title: Finite element analysis for comparison of spinous process osteotomies technique with conventional laminectomy as lumbar decompression procedure.
abstract: OBJECTIVE
  The purpose of this study was to evaluate and compare the biomechanical behavior of the lumbar spine after posterior decompression with the spinous process osteotomy (SPiO) technique or the conventional laminectomy (CL) technique using a finite element (FE) model.
  
  
  METHODS
  Three validated lumbar FE models (L2-5) which represented intact spine and two decompression models using SPiO and CL techniques at the L3-4 segment were developed. In each model, the ranges of motion, the maximal von Mises stress of the annulus fibrosus, and the intradiscal pressures at the index segment (L3-4) and adjacent segments (L2-3 and L4-5) under 7.5 Nm moments were analyzed. Facet contact forces were also compared among three models under the extension and torsion moments.
  
  
  RESULTS
  Compared to the intact model, the CL and SPiO models had increased range of motion and annulus stress at both the index segment (L3-4) and the adjacent segments under flexion and torsion. However, the SPiO model demonstrated a reduced range of motion and annulus stress than the CL model. Both CL and SPiO models had an increase of facet contact force at the L3-4 segment under the torsion moment compared to that of the intact model. Under the extension moment, however, three models demonstrated a similar facet contact force even at the L3-4 model.
  
  
  CONCLUSIONS
  Both decompression methods lead to postoperative segmental instability compared to the intact model. However, SPiO technique leads to better segmental stability compared to the CL technique.
authors.affiliation: Spine Center and Department of Orthopedic Surgery, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Ho-Joong
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Department of Mechanical Engineering, Yonsei University, Seoul, Korea.
authors.forename: Heoung-Jae
authors.initials: HJ
authors.lastname: Chun
authors.affiliation: Department of Mechanical Engineering, Yonsei University, Seoul, Korea.
authors.forename: Kyoung-Tak
authors.initials: KT
authors.lastname: Kang
authors.affiliation: Department of Orthopedic Surgery, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Hwan-Mo
authors.initials: HM
authors.lastname: Lee
authors.affiliation: Department of Orthopedic Surgery, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Bong-Soon
authors.initials: BS
authors.lastname: Chang
authors.affiliation: Department of Orthopedic Surgery, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Choon-Ki
authors.initials: CK
authors.lastname: Lee
authors.affiliation: Spine Center and Department of Orthopedic Surgery, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea. highcervical@gmail.com.
authors.forename: Jin-S
authors.initials: JS
authors.lastname: Yeom
mesh_terms: D001696:Biomechanical Phenomena; D019299:Decompression, Surgical / Q000379:methods*; D020342:Finite Element Analysis; D006801:Humans; D007403:Intervertebral Disc / Q000503:physiopathology / Q000601:surgery; D007796:Laminectomy / Q000379:methods*; D008159:Lumbar Vertebrae / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D008953:Models, Anatomic; D010027:Osteotomy / Q000379:methods*; D016059:Range of Motion, Articular; D013314:Stress, Mechanical; D021801:Zygapophyseal Joint / Q000473:pathology / Q000503:physiopathology / Q000601:surgery
keywords: Lumbar spinal stenosis; conventional laminectomy; finite element model; spinous process osteotomies