TY - JOUR
T1 - Biomechanical analysis of cages for posterior lumbar interbody fusion
AU - Fantigrossi, Alfonso
AU - Galbusera, Fabio
AU - Raimondi, Manuela Teresa
AU - Sassi, Marco
AU - Fornari, Maurizio
PY - 2007/1
Y1 - 2007/1
N2 - Interbody fusions using intervertebral cages have become increasingly common in spinal surgery. Computational simulations were conducted in order to compare different cage designs in terms of their biomechanical interaction with the spinal structures. Differences in cage design and surgical technique may significantly affect the biomechanics of the fused spine segment, but little knowledge is available on this topic. In the present study, four 3D finite element models were developed, reproducing the human L4-L5 spinal unit in intact condition and after implantation of three different cage models. The intact model consisted of two vertebral bodies and relevant laminae, facet joints, main ligaments and disc. The instrumented models reproduced the post-operative conditions resulting after implant of the different cages. The three considered devices were hollow threaded titanium cages, the BAK™ (Zimmer Centerpulse, Warsaw, IN, USA), the Interfix™ and the Interfix Fly™ (both by Medtronic Sofamor Danek, Memphis, TN, USA). Simulations were run imposing various loading conditions, under a constant compressive preload. A great increase in the stiffness induced on the spinal segment by all cages was observed in all the considered loading cases. Stress distributions on the bony surface were evaluated and discussed. The differences observed between the biomechanics of the instrumented models were associated with the geometrical and surgical features of the devices.
AB - Interbody fusions using intervertebral cages have become increasingly common in spinal surgery. Computational simulations were conducted in order to compare different cage designs in terms of their biomechanical interaction with the spinal structures. Differences in cage design and surgical technique may significantly affect the biomechanics of the fused spine segment, but little knowledge is available on this topic. In the present study, four 3D finite element models were developed, reproducing the human L4-L5 spinal unit in intact condition and after implantation of three different cage models. The intact model consisted of two vertebral bodies and relevant laminae, facet joints, main ligaments and disc. The instrumented models reproduced the post-operative conditions resulting after implant of the different cages. The three considered devices were hollow threaded titanium cages, the BAK™ (Zimmer Centerpulse, Warsaw, IN, USA), the Interfix™ and the Interfix Fly™ (both by Medtronic Sofamor Danek, Memphis, TN, USA). Simulations were run imposing various loading conditions, under a constant compressive preload. A great increase in the stiffness induced on the spinal segment by all cages was observed in all the considered loading cases. Stress distributions on the bony surface were evaluated and discussed. The differences observed between the biomechanics of the instrumented models were associated with the geometrical and surgical features of the devices.
KW - Biomechanics
KW - Cage
KW - Finite element model
KW - Interbody fusion
KW - Lumbar
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U2 - 10.1016/j.medengphy.2006.02.007
DO - 10.1016/j.medengphy.2006.02.007
M3 - Article
C2 - 16563847
AN - SCOPUS:33750493325
VL - 29
SP - 101
EP - 109
JO - Medical Engineering and Physics
JF - Medical Engineering and Physics
SN - 1350-4533
IS - 1
ER -