On the load-sharing along the ligamentous lumbosacral spine in flexed and extended postures: Finite element study

Sadegh Naserkhaki, Jacob L. Jaremko, Samer Adeeb, Marwan El-Rich

Research output: Contribution to journalArticlepeer-review

54 Scopus citations

Abstract

A harmonic synergy between the load-bearing and stabilizing components of the spine is necessary to maintain its normal function. This study aimed to investigate the load-sharing along the ligamentous lumbosacral spine under sagittal loading. A 3D nonlinear detailed Finite Element (FE) model of lumbosacral spine with realistic geometry was developed and validated using wide range of numerical and experimental (in-vivo and in-vitro) data. The model was subjected to 500 N compressive Follower Load (FL) combined with 7.5 Nm flexion (FLX) or extension (EXT) moments. Load-sharing was expressed as percentage of total internal force/moment developed along the spine that each spinal component carried. These internal forces and moments were determined at the discs centres and included the applied load and the resisting forces in the ligaments and facet joints.The contribution of the facet joints and ligaments in supporting bending moments produced additional forces and moments in the discs. The intervertebral discs carried up to 81% and 68% of the total internal force in case of FL combined with FLX and EXT, respectively. The ligaments withstood up to 67% and 81% of the total internal moment in cases of FL combined with EXT and FLX, respectively. Contribution of the facet joints in resisting internal force and moment was noticeable at levels L4-S1 only particularly in case of FL combined with EXT and reached up 29% and 52% of the internal moment and force, respectively. This study demonstrated that spinal load-sharing depended on applied load and varied along the spine.

Original languageBritish English
Pages (from-to)974-982
Number of pages9
JournalJournal of Biomechanics
Volume49
Issue number6
DOIs
StatePublished - 11 Apr 2016

Keywords

  • Extension
  • Finite element analysis
  • Flexion
  • Follower load
  • Internal loads
  • Load-sharing
  • Lumbosacral spine
  • Spinal synergy
  • Static equilibrium

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