Related Experiment Video
Updated: Jul 24, 2025
04:19
Minimally Invasive Treatment for Thoracolumbar Burst Fracture Using Sagittal Alignment Screws and A Trauma Reduction Device
Published on: November 8, 2024
481
Posterior Fixation for Different Thoracic-Sacrum Alignments Containing a Thoracolumbar Vertebral Fracture: A Finite
Norihiro Nishida1, Hidenori Suzuki1, Fei Jiang2
1Department of Orthopedic Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan.
World Neurosurgery
|July 8, 2023
Summary
Using six pedicle screws (6PS) for posterior fixation is more effective than four pedicle screws (4PS) in reducing stress on fractured vertebrae and spinal instrumentation, regardless of spinal alignment.
Area of Science:
- Spine biomechanics
- Orthopedic surgery
- Finite element analysis
Background:
- Thoracolumbar vertebral fractures are common, yet mechanical analyses of posterior fixation across different spinal alignments are lacking.
- Understanding the biomechanical impact of posterior fixation strategies is crucial for optimizing treatment outcomes in patients with spinal fractures.
Purpose of the Study:
- To investigate the mechanical effects of different posterior fixation constructs (4 vs. 6 pedicle screws) on fractured thoracolumbar vertebrae with varying spinal alignments.
- To compare the stress distribution on the fractured vertebra and instrumentation under flexion and extension in models with degenerative lumbar scoliosis (DLS) and adolescent idiopathic scoliosis (AIS).
Main Methods:
- A three-dimensional finite element model of the T1-sacrum was developed, incorporating three spinal alignment models: intact, DLS, and AIS.
- A burst fracture was simulated at the L1 vertebral level, and posterior fixation was modeled using 4 pedicle screws (4PS) and 6 pedicle screws (6PS).
- T1 was subjected to a 4 Nm moment simulating flexion and extension to analyze stress patterns.
Main Results:
- Vertebral stress at the L1 fracture site significantly increased (>190%) compared to non-fractured models across all alignments.
- Posterior fixation with 4PS and 6PS reduced L1 stress by over 47% and 25%, respectively, compared to non-fixated fractured models.
- The 6PS construct demonstrated lower stress on screws and rods during flexion and extension compared to the 4PS construct in all spinal alignment models.
Conclusions:
- The use of six pedicle screws (6PS) offers superior stress reduction on both the fractured vertebra and the spinal instrumentation compared to four pedicle screws (4PS).
- This benefit of 6PS is consistent across intact, DLS, and AIS spinal alignments, suggesting a potentially more robust fixation strategy.
- These findings support the consideration of 6PS for posterior fixation in thoracolumbar burst fractures, particularly in patients with complex spinal deformities.
