New approach to radial expansive force measurement of self expandable esophageal metal stents

The accurate measurement of radial expansive force is crucial for optimal d esign and implantation of self expandable esophageal metal stents. In the p resent study, a new method of measurement under experimental conditions sim ulating actual stent implantation has been developed. This method offers pr ecise and reproducible measurements and can be applied to a wide variety of stent types. In particular, the method enables one to measure expansive pr essure as well as the true radial expansive force up to the radial compress ion ratio of 72%, covering the range of compression often encountered in a partially obstructed lumen. The test results for various kinds of metal ste nts are presented and compared. Based on these results, three important poi nts of observation critical in explaining and predicting the expansion char acteristics of stents have been reported. Further understanding and charact erization of these findings will be necessary for developing new stents wit h outstanding clinical efficacy.