A hypothesis-generating review of the water method for difficult colonoscopy

Several factors such as significant procedure-related discomfort, excessive intubation time or failed cecal intubation have been associated with difficult colonoscopy. An update of these factors and colonoscopy techniques reported to be efficacious in enhancing completion of cecal intubation in difficult colonoscopy patients is provided in this review.

A Medline search (January 2006 to July 2010) was conducted using the following search terms: colonoscopy, difficult, abdominal pain, and discomfort.

Reviewed data are tabulated for presentation. Several water-related techniques have been described separately as adjuncts to usual air insufflation to minimize discomfort, reduce intubation time and improve success rate of cecal intubation. A combination of these techniques was subjected to trial-and-error modifications followed by randomized controlled comparisons. Progressive improvement in colonoscopy outcomes that paralleled stepwise incorporation of exclusion of air insufflation, removal of residual colonic air by suction and removal of residual feces by water exchange during the insertion phase has been described.

The water method is potentially important for improving results of colonoscopy (cecal intubation) especially in unsedated patients. The unsedated option may lower costs. The success of the water method in difficult cases should be evaluated in randomized controlled trials. The call should be considered and explored by endoscopists interested in improving the quality of colonoscopy. A multicenter study to optimize the number of cases will be most desirable. In pragmatic terms, the use of the water method in difficult (unsedated) colonoscopy in the United States did receive recent editorial endorsement.