Ten percent of the U.S. population will develop kidney stones. Three million Americans seek treatment each year, and total treatment cost is over $2B. Initial success rates range from ~70% to greater than 90% depending on the type of treatment performed, but stones will recur in half the patients within 5 years. Follow- up surgical management of stones is complex and individualized but expends significant resources, creates additional discomfort and can expose the patient to X-rays many times. Small stone fragments in the renal pelvis have a good chance of passing naturally, but fragments located in the lower calyces are more likely to remain and become problematic. We have developed a handheld pulsed-ultrasound device to non-invasively expel stone fragments (or small stones) from the kidney. We have also developed a unique ultrasound imaging method to dramatically enhance the visualization of kidney stones, which provides a safe alternative to the ionizing radiation of plane X-ray and computerized tomography (CT). A prototype device has been engineered from a commercially available diagnostic ultrasound imager and probe. Preliminary results in animal models show we can localize and safely repositioning stones from the lower calyx to the ureteropelvic juncture (UPJ) in less than 5 minutes, a procedure that could easily be completed during an office visit. The objective of this proposal using human subjects is to assess the ability of this device to reposition stone fragments. We will first measure, imaging accuracy of enhanced ultrasound localization compared to CT as the gold standard. In partnership with a regulatory consultant, we will prepare an application to the U.S. Food and Drug Administration (FDA) for an Investigational Device Exemption (IDE) to test the therapeutic strategy of repositioning stones in human subjects. The long-term goal is to provide urologists with a new non-invasive surgical option to clear stone fragments and small stones from the kidney. This device would be used to clear residual fragments remaining after shock wave lithotripsy (or invasive stone removal such as ureteroscopy), and could be a means to prophylactically expel small stones from the kidney before they become symptomatic. This stone repositioning device and its complementary stone imaging methodology have the potential to deliver safer, more effective treatments and significantly lower healthcare costs.
The proposal is to transition technology to detect and reposition kidney stones with ultrasound to facilitate stone clearance. As such kidney stone patients who account for 10% of the US population might be spared ionizing radiation of stone detection by x-ray computerized tomography and spared surgery or lithotripsy for initial or follow-on treatment.
|Dunmire, Barbrina; Harper, Jonathan D; Cunitz, Bryan W et al. (2016) Use of the Acoustic Shadow Width to Determine Kidney Stone Size with Ultrasound. J Urol 195:171-7|
|May, Philip C; Bailey, Michael R; Harper, Jonathan D (2016) Ultrasonic propulsion of kidney stones. Curr Opin Urol 26:264-70|
|Harper, Jonathan D; Cunitz, Bryan W; Dunmire, Barbrina et al. (2016) First in Human Clinical Trial of Ultrasonic Propulsion of Kidney Stones. J Urol 195:956-64|
|Lee, Franklin C; Hsi, Ryan S; Sorensen, Mathew D et al. (2015) Renal Vasoconstriction Occurs Early During Shockwave Lithotripsy in Humans. J Endourol 29:1392-5|
|Maxwell, Adam D; Cunitz, Bryan W; Kreider, Wayne et al. (2015) Fragmentation of urinary calculi in vitro by burst wave lithotripsy. J Urol 193:338-44|
|Oweis, Ghanem F; Dunmire, Barbrina L; Cunitz, Bryan W et al. (2015) Non-invasive measurement of the temperature rise in tissue surrounding a kidney stone subjected to ultrasonic propulsion. Conf Proc IEEE Eng Med Biol Soc 2015:2576-9|
|Dunmire, Barbrina; Lee, Franklin C; Hsi, Ryan S et al. (2015) Tools to improve the accuracy of kidney stone sizing with ultrasound. J Endourol 29:147-52|
|Harper, Jonathan D; Dunmire, Barbrina; Wang, Yak-Nam et al. (2014) Preclinical safety and effectiveness studies of ultrasonic propulsion of kidney stones. Urology 84:484-9|
|Connors, Bret A; Evan, Andrew P; Blomgren, Philip M et al. (2014) Comparison of tissue injury from focused ultrasonic propulsion of kidney stones versus extracorporeal shock wave lithotripsy. J Urol 191:235-41|
|Cunitz, Bryan; Dunmire, Barbrina; Paun, Marla et al. (2014) Improved Detection of Kidney Stones Using an Optimized Doppler Imaging Sequence. IEEE Int Ultrason Symp 2014:452-455|
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