|Title:||Removal of fixation construct could mitigate adjacent segment stress after lumbosacral fusion: A finite element analysis||Authors:||Hsieh Y.-Y.
|Issue Date:||2017||Journal Volume:||43||Start page/Pages:||115-120||Source:||Clinical Biomechanics||Abstract:||
Background data Combined usage of posterior lumbar interbody fusion and transpedicular fixation has been extensively used to treat the various lumbar degenerative disc diseases. The transpedicular fixator aims to increase stability and enhance the fusion rate. However, how the fused disc and bridged vertebrae respectively affect adjacent-segment diseases progression is not yet clear. Methods Using a validated lumbosacral finite-element model, three variations at the L4–L5 segment were analyzed: 1) moderate disc degeneration, 2) instrumented with a stand-alone cage and pedicle screw fixators, and 3) with the cage only after fusion. The intersegmental angles, disc stresses, and facet loads were examined. Four motion tests, flexion, extension, bending, and twisting, were also simulated. Findings The adjacent-segment disease was more severe at the cephalic segment than the caudal segment. After solid fusion and fixation, the increase in intersegmental angles, disc stresses and facet loads of the adjacent segments were about 57.6%, 47.3%, and 59.6%, respectively. However, these changes were reduced to 30.1%, 22.7%, and 27.0% after removal of the fixators. This was attributed to the differences between the biomechanical characteristics of the fusion and fixation mechanisms. Interpretation Fixation superimposes a stiffer constraint on the mobility of the bridged segment than fusion. The current study suggested that the removal of spinal fixators after complete fusion could decrease the stress at adjacent segments. Through a minimally invasive procedure, we could reduce secondary damage to the paraspinal structures while removing the fixators, which is of utmost concern to surgeons. ? 2017 The Authors
|URI:||https://scholars.lib.ntu.edu.tw/handle/123456789/515584||ISSN:||0268-0033||DOI:||10.1016/j.clinbiomech.2017.02.011||SDG/Keyword:||Bending tests; Biomechanical characteristics; Degenerative disc disease; Fixation mechanisms; Interbody fusion; Lumbosacral Fusion; Minimally invasive; Posterior lumbar interbody fusions; Spinal fixator; Finite element method; Article; biomechanics; device removal; finite element analysis; intervertebral disk degeneration; kinematics; kinetics; mechanical stress; motion; pedicle screw; posterior lumbar interbody fusion; priority journal; simulation; spine fixation device; spine stabilization; device removal; devices; disease exacerbation; finite element analysis; human; internal fixator; joint characteristics and functions; lumbar vertebra; pathophysiology; procedures; sacrum; spine fusion; Biomechanical Phenomena; Device Removal; Disease Progression; Finite Element Analysis; Humans; Internal Fixators; Intervertebral Disc Degeneration; Lumbar Vertebrae; Pedicle Screws; Range of Motion, Articular; Sacrum; Spinal Fusion
|Appears in Collections:||醫學院附設醫院 (臺大醫院)|
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