ASSESSMENT OF URINARY-TRACT BIOMATERIAL ENCRUSTATION USING A MODIFIEDROBBINS DEVICE CONTINUOUS-FLOW MODEL

Encrustation of biomaterials employed in the urinary tract remains a m ajor problem resulting in obstruction or blockage of catheters and ste nts. Therefore, resistance to encrustation is a desirable feature of b iomaterials employed in such devices, The novel assessment of biomater ial encrustation employing a continuous flow model based on a modified Robbins device is described, Artificial urine was used in conjunction with 5% CO2 to simulate the physiological environment within the uppe r urinary tract, The widely used urinary device biomaterials, silicone and polyurethane, were investigated in the model for hydroxyapatite a nd struvite encrustation, Scanning electron microscopy, energy dispers ive X-ray analysis, and atomic absorption spectroscopy all showed that silicone was less prone to encrustation than polyurethane and that hy droxyapatite deposition was predominant on both surfaces, The model ha s the advantage that a large number of biomaterials may be investigate d simultaneously because several Robbins devices may be placed in para llel, The model is recommended for comparative evaluation of biomateri al candidates for use in urinary tract devices. (C) 1997 John Wiley & Sons, Inc.