Shock Wave Lithotripters With Broad Focus Result in Greater Stress in Human Kidney Stones: Numerical Simulation

2008 ◽  
Author(s):  
Haibiao Luo ◽  
Robin O. Cleveland ◽  
James C. Williams
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Kidney Stones ◽  
Three Dimensional ◽  
Kidney Tissue ◽  
Human Kidney ◽  
Micro Computed Tomography ◽  
Displacement Fields ◽  
Computed Tomography Images ◽  
Shock Wave Lithotripters

Shock wave lithotripsy (SWL) has been used to treat kidney stones for decades. However, there is growing recognition that shock waves induces trauma to kidney tissue [1, 2]. The poor understanding of stone comminution mechanisms means that the design of new lithotripters is principally a practice of empiricism [3]. A mechanistic understanding of stone comminution would provide a criterion to develop new lithotripsy systems. In this work, a three-dimensional finite-difference time-domain (FDTD) solution to the linear elastic equations was employed [4] to investigate the stress and displacement fields of kidney stones subject to lithotripsy shock waves. The kidney stone models were obtained from micro-computed tomography images (resolution of 20 μm) and have diameters from 2 mm to 5 mm.

scholarly journals Application of subject-specific adaptive mechanical loading for bone healing in a mouse tail vertebral defect

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Angad Malhotra ◽  
Matthias Walle ◽  
Graeme R. Paul ◽  
Gisela A. Kuhn ◽  
Ralph Müller
Keyword(s):  
Mechanical Loading ◽  
Bone Defect ◽  
Bone Healing ◽  
Three Dimensional ◽  
Patient Specific ◽  
Dependent Manner ◽  
Micro Computed Tomography ◽  
Computed Tomography Images ◽  
Bone Defect Healing ◽  
Subject Specific

AbstractMethods to repair bone defects arising from trauma, resection, or disease, continue to be sought after. Cyclic mechanical loading is well established to influence bone (re)modelling activity, in which bone formation and resorption are correlated to micro-scale strain. Based on this, the application of mechanical stimulation across a bone defect could improve healing. However, if ignoring the mechanical integrity of defected bone, loading regimes have a high potential to either cause damage or be ineffective. This study explores real-time finite element (rtFE) methods that use three-dimensional structural analyses from micro-computed tomography images to estimate effective peak cyclic loads in a subject-specific and time-dependent manner. It demonstrates the concept in a cyclically loaded mouse caudal vertebral bone defect model. Using rtFE analysis combined with adaptive mechanical loading, mouse bone healing was significantly improved over non-loaded controls, with no incidence of vertebral fractures. Such rtFE-driven adaptive loading regimes demonstrated here could be relevant to clinical bone defect healing scenarios, where mechanical loading can become patient-specific and more efficacious. This is achieved by accounting for initial bone defect conditions and spatio-temporal healing, both being factors that are always unique to the patient.

Induction of Microdamage Through Application of Acoustic Energy to Cortical Bone

2004 ◽  
Author(s):  
Andrea E. Tami ◽  
Melissa L. Knothe Tate ◽  
Jamie R. Streem ◽  
Ryan S. Comisford ◽  
Jared M. O’Leary ◽  
...  
Keyword(s):  
Shock Wave ◽  
Confocal Microscopy ◽  
Shock Waves ◽  
Bone Turnover ◽  
Cortical Bone ◽  
Kidney Stones ◽  
Acoustic Energy ◽  
Wave Number ◽  
Extracorporeal Shock Waves ◽  
Naturally Occurring

Extracorporeal shock waves (ESW) are used routinely to break up kidney stones. Recently ESW has been implemented in the orthopaedic arena to treat heel spurs, although the mechanism underlying this therapeutic effect is not known. Acoustic energy has been shown to increase transport in bone. Furthermore, naturally occurring microdamage in bone has been implicated as a trigger for the onset of remodeling. We hypothesize that controlled application of ESW to bone tissue increases transport and stimulates bone turnover through production of low-level microdamage. The goal of this study was to identify the bandwidth and the application regime of acoustic energy to produce such damage. Transverse sections of sheep metacarpi (1 cm) were subjected to acoustic loading regimes of varying shock wave number and intensity. Thereafter, the blocks were bulk-stained with procion dye, embedded in PMMA, and sectioned into 100 mm slices for confocal microscopy and analysis. The blocks loaded with the highest energy regimes showed marked diffuse microdamage and microcracks, usually at sites of discontinuity along the periosteal edge. These results provide a first step in testing our hypothesis and ultimately may provide a basis for the exploitation of ESW to prevent osteopenia and/or osteoporosis.

Innovative Piezoelectric Extracorporeal Lithotripter

2008 ◽  
pp. 745-753
Author(s):  
Achim M. Loske ◽  
Francisco Fernández ◽  
Gilberto Fernández
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Kidney Stones ◽  
Open Surgery ◽  
Shock Wave Lithotripsy ◽  
Renal Tissue ◽  
The Body ◽  
Extracorporeal Shock Wave ◽  
Tissue Trauma ◽  
Salivary Gland Stones

Before 1980, the majority of patients with urolithiasis and nephrolithiasis needed surgery (Kerbl, Rehman, Landman, Lee, Sundaram, & Clayman, 2002; Soucie et al., 1994). Fortunately, percutaneous nephrolithotomy, ureteroscopic intrarenal surgery, laparoscopic surgery, and extracorporeal shock wave lithotripsy (SWL) now allow almost any calculus to be removed without open surgery. SWL refers to the use of high intensity pressure pulses, generated outside the body, to break up kidney stones (Chaussy, Brendel, & Schmiedt, 1980; Loske, 2007). It has become the standard treatment for the majority of patients and an alternative in the management of gallbladder stones, pancreatic concrements, and salivary gland stones. Even though initial studies concluded that shock waves had no damaging effect on renal tissue, later several authors reported that shock waves may cause tissue trauma (Evan, Willis, Connors, McAteer, & Lingeman, 1991; Evan, Willis, & Lingeman, 2003 Willis et al., 1999). Fortunately, techniques and devices are still evolving and improvements to increase stone fragmentation efficiency and reduce tissue trauma are being constantly sought.

scholarly journals Hydrodynamic and Thermodynamic Nonequilibrium Effects around Shock Waves: Based on a Discrete Boltzmann Method

Entropy ◽  
2020 ◽  
Vol 22 (12) ◽  
pp. 1397
Author(s):  
Chuandong Lin ◽  
Xianli Su ◽  
Yudong Zhang
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Local Equilibrium ◽  
Nonequilibrium Statistical Mechanics ◽  
Three Dimensional ◽  
Distribution Functions ◽  
Velocity Distribution Functions ◽  
Nonequilibrium Effects ◽  
Boltzmann Method ◽  
Boltzmann Model

A shock wave that is characterized by sharp physical gradients always draws the medium out of equilibrium. In this work, both hydrodynamic and thermodynamic nonequilibrium effects around the shock wave are investigated using a discrete Boltzmann model. Via Chapman–Enskog analysis, the local equilibrium and nonequilibrium velocity distribution functions in one-, two-, and three-dimensional velocity space are recovered across the shock wave. Besides, the absolute and relative deviation degrees are defined in order to describe the departure of the fluid system from the equilibrium state. The local and global nonequilibrium effects, nonorganized energy, and nonorganized energy flux are also investigated. Moreover, the impacts of the relaxation frequency, Mach number, thermal conductivity, viscosity, and the specific heat ratio on the nonequilibrium behaviours around shock waves are studied. This work is helpful for a deeper understanding of the fine structures of shock wave and nonequilibrium statistical mechanics.

scholarly journals Underwater Shock Waves to Medicine

2000 ◽  
Author(s):  
Kazuyoshi Takayama
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Kidney Stones ◽  
Research Topics ◽  
Bladder Stones ◽  
Wave Research ◽  
Underwater Shock

Abstract Application of underwater shock waves to medicine is one of the most interesting research topics in shock wave research. The facility of disintegrating bladder stones by using spark generated shock waves was invented by Yutkin in 1950. Later his method was combined with an endoscope to disintegrate kidney stones.

Elastic waves in human kidney stones: Shear dominates spall in shock wave lithotripsy

2008 ◽  
Vol 123 (5) ◽  
pp. 3368-3368
Author(s):  
Robin O. Cleveland ◽  
Haibiao Luo ◽  
James C. Williams
Keyword(s):  
Shock Wave ◽  
Kidney Stones ◽  
Elastic Waves ◽  
Shock Wave Lithotripsy ◽  
Human Kidney

The Mechanism of Three-Dimension Steady Shock Wave Interaction

2018 ◽  
Author(s):  
Chun Wang ◽  
Ruixin Yang ◽  
Zonglin Jiang
Keyword(s):  
Boundary Layer ◽  
Shock Wave ◽  
Shock Waves ◽  
Three Dimensional ◽  
Wave Interaction ◽  
Local Heat ◽  
Three Dimension ◽  
Complex Flow ◽  
Shock Wave Interaction ◽  
Steady Shock

The problem of three-dimensional steady shock wave interaction is a key issue for supersonic and hypersonic corner flow. Due to the complexity of shock configurations, there is no analytical theory to such problem and the mechanism of three-dimensional shock waves and boundary layer interaction has not been clearly known. In this paper, an analytical approach to the problem of three-dimensional steady shock wave interaction was exhibited to analytically interpret the mechanism of three-dimensional interaction of two oblique planar shock waves. The results showed that the problem of three-dimensional steady shock wave interaction could be transformed to that of two moving shock wave interaction in two-dimensional plane, and there are various interaction configurations such as regular interaction, Mach interaction and weak interaction. The mechanism of three-dimensional shock wave interaction is helpful to understand the complex flow mechanism induced by three-dimensional shock wave and boundary layer in hypersonic flow. The interaction of three-dimensional shock waves and boundary layer plays important role in the complex flow feature in hypersonic rudder region. The contact surface induced by three-dimensional shock waves represents a local jet. When the flow jet impinges on the boundary layer of wall surface, the jet makes the boundary layer thinner and will inevitably cause local heat flux peak. The interaction configurations of three-dimensional shock wave play important role in the gasdynamic heating mechanisms of hypersonic complex flow.

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