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. 2021 Mar 24;16(1):213.
doi: 10.1186/s13018-021-02354-0.

Biomechanics of artificial pedicle fixation in a 3D-printed prosthesis after total en bloc spondylectomy: a finite element analysis

Xiaodong Wang  1 , Hanpeng Xu  1 , Ye Han  2 , Jincheng Wu  1 , Yang Song  1 , Yuanyuan Jiang  2 , Jianzhong Wang  2 , Jun Miao  3
Affiliations

Biomechanics of artificial pedicle fixation in a 3D-printed prosthesis after total en bloc spondylectomy: a finite element analysis

Xiaodong Wang et al. J Orthop Surg Res. .

Abstract

Background: This study compared the biomechanics of artificial pedicle fixation in spine reconstruction with a 3-dimensional (3D)-printed prosthesis after total en bloc spondylectomy (TES) by finite element analysis.

Methods: A thoracolumbar (T10-L2) finite element model was developed and validated. Two models of T12 TES were established in combination with different fixation methods: Model A consisted of long-segment posterior fixation (T10/11, L1/2) + 3D-printed prosthesis; and Model B consisted of Model A + two artificial pedicle fixation screws. The models were evaluated with an applied of 7.5 N·m and axial force of 200 N. We recorded and analyzed the following: (1) stiffness of the two fixation systems, (2) hardware stress in the two fixation systems, and (3) stress on the endplate adjacent to the 3D-printed prosthesis.

Results: The fixation strength of Model B was enhanced by the screws in the artificial pedicle, which was mainly manifested as an improvement in rotational stability. The stress transmission of the artificial pedicle fixation screws reduced the stress on the posterior rods and endplate adjacent to the 3D-printed prosthesis in all directions of motion, especially in rotation.

Conclusions: After TES, the posterior long-segment fixation combined with the anterior 3D printed prosthesis could maintain postoperative spinal stability, but adding artificial pedicle fixation increased the stability of the fixation system and reduced the risk of prosthesis subsidence and instrumentation failure.

Keywords: 3D-printed prosthesis; Finite element analysis; Spinal stability; TES.

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Conflict of interest statement

The authors have no conflicts of interest relevant to this article.

Figures

Fig. 1
Fig. 1
Different 3D models. a, b Intact model of T10–L2 including major ligaments. c Structure of the IVD. d Model of the 3D-printed prosthesis with artificial pedicle structure. e, f Model A: 3D-printed prosthesis with long-segment posterior fixation (T10/11 and L1/2). g, h Model B: Model A + two artificial pedicle fixation screws
Fig. 2
Fig. 2
Comparison between ROM values from the T12–L2 thoracolumbar model in this study and previously reported values
Fig. 3
Fig. 3
Stiffness of the intact thoracolumbar model (T10–L2) and two fixation models
Fig. 4
Fig. 4
Maximum von Mises stress on posterior rods
Fig. 5
Fig. 5
von Mises stress distribution on the posterior rods and artificial pedicle fixation screws during left rotation. Model A (left). Model B (right)
Fig. 6
Fig. 6
von Mises stress on the connection between the artificial pedicle of the 3D-printed prosthesis and the screws during left rotation in Model B
Fig. 7
Fig. 7
von Mises stress in the L1 superior endplate of the two fixation models
See this image and copyright information in PMC

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