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An Anesthesia, Surgery, and Harvest Method for the Evaluation of Transpedicular Screws Using an In Vivo Porcine Lumbar Spine Model
Published on: May 31, 2017
BIOMECHANICAL STUDY OF PULLOUT RESISTANCE OF CORTICAL SCREWS IN SWINE LUMBAR VERTEBRAE
Rogério Lúcio Chaves de Resende1, Jefferson Soares Leal1, Jefferson J Vilela2
1Universidade Federal de Minas Gerais (UFMG), Faculdade de Medicina, Belo Horizonte, MG, Brazil.
Introduction:
This study aimed to evaluate the mechanical resistance to pullout of the lumbar cortical bone trajectory (CBT) screw with and without transfixation of the second cortical in a biomechanical assay in swine vertebrae.
Methods:
A pullout test was performed in 16 swine vertebrae (L5 and L6) fixed with 32 CBT screws using the same protocol. Of these, 16 were inserted in a monocortical manner according to the original technique and 16 through a modified technique which included the transfixation of the second cortical bone.
Results:
The average maximum load value for pulling out the inserted screws with the modified technique including the transfixation of the second cortical bone was 140.50 Kgf (± 56.56), while in the original technique it was 95.69 Kgf (± 42.19) (p = 0.004).
Conclusion:
The biomechanical tests applied to the studied sample showed that the pullout resistance of the CBT screws inserted with the bicortical technique was, on average, 46% higher than the screws inserted according to the original monocortical technique. Level of Evidence II; Experimental study.