AUA 2019: A Pilot Trial to Evaluate a High-Resolution, Non-Invasive Urodynamic Study to Monitor Electrical Activity of the Human Bladder

Chicago, IL (UroToday.com) During this moderated poster session a variety of novel techniques for evaluating and treating patients with neurogenic bladders. Urodynamic studies are the standard for measuring intravesical pressures and bladder function during filling and emptying, however, this still remains an invasive and uncomfortable procedure to perform. Less invasive and less morbid means to obtain this same diagnostic data has long been desired, particularly by those urologists caring for more complex or pediatric patients. With this study, the authors sought to evaluate the quality of a novel and external technique to measure physiologic changes in the bladder.

By collaborating with biomedical engineers and translational scientists, they developed a pilot study utilizing specialized external electrodes. As this was a preliminary evaluation of this potentially new urodynamic study, they enrolled ten healthy individuals, 7 female, and 3 male, between the ages of 29-42 to determine if reliable and reproducible changes in readings from these electrodes could be observed. During the procedure, eight external electrodes (Ambu Blue Sensor N) are placed on the patient's skin (6 in the suprapubic region and 2 on the left flank). A software program, Python, was utilized to decrease noise artifact. This study was inspired and made possible by new techniques that can quantify wave like phenomena from multi electrode cutaneous records, and measure them with respect to frequency, velocity, and directionality.1 Wave propagation between the electrodes were then collected and analyzed during three phases: Storage (for 5 minutes and 30 seconds), voluntary voiding, and post-voiding (for 5 minutes). They were primarily looking to identify sustained waves and variations in wave speed that could be correlated with these three phases.

In regards to the sustained waves, they were able to appreciate fairly consistent results within the male and female groups and between phases. The female patients during the three phases (storage, voiding, post voiding) had an average of sustained waves appreciated of 71% (+/-5), 74% (+/-6), 73% (+/-5). The male patient during the three phases had an average of sustained waves appreciated of 66% (+/-3), 68% (+/-3), 67% (+/-3).

For grouping and analyzing wave speed, they used histograms, with five different categories: 0-2, 2-4, 4-6, 6-8, 8-9.5 mm/sec. By doing so, and comparing the speed between all of ten tested subjects, they appreciated a trend of decreased wave speed during the voluntary voiding phase. Because of these trends and consistencies of the average sustained waves and the wave speed the authors concluded that these patterns could potentially differentiate between changes in electrical activity representing different bladder dynamics, specifically male vs. female and storage vs. voiding phases.

The ability to measure and assess bladder function via an external means is a very exciting frontier. Although this still very early in development, the potential for follow up studies is particularly robust. Increasing study size, including patients with neurogenic bladder or other voiding dysfunction, combining with ultrasound for measured bladder volume during storage, volume voided, and ultimately comparing and correlating external electrical wave patterns with detrusor pressures during simultaneous urodynamics testing (which the authors reported they plan to do) may bring us even closer to a new, non-invasive UDS.


Presented by: Sanghee Lee, MD, Department of Urology and Division of Pediatric Urology, University of California San Diego, San Diego, California

Written by: Ross Moskowitz, MD; Assistant Clinical Professor of Urology, University of California Irvine Medical Center; @rossmosk1 at the American Urological Association's 2019 Annual Meeting (AUA 2019), May 3 – 6, 2019 in Chicago, Illinois

References:
1. Gharibans, AA, Kim S, Kunkel DC, and Coleman TP. High-Resolution Electrogastrogram: A Novel Noninvasive Method for Determining Gastric Slow-Wave Direction and Speed. IEEE Transactions on Biomedical Engineering, 2017. 64(4), 807-815.
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