PT  - JOURNAL ARTICLE
AU  - Limthongkul, Worawat
AU  - Wannaratsiri, Nutthee
AU  - Sukjamsri, Chamaiporn
AU  - Benyajati, Chi-na
AU  - Limthongkul, Pimpa
AU  - Tanasansomboon, Teerachat
AU  - Yingsakmongkol, Wicharn
AU  - Singhatanadgige, Weerasak
TI  - Biomechanical Comparison Between Posterior Long-Segment Fixation, Short-Segment Fixation, and Short-Segment Fixation With Intermediate Screws for the Treatment of Thoracolumbar Burst Fracture: A Finite Element Analysis
AID  - 10.14444/8441
DP  - 2023 Jun 01
TA  - International Journal of Spine Surgery
PG  - 442--448
VI  - 17
IP  - 3
4099  - https://www.ijssurgery.com/content/17/3/442.short
4100  - https://www.ijssurgery.com/content/17/3/442.full
SO  - Int J Spine Surg2023 Jun 01; 17
AB  - Background Posterior long-segment (LS) fixation, short-segment (SS) fixation, and short segment fixation with intermediate screws (SI) have shown good outcomes for the treatment of thoracolumbar burst fractures. However, limited data compared the biomechanical properties between LS fixation and SI. The purpose of this study was to compare the von Mises stresses on the pedicular screw system and bone between posterior LS fixation, SS fixation, and SI for the treatment of thoracolumbar burst fracture.Materials and Methods The finite element model of thoracolumbar spines from T11 to L3 was created based on the computed tomography image of a patient with a burst fracture of the L1 vertebral body. The models of pedicular screws, rods, and locking nuts were constructed based on information from the manufacturer. Three models with different fixation configurations—that is, LS, SS, and SI—were established. The axial load was applied to the superior surface of the model. The inferior surface was fixed. The stress on each screw, rod, and vertebral body was analyzed.Results The motion of the spine in SS (0.5 mm) and SI (0.9 mm) was higher than in LS (0.2 mm). In all models, the lowest pedicle screws are the most stressed. The stress along the connecting rods was comparable between SI and LS (50 MPa). At the fracture level, stress was found at the pedicles and vertebral bodies in SI. There was relatively little stress around the fractured vertebral body in LS and SS.Conclusions Posterior SI preserves more spinal motion than the LS. In addition, it provides favorable biomechanical properties than the SS. The stress that occurred around the pedicle screws in SI was the least among the 3 constructs, which might reduce complications such as implant failure. SI produces more stress in the fractured vertebral body than LS and SS, which could potentially aid in bone healing according to the Wolff law.Clinical Relevance SI has proved to be a biomechanically favorable construct and helps preserve the spinal motion segment. It could be an alternative surgical option for treating patients who present with thoracolumbar burst fractures.Level of Evidence 5.