Analysis of the biomechanical response of kidneys under blunt impact.
OBJECTIVE
This study addresses the biomechanical response of isolated kidneys to traumatic insult.


METHODS
Kidneys were subjected to blunt impact by using a freely swinging right cylindrical pendulum. Force-deformation characteristics were derived for 65 impacted adult pig kidneys. Renal injuries were classified by autopsy, and an injury risk analysis was performed. In addition a finite element model that simulated the experiments was implemented.


CONCLUSIONS
The kidneys showed a viscoelastic response. An energy-based injury threshold was identified, with a strain energy density of 21 kJ/m(3) corresponding to a 50-percent risk of renal injury level AIS3 or higher. Finally, the impact tests were simulated using a finite element model of the kidney to investigate relevant injury mechanisms. The model predicted the renal capsule and underlying parenchyma to first fail at an impact energy level of 4.0 J, consistent with experimental results.
Schmitt
Kai-Uwe
KU
Institute for Biomedical Engineering, Swiss Federal Institute of Technology (ETH) and University of Zurich, Switzerland. schmitt@biomed.ee.ethz.ch
Snedeker
Jess G
JG
D000063:Accidents, Traffic; D000818:Animals; D001344:Autopsy; D001696:Biomechanical Phenomena; D020342:Finite Element Analysis; D007668:Kidney / Q000293:injuries* / Q000473:pathology; D008962:Models, Theoretical; D012307:Risk Factors; D012421:Rupture; D013552:Swine; D014949:Wounds, Nonpenetrating / Q000473:pathology / Q000503:physiopathology*