Individualized prediction of pedicle screw fixation strength with a finite element model

Abstract Objectives: The aim of this study was to evaluate the biomechanical stability and safety in patients undergoing oblique lumbar inter-body fusion (OLIF) surgery with stand-alone (SA) and Bilateral pedicle screw fixation (BPSF). Methods: A finite element model of L4-L5 spinal unit was established and validated. Based on the validated model technique, function surgical models corresponding to SA, BPSF were created. Simulations employing the models were performed to investigate the OLIF surgery. A bending moment of 7.5 Nm and a 500 N follower load were applied to the models in flexion, extension, axial rotation and lateral bending. Finite element(FE) models were developed to compare the biomechanics of the intact group, SA, BPSF group. Results: Compared with the Range of motion (ROM) of the intact lumbar model, SA model decreased by 79.5% in flexion, 54.2% in extension, BPSF model decreased by 86.4% in flexion, 70.8% in extension. Compared with the BPSF, the maximum stresses of L4 inferior endplate (IEP) and L5 superior endplate (SEP) increased significantly in SA model, L4 IEP increased to 49.7MPa in extension, L5 SEP increased to 47.7MPa in flexion. Conclusions: OLIF surgery with BPSF could reduce the max stresses of the endplate which may reduce cage sedimentation incidence. However, OLIF surgery with SA could not provide enough rigidity for the fusion segment in osteoporosis patients which may increase the cage sedimentation incidence. Keywords: OLIF; Pedicle screw fixation; spinal fusion; finite element

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Impact of Screw Diameter and Length on Pedicle Screw Fixation Strength in Osteoporotic Vertebrae: A Finite Element Analysis

Asian Spine Journal ◽

10.31616/asj.2020.0353 ◽

2020 ◽

Author(s):

Keitaro Matsukawa ◽

Yoshiyuki Yato ◽

Hideaki Imabayashi

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Pedicle Screw ◽

Screw Fixation ◽

Pedicle Screw Fixation ◽

Fixation Strength ◽

Element Analysis ◽

Screw Diameter

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Evaluation and Analysis of strain in the screw head for lumbar pedicle screw fixation: An experimental and finite element study

International Journal for Multiscale Computational Engineering ◽

10.1615/intjmultcompeng.2021039052 ◽

2021 ◽

Author(s):

Masud Rana ◽

Sourav Majumdar ◽

Pushpdant Jain ◽

Anindya Malas ◽

Rururaja Pradhan ◽

...

Keyword(s):

Finite Element ◽

Pedicle Screw ◽

Screw Fixation ◽

Pedicle Screw Fixation ◽

Screw Head ◽

Finite Element Study ◽

Lumbar Pedicle ◽

Element Study

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Treatment of Thoracolumbar Fractures Through Different Short Segment Pedicle Screw Fixation Techniques: A Finite Element Analysis

Orthopaedic Surgery ◽

10.1111/os.12643 ◽

2020 ◽

Vol 12 (2) ◽

pp. 601-608

Author(s):

Tie‐nan Wang ◽

Bao‐lin Wu ◽

Rui‐meng Duan ◽

Ya‐shuai Yuan ◽

Ming‐jia Qu ◽

...

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Pedicle Screw ◽

Screw Fixation ◽

Pedicle Screw Fixation ◽

Thoracolumbar Fractures ◽

Short Segment ◽

Element Analysis ◽

Fixation Techniques

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Finite Element Study to Evaluate the Biomechanical Performance of the Spine After Augmenting Percutaneous Pedicle Screw Fixation With Kyphoplasty in the Treatment of Burst Fractures

Journal of Biomechanical Engineering ◽

10.1115/1.4039174 ◽

2018 ◽

Vol 140 (6) ◽

Cited By ~ 2

Author(s):

Shady S. Elmasry ◽

Shihab S. Asfour ◽

Francesco Travascio

Keyword(s):

Finite Element ◽

Pedicle Screw ◽

Fatigue Testing ◽

Screw Fixation ◽

Pedicle Screw Fixation ◽

Thoracolumbar Burst Fractures ◽

Hardware Failure ◽

Burst Fractures ◽

Percutaneous Pedicle Screw ◽

Percutaneous Pedicle Screw Fixation

Percutaneous pedicle screw fixation (PPSF) is a well-known minimally invasive surgery (MIS) employed in the treatment of thoracolumbar burst fractures (TBF). However, hardware failure and loss of angular correction are common limitations caused by the poor support of the anterior column of the spine. Balloon kyphoplasty (KP) is another MIS that was successfully used in the treatment of compression fractures by augmenting the injured vertebral body with cement. To overcome the limitations of stand-alone PPSF, it was suggested to augment PPSF with KP as a surgical treatment of TBF. Yet, little is known about the biomechanical alteration occurred to the spine after performing such procedure. The objective of this study was to evaluate and compare the immediate post-operative biomechanical performance of stand-alone PPSF, stand-alone-KP, and KP-augmented PPSF procedures. Novel three-dimensional (3D) finite element (FE) models of the thoracolumbar junction that describes the fractured spine and the three investigated procedures were developed and tested under mechanical loading conditions. The spinal stiffness, stresses at the implanted hardware, and the intradiscal pressure at the upper and lower segments were measured and compared. The results showed no major differences in the measured parameters between stand-alone PPSF and KP-augmented PPSF procedures, and demonstrated that the stand-alone KP may restore the stiffness of the intact spine. Accordingly, there was no immediate post-operative biomechanical advantage in augmenting PPSF with KP when compared to stand-alone PPSF, and fatigue testing may be required to evaluate the long-term biomechanical performance of such procedures.

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