AUA 2017: Polyurethanes for Urinary Stents: A Study on Materials’ Stone Encrustation Performances

Boston, MA ( Encrustation has been a serious issue regarding materials used to build indwelling stents and catheters for urologic use. Currently there are multiple medically available material options for stents and catheters, which include: polycarbonate polyurethane (PU), silicone, polyether PU, and polyester PU. The goal of Li and colleges was to determine the levels of encrustation of each material against the ‘gold standard’ silicon.

Li and colleagues designed and built an in vitro continuous flow model to test the incrustation. Artificial urine formulated by Tunney et al was chosen. Experiments were run for a 5-day period with daily urine refresh. Each material was run twice to ensure stability of results and calcium encrustation was measured via o-Cresolphalein method.

After the 10-day series of each material Li et al ran Fisher’s exact tests and ANOVA were performed to determine statistical differences. The study team found that polyether has a consistently lower rate of encrustation, maintaining linear growth for a max of ~11 mg/mm2. Polyester and Aromatic polyester were also found to have a significantly lower rate of encrustation maxing out at ~15 mg/mm2 each.

Li suggests the use of polyester and aromatic polyester could be beneficial to flow dynamics for patients receiving indwelling stents and/or catheters. He also explains that the study team was able to develop a reliable assay for stone encrustation evaluation. Li also concluded that the use of silicone as the standard should be further investigated considering their results.

Presented By: Gary Li, Tufts University Cambridge, Massachusetts, USA

Author(s): Gary Li, Jun Li, Zheng Zhang, Morgan Tierney, Cambridge, MA

Affiliation: Tufts University Cambridge, Massachusetts

Written By: Anthony Warner, a research intern from the University of California, Irvine, on behalf of

at the 2017 AUA Annual Meeting - May 12 - 16, 2017 – Boston, Massachusetts, USA