PD54-09 SIGNIFICANT CONTRIBUTION OF CAVITATION TO DUSTING STONE DAMAGE IN LASER LITHOTRIPSY

Abstract

You have accessJournal of UrologyStone Disease: Surgical Therapy IV (PD54)1 Sep 2021PD54-09 SIGNIFICANT CONTRIBUTION OF CAVITATION TO DUSTING STONE DAMAGE IN LASER LITHOTRIPSY Derek Ho, Junqin Chen, Gaoming Xiang, Patrick Whelan, Glenn Preminger, Michael Lipkin, and Pei Zhong Derek HoDerek Ho More articles by this author , Junqin ChenJunqin Chen More articles by this author , Gaoming XiangGaoming Xiang More articles by this author , Patrick WhelanPatrick Whelan More articles by this author , Glenn PremingerGlenn Preminger More articles by this author , Michael LipkinMichael Lipkin More articles by this author , and Pei ZhongPei Zhong More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002081.09AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Rapid vaporization of fluid at the fiber tip during Holmium (Ho):YAG laser lithotripsy (LL) causes the formation of a vapor bubble that improves laser transmission to the stone. We have recently demonstrated that the collapse of cavitation bubbles contributes to stone damage in fragmenting mode during LL. Here, we investigate the contribution of bubble collapse to stone damage in dusting mode during LL. METHODS: Artificial BegoStone samples were polished, soaked for 24 hours, and then treated using the dusting mode (0.2 J, 20 Hz) from a clinical Ho:YAG lithotripter (H Solvo 35-watt laser, Dornier MedTech). Stones were treated in water and in air to differentiate the effect of cavitation from photothermal ablation. The laser fiber was oriented perpendicularly to the sample surface at standoff distance (SD) of either 0 or 0.5 mm from the stone. In addition, we devised a novel counter-plate setup (Fig. 1a) during treatment in water (SD = 0.5 mm) to distract the collapse of LL-generated bubble away from the stone. Resultant crater volumes and geometry were quantified using optical coherence tomography (OCT, OQ Labscope, Lumedica) following treatment with varying number of laser pulses (15 – 1000). RESULTS: Stones treated in water under non-contact (SD = 0.5 mm) resulted in significantly larger and wider craters compared to those treated with the fiber in contact (SD = 0 mm) with the stone (Fig. 1b-d blue and purple lines). Stones treated in air resulted in negligible craters compared to their counterparts in water regardless of SD (Fig. 1b-d warm vs. cool colored lines). The counter-plate dampened the bubble collapse toward the stone surface and significantly reduced the crater damage in water at SD = 0.5 mm (Fig. 1b-d black line). CONCLUSIONS: We have demonstrated in dusting mode during LL that repeated bombardments of the collapsing bubbles toward the stone surface is a major contributor of stone damage, in contrast to photothermal ablation. This finding has significant implications for optimizing the treatment strategy in dusting mode – i.e., non-contact operation at a short SD is critical for improving stone damage efficiency. Source of Funding: This project is supported by the National Institute of Health (NIH) through grants P20 DK123970 and R37 DK052985. DH is supported by the NIH (K12 DK100024) © 2021 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 206Issue Supplement 3September 2021Page: e926-e926 Advertisement Copyright & Permissions© 2021 by American Urological Association Education and Research, Inc.MetricsAuthor Information Derek Ho More articles by this author Junqin Chen More articles by this author Gaoming Xiang More articles by this author Patrick Whelan More articles by this author Glenn Preminger More articles by this author Michael Lipkin More articles by this author Pei Zhong More articles by this author Expand All Advertisement Loading ...