Analysis of biomechanical changes after removal of instrumentation in lumbar arthrodesis by finite element analysis.
The purpose of this study is to investigate the change in biomechanical milieu following removal of pedicle screws in instrumented single level lumbar arthrodesis. Using a validated finite element (FE) model of the intact lumbar spine (L2-5), two scenarios of L3-4 lumbar fusion were simulated: posterolateral fusion (PLF) at L3-4 using pedicle screws (PLF with pedicle screws; WiP) and L3-4 lumbar posterolateral fusion state after removal of pedicle screws (PLF without pedicle screws; WoP). The WiP model had greater range of motion (ROM) at each adjacent segment than the WoP model. This phenomenon became pronounced at the proximal adjacent segment under flexion moment. Similarly, removal of pedicle screws (the WoP model) relieved the maximal von Mises stress at adjacent segments under 4 moments compared to the WiP model. This study demonstrated that removal of pedicle screws could decrease stiffness of fusion segments, which would reduce the disk stress of adjacent segments.
Kim
Ho-Joong
HJ
Yonsei sarang Hospital, Seoul, Korea.
Chun
Heoung-Jae
HJ
Moon
Seong-Hwan
SH
Kang
Kyoung-Tak
KT
Kim
Hak-Sun
HS
Park
Jin-Oh
JO
Moon
Eun-Su
ES
Sohn
Joon-Seok
JS
Lee
Hwan-Mo
HM
D001696:Biomechanical Phenomena; D001863:Bone Screws; D020878:Device Removal; D020342:Finite Element Analysis; D006801:Humans; D008159:Lumbar Vertebrae / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D016059:Range of Motion, Articular; D013123:Spinal Fusion / Q000295:instrumentation*