Augmentation of pedicle screw fixation with calcium phosphate cement

Abstract

To determine whether a biodegradable calcium phosphate cement (CPC) provides significant augmentation of pedicle screw fixation or not, an in vitro biomechanical study was carried out to evaluate the biomechanical effect of CPC in the restoration and augmentation of pedicle screw fixation. Axial pullout test and cyclic bending resistance test were employed in the experiment, and polymethylmethacrylate (PMMA) was chosen as control. The results demonstrate that the pullout strengths following CPC restoration and augmentation are 74%greater on an average than those of the control group, but less than those of PMMA restoration group and augmentation group respectively (increased by 126%versus control). In cyclic bending resistance test, the CPC augmented screws are found to withstand a greater number of cycles or greater loading with less displacement before loosening, but the augmentation effect of PMMA is greater than that of CPC.

Keywords

calcium phosphates / bone cement / bone nails / biomechanics

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