MP29-11: Feasibility of burst wave lithotripsy and ultrasonic propulsion to expel small, asymptomatic, renal stones
Saturday, May 4, 2024 9:30 AM to 11:30 AM · 2 hr. (US/Central)
302B
Abstract
Information
Full Abstract and Figures
Author Block
Arturo E. Holmes*, Mathew D. Sorensen, Barbrina Dunmire, Jeff Thiel, Barbara H. Burke, Christina Popchoi, John C. Kucewicz, Yak-Nam Wang, Stephanie Totten, Adam D. Maxwell, M. Kennedy Hall, Seattle, WA, James E. Lingeman, Indianapolis, IN, Alana C. Desai, Branda Levchak, Claire C. Yang, Michael R. Bailey, Jonathan D. Harper, Seattle, WA
Introduction
The feasibility of burst wave lithotripsy (BWL) and ultrasonic propulsion to noninvasively fragment and expel small, asymptomatic, renal stones in awake subjects is being tested. A previous randomized control trial reported that removal of secondary, small, asymptomatic renal stones during surgery for a primary stone reduced relapse by 82% (Sorensen et al., NEJM, 2022;387:506-13). Our objective was to treat small asymptomatic stones with BWL and ultrasonic propulsion in a clinic-based setting without anesthesia.
Methods
Participants with up to three, 2-7 mm stones in one kidney seen on computerized tomography (CT) within 90 days were consented and screened to assure targetability with the ultrasound device. Untreated infection or inability to hold anticoagulation were exclusions. Transcutaneous ultrasound imaging with BWL therapy to break stones and ultrasonic propulsion to reposition fragments were applied to awake subjects for a 30-minute total exposure under continuous cardiac monitoring. Pain was assessed immediately before and after the procedure. Postoperative urine samples were graded on a published hematuria score (0-10). Participants were asked to strain their urine and they were contacted weekly for 3 weeks to assess for adverse events (AEs) and fragment passage. The primary outcome was stone free on CT 90 days post procedure. Secondary outcomes included change in stone volume, fragment passage, and AEs.
Results
Thirteen participants have been enrolled; 4 failed screening because no stones were seen (2), stones were too large (1), and the individual chose bilateral surgery instead (1). Nine participants with 11 stones received the research procedure: all tolerated treatment. Seven participants have received follow-up CT to date, 2 were stone free with 3 stones completely cleared. Mean reduction in stone volume was 70 ± 25%. Video recordings of the research procedures showed stone fragmentation and repositioning. Six of 9 provided photographs of passed fragments. AEs were mild and self-resolving and included: hematuria (6, average score 2.0 ± 1.6), renal colic (1), back pain (3), urinary urgency (1), and change in urinary frequency (1). One participant with a history of urinary tract infections was given antibiotics post procedure despite a negative urinalysis. All pain scores were zero, except one 2, which the participant attributed to positioning.
Conclusions
It is feasible to remove small, asymptomatic, renal stones noninvasively in awake participants with only mild transient AEs. BWL and ultrasonic propulsion may in the not-too-distant future offer a way to prophylactically remove small stones before they require an emergency department visit or surgery.
Source Of Funding
Work supported by NIH NIDDK P01 DK043881.
Author Block
Arturo E. Holmes*, Mathew D. Sorensen, Barbrina Dunmire, Jeff Thiel, Barbara H. Burke, Christina Popchoi, John C. Kucewicz, Yak-Nam Wang, Stephanie Totten, Adam D. Maxwell, M. Kennedy Hall, Seattle, WA, James E. Lingeman, Indianapolis, IN, Alana C. Desai, Branda Levchak, Claire C. Yang, Michael R. Bailey, Jonathan D. Harper, Seattle, WA
Introduction
The feasibility of burst wave lithotripsy (BWL) and ultrasonic propulsion to noninvasively fragment and expel small, asymptomatic, renal stones in awake subjects is being tested. A previous randomized control trial reported that removal of secondary, small, asymptomatic renal stones during surgery for a primary stone reduced relapse by 82% (Sorensen et al., NEJM, 2022;387:506-13). Our objective was to treat small asymptomatic stones with BWL and ultrasonic propulsion in a clinic-based setting without anesthesia.
Methods
Participants with up to three, 2-7 mm stones in one kidney seen on computerized tomography (CT) within 90 days were consented and screened to assure targetability with the ultrasound device. Untreated infection or inability to hold anticoagulation were exclusions. Transcutaneous ultrasound imaging with BWL therapy to break stones and ultrasonic propulsion to reposition fragments were applied to awake subjects for a 30-minute total exposure under continuous cardiac monitoring. Pain was assessed immediately before and after the procedure. Postoperative urine samples were graded on a published hematuria score (0-10). Participants were asked to strain their urine and they were contacted weekly for 3 weeks to assess for adverse events (AEs) and fragment passage. The primary outcome was stone free on CT 90 days post procedure. Secondary outcomes included change in stone volume, fragment passage, and AEs.
Results
Thirteen participants have been enrolled; 4 failed screening because no stones were seen (2), stones were too large (1), and the individual chose bilateral surgery instead (1). Nine participants with 11 stones received the research procedure: all tolerated treatment. Seven participants have received follow-up CT to date, 2 were stone free with 3 stones completely cleared. Mean reduction in stone volume was 70 ± 25%. Video recordings of the research procedures showed stone fragmentation and repositioning. Six of 9 provided photographs of passed fragments. AEs were mild and self-resolving and included: hematuria (6, average score 2.0 ± 1.6), renal colic (1), back pain (3), urinary urgency (1), and change in urinary frequency (1). One participant with a history of urinary tract infections was given antibiotics post procedure despite a negative urinalysis. All pain scores were zero, except one 2, which the participant attributed to positioning.
Conclusions
It is feasible to remove small, asymptomatic, renal stones noninvasively in awake participants with only mild transient AEs. BWL and ultrasonic propulsion may in the not-too-distant future offer a way to prophylactically remove small stones before they require an emergency department visit or surgery.
Source Of Funding
Work supported by NIH NIDDK P01 DK043881.