Journal article
Hinged-Dynamic Posterior Device Permits Greater Loads on the Graft and Similar Stability as Compared with Its Equivalent Rigid Device: A Three-Dimensional Finite Element Assessment
Journal of prosthetics and orthotics, Vol.13(1), pp.17-20
03/2001
DOI: 10.1097/00008526-200103000-00013
Abstract
A three-dimensional finite element model was developed to compare the load sharing capabilities of the hinged (or dynamic) versus rigid states of a posterior lumbar spinal fixation device. The objective was to show that a dynamic state of a fixation system enables more load to be transferred through the graft (anterior column) as compared with an alternative rigid state, without compromising the stability imparted to the stabilized segment. The stability aspects of the rigid and dynamic pedicle screw-rod/plate fixation devices have been reported. Load sharing data of dynamic devices, as compared with rigid devices, are sparse. A three-dimensional nonlinear, experimentally validated, midsagittal symmetric finite element model of a L3–L4 motion segment was used for analysis. The intact model was modified to simulate a facetectomy and stabilization using both the hinged and rigid devices. The nucleus of the intact model was replaced to simulate a graft of cancellous bone, cortical bone, or titanium. The hinged device allowed for greater axial displacement while it maintained rotational stability similar to that of the rigid device. As the stiffness of the nucleus was increased from cancellous bone to titanium, the hinged device allowed a greater load through the nucleus compared with the rigid device predictions. However, the difference in load through the nucleus was minimal for the cortical and titanium grafts. The load transferred through the nucleus was greater for the hinged device, while it imparted rotational stability similar to the rigid device. Thus, a hinged screw-rod device offers a more favorable environment for enhanced fusion of the graft. Finite element models of a destabilized lumbar motion segment supplemented by a hinged or rigid posterior fixation device predicted that the hinged design permits greater load through the nucleus without any decrease in the rotational stability. Such systems are expected to enhance the fusion process.
Details
- Title: Subtitle
- Hinged-Dynamic Posterior Device Permits Greater Loads on the Graft and Similar Stability as Compared with Its Equivalent Rigid Device: A Three-Dimensional Finite Element Assessment
- Creators
- Vijay K GoelRegina J KonzH. T ChangNicole M GroslandLeon J GroblerK. D Chesmel
- Resource Type
- Journal article
- Publication Details
- Journal of prosthetics and orthotics, Vol.13(1), pp.17-20
- DOI
- 10.1097/00008526-200103000-00013
- ISSN
- 1040-8800
- eISSN
- 1534-6331
- Language
- English
- Date published
- 03/2001
- Academic Unit
- Roy J. Carver Department of Biomedical Engineering; Orthopedics and Rehabilitation; Injury Prevention Research Center
- Record Identifier
- 9984040585202771
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