Are "Unstable" Burst Fractures Really Unstable?

Journal and index pages often block iframe embedding. This reader keeps the evidence details in Orthonotes and leaves the source page one click away.

Abstract

Conflict of interest statement: CONFLICTS OF INTEREST No potential conflict of interest relevant to this article was reported. 10. Orthop Traumatol Surg Res. 2014 Jun;100(4):379-83. doi: 10.1016/j.otsr.2014.03.016. Epub 2014 May 14. Biomechanical effects of vertebroplasty on thoracolumbar burst fracture with transpedicular fixation: a finite element model analysis. Xu G(1), Fu X(1), Du C(2), Ma J(1), Li Z(3), Ma X(4). Author information: (1)Biomechanics Labs of Orthopaedic Institute, Tianjin Hospital, 406, Jiefang Nan Street, Hexi District, 300211 Tianjin, China. (2)Department of Orthopaedics, Binzhou Medical University Hospital, 661 Yellow River Road, 256603 Binzhou, China. (3)Department of Orthopaedics, Tianjin Medical University General Hospital, 154 Anshan Street, Heping District, 300052 Tianjin, China; Department of Immunology, Tianjin Medical University, 22 Qixiangtai Road, Heping District, 300070 Tianjin, China. (4)Biomechanics Labs of Orthopaedic Institute, Tianjin Hospital, 406, Jiefang Nan Street, Hexi District, 300211 Tianjin, China. Electronic address: spiritseeker2008@gmail.com. OBJECTIVE: To investigate the biomechanical effects of augmentation of the fractured vertebrae after posterior instrumentation. METHODS: By simulating internal fixation plus augmentation with cement, eight tridimensional, anatomically detailed finite element models of the T11-L1 functional spinal junction were developed. Two kinds of models for mimicking different severity of the fracture were established according to the Denis' classification. Augmentation with cement was conducted after reduction with posterior fixation using a universal spine system. These models assumed a three-column loading configuration as follows: compression, anteflexion, extension, lateroflexion and axial rotation. Stress of the implants and spine was evaluated. RESULTS: Data showed that for severely fractured models, augmentation apparently decreased the von Mises stresses by 50% for the rods and 40% for the screws, about 40% for the inferior endplate of T11, and 50% for the superior endplate of L1 in vertical compression and other load situations. CONCLUSION: We should only apply vertebroplasty to prevent correction loss and implants failure based on the fact that it could significantly decrease stress of the instrumentations and spine when the vertebrae are severely fractured. LEVEL OF EVIDENCE: Level IV, biomechanical study. Copyright © 2014 Elsevier Masson SAS. All rights reserved. DOI: 10.1016/j.otsr.2014.03.016