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. 2018 Aug;97(34):e12046.
doi: 10.1097/MD.0000000000012046.

A finite element study on posterior short segment fixation combined with unilateral fixation using pedicle screws for stable thoracolumbar fracture

Yunshan Su  1 , Xiongfei Wang, Dong Ren, Yueju Liu, Shaoming Liu, Pengcheng Wang
Affiliations

A finite element study on posterior short segment fixation combined with unilateral fixation using pedicle screws for stable thoracolumbar fracture

Yunshan Su et al. Medicine (Baltimore). 2018 Aug.

Abstract

The objective of this study was to use finite element models to investigate the biomechanics of stable thoracolumbar burst fracture repair using unilateral short-segment fixation and 4 alternate pedicle screw systems.Four posterior pedicle screw systems were compared for unilateral short-segment fixation using finite element models: intermediate bilateral short pedicle screw fixation, intermediate bilateral long pedicle screw fixation, intermediate unilateral short pedicle screw fixation, and intermediate unilateral long pedicle screw fixation. We compared range of motion (ROM), von Mises stresses on the implants, and stress on the intervertebral discs superior and inferior to the injured vertebra during simulated spinal movements.There were no significant differences in ROM, von Mises stress, or intervertebral disc stress among the 4 intermediate pedicle screw fixation techniques for all spinal movements evaluated. In addition, there were no consolidated trends depicting beneficial differences between the short and long screw models, or between the unilateral and bilateral screw models.ROM, von Mises stress, and intervertebral disc stress are the same across the 4, posterior short-segment fixation techniques evaluated using finite element models. The simplest technique-posterior short segment fixation combined with intermediate unilateral short pedicle screw fixation-is a feasible treatment strategy for stable thoracolumbar fracture.

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Conflict of interest statement

The authors report no conflicts of interest.

Figures

Figure 1
Figure 1
The T11-L2 finite element models.
Figure 2
Figure 2
The maximum range of motion.
Figure 3
Figure 3
The maximum von Mises stress.
Figure 4
Figure 4
von Mises stress nephogram of model C in spine extension (A) and model B in spine extension (B).
Figure 5
Figure 5
von Mises stress nephogram of model D in spine flexion (A), model A in left lateral bending (B), model D in right lateral bending (C), and model C in left lateral bending (D).
Figure 6
Figure 6
von Mises stress nephogram of model C in right axial rotation (A), model D in left axial rotation (B), model A in right axial rotation (C), and model B in left axial rotation (D).
Figure 7
Figure 7
The maximum stress on the intervertebral discs superior and inferior to the injured vertebra in the 4 models.
See this image and copyright information in PMC

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