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.