Biomechanical effects of posterior pedicle fixation techniques on the adjacent segment for the treatment of thoracolumbar burst fractures: a biomechanical analysis

Wang, Wei; Pei, Baoqing; Pei, Yuyang; Shi, Zhenpeng; Kong, Chao; Wu, Xueqing; Wu, Nan; Fan, Yubo; Lu, Shibao

doi:10.1080/10255842.2019.1631286

“…junctions predicted by the model were in agreement with experimental data from previous studies [22][23][24], thus validating the current thoracolumbar model.…”

Section: Resultssupporting

confidence: 89%

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

Wang

¹

,

Xu

²

,

Ye³

et al. 2021

Preprint

0

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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.

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“…In order to validate the models, the ROM of T7–T8 and T10–T11 under the same loading conditions were compared with previous studies under the same loading conditions, as shown in Figure 3 ( Panjabi et al, 1976 ; Ottardi et al, 2016 ; Zhang et al, 2020 ). The stress values of screws obtained with surgical model (minimum: 25 MPa, maximum: 139 MPa) were of the same order of magnitude as those calculated in previous studies reporting approximate values [minimum: 26 MPa and maximum: 133 MPa from Alizadeh et al (2013) and minimum: 70 MPa and maximum: 250 MPa from Wang W. et al (2019) ].…”

Section: Resultssupporting

confidence: 77%

“…ROM of T7−T8 and T10−T11 were measured and compared with previous study separately ( Panjabi et al, 1976 ; Ottardi et al, 2016 ; Zhang et al, 2020 ). In addition, the stress of rods and screws in postoperative models were compared with data from similar literatures ( Alizadeh et al, 2013 ; Wang W. et al, 2019 ).…”

Section: Methodsmentioning

confidence: 99%

Biomechanical Evaluation and the Assisted 3D Printed Model in the Patient-Specific Preoperative Planning for Thoracic Spinal Tuberculosis: A Finite Element Analysis

Wang

¹

,

Ke

²

,

Hua

³

et al. 2020

Front. Bioeng. Biotechnol.

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Posterior fixation is superior to anterior fixation in the correction of kyphosis and maintenance of spinal stability for the treatment of thoracic spinal tuberculosis. However, the process of selecting the appropriate spinal fixation method remains controversial, and preoperative biomechanical evaluation has not yet been investigated. In this study, we aimed to analyze the application of the assisted finite element analysis (FEA) and the three-dimensional (3D) printed model for the patient-specific preoperative planning of thoracic spinal tuberculosis. An adult patient with thoracic spinal tuberculosis was included. A finite element model of the T7−T11 thoracic spine segments was reconstructed to analyze the biomechanical effect of four different operative constructs. The von Mises stress values of the implants in the vertical axial load and flexion and extension conditions under a 400-N vertical axial pre-load and a 10-N⋅m moment were calculated and compared. A 3D printed model was used to describe and elucidate the patient’s condition and simulate the optimal surgical design. According to the biomechanical evaluation, the patient-specific preoperative surgical design was prepared for implementation. The anterior column, which was reconstructed with titanium alloy mesh and a bone graft with posterior fixation using seven pedicle screws (M+P) and performed at the T7–T11 level, decreased the von Mises stress placed on the right rod, T7 pedicle screw, and T11 pedicle. Moreover, the M+P evaded the left T9 screw without load bearing. The 3D printed model and preoperative surgical simulation enhanced the understanding of the patient’s condition and facilitated patient-specific preoperative planning. Good clinical results, including no complication of implants, negligible loss of the Cobb angle, and good bone fusion, were achieved using the M+P surgical design. In conclusion, M+P was recommended as the optimal method for preoperative planning since it enabled the preservation of the normal vertebra and prevented unnecessary internal fixation. Our study indicated that FEA and the assisted 3D printed model are tools that could be extremely useful and effective in the patient-specific preoperative planning for thoracic spinal tuberculosis, which can facilitate preoperative surgical simulation and biomechanical evaluation, as well as improve the understanding of the patient’s condition.

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“…Figure 2 shows the comparison between the range of motion (ROM) values for T12-L2 junctions obtained in this study and previously published data from biomechanical and finite element analysis experiments measuring flexion, extension, lateral bending, and axial rotation. The ROM for T12-L2 junctions predicted by the model were in agreement with experimental data from previous studies [22][23][24], thus validating the current thoracolumbar model.…”

Section: Assessment Indicessupporting

confidence: 88%

Biomechanics of Artificial Pedicle Fixation in a 3d-printed Prosthesis After Total en Bloc Spondylectomy: A Finite Element Analysis

Wang

¹

,

Xu

²

,

Ye³

et al. 2020

Preprint

View full text Add to dashboard Cite

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.

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Biomechanical effects of posterior pedicle fixation techniques on the adjacent segment for the treatment of thoracolumbar burst fractures: a biomechanical analysis

Cited by 34 publications

References 29 publications

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

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

Biomechanical Evaluation and the Assisted 3D Printed Model in the Patient-Specific Preoperative Planning for Thoracic Spinal Tuberculosis: A Finite Element Analysis

Biomechanics of Artificial Pedicle Fixation in a 3d-printed Prosthesis After Total en Bloc Spondylectomy: A Finite Element Analysis

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