Biomechanical evaluation of a dynamic fusion cage design for cervical spine: A finite element study

Abstract

Spinal interbody fusion is the most common surgery for treatment of disc degeneration, but the increased stress and compensatory range of motion at adjacent level have been noted. The dynamic cage design becomes an alternative strategy for dealing with problem of disc degeneration while the bony fusion is eventually required. Concept from a commercial cervical cage product with a 'Z'-shaped dynamic feature has been evaluated and compared with intact cervical spine and conventional cage design by finite element method. Physiological loadings have been applied for evaluating the effect of cage design on biomechanical performances including adjacent disc stress and segmental range of motion. Results revealed that dynamic characteristic of the dynamic cage design shall effectively reduce the stress and range of motion at the adjacent disc, compared with conventional solid cage design, by providing sufficient mobility by itself. Torsional mobility was constrained due to its geometrical restriction. The dynamic function of cervical cage design may protect the disc adjacent to treat level from over-stressed and excessive mobility in early stage after fusion surgery. Further clinical investigation is required to determine the efficacy of cervical fusion by certain cervical cage with 'Z'-shaped dynamic feature.

Formulation of a covalently bonded hydroxyapatite and poly(ether ether ketone) composite

“…Validation of these composites as spinal fusion device construction materials may be achieved utilising computer-modelling techniques prior to conducting pre-clinical studies. 56…”

Optimization of cervical cage and analysis of its base material: A finite element study

“…the contact point of two vertebrae) was 0.1. 21 To simulate a real situation, the surface between cage and vertebrae was defined as fixed surfaces with respect to each other. The deformation of the modeled cage and vertebrae is not necessarily linear, thus, the stiffness of the system changes with deformation over time.…”

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Bio-Functional Design, Application and Trends in Metallic Biomaterials

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