LAUSR

INTRODUCTION Encrustation of implanted urinary tract devices is associated with significant morbidity. Pellethane® is a polyether-based compound noted for its strength, porosity and resistance to solvents. We assessed Pellethane® thermoplastic polyurethane (TPU) with and without surface coatings 2-hydroxyethyl methacrylate (HEMA) and tetraethylene glycol dimethyl ether (TETRA) for the potential to resist encrustation in an artificial urine environment. METHODS Samples of Pellethane® TPU, HEMA Pellethane® TPU, TETRA Pellethane® TPU, and hydrogel coated ureteral stent (Cook®) were suspended in batch-flow model with an artificial urine solution (AUS). Every 48 hours for 90 days, 40% of the solution was replaced with fresh AUS. All samples were stored in a 37°C incubator. Subsequently, the samples were thoroughly dried for 48 hours before weighing. Scanning Electron Microscopy (SEM) was used to assess the degree of encrustation. Nu-Attom Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was used to determine the precise compositions of the encrustation specifically with regard to calcium, magnesium and phosphate. RESULTS At the conclusion of the 90-day trial, the samples were analyzed, and the average mass changes were as follows: stent 63.78%, uncoated Pellethane® TPU 11.50%, HEMA coated Pellethane® TPU 2.90%, and TETRA coated Pellethane® TPU 0.60%. Pellethane® TPU products, and specifically those coated with HEMA and TETRA, exhibited less average mass increase and a lesser propensity to form encrustation than the traditional urinary tract stent. The mass increases noted on coated Pellethane devices were primarily ionic, while that of the stent was not. CONCLUSION Pellethane®, particularly with a HEMA based preventative coating, may serve as a favorable alternative to traditional urinary stent material providing its improved resistance to encrustation.