Optimum energy on the fragmentation of kidney stones by direct impact
Abstract
Purpose
This paper aims to describe a numerical approach to the fragmentation of kidney stones by direct impact.
Design/methodology/approach
The numerical approach consists of a Lagrangian finite element formulation with dynamic insertion of cohesive‐free surfaces. Cohesive free surfaces are governed by a damage constitutive model whereas the continuum part of the mesh remains linear elastic. The impact of the metallic probe of the medical device is modeled with a displacement control of the nodes inside the area of impact on the stone.
Findings
The results show the relation between the total energy transmitted during the impact with the damage and the fragmentation (number of fragments and number of microcrack clusters) of the kidney stone. The paper establishes the existence of both, an activation and saturation energy level, that delimit a range optimum working energy transmitted during the impact. In particular, the computations show that, for the calcium oxalate monohydrate stone, the maximum energy supplied by the medical device (Lithoclast) coincides with the saturation energy level.
Originality/value
In medical investigations, the experimentation is always restricted to the availability of patients or specimens. In the particular case of the elimination of renal calculi, the literature exhibits an extensive number of works reporting the practical experience of medical doctors. However, there is still a lack of information that might help to understand and to improve the comminution of kidney stones.
Keywords
Citation
Caballero, A. and Molinari, J. (2011), "Optimum energy on the fragmentation of kidney stones by direct impact", Engineering Computations, Vol. 28 No. 6, pp. 747-764. https://doi.org/10.1108/02644401111154655
Publisher
:Emerald Group Publishing Limited
Copyright © 2011, Emerald Group Publishing Limited