title: Feasibility of compressive follower load on spine in a simplified dynamic state: a simulation study.
abstract: This study investigated that the spinal MFs can create compressive follower loads (CFLs) in the lumbar spine in a dynamic state. Three-dimensional optimization and finite element (FE) models of the spinal system were developed and validated using reported experimental data. An optimization analysis was performed to determine the MFs that create CFLs in the lumbar spine in various sagittal postures from 10° extension to 40° flexion. Optimization solutions for the MFs, CFLs, and follower load path (FLP) location were feasible for all studied postures. The FE predictions demonstrated that MFs which created CFLs along the base spinal curve connecting the geometrical centers or along a curve in its vicinity (within anterior or posterior shift by 2 mm) produced stable deformation of the lumbar spine in the neutral standing and flexed postures, whereas the MFs which created the smallest CFLs resulted in unstable deformation. For extended postures, however, finding CFLs creating MFs that produce stable deformation of the extended spine was not possible. The results of this study support the hypothesis that the spinal muscles may stabilize the spine via the CFL mechanism.
authors.affiliation: Humanetics Innovative Solutions Inc., Plymouth, Michigan, USA Department of Biomedical Engineering, The University of Iowa, Iowa City, Iowa, USA.
authors.forename: Byeong Sam
authors.initials: BS
authors.lastname: Kim
authors.affiliation: Department of Biomedical Engineering, The University of Iowa, Iowa City, Iowa, USA.
authors.forename: Tae-Hong
authors.initials: TH
authors.lastname: Lim
authors.affiliation: Division of Biomedical Engineering, Chonbuk National University, Jeonju, Republic of Korea.
authors.forename: Tae Kyu
authors.initials: TK
authors.lastname: Kwon
authors.affiliation: Division of Biomedical Engineering, Chonbuk National University, Jeonju, Republic of Korea Medical School, Chonbuk National University, Jeonju, Republic of Korea.
authors.forename: Kap-Soo
authors.initials: KS
authors.lastname: Han
mesh_terms: D019245:Compressive Strength / Q000502:physiology; D003198:Computer Simulation; D055119:Elastic Modulus / Q000502:physiology; D005240:Feasibility Studies; D006801:Humans; D008159:Lumbar Vertebrae / Q000502:physiology*; D008954:Models, Biological; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D016059:Range of Motion, Articular / Q000502:physiology; D013314:Stress, Mechanical; D013718:Tensile Strength / Q000502:physiology; D016474:Weight-Bearing / Q000502:physiology*; D021801:Zygapophyseal Joint / Q000502:physiology*
keywords: Compressive follower load; finite element model; lumbar Spine; muscle forces; spine biomechanics