Numerical Assessment of Interspinous Spacers for Lumbar Spine

Abstract

Interspinous spacers are a minimally invasive surgical device for treating degenerative lumbar diseases, limiting spinal extension, and decreasing pressures within the disc and facets, relieving symptoms caused by lumbar spinal stenosis. This work uses the finite element method to calculate the stresses and deformations of an interspinous spacer with steel wire clamping. The cables also provide an easier way to set up the device. The reconstruction of the model was undertaken by computerized tomography, considering a person with average Mexican height (1.64 m) and a mass index grade of 2 (108 kg). The maximum movements reported in the literature were used for the range of motion. The interspinous spacer increases in a ratio of 2.7 times the stresses. Still, these stresses are generated in the prosthesis, which causes the vertebrae to be relieved since the forces and pressures are reduced. Deformations decrease by 53% with the reduction of the range of motion. Therefore, the prosthesis provides excellent stability for the vertebrae.

Keywords

• interspinous spacers
• finite element method
• spinal degenerative disease