32 using conventional colonoscopy. CONCLUSION: Virtual colonoscopy is a feasible method for evaluating the colon; it may have role in diagnosis of colorectal cancer and polyps.

Adult↗

PubMed1997

CT colonoscopy of colorectal neoplasms: two-dimensional and three-dimensional virtual-reality techniques with colonoscopic correlation.

OBJECTIVE: The aim of this study was to compare the diagnostic accuracy of two-dimensional (2D) CT colonography and three-dimensional (3D) virtual colonoscopy with conventional colonoscopy in patients who have suspected colorectal neoplasms. SUBJECTS AND METHODS: Twenty patients were studied (eight women and 12 men; mean age, 53 years; range, 42-85 years). All patients had findings on conventional colonoscopy suggestive of colorectal carcinoma and underwent colonic CT within 3 hr of endoscopy. Two-dimensional CT colonography and 3D virtual colonoscopy images were generated from the same data set that was obtained from thin-section helical CT of the abdomen and pelvis after rectal insufflation of room air. Three-dimensional virtual colonoscopy images were obtained by downloading CT data to a workstation equipped with commercially available software. Volume- and perspective-rendering techniques were used to achieve interactive, 3D virtual "fly-through" examinations of the colonic mucosa. The results of 2D CT colonography and 3D virtual colonoscopy were compared with the findings of conventional colonoscopy and correlated with surgical and pathologic outcome where possible. RESULTS: Twenty masses (defined as intraluminal projections 2 cm or larger in diameter) and 15 polyps (defined as projections smaller than 2 cm in diameter) were identified in our study group. All masses and 14 of 15 polyps were successfully shown on 2D colonography. Three findings of polyps on 2D colonography were false-positive, and one was false-negative. Three-dimensional virtual colonoscopy revealed 19 of 20 masses and 13 of 15 polyps. On conventional colonoscopy, all 20 masses and 13 of 15 polyps were identified, with one false-positive finding of a malignant stricture in a normal colon. Complete examination of the colon was possible in 18 of 20 patients using the 2D technique and in 17 of 20 patients using 3D virtual colonoscopy, whereas conventional colonoscopy showed the entire colon in only 12 of 20 patients. CONCLUSION: Two-dimensional CT colonography and 3D virtual colonoscopy are complementary and effective techniques for examining the colon in patients with suspected colorectal carcinoma. CT techniques offer several advantages over conventional colonoscopy including the ability to detect abnormalities proximal to obstructing carcinomas, accurate localization of abnormalities within the colon, and good patient tolerance. These CT techniques may play an important role in future diagnosis of colorectal cancer and for screening patients at risk.

Colonic Polyps↗

PubMed2004

Flat colorectal lesions in asymptomatic adults: implications for screening with CT virtual colonoscopy.

OBJECTIVE: The clinical significance of flat lesions in colorectal cancer screening remains uncertain. The purpose of this study was to investigate the frequency, histology, and virtual colonoscopy detection of flat lesions in an asymptomatic screening population. SUBJECTS AND METHODS: The morphology of all detected polyps was prospectively recorded as flat or polypoid (sessile or pedunculated) in 1,233 consecutive asymptomatic adults who underwent same-day virtual colonoscopy and optical colonoscopy. A flat morphology was defined as a shallow plaquelike broad-based lesion with a height of less than one half of its width. RESULTS: Of 344 polyps of 6 mm or greater confirmed at optical colonoscopy, 17 (4.9%) were labeled as flat at both virtual colonoscopy and optical colonoscopy; 17 (4.9%), at optical colonoscopy only; and 25 (7.3%), at virtual colonoscopy only, yielding 59 total lesions in 52 (4.2%) of 1,233 patients. Twenty-nine (49.2%) of 59 flat lesions were adenomatous, of which four measured 10 mm or greater and one 6- to 9-mm lesion was histologically advanced. None of the 148 diminutive flat lesions (< or = 5 mm) detected at optical colonoscopy was histologically advanced. Virtual colonoscopy prospectively detected 24 (82.8%) of 29 flat adenomas and 47 (80.0%) of all 59 flat lesions 6 mm or greater. In comparison, the sensitivity of virtual colonoscopy for the detection of polypoid adenomas and all polypoid lesions of 6 mm or greater was 86.2% (156/181, p = 0.58) and 81.0% (231/285, p = 0.86), respectively. CONCLUSION: Flat adenomas measuring 6 mm or greater are uncommon in a typical Western screening population, and advanced flat neoplasms are rare. The sensitivity of virtual colonoscopy for detecting flat lesions was similar to that of polypoid lesions. These results indicate that flat lesions are not a significant drawback for virtual colonoscopy screening.

Adenoma↗

PubMed1998

The appropriate use of colonoscopy in the curative management of colorectal cancer.

A total of 175 patients who underwent a curative resection for a colonic (n = 130) or a rectal cancer (n = 45) between 1986 and 1992 were entered into a routine colonoscopy program. Colonoscopies were performed 1 year after the operation, and then at 2-year intervals. The findings at colonoscopy, as well as those of preoperative colonoscopy (when performed), were recorded. Eleven anastomotic recurrences were diagnosed at an asymptomatic stage, at a mean follow-up of 14 months. All of them were identified in patients with a stage B or C primary rectosigmoid cancer. Eight patients underwent another potentially curative re-operation. Only perioperative colonoscopy (preoperative colonoscopy; first postoperative colonoscopy in patients for whom the preoperative procedure was incomplete or not performed) allowed diagnosis of second cancers (n = 7) and adenomatous polyps greater than 10 mm (n = 17). Further colonoscopies detected only polyps less than 10 mm. Positive examination rates for successive follow-up colonoscopies were 15, 20 and 23%, respectively; they were significantly higher in patients who had previously had adenomatous polyps than in patients who had not: 30% versus 6% (P < 0.025), 46% vs 5% (P < 0.005) and 38% vs 11% (P < 0.025), respectively. From these data, the following recommendations are made: (1) All colorectal cancer patients should have a total colonoscopy either before (whenever possible) or soon after operation; (2) Based on results of the perioperative colonoscopy, patients: should undergo their first follow-up colonoscopy only 3 yearly (presence of synchronous adenomatous polyps) or 5 yearly (absence of synchronous adenomatous polyps) after resection; (3) In patients with stage B or C primary rectosigmoid cancer, a surveillance of the suture line by rigid proctosigmoidoscopy should be added during the first 2 postoperative years: 6, 15 and 24 months after the operation.

Anastomosis, Surgical↗

PubMedDate not supplied

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.

Colonoscopes↗

PubMed1999

Acquisition of competence in colonoscopy: the learning curve of trainees.

BACKGROUND AND STUDY AIMS: Most official training programs in colonoscopy recommend that trainees should carry out a minimum of 100 procedures, but limited data exist on the technical progress of trainees. The aim of our study was to estimate the number of supervised procedures required for obtaining competence in colonoscopy. MATERIALS AND METHODS: Between 1990 and 1997 we have prospectively evaluated the performance of eight consecutive trainees in colonoscopy. The extent of intubated colon was recorded after each endoscopic procedure. Regression analysis was used to study the effect on the trainees' success rates on the number of colonoscopies which they had done. RESULTS: Out of 2,255 colonoscopies carried out over an 8-year period 1,408 were suitable for evaluation, fulfilling the training criteria for diagnostic colonoscopy. Senior staff (n=2) did 430 colonoscopies with a success rate of 91%, which was significantly reduced to 79% (344/434 colonoscopies; X2=20.67, df=l, P<0.001), when taking over colonoscopies which trainees had failed to complete. Regression analysis of trainees' data (y=88.97-(2185/x), r=0.74, F1,21=23.43, P<0.001) showed success rates of 67 % (95 % CI, 59 to 75 %) and 77 % (95 % CI, 66 to 88 %), when 100 and 180 procedures, respectively, had been done. These figures had been attained by the end of the second and third year of training in colonoscopy. CONCLUSIONS: Our regression analysis model shows the technical progress of trainees over a 3-year period as they learned how to carry out colonoscopy. Depending on individual skill, between 100-180 procedures, done over a 2-3-year period, are required before trainees can be considered competent in colonoscopy.

Clinical Competence↗