title: Finite element study of human lumbar disc nucleus replacements.
abstract: Currently, there are a number of nucleus replacements under development. The important concern is how well these implants duplicate the mechanical function of the native nucleus. This finite element model study aimed to investigate the influence of different nucleus replacements on the mechanical response of the disc. Models included partial, full, over-sized, partially saturated, elastic and poroelastic solid replacements. Over-sized nucleus replacements up to 25% yielded results that were comparable to those in the intact state. Differences were much greater in cases with under-sized nucleus replacements. The effect was most pronounced for the 75% under-sized replacement that resembled the condition with a full nucleotomy. Nucleus implants with elastic properties substantially altered load transmission when 10% under-sized and over-sized replacements were considered. Compared to intact, the under-sized implants should be avoided when using biphasic materials with properties similar to the native nucleus, whereas for elastic replacements both under- and over-sized implants should not be used.
authors.affiliation: a Julius Wolff Institut, Charité - Universitätsmedizin Berlin, CVK , Institutsgebäude Süd/Südstraße 2, Augustenburger Platz 1, 13353 Berlin , Germany.
authors.forename: Hendrik
authors.initials: H
authors.lastname: Schmidt
authors.forename: Maxim
authors.initials: M
authors.lastname: Bashkuev
authors.forename: Fabio
authors.initials: F
authors.lastname: Galbusera
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Wilke
authors.forename: Aboulfazl
authors.initials: A
authors.lastname: Shirazi-Adl
mesh_terms: D004548:Elasticity; D020342:Finite Element Analysis; D006801:Humans; D020100:Hydrogels / Q000737:chemistry; D007403:Intervertebral Disc / Q000502:physiology*; D008159:Lumbar Vertebrae / Q000502:physiology*; D010539:Permeability; D016062:Porosity; D019736:Prostheses and Implants; D013997:Time Factors
chemical_list: D020100:Hydrogels
keywords: finite element analysis; implants; intervertebral disc; nucleus replacement; poroelastic