Biomechanical Analysis of Porous Additive Manufactured Cages for Lateral Lumbar Interbody Fusion: a Finite Element Analysis.

Biomechanical Analysis of Porous Additive Manufactured Cages for Lateral Lumbar Interbody Fusion: a Finite Element Analysis.

World Neurosurg. 2017 Dec 27;:

Authors: Zhang Z, Li H, Fogel GR, Liao Z, Li Y, Liu W

Abstract
BACKGROUND: A porous additive manufactured (AM) cage may provide stability similar to that of traditional solid cages, and may be beneficial to bone ingrowth. The biomechanical influence of various porous cages on stability, subsidence, stresses in cage, and facet contact force has not been fully described. The purpose of this study was to verify biomechanical effects of porous AM cages.
METHODS: The surgical FE models with various cages were constructed. The partially porous titanium (PPT) cages and fully porous titanium (FPT) cages were applied. The mechanical parameters of porous materials were obtained by mechanical test. Then the porous AM cages were compared to solid titanium (TI) cage and solid PEEK cage. The four motion modes were simulated. Range of motion (ROM), cage stress, endplate stress, and facet joint force (FJF) were compared.
RESULTS: For all the surgical models, ROM decreased by more than 90%. Compared with TI and PPT cages, PEEK and FPT cages substantially reduced the maximum stresses in cage and endplate in all motion modes. Compared with PEEK cages, the stresses in cage and endplate for FPT cages decreased, whereas the ROM increased. Compared among FPT cages, the stresses in cage and endplate decreased with increasing porosity, whereas ROM increased with increasing porosity. After interbody fusion, FJF was substantially reduced in all motion modes except for flexion.
CONCLUSIONS: Fully porous cages may offer an alternative to solid PEEK cages in lateral lumbar interbody fusion. However, it may be prudent to further increase the porosity of cage.

PMID: 29288855 [PubMed - as supplied by publisher]

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