V02-01 THE VORTEX EFFECT IN MINI-PCNL: IMPROVED UNDERSTANDING WITH A PHANTOM MODEL & COMPUTATIONAL FLUID DYNAMICS

You have accessJournal of UrologyCME1 Apr 2023V02-01 THE VORTEX EFFECT IN MINI-PCNL: IMPROVED UNDERSTANDING WITH A PHANTOM MODEL & COMPUTATIONAL FLUID DYNAMICS Willian Ito, Dillon Prokop, Crystal Valadon, Bristol Whiles, Donald Neff, David Duchene, and Wilson Molina Willian ItoWillian Ito More articles by this author , Dillon ProkopDillon Prokop More articles by this author , Crystal ValadonCrystal Valadon More articles by this author , Bristol WhilesBristol Whiles More articles by this author , Donald NeffDonald Neff More articles by this author , David DucheneDavid Duchene More articles by this author , and Wilson MolinaWilson Molina More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003232.01AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Minimally invasive percutaneous nephrolithotomy (MIP) was initially discredited with assumptions of difficult stone fragment retrieval because of the equipment’s smaller size. However, in 2008 Nagele et al. described a hydrodynamic phenomenon that allowed stone retrieval without the aid of endoscopic tools. This study aims to describe the physical principles of the “vortex effect” to better understand its applicability in MIP procedures. METHODS: Two acrylic phantom models were built based on the cross-sectional area (CSA) ratio of a MIP nephroscope and access sheaths (15/16F and 21/22F MIP-M™, Karl Storz®). The nephroscope phantom was 10 mm in diameter. The access sheaths had diameters of 14 mm (CSA ratio: 0.69) and 20 mm (CSA ratio: 0.30). The models were adapted to generate hydrolysis, and hydrogen bubbles enhanced flow visualization on a green laser background. After calibration, the experimental flow rate was set to 12.0 mL/sec. Three 30-second trials assessing the flow were performed with each model. Computational fluid dynamic simulations (CFD) were completed to determine the speed and pressure profiles. RESULTS: In both models, as the incoming fluid from the nephroscope phantom unsuccessfully attempted to move toward the collecting system, a stagnation point (SP) was demonstrated. No fluid entered the collecting system phantom. Utilizing the 14 mm sheath, we observed a random generation of several vortices and a pressure gradient (PG) of 114.4 N/m2 between the nephroscope’s tip and SP. When the 20 mm sheath was examined, a significantly smaller PG (19.4 N/m2) and no noticeable vortices were noted. CONCLUSIONS: The speed of the fluid and equipment geometry regulate the pressure gradient and the vortices field, which are responsible for the production of the vortex effect. Considering the same flow rate, a higher ratio between the cross-sectional area of the nephroscope and access sheath results in improved efficiency of the vortex. Source of Funding: None © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e168 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Willian Ito More articles by this author Dillon Prokop More articles by this author Crystal Valadon More articles by this author Bristol Whiles More articles by this author Donald Neff More articles by this author David Duchene More articles by this author Wilson Molina More articles by this author Expand All Advertisement PDF downloadLoading ...