title: Effect of bone graft characteristics on the mechanical behavior of the lumbar spine.
abstract: There is little information about the influence of bone graft size, position and elasticity on the mechanical behavior of the lumbar spine. Intersegmental motion, intradiscal pressure and stresses in the lumbar spine were calculated using a three-dimensional, nonlinear finite element model which included an internal spinal fixation device and a bone graft. Cross-sectional area, position, and elastic modulus of the graft were varied in this study. Bone grafts, especially very stiff ones, increase stresses on adjacent endplates. Though larger grafts lead to less contact pressure, it is difficult to judge the quality of different bone graft positions. In general, ventral flexion results in lower maximum contact pressure than lateral bending. There is always little intersegmental rotation in the bridged region compared with that of an intact spine.A larger graft with low stiffness should be favored from a mechanical point of view. Patients should avoid lateral bending of the upper body shortly after surgery.
authors.affiliation: Biomechanics Laboratory, University Hospital Benjamin Franklin, Free University of Berlin, Hindenburgdamm 30, 12203 Berlin, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Zander
authors.forename: Antonius
authors.initials: A
authors.lastname: Rohlmann
authors.forename: Constantin
authors.initials: C
authors.lastname: Klöckner
authors.forename: Georg
authors.initials: G
authors.lastname: Bergmann
mesh_terms: D001696:Biomechanical Phenomena; D016025:Bone Transplantation / Q000502:physiology* / Q000592:standards; D002102:Cadaver; D004548:Elasticity; D020342:Finite Element Analysis; D006801:Humans; D008159:Lumbar Vertebrae / Q000502:physiology*; D013123:Spinal Fusion / Q000592:standards; D013314:Stress, Mechanical