PD6-05 EVALUATING AN IMPLANTABLE WIRELESS PRESSURE SENSOR FOR USE IN THE URINARY TRACT

Abstract

You have accessJournal of UrologyTechnology & Instruments: Surgical Education & Skills Assessment I1 Apr 2014PD6-05 EVALUATING AN IMPLANTABLE WIRELESS PRESSURE SENSOR FOR USE IN THE URINARY TRACT Brian Le, Alberto Colombo, Harry Rowland, and Kevin McVary Brian LeBrian Le More articles by this author , Alberto ColomboAlberto Colombo More articles by this author , Harry RowlandHarry Rowland More articles by this author , and Kevin McVaryKevin McVary More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2014.02.513AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Pressure information is an essential component of urodynamics and the evaluation for obstructive uropathy. Current methods of obtaining pressure information require a direct wired connection, which causes discomfort and limits repeated measurements and widespread use. Here we evaluate a novel wireless induction technology that would allow wireless measurements to be taken through tissues using a self-contained microcircuit with an external reader. METHODS We conducted in vitro and animal experiments to evaluate the signal strength, accuracy and feasibility of a wireless pressure sensing system in the GU tract. Prior to implantation, bench tests were carried out to evaluate the sensors’ pressure reading accuracy at a range of different pressures and distances. In animal trials, rats were anesthetized and a cystotomy was made to insert a self-contained Induction-Capacitance (LC) circuit into the bladder and then sutured closed. A calibrated catheter with a pressure gauge was inserted into the bladder via the urethra. The bladder was cycled from empty to capacity several times while readings were obtained. All experiments were approved by the Institution’s Animal Safety Board. RESULTS Bench tests on wireless sensors showed accuracy within +/- 1.5 mmHg up to 9 cm distance in the urinary tract pressure range of 0 to 50 mm Hg. When the sensor was inserted in the bladder of rats, the sensors responded to an artificial increase in bladder pressure with the emission of a proportionally decreasing resonant frequency signals (figure 1). As expected a declining resonant frequency is recorded with increasing pressure. A linear regression could be detected with r=-0.75. CONCLUSIONS Wireless sensors can be effectively used in the urinary system and can provide a robust signal through tissues and in a high salt environment in a predictable fashion. We expect that the concordance with wired readings will greatly increase with the next generation of wireless sensors with ceramic encapsulation that will prevent frequency drifting and thus more accuracy. © 2014FiguresReferencesRelatedDetails Volume 191Issue 4SApril 2014Page: e131-e132 Advertisement Copyright & Permissions© 2014MetricsAuthor Information Brian Le More articles by this author Alberto Colombo More articles by this author Harry Rowland More articles by this author Kevin McVary More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...