Cap-Assisted Colonoscopy (CAC) Significantly Extends Visualization in the Right Colon

Zusammenfassung

Hintergrund: Obgleich die Koloskopie als Standarduntersuchung bei der Diagnose für Neoplasien im Kolon etabliert ist, wird eine große Zahl von klinisch relevanten Schleimhautveränderungen sogar von erfahrenen Endoskopikern übersehen. Besondere Probleme bestehen hierbei durch schlecht einsehbare Areale hinter den Schleimhautfalten und im rechten Kolon. Dieses Problem wird durch die zunehmende Zahl von Publikationen, in denen Intervallkarzinome beschrieben werden, reflektiert. Eine transparente Aufsetzkappe, die auf die Spitze des Koloskops montiert wird, könnte ein einfaches Verfahren darstellen, den endoskopisch einsehbaren Bereich zu vergrößern und somit die Detektionsrate von Schleimhautveränderungen zu verbessern. Die Daten in der Literatur sind diesbez. aber widersprüchlich. Material und Methode: Die Signifikanz einer Kappen-assistierten Koloskopie (CAC) bez. der endoskopisch einsehbaren Oberfläche in verschiedenen Kolonsegmenten (Rektum, Sigma, Colon descendens, Colon transversum, Colon ascendens, Caecum) wurde in randomisierten „Back-to-back“-Koloskopien mit und ohne Aufsetzkappe quantitativ untersucht. Die Untersuchungen wurden von 5 unabhängigen Untersuchern in einem Koloskopie-Trainingsmodell durchgeführt. Die innere Oberfläche des artifiziellen Kolons wurde mit einem Punkteraster versehen, wobei das Verhältnis der visualisierten Punkte zur tatsächlichen Anzahl als Maß für die einsehbare Fläche in den Kolonsegmenten diente. Ergebnisse: Die Gesamt- und Vorschubzeit in die verschiedenen Kolonsegmente waren zwischen den Koloskopien mit und ohne Kappe nicht signifikant unterschiedlich. Im Gegensatz hierzu war die Gesamtrückzugszeit und die Rückzugszeit mit Kappe aus dem Caecum, Colon ascendens, Colon descendens und Rektum signifikant verlängert, nicht aber für das Colon transversum und Sigma. Die einsehbare Oberfläche war mit Kappe signifikant vergrößert. Insgesamt wurden ohne Kappe 59,76 ± 2,70 % der maximal möglichen Punkte visualisiert und mit Kappe 85,36 ± 9,62 %. Die Verbesserung der Visualisierung war nur für das rechtsseitige Kolon, aber nicht für das Rektum, Sigma oder Colon descendens signifikant. Schlussfolgerung: Die Ergebnisse der Studie lassen vermuten, dass die Vergrößerung der endoskopisch einsehbaren Schleimhautfläche durch eine transparente Kappe insbesondere für das rechtsseitige Kolon relevant ist.

Abstract

Background: Although colonoscopy is the standard procedure in the diagnosis of colorectal neoplasia, a significant number of clinically relevant lesions may be missed even by experienced endoscopists using current technology. Particular problems may occur with blind spots behind the semilunar folds and within the right colon. A transparent cap mounted at the tip of a colonoscope may be an easy way to extend the visual field during colonoscopy and may improve the detection rate of mucosal lesions. However, data in the literature are controversial and the quantity of the potential extension of visualization by a transparent cap has not been reported yet. Material and Methods: The significance of cap-assisted colonoscopy (CAC) to increase visualization within different colonic segments (rectum, sigmoid colon, descending colon, transverse colon, ascending colon, cecum) was quantitatively analyzed by randomized back-to-back colonoscopies with and without cap. The investigations were performed in a colonic training model by 5 investigators. The inner colonic surface was stained by a raster of dots and the number of dots counted during colonoscopy served as a measure for the visible surface area of each segment. Results: The time to advance the colonoscope to the respective colonic segments and the overall time to reach the cecum were not significantly different between conventional and CAC. In contrast, overall withdrawal time and withdrawal times for the cecum, ascending colon, descending colon and rectum were significantly longer for CAC, but not for the transverse and sigmoid colon. Visualization of the colonic surface was significantly increased during CAC. Overall, 59.76 ± 2.70 % of the maximal countable dots were visualized without cap and 85.36 ± 9.62 % with cap. The improvement of visualization was only significant for the right colon, but not for the rectum, sigmoid or descending colon. Conclusion: The finding of the present study suggests that the extension of visualization by CAC may be of particular value for the right colon.

Schlüsselwörter

Kappen-assistierte Koloskopie - Polypendetektionsrate - Visualisierung - Intervallkarzinome

Key words

cap-assisted colonoscopy - polyp detection - visual field - interval carcinoma

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