Fabrication and mechanical testing of polydioxanone hook cross biodegradable self-expandable enteric stent: impact of fabrication density and mechanical properties of the stent.

Background: The mechanical properties of biodegradable stent when fabricated using different number of pins per row of fabrication has been limited. We compared the radial compressive force of polydioxanone (PDO) stent that was fabricated in hook and cross manner, using 13, 17 and 19 pins per row and measure the radial compressive force and ex vivo deployment.

Methods: The PDO stents fabricated by the in-house aluminum mandrel were tested for radial force using plate compression until the stent achieved 50% strain. The relationship between compression force and %strain was calculated. Ex vivo testing of stent expansion against short segment stricture was performed in a pig small intestine compared between PDO hook cross PDO stent and braided metallic stent.

Results: The stent shortening of 16.40%, 31.20% and 19.24% was observed in 13-, 17- and 19-pin-per-row, respectively. The maximum force to achieve 50% strain were 0.503, 1.168 and 1.008 N for 13, 17 and 19 pins per row, respectively. The stent fabricated using hook and cross pattern demonstrated higher conformability to anatomical stricture when compared with braided stent.

Conclusions: PDO stent fabricated using 17 pins per row demonstrated highest radial force when compared with 13 and 19 pins per row.