Feasibility of the transparent cap-fitted colonoscope for screening and mucosal resection

A transparent plastic cap of 17 mm in outer diameter, 15 mm in inner diameter, and 10 mm in length can be easily attached to the tip of a colonoscope. By using the cap, a better view of the lesions hiding at the opposite side of the fold can be obtained. When a flat colonic lesion is found, a submucosal injection of saline solution is performed, the target mucosa is sucked inside the cap, snared under a full endoscopic suction, and resected by an electrical current. This procedure is called endoscopic mucosal resection using transparent cap-fitted endoscope (EMRC). Feasibility of the cap-fitted colonoscope for screening colonoscopic examination and mucosal resection was evaluated.

One hundred forty patients were randomly allocated for screening with a normal colonoscope (NCF) or that with the cap-fitted colonoscope (CCF). Average time for insertion up to the cecum, patients' discomfort during insertion expressed in 4 degrees, and average number of lesions found in one patient were compared. Thirty lesions randomly allocated for mucosal resection with conventional strip biopsy or EMRC were also evaluated.

Time consumed for insertion up to the cecum with the CCF (12.4 +/- 6.6 minutes) was the same as that with the NCF (12.3 +/- 5.2 minutes), and there was no significant difference in patients' discomfort; however, the average number of lesions found in one patient was larger when using the CCF (0.86 +/- 0.96) than when using the NCF (0.58 +/- 0.81). For mucosal resection, 40 flat or wide-based lesions including 6 mucosal carcinomas were resected with EMRC. We experienced only one pinhole perforation of the ascending colon by heat damage, which was treated successfully by surgery. There was no other major complication or recurrence.

The cap-fitted endoscope was equal in maneuverability, was excellent in sensitivity in comparison with the regular colonoscope, and was thought to be feasible both in screening and mucosal resection.