title: Application of an asymmetric finite element model of the C2-T1 cervical spine for evaluating the role of soft tissues in stability.
abstract: Different finite element models of the cervical spine have been suggested for evaluating the roles of ligaments, facet joints, and disks in the stability of cervical spine under sagittal moments. However, no comprehensive study on the response of the full cervical spine that has used a detailed finite element (FE) model (C2-T1) that considers the asymmetry about the mid-sagittal plane has been reported. The aims of this study were to consider asymmetry in a FE model of the full cervical spine and to investigate the influences of ligaments, facet joints, and disk nucleus on the stability of the asymmetric model during flexion and extension. The model was validated against various published in vitro studies and FE studies for the three main loading planes. Next, the C4-C5 level was modified to simulate different cases to investigate the role of the soft tissues in segmental stability. The FE model predicted that excluding the interspinous ligament (ISL) from the index level would cause excessive instability during flexion and that excluding the posterior longitudinal ligament (PLL) or the ligamentum flavum (LF) would not affect segmental rotation. During extension, motion increased when the facet joints were excluded. The model without disk nucleus was unstable compared to the intact model at lower loads and exhibited a similar rotation response at higher loads.
authors.affiliation: Department of Mechanical Engineering, College of Engineering, Koc University, Rumelifeneri Yolu, Istanbul 34450, Turkey; Department of Neurosurgery, School of Medicine, Koc University, Rumelifeneri Yolu, Istanbul 34450, Turkey. Electronic address: erbulutdeniz@gmail.com.
authors.forename: D U
authors.initials: DU
authors.lastname: Erbulut
authors.affiliation: Department of Mechanical Engineering, College of Engineering, Koc University, Rumelifeneri Yolu, Istanbul 34450, Turkey.
authors.forename: I
authors.initials: I
authors.lastname: Zafarparandeh
authors.affiliation: Department of Mechanical Engineering, College of Engineering, Koc University, Rumelifeneri Yolu, Istanbul 34450, Turkey.
authors.forename: I
authors.initials: I
authors.lastname: Lazoglu
authors.affiliation: Department of Neurosurgery, School of Medicine, Koc University, Rumelifeneri Yolu, Istanbul 34450, Turkey.
authors.forename: A F
authors.initials: AF
authors.lastname: Ozer
mesh_terms: D000328:Adult; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000502:physiology*; D003198:Computer Simulation; D003238:Connective Tissue / Q000502:physiology; D020342:Finite Element Analysis; D006801:Humans; D007403:Intervertebral Disc / Q000000981:diagnostic imaging / Q000502:physiology*; D008022:Ligaments / Q000000981:diagnostic imaging / Q000502:physiology*; D008297:Male; D008954:Models, Biological; D011859:Radiography; D016059:Range of Motion, Articular / Q000502:physiology*; D013314:Stress, Mechanical; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000502:physiology*; D016474:Weight-Bearing / Q000502:physiology; D021801:Zygapophyseal Joint / Q000000981:diagnostic imaging / Q000502:physiology*
keywords: Asymmetric; Cervical spine; Finite element model; Stability