Grant: Collaborative Health Research Projects (NSERC partnered)

At least 10% of the Canadian population (>3.5 million Canadians) will develop a kidney stone in their life, resulting in significant patient morbidity and burden on the healthcare system. This problem is further deteriorated as ~50% of the patients will have a repeat episode within 5 years. Most patients are treated by placing a ureteral stent, a thin hollow plastic tube, in the ureter (the duct that bridges the kidney to the bladder) to ensure proper urine drainage past the stone that may be blocking it. Ureteral stents are also used in cancer patients to maintain urine flow through the ureter that may be compressed by growing tumor. The stent itself, however, often causes an obstruction in the urine flow, by limiting the ureter's wave-like motion to push urine down to the bladder and/or by building up crystals on the stent. In such case, the kidney swells, a condition known as hydronephrosis, which results in kidney injury and eventual failure if left untreated. This research will develop a novel "smart" ureteral stent that will continuously track renal pressure while it is indwelling, uniquely allowing for early detection of increased pressure before damaging hydronephrosis develops. This will enable non-invasive, quantitative, and cost-effective tracking that is currently not available via any existing diagnostic route. The stents will be developed to function as radiofrequency antennas, with embedded micro pressure sensors and microelectronic chips to wirelessly sense and transmit renal pressure. The device will be prototyped using microsystems technology available at UBC. This novel stent technology will allow kidney stone patients to check the status using a portable monitor at home, giving an alarm for the need of further diagnosis and necessary treatment by urologists. The research results are anticipated to promote different types of stents and other implants to acquire perceptual features for a wide range of medical applications beyond the urologic area.