Magnetic imaging of colonoscopy: an audit of looping, accuracy and ancillary maneuvers

Overview of upcoming advances in colonoscopy

Although colonoscopy is a very commonly carried out procedure, it is not without its problems, including a risk of perforation and significant patient discomfort, especially associated with looping formation. Furthermore, looping formation may prevent a complete colonoscopy from being carried out in certain patients. The conventional colonoscope has not changed very much since its original introduction. We review promising technologies that are being promoted as a way to address the problems with current colonoscopy. There are some methods to prevent looping formation, including overtube, variable stiffness, computer-guided scopes, Aer-O-Scope, magnetic endoscopic imaging and the capsule endoscope. In recent years, with the progress of microelectromechanical and microelectronic technologies, many biomedical and robotic researchers are developing autonomous endoscopes with miniaturization of size and integration functionality that represent state of the art of the micro-robotic endoscope. The initial results by using aforementioned methods seem promising; however, there are some conflicting reports of clinical trials with the overtube colonoscope, the computer-guided scope and the variable stiffness colonoscope. There are also some limitations in the use of the Aer-o-scope and the capsule endoscope. The autonomous endoscope is based on a self-propelling property that is able to avoid looping completely. This novel technology could potentially become the next generation endoscope; however, there are still critical techniques to be approached in order to develop the effective and efficient novel endoscope.

Magnetic endoscopic imaging saves abdominal compression and patient pain in routine colonoscopies

OBJECTIVE

Magnetic endoscope imaging (MEI) is a technique for the direct visualisation of endoscope configuration within the colon. This method may prevent loop formation by giving visual feedback of endoscope movement. This study aimed to evaluate the efficacy of MEI in improving colonoscopy performance.

METHODS

Overall 1000 consecutive patients who underwent a complete routine colonoscopy were randomized into two groups: in group A with MEI, while in group B without MEI. Sedation was performed according to local standards. In both groups time to reach the cecum, the number of positioning maneuvers and involvement of a second assistant nurse were recorded. Abdominal compression was graded from 1 to 4 according to the duration and intensity of compression was quantified using a scale from 1-3 according to compression form and patient reaction.

RESULTS

Patients were randomized (group A with MEI, n = 490; group B without MEI, n = 510) and a total colonoscopy was performed. Time to cecal intubation did not differ between the groups (507 s vs 538 s; NS). The duration of abdominal compression was significantly shorter in MEI guided colonoscopy. The intensity of abdominal compression was lower in group A and fewer turn maneuvers needed per patient. A trend towards a reduced need for assistance in MEI group was seen.

CONCLUSION

Although MEI does not generally accelerate colonoscope advancement, it significantly reduces the force and the duration of abdominal compression by assistant personnel, thus minimizing patient discomfort and decreasing the need for additional staff.

Evaluation of magnetic scope navigation in screening endoscopic examination of colorectal cancer

Background

Colorectal cancer is the most common cancer in Europe. Early diagnosis and treatment gives the patient a chance for complete recovery. Screening colonoscopies in the symptom-free patients are currently performed on a wide scale. The examinations are performed under local anesthesia which does not eliminate all discomfort and pain related to the examination. The aim of this study was to evaluate magnetic scope navigation in screening endoscopic examinations performed to detect early-stage colorectal cancer.

Methods

The study group consisted of 200 patients, aged 40–65 years, who were free from colon cancer symptoms. All patients underwent complete colonoscopy under local anesthesia. The equipment could be fitted with the scope that allows three-dimensional observation of instrument localization in the bowel. The examination was performed by three experienced endoscopists, each of whom performed over 5,000 colonoscopies. The patients were randomized to two groups: those whose equipment did not have 3D navigation (group I) and those whose equipment did have 3D navigation (group II). Each group consisted of 100 cases matched by gender, age, and BMI. The authors compared the duration of introducing instrument to cecum, the pulse rate before the examination and at the time the instrument reached the cecum, and subjective pain evaluation by the patient on the visual analog scale.

Results

Group I consisted of 54 women and 46 men with a mean age of 54.6 years and mean BMI of 27.8 kg/m², and group II had 58 women and 42 men, mean age of 55.1 years and mean BMI of 26.4 kg/m². The average time it took for the instrument to reach the cecum was 216s in group I and 181s in group II (P < 0.05). Pain measured on the 10-point VAS scale was 2.44 in group I and 1.85 in group II (P < 0.05). The results showed a significantly shorter time for the instrument to reach the cecum in group II and significantly lower pain intensity during the examination was reported by the group II patients. No significant differences were found in the pulse measurements between the groups (P = 0.5).

Conclusions

3D navigation during colonoscopy decreases the time for the instrument to reach the cecum and lowers pain intensity subjectively reported by the patients. The use of 3D and the possibility to observe instrument localization and maneuvers brings more comfort to the patients.

Colonoscopy: basic principles and novel techniques

Colonoscopy is considered the 'gold standard' for detection and removal of premalignant lesions in the colon. However, studies suggest that colonoscopy is less protective for right-sided than for left-sided colorectal cancer. Optimizing the effectiveness of colonoscopy is a continuous process, and during the past decade several important quality indicators have been defined that can be used to measure the performance of colonoscopy and to identify areas for quality improvement. The quality of bowel preparation can be enhanced by split-dose regimens, which are superior to single-dose regimens. Cecal intubation rates should approximate 95% and can be optimized by good technique. In selected patients, specific devices can be used to facilitate cecal intubation. Adenoma detection rates should be monitored and exceed a minimum of 25% in men and 15% in women. To this aim, optimal withdrawal technique and adequate time for inspection are of utmost importance. Of all advanced imaging techniques, chromoendoscopy is the only technique with proven benefit for adenoma detection. Finally, the technique of polypectomy affects the number of complications as well as the success of completely removing a lesion. In this Review, we provide an overview of both standard and novel colonoscopy techniques and their impact on quality indicators.

Push enteroscopy has a 96% cecal intubation rate in colonoscopies that failed because of redundant colons

BACKGROUND

Performing a complete colonoscopy to the cecum is important for ruling out malignancy and other lesions, but failure rates are significant with a standard colonoscope. A previous study using a push enteroscope for failed colonoscopies had a completion rate of 68.7%.

OBJECTIVE

To improve the cecal intubation rate by using a newer version of a push enteroscope.

DESIGN

Retrospective study at first, then a prospective study.

SETTING

Single-center veterans health care system.

PATIENTS

A total of 47 patients in whom the cecum was not reached with a regular adult colonoscope between January 2007 and December 2010 were included. Those with poor bowel preparation were excluded.

INTERVENTIONS

Repeat colonoscopy using a new version of a push enteroscope.

MAIN OUTCOME MEASUREMENTS

The rate of cecal intubation and additional pathological findings.

RESULTS

The cecum or terminal ileum was reached in 45 patients (96%). Additional significant pathological findings in the previously unexamined colon were seen in 18 patients (38%).

LIMITATIONS

Small sample size, lack of comparison with other endoscopes.

CONCLUSIONS

Colonoscopy with a push enteroscope could be advanced to either the terminal ileum or cecum in 96% of patients, which is one of the highest known completion rates in patients in whom colonoscopy failed. Clinical management changed in all patients with additional findings.

Magnetic endoscopic imaging versus standard colonoscopy in a routine colonoscopy setting: a randomized, controlled trial

BACKGROUND

Knowing the position of the endoscope within the abdomen is important for performing a high-quality, painless colonoscopy. The recently introduced magnetic endoscopic imaging (MEI) system provides a continuous, real-time image of the endoscope during the entire procedure.

OBJECTIVE

To compare MEI versus standard colonoscopy with on-demand fluoroscopy on unsedated patients, as performed by experienced and inexperienced endoscopists.

DESIGN

Randomized, controlled trial.

SETTING

Endoscopy outpatient clinic.

PATIENTS

This study involved 810 consecutive patients (391 randomized to standard group; 419 randomized to MEI) referred for colonoscopy.

INTERVENTION

MEI or standard approach (involving on-demand fluoroscopy) during colonoscopy.

MAIN OUTCOME MEASUREMENTS

Perceived patient pain and cecal intubation rate and time to cecum.

RESULTS

For inexperienced endoscopists, the cecal intubation rate was significantly higher in the MEI group (77.8%) compared with the standard group (56.0%), P = .02 but not for experienced endoscopists (94.0% for MEI and 96.0% for standard group, P = .87). Inexperienced endoscopists had less need for assistance from a senior colleague when they used MEI (18.5%) compared with the standard technique (40.0%), P = .02. Mean (± standard deviation) time to reach the cecum was 14.0 ± 12.2 minutes in the MEI group and 15.3 ± 14.2 minutes in the standard group, P = .67.

LIMITATIONS

Single center, unblinded study.

CONCLUSION

Inexperienced endoscopists improved their colonoscopy performance when they used MEI, compared with the standard technique, but experienced endoscopists did not. The MEI may be advantageous to use for colonoscopy centers educating endoscopists. (

CLINICAL TRIAL REGISTRATION NUMBER

NCT00519129.).

Early use of magnetic endoscopic imaging by novice colonoscopists: improved performance without increase in workload

BACKGROUND

Magnetic endoscopic imaging represents a recent advance in colonoscopy training. This technique provides adjunct information to the endoscopist, specifically with regard to colonoscope loop formation.

OBJECTIVE

To examine the effect of a magnetic endoscopic imager on novice performance and workload in colonoscopy.

METHODS

Twenty complete novices received an introductory teaching session followed by the completion of two procedures on a colonoscopy model. One-half of the participants performed their first procedure with the imager, and the second procedure without, while the other one-half were trained with the inverse sequence. Two main outcome measures were recorded: distance achieved and total workload as measured by the National Aeronautics and Space Administration task load index tool.

RESULTS

A significant improvement was noted between the first and second colonoscopies, with the best performance recorded for participants who performed their first procedure with the imager, and their second without. The imager did not significantly change the total workload.&nbsp;

DISCUSSION

The study participants paid attention to the magnetic endoscopic imager; however, this did not translate into a measurable increase in novice workload. A delayed learning benefit was conferred to the group exposed to the imager on their first colonoscopy, suggesting that, even at an early training stage, the additional imager information entered working memory and was processed in a useful fashion. The introductory teaching strategy used in the present study was successful as judged by the overall distance achieved and performance improvement seen in all study participants.

Polymer Rigidity Control for Endoscopic Shaft-Guide ‘Plastolock’ — A Feasibility Study

Flexible endoscopes are used for diagnostic and therapeutic interventions in the human body for their ability to be advanced through tortuous trajectories. However, this very same property causes difficulties as well. For example, during surgery, a rigid shaft would be more beneficial since it provides more stability and it allows for better surgical accuracy. In order to keep the flexibility and to obtain the rigidity when needed, a shaft-guide with controllable rigidity could be used. In this article, we introduce the plastolock shaft-guide concept, which uses thermoplastics that are reversibly switched from rigid to compliant by changing their temperatures from 5°C to 43°C. These materials are used to make a shaft that can be rendered flexible to follow the flexible endoscope and rigid to guide it. To find polymers that are suitable for the plastolock concept, an extensive database and internet search was performed. The results suggest that many suitable materials are available or can be custom synthesized to meet the requirements. The thermoplastic polymer Purasorb® PLC 7015 was obtained and a dynamic mechanical analysis showed that it is suitable for the plastolock concept. A simple production test indicated that this material is suitable for prototyping by molding. Overall, the results in this article show that the plastolock concept can offer simple, scalable solutions for medical situations that desire stiffness at one instance and flexibility at another.

Determining scope position during colonoscopy without use of ionizing radiation or magnetic imaging: the enhanced mapping ability of the NeoGuide Endoscopy System

BACKGROUND

Knowledge of the position and shape of the endoscope could overcome many challenges of performing colonoscopy, e.g., loop formation. A novel computer-assisted colonoscope (NeoGuide Endoscopy System) delivers a real-time, three-dimensional map of the tip position and insertion tube shape in addition to the video image of the colon lumen. The aim of this study is to evaluate the mapping capabilities of the NeoGuide Endoscopy System in terms of colonic looping, insertion depth, tip position, and tip angle formation.

METHODS

Ten endoscopists with various levels of experience were each shown 70 map images generated by the NeoGuide endoscopy system in a benchtop anatomical colon model. First endoscopists were asked to determine the tip angle based on the map image and the system's corresponding tip positioning aid (20 images). In the second part they had to identify the scope-tip position in the colon model (40 images). In the third part ten images were presented for identification of colonic loops.

RESULTS

The tip angle was correctly identified in 99% (198/200) of images. Using only the map images the scope position was accurately determined in 87.5% (350/400). Identification of colonic looping of the scope was appropriate in 99% (99/100). Overall accuracy was 92.4%, and overall positive predictive value was 94.9%.

CONCLUSION

Three-dimensional map images generated by the NeoGuide endoscopy system provide accurate information regarding tip position, insertion tube position, and colonic looping.

Limited low-air insufflation is optimal for colonoscopy

BACKGROUND

Air insufflation is essential in routine colonoscopy, but obtaining optimal insufflation levels has not been discussed in the literature. The aim of this study was to determine optimal air insufflation during colonoscopic examination.

METHODS

Consecutive patients who underwent colonoscopy were randomized to receive high-air insufflation (group A, n = 83), low-air insufflation (group B, n = 84), or low-air insufflation limited to the rectum and sigmoid colon (group C, n = 83). Completion rate, cecal intubation time, propofol dose, need for abdominal compression, and turning of patients, were evaluated. The post-procedure abdominal bloating was assessed with a 0-10 visual analog scale.

RESULTS

The completion rates were similar among the three groups. The cecal intubation time was significantly shorter in group C than in group B (4.1 +/- 1.7 min vs. 5.2 +/- 3.0 min, mean +/- SD, p = 0.005). The dose of propofol was significantly less in group C than in group A (11.7 +/- 3.2 mg vs. 12.7 +/- 3.6 mg, mean +/- SD, p = 0.045). Group C needed the least manual abdominal compression (group A, B, and C: 81.9, 69, and 59%, respectively, p = 0.005) and had the least post-procedure abdominal bloating (group A, B, and C: 2.2 +/- 2.4, 2.2 +/- 2.1, and 1.5 +/- 1.9, respectively, p = 0.04).

CONCLUSIONS

We found that limited use of low-air insufflation in the rectum and sigmoid is the procedure of choice for colonoscopic examination.

Colorectal cancer incidence trends in the United States and United kingdom: evidence of right- to left-sided biological gradients with implications for screening

Several lines of evidence support the premise that screening colonoscopy reduces colorectal cancer (CRC) incidence, but there may be differential benefits for right- and left-sided tumors. To better understand the biological basis of this differential effect, we derived biomathematical models of CRC incidence trends in U.S. and U.K. populations, representing relatively high- and low-prevalence screening, respectively. Using the Surveillance Epidemiology and End Results (SEER) and the Office for National Statistics (ONS) registries (both 1973-2006), we derived stochastic multistage clonal expansion (MSCE) models for right-sided (proximal colon) and left-sided (distal colon and rectal) tumors. The MSCE concept is based on the initiation-promotion-progression paradigm of carcinogenesis and provides a quantitative description of natural tumor development from the initiation of an adenoma (via biallelic tumor suppressor gene inactivation) to the clinical detection of CRC. From 1,228,036 (SEER: 340,582; ONS: 887,454) cases, parameter estimates for models adjusted for calendar-year and birth-cohort effects showed that adenoma initiation rates were higher for right-sided tumors, whereas, paradoxically, adenoma growth rates were higher for left-sided tumors. The net effect was a higher cancer risk in the right colon only after age 70 years. Consistent with this finding, simulations of adenoma development predicted that the relative prevalence for right- versus left-sided tumors increases with increasing age, a differential effect most striking in women. Using a realistic biomathematical description of CRC development for two nationally representative registries, we show age- and sex-dependent biological gradients for right- and left-sided colorectal tumors. These findings argue for an age-, sex-, and site-directed approach to CRC screening.

Patient self-administered abdominal pressure to reduce loop formation during minimally sedated colonoscopy

CONTEXT

Assistant-administered abdominal pressure is usually required to reduce loop formation during a colonoscopy. The effect of patient self-administered abdominal pressure has not been evaluated.

OBJECTIVE

To compare the effectiveness of patient self-administered abdominal pressure with assistant-administered abdominal pressure to reduce loop formation during colonoscopy performed with minimal sedation.

PATIENTS

Consecutive patients who underwent colonoscopy were randomized to receive either patient self-administered abdominal pressure (patient group, n = 51) or assistant-administered abdominal pressure (assistant group, n = 52) when looping occurred during colonoscopy minimally sedated with meperidine. When patient-administered abdominal pressure failed to reduce the loop formation, an assistant took over and delivered the abdominal pressure.

RESULTS

No difference was found regarding cecal intubation rate, intubation time, mean pain scores, and overall satisfaction of patients between groups. However, fewer patients required assistant-administered pressure in the patient group than in the assistant group (18/51 vs. 41/52, P < 0.001).

CONCLUSIONS

Patient self-administered pressure is effective in reducing looping during minimally sedated colonoscopy.

Colon anatomy based on CT colonography and fluoroscopy: impact on looping, straightening and ancillary manoeuvres in colonoscopy

BACKGROUND

Unsedated colonoscopy is an uncomfortable procedure for most patients. Discomfort during colonoscopy is largely related to looping of the colonoscope which displaces the colon from its native configuration. Therefore, complete intubation of the colon is considerably difficult in up to 10-20% of procedures. Aims of this study were to determine the "normal" colon anatomy in CT-colonoscopy with special focus on length, number of flexures and tortuosity and to assess frequency and type of looping as well as straightening manoeuvres based on fluoroscopic findings.

METHODS

100 consecutive screening patients underwent CT colonography and another 100 cases traditional colonoscopy with fluoroscopic aid. Interactive 3D colon maps and 2D MPR images from virtual procedures were reviewed by two experienced GI-radiologists and GI-endoscopists. Colonoscopy was performed by three board-certified gastroenterologists. Fluoroscopic films of each case were recorded and retrospectively analysed.

RESULTS

There was a considerable difference in overall colonic length between CT colonography and conventional colonoscopy (167 cm vs. 93.5 cm). Number of acute angle flexures and degree of tortuosity was higher in CT colonography than previously assumed. The caecum was reached in 98/100 cases with conventional colonoscopy. Procedures were incomplete due to an obstructing sigmoid cancer and a floppy redundant colon. Looping occurred in 73/100 cases and straightening manoeuvres with fluoroscopy were highly effective in 95%. Looping was more common in older and smaller women.

CONCLUSIONS

Predictive anatomical factors for potentially difficult endoscopic colonoscopy can be defined by CT colonography. Looping occurs frequently during routine colonoscopy but hindered caecal intubation in only one case. Short-term fluoroscopy is extremely helpful to guide straightening and ancillary manoeuvres and should be used selectively in patients with looping during conventional colonoscopy.

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

Background

Safe 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.

Aim

To better understand the use and value of ETM during colonoscopy by using a device that allows real-time imaging of the colonoscope insertion shaft.

Methods

The 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.

Results

Thirty-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%).

Conclusion

The 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.

CT colonography polyp matching: differences between experienced readers

The purpose of this study was to investigate if experienced readers differ when matching polyps shown by both CT colonography (CTC) and optical colonoscopy (OC) and to explore the reasons for discrepancy. Twenty-eight CTC cases with corresponding OC were presented to eight experienced CTC readers. Cases represented a broad spectrum of findings, not completely fulfilling typical matching criteria. In 21 cases there was a single polyp on CTC and OC; in seven there were multiple polyps. Agreement between readers for matching was analyzed. For the 21 single-polyp cases, the number of correct matches per reader varied from 13 to 19. Almost complete agreement between readers was observed in 15 cases (71%), but substantial discrepancy was found for the remaining six (29%) probably due to large perceived differences in polyp size between CT and OC. Readers were able to match between 27 (71%) and 35 (92%) of the 38 CTC detected polyps in the seven cases with multiple polyps. Experienced CTC readers agree to a considerable extent when matching polyps between CTC and subsequent OC, but non-negligible disagreement exists.

Randomised controlled trial of paediatric magnetic positioning device assisted colonoscopy: a pilot and feasibility study

BACKGROUND AND AIMS

Complete colonoscopy is critical for the evaluation of many paediatric gastrointestinal diseases. The aim of the study was to investigate the feasibility of magnetic positioning device for paediatric colonoscopy and to compare completion rate and procedure time with and without the device.

METHODS

Prospective randomised controlled trial of standard colonoscopy compared to magnetic positioning device assisted colonoscopy in children and adolescents ages 7-20 years was performed.

RESULTS

Analysis showed that the proportion of successfully completed colonoscopies were 19/20 (95%) in the MP arm versus 17/18 (94.4%) in the SC arm, p=NS. The median time to complete colonoscopy to the cecum was 16.5 min (range 6-52 min) in the MP arm and 12 min (range 6-33 min) in the SC arm, p=NS.

CONCLUSIONS

Our preliminary data suggest that the use of magnetic positioning device for colonoscopy is feasible in paediatric patients. These data suggest that the use of magnetic positioning device may not be of benefit for experienced endoscopists who achieved very high colonoscopy completion rates without the MP device. Further studies are needed to determine its role in paediatric colonoscopy since this device may be of more benefit for physicians in training.

Colonoscopy: Art or science?

The focus on colorectal neoplasia has led to an exponential increase in the use of colonoscopy in many countries. Although colonoscopy facilitates the diagnosis and treatment of colonic disease, there are public health issues that include access, training, diagnostic accuracy, complications and additions to health-care costs. Because of this, colonoscopists have a responsibility to ensure that the procedure is appropriate, safe and of high-quality. This article addresses the issue of variation in technical skills that is known to exist within the endoscopic community, even among individuals with similar experience. While some of this variation reflects innate manual dexterity, another aspect is variation in the adoption of technical manoeuvers that facilitate various aspects of the procedure including rates for cecal intubation. Although technical manoeuvers are difficult to evaluate in controlled trials, there is persuasive data that high cecal intubation rates can be achieved by minimizing inflation and looping in the sigmoid colon and by the appropriate use of positional changes and abdominal pressure. In difficult settings, there is also benefit from the use of non-standard endoscopes and various accessories including overtubes.

Spatial Mental Representation: Implications for Navigation System Design

Similarities exist in how people process and represent spatial information and in the factors that contribute to disorientation, whether one is moving through airspace, on the ground, or surgically within the body. As such, design principles for presenting spatial information should bear similarities across these domains but also be somewhat specific to each. In this chapter, we review research in spatial cognition and its application to navigation system design for within-vehicle, aviation, and endoscopic navigation systems. Taken together, the research suggests three general principles for navigation system design consideration. First, multimedia displays should present spatial information visually and action and description information verbally. Second, display organizations should meet users' dynamic navigational goals. Third, navigation systems should be adaptable to users' spatial information preferences. Designers of adaptive navigation display technologies can maximize the effectiveness of those technologies by appealing to the basic spatial cognition processes employed by all users while conforming to user's domain-specific requirements.

Indications and techniques for lower intestinal endoscopy

The search for inflammatory and neoplastic lesions are the main indications for colonoscopy. A high rate of detection of polyps has become a quality criterion that depends on skilled handling of the colonoscope, on expertise and concentration during the examination, on excellent bowel preparation, and on a high standard of technical equipment. The diagnostic benefits outweigh the risk of bleeding, perforation and infection in almost all situations. Contraindications are signs of perforated intestine or imminent perforation due to deep ulcerations, necroses, or fulminant colitis. The patient's comorbidity must be considered to assess the physical stress of bowel preparation, colonoscopy and sedation. Informed consent is necessary and must be documented in all cases. It is advisable to explain planned therapeutic manoeuvres before the examination, since all non-invasive polyps must be removed completely. Total colonoscopy is possible in 95-99% of cases, but technical efforts are under way to solve the problem of looping and fixed colon angulations. Optimising optical imaging is another main focus of industrial development. The combination of narrow-band imaging, zoom magnification, and high-definition processor technology is currently the most promising tool for identifying small and flat lesions in the colon.

CT colonography: Results and limitations

Meta-analysis of data from studies of CT colonography suggests that it has excellent per-patient average sensitivity and average specificity for detection of adenomatous polyps and cancer. However, while its potential as a screening test is undoubted, there are several current limitations that will need to be overcome before it can be considered seriously by health policy makers. These revolve around issues of generalisability, which is inhibited most by a lack of trained observers and access to CT scanners, and a paucity of data relating to cost-effectiveness. Whether offering CT colonography as an alternative to competing strategies will genuinely enhance compliance also needs further and more detailed attention.

Computer-assisted colonoscopy (the NeoGuide Endoscopy System): results of the first human clinical trial ("PACE study")

OBJECTIVES

Unsedated colonoscopy is an uncomfortable procedure for most patients. Discomfort during colonoscopy is largely related to looping of the colonoscope, which displaces the colon from its native configuration and stretches attachments to the mesentery. A novel computer-assisted colonoscope utilizes a fully articulated, computer-controlled insertion tube. On manual insertion of the colonoscope, the position and angle of the scope's tip are encoded into a computer algorithm. As the colonoscope is advanced, the computer directs each successive segment to take the same shape that the tip had at a given insertion depth. The insertion tube thus changes its shape at different insertion depths in a "follow-the-leader" manner.

METHODS

This initial clinical trial with this novel colonoscopy system was designed as a prospective, nonrandomized, unblinded, feasibility study. Three physicians of varying levels of experience participated in the study.

RESULTS

Eleven consecutive patients (seven men, four women, age range 19-80) meeting inclusion criteria for screening or diagnostic colonoscopy were enrolled in the study. The cecum was reached in 10 consecutive patients (100%). Findings included diverticular disease in two cases and multiple colonic polyps in two cases. Postprocedure assessment at discharge, 48 h, and 30 days revealed no complications or adverse effects. Physician satisfaction and patient acceptance of this new technique were high.

CONCLUSIONS

In this limited, first of its kind feasibility study, the computer-assisted colonoscope was shown to perform colonoscopy safely and effectively. The colonoscope's unique design limited loop formation during colonoscopy. Large-scale clinical trials are indicated.

Guiding navigation in colonoscopy

BACKGROUND

Nonrigid environments such as the human colon present unique challenges for the navigator in maintaining spatial orientation. Conventional wisdom suggests that a navigational aid, similar to a map, that provides critical shape information would be useful. This article presents a design concept for a colonoscopy navigational aid and the results of an experiment conducted to evaluate the display for supporting navigation and spatial orientation in simulated colonoscopy.

METHODS

A navigational aid was designed to present shape information in an augmented reality display. A total of 14 untrained subjects performed a colonoscopy procedure in rigid and nonrigid colon models, with and without the navigational aid display, in a Latin square design. Performance measures such as time, distance or efficiency of travel, and location and direction error were recorded, together with subjective measures of confidence and workload.

RESULTS

The results showed that, unlike navigating in rigid environments, the subjects spent more time navigating in the nonrigid environment (p < 0.01) and traveled a longer total distance (p = 0.01). The navigational aid had no effect on performance, as compared with the no aid condition. However, subjective measures showed that the subjects were more confident about their determination of location and direction (p < 0.01). They also preferred having the aid during navigation.

CONCLUSION

A navigational aid or map that provides shape information does not seem to improve performance in colonoscopy. In fact, it may lead to a false sense of security about location and orientation in the colon. The value of a map for training purposes remains to be examined.

Rational colonoscopy, realistic simulation, and accelerated teaching

The authors hope that the combination of ScopeGuide imager (to make sense of colon looping) and the new-generation Colonoscopy Simulator (allowing structured teaching and repetitive practice) will make it possible to accelerate colonoscopy training and perhaps also will provide an acceptable way of re-honing the skills of existing endoscopists.

The aer-o-scope: proof of concept of a pneumatic, skill-independent, self-propelling, self-navigating colonoscope

BACKGROUND & AIMS

Endoscopic screening of the colon with available instruments requires considerable training, is often painful, and carries a risk of perforation. New instrument platforms for endoscopic screening could be useful. The aim of this study was to evaluate the extent of colonic intubation by using a novel self-propelled, self-navigating endoscope (the Aer-O-Scope; GI View Ltd, Ramat Gan, Israel).

METHODS

Twelve young healthy volunteers underwent complete bowel preparation followed by a nonsedated examination using the novel device. Each examination was followed by a standard colonoscopy for safety evaluation. Cecal intubation was confirmed by endoscopic landmarks and fluoroscopy.

RESULTS

In 10 out of 12 subjects (83%) the cecum was successfully reached, whereas in 2 cases the Aer-O-Scope advanced to the hepatic flexure. The time to complete advancement to cecum averaged 14.0 +/- 7 minutes, and the driving pressures averaged 34 +/- 2.3 milibar. Two subjects requested analgesics during the procedures (in both cases the cecum was reached). Four subjects experienced sweating and a bloating sensation that resolved spontaneously. All subjects were followed up to 48 hours and then for 30 days postprocedure, and no complications were observed.

CONCLUSIONS

In a preliminary pilot feasibility study of this new instrument, the Aer-O-Scope effectively intubated all or most of the colon. Further clinical studies are warranted.

CT colonography in the detection of colorectal polyps and cancer: systematic review, meta-analysis, and proposed minimum data set for study level reporting

PURPOSE

To assess the methodologic quality of available data in published reports of computed tomographic (CT) colonography by performing systematic review and meta-analysis.

MATERIALS AND METHODS

The MEDLINE database was searched for colonography reports published between 1994 and 2003, without language restriction. The terms colonography, colography, CT colonoscopy, CT pneumocolon, virtual colonoscopy, and virtual endoscopy were used. Studies were selected if the focus was detection of colorectal polyps verified with within-subject reference colonoscopy by using key methodologic criteria based on information presented at the Fourth International Symposium on Virtual Colonoscopy (Boston, Mass). Two reviewers independently abstracted methodologic characteristics. Per-patient and per-polyp detection rates were extracted, and authors were contacted, when necessary. Per-patient sensitivity and specificity were calculated for different lesion size categories, and Forest plots were produced. Meta-analysis of paired sensitivity and specificity was conducted by using a hierarchical model that enabled estimation of summary receiver operating characteristic curves allowing for variation in diagnostic threshold, and the average operating point was calculated. Per-polyp sensitivity was also calculated.

RESULTS

Of 1398 studies considered for inclusion, 24 met our criteria. There were 4181 patients with a study prevalence of abnormality of 15%-72%. Meta-analysis of 2610 patients, 206 of whom had large polyps, showed high per-patient average sensitivity (93%; 95% confidence interval [CI]: 73%, 98%) and specificity (97%; 95% CI: 95%, 99%) for colonography; sensitivity and specificity decreased to 86% (95% CI: 75%, 93%) and 86% (95% CI: 76%, 93%), respectively, when the threshold was lowered to include medium polyps. When polyps of all sizes were included, studies were too heterogeneous in sensitivity (range, 45%-97%) and specificity (range, 26%-97%) to allow meaningful meta-analysis. Of 150 cancers, 144 were detected (sensitivity, 95.9%; 95% CI: 91.4%, 98.5%). Data reporting was frequently incomplete, with no generally accepted format.

CONCLUSION

CT colonography seems sufficiently sensitive and specific in the detection of large and medium polyps; it is especially sensitive in the detection of symptomatic cancer. Studies are poorly reported, however, and the authors propose a minimum data set for study reporting.

Sedation and the technical performance of colonoscopy

The use of sedation for routine endoscopic procedures, including colonoscopy, varies widely across cultures. This variation in sedation practice is greater than any other culturally based variation in the technical performance of endoscopy. This article sequentially reviews the technical performance of colonoscopy in patients who undergo unsedated colonoscopy, sedation with narcotics and benzodiazepines, and deep sedation with propofol. For each of these approaches to colonoscopy, the advantages and disadvantages also are listed and discussed.

Aids to insertion: magnetic imaging, variable stiffness, and overtubes

Inserting the colonoscope quickly and safely without undue patient discomfort is the primary aim of the colonoscopist. The inherently mobile, flexible and unpredictable nature of the colon means that looping occurs frequently during insertion and the colonoscopist must constantly strive to keep the instrument straight whilst at the same time advancing the tip towards the caecum. Colonoscopists have struggled with insertion for many years but recent developments described in this chapter have the potential to make insertion easier and more predictable.

Advances in colonic imaging: technical improvements in colonoscopy

Colonoscopy has been available since the early 1970s and has become critical to the diagnosis and management of colorectal disorders. Features of the modern colonoscope and its variants are discussed, including the role of paediatric and variable stiffness colonoscopes for difficult insertion. The place of magnetic endoscope imaging systems and simulators in routine colonoscopy and training are examined. Finally, several recent innovations are used to illustrate how colonoscopy may evolve in the future, including new takes on the current instrument as well as potentially revolutionary pain-free, technically-easy, robotic devices for examination of the bowel.

A preliminary prospective study of the usefulness of a magnetic endoscope locating device during colonoscopy

BACKGROUND

Although magnetic endoscope imaging of the colonoscope via the Endoscope Positioning Detecting Unit (EPDU) has been studied to some extent in Europe, its application in the United States has been limited. The purposes of this study were to determine whether the technique enabled for accurate localization of the lesion and to determine if and how the device facilitated scope insertion and completion of the colonoscopic exam.

METHODS

Outpatient colonoscopies using the EPDU were performed by three experienced surgical endoscopists over a 5-month period. A specialized scope with electromagnetic coils or a regular scope with a magnetic probe insert in the instrument channel was used for the duration of the examination to identify loops and localize pathology.

RESULTS

A total of 80 colonoscopies were performed with the device. In two patients, the probe insert was removed prior to completion of the procedure; thus, the total number of examinations included in the study was 78. The EPDU was used in conjunction with transillumination to estimate the location of polyps or cancers in the 33 patients (42%) in whom such lesions were found. In the four patients who subsequently underwent operation, the lesion's location as estimated by EPDU was verified. In regard to the usefulness of the device during insertion, the EPDU led to the discovery of loops and to the application of pressure that resulted in prompt completion of the examination in 28% of cases (deemed most useful). In 33% of cases, the device identified loops and led to the application of abdominal wall pressure and early position changes, thus facilitating the examination; however it did not lead to its immediate or rapid completion. In 39% of cases, the device was not required or used for insertion due to the simple nature of the examination.

CONCLUSIONS

The EPDU was accurate in estimating lesion location. The device also holds promise as an aid in the completion of difficult exams (about 30% of cases in this study).

Determination of large bowel length and loop complexity in patients with acromegaly undergoing screening colonoscopy

BACKGROUND

Patients with acromegaly are at moderately increased risk of developing colorectal cancer and may be considered for screening colonoscopy. In turn, large bowel dimensions may be increased in these patients, factors that predict for increased risk of serious complications such as perforation.

OBJECTIVE

To evaluate this risk potential, we measured large bowel length and loop complexity using magnetic endoscopic imaging (MEI).

DESIGN

Case-control study in 25 unselected patients with acromegaly (mean age 56 years) vs. 41 nonacromegalic controls (mean age 60 years) undergoing screening colonoscopy.

MEASUREMENTS

MEI parameters were determined and age- and sex-adjusted mean differences calculated. The dependency of total large bowel length on various demographic and disease-related factors (e.g. GH exposure, IGF-I and IGFBP-3 concentrations) was assessed using regression techniques.

RESULTS

Total large bowel length was increased by 20%[95% confidence interval (CI) 9-31%] in patients with acromegaly compared with controls (unadjusted and adjusted; P-values < 0.001). Acromegaly was also associated with increased time taken to reach the caecum (P = 0.01) and increased pelvic loop complexities (5/25 vs. 1/41, Fisher's exact test: P = 0.03). Total large bowel length was predicted by age at colonoscopy (P = 0.003) and patient height (P = 0.03), but not by surrogate biochemical markers of disease activity.

CONCLUSIONS

Acromegaly is associated with increased large bowel length and loop complexity making colonoscopy technically challenging, and theoretically increasing the risk of serious complications. Patients need to be counselled accordingly, and appropriate resources with experienced staff allocated.

Computed tomographic colonography without cathartic preparation for the detection of colorectal polyps

BACKGROUND AND AIMS

We prospectively compared the performance of low-dose multidetector computed tomographic colonography (CTC) without cathartic preparation with that of colonoscopy for the detection of colorectal polyps.

METHODS

A total of 203 patients underwent low-dose CTC without cathartic preparation followed by colonoscopy. Before CTC, fecal tagging was achieved by adding diatrizoate meglumine and diatrizoate sodium to regular meals. No subtraction of tagged feces was performed. Colonoscopy was performed 3-7 days after CTC. Three readers interpreted the CTC examinations separately and independently using a primary 2-dimensional approach using multiplanar reconstructions and 3-dimensional images for further characterization. Colonoscopy with segmental unblinding was used as reference standard. The sensitivity of CTC was calculated both on a per-polyp and a per-patient basis. For the latter, specificity, positive predictive values, and negative predictive values were also calculated.

RESULTS

CTC had an average sensitivity of 95.5% (95% confidence interval [CI], 92.1%-99%) for the identification of colorectal polyps > or =8 mm. With regard to per-patient analysis, CTC yielded an average sensitivity of 89.9% (95% CI, 86%-93.7%), an average specificity of 92.2% (95% CI, 89.5%-94.9%), an average positive predictive value of 88% (95% CI, 83.3%-91.5%), and an average negative predictive value of 93.5% (95% CI, 90.9%-96%). Interobserver agreement was high on a per-polyp basis (kappa statistic range, .61-.74) and high to excellent on a per-patient basis (kappa statistic range, .79-.91).

CONCLUSIONS

Low-dose multidetector CTC without cathartic preparation compares favorably with colonoscopy for the detection of colorectal polyps.

Does fluoroscopic imaging still have a role in colonoscopy?

GOAL

To assess the use and value of fluoroscopic imaging in difficult colonoscopy.

BACKGROUND

Few endoscopy centers have easy access to fluoroscopy to facilitate difficult colonoscopy. Its benefits are therefore unclear. Although interest in colonoscope imaging has recently been stimulated by magnetic imaging techniques, these are expensive and unlikely to be widely available for some time.

STUDY

During routine colonoscopy lists, a mobile fluoroscopy unit was used when colonoscopy could not be completed in the absence of stricturing despite changes in patient position and application of external pressure. This retrospective review assesses the percentage of procedures completed with and without fluoroscopy.

RESULTS

A series of 1551 procedures in adult patients without colon resection and with satisfactory bowel preparation was analyzed. The cecal intubation rate was 95.1% (1475/1551), rising to 96.5% (1475/1528) when impassable strictures were excluded. Fluoroscopy was used in 61 (4%) of the 1528 procedures without stricture, but allowed completion in only 13% (8/61). In the absence of stricture, fluoroscopy improved completion rate by only 0.5% (from 96.0% to 96.5%).

CONCLUSIONS

Fluoroscopy is seldom required and even then contributes little to success. Magnetic imaging, which provides continuous 3-dimensional images, may be more likely to speed and facilitate completion.

A novel shape-locking guide for prevention of sigmoid looping during colonoscopy

BACKGROUND

Looping of the endoscope in the sigmoid colon and other colonic segments often represents a significant challenge to the performance of comfortable, complete, and swift colonoscopy. This report describes the design and operation of a new device that addresses this problem, together with preliminary preclinical experience with this use of this shape-locking guide (SG-1).

METHODS

The shape-locking guide is an overtube that can be converted from a flexible to a rigid configuration on demand. When in the rigid configuration, the shape-locking guide is designed to protect the colon wall from lateral forces exerted by the colonoscope. The shape-locking guide was evaluated in vitro by using an artificial colon model to learn how to operate it, and to assess feasibility for prevention of colon looping. In addition, safety was assessed in vivo in a pig model.

RESULTS

In vitro, the shape-locking guide prevented colonic looping and, thereby, aided completion of "colonoscopy" in the artificial colon model. Subsequent in vivo studies demonstrated that use of the shape-locking guide is safe and feasible; it performed well with respect to ease of insertion and avoidance of sigmoid looping. There was no evidence of significant injury to the colon or adjacent abdominal viscera.

CONCLUSIONS

This preliminary study shows that use of the shape-locking guide is safe and that it has performance characteristics that may assist the performance of colonoscopy. Human trials are being undertaken.

Perforation during colonoscopy in endoscopic ambulatory surgical centers

BACKGROUND

Perforation as a complication of colonoscopy is estimated to occur in 0.01% to 0.3% of procedures, but the frequency in ambulatory settings is unknown. This study determined the number of perforations occurring within a network of endoscopic ambulatory surgery centers.

METHODS

A total of 116,000 colonoscopies were performed within one network of 45 endoscopic ambulatory surgery centers in the United States during 1999. All identified perforations were reported to the network clinical director and reviewed by a panel of 3 gastroenterologists.

RESULTS

There were 37 (0.03%) perforations; 27 in women and 10 in men. Median patient age was 75 years (range 39-87 years); 18 patients (49%) had diverticular disease and 20 (54%) had a history of pelvic or colonic surgery. Twenty-four (65%) procedures were diagnostic, and 13 (35%) were therapeutic. The most common site of perforation was the sigmoid colon (62%); followed by the ascending colon (16%); cecum, transverse colon, and splenic flexure (11%); and rectum, anastomotic, or unknown (11%). The time to diagnosis ranged from immediate to 72 hours (29 <1 hour, 8 >1 hour). All patients were hospitalized; 35 (95%) underwent exploratory laparotomy, and 2 (5%) were treated conservatively. No patient died.

CONCLUSIONS

Reported perforations for procedures performed in endoscopic ambulatory surgery centers occurred most frequently during diagnostic colonoscopy in older woman with a history of surgery or diverticular disease. Reported perforations in endoscopic ambulatory surgery centers were uncommon.

Validation of virtual colonoscopy in the detection of colorectal polyps and masses: rationale for proper study design

BACKGROUND

Colorectal cancer, the second-leading cause of cancer-related mortality, is a preventable malignancy in many cases. Despite the availability of several screening modalities, compliance with screening recommendations remains unacceptably low. Virtual colonoscopy is a novel, minimally-invasive technique with the potential to increase colorectal cancer screening rates, but its effectiveness must first be validated. Published studies comparing virtual colonoscopy to conventional colonoscopy have reported varying results. These discrepancies may be attributed to differences in bowel preparation and scanning techniques, as well as errors in endoscopic lesion measurement, endoscopic colonic segmental localization, and the ability of conventional colonoscopy to actually detect lesions. These methodological issues can affect scientific results and ultimately affect the public's perception of this emerging technique.

AIM

The goal of this report is to expose existing methodological shortcomings and propose solutions incorporated in this study design. This article describes the rationale, study design, and outcome definitions of a single-center, blinded, direct comparative trial aiming at assessing the ability of virtual colonoscopy to detect colorectal polyps and masses relative to the criterion standard, conventional colonoscopy. DESIGN FEATURES: Bowel preparation was standardized using oral sodium phosphate lavage, orally administered iodinated contrast, and controlled colonic insufflation. Segmental unblinding allowed a second-look when results were discrepant and polyp matching was performed using an algorithm based on segmental localization and lesion size determination.

CONCLUSIONS

This methodology could be applied to other studies assessing the accuracy of virtual colonoscopy in order to have uniformity of results.

The role of sigmoidoscopy and colonoscopy in the diagnosis and management of lower gastrointestinal disorders: technique, indications, and contraindications

Flexible sigmoidoscopy and colonoscopy have revolutionized the clinical management of colonic diseases. Colonoscopy has a broad range of indications, including evaluating lower GI symptoms such as lower GI bleeding, evaluating abnormal radiographic findings, and screening and surveillance for colon cancer. Colonoscopy is increasingly being used therapeutically. Patient evaluation, patient instructions, and colonic preparation before colonoscopy are essential for safe and efficient colonoscopy. Intravenous sedation reduces patient pain and anxiety during colonoscopy, but requires monitoring by pulse oximetry and automated measurements of vital signs. An experienced colonoscopist can complete colonoscopy in 90% or more of cases, using maneuvers to maintain the colonic lumen in view, straighten the colonoscope, and avoid looping during colonic intubation.

Cutaneous metastases from a gastrointestinal stromal tumor of the stomach: review of literature

Gastrointestinal stromal tumors (GIST) are neoplasms of mesenchymal origin which may or may not be malignant. Malignant GIST rarely metastasize to distal organs. A case of cutaneous metastasis from GIST has been presented. This case is particularly interesting because not only did the patient have multiple metastases from GIST, but eventually developed cutaneous metastasis. This phenomenon has not been reported in the literature. The most current literature on gastrointestinal stromal tumors has been reviewed.

Use of video and magnetic endoscope imaging for rating competence at colonoscopy: validation of a measurement tool

BACKGROUND

Counting the number of procedures performed provides at best a crude measure of technical competence in colonoscopy. The aim of this study was to develop and validate a qualitative and a quantitative score for measuring technical competency in colonoscopy using videotape evaluation.

METHODS

Eighteen endoscopists with varying levels of experience were prospectively videotaped during colonoscope insertion. The following were recorded simultaneously: a closed circuit television view showing instrument handling, the endoscopic luminal view, and a continuous display of the colonoscope configuration (magnetic endoscope imaging). Videotapes were reviewed blindly and in random order by 3 experts. Performance in 3 categories was evaluated: (1) manipulation of instrument controls (0-10), (2) manipulation of the insertion tube (0-6) and (3) depth of insertion (0-4). A global assessment of competence was given for each endoscopist.

RESULTS

Comparing the total scores as assessed by the 3 blinded experts, for each individual endoscopist, there were significant differences. However, there was good interobserver agreement and correlation between the individual scores and global assessment ratings of competence (p < 0.0001).

CONCLUSIONS

The video assessment tool described appears to measure technical competence at colonoscopy, although in its present form it lacks reliability. Refinement of the score may improve reliability and deserves further evaluation.

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.

Effect of magnetic endoscope imaging on patient tolerance and sedation requirements during colonoscopy: a randomized controlled trial

BACKGROUND

Pain during colonoscopy is primarily related to mesenteric stretching from looping of the colonoscope insertion tube. Prompt recognition and removal of loops reduces patient discomfort and may lessen sedation requirements. Magnetic endoscope imaging allows real-time visualization of the colonoscope during insertion. The effect of magnetic endoscope imaging on patient pain and sedation requirements was assessed in a prospective randomized controlled trial.

METHODS

A total of 122 consecutive patients undergoing routine colonoscopy by a single experienced endoscopist were randomized to have the procedure performed either with the endoscopist viewing the imager display (n = 62), or without the imager view (n = 60). Procedures began with administration of hyoscine-N-butylbromide alone, and sedative medications (midazolam and meperidine) were self-administered by the patient with a patient-controlled analgesia pump. Cardiorespiratory parameters were recorded and patient pain was assessed with a 100-mm visual analogue scale.

RESULTS

The number of attempts at straightening the colonoscope was fewer (median 8 [0-66] vs. 15 [0-87], p = 0.0076) and the duration of looping less (median 4.5 min [0-27.3 min] vs. 6.4 min [0-29.4 min]), when the endoscopist was able to see the imager view. The total number of patient demands (by patient-controlled analgesia) for medication (median 1 vs. 2.5) and total doses of midazolam (median 0.44 mg vs. 0.88 mg) and meperidine (median 16.75 mg vs. 32.5 mg) administered did not significantly differ between patients examined with or without the imager. Patient pain scores were also similar.

CONCLUSIONS

Magnetic endoscope imaging allows accurate assessment and straightening of loops during colonoscopy, but without a significant reduction in patient requirements for sedative medication or improvement in patient tolerance. However, the dosages of sedation drugs used were small.

The impact of new technology on surgery for colorectal cancer

Advances in technology continue at a rapid pace and affect all aspects of life, including surgery. We have reviewed some of these advances and the impact they are having on the investigation and management of colorectal cancer. Modern endoscopes, with magnifying, variable stiffness and localisation capabilities are making the primary investigation of colonic cancer easier and more acceptable for patients. Imaging investigations looking at primary, metastatic and recurrent disease are shifting to digital data sets, which can be stored, reviewed remotely, potentially fused with other modalities and reconstructed as 3 dimensional (3D) images for the purposes of advanced diagnostic interpretation and computer assisted surgery. They include virtual colonoscopy, trans-rectal ultrasound, magnetic resonance imaging, positron emission tomography and radioimmunoscintigraphy. Once a colorectal carcinoma is diagnosed, the treatment options available are expanding. Colonic stents are being used to relieve large bowel obstruction, either as a palliative measure or to improve the patient’s overall condition before definitive surgery. Transanal endoscopic microsurgery and minimally invasive techniques are being used with similar outcomes and a lower mortality, morbidity and hospital stay than open trans-abdominal surgery. Transanal endoscopic microsurgery allows precise excision of both benign and early malignant lesions in the mid and upper rectum. Survival of patients with inoperable hepatic metastases following radiofrequency ablation is encouraging. Robotics and telemedicine are taking surgery well into the 21^st century. Artificial neural networks are being developed to enable us to predict the outcome for individual patients. New technology has a major impact on the way we practice surgery for colorectal cancer.