Why Stones Break Better at Slow Shockwave Rates Than at Fast Rates: <i>In Vitro</i> Study with a Research Electrohydraulic Lithotripter

Pishchalnikov, Yuri A.; McAteer, James A.; Williams, James C.; Pishchalnikova, Irina V.; VonDerHaar, R. Jason

doi:10.1089/end.2006.20.537

Cited by 97 publications

(88 citation statements)

References 25 publications

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“…In previous studies, we have shown that shielding effect reduces the cavitation on the surface of the stone, 2 which is a significant factor in producing fine fragments by means of surface erosion and weakening the structure of stone that makes the further fragmentation to smaller pieces more probable during subsequent SWs. [13][14][15] As a result, by removing prefocal cavitation from the propagation path and reducing the shielding effect, it was expected to see lower amount of large fragments when ABC was applied.…”

Section: Discussionmentioning

confidence: 99%

“…A strong rate dependence in the efficacy of stone comminution for shockwave lithotripsy (SWL) has been shown by many in vitro, [1][2][3][4] in vivo, 5 and human studies. [6][7][8] It is hypothesized that a major component of this effect is due to the presence of cavitation bubbles persisting from shockwave (SW) to SW that shields or attenuates the amplitude of subsequent lithotripter SWs.…”

Section: Introductionmentioning

confidence: 99%

“…However, the residual micron-sized bubbles following a cavitation cloud collapse have a longer lifespan on the order of 1 second and thus a large fraction would be expected to persist between subsequent SWs, particularly at higher firing rates. 2,[16][17][18] On subsequent pulses, these nuclei absorb energy from the negative pressure phase of the lithotripter waveform, reducing cavitation on the surface of the stone, which in turn reduces the efficacy of stone comminution. 2 In our previous studies, low-amplitude acoustic bursts were used with in vitro models to actively remove residual cavitation bubbles through forced coalescence.…”

Section: Introductionmentioning

confidence: 99%

“…2,[16][17][18] On subsequent pulses, these nuclei absorb energy from the negative pressure phase of the lithotripter waveform, reducing cavitation on the surface of the stone, which in turn reduces the efficacy of stone comminution. 2 In our previous studies, low-amplitude acoustic bursts were used with in vitro models to actively remove residual cavitation bubbles through forced coalescence. 1,19,20 Significant improvement was demonstrated in the comminution efficacy of SWL at higher rates (120 and 60 SW/minute).…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Enhanced High-Rate Shockwave Lithotripsy Stone Comminution in an In Vivo Porcine Model Using Acoustic Bubble Coalescence

Tamaddoni

Roberts

Duryea³

et al. 2016

Journal of Endourology

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Cavitation plays a significant role in the efficacy of stone comminution during shockwave lithotripsy (SWL). Although cavitation on the surface of urinary stones helps to improve fragmentation, cavitation bubbles along the propagation path may shield or block subsequent shockwaves (SWs) and potentially induce collateral tissue damage. Previous in vitro work has shown that applying low-amplitude acoustic waves after each SW can force bubbles to consolidate and enhance SWL efficacy. In this study, the feasibility of applying acoustic bubble coalescence (ABC) in vivo was tested. Model stones were percutaneously implanted and treated with 2500 lithotripsy SWs at 120 SW/minute with or without ABC. Comparing the results of stone comminution, a significant improvement was observed in the stone fragmentation process when ABC was used. Without ABC, only 25% of the mass of the stone was fragmented to particles <2 mm in size. With ABC, 75% of the mass was fragmented to particles <2 mm in size. These results suggest that ABC can reduce the shielding effect of residual bubble nuclei, resulting in a more efficient SWL treatment.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Enhanced High-Rate Shockwave Lithotripsy Stone Comminution in an In Vivo Porcine Model Using Acoustic Bubble Coalescence

Tamaddoni

Roberts

Duryea³

et al. 2016

Journal of Endourology

View full text Add to dashboard Cite

show abstract

“…Extensive testing, both in vitro [1][2][3][4][5] and in vivo, 6 has demonstrated that the efficiency of stone fragmentation decreases by increasing SW rate. This work is corroborated by numerous human studies, [7][8][9][10][11][12][13] in which it was observed that slow rates (60-90 SW/min) yield more successful outcomes than high rates (120 SW/min).…”

Section: Introductionmentioning

confidence: 99%

Acoustic Bubble Removal to Enhance SWL Efficacy at High Shock Rate: An In Vitro Study

Duryea

Roberts

Cain

et al. 2014

Journal of Endourology

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Rate-dependent efficacy has been extensively documented in shock wave lithotripsy (SWL) stone comminution, with shock waves (SWs) delivered at a low rate producing more efficient fragmentation in comparison to those delivered at high rates. Cavitation is postulated to be the primary source underlying this rate phenomenon. Residual bubble nuclei that persist along the axis of SW propagation can drastically attenuate the waveform's negative phase, decreasing the energy which is ultimately delivered to the stone and compromising comminution. The effect is more pronounced at high rates, as residual nuclei have less time to passively dissolve between successive shocks. In this study, we investigate a means of actively removing such nuclei from the field using a low-amplitude acoustic pulse designed to stimulate their aggregation and subsequent coalescence. To test the efficacy of this bubble removal scheme, model kidney stones were treated in vitro using a research electrohydraulic lithotripter. SWL was applied at rates of 120, 60, or 30 SW/min with or without the incorporation of bubble removal pulses. Optical images displaying the extent of cavitation in the vicinity of the stone were also collected for each treatment. Results show that bubble removal pulses drastically enhance the efficacy of stone comminution at the higher rates tested (120 and 60 SW/min), while optical images show a corresponding reduction in bubble excitation along the SW axis when bubble removal pulses are incorporated. At the lower rate of 30 SW/min, no difference in stone comminution or bubble excitation was detected with the addition of bubble removal pulses, suggesting that remnant nuclei had sufficient time for more complete dissolution. These results corroborate previous work regarding the role of cavitation in rate-dependent SWL efficacy, and suggest that the effect can be mitigated via appropriate control of the cavitation environment surrounding the stone.

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Kidney and Ureter Calculi

et al. 2019

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Why Stones Break Better at Slow Shockwave Rates Than at Fast Rates: In Vitro Study with a Research Electrohydraulic Lithotripter

Cited by 97 publications

References 25 publications

Enhanced High-Rate Shockwave Lithotripsy Stone Comminution in an In Vivo Porcine Model Using Acoustic Bubble Coalescence

Enhanced High-Rate Shockwave Lithotripsy Stone Comminution in an In Vivo Porcine Model Using Acoustic Bubble Coalescence

Acoustic Bubble Removal to Enhance SWL Efficacy at High Shock Rate: An In Vitro Study

Kidney and Ureter Calculi

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