MP89-16 WHAT IS THE BEST WAY TO POPCORN? ROLE OF FLOW RATE, FIBER SIZE, FIBER TO STONE DISTANCE, AND CALYCEAL SIZE ON SUB-MILLIMETER FRAGMENTATION

Abstract

You have accessJournal of UrologyStone Disease: Surgical Therapy VI1 Apr 2018MP89-16 WHAT IS THE BEST WAY TO POPCORN? ROLE OF FLOW RATE, FIBER SIZE, FIBER TO STONE DISTANCE, AND CALYCEAL SIZE ON SUB-MILLIMETER FRAGMENTATION Ali H Aldoukhi, William W Roberts, Timothy L Hall, and Khurshid R Ghani Ali H AldoukhiAli H Aldoukhi More articles by this author , William W RobertsWilliam W Roberts More articles by this author , Timothy L HallTimothy L Hall More articles by this author , and Khurshid R GhaniKhurshid R Ghani More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2018.02.2956AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Non-contact holmium laser lithotripsy (popcorning) during ureteroscopy (URS) is performed when the laser fiber is activated away from the stone in a calyx, resulting in motion and stone fragmentation. Optimal parameters affecting stone breakdown for this technique are not fully understood. The aim of this in vitro study was to investigate the effect of flow rate, fiber size, fiber to stone distance, and calyceal model size on sub-millimeter fragmentation (i.e. dusting effect). METHODS Ten BegoStones (15:3 composition; 1900 Hounsfield unit; 3 x 3 x 1.3 mm size) were placed in a test tube (12x75 mm) to simulate a renal calyx. A 200 μm fiber (Flexiva 200, Boston Scientific) was placed in the working channel of a URS (LithoVue, Boston Scientific) via a 3D positioning system to popcorn the stones via a 120W holmium laser (P120, Lumenis). A setting of 0.5J x 80Hz was used for all experiments, and conducted for a total duration of 3 minutes done in 30 second intervals. Fiber to stone distance differences were studied with the fiber placed 0, 1-2 and 3-4 mm away from the stone surface; 1-2 mm was the default for all other experiments. Flow rates studied were 1L irrigation bag at 60 cm (7-8 mL/min), 100 cm (14-15mL/min), and 100 cm + 150 mmHg pressure (38-40 mL/min); 14-15mL/min was the default for all other experiments. Custom designed glass models were used to assess calyceal sizes (11, 15 and 19 mm). A 365 μm fiber (Flexiva 365) was compared to a 200 μm fiber. The primary outcome was percentage of fragments <1 mm. RESULTS Using the 200 μm laser fiber led to better submillimeter fragmentation results than when using the 365 μm fiber (68.5% vs 50.3%, p <0.05). Similarly, the 11 mm calyceal model and shorter fiber to stone distance (0 mm) had significantly better fragmentation outcomes (p <0.05) (Figure 1). A higher flow rate of 38-40 mL/min led to larger fragments when popcorning (p <0.05). CONCLUSIONS A smaller laser fiber diameter, reduced stone to fiber distance, and smaller calyceal model sizes improved submillimeter fragmentation results when popcorning in an in vitro model. In clinical practice, displacing the stone into a smaller sized calyx, and avoiding high pressure flow rates may improve the efficiency of the technique and lead to a better dusting technique. © 2018FiguresReferencesRelatedDetails Volume 199Issue 4SApril 2018Page: e1211-e1212 Advertisement Copyright & Permissions© 2018MetricsAuthor Information Ali H Aldoukhi More articles by this author William W Roberts More articles by this author Timothy L Hall More articles by this author Khurshid R Ghani More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...