Focused Ultrasound Therapy
Focused ultrasound is a noninvasive, therapeutic technology with the potential to improve the quality of life and decrease the cost of care for patients with kidney stones. This novel technology focuses beams of ultrasonic energy precisely and accurately on targets deep in the body without damaging surrounding normal tissue.
The FDA has granted De Novo clearance for the Companys Stone ClearTM device for anesthesia free treatment of post-lithotripsy stone fragments. This was reviewed in a study published in the Journal of Urology.
How it Works
There are two mechanisms of action where this technology can help those with kidney stones.
The first mechanism is the ability to propel stones in the genitourinary track, which can be very helpful in patients with multiple stones or for those who have had extracorporeal shock wave lithotripsy (also referred to as ESWL), where there is the potential for the stone fragments to locate in the lower pole. As the energy is applied near the edge of the stone, there is an acoustic wave that spreads, resulting for stone movement. Initial clinical trials have been done, but further research is needed before widespread adoption can occur.
A second mechanism of action is to use the energy in focused ultrasound to mechanically fragment the kidney stones into smaller pieces. These smaller pieces can pass through the urinary drainage system and exit in the urine. This fragmentation has been done in the research lab, but it has not yet been accomplished in human clinical trials. The SonoMotion’s Break Wave device is in the process of ongoing evaluation.
Ongoing work continues is being done by a spin-off company from the University of Washington, SonoMotion, on these ideas.
Advantages
For certain patients, focused ultrasound could provide a noninvasive alternative to surgery with less risk of complications and lower cost. It has the ability to noninvasively relocate kidney stones, and treatment does not require any nephrotoxic or ionizing radiation components. Focused ultrasound can also be repeated, if needed.
Clinical Trials
A multi-center clinical trial is using low intensity focused ultrasound to break up kidney stones.
Regulatory Approval and Reimbursement
Focused ultrasound treatment of kidney stones is not yet approved by regulatory bodies or covered by medical insurance companies.
Notable Papers
Li W, Feng T, Meng T, Guo G, Tu J, Zhang D, Ma Q. Steerable ultrasonic propulsion of rigid objects based on circular pressure modulation of a focused sectorial transducer array. Ultrasonics. 2025 Jan;145:107475. doi: 10.1016/j.ultras.2024.107475. Epub 2024 Sep 14. PMID: 39293232
Sorensen M , Dunmire B , Thiel J , Cunitz BW , Burke BH, Levchak BJ , Popchoi C , Holmes AE , Kucewicz JC , Hall MK , Dighe M , Dai JC , Cormack FC , Liu Z, Bailey MR , Porter MP , Harper JD. Randomized Controlled Trial of Ultrasonic Propulsion-Facilitated Clearance of Residual Kidney Stone Fragments vs Observation. J Urol. 2024 Aug 14:101097JU0000000000004186. doi:10.1097/JU.0000000000004186. PMID: 39146526
Li W, Feng T, Meng T, Guo G, Tu J, Zhang D, Ma Q. Steerable ultrasonic propulsion of rigid objects based on circular pressure modulation of a focused sectorial transducer array. Ultrasonics. 2024 Sep 14;145:107475. doi: 10.1016/j.ultras.2024.107475. PMID: 39293232
Biasiori-Poulanges L, Lukić B, Supponen O. Cavitation cloud formation and surface damage of a model stone in a high-intensity focused ultrasound field. Ultrason Sonochem. 2023 Dec 22;102:106738. doi: 10.1016/j.ultsonch.2023.106738. PMID: 38150955
Maxwell AD, Kim GW, Furrow E, Lulich JP, Torre M, MacConaghy B, Lynch E, Leotta DF, Wang YN, Borofsky MS, Bailey MR. Development of a burst wave lithotripsy system for noninvasive fragmentation of ureteroliths in pet cats. BMC Vet Res. 2023 Sep 2;19(1):141. doi: 10.1186/s12917-023-03705-1. PMID: 37660015
Hall MK, Thiel J, Dunmire B, Samson PC, Kessler R, Sunaryo P, Sweet RM, Metzler IS, Chang HC, Gunn M, Dighe M, Anderson L, Popchoi C, Managuli R, Cunitz BW, Burke BH, Ding L, Gutierrez B, Liu Z, Sorensen MD, Wessells H, Bailey MR, Harper JD. First Series Using Ultrasonic Propulsion and Burst Wave Lithotripsy to Treat Ureteral Stones. J Urol. 2022 Nov;208(5):1075-1082. doi: 10.1097/JU.0000000000002864. Epub 2022 Nov 1.
Harper JD, Lingeman JE, Sweet RM, Metzler IS, Sunaryo PL, Williams JC Jr, Maxwell AD, Thiel J, Cunitz BW, Dunmire B, Bailey MR, Sorensen MD. Fragmentation of Stones by Burst Wave Lithotripsy in the First 19 Humans. J Urol. 2022 May;207(5):1067-1076. doi: 10.1097/JU.0000000000002446. Epub 2022 Mar 21.
Ghanem MA, Maxwell AD, Kreider W, Cunitz BW, Khokhlova VA, Sapozhnikov OA, Bailey MR. Field Characterization and Compensation of Vibrational Nonuniformity for a 256-Element Focused Ultrasound Phased Array. IEEE Trans Ultrason Ferroelectr Freq Control. 2018 Sep;65(9):1618-1630. doi: 10.1109/TUFFC.2018.2851188.
Oweis GF, Dunmire BL, Cunitz BW, Bailey MR. 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;2015:2576-9. doi: 10.1109/EMBC.2015.7318918.
Harper JD, Cunitz BW, Dunmire B, Lee FC, Sorensen MD, Hsi RS, Thiel J, Wessells H, Lingeman JE, Bailey MR. First in Human Clinical Trial of Ultrasonic Propulsion of Kidney Stones. J Urol. 2016 Apr;195(4P1):956-64. doi: 10.1016/j.juro.2015.10.131.
Ikeda T, Yoshizawa S, Koizumi N, Mitsuishi M, Matsumoto Y. Focused Ultrasound and Lithotripsy. Adv Exp Med Biol. 2016;880:113-29. doi: 10.1007/978-3-319-22536-4_7. Review.
Pfau A, Eckardt KU, Knauf F. [Diagnosis and treatment of nephrolithiasis. What is established?]. Internist (Berl). 2015 Dec;56(12):1361-8. doi: 10.1007/s00108-015-3758-0. Review. German.
Oweis GF, Dunmire BL, Cunitz BW, Bailey MR. 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;2015:2576-9. doi: 10.1109/EMBC.2015.7318918.
Abrol N, Kekre NS. Focused ultrasound guided relocation of kidney stones. Indian J Urol. 2015 Jan-Mar;31(1):28-32. doi: 10.4103/0970-1591.139577.
Wang YN, Simon JC, Cunitz BW, Starr FL, Paun M, Liggitt DH, Evan AP, McAteer JA, Liu Z, Dunmire B, Bailey MR. Focused ultrasound to displace renal calculi: threshold for tissue injury. J Ther Ultrasound. 2014 Mar 31;2:5. doi: 10.1186/2050-5736-2-5.
Connors BA, Evan AP, Blomgren PM, Hsi RS, Harper JD, Sorensen MD, Wang YN, Simon JC, Paun M, Starr F, Cunitz BW, Bailey MR, Lingeman JE. Comparison of tissue injury from focused ultrasonic propulsion of kidney stones versus extracorporeal shock wave lithotripsy. J Urol. 2014 Jan;191(1):235-41. doi: 10.1016/j.juro.2013.07.087.
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