Magnetic endoscopic imaging as a guide to smart colonoscopy

Abstract

The enormous numbers of colonoscopies now performed worldwide make it more important than ever to optimize initial colonoscopy training and to develop a methodology for assessing the objective competence of endoscopists. At the early training stage only completion rate and the time taken to reach the cecum are the available end-points, which provide realistic but clear measures of actual skill, while perforation and potential mortality are cited as significant limitations of colonoscopy. Therefore, in the early days of colonoscopy the procedure was often performed with the use of fluoroscopy to visualize the endoscope.1 Today, fluoroscopy is reserved for exceptional cases due to the added expense, inconvenience and radiation risk it presents, both to the patient and the medical staff. As a consequence generations of endoscopists have remained unaware of the potential advantages that imaging of the endoscope configuration offers when compared to the blind insertion of the endoscope. Loop recognition, management and straightening are all important aspects of quality colonoscopy. Loops are easier to understand and reduced when displayed on a screen, rather than by guessing and by feel alone. While it is a bonus for trainees and certainly for the patient to have the teacher standing alongside, a long apprenticeship phase and the 100–300 subsequent solo procedures needed to achieve supposed competence are also costly for the hospital and the supervising endoscopist (C. Williams 2011, pers. comm.). In 1993 magnetic endoscope imaging (MEI) was first presented as an alternative to fluoroscopy.2 MEI is derived from very low-strength magnetic fields generated by a series of tiny wire coils positioned along the length of the colonoscope. It provides real-time three-dimensional views of the colonoscope shaft configuration and its location within the abdomen on a separate computer monitor. Several studies have shown that MEI reliably permits the exact localization of colonic pathologies.3-5 Thus, it can be used for follow-up examination after local treatment or in patients with small colorectal tumors for whom surgery is planned. Although initial studies suggested that the use of the MEI could also improve the performance of both skilled and trainee endoscopists allowing a higher colonoscopy completion rate,6 only a few further randomized trials have been reported in the literature and showed conflicting results with regard to intubation times and rates as well as the need for sedatives and the pain experienced by the patient.3, 7-9 Moreover, most of these studies did not include enough patients to gain enough statistical power to show the difference between the groups who do and do not use MEI. In this issue of the Journal of Digestive Diseases Dechêne et al. present the largest study evaluating the use of MEI for colonoscopy done to date and add valuable information about the utility of MEI.10 With the inclusion of 1000 patients results are reliable. The authors found that the use of MEI did not accelerate cecal intubation times. However, the duration of abdominal compression was significantly shorter and the intensity of abdominal compression was lower in MEI-guided colonoscopy. Moreover, fewer turn maneuvers per patient were needed in the group with MEI. This depicts what MEI is able to offer for colonoscopy in the era of potent analgosedation. MEI facilitates the technical performance of colonoscopy by showing what is really going on inside the patient. Endoscope looping and the effects of rotation and withdrawal can be directly observed. Further, MEI permits the precise and effective administration of external abdominal compression. On the other hand, cecal intubation rates and times are rather dependent on adequate bowel preparation and the use of sedatives allowing the insertion of the endoscope even in the presence of normally painful stretching of the colon.11 Nevertheless, the personal aim of each endoscopist should be the exertion of the optimal technique, for example, by the use of MEI, thereby keeping the use of sedatives low. Given the obvious advantages of the application of a safe endoscope imaging method the question arises why MEI has not been used in every endoscopy unit so far. Indeed, most endoscopists consider that the benefits of MEI are not big enough to compensate for the additional costs for the special equipment and colonoscopes. Here, the manufacturer would have to concede. For the endoscopist MEI is finally like all the other small things that make life easier: once you have used it, you would not like to not to have it.