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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; 19:141. [PMID: 37660015 PMCID: PMC10474658 DOI: 10.1186/s12917-023-03705-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 08/24/2023] [Indexed: 09/04/2023] Open
Abstract
BACKGROUND Upper urinary tract stones are increasingly prevalent in pet cats and are difficult to manage. Surgical procedures to address obstructing ureteroliths have short- and long-term complications, and medical therapies (e.g., fluid diuresis and smooth muscle relaxants) are infrequently effective. Burst wave lithotripsy is a non-invasive, ultrasound-guided, handheld focused ultrasound technology to disintegrate urinary stones, which is now undergoing human clinical trials in awake unanesthetized subjects. RESULTS In this study, we designed and performed in vitro testing of a modified burst wave lithotripsy system to noninvasively fragment stones in cats. The design accounted for differences in anatomic scale, acoustic window, skin-to-stone depth, and stone size. Prototypes were fabricated and tested in a benchtop model using 35 natural calcium oxalate monohydrate stones from cats. In an initial experiment, burst wave lithotripsy was performed using peak ultrasound pressures of 7.3 (n = 10), 8.0 (n = 5), or 8.9 MPa (n = 10) for up to 30 min. Fourteen of 25 stones fragmented to < 1 mm within the 30 min. In a second experiment, burst wave lithotripsy was performed using a second transducer and peak ultrasound pressure of 8.0 MPa (n = 10) for up to 50 min. In the second experiment, 9 of 10 stones fragmented to < 1 mm within the 50 min. Across both experiments, an average of 73-97% of stone mass could be reduced to fragments < 1 mm. A third experiment found negligible injury with in vivo exposure of kidneys and ureters in a porcine animal model. CONCLUSIONS These data support further evaluation of burst wave lithotripsy as a noninvasive intervention for obstructing ureteroliths in cats.
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Affiliation(s)
- Adam D Maxwell
- Department of Urology, University of Washington School of Medicine, Seattle, WA, USA
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, WA, USA
| | - Ga Won Kim
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, WA, USA
| | - Eva Furrow
- Department of Veterinary Clinical Sciences, University of Minnesota, St. Paul, MN, USA
| | - Jody P Lulich
- Department of Veterinary Clinical Sciences, University of Minnesota, St. Paul, MN, USA
| | - Marissa Torre
- Department of Veterinary Clinical Sciences, University of Minnesota, St. Paul, MN, USA
| | - Brian MacConaghy
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, WA, USA
| | - Elizabeth Lynch
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, WA, USA
| | - Daniel F Leotta
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, WA, USA
| | - Yak-Nam Wang
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, WA, USA
| | | | - Michael R Bailey
- Department of Urology, University of Washington School of Medicine, Seattle, WA, USA.
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, WA, USA.
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Koukas E, Papoutsakis A, Gavaises M. Numerical investigation of shock-induced bubble collapse dynamics and fluid-solid interactions during shock-wave lithotripsy. ULTRASONICS SONOCHEMISTRY 2023; 95:106393. [PMID: 37031534 PMCID: PMC10114246 DOI: 10.1016/j.ultsonch.2023.106393] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 03/14/2023] [Accepted: 03/28/2023] [Indexed: 06/19/2023]
Abstract
In this paper we investigate the bubble collapse dynamics under shock-induced loading near soft and rigid bio-materials, during shock wave lithotripsy. A novel numerical framework was developed, that employs a Diffuse Interface Method (DIM) accounting for the interaction across fluid-solid-gas interfaces. For the resolution of the extended variety of length scales, due to the dynamic and fine interfacial structures, an Adaptive Mesh Refinement (AMR) framework for unstructured grids was incorporated. This multi-material multi-scale approach aims to reduce the numerical diffusion and preserve sharp interfaces. The presented numerical framework is validated for cases of bubble dynamics, under high and low ambient pressure ratios, shock-induced collapses, and wave transmission problems across a fluid-solid interface, against theoretical and numerical results. Three different configurations of shock-induced collapse applications near a kidney stone and soft tissue have been simulated for different stand-off distances and bubble attachment configurations. The obtained results reveal the detailed collapse dynamics, jet formation, solid deformation, rebound, primary and secondary shock wave emissions, and secondary collapse that govern the near-solid collapse and penetration mechanisms. Significant correlations of the problem configuration to the overall collapse mechanisms were found, stemming from the contact angle/attachment of the bubble and from the properties of solid material. In general, bubbles with their center closer to the kidney stone surface produce more violent collapses. For the soft tissue, the bubble movement prior to the collapse is of great importance as new structures can emerge which can trap the liquid jet into induced crevices. Finally, the tissue penetration is examined for these cases and a novel tension-driven tissue injury mechanism is elucidated, emanating from the complex interaction of the bubble/tissue interaction during the secondary collapse phase of an entrapped bubble in an induced crevice with the liquid jet.
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Affiliation(s)
- Evangelos Koukas
- Department of Mechanical Engineering and Aeronautics, School of Mathematics, Computer Science and Engineering, City University of London, Northampton Square, EC1V 0HB London, UK.
| | - Andreas Papoutsakis
- Department of Engineering, School of Physics Engineering and Computer Science (SPECS), University of Hertfordshire, College Lane Campus, AL10 9AB Hatfield, UK
| | - Manolis Gavaises
- Department of Mechanical Engineering and Aeronautics, School of Mathematics, Computer Science and Engineering, City University of London, Northampton Square, EC1V 0HB London, UK
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Torres-Ortiz D, García-Alcocer G, Loske AM, Fernández F, Becerra-Becerra E, Esparza R, Gonzalez-Reyna MA, Estevez M. Green Synthesis and Antiproliferative Activity of Gold Nanoparticles of a Controlled Size and Shape Obtained Using Shock Wave Extracts from Amphipterygium adstringens. Bioengineering (Basel) 2023; 10:bioengineering10040437. [PMID: 37106624 PMCID: PMC10136038 DOI: 10.3390/bioengineering10040437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Revised: 03/23/2023] [Accepted: 03/25/2023] [Indexed: 04/03/2023] Open
Abstract
In this study, green chemistry was used as a tool to obtain gold nanoparticles using Amphipterygium adstringens extracts as a synthesis medium. Green ethanolic and aqueous extracts were obtained using ultrasound and shock wave-assisted extraction. Gold nanoparticles with sizes ranging between 100 and 150 nm were obtained with ultrasound aqueous extract. Interestingly, homogeneous quasi-spherical gold nanoparticles with sizes between 50 and 100 nm were achieved with shock wave aqueous-ethanolic extracts. Furthermore, 10 nm gold nanoparticles were obtained by the traditional methanolic macerate extraction method. The physicochemical characteristics, morphology, size, stability, and Z potential of the nanoparticles were determined using microscopic and spectroscopic techniques. The viability assay in leukemia cells (Jurkat) was performed using two different sets of gold nanoparticles, with final IC50 values of 87 µM and 94.7 µM, reaching a maximum cell viability decrease of 80% The results do not indicate a significant difference between the cytotoxic effects produced by the gold nanoparticles synthesized in this study and vincristine on normal lymphoblasts (CRL-1991).
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Affiliation(s)
- Daniela Torres-Ortiz
- Facultad de Química, Universidad Autónoma de Querétaro, Cerro de las Campanas s/n, Santiago de Querétaro 76010, Querétaro, Mexico
| | - Guadalupe García-Alcocer
- Facultad de Química, Universidad Autónoma de Querétaro, Cerro de las Campanas s/n, Santiago de Querétaro 76010, Querétaro, Mexico
- Correspondence: (G.G.-A.); (M.E.)
| | - Achim M. Loske
- Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Santiago de Querétaro 76230, Querétaro, Mexico
| | - Francisco Fernández
- Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Santiago de Querétaro 76230, Querétaro, Mexico
| | - Edgardo Becerra-Becerra
- Facultad de Química, Universidad Autónoma de Querétaro, Cerro de las Campanas s/n, Santiago de Querétaro 76010, Querétaro, Mexico
| | - Rodrigo Esparza
- Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Santiago de Querétaro 76230, Querétaro, Mexico
| | - Marlen Alexis Gonzalez-Reyna
- Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Santiago de Querétaro 76230, Querétaro, Mexico
| | - Miriam Estevez
- Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Santiago de Querétaro 76230, Querétaro, Mexico
- Correspondence: (G.G.-A.); (M.E.)
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Todorov LG, Sivaguru M, Krambeck AE, Lee MS, Lieske JC, Fouke BW. GeoBioMed perspectives on kidney stone recurrence from the reactive surface area of SWL-derived particles. Sci Rep 2022; 12:18371. [PMID: 36319741 PMCID: PMC9626463 DOI: 10.1038/s41598-022-23331-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Accepted: 10/29/2022] [Indexed: 11/18/2022] Open
Abstract
Shock wave lithotripsy (SWL) is an effective and commonly applied clinical treatment for human kidney stones. Yet the success of SWL is counterbalanced by the risk of retained fragments causing recurrent stone formation, which may require retreatment. This study has applied GeoBioMed experimental and analytical approaches to determine the size frequency distribution, fracture patterns, and reactive surface area of SWL-derived particles within the context of their original crystal growth structure (crystalline architecture) as revealed by confocal autofluorescence (CAF) and super-resolution autofluorescence (SRAF) microscopy. Multiple calcium oxalate (CaOx) stones were removed from a Mayo Clinic patient using standard percutaneous nephrolithotomy (PCNL) and shock pulse lithotripsy (SPL). This produced approximately 4-12 mm-diameter PCNL-derived fragments that were experimentally treated ex vivo with SWL to form hundreds of smaller particles. Fractures propagated through the crystalline architecture of PCNL-derived fragments in a variety of geometric orientations to form rectangular, pointed, concentrically spalled, and irregular SWL-derived particles. Size frequency distributions ranged from fine silt (4-8 μm) to very fine pebbles (2-4 mm), according to the Wentworth grain size scale, with a mean size of fine sand (125-250 μm). Importantly, these SWL-derived particles are smaller than the 3-4 mm-diameter detection limit of clinical computed tomography (CT) techniques and can be retained on internal kidney membrane surfaces. This creates clinically undetectable crystallization seed points with extremely high reactive surface areas, which dramatically enhance the multiple events of crystallization and dissolution (diagenetic phase transitions) that may lead to the high rates of CaOx kidney stone recurrence after SWL treatment.
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Affiliation(s)
- Lauren G. Todorov
- grid.35403.310000 0004 1936 9991Department of Geology, University of Illinois at Urbana-Champaign, Urbana, IL USA ,grid.35403.310000 0004 1936 9991Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Mayandi Sivaguru
- grid.35403.310000 0004 1936 9991Cytometry and Microscopy to Omics Facility, Roy J. Carver Biotechnology Center, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Amy E. Krambeck
- grid.66875.3a0000 0004 0459 167XDepartment of Urology, Mayo Clinic, Rochester, MN USA ,grid.16753.360000 0001 2299 3507Department of Urology, Northwestern University Feinberg School of Medicine, Chicago, IL USA
| | - Matthew S. Lee
- grid.16753.360000 0001 2299 3507Department of Urology, Northwestern University Feinberg School of Medicine, Chicago, IL USA
| | - John C. Lieske
- grid.66875.3a0000 0004 0459 167XDivision of Nephrology and Hypertension, Mayo Clinic, Rochester, MN USA ,grid.66875.3a0000 0004 0459 167XDepartment of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN USA
| | - Bruce W. Fouke
- grid.35403.310000 0004 1936 9991Department of Geology, University of Illinois at Urbana-Champaign, Urbana, IL USA ,grid.35403.310000 0004 1936 9991Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL USA ,grid.35403.310000 0004 1936 9991Department of Biomedical and Translational Sciences, Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Urbana, IL USA ,grid.35403.310000 0004 1936 9991Roy J. Carver Biotechnology Center, University of Illinois at Urbana-Champaign, Urbana, IL USA ,grid.35403.310000 0004 1936 9991Department of Evolution, Ecology and Behavior, University of Illinois at Urbana-Champaign, Urbana, IL USA
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Tzelves L, Geraghty R, Mourmouris P, Chatzikrachtis N, Karavitakis M, Somani B, Skolarikos A. Shockwave Lithotripsy Complications According to Modified Clavien-Dindo Grading System. A Systematic Review and Meta-regression Analysis in a Sample of 115 Randomized Controlled Trials. Eur Urol Focus 2022; 8:1452-1460. [PMID: 34848163 DOI: 10.1016/j.euf.2021.11.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 10/11/2021] [Accepted: 11/09/2021] [Indexed: 12/16/2022]
Abstract
CONTEXT Shockwave lithotripsy (SWL) shows clear associated benefits for urolithiasis patients. OBJECTIVE To identify and classify SWL complications according to modified Clavien-Dindo grading system while assessing the effect of different patient characteristics, stone parameters, types of lithotripters, and lithotripsy techniques. EVIDENCE ACQUISITION Literature was reviewed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement. EVIDENCE SYNTHESIS We analyzed the results of 115 randomized trials including 17827 patients, of whom 16.06%, 2.07%, 2.23%, 1.32%, 0.85%, 0.16%, and 0% suffered from Clavien I, II, III, IIIa, IIIb, IV, and V complications, respectively. In total, 18.43% of patients suffered from Clavien I-II and 2.48% from Clavien III-IV complications. In studies with >100 treated patients, Clavien I, III, and IV complication rates and need for auxiliary procedure rates were lower than in studies with smaller sample size. Electrohydraulic lithotripters led to a higher rate of Clavien IIIb and IV complications than electromagnetic lithotripters. Clavien I-II complications were increased by 14.3% in patients with multiple and complicated stones. Hematuria was increased by 8.29% in patients who underwent intravenous urography preoperatively and had longer duration of SWL. Pain occurrence was increased by 14.79% in patients with more than one stone at the time of SWL and by 3.21% in those who were managed with a piezoelectric lithotripter. CONCLUSIONS SWL should not be considered an uneventful procedure, as in 2.5% of cases an intervention or Clavien III-V complication will be observed. Low-volume centers, treatment of multiple or complex stones, a long-lasting SWL session, and electrohydraulic lithotripters are associated with higher rates of complications. PATIENT SUMMARY We analyze the occurrence of shockwave lithotripsy (SWL) complications in 17000 patients. In centers with larger caseloads, complications were less common. The type of lithotripter is associated with complications. An increased number of treated stones, complex stones, and increased SWL duration were associated with a higher incidence of pain and hematuria.
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Affiliation(s)
- Lazaros Tzelves
- 2nd Department of Urology, National and Kapodistian University of Athens, Athens, Greece
| | - Robert Geraghty
- Department of Urology, The Newcastle upon Tyne Hospitals NHS Foundation, Newcastle upon Tyne, UK
| | - Panagiotis Mourmouris
- 2nd Department of Urology, National and Kapodistian University of Athens, Athens, Greece
| | | | - Markos Karavitakis
- 2nd Department of Urology, National and Kapodistian University of Athens, Athens, Greece
| | - Bhaskar Somani
- Department of Urology, University Hospital Southampton NHS Trust, Southampton, UK
| | - Andreas Skolarikos
- 2nd Department of Urology, National and Kapodistian University of Athens, Athens, Greece.
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Bailey MR, Maxwell AD, Cao S, Ramesh S, Liu Z, Williams JC, Thiel J, Dunmire B, Colonius T, Kuznetsova E, Kreider W, Sorensen MD, Lingeman JE, Sapozhnikov OA. Improving burst wave lithotripsy effectiveness for small stones and fragments by increasing frequency: theoretical modeling and ex vivo study. J Endourol 2022; 36:996-1003. [PMID: 35229652 DOI: 10.1089/end.2021.0714] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
INTRODUCTION AND OBJECTIVE In clinical trial NCT03873259, a 2.6-mm lower pole stone was treated transcutaneously and ex vivo with 390-kHz burst wave lithotripsy (BWL) for 40 minutes and failed to break. The stone was subsequently fragmented with 650-kHz BWL after a 4-minute exposure. This study investigated how to fragment small stones and why varying BWL frequency may more effectively fragment stones to dust. METHODS A linear elastic model was used to calculate the stress created inside stones from shock wave lithotripsy (SWL) and different BWL frequencies mimicking the stone's size, shape, lamellar structure, and composition. To test model predictions about the impact of BWL frequency, matched pairs of stones (1-5 mm) were treated at 1) 390 kHz, 2) 830 kHz, and 3) 390 kHz followed by 830 kHz. The mass of fragments greater than 1 and 2 mm was measured over 10 minutes of exposure. RESULTS The linear elastic model predicts that the maximum principal stress inside a stone increases to more than 5.5 times the pressure applied by the ultrasound wave as frequency is increased, regardless of composition tested. The threshold frequency for stress amplification is proportionate to the wave speed divided by the stone diameter. Thus, smaller stones may be likely to fragment at higher frequency, but not lower frequency below a limit. Unlike with SWL, this amplification in BWL occurs consistently with spherical and irregularly shaped stones. In water tank experiments, stones smaller than the threshold size broke fastest at high frequency (p=0.0003), whereas larger stones broke equally well to sub-millimeter dust at high, low, or mixed frequency. CONCLUSIONS For small stones and fragments, increasing frequency of BWL may produce amplified stress in the stone causing the stone to break. Using the strategies outlined here, stones of all sizes may be turned to dust efficiently with BWL.
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Affiliation(s)
- Michael R Bailey
- University of Washington, Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, 1013 NE 40th St., Seattle, Washington, United States, 98105;
| | - Adam D Maxwell
- University of Washington School of Medicine, 12353, Department of Urology, 1013 NE 40th St, Seattle, Washington, United States, 98105;
| | - Shunxiang Cao
- California Institute of Technology, Dept. of Mechanical Engineering, Pasadena, California, United States;
| | - Shivani Ramesh
- University of Washington Applied Physics Lab, Center for Industrial and Medical Ultrasound, Seattle, Washington, United States;
| | - Ziyue Liu
- Indiana University School of Medicine, Biostatistics, Indianapolis, Indiana, United States;
| | - James Caldwell Williams
- Indiana Univ Sch Med, Anatomy & Cell Biology, 635 Barnhill Dr MS5035, Department of Anatomy & Cell Biology, Indianapolis, Indiana, United States, 46202-5120.,United States;
| | - Jeff Thiel
- University of Washington School of Medicine, Radiology, Seattle, Washington, United States;
| | - Barbrina Dunmire
- University of Washington, Applied Physics Lab, 1013 NE 40th St, Seattle, Washington, United States, 98105;
| | - Tim Colonius
- California Institute of Technology, Dept. of Mechanical Engineering, Pasadena, California, United States;
| | - Ekaterina Kuznetsova
- University of Washington Applied Physics Lab, Center for Industrial and Medical Ultrasound, Seattle, Washington, United States;
| | - Wayne Kreider
- University of Washington Applied Physics Lab, Center for Industrial and Medical Ultrasound, Seattle, Washington, United States;
| | - Mathew D Sorensen
- University of Washington, Department of Urology, 1959 NE Pacific Street, Box 356510, Seattle, Washington, United States, 98195;
| | - James E Lingeman
- Indiana University School of Medicine, Dept. of Urology, 1801 North Senate Blvd., Suite 220, Indianapolis, Indiana, United States, 46202;
| | - Oleg A Sapozhnikov
- University of Washington Applied Physics Lab, Center for Industrial and Medical Ultrasound, Seattle, Washington, United States.,Moscow State University, 64935, Department of Acoustics, Physics Faculty, Moskva, Moskva, Russian Federation;
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Sapozhnikov OA, Maxwell AD, Bailey MR. Maximizing mechanical stress in small urinary stones during burst wave lithotripsy. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2021; 150:4203. [PMID: 34972267 PMCID: PMC8664414 DOI: 10.1121/10.0008902] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Revised: 11/04/2021] [Accepted: 11/09/2021] [Indexed: 06/14/2023]
Abstract
Unlike shock wave lithotripsy, burst wave lithotripsy (BWL) uses tone bursts, consisting of many periods of a sinusoidal wave. In this work, an analytical theoretical approach to modeling mechanical stresses in a spherical stone was developed to assess the dependence of frequency and stone size on stress generated in the stone. The analytical model for spherical stones is compared against a finite-difference model used to calculate stress in nonspherical stones. It is shown that at low frequencies, when the wavelength is much greater than the diameter of the stone, the maximum principal stress is approximately equal to the pressure amplitude of the incident wave. With increasing frequency, when the diameter of the stone begins to exceed about half the wavelength in the surrounding liquid (the exact condition depends on the material of the stone), the maximum stress increases and can be more than six times greater than the incident pressure. These results suggest that the BWL frequency should be elevated for small stones to improve the likelihood and rate of fragmentation.
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Affiliation(s)
- Oleg A Sapozhnikov
- Physics Faculty, Moscow State University, Leninskie Gory, Moscow 119991, Russia
| | - Adam D Maxwell
- Department of Urology, University of Washington School of Medicine, Seattle, Washington 98195, USA
| | - Michael R Bailey
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, 1013 NE 40th Street, Seattle, Washington 98105, USA
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Xiang G, Ma X, Liang C, Yu H, Liao D, Sankin G, Cao S, Wang K, Zhong P. Variations of stress field and stone fracture produced at different lateral locations in a shockwave lithotripter field. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2021; 150:1013. [PMID: 34470261 PMCID: PMC8357445 DOI: 10.1121/10.0005823] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
During clinical procedures, the lithotripter shock wave (LSW) that is incident on the stone and resultant stress field is often asymmetric due to the respiratory motion of the patient. The variations of the LSW-stone interaction and associated fracture pattern were investigated by photoelastic imaging, phantom experiments, and three-dimensional fluid-solid interaction modeling at different lateral locations in a lithotripter field. In contrast to a T-shaped fracture pattern often observed in the posterior region of the disk-shaped stone under symmetric loading, the fracture pattern gradually transitioned to a tilted L-shape under asymmetric loading conditions. Moreover, the model simulations revealed the generation of surface acoustic waves (SAWs), i.e., a leaky Rayleigh wave on the anterior boundary and Scholte wave on the posterior boundary of the stone. The propagation of SAWs on the stone boundary is accompanied by a progressive transition of the LSW reflection pattern from regular to von Neumann and to weak von Neumann reflection near the glancing incidence and, concomitantly, the development and growth of a Mach stem, swirling around the stone boundary. The maximum tensile stress and stress integral were produced by SAWs on the stone boundary under asymmetric loading conditions, which drove the initiation and extension of surface cracks into the bulk of the stone that is confirmed by micro-computed tomography analysis.
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Affiliation(s)
- Gaoming Xiang
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina 27708, USA
| | - Xiaojian Ma
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina 27708, USA
| | - Cosima Liang
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina 27708, USA
| | - Hongyang Yu
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina 27708, USA
| | - Defei Liao
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina 27708, USA
| | - Georgy Sankin
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina 27708, USA
| | - Shunxiang Cao
- Department of Aerospace and Ocean Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA
| | - Kevin Wang
- Department of Aerospace and Ocean Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA
| | - Pei Zhong
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina 27708, USA
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Rassweiler J, Rieker P, Pecha R, Dressel M, Rassweiler-Seyfried MCC. In-vitro comparison of two electromagnetic shock-wave generators: low-pressure-wide focus versus high-pressure small focus - the impact on initial stone fragmentation and final stone comminution. J Endourol 2021; 36:266-272. [PMID: 34314251 DOI: 10.1089/end.2021.0416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
CONTEXT Recently developed concepts for higher efficacy ESWL with low-pressure wide focus systems resulting in finer fragmentation of the calculi. OBJECTIVE To compare two different electromagnetic shock wave sources (low-pressure wide focus (XL) versus high-pressure small focus (SL)) by sound-field measurements and in-vitro fragmentation. EVIDENCE ACQUISITION The CS-2012A XX-ES lithotripter (self-focusing electromagnetic shock-wave generator with concave spherical curved electrical coil; Xinin Lithotripter = XL) was compared to the Siemens Lithoskop (= SL) (electromagnetic generator with a flat electric coil with an acoustical lens). Different sound-field measurements were performed using a fiber-optic hydrophone. Measurements at three different power settings (XL: 8.0kV, 9.3kV and 10.3kV; SL: Level 1, 5 and 8). 10 ATS-stones and 15 BegoStones (9.3 kV, Level 3) with a frequency of 90/minute (SL) and 20/minute (XL). Number of impulses to the first crack and for complete stone comminution (residual fragments <2mm) were documented. RESULTS The median number of shock waves for the first crack in ATS-stones with the XL was 12 (10-14), with the SL 7 (6-9). Complete disintegration was accomplished after 815 (782-824) shock waves with XL, 702 (688-712) with SL. The difference was not statistically significant. The median number of shock waves to produce the first crack in BegoStones was 524 (504-542) with XL and only 151 (137-161) with SL. Numbers of shock waves for complete disintegration did not differ significantly (XL:2518 vs SL:2287). Using a wide focus with low pressure shows more homogeneous disintegration. CONCLUSION Two stone models showed significant differences regarding form and time of the initial fragmentation. Impulses for stone comminution did not differ significantly. The advantages of a low-pressure wide focus-system include minimal trauma and a homogeneous fragment size but is more time consuming. High-pressure small focus systems are clinically effective.
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Affiliation(s)
- Jens Rassweiler
- Klinikum Heilbronn, Dept. of Urology, Am Gesundbrunnen 20-24, Heilbronn, Germany, 74078.,Germany;
| | - Philip Rieker
- SLK-Kliniken, University of Heidelberg, Urology, Heilbronn, Germany;
| | - Rainer Pecha
- University of Stuttgart, 9149, Institute of Physics,, Stuttgart, Baden-Württemberg, Germany;
| | - Martin Dressel
- University of Stuttgart, 9149, Insitute of Physics, Stuttgart, Baden-Württemberg, Germany;
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Harper JD, Metzler I, Hall MK, Chen TT, Maxwell AD, Cunitz BW, Dunmire B, Thiel J, Williams JC, Bailey MR, Sorensen MD. First In-Human Burst Wave Lithotripsy for Kidney Stone Comminution: Initial Two Case Studies. J Endourol 2021; 35:506-511. [PMID: 32940089 PMCID: PMC8080914 DOI: 10.1089/end.2020.0725] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Purpose: To test the effectiveness (Participant A) and tolerability (Participant B) of urinary stone comminution in the first-in-human trial of a new technology, burst-wave lithotripsy (BWL). Materials and Methods: An investigational BWL and ultrasonic propulsion system was used to target a 7-mm kidney stone in the operating room before ureteroscopy (Participant A). The same system was used to target a 7.5 mm ureterovesical junction stone in clinic without anesthesia (Participant B). Results: For Participant A, a ureteroscope inserted after 9 minutes of BWL observed fragmentation of the stone to <2 mm fragments. Participant B tolerated the procedure without pain from BWL, required no anesthesia, and passed the stone on day 15. Conclusions: The first-in-human tests of BWL pulses were successful in that a renal stone was comminuted in <10 minutes, and BWL was also tolerated by an awake subject for a distal ureteral stone. Clinical Trial NCT03873259 and NCT02028559.
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Affiliation(s)
- Jonathan D. Harper
- Department of Urology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Ian Metzler
- Department of Urology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Michael Kennedy Hall
- Department of Emergency Medicine, University of Washington School of Medicine, Seattle, Washington, USA
| | - Tony T. Chen
- Department of Urology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Adam D. Maxwell
- Department of Urology, University of Washington School of Medicine, Seattle, Washington, USA
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, Washington, USA
| | - Bryan W. Cunitz
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, Washington, USA
| | - Barbrina Dunmire
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, Washington, USA
| | - Jeff Thiel
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, Washington, USA
| | - James C. Williams
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Michael R. Bailey
- Department of Urology, University of Washington School of Medicine, Seattle, Washington, USA
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, Washington, USA
| | - Mathew D. Sorensen
- Department of Urology, University of Washington School of Medicine, Seattle, Washington, USA
- Division of Urology, VA Puget Sound Health Care System, Seattle, Washington, USA
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11
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Rassweiler JJ, Rassweiler-Seyfried MC. Therapieverfahren – extrakorporale Stoßwellentherapie. Urolithiasis 2021. [DOI: 10.1007/978-3-662-62454-8_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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12
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Raymond SJ, Maragh J, Masic A, Williams JR. Towards an understanding of the chemo-mechanical influences on kidney stone failure via the material point method. PLoS One 2020; 15:e0240133. [PMID: 33306670 PMCID: PMC7732073 DOI: 10.1371/journal.pone.0240133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 09/20/2020] [Indexed: 11/18/2022] Open
Abstract
This paper explores the use of the meshfree computational mechanics method, the Material Point Method (MPM), to model the composition and damage of typical renal calculi, or kidney stones. Kidney stones are difficult entities to model due to their complex structure and failure behavior. Better understanding of how these stones behave when they are broken apart is a vital piece of knowledge to medical professionals whose aim is to remove these stone by breaking them within a patient’s body. While the properties of individual stones are varied, the common elements and proportions are used to generate synthetic stones that are then placed in a digital experiment to observe their failure patterns. First a more traditional engineering model of a Brazil test is used to create a tensile fracture within the center of these stones to observe the effect of stone consistency on failure behavior. Next a novel application of MPM is applied which relies on an ultrasonic wave being carried by surrounding fluid to model the ultrasonic treatment of stones commonly used by medical practitioners. This numerical modeling of Extracorporeal Shock Wave Lithotripsy (ESWL) reveals how these different stones failure in a more real-world situation and could be used to guide further research in this field for safer and more effective treatments.
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Affiliation(s)
- Samuel J. Raymond
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States of America
- Center for Computational Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States of America
- * E-mail:
| | - Janille Maragh
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States of America
| | - Admir Masic
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States of America
| | - John R. Williams
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States of America
- Center for Computational Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States of America
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13
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Karimi Galougahi K, Patel S, Shlofmitz RA, Maehara A, Kereiakes DJ, Hill JM, Stone GW, Ali ZA. Calcific Plaque Modification by Acoustic Shock Waves: Intravascular Lithotripsy in Coronary Interventions. Circ Cardiovasc Interv 2020; 14:e009354. [PMID: 32907343 DOI: 10.1161/circinterventions.120.009354] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Constituting a significant proportion of lesions treated with transcatheter interventions in the coronary arteries, moderate-to-severe calcification portends lower procedural success rates, increased periprocedural major adverse events, and unfavorable long-term clinical outcomes compared with noncalcific plaques. Adapted from the lithotripsy technology for treatment of nephrolithiasis, intravascular lithotripsy is a new technique for treatment of severely calcific lesions that uses acoustic shock waves in a balloon-based system to induce fracture in the calcium deposits to facilitate luminal gain and stent expansion. Herein, we summarize the physics and characteristics of the currently available intravascular lithotripsy system (Shockwave Medical, Santa Clara, CA), the clinical data on intravascular lithotripsy use in the coronary arteries, and future directions for adoption of the technique in percutaneous coronary intervention.
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Affiliation(s)
- Keyvan Karimi Galougahi
- Royal Prince Alfred Hospital, Sydney, Australia (K.K.G., S.P.).,Sydney Medical School, Faculty of Medicine and Health, The University of Sydney, Australia (K.K.G., S.P.).,Heart Research Institute, Sydney, Australia (K.K.G., S.P.)
| | - Sanjay Patel
- Royal Prince Alfred Hospital, Sydney, Australia (K.K.G., S.P.).,Sydney Medical School, Faculty of Medicine and Health, The University of Sydney, Australia (K.K.G., S.P.).,Heart Research Institute, Sydney, Australia (K.K.G., S.P.)
| | | | - Akiko Maehara
- NewYork-Presbyterian Hospital/Columbia University Medical Center (A.M., Z.A.A.).,Clinical Trials Center, Cardiovascular Research Foundation, New York, NY (A.M., G.W.S., Z.A.A.)
| | - Dean J Kereiakes
- Lindner Research Center, The Christ Hospital, Cincinnati, OH (D.J.K.)
| | | | - Gregg W Stone
- Clinical Trials Center, Cardiovascular Research Foundation, New York, NY (A.M., G.W.S., Z.A.A.).,Zena and Michael A. Wiener Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, NY (G.W.S.)
| | - Ziad A Ali
- Saint Francis Hospital, Roslyn, NY (R.A.S., Z.A.A.).,Clinical Trials Center, Cardiovascular Research Foundation, New York, NY (A.M., G.W.S., Z.A.A.)
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14
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Randad A, Ghanem MA, Bailey MR, Maxwell AD. Design, fabrication, and characterization of broad beam transducers for fragmenting large renal calculi with burst wave lithotripsy. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2020; 148:44. [PMID: 32752768 PMCID: PMC7340507 DOI: 10.1121/10.0001512] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 06/12/2020] [Accepted: 06/12/2020] [Indexed: 06/08/2023]
Abstract
Burst wave lithotripsy (BWL) is a technology for comminuting urinary stones. A BWL transducer's requirements of high-pressure output, limited acoustic window, specific focal depth, and frequency to produce fragments of passable size constrain focal beamwidth. However, BWL is most effective with a beam wider than the stone. To produce a broad-beam, an iterative angular spectrum approach was used to calculate a phase screen that was realized with a rapid prototyped lens. The technique did not accurately replicate a target beam profile when an axisymmetric profile was chosen. Adding asymmetric weighting functions to the target profile achieved appropriate beamwidth. Lenses were designed to create a spherically focused narrow-beam (6 mm) and a broad-beam (11 mm) with a 350-kHz transducer and 84-mm focal depth. Both lenses were used to fragment artificial stones (11 mm long) in a water bath, and fragmentation rates were compared. The linearly simulated and measured broad beamwidths that were 12 mm and 11 mm, respectively, with a 2-mm-wide null at center. The broad-beam and the narrow-beam lenses fragmented 44 ± 9% and 16 ± 4% (p = 0.007, N = 3) of a stone by weight, respectively, in the same duration at the same peak negative pressure. The method broadened the focus and improved the BWL rate of fragmentation of large stones.
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Affiliation(s)
- Akshay Randad
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, 1606 San Juan Road, Seattle, Washington 98195, USA
| | - Mohamed A Ghanem
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, 1606 San Juan Road, Seattle, Washington 98195, USA
| | - Michael R Bailey
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, 1606 San Juan Road, Seattle, Washington 98195, USA
| | - Adam D Maxwell
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, 1606 San Juan Road, Seattle, Washington 98195, USA
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15
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Sapozhnikov OA, Maxwell AD, Bailey MR. Modeling of photoelastic imaging of mechanical stresses in transparent solids mimicking kidney stones. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2020; 147:3819. [PMID: 32611160 PMCID: PMC7292679 DOI: 10.1121/10.0001386] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 05/12/2020] [Accepted: 05/18/2020] [Indexed: 05/22/2023]
Abstract
Theoretical and numerical models were developed to calculate the polariscopic integrated light intensity that forms a projection of the dynamic stress within an axisymmetric elastic object. Although the model is general, this paper addressed its application to measurements of stresses in model kidney stones from a burst wave lithotripter for stone fragmentation. The stress was calculated using linear elastic equations, and the light propagation was modeled in the instantaneous case by integrating over the volume of the stone. The numerical model was written in finite differences. The resulting images agreed well with measured images. The measured images corresponded to the maximum shear stress distribution, although other stresses were also plotted. Comparison of the modeled and observed polariscope images enabled refinement of the photoelastic constant by minimizing the error between the calculated and measured fields. These results enable quantification of the stress within the polariscope images, determination of material properties, and the modes and mechanisms of stress production within a kidney stone. Such a model may help in interpreting elastic waves in structures, such as stones, toward improving lithotripsy procedures.
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Affiliation(s)
- Oleg A Sapozhnikov
- Physics Faculty, Moscow State University, Leninskie Gory, Moscow 119991, Russia
| | - Adam D Maxwell
- Department of Urology, School of Medicine, University of Washington, Seattle, Washington 98195, USA
| | - Michael R Bailey
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, 1013 Northeast 40th Street, Seattle, Washington 98105, USA
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16
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Thomas GPL, Chapelon JY, Birer A, Inserra C, Lafon C. Confocal lens focused piezoelectric lithotripter. ULTRASONICS 2020; 103:106066. [PMID: 32028115 DOI: 10.1016/j.ultras.2020.106066] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 12/06/2019] [Accepted: 12/07/2019] [Indexed: 06/10/2023]
Abstract
This work focuses on the evaluation of a type of piezoelectric lithotripter with similar dimensions of a commercial lithotripter and composed of either 3 or 4 large lens focused piezoelectric transducers set either in a confocal coplanar C-shape or a confocal spherical shape. Each transducer is made with a 92 mm diameter 220 kHz flat piezoelectric ceramic disc and a 3D printed acoustic lens. Both confocal setups pressure field were measured with a fiber optic hydrophone, and in vitro fragmentations of 13 mm diameter and 14 mm length cylindrical model stones were done in a 2 mm mesh basket. The acoustic characterization of the three transducers confocal setup revealed a disc shaped focal volume, with a 2.2 mm width on one axis and a 9.6 mm width on the other, and a peak positive pressure of 40.9 MPa and a peak negative pressure of -16.9 MPa, while the focus of the four transducers confocal setup was similar to a traditional narrow focus high pressure lithotripter with a focus width of 2.1 mm, and a peak positive pressure of 71.9 MPa and peak negative pressure of -24.3 MPa. Both confocal setups showed in vitro fragmentation efficiency close to a commercial electroconductive lithotripter.
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Affiliation(s)
- Gilles P L Thomas
- INSERM, LabTAU, F-69003 Lyon, France; Université Lyon 1, Univ Lyon, F-69003 Lyon, France.
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17
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Maxwell AD, MacConaghy B, Bailey MR, Sapozhnikov OA. An investigation of elastic waves producing stone fracture in burst wave lithotripsy. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2020; 147:1607. [PMID: 32237849 PMCID: PMC7069764 DOI: 10.1121/10.0000847] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Burst wave lithotripsy is a method to noninvasively fragment urinary stones by short pulses of focused ultrasound. In this study, physical mechanisms of stone fracture during burst wave lithotripsy were investigated. Photoelasticity imaging was used to visualize elastic wave propagation in model stones and compare results to numerical calculations. Epoxy and glass stone models were made into rectangular, cylindrical, or irregular geometries and exposed in a degassed water bath to focused ultrasound bursts at different frequencies. A high-speed camera was used to record images of the stone during exposure through a circular polariscope backlit by a monochromatic flash source. Imaging showed the development of periodic stresses in the stone body with a pattern dependent on frequency. These patterns were identified as guided wave modes in cylinders and plates, which formed standing waves upon reflection from the distal surfaces of the stone model, producing specific locations of stress concentration in the models. Measured phase velocities compared favorably to numerically calculated modes dependent on frequency and material. Artificial stones exposed to bursts produced cracks at positions anticipated by this mechanism. These results support guided wave generation and reflection as a mechanism of stone fracture in burst wave lithotripsy.
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Affiliation(s)
- Adam D Maxwell
- Department of Urology, University of Washington School of Medicine, 1959 Northeast Pacific Street, Seattle, Washington 98195, USA
| | - Brian MacConaghy
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, Washington 98105, USA
| | - Michael R Bailey
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, Washington 98105, USA
| | - Oleg A Sapozhnikov
- Department of Acoustics, Physics Faculty, Lomonosov Moscow State University, Leninskie Gory, Moscow 119992, Russia
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18
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Cao S, Zhang Y, Liao D, Zhong P, Wang KG. Shock-Induced Damage and Dynamic Fracture in Cylindrical Bodies Submerged in Liquid. INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES 2019; 169:55-71. [PMID: 31423024 PMCID: PMC6697132 DOI: 10.1016/j.ijsolstr.2019.04.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Understanding the response of solid materials to shock loading is important for mitigating shock-induced damages and failures, as well as advancing the beneficial use of shock waves for material modifications. In this paper, we consider a representative brittle material, BegoStone, in the form of cylindrical bodies and submerged in water. We present a computational study on the causal relationship between the prescribed shock load and the resulting elastic waves and damage in the solid material. A recently developed three-dimensional computational framework, FIVER, is employed, which couples a finite volume compressible fluid solver with a finite element structural dynamics solver through the construction and solution of local, one-dimensional fluid-solid Riemann problems. The material damage and fracture are modeled and simulated using a continuum damage mechanics model and an element erosion method. The computational model is validated in the context of shock wave lithotripsy and the results are compared with experimental data. We first show that after calibrating the growth rate of microscopic damage and the threshold for macroscopic fracture, the computational framework is capable of capturing the location and shape of the shock-induced fracture observed in a laboratory experiment. Next, we introduce a new phenomenological model of shock waveform, and present a numerical parametric study on the effects of a single shock load, in which the shock waveform, magnitude, and the size of the target material are varied. In particular, we vary the waveform gradually from one that features non-monotonic decay with a tensile phase to one that exhibits monotonic decay without a tensile phase. The result suggests that when the length of the shock pulse is comparable to that of the target material, the former waveform may induce much more significant damage than the latter one, even if the two share the same magnitude, duration, and acoustic energy.
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Affiliation(s)
- S. Cao
- Department of Aerospace and Ocean Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, United States
| | - Y. Zhang
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC 90271, United States
| | - D. Liao
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC 90271, United States
| | - P. Zhong
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC 90271, United States
| | - K. G. Wang
- Department of Aerospace and Ocean Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, United States
- Corresponding author (K. G. Wang)
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19
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Randad A, Ahn J, Bailey MR, Kreider W, Harper JD, Sorensen MD, Maxwell AD. The Impact of Dust and Confinement on Fragmentation of Kidney Stones by Shockwave Lithotripsy in Tissue Phantoms. J Endourol 2019; 33:400-406. [PMID: 30595048 PMCID: PMC6533787 DOI: 10.1089/end.2018.0516] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Objective: The goal was to test whether stone composition and kidney phantom configuration affected comminution in extracorporeal shockwave lithotripsy (SWL) laboratory tests. Confinement may enhance the accumulation of dust and associated cavitation bubbles in the fluid surrounding the stone. It is known that high shockwave delivery rates in SWL are less effective because bubbles generated by one shockwave do not have sufficient time to dissolve, thereby shielding the next shockwave. Materials and Methods: Experiments were conducted with a lithotripter coupled to a water bath. The rate of comminution was measured by weighing fragments over 2 mm at 5-minute time points. First, plaster and crystal stones were broken in four phantoms: a nylon wire mesh, an open polyvinyl chloride (PVC) cup, a closed PVC cup, and an anatomical kidney model-the phantoms have decreasing fluid volumes around the stone. Second, the fluid volume in the kidney model was flushed with water at different rates (0, 7, and 86 mL/min) to remove dust. Results: The efficiency of breakage of stones decreases for the dust emitting plaster stones (percentage of breakage in 5 minutes decreased from 92% ± 2% [n = 3] in wire mesh to 19% ± 3% [n = 3] in model calix) with increasing confinement, but not for the calcite crystal stones that produced little dust (percentage of breakage changed from 87% ± 3% [n = 3] in wire mesh to 81% ± 3% [n = 3] in kidney model). Flushing the kidney phantom at the fastest rate improved comminution of smaller plaster stones by 27%. Conclusions: Phantoms restricting dispersion of dust were found to affect stone breakage in SWL and in vitro experiments should replicate kidney environments. The dust around the stone and potential cavitation may shield the stone from shockwaves and reduce efficacy of SWL. Understanding of stone composition and degree of hydronephrosis could be used to adapt patient-specific protocols.
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Affiliation(s)
- Akshay Randad
- Department of Mechanical Engineering, University of Washington, Seattle, Washington
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, Washington
| | - Justin Ahn
- Department of Urology, University of Washington School of Medicine, Seattle, Washington
| | - Michael R. Bailey
- Department of Mechanical Engineering, University of Washington, Seattle, Washington
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, Washington
- Department of Urology, University of Washington School of Medicine, Seattle, Washington
| | - Wayne Kreider
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, Washington
| | - Jonathan D. Harper
- Department of Urology, University of Washington School of Medicine, Seattle, Washington
| | - Mathew D. Sorensen
- Department of Urology, University of Washington School of Medicine, Seattle, Washington
- VA Puget Sound Health Care System, Seattle, Washington
| | - Adam D. Maxwell
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, Washington
- Department of Urology, University of Washington School of Medicine, Seattle, Washington
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Abstract
This comprehensive review updates the advances in extracorporeal lithotripsy, including improvements in external shockwave lithotripsy and innovations in ultrasound based lithotripsy, such as burst wave lithotripsy, ultrasonic propulsion, and histotripsy. Advances in endoscopic technology and training have changed the surgical approach to nephrolithiasis; however, improvements and innovations in extracorporeal lithotripsy maintain its status as an excellent option in appropriately selected patients.
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Affiliation(s)
- Tim Large
- Department of Urology, Indiana University, Methodist Hospital, 1801 Senate Boulevard, Suite 220, Indianapolis, IN 46202, USA
| | - Amy E Krambeck
- Department of Urology, Indiana University, Methodist Hospital, 1801 Senate Boulevard, Suite 220, Indianapolis, IN 46202, USA.
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21
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Fragmentation of brittle material by shock wave lithotripsy. Momentum transfer and inertia: a novel view on fragmentation mechanisms. Urolithiasis 2018; 48:137-149. [PMID: 30523389 PMCID: PMC7096366 DOI: 10.1007/s00240-018-1102-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 11/27/2018] [Indexed: 12/31/2022]
Abstract
Shock wave lithotripsy is the only non-invasive stone therapy and in clinical use since 1980. In spite of decades with millions of patients treated, the mechanism of fragmentation is still under debate. Detailed knowledge of the fragmentation process is required for improvements regarding safety and efficiency. The purpose of this paper is to gain a deeper insight into the mechanism of fragmentation by drawing attention to basic physical laws of inertia and momentum transfer. Many fragmentation experiments are based on the overall efficiency of multiple shock waves in crushing kidney stones or artificial model stones utilizing small baskets or latex pouches. Due to the high dynamic nature of the fragmentation process, in vitro and in vivo, a detailed action of a single shock wave on a particular stone target is difficult to investigate. We utilized a bifilar stone suspension, which allowed us to observe horizontal movements of model stones, their return to the initial position and orientation for repeated exposure of separate identical shocks. The method does not describe the entire fragmentation process in detail but elucidates a mechanism, which may be effective throughout shock wave lithotripsy in general. Measurements on model stones in water revealed forces in the range of 370 N, acceleration values of 100,000-200,000 m/s2 (≈ 10,000 g) and gained momentum of 3.7 × 10- 4 kg m/s we consider sufficient to break most human urinary stones. Fracture patterns of repeated identical shock waves show typical features supporting spallation (Hopkinson effect) and the mechanism of momentum transfer. Schlieren and photo-elastic images provide a visual impression of spatial stress in a transparent acrylic glass cylinder, cavitation fields outside and at the surface of the cylinder, which are compatible with the inertia model. The proposed mechanism covers coarse as well as fine fragmentation. Collapsing cavitation bubbles may have an impact on the fragmentation process but although expected, a direct action of micro-jets on sample surfaces could not be detected.
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22
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Simon JC, Bailey MR. Summary of "Biomedical Acoustics and Physical Acoustics: Shock Waves and Ultrasound for Calculus Fragmentation". PROCEEDINGS OF MEETINGS ON ACOUSTICS. ACOUSTICAL SOCIETY OF AMERICA 2018; 35:002001. [PMID: 32148645 PMCID: PMC7059322 DOI: 10.1121/2.0000948] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This paper summarizes the special session, "Shock Waves and Ultrasound for Calculus Fragmentation," that took place during the 176th Meeting of the Acoustical Society of America and 2018 Acoustics Week in Canada. The sessions were cosponsored by the Biomedical Acoustics and Physical Acoustics Technical Committees and consisted of ten talks by industry and academic researchers from institutions in the United States, France, and the Russian Federation. The sessions described basic and applied acoustic research to manage urinary stones.
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Affiliation(s)
- Julianna C Simon
- Graduate Program in Acoustics, Pennsylvania State University, Penn State 201E Applied Sciences Building, University Park, Pennsylvania, 16802
| | - Michael R Bailey
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, 1013 NE 40th St., Seattle, Washington, 98105
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23
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Fovargue D, Mitran S, Sankin G, Zhang Y, Zhong P. An experimentally-calibrated damage mechanics model for stone fracture in shock wave lithotripsy. INTERNATIONAL JOURNAL OF FRACTURE 2018; 211:203-216. [PMID: 30349151 PMCID: PMC6195326 DOI: 10.1007/s10704-018-0283-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 04/05/2018] [Indexed: 05/22/2023]
Abstract
A damage model suggested by the Tuler-Butcher concept of dynamic accumulation of microscopic defects is obtained from experimental data on microcrack formation in synthetic kidney stones. Experimental data on appearance of microcracks is extracted from micro-computed tomography images of BegoStone simulants obtained after subjecting the stone to successive pulses produced by an electromagnetic shock-wave lithotripter source. Image processing of the data is used to infer statistical distributions of crack length and width in representative transversal cross-sections of a cylindrical stone. A high-resolution finite volume computational model, capable of accurately modeling internal reflections due to local changes in material properties produced by material damage is used to simulate the accumulation of damage due to successive shocks. Comparison of statistical distributions of microcrack formation in computation and experiment allows calibration of the damage model. The model is subsequently used to compute fracture of a different aspect-ratio cylindrical stone predicting concurrent formation of two main fracture areas as observed experimentally.
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Affiliation(s)
- Daniel Fovargue
- Department of Mathematics, University of North Carolina, Chapel Hill, North Carolina, 27599-3250
| | - Sorin Mitran
- Department of Mathematics, University of North Carolina, Chapel Hill, North Carolina, 27599-3250
| | - Georgy Sankin
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina 27708
| | - Ying Zhang
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina 27708
| | - Pei Zhong
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina 27708
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Li G, Connors BA, Schaefer RB, Gallagher JJ, Evan AP. Evaluation of an experimental electrohydraulic discharge device for extracorporeal shock wave lithotripsy: Pressure field of sparker array. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2017; 142:3147. [PMID: 29195423 PMCID: PMC5696125 DOI: 10.1121/1.5010901] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 09/08/2017] [Accepted: 10/27/2017] [Indexed: 06/07/2023]
Abstract
In this paper, an extracorporeal shock wave source composed of small ellipsoidal sparker units is described. The sparker units were arranged in an array designed to produce a coherent shock wave of sufficient strength to fracture kidney stones. The objective of this paper was to measure the acoustical output of this array of 18 individual sparker units and compare this array to commercial lithotripters. Representative waveforms acquired with a fiber-optic probe hydrophone at the geometric focus of the sparker array indicated that the sparker array produces a shock wave (P+ ∼40-47 MPa, P- ∼2.5-5.0 MPa) similar to shock waves produced by a Dornier HM-3 or Dornier Compact S. The sparker array's pressure field map also appeared similar to the measurements from a HM-3 and Compact S. Compared to the HM-3, the electrohydraulic technology of the sparker array produced a more consistent SW pulse (shot-to-shot positive pressure value standard deviation of ±4.7 MPa vs ±3.3 MPa).
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Affiliation(s)
- Guangyan Li
- School of Physics, Northeast Normal University, Changchun, 130024, People's Republic of China
| | - Bret A Connors
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Medical Science Building, Room 0051, 635 Barnhill Drive, Indianapolis, Indiana 46202, USA
| | - Ray B Schaefer
- Phoenix Science and Technology, C/O John Gallagher, 12 Van Buren Circle, Goffstown, New Hampshire 03045, USA
| | - John J Gallagher
- Phoenix Science and Technology, 12 Van Buren Circle, Goffstown, New Hampshire 03045, USA
| | - Andrew P Evan
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Medical Science Building, Room 0051, 635 Barnhill Drive, Indianapolis, Indiana 46202, USA
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Wang KG. Multiphase fluid-solid coupled analysis of shock-bubble-stone interaction in shockwave lithotripsy. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2017; 33. [PMID: 27885825 DOI: 10.1002/cnm.2855] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 11/19/2016] [Accepted: 11/21/2016] [Indexed: 05/22/2023]
Abstract
A novel multiphase fluid-solid-coupled computational framework is applied to investigate the interaction of a kidney stone immersed in liquid with a lithotripsy shock wave (LSW) and a gas bubble near the stone. The main objective is to elucidate the effects of a bubble in the shock path to the elastic and fracture behaviors of the stone. The computational framework couples a finite volume 2-phase computational fluid dynamics solver with a finite element computational solid dynamics solver. The surface of the stone is represented as a dynamic embedded boundary in the computational fluid dynamics solver. The evolution of the bubble surface is captured by solving the level set equation. The interface conditions at the surfaces of the stone and the bubble are enforced through the construction and solution of local fluid-solid and 2-fluid Riemann problems. This computational framework is first verified for 3 example problems including a 1D multimaterial Riemann problem, a 3D shock-stone interaction problem, and a 3D shock-bubble interaction problem. Next, a series of shock-bubble-stone-coupled simulations are presented. This study suggests that the dynamic response of a bubble to LSW varies dramatically depending on its initial size. Bubbles with an initial radius smaller than a threshold collapse within 1 μs after the passage of LSW, whereas larger bubbles do not. For a typical LSW generated by an electrohydraulic lithotripter (pmax = 35.0MPa, pmin =- 10.1MPa), this threshold is approximately 0.12mm. Moreover, this study suggests that a noncollapsing bubble imposes a negative effect on stone fracture as it shields part of the LSW from the stone. On the other hand, a collapsing bubble may promote fracture on the proximal surface of the stone, yet hinder fracture from stone interior.
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Affiliation(s)
- Kevin G Wang
- Department of Aerospace and Ocean Engineering, Virginia Tech, Blacksburg, 24061, VA, USA
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Nikolaeva AV, Sapozhnikov OA, Bailey MR. Acoustic Radiation Force of a Quasi-Gaussian Beam on an Elastic Sphere in a Fluid. IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM : [PROCEEDINGS]. IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM 2017; 2016. [PMID: 28593033 DOI: 10.1109/ultsym.2016.7728608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Acoustic radiation force has many applications. One of the related technologies is the ability to noninvasively expel stones from the kidney. To optimize the procedure it is important to develop theoretical approaches that can provide rapid calculations of the radiation force depending in stone size and elastic properties, together with ultrasound beam diameter, intensity, and frequency. We hypothesize that the radiation force nonmonotonically depends on the ratio between the acoustic beam width and stone diameter because of coupling between the acoustic wave in the fluid and shear waves in the stone. Testing this hypothesis by considering a spherical stone and a quasi-Gaussian beam was performed in the current work. The calculation of the radiation force was conducted for elastic spheres of two types. Dependence of the magnitude of the radiation force on the beam diameter at various fixed values of stone diameters was modeled. In addition to using real material properties, speed of shear wave in the stone was varied to reveal the importance of shear waves in the stone. It was found that the radiation force reaches its maximum at the beamwidth comparable to the stone diameter; the gain in the force magnitude can reach 40% in comparison with the case of a narrow beam.
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Affiliation(s)
- A V Nikolaeva
- Department of Acoustics, Physics Faculty, Moscow State University, MSU, Moscow, Russia
| | - O A Sapozhnikov
- Department of Acoustics, Physics Faculty, Moscow State University, MSU, Moscow, Russia.,Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, CIMU APL, Seattle, USA
| | - M R Bailey
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, CIMU APL, Seattle, USA
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Xing Y, Chen TT, Simmons WN, Sankin G, Cocks FH, Lipkin ME, Preminger GM, Zhong P. Comparison of Broad vs Narrow Focal Width Lithotripter Fields. J Endourol 2017; 31:502-509. [PMID: 28340536 DOI: 10.1089/end.2016.0560] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVE To investigate the impact of lithotripter focal width on stone fragmentation. MATERIALS AND METHODS A modified reflector was used to reduce -6 dB beam size of the HM3 lithotripter, while increasing concomitantly peak pressure. Fragmentation in vitro was assessed with modified and original reflectors using BegoStone phantoms. A membrane holder was used to mimic lithotripsy in vivo, and a matrix holder was used to assess variations of fragmentation power in the focal plane of the lithotripter field. Stone fragmentation in vivo produced by the two reflectors was further compared in a swine model. RESULTS Stone fragmentation in vitro after 500 (or 2000) shocks was ∼60% (or ∼82%) vs ∼40% (or ∼75%) with original and modified reflector, respectively (p ≤ 0.0016). Fragmentation power with the modified reflector was the highest on the lithotripter axis, but dropped rapidly in the lateral direction and became insignificant at radial distances >6.0 mm. Stone fragmentation with the original reflector was lower along the lithotripter axis, but fragmentation power decayed slowly in lateral direction, with appreciable fragmentation produced at 6.0 mm. Stone fragmentation efficiency in vivo after 500 (or 2000) shocks was ∼70% (or ∼90%) vs ∼45% (or ∼80%) with original and modified reflector, respectively (p ≤ 0.04). CONCLUSIONS A lithotripter field with broad beam size yields superior stone comminution when compared with narrow beam size under comparable effective acoustic pulse energy both in vivo and in vitro. These findings may facilitate future improvements in lithotripter design to maximize comminution efficiency while minimizing tissue injury.
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Affiliation(s)
- Yifei Xing
- 1 Department of Mechanical Engineering and Materials Science, Duke University , Durham, North Carolina
| | - Tony T Chen
- 2 School of Medicine, Duke University , Durham, North Carolina
| | - Walter N Simmons
- 1 Department of Mechanical Engineering and Materials Science, Duke University , Durham, North Carolina
| | - Georgy Sankin
- 1 Department of Mechanical Engineering and Materials Science, Duke University , Durham, North Carolina
| | - Franklin H Cocks
- 1 Department of Mechanical Engineering and Materials Science, Duke University , Durham, North Carolina
| | - Michael E Lipkin
- 3 Comprehensive Kidney Stone Center/Urologic Surgery, Duke University , Durham, North Carolina
| | - Glenn M Preminger
- 3 Comprehensive Kidney Stone Center/Urologic Surgery, Duke University , Durham, North Carolina
| | - Pei Zhong
- 1 Department of Mechanical Engineering and Materials Science, Duke University , Durham, North Carolina.,3 Comprehensive Kidney Stone Center/Urologic Surgery, Duke University , Durham, North Carolina
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Simon JC, Maxwell AD, Bailey MR. Some Work on the Diagnosis and Management of Kidney Stones with Ultrasound. ACOUSTICS TODAY 2017; 13:52-59. [PMID: 30271311 PMCID: PMC6162072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Ultrasound is currently the only noninvasive technology able to completely diagnose and manage kidney stones.
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Affiliation(s)
- Julianna C Simon
- Graduate Program in Acoustics, Pennsylvania State University, 201E Applied Science Building, University Park, Pennsylvania 16802, USA
| | - Adam D Maxwell
- Center for Industrial and Medical, Ultrasound, Applied Physics Laboratory and Department of Urology, University of Washington, 1013 NE 40th Street, Seattle, Washington 98105, USA
| | - Michael R Bailey
- Center for Industrial and Medical, Ultrasound, Applied Physics Laboratory;, Department of Mechanical Engineering; and Department of Urology, University of Washington, 1013 NE 40th Street, Seattle, Washington 98105, USA
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Zhang Y, Nault I, Mitran S, Iversen ES, Zhong P. Effects of Stone Size on the Comminution Process and Efficiency in Shock Wave Lithotripsy. ULTRASOUND IN MEDICINE & BIOLOGY 2016; 42:2662-2675. [PMID: 27515177 PMCID: PMC5048526 DOI: 10.1016/j.ultrasmedbio.2016.06.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 06/03/2016] [Accepted: 06/10/2016] [Indexed: 05/11/2023]
Abstract
The effects of stone size on the process and comminution efficiency of shock wave lithotripsy (SWL) were investigated in experiments, numerical simulations and scale analysis. Cylindrical BegoStone phantoms with approximately equal height and diameter of either 4, 7 or 10 mm, in a total aggregated mass of about 1.5 g, were treated in an electromagnetic shock wave lithotripter field. The resultant stone comminution was found to correlate closely with the average peak pressure, P+(avg), incident on the stones. The P+(avg) threshold necessary to initiate stone fragmentation in water increased from 7.9 to 8.8 to 12.7 MPa, respectively, as stone size decreased from 10 to 7 to 4 mm. Similar changes in the P+(avg) threshold were observed for the 7- and 10-mm stones treated in 1,3-butanediol, in which cavitation is suppressed, suggesting that the observed size dependency is due to changes in stress distribution within stones of different size. Moreover, the slope of the correlation curve between stone comminution and ln(P¯+(avg)) in water increased with decreasing stone size, whereas the opposite trend was observed in 1,3-butanediol. The progression of stone comminution in SWL exhibited size-dependence: the 7- and 10-mm stones fragmented into progressively smaller pieces, whereas a significant portion (>30%) of the 4-mm stones reached a stalemate within the size range of 2.8 ∼ 4 mm, even after 1000 shocks. Analytical scaling considerations suggest size-dependent fragmentation behavior, a hypothesis further supported by numerical model calculations that reveal changing patterns of constructive and destructive wave interference and, thus, variations in the maximum tensile stress or stress integral produced in cylindrical and spherical stone of different sizes.
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Affiliation(s)
- Ying Zhang
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina, USA
| | - Isaac Nault
- Department of Mathematics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Sorin Mitran
- Department of Mathematics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Edwin S Iversen
- Department of Statistical Science, Duke University, Durham, North Carolina, USA
| | - Pei Zhong
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina, USA.
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Wang JC, Zhou Y. Shifting the Split Reflectors to Enhance Stone Fragmentation of Shock Wave Lithotripsy. ULTRASOUND IN MEDICINE & BIOLOGY 2016; 42:1876-1889. [PMID: 27166016 DOI: 10.1016/j.ultrasmedbio.2016.03.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 03/21/2016] [Accepted: 03/28/2016] [Indexed: 06/05/2023]
Abstract
Shock wave lithotripsy (SWL) has been used widely in urology for about three decades to treat kidney calculi. Technical development to improve performance (i.e., stone fragmentation efficiency) is continuous. Low-pressure wide-focus lithotripters have already achieved promising results. In this study, the lithotripter field and profile of lithotripter shock waves were changed simultaneously using a cost-effective and convenient design. An intact parabolic reflector was split into four pieces, and each part was moved individually. By shifting the split reflectors, the focused acoustic beams were separated. As a result, the beam width in the focal region could be increased. Both numerical models of wave propagation using a k-wave approach and hydrophone measurements showed similar pressure waveforms at the focus and the distributions along and transverse to the lithotripter axis. The increase of the shifting distance from 0 mm to 7 mm resulted in the increase of -6 dB beam width from 7.1 mm to 13.9 mm and location of tensile peak on axis moving from z = -14 mm to 1 mm. The Lithotripters at 10 kV (intact reflector) and at 12 kV with the split reflectors shifted by 5 mm were compared with each other because of their similar peak positive pressures at the focus (8.07 MPa ± 0.05 MPa vs. 7.90 MPa ± 0.11 MPa, respectively). However, there were significant differences in their positive beam width (8.7 mm vs. 10.2 mm), peak negative pressure (-6.34 MPa ± 0.04 MPa vs. -7.13 MPa ± 0.13 MPa), the maximum tensile stress (7.55 MPa vs. 8.95 MPa) and shear stress (6.1 MPa vs. 7.76 MPa) in a 10-mm diameter spherical stone and bubble collapse time (127.6 μs ± 5.4 μs vs. 212.7 μs ± 8.2 μs). As a result, stone fragmentation efficiency was enhanced about 1.8-fold (57.9% ± 4.6% vs. 32.2% ± 5.6%, p < 0.05) when shifting the split reflectors. These results suggest that this new reflector design could change the characteristics of the lithotripter field and increase stone fragmentation efficiency.
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Affiliation(s)
- Jen-Chieh Wang
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore
| | - Yufeng Zhou
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore.
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Ghorbani M, Oral O, Ekici S, Gozuacik D, Kosar A. Review on Lithotripsy and Cavitation in Urinary Stone Therapy. IEEE Rev Biomed Eng 2016; 9:264-83. [PMID: 27249837 DOI: 10.1109/rbme.2016.2573381] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Cavitation is the sudden formation of vapor bubbles or voids in liquid media and occurs after rapid changes in pressure as a consequence of mechanical forces. It is mostly an undesirable phenomenon. Although the elimination of cavitation is a major topic in the study of fluid dynamics, its destructive nature could be exploited for therapeutic applications. Ultrasonic and hydrodynamic sources are two main origins for generating cavitation. The purpose of this review is to give the reader a general idea about the formation of cavitation phenomenon and existing biomedical applications of ultrasonic and hydrodynamic cavitation. Because of the high number of the studies on ultrasound cavitation in the literature, the main focus of this review is placed on the lithotripsy techniques, which have been widely used for the treatment of urinary stones. Accordingly, cavitation phenomenon and its basic concepts are presented in Section II. The significance of the ultrasound cavitation in the urinary stone treatment is discussed in Section III in detail and hydrodynamic cavitation as an important alternative for the ultrasound cavitation is included in Section IV. Finally, side effects of using both ultrasound and hydrodynamic cavitation in biomedical applications are presented in Section V.
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Nyame YA, De S, Sarkissian C, Brown R, Kartha G, Babbar P, Monga M. Kidney Stone Models for In Vitro Lithotripsy Research: A Comprehensive Review. J Endourol 2015; 29:1106-9. [DOI: 10.1089/end.2014.0850] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Yaw A. Nyame
- Department of Urology, Glickman Urologic and Kidney Institute, Cleveland Clinic Foundation, Cleveland, Ohio
| | - Shubha De
- Department of Urology, Glickman Urologic and Kidney Institute, Cleveland Clinic Foundation, Cleveland, Ohio
| | - Carl Sarkissian
- Department of Urology, Glickman Urologic and Kidney Institute, Cleveland Clinic Foundation, Cleveland, Ohio
| | - Robert Brown
- Department of Urology, Glickman Urologic and Kidney Institute, Cleveland Clinic Foundation, Cleveland, Ohio
| | - Ganesh Kartha
- Department of Urology, Glickman Urologic and Kidney Institute, Cleveland Clinic Foundation, Cleveland, Ohio
| | - Paurush Babbar
- Department of Urology, Glickman Urologic and Kidney Institute, Cleveland Clinic Foundation, Cleveland, Ohio
| | - Manoj Monga
- Department of Urology, Glickman Urologic and Kidney Institute, Cleveland Clinic Foundation, Cleveland, Ohio
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Semins MJ, Matlaga BR. Strategies to optimize shock wave lithotripsy outcome: Patient selection and treatment parameters. World J Nephrol 2015; 4:230-234. [PMID: 25949936 PMCID: PMC4419132 DOI: 10.5527/wjn.v4.i2.230] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 12/11/2014] [Accepted: 12/19/2014] [Indexed: 02/06/2023] Open
Abstract
Shock wave lithotripsy (SWL) was introduced in 1980, modernizing the treatment of upper urinary tract stones, and quickly became the most commonly utilized technique to treat kidney stones. Over the past 5-10 years, however, use of SWL has been declining because it is not as reliably effective as more modern technology. SWL success rates vary considerably and there is abundant literature predicting outcome based on patient- and stone-specific parameters. Herein we discuss the ways to optimize SWL outcomes by reviewing proper patient selection utilizing stone characteristics and patient features. Stone size, number, location, density, composition, and patient body habitus and renal anatomy are all discussed. We also review the technical parameters during SWL that can be controlled to improve results further, including type of anesthesia, coupling, shock wave rate, focal zones, pressures, and active monitoring. Following these basic principles and selection criteria will help maximize success rate.
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de Icaza-Herrera M, Fernández F, Loske AM. Combined short and long-delay tandem shock waves to improve shock wave lithotripsy according to the Gilmore-Akulichev theory. ULTRASONICS 2015; 58:53-59. [PMID: 25553714 DOI: 10.1016/j.ultras.2014.12.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2014] [Revised: 12/11/2014] [Accepted: 12/11/2014] [Indexed: 06/04/2023]
Abstract
Extracorporeal shock wave lithotripsy is a common non-invasive treatment for urinary stones whose fragmentation is achieved mainly by acoustic cavitation and mechanical stress. A few years ago, in vitro and in vivo experimentation demonstrated that such fragmentation can be improved, without increasing tissue damage, by sending a second shock wave hundreds of microseconds after the previous wave. Later, numerical simulations revealed that if the second pulse had a longer full width at half maximum than a standard shock wave, cavitation could be enhanced significantly. On the other side, a theoretical study showed that stress inside the stone can be increased if two lithotripter shock waves hit the stone with a delay of only 20 μs. We used the Gilmore-Akulichev formulation to show that, in principle, both effects can be combined, that is, stress and cavitation could be increased using a pressure pulse with long full width at half maximum, which reaches the stone within hundreds of microseconds after two 20 μs-delayed initial shock waves. Implementing the suggested pressure profile into clinical devices could be feasible, especially with piezoelectric shock wave sources.
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Affiliation(s)
- Miguel de Icaza-Herrera
- Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Querétaro, Qro. 76230, Mexico
| | - Francisco Fernández
- Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Querétaro, Qro. 76230, Mexico
| | - Achim M Loske
- Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Querétaro, Qro. 76230, Mexico; División de Ciencias de la Salud, Universidad del Valle de México, Villas del Mesón 1000, Querétaro, Qro. 76230, Mexico.
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Wang JC, Zhou Y. Suppressing bubble shielding effect in shock wave lithotripsy by low intensity pulsed ultrasound. ULTRASONICS 2015; 55:65-74. [PMID: 25173067 DOI: 10.1016/j.ultras.2014.08.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 08/06/2014] [Accepted: 08/06/2014] [Indexed: 06/03/2023]
Abstract
Extracorporeal shock wave lithotripsy (ESWL) has been used as an effective modality to fragment kidney calculi. Because of the bubble shielding effect in the pre-focal region, the acoustic energy delivered to the focus is reduced. Low pulse repetition frequency (PRF) will be applied to dissolve these bubbles for better stone comminution efficiency. In this study, low intensity pulsed ultrasound (LIPUS) beam was aligned perpendicular to the axis of a shock wave (SW) lithotripter at its focus. The light transmission was used to evaluate the compressive wave and cavitation induced by SWs without or with a combination of LIPUS for continuous sonication. It is found that bubble shielding effect becomes dominated with the SW exposure and has a greater significant effect on cavitation than compressive wave. Using the combined wave scheme, the improvement began at the 5th pulse and gradually increased. Suppression effect on bubble shielding is independent on the trigger delay, but increases with the acoustic intensity and pulse duration of LIPUS. The peak negative and integral area of light transmission signal, which present the compressive wave and cavitation respectively, using our strategy at PRF of 1 Hz are comparable to those using SW alone at PRF of 0.1 Hz. In addition, high-speed photography confirmed the bubble activities in both free field and close to a stone surface. Bubble motion in response to the acoustic radiation force by LIPUS was found to be the major mechanism of suppressing bubble shielding effect. There is a 2.6-fold increase in stone fragmentation efficiency after 1000 SWs at PRF of 1 Hz in combination with LIPUS. In summary, combination of SWs and LIPUS is an effective way of suppressing bubble shielding effect and, subsequently, improving cavitation at the focus for a better outcome.
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Affiliation(s)
- Jen-Chieh Wang
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore
| | - Yufeng Zhou
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore.
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Abstract
PURPOSE We developed a new method of lithotripsy that uses short, broadly focused bursts of ultrasound rather than shock waves to fragment stones. We investigated the characteristics of stone comminution by burst wave lithotripsy in vitro. MATERIALS AND METHODS Artificial and natural stones (mean ± SD size 8.2 ± 3.0 mm, range 5 to 15) were treated with ultrasound bursts using a focused transducer in a water bath. Stones were exposed to bursts with focal pressure amplitude of 6.5 MPa or less at a 200 Hz burst repetition rate until completely fragmented. Ultrasound frequencies of 170, 285 and 800 kHz were applied using 3 transducers, respectively. Time to fragmentation for each stone type was recorded and fragment size distribution was measured by sieving. RESULTS Stones exposed to ultrasound bursts were fragmented at focal pressure amplitudes of 2.8 MPa or greater at 170 kHz. Fractures appeared along the stone surface, resulting in fragments that separated at the surface nearest to the transducer until the stone was disintegrated. All natural and artificial stones were fragmented at the highest focal pressure of 6.5 MPa with a mean treatment duration of 36 seconds for uric acid stones to 14.7 minutes for cystine stones. At a frequency of 170 kHz the largest artificial stone fragments were less than 4 mm. Exposure at 285 and 800 kHz produced only fragments less than 2 mm and less than 1 mm, respectively. CONCLUSIONS Stone comminution with burst wave lithotripsy is feasible as a potential noninvasive treatment method for nephrolithiasis. Adjusting the fundamental ultrasound frequency allows for stone fragment size to be controlled.
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Bryniarski P, Miernik A, Schoenthaler M, Zyczkowski M, Taborowski P, Paradysz A. Kidney stones over 2 cm in diameter-between guidelines and individual approach. World J Clin Urol 2014; 3:81-86. [DOI: 10.5410/wjcu.v3.i2.81] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 04/25/2014] [Accepted: 05/29/2014] [Indexed: 02/06/2023] Open
Abstract
The prevalence of urolithiasis has been observed to increase during last decades. Kidney stones over 2 cm in diameter are the common urologic problem. European and American Associations of Urology has published guidelines on Urolithiasis and presented the most effective tools to treat large stones. On the other hand many experienced endourologic centres choose other modalities from their armamentarium. All treatment methods are characterized by their efficacy and safety which are usually inversely proportional. It is crucial for patients and physicians to find a golden mean. Percutaneous lithotripsy is still considered treatment of choice with more than 95% efficacy. Less invasive retrograde intrarenal surgery is also less effective, but burdened with lower complication rate. Extracorporeal shockwave lithotripsy is feasible in paediatric patients with acceptable stone free rates. Open surgery (pylolithotomy and anatrophic nephrolithotomy) are almost obsolete techniques. All methods have their pros and cons. Physicians should share decisions regarding treatment modalities with patients.
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Improving the lens design and performance of a contemporary electromagnetic shock wave lithotripter. Proc Natl Acad Sci U S A 2014; 111:E1167-75. [PMID: 24639497 DOI: 10.1073/pnas.1319203111] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The efficiency of shock wave lithotripsy (SWL), a noninvasive first-line therapy for millions of nephrolithiasis patients, has not improved substantially in the past two decades, especially in regard to stone clearance. Here, we report a new acoustic lens design for a contemporary electromagnetic (EM) shock wave lithotripter, based on recently acquired knowledge of the key lithotripter field characteristics that correlate with efficient and safe SWL. The new lens design addresses concomitantly three fundamental drawbacks in EM lithotripters, namely, narrow focal width, nonidealized pulse profile, and significant misalignment in acoustic focus and cavitation activities with the target stone at high output settings. Key design features and performance of the new lens were evaluated using model calculations and experimental measurements against the original lens under comparable acoustic pulse energy (E+) of 40 mJ. The -6-dB focal width of the new lens was enhanced from 7.4 to 11 mm at this energy level, and peak pressure (41 MPa) and maximum cavitation activity were both realigned to be within 5 mm of the lithotripter focus. Stone comminution produced by the new lens was either statistically improved or similar to that of the original lens under various in vitro test conditions and was significantly improved in vivo in a swine model (89% vs. 54%, P = 0.01), and tissue injury was minimal using a clinical treatment protocol. The general principle and associated techniques described in this work can be applied to design improvement of all EM lithotripters.
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Li G, McAteer JA, Williams JC, Berwick ZC. Effect of the body wall on lithotripter shock waves. J Endourol 2013; 28:446-52. [PMID: 24308532 DOI: 10.1089/end.2013.0662] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
PURPOSE Determine the influence of passage through the body wall on the properties of lithotripter shock waves (SWs) and the characteristics of the acoustic field of an electromagnetic lithotripter. METHODS Full-thickness ex vivo segments of pig abdominal wall were secured against the acoustic window of a test tank coupled to the lithotripter. A fiber-optic probe hydrophone was used to measure SW pressures, determine shock rise time, and map the acoustic field in the focal plane. RESULTS Peak positive pressure on axis was attenuated roughly proportional to tissue thickness-approximately 6% per cm. Irregularities in the tissue path affected the symmetry of SW focusing, shifting the maximum peak positive pressure laterally by as much as ∼2 mm. Within the time resolution of the hydrophone (7-15 ns), shock rise time was unchanged, measuring ∼17-21 ns with and without tissue present. Mapping of the field showed no effect of the body wall on focal width, regardless of thickness of the body wall. CONCLUSIONS Passage through the body wall has minimal effect on the characteristics of lithotripter SWs. Other than reducing pulse amplitude and having the potential to affect the symmetry of the focused wave, the body wall has little influence on the acoustic field. These findings help to validate laboratory assessment of lithotripter acoustic field and suggest that the properties of SWs in the body are much the same as have been measured in vitro.
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Affiliation(s)
- Guangyan Li
- 1 Department of Anatomy and Cell Biology, Indiana University School of Medicine , Indianapolis, Indiana
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Saussine C. [Extracorporeal shock wave lithotripsy]. Prog Urol 2013; 23:1168-71. [PMID: 24176404 DOI: 10.1016/j.purol.2013.07.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 07/03/2013] [Indexed: 12/01/2022]
Abstract
Extracorporeal shock wave lithotripsy (ESWL) is a treatment of urinary stones with the uses of shock wave. The principle of ESWL will be exposed. The ways to localize the stones are then discussed with the mode of anesthesia. One session of ESWL will be presented in details. Contraindications, indications, prerequisit, complications and results will be briefly described.
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Affiliation(s)
- C Saussine
- Service d'urologie, nouvel hôpital civil, les hôpitaux universitaires de Strasbourg, 67091 Strasbourg cedex, France.
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Fovargue DE, Mitran S, Smith NB, Sankin GN, Simmons WN, Zhong P. Experimentally validated multiphysics computational model of focusing and shock wave formation in an electromagnetic lithotripter. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2013; 134:1598-609. [PMID: 23927200 PMCID: PMC3745489 DOI: 10.1121/1.4812881] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Revised: 03/18/2013] [Accepted: 03/26/2013] [Indexed: 05/22/2023]
Abstract
A multiphysics computational model of the focusing of an acoustic pulse and subsequent shock wave formation that occurs during extracorporeal shock wave lithotripsy is presented. In the electromagnetic lithotripter modeled in this work the focusing is achieved via a polystyrene acoustic lens. The transition of the acoustic pulse through the solid lens is modeled by the linear elasticity equations and the subsequent shock wave formation in water is modeled by the Euler equations with a Tait equation of state. Both sets of equations are solved simultaneously in subsets of a single computational domain within the BEARCLAW framework which uses a finite-volume Riemann solver approach. This model is first validated against experimental measurements with a standard (or original) lens design. The model is then used to successfully predict the effects of a lens modification in the form of an annular ring cut. A second model which includes a kidney stone simulant in the domain is also presented. Within the stone the linear elasticity equations incorporate a simple damage model.
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Affiliation(s)
- Daniel E Fovargue
- Department of Mathematics, University of North Carolina at Chapel Hill, 329 Phillips Hall, CB 3250, Chapel Hill, North Carolina 27599, USA.
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Smith NB, Zhong P. A heuristic model of stone comminution in shock wave lithotripsy. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2013; 134:1548-58. [PMID: 23927195 PMCID: PMC3745501 DOI: 10.1121/1.4812876] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Revised: 02/12/2013] [Accepted: 02/19/2013] [Indexed: 05/22/2023]
Abstract
A heuristic model is presented to describe the overall progression of stone comminution in shock wave lithotripsy (SWL), accounting for the effects of shock wave dose and the average peak pressure, P+(avg), incident on the stone during the treatment. The model is developed through adaptation of the Weibull theory for brittle fracture, incorporating threshold values in dose and P+(avg) that are required to initiate fragmentation. The model is validated against experimental data of stone comminution from two stone types (hard and soft BegoStone) obtained at various positions in lithotripter fields produced by two shock wave sources of different beam width and pulse profile both in water and in 1,3-butanediol (which suppresses cavitation). Subsequently, the model is used to assess the performance of a newly developed acoustic lens for electromagnetic lithotripters in comparison with its original counterpart both under static and simulated respiratory motion. The results have demonstrated the predictive value of this heuristic model in elucidating the physical basis for improved performance of the new lens. The model also provides a rationale for the selection of SWL treatment protocols to achieve effective stone comminution without elevating the risk of tissue injury.
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Affiliation(s)
- Nathan B Smith
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina 27708, USA
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Alibakhshi MA, Kracht JM, Cleveland RO, Filoux E, Ketterling JA. Single-shot measurements of the acoustic field of an electrohydraulic lithotripter using a hydrophone array. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2013; 133:3176-3185. [PMID: 23654419 PMCID: PMC3663848 DOI: 10.1121/1.4795801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Revised: 02/21/2013] [Accepted: 02/27/2013] [Indexed: 06/02/2023]
Abstract
Piezopolymer-based hydrophone arrays consisting of 20 elements were fabricated and tested for use in measuring the acoustic field from a shock-wave lithotripter. The arrays were fabricated from piezopolymer films and were mounted in a housing to allow submersion into water. The motivation was to use the array to determine how the shot-to-shot variability of the spark discharge in an electrohydraulic lithotripter affects the resulting focused acoustic field. It was found that the dominant effect of shot-to-shot variability was to laterally shift the location of the focus by up to 5 mm from the nominal acoustic axis of the lithotripter. The effect was more pronounced when the spark discharge was initiated with higher voltages. The lateral beamwidth of individual, instantaneous shock waves were observed to range from 1.5 mm to 24 mm. Due to the spatial variation of the acoustic field, the average of instantaneous beamwidths were observed to be 1 to 2 mm narrower than beamwidths determined from traditional single-point measurements that average the pressure measured at each location before computing beamwidth.
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Affiliation(s)
- Mohammad A Alibakhshi
- Department of Mechanical Engineering, Boston University, 110 Cummington Street, Boston, Massachusetts 02215, USA
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Rosa M, Usai P, Miano R, Kim FJ, Agrò EF, Bove P, Micali S. Recent finding and new technologies in nephrolitiasis: a review of the recent literature. BMC Urol 2013; 13:10. [PMID: 23413950 PMCID: PMC3599704 DOI: 10.1186/1471-2490-13-10] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 02/06/2013] [Indexed: 11/24/2022] Open
Abstract
This review summarizes recent literature on advances regarding renal and ureteral calculi, with particular focus in areas of recent advances in the overall field of urolithiasis. Clinical management in everyday practice requires a complete understanding of the issues regarding metabolic evaluation and subgrouping of stone-forming patients, diagnostic procedures, effective treatment regime in acute stone colic, medical expulsive therapy, and active stone removal. In this review we focus on new perspectives in managing nephrolitihiasis and discuss recentadvances, including medical expulsive therapy, new technologies, and refinements of classical therapy such as shock wave lithotripsy, give a fundamental modification of nephrolithiasis management. Overall, this field appears to be the most promising, capable of new developments in ureterorenoscopy and percutaneous approaches. Further improvements are expected from robotic-assisted procedures, such as flexible robotics in ureterorenoscopy.
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Affiliation(s)
- Marco Rosa
- Department of Urology, University of Modena, Via del Pozzo, 71-41124, Modena, Italy
| | - Paolo Usai
- Department of Urology, University of Cagliari, Via Aurelio Nicolodi, 1 09123, Cagliari, Italy
| | - Roberto Miano
- Department of Urology, University “Tor Vergata”, Rome, Italy
| | - Fernando J Kim
- Department of Urology, Denver Health Care Center, 777 Bannock Street, Denver, CO, 80204-4597, USA
| | | | - Pierluigi Bove
- Department of Urology, University “Tor Vergata”, Rome, Italy
| | - Salvatore Micali
- Department of Urology, Denver Health Care Center, 777 Bannock Street, Denver, CO, 80204-4597, USA
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Pishchalnikov YA, McAteer JA, Williams JC, Connors BA, Handa RK, Lingeman JE, Evan AP. Evaluation of the LithoGold LG-380 lithotripter: in vitro acoustic characterization and assessment of renal injury in the pig model. J Endourol 2013; 27:631-9. [PMID: 23228113 DOI: 10.1089/end.2012.0611] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
PURPOSE Conduct a laboratory evaluation of a novel low-pressure, broad focal zone electrohydraulic lithotripter (TRT LG-380). METHODS Mapping of the acoustic field of the LG-380, along with a Dornier HM3, a Storz Modulith SLX, and a XiXin CS2012 (XX-ES) lithotripter was performed using a fiberoptic hydrophone. A pig model was used to assess renal response to 3000 shockwaves (SW) administered by a multistep power ramping protocol at 60 SW/min, and when animals were treated at the maximum power setting at 120 SW/min. Injury to the kidney was assessed by quantitation of lesion size and routine measures of renal function. RESULTS SW amplitudes for the LG-380 ranged from (P(+)/P(-)) 7/-1.8 MPa at PL-1 to 21/-4 MPa at PL-11 while focal width measured ~20 mm, wider than the HM3 (8 mm), SLX (2.6 mm), or XX-ES (18 mm). For the LG-380, there was gradual narrowing of the focal width to ~10 mm after 5000 SWs, but this had negligible effect on breakage of model stones, because stones positioned at the periphery of the focal volume (10 mm off-axis) broke nearly as well as stones at the target point. Kidney injury measured less than 0.1% FRV (functional renal volume) for pigs treated using a gradual power ramping protocol at 60 SW/min and when SWs were delivered at maximum power at 120 SW/min. CONCLUSIONS The LG-380 exhibits the acoustic characteristics of a low-pressure, wide focal zone lithotripter and has the broadest focal width of any lithotripter yet reported. Although there was a gradual narrowing of focal width as the electrode aged, the efficiency of stone breakage was not affected. Because injury to the kidney was minimal when treatment followed either the recommended slow SW-rate multistep ramping protocol or when all SWs were delivered at fast SW-rate using maximum power, this appears to be a relatively safe lithotripter.
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Affiliation(s)
- Yuri A Pishchalnikov
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, 635 Barnhill Dr., Indianapolis, IN 46202-5120, USA
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Duryea AP, Roberts WW, Cain CA, Hall TL. Controlled cavitation to augment SWL stone comminution: mechanistic insights in vitro. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2013; 60:301-309. [PMID: 23357904 PMCID: PMC3777638 DOI: 10.1109/tuffc.2013.2566] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Stone comminution in shock wave lithotripsy (SWL) has been documented to result from mechanical stresses conferred directly to the stone, as well as the activity of cavitational microbubbles. Studies have demonstrated that the presence of this cavitation activity is crucial for stone subdivision; however, its exact role in the comminution process remains somewhat weakly defined, in part because it is difficult to isolate the cavitational component from the shock waves themselves. In this study, we further explored the importance of cavitation in SWL stone comminution through the use of histotripsy ultrasound therapy. Histotripsy was used to target model stones designed to mimic the mid-range tensile fracture strength of naturally occurring cystine calculi with controlled cavitation at strategic time points in the SWL comminution process. All SWL was applied at a peak positive pressure (p+) of 34 MPa and a peak negative pressure (p-) of 8 MPa; a shock rate of 1 Hz was used. Histotripsy pulses had a p- of 33 MPa and were applied at a pulse repetition frequency (PRF) of 100 Hz. Ten model stones were sonicated in vitro with each of five different treatment schemes: A) 10 min of SWL (600 shocks) with 0.7 s of histotripsy interleaved between successive shocks (totaling to 42 000 pulses); B) 10 min of SWL (600 shocks) followed by 10 min of histotripsy applied in 0.7-s bursts (1 burst per second, totaling to 42 000 pulses); C) 10 min of histotripsy applied in 0.7-s bursts (42 000 pulses) followed by 10 min of SWL (600 shocks); D) 10 min of SWL only (600 shocks); E) 10 min of histotripsy only, applied in 0.7-s bursts (42 000 pulses). Following sonication, debris was collected and sieved through 8-, 6-, 4-, and 2-mm filters. It was found that scheme D, SWL only, generated a broad range of fragment sizes, with an average of 14.9 ± 24.1% of the original stone mass remaining > 8 mm. Scheme E, histotripsy only, eroded the surface of stones to tiny particulate debris that was small enough to pass through the finest filter used in this study (<2 mm), leaving behind a single primary stone piece (>8 mm) with mass 85.1 ± 1.6% of the original following truncated sonication. The combination of SWL and histotripsy (schemes A, B, and C) resulted in a shift in the size distribution toward smaller fragments and complete elimination of debris > 8 mm. When histotripsy-controlled cavitation was applied following SWL (B), the increase in exposed stone surface area afforded by shock wave stone subdivision led to enhanced cavitation erosion. When histotripsy-controlled cavitation was applied before SWL (C), it is likely that stone surface defects induced by cavitation erosion provided sites for crack nucleation and accelerated shock wave stone subdivision. Both of these effects are likely at play in the interleaved therapy (A), although shielding of shock waves by remnant histotripsy microbubble nuclei may have limited the efficacy of this scheme. Nevertheless, these results demonstrate the important role played by cavitation in the stone comminution process, and suggest that the application of controlled cavitation at strategic time points can provide an adjunct to traditional SWL therapy.
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Affiliation(s)
- Alexander P. Duryea
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - William W. Roberts
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
- Department of Urology, University of Michigan, Ann Arbor, MI, USA
| | - Charles A. Cain
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Timothy L. Hall
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
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Abstract
Previous studies have demonstrated that stone comminution decreases with increased pulse repetition frequency as a result of bubble proliferation in the cavitation field of a shock wave lithotripter (Pishchalnikov et al 2011 J. Acoust. Soc. Am. 130 EL87-93). If cavitation nuclei remain in the propagation path of successive lithotripter pulses, especially in the acoustic coupling cushion of the shock wave source, they will consume part of the incident wave energy, leading to reduced tensile pressure in the focal region and thus lower stone comminution efficiency. We introduce a method to remove cavitation nuclei from the coupling cushion between successive shock exposures using a jet of degassed water. As a result, pre-focal bubble nuclei lifetime quantified by B-mode ultrasound imaging was reduced from 7 to 0.3 s by a jet with an exit velocity of 62 cm s(-1). Stone fragmentation (percent mass <2 mm) after 250 shocks delivered at 1 Hz was enhanced from 22 ± 6% to 33 ± 5% (p = 0.007) in water without interposing tissue mimicking materials. Stone fragmentation after 500 shocks delivered at 2 Hz was increased from 18 ± 6% to 28 ± 8% (p = 0.04) with an interposing tissue phantom of 8 cm thick. These results demonstrate the critical influence of cavitation bubbles in the coupling cushion on stone comminution and suggest a potential strategy to improve the efficacy of contemporary shock wave lithotripters.
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Affiliation(s)
- Jaclyn Lautz
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC 27708, USA
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Bhojani N, Lingeman JE. Shockwave lithotripsy-new concepts and optimizing treatment parameters. Urol Clin North Am 2012. [PMID: 23177635 DOI: 10.1016/j.ucl.2012.09.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The treatment of kidney stone disease has changed dramatically over the past 30 years. This change is due in large part to the arrival of extracorporeal shock wave lithotripsy (ESWL). ESWL along with the advances in ureteroscopic and percutaneous techniques has led to the virtual extinction of open surgical treatments for kidney stone disease. Much research has gone into understanding how ESWL can be made more efficient and safe. This article discusses the parameters that can be used to optimize ESWL outcomes as well as the new concepts that are affecting the efficacy and efficiency of ESWL.
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Affiliation(s)
- Naeem Bhojani
- Department of Urology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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Li G, Williams JC, Pishchalnikov YA, Liu Z, McAteer JA. Size and location of defects at the coupling interface affect lithotripter performance. BJU Int 2012; 110:E871-7. [PMID: 22938566 DOI: 10.1111/j.1464-410x.2012.11382.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
UNLABELLED Study Type--Therapy (case series) Level of Evidence 4. What's known on the subject? and What does the study add? In shock wave lithotripsy air pockets tend to get caught between the therapy head of the lithotripter and the skin of the patient. Defects at the coupling interface hinder the transmission of shock wave energy into the body, reducing the effectiveness of treatment. This in vitro study shows that ineffective coupling not only blocks the transmission of acoustic pulses but also alters the properties of shock waves involved in the mechanisms of stone breakage, with the effect dependent on the size and location of defects at the coupling interface. OBJECTIVE • To determine how the size and location of coupling defects caught between the therapy head of a lithotripter and the skin of a surrogate patient (i.e. the acoustic window of a test chamber) affect the features of shock waves responsible for stone breakage. MATERIALS AND METHODS • Model defects were placed in the coupling gel between the therapy head of a Dornier Compact-S electromagnetic lithotripter (Dornier MedTech, Kennesaw, GA, USA) and the Mylar (biaxially oriented polyethylene terephthalate) (DuPont Teijin Films, Chester, VA, USA) window of a water-filled coupling test system. • A fibre-optic probe hydrophone was used to measure acoustic pressures and map the lateral dimensions of the focal zone of the lithotripter. • The effect of coupling conditions on stone breakage was assessed using gypsum model stones. RESULTS • Stone breakage decreased in proportion to the area of the coupling defect; a centrally located defect blocking only 18% of the transmission area reduced stone breakage by an average of almost 30%. • The effect on stone breakage was greater for defects located on-axis and decreased as the defect was moved laterally; an 18% defect located near the periphery of the coupling window (2.0 cm off-axis) reduced stone breakage by only ~15% compared to when coupling was completely unobstructed. • Defects centred within the coupling window acted to narrow the focal width of the lithotripter; an 8.2% defect reduced the focal width ~30% compared to no obstruction (4.4 mm vs 6.5 mm). • Coupling defects located slightly off centre disrupted the symmetry of the acoustic field; an 18% defect positioned 1.0 cm off-axis shifted the focus of maximum positive pressure ~1.0 mm laterally. • Defects on and off-axis imposed a significant reduction in the energy density of shock waves across the focal zone. CONCLUSIONS • In addition to blocking the transmission of shock-wave energy, coupling defects also disrupt the properties of shock waves that play a role in stone breakage, including the focal width of the lithotripter and the symmetry of the acoustic field • The effect is dependent on the size and location of defects, with defects near the centre of the coupling window having the greatest effect. • These data emphasize the importance of eliminating air pockets from the coupling interface, particularly defects located near the centre of the coupling window.
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Affiliation(s)
- Guangyan Li
- Departments of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
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Bach C, Karaolides T, Buchholz N. Extracorporeal shock wave lithotripsy: What is new? Arab J Urol 2012; 10:289-95. [PMID: 26558039 PMCID: PMC4442960 DOI: 10.1016/j.aju.2012.04.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Revised: 04/01/2012] [Accepted: 04/02/2012] [Indexed: 10/28/2022] Open
Abstract
OBJECTIVES Thirty years after its introduction, extracorporeal shockwave lithotripsy (ESWL) is still first-line treatment for more than half of all urinary tract stones, but machines and treatment strategies have significantly developed over time. In this review, we summarise the latest knowledge about the clinically important aspects of ESWL. METHODS We searched PubMed to identify relevant reports and the latest European Association of Urology guidelines, and standard urological textbooks were consulted. RESULTS New technical developments include: Twin-head and tandem-pulse shock-wave generators; wide-focus, low-pressure systems; optimised coupling; and automated location and acoustic tracking systems. Indications have been refined, making possible the identification of patients in whom ESWL treatment is likely to fail. By lowering the shock-wave rate, improving coupling, applying abdominal compression, power 'ramping' and postoperative medical expulsion therapy, treatment protocols have been optimised. CONCLUSIONS Promising new technical developments are under development, with the potential to increase the stone-free rate after ESWL. For optimal results, the refined indications need to be respected and optimised treatment protocols should be applied.
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Affiliation(s)
- Christian Bach
- Endourology and Stone Services, Barts and The London NHS Trust, United Kingdom
| | | | - Noor Buchholz
- Endourology and Stone Services, Barts and The London NHS Trust, United Kingdom
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