title: Computational comparison of three posterior lumbar interbody fusion techniques by using porous titanium interbody cages with 50% porosity.
abstract: This study investigated the biomechanical response of porous cages and lumbar spine segments immediately after surgery and after bone fusion, in addition to the long-term effects of various posterior lumbar interbody fusion (PLIF) techniques, by using the finite element method. Lumbar L3-L4 models based on three PLIF techniques (a single cage at the center of the intervertebral space, a single cage half-anterior to the intervertebral space, and two cages bilateral to the intervertebral space) with and without bone ingrowth were used to determine the biomechanical response of porous cages and lumbar segments instrumented with porous titanium cages (cage porosity=50%, pore diameter=1mm). The results indicated that bone fusion enhanced the stability of the lumbar segments with porous cages without any posterior instrumentation and reduced the peak von Mises stress in the cortical bones and porous cages. Two cages placed bilateral to the intervertebral space achieved the highest structural stability in the lumbar segment and lowest von Mises stress in the cages under both bone fusion conditions. Under identical loading (2-Nm), the range of motion in the single cage at the center of the intervertebral space with bone fusion decreased by 11% (from 1.18° to 1.05°) during flexion and by 66.5% (from 4.46° to 1.5°) during extension in the single cage half-anterior to the intervertebral space with bone fusion compared with no-fusion models. Thus, two porous titanium cages with 50% porosity can achieve high stability of a lumbar segment with PLIF. If only one cage is available, placing the cage half-anterior to the intervertebral space is recommended for managing degenerated lumbar segments.
authors.affiliation: Department of Orthopaedic, Ministry of Health and Welfare Feng Yuan Hospital, Taichung City, Taiwan.
authors.forename: Yung-Heng
authors.initials: YH
authors.lastname: Lee
authors.affiliation: Department of Dental Technology and Materials Science, Central Taiwan University of Science and Technology, Taichung City, Taiwan.
authors.forename: Chi-Jen
authors.initials: CJ
authors.lastname: Chung
authors.affiliation: Department of Mechanical Engineering, University of Washington, Seattle City, WA, USA; Department of BioMedical Engineering, National Cheng Kung University, Tainan City, Taiwan.
authors.forename: Chih-Wei
authors.initials: CW
authors.lastname: Wang
authors.affiliation: Department of BioMedical Engineering, National Cheng Kung University, Tainan City, Taiwan; Metal Industries Research & Development Centre, Kaohsiung City, Taiwan.
authors.forename: Yao-Te
authors.initials: YT
authors.lastname: Peng
authors.affiliation: Department of BioMedical Engineering, National Cheng Kung University, Tainan City, Taiwan.
authors.forename: Chih-Han
authors.initials: CH
authors.lastname: Chang
authors.affiliation: Department of BioMedical Engineering, National Cheng Kung University, Tainan City, Taiwan; Department of Orthopaedic Surgery, Tainan Municipal Hospital, Tainan City, Taiwan.
authors.forename: Chih-Hsien
authors.initials: CH
authors.lastname: Chen
authors.affiliation: Department of BioMedical Engineering, National Cheng Kung University, Tainan City, Taiwan; Metal Industries Research & Development Centre, Kaohsiung City, Taiwan. Electronic address: yennien.chen@gmail.com.
authors.forename: Yen-Nien
authors.initials: YN
authors.lastname: Chen
authors.affiliation: Graduate Institute of Mechatronic System Engineering, National University of Tainan, Tainan City, Taiwan. Electronic address: ctli0412@gmail.com.
authors.forename: Chun-Ting
authors.initials: CT
authors.lastname: Li
mesh_terms: D003198:Computer Simulation; D006801:Humans; D008159:Lumbar Vertebrae / Q000473:pathology / Q000503:physiopathology; D008954:Models, Biological; D016062:Porosity; D013123:Spinal Fusion; D014025:Titanium
chemical_list: D014025:Titanium
keywords: Bone ingrowth; Finite element method; Lumbar L3-4; Porous interbody cage; Posterior lumbar interbody fusion