Biomechanical comparison of posterior short-segment fixation with or without intermediate screws for thoracolumbar burst fractures under normal and osteoporotic conditions: a finite element analysis
10.31616/asj.2025.0442
- Author:
Cheng XU
;
XiangMing ZHANG
;
Hong Jian CAO
;
Chao SHEN
;
Feng GE
;
Xuedong BAI
;
Chao ZHANG
- Publication Type:Basic Study
- From:Asian Spine Journal
2026;20(2):223-231
- CountryRepublic of Korea
- Language:English
-
Abstract:
Methods:Six finite element models of T12 burst fractures were developed to simulate short-segment stabilization under normal or osteoporotic bone conditions, with/without augmentation screws at the fractured vertebra. Spinal stiffness, implant stresses, and axial displacement/micromotion of the bony defect were measured and compared under mechanical loading.
Results:Osteoporotic models exhibited a greater range of motion (ROM) than normal bone. All six-screw constructs reduced ROM across all motions compared with traditional four-screw models. Osteoporotic fracture models gained greater benefit from intermediate screw augmentation at the fracture vertebra, which also lowered axial displacement/micromotion. In six-screw models, rod stress increased while pedicle screw stress decreased. Intermediate screws at fractured vertebrae produced similar changes in stress distribution across all fixation models, regardless of bone quality.
Conclusions:Our findings may facilitate implant selection for osteoporotic burst fractures, supporting the use of more rigid fixation sixscrew constructs to reduce the risk of mechanical failure and postoperative re-collapse.
