Several new instruments have been developed in the effort to improve the acceptance of colonoscopy for colorectal cancer screening. A new colonoscope, the Invendoscope, is presented here. It consists of an endoscopic sheath with an inverted sleeve, instrument channel, and an electrohydraulic deflecting tip. The instrument is steered by a hand-held device and propelled by a motorized drive unit.

Our purpose was to evaluate the feasibility of the new Invendoscope SC40.

Prospective single-arm pilot study over 2 time periods using 2 different instrument prototypes (170 and 180/200 cm).

Thirty-four healthy volunteers (19 men, mean age 49.7 years). Technical instrument defects led to premature termination in 5 additional volunteers during the 2 study periods (4 in phase 1, 1 in phase 2), who were excluded from further analysis.

Total colonoscopy was attempted, with all procedures being performed without sedation.

Cecal intubation rate.

The cecum was reached in 82% of the 34 cases (95% CI, 66%-92%), with better results in period 2 than in period 1 (90% vs 79%); of the 6 incomplete examinations, 4 reached the mid transverse colon or beyond and 2 were stopped in the sigmoid colon because of pain. The volunteer rating showed a mean score of 1.96 (range 1-6; 1 = no discomfort). No complications were encountered.

No data regarding diagnostic accuracy and no data comparing the instrument with conventional colonoscopy are available as yet.

This pilot proof-of-principle study of a new motor-driven colonoscope showed promising cecal intubation rates and an absence of pain in 92% of cases. Further clinical and comparative studies are warranted.