Lithotripsy of urinary stones by vortex waves: improving a useful treatment

Abstract

INTRODUCTION AND OBJECTIVE: Our objective is the design, construction and validation of a prototype for the optimized fragmentation of kidney stones using mechanical vortex waves generated with a large-aperture piezoelectric emitter. The vortex beam is focused on stones to produce torques, shear stresses and high internal tensions that fragment these stones much more efficiently than current techniques. Since the generation of shear stress is more efficient using vortex beams, the amplitudes of the ultrasonic field necessary to fragment the stones are much lower than in current extracorporeal shock wave lithotripsy techniques, thus minimizing undesirable effects on soft tissues such as hemorrhages in surrounding tissues or damage due to cavitation. METHODS: After the creation of the device, we proceeded with the first experiments. In vitro testing with solid phantoms to quantify the capacity of the system to fragment stones under laboratory conditions for solid phantoms of different hardness and elasticity. We decided to work with a single size phantom, with a cylindrical shape and dimensions of 12 mmx6mm.Theexperimentscarriedoutwith phantoms were a total of 27 experiments, developed over 87 hours. RESULTS: The results obtained in this experimental phase let us conclude that the use of vortices accelerates the treatment and achieves a higher speed of destruction of the stones compared to the conventional method. Time is a critical parameter in these experiments, and it is very important to note that with the use of vortices the duration of the experiments is greatly reduced. Particularly, we observed that the treatment time is reduced by approximately half and that fragments are tiny, in the form of fine sand of less than 0.050 mm, which would facilitate their natural expulsion. Fragmentation of the stone into large pieces has not been observed. It is possible to reduce the frequency of the therapy beam from 1.1 MHz to less than 500 kHz, to further increase the speed at the cost of producing somewhat larger fragments. CONCLUSIONS: We have built the first Spanish ultrasonic lithotripter device, and the first on a global scale by using vortex beam-based technology. The use of vortices ensures speed and fine sand destruction of urinary stones without damage to healthy tissue because the proposed technique uses pulses with less mechanical amplitude, which would always be safer.

@inproceedings{BeviaAUA2025lithovortex,
 author = {Alberto Budía Alba and Brenda Morant Ferrando and Pilar Bahilo Mateu and Álvaro Josébeviá Romero and Francisco Quereda Flores and Javier Pérez Ardavín and Enrique González-Mateo and Sergio Maldonado-Ortega and Daniel Sanz-Montrull and Alejandro Cebrecos and Alicia Carrión and Francisco Camarena and César D. Vera-Donoso and Noé Jiménez},
 booktitle = {AUA 2025: 2025 Annual Meeting of the American Urological Association (AUA), Las Vegas, USA. 26-29 April},
 doi = {https://doi.org/10.1097/01.JU.0001110072.52045.9d.20},
 editor = {Journal of Urology},
 isbn = {ISSN: 0001-4966},
 month = {05},
 number = {5S},
 organization = {American Urological Association},
 pages = {e1022-e1023},
 publisher = {Lippincott Williams \& Wilkins},
 series = {Poster},
 title = {Lithotripsy of urinary stones by vortex waves: improving a useful treatment},
 url = {https://www.auajournals.org/doi/10.1097/01.JU.0001110072.52045.9d.20},
 volume = {213},
 year = {2025}
}