Treatment of thoracolumbar burst fractures by short-segment pedicle screw fixation using a combination of two additional pedicle screws and vertebroplasty at the level of the fracture: a finite element analysis

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.

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Posterior monoaxial screw fixation combined with distraction-compression technology assisted endplate reduction for thoracolumbar burst fractures: a retrospective study

BMC Musculoskeletal Disorders ◽

10.1186/s12891-020-3038-6 ◽

2020 ◽

Vol 21 (1) ◽

Author(s):

Xuhong Xue ◽

Sheng Zhao

Keyword(s):

Retrospective Study ◽

Pedicle Screw ◽

Screw Fixation ◽

Pedicle Screws ◽

Pedicle Screw Fixation ◽

Thoracolumbar Burst Fractures ◽

Correction Rate ◽

Burst Fractures ◽

The Mean

Abstract Background The management of thoracolumbar burst fractures traditionally involves posterior pedicle screw fixation, but it has some drawbacks. The aim of this study is to evaluate the clinical and radiological outcomes of patients with thoracolumbar burst fractures. They were treated by a modified technique that monoaxial pedicle screws instrumentation and distraction-compression technology assisted end plate reduction. Methods From March 2014 to February 2016, a retrospective study including 42 consecutive patients with thoracolumbar burst fractures was performed. The patients had undergone posterior reduction and instrumentation with monoaxial pedicle screws. The fractured vertebrae were also inserted screws as a push point. The distraction -compression technology was used as assisting end plate reduction. All patients were followed up at a minimum of 2 years. These parameters including segmental kyphosis, severity of fracture, neurological function, canal compromise and back pain were evaluated in preoperatively, postoperatively and at the final follow-up. Results The average follow-up period was 28.9 ± 4.3 months (range, 24-39mo). No patients had postoperative implant failure at recent follow-up. The mean Cobb angle of the kyphosis was improved from 14.2°to 1.1° (correction rate 92.1%). At final follow-up there was 1.5% loss of correction. The mean preoperative wedge angle was improved from 17.1 ± 7.9°to 4.4 ± 3.7°(correction rate 74.3%). The mean anterior and posterior vertebral height also showed significant improvements postoperatively, which were maintained at the final follow-up(P < 0.05). The mean visual analogue scale (VAS) scores was 8 and 1.6 in preoperation and at the last follow-up, and there was significant difference (p < 0.05). Conclusion Based on our experience, distraction-compression technology can assist reduction of collapsed endplate directly. Satisfactory fracture reduction and correction of segmental kyphosis can be achieved and maintained with the use of monoaxial pedicle screw fixation including the fractured vertebra. It may be a good treatment approach for thoracolumbar burst fractures.

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

Spine Deformity ◽

10.1016/j.jspd.2014.03.002 ◽

2014 ◽

Vol 2 (4) ◽

pp. 248-259 ◽

Cited By ~ 7

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

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Short term functional and neurological outcome of short segment pedicle screw fixation in unstable thoracolumbar burst fractures

MedPulse International Journal of Orthopedics ◽

10.26611/10201025 ◽

2019 ◽

Vol 10 (2) ◽

pp. 35-39

Author(s):

Gurumurthy B ◽

◽

Madhukesh Rudramurthy ◽

Sujana Theja J S ◽

Manjunatha D N ◽

...

Keyword(s):

Pedicle Screw ◽

Neurological Outcome ◽

Screw Fixation ◽

Pedicle Screw Fixation ◽

Short Term ◽

Short Segment ◽

Thoracolumbar Burst Fractures ◽

Burst Fractures

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Biomechanical comparison of stand-alone and bilateral pedicle screws fixation for oblique lumbar inter-body fusion surgery – a finite element analysis

10.21203/rs.2.11748/v1 ◽

2019 ◽

Author(s):

guofang Fang ◽

yunzhi lin ◽

wenggang cui ◽

lili guo ◽

shihao Zhang ◽

...

Keyword(s):

Finite Element ◽

Pedicle Screw ◽

Screw Fixation ◽

Pedicle Screws ◽

Element Model ◽

Axial Rotation ◽

Pedicle Screw Fixation ◽

Element Analysis ◽

Intact Group ◽

Flexion Extension

Abstract Objectives: The aim of this study was to evaluate the biomechanical stability and safety in patients undergoing oblique lumbar inter-body fusion (OLIF) surgery with stand-alone (SA) and Bilateral pedicle screw fixation (BPSF). Methods: A finite element model of L4-L5 spinal unit was established and validated. Based on the validated model technique, function surgical models corresponding to SA, BPSF were created. Simulations employing the models were performed to investigate the OLIF surgery. A bending moment of 7.5 Nm and a 500 N follower load were applied to the models in flexion, extension, axial rotation and lateral bending. Finite element(FE) models were developed to compare the biomechanics of the intact group, SA, BPSF group. Results: Compared with the Range of motion (ROM) of the intact lumbar model, SA model decreased by 79.5% in flexion, 54.2% in extension, BPSF model decreased by 86.4% in flexion, 70.8% in extension. Compared with the BPSF, the maximum stresses of L4 inferior endplate (IEP) and L5 superior endplate (SEP) increased significantly in SA model, L4 IEP increased to 49.7MPa in extension, L5 SEP increased to 47.7MPa in flexion. Conclusions: OLIF surgery with BPSF could reduce the max stresses of the endplate which may reduce cage sedimentation incidence. However, OLIF surgery with SA could not provide enough rigidity for the fusion segment in osteoporosis patients which may increase the cage sedimentation incidence. Keywords: OLIF; Pedicle screw fixation; spinal fusion; finite element

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Biomechanical Comparison of Different Pedicle Screw Fixations for Thoracolumbar Burst Fractures Using Finite Element Method

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.117-119.699 ◽

2011 ◽

Vol 117-119 ◽

pp. 699-702 ◽

Cited By ~ 2

Author(s):

Dong Mei Wang ◽

Du Fang Shi ◽

Xi Lei Li ◽

Jian Dong ◽

Chun Hui Wang ◽

...

Keyword(s):

Finite Element Method ◽

Finite Element ◽

Pedicle Screw ◽

Pedicle Screws ◽

Loading Conditions ◽

Lateral Bending ◽

Short Segment ◽

Thoracolumbar Burst Fractures ◽

Burst Fractures ◽

Short Segment Fixation

This study was designed to compare the biomechanical effects of three posterior fixations for thoracolumbar burst fractures using the finite element (FE) method. Five T11-L1 FE models, including the intact, the fractured at T12, the monosegment fixated at the level of the fracture, the short-segment fixated with four pedicle screws and the short-segment fixated with five pedicle screws, were created. And four loading conditions (flexion, extension, lateral bending and torsion) were imposed on these models and deformations in these models under different loading conditions were calculated by finite element method. The biomechanical effects of the three different pedicle screw fixations for thoracolumbar burst fractures were compared and analyzed. The results showed that the displacement level in monosegment fixation model was close to that in the intact one. The extension motion was more limited in short-segment fixation models than that in monosegment fixation model. Under the lateral bending condition, the level of the displacements in these models were similar and the peak rotation angles in the three fixation models were close to that in the intact one. The displacements in fractured T12 were increased in monosegment fixation model under all loading conditions. These indicated that the monosegment fixation couldn’t provide desirable stability for the fractured T11-L1 and the short-segment fixation with five pedicle screws was the best selection because of ideal stability and movability.

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