Evaluation of the Biodurability of Polyurethane-Covered Stent Using a Flow Phantom.
10.3348/kjr.2001.2.2.75
- Author:
Dong Hyun KIM
;
Sung Gwon KANG
;
Jung Ryul CHOI
;
Ju Nam BYUN
;
Young Chul KIM
;
Young Moo AHN
- Publication Type:Original Article ; Evaluation Studies ; Research Support, Non-U.S. Gov't
- Keywords:
Biliary stent;
Biodegradation;
Polyurethane membrane
- MeSH:
Bile Acids and Salts/physiology;
Biodegradation;
Hydrogen-Ion Concentration;
Microscopy, Electron, Scanning/*instrumentation;
Phantoms, Imaging;
*Polyurethanes;
*Stents;
Support, Non-U.S. Gov't;
Tensile Strength;
Time Factors
- From:Korean Journal of Radiology
2001;2(2):75-79
- CountryRepublic of Korea
- Language:English
-
Abstract:
OBJECTIVE:To evaluate the biodurability of the covering material in retrievable metallic stents covered with polycarbonate polyurethane. MATERIALS AND METHODS: Using a peristaltic pump at a constant rate of 1ml/min, bile was recirculated from a reservoir through a long tube containing four stents. Each of these was removed from the system every two weeks and a radial tensile strength test and scanning electron microscopy (SEM) were performed. Each stent, removed at 2, 4, 6 and 8 weeks, was compared with a control stent not exposed to bile juice. RESULTS: Gross examination showed that stents were intact at 2 weeks, but at 4, 6 and 8 weeks cracks were observed. The size of these increased gradually in accordance with the duration of exposure, and at 8 weeks several large holes in the polyurethane membrane were evident. With regard to radial tensile strength, extension and peak load at break were 84.47% and 10.030 N/mm, 54.90% and 6.769 N/mm, 16.55% and 2.452 N/mm, 11.21% and 1.373 N/mm at 0, 2, 4 and 6 weeks, respectively. Scanning electron microscopy at 2 weeks revealed intermittent pitting and cracking, and examination at 4, 6 and 8 weeks showed that the size of these defects was gradually increasing. CONCLUSION: When the polyurethane membrane was exposed to bile, biodegradation was first observed at week two and increased gradually according to the duration of exposure.
