A Biomechanical Analysis of Interspinous Spacer by 3D-Finite Element Method

Abstract

Background: Interspinous spacers are known as reliable alternatives for the treatment of various spinal disorders including lumbar spinal stenosis, facet arthrosis, internal disc disruption and so on. Many studies have been performed to investigate biomechanical and clinical features in relation to different interspinous spacers; however, little has been reported on interspinous spacer made of high polymer plastic materials. We purposed to evaluate biomechanical properties of interspinous spacer made of high polymer plastic materials in 3D-finite element models. Method: On the basis of CT scans of the lumbar spines and sacrum, 3D-finite element models, assumed in which at L4-L5 level implanted by the interspinous spacer, have been built to analyze the biomechanical properties with ANSYS WORKBENCH, under four types of loads including flexion, extension, axial compression and axial rotation. Results: The biomechanical properties of stiffness and displacement at L4-L5 segment in the models implanted with the interspinous spacer were lower than at the same segment in the models in which applied no implants under the four loads. The loads produced the same tendency at the adjacent levels including L3-L4 and L5-S in terms of stiffness as well. Conclusion: The interspinous spacer made of plastic materials provides higher biomechanical stability in the implanted and adjacent segments of the spine.

Keywords: Interspinous, spacer, spine, stiffness, deformity