scholarly journals S2-alar-iliac screw and S1 pedicle screw fixation for the treatment of non-osteoporotic sacral fractures: a finite element study

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Jianxiong Zheng ◽  
Xiaoreng Feng ◽  
Jie Xiang ◽  
Fei Liu ◽  
Frankie K. L. Leung ◽  
...  
Keyword(s):  
Finite Element ◽  
Pedicle Screw ◽  
Screw Fixation ◽  
Relative Displacement ◽  
Pedicle Screw Fixation ◽  
Sacral Fracture ◽  
Type I ◽  
Vertical Stiffness ◽  
Fixation Methods ◽  
Sacral Fractures

Abstract Background Five different sacral fracture fixation methods were compared using finite element (FE) analysis to study their biomechanical characteristics. Methods Denis type I sacral fractures were created by FE modeling. Five different fixation methods for the posterior pelvic ring were simulated: sacroiliac screw (SIS), lumbopelvic fixation (LPF), transiliac internal fixator (TIFI), S2-alar-iliac (S2AI) screw and S1 pedicle screw fixation (S2AI-S1) and S2AI screw and contralateral S1 pedicle screw fixation (S2AI-CS1). Four different loading methods were implemented in sequence to simulate the force in standing, flexion, right bending and left twisting, respectively. Vertical stiffness, relative displacement and change in relative displacement were recorded and analyzed. Results As predicted by the FE model, the vertical stiffness of the five groups in descending order was S2AI-S1, SIS, S2AI-CS1, LPF and TIFI. In terms of relative displacement, groups S2AI-S1 and S2AI-CS1 displayed a lower mean relative displacement, although group S2AI-CS1 exhibited greater displacement in the upper sacrum than group S2AI-S1. Group SIS displayed a moderate mean relative displacement, although the displacement of the upper sacrum was smaller than the corresponding displacement in group S2AI-CS1, while groups LPF and TIFI displayed larger mean relative displacements. Finally, in terms of change in relative displacement, groups TIFI and LPF displayed the greatest fluctuations in their motion, while groups SIS, S2AI-S1 and S2AI-CS1 displayed smaller fluctuations. Conclusion Compared with SIS, unilateral LPF and TIFI, group S2AI-S1 displayed the greatest biomechanical stability of the Denis type I sacral fracture FE models. When the S1 pedicle screw insertion point on the affected side is damaged, S2AI-CS1 can be used as an appropriate alternative to S2AI-S1.

scholarly journals S2 Alar Iliac Screw and S1 Pedicle Screw Fixation for the Treatment of Sacral Fractures : A Finite Element Study

2021 ◽  
Author(s):  
Jianxiong Zheng ◽  
Xiaoreng Feng ◽  
Jie Xiang ◽  
Fei Liu ◽  
Frankie K L Leung ◽  
...  
Keyword(s):  
Finite Element ◽  
Pedicle Screw ◽  
Screw Fixation ◽  
Relative Displacement ◽  
Pedicle Screw Fixation ◽  
Fe Model ◽  
Type I ◽  
Vertical Stiffness ◽  
Fixation Methods ◽  
Sacral Fractures

Abstract Background: Five different sacral fracture fixation methods were compared using finite element (FE) analysis to study their biomechanical characteristics.Methods: Denis type I sacral fractures were created by FE modeling. Five different fixation methods for the posterior pelvic ring were simulated: sacroiliac screw (SIS), lumbopelvic fixation (LPF), transiliac internal fixator (TIFI), S2-alar-iliac (S2AI) screw and S1 pedicle screw fixation (S2AI-S1), and S2AI screw and contralateral S1 pedicle screw fixation (S2AI-CS1). Four different loading methods were implemented in sequence to simulate the force in standing, flexion, right bending, and left twisting, respectively. Vertical stiffness, relative displacement, and change in relative displacement were recorded and analyzed.Results: As predicted by the FE model, the vertical stiffness of the five groups in descending order were S2AI-S1, SIS, S2AI-CS1, LPF, TIFI. In terms of relative displacement, S2AI-S1 and S2AI-CS1 groups displayed a smaller mean relative displacement, although the S2AI-CS1 group exhibited greater displacement in the upper sacrum than the S2AI-S1 group. The SIS group displayed a moderate mean relative displacement, although the displacement of the upper sacrum was smaller than that of the S2AI-CS1 group. The LPF and TIFI groups displayed larger mean relative displacements. In terms of change in relative displacement, the TIFI and LPF groups displayed the greatest fluctuations in their motion, while the SIS, S2AI-S1, and S2AI-CS1 groups displayed smaller fluctuations.Conclusion: Compared with SIS, unilateral LPF and TIFI, S2AI-S1 displayed the greatest biomechanical stability of the FE models and can be used as a new method for the treatment of sacral fractures. When the S1 pedicle screw insertion point on the affected side is damaged, S2AI-CS1 can be used as a good alternative to S2AI-S1.

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

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

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

2018 ◽  
Vol 140 (6) ◽  
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.

The Benefits of Cement Augmentation of Pedicle Screw Fixation Are Increased in Osteoporotic Bone: A Finite Element Analysis

2014 ◽  
Vol 2 (4) ◽  
pp. 248-259 ◽  
Author(s):  
Wenhai Wang ◽  
George R. Baran ◽  
Hitesh Garg ◽  
Randal R. Betz ◽  
Missoum Moumene ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Pedicle Screw ◽  
Screw Fixation ◽  
Pedicle Screw Fixation ◽  
Cement Augmentation ◽  
Osteoporotic Bone ◽  
Element Analysis

Design of Patient Specific Spinal Implant (Pedicle Screw Fixation) using FE Analysis and Soft Computing Techniques

2020 ◽  
Vol 16 (4) ◽  
pp. 371-382 ◽  
Author(s):  
Jayanta Kumar Biswas ◽  
Swati Dey ◽  
Santanu Kumar Karmakar ◽  
Amit Roychowdhury ◽  
Shubhabrata Datta
Keyword(s):  
Finite Element ◽  
Pedicle Screw ◽  
Screw Fixation ◽  
Desirability Function ◽  
Strain Difference ◽  
Pedicle Screw Fixation ◽  
Patient Specific ◽  
Spinal Implant ◽  
Spinal Implants ◽  
Soft Computing Techniques

Background: This work uses genetic algorithm (GA) for optimum design of patient specific spinal implants (pedicle screw) with varying implant diameter and bone condition. The optimum pedicle screw fixation in terms of implant diameter is on the basis of minimum strain difference from intact (natural) to implantation at peri-prosthetic bone for the considered six different peri-implant positions. Methods: This design problem is expressed as an optimization problem using the desirability function, where the data generated by finite element analysis is converted into an artificial neural network (ANN) model. The finite element model is generated from CT scan data. Thereafter all the ANN predictions of the microstrain in six positions are converted to unitless desirability value varying between 0 and 1, which is then combined to form the composite desirability. Maximization of the composite desirability is done using GA where composite desirability should be made to go up as close as possible to 1. If the composite desirability is 1, then all ‘strain difference values in 6 positions’ are 0. Results: The optimum solutions obtained can easily be used for making patient-specific spinal implants.

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