2107 FOCUSED ULTRASOUND APPLICATION TO REPOSITION KIDNEY STONES AND FACILITATE PASSAGE OF RESIDUAL FRAGMENTS

Abstract

Listen

Translate article

You have accessJournal of UrologyStone Disease: New Technology1 Apr 20102107 FOCUSED ULTRASOUND APPLICATION TO REPOSITION KIDNEY STONES AND FACILITATE PASSAGE OF RESIDUAL FRAGMENTS Anup Shah, Mathew Sorensen, Jonathan Harper, Bryan Cunitz, Wei Lu, and Michael Bailey Anup ShahAnup Shah More articles by this author , Mathew SorensenMathew Sorensen More articles by this author , Jonathan HarperJonathan Harper More articles by this author , Bryan CunitzBryan Cunitz More articles by this author , Wei LuWei Lu More articles by this author , and Michael BaileyMichael Bailey More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2010.02.2194AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Lower pole kidney stones have lower rates of stone clearance after shock wave lithotripsy (SWL) and ureteroscopic treatment compared to other stone locations because of dependant positioning and difficult access. Residual stone fragments often lead to additional morbidity and need for secondary surgery. We describe the use of acoustic force and streaming created by transcutaneous focused ultrasound to manipulate the location of stone fragments within the collecting system in order to facilitate stone clearance. METHODS A newly developed focused ultrasound therapy probe consists of an 8-element annular array with a nominal frequency of 2.0 MHz, acoustic power output of 5-20W, and programmable focal depth of 4.5-8.5 cm. There is an opening in the center of the therapy probe for an HDI P4-2 imaging probe to provide ultrasound image guidance in a 2D plane. Artificial and human stones were placed into the lower pole of transparent kidney phantoms and live porcine kidneys using retrograde ureteroscopy. Focused ultrasound was applied. Stone motion was observed visually in the kidney phantom and using both diagnostic ultrasound and fluoroscopy in the porcine kidneys. Any tissue effects caused by focused ultrasound were assessed. RESULTS All stones placed in the kidney phantoms and live porcine kidneys were seen to move. Stone size ranged from 2 mm to 6 mm in maximal dimension. Stone velocities were on the order of 1 cm/s. Stone displacement distance was up to 3 cm and operators could generally control the direction of stone movement. No evidence of thermal necrosis or mechanical damage of renal tissue was observed on gross and microscopic examination. CONCLUSIONS Focused ultrasound can be used to move stones within the collecting system and may be able to improve rates of lower pole stone fragment clearance. Other applications for this new technology may include adjunctive use with medical expulsive therapy, repositioning of obstructing ureteropelvic junction stones, and ensuring complete clearance of infectious stones. Seattle, WA© 2010 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 183Issue 4SApril 2010Page: e819 Advertisement Copyright & Permissions© 2010 by American Urological Association Education and Research, Inc.MetricsAuthor Information Anup Shah More articles by this author Mathew Sorensen More articles by this author Jonathan Harper More articles by this author Bryan Cunitz More articles by this author Wei Lu More articles by this author Michael Bailey More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...