Burst Wave Lithotripsy for the Treatment of Ureteral Calculi

DESCRIPTION provided by applicant Significance Urinary tract stones pose a significant healthcare burden with costs to the US exceeding $ billion annually The impact of stone disease on the healthcare system is expected to continue to grow as risk factors such as diabetes and obesity become more prevalent Ureteral stones in particular pose a management challenge as they are often symptomatic and spontaneous passage is a strong function of stone size and location Watchful waiting in combination with expulsion therapy is the first line approach but can lead to repeat physician and or emergency department visits lost productivity and stress on the patient For active intervention extracorporeal shock wave lithotripsy SWL often requires repeat or secondary procedures to achieve stone free status Ureteroscopy a minimally invasive procedure has greater stone free rates than SWL but higher complication rates Technology Burst wave lithotripsy BWL is a novel noninvasive method of stone fragmentation that has the potential to significantly improve the management of ureteral stones BWL uses multi cycle low amplitude pulses of ultrasound rather than shock waves to noninvasively induce stone fracture This approach has the potential to reduce the risk of injury procedural complications and additional procedures as well as result in a significant reduction in procedural time and cost Furthermore the low pulse pressure amplitude used may preclude the need for anesthesia providing an attractive alternative to watchful waiting Preliminary Data In vitro studies have shown the technology is capable of breaking all common types of stones found in humans Results also show that the fragment size can be controlled by altering the ultrasound frequency to produce small fragments likely to spontaneously pass without further symptoms Preliminary studies indicate the pressure levels required to break stones are significantly below the pressure levels required to induce renal injury in a porcine animal study Specific Aims This is a fast track proposal that will use Phase I to address the technical question of how BWL parameters should be altered to treat a stone obstructed within a ureter compared to a stone free in a water bath This will require assembly of a BWL transducer and amplifier Phase I Aim and in vitro studies to establish the pressure level and dose time required to break stones within a ureteral phantom Phase I Aim Phase II identifies the acoustic windows and critical structures exposed while targeting ureteral stones Phase II Aim and designs the commercial prototype transducer specific for those windows and operating the acoustic parameters identified in Phase I Phase II Aim The BWL system will be guided by an ultrasound imaging system with specialized algorithms to enhance targeting and detect cavitation to monitor and control for injury Phase II Aim The safety and efficacy of the developed system will be tested in a porcine animal model Phase II Aims PUBLIC HEALTH RELEVANCE One in Americans will have urinary stones in their lifetime Most of the $ B annual cost of this disease is visits to the emergency department imaging and surgery with over visits a year to the emergency department for ureteral stones alone This proposal aims to develop burst wave lithotripsy BWL a promising new method to fragment stones licensed by SonoMotion Inc as a safer and more effective treatment option for ureteral stones