Comparison of Posterior Fixation Strategies for Thoracolumbar Burst Fracture: A Finite Element Study

Abstract

The management of thoracolumbar (TL) burst fractures remained challenging. Due to the complex nature of the fractured vertebrae and the lack of clinical and biomechanical evidence, currently, there was still no guideline to select the optimal posterior fixation strategy for TL burst fracture. We utilized a T10-L3 TL finite element model to simulate L1 burst fracture and four surgical constructs with one or two-level suprajacent and infrajacent instrumentation (U1L1, U1L2, U2L1, and U2L2). The present study was aimed to compare the biomechanical properties and find an optimal fixation strategy for TL burst fracture in order to minimize motion in the fractured level without exerting significant burden in the construct. Our result showed that two-level infrajacent fixation (U1L2 and U2L2) resulted in greater motion reduction ranging from 66.0 to 87.3 precents compared to 32.0 to 47.3 percents in one-level infrajacent fixation. Flexion produced the largest pathological motion in the fractured level but the differences between the constructs were small, all within 0.26 degrees. Comparisons in implant stress showed that U2L1 and U2L2 had an average 25.3 and 24.8 percent less von Mises stress in the pedicle screws compared to U1L1 and U1L2, respectively. The construct of U2L1 had better preservation of physiological motion while providing sufficient ROM reduction at the fractured level. We suggested that U2L1 was a good alternative to the standard long-segment fixation with better preservation of motion and without an increased risk of implant failure.

Optimization of Spinal Reconstructions for Thoracolumbar Burst Fractures to Prevent Proximal Junctional Complications: A Finite Element Study

“…In addition, the construct of TCSR with SSPI can also provide sufficient stability to the fractured vertebral body, thereby reducing the number of fixed vertebral segments compared to conventional LSPI. As demonstrated in our study and in the literature, this configuration provides the additional advantage of preserving more vertebral motion segments with better physiologic motion and less overall ROM reduction [ 24 ].…”

“…The interior of the cortical surface contained cancellous bone assigned to C3D4 continuum elements. The posterior element and the facet were modeled according to the original geometry using C3D4 tetrahedron elements as previously described [ 23 , 24 ]. A three-dimensional surface-to-surface contact with friction was assigned to simulate the facet contact behavior with a finite sliding interaction defined to allow random motions, including sliding, rotation, and separation.…”

Finite element analysis of the indirect reduction of posterior pedicle screw fixation for a thoracolumbar burst fracture

“…Finite element analysis of thoracolumbar fracture can provide very meaningful digital orthopedic data for clinical practice, which is helpful for physicians to make appropriate surgical plans and engineering and technical personnel to improve material properties and optimize designs. [19–25]…”

“…Finite element analysis of thoracolumbar fracture can provide very meaningful digital orthopedic data for clinical practice, which is helpful for physicians to make appropriate surgical plans and engineering and technical personnel to improve material properties and optimize designs. [19][20][21][22][23][24][25] Based on previous related research, [26][27][28] this study established a finite element model of an L1 burst fracture. Because the finite element model requires the internal structure to be as regular as possible during the meshing process, the model was repaired and slightly modified during the introduction process; however, the basic shape of the structure was basically retained.…”

“…Material parameters of various parts of the spine and internal fixation. [18][19][20][21][22][23][24][25]…”