Vertebroplasty and kyphoplasty for the treatment of thoracic fractures in osteoporotic patients: a finite element comparative analysis

Background: Vertebral compression fractures occur in the thoracolumbar junction, causing the collapse of the vertebral body. For their treatment, vertebroplasty and kyphoplasty are used, but it is still unknown which technique is to be preferred. Methods: Finite element models of the thoracic spine were developed to evaluate the outcomes of vertebroplasty and kyphoplasty. A mild and severe collapse of T10 treated with vertebroplasty or kyphoplasty was studied. Stresses on the endplates and intradiscal pressures were extrapolated to determine the stress distribution in the adjacent structures. Results: The validation ensured a correct stiffness and a proper kinematic of each functional spinal unit. The results demonstrated that a consolidation following vertebroplasty caused slight variations of intradiscal pressures and stresses. If a kyphoplasty was performed after a mild collapse of the vertebral body, a 25% stress reduction on endplates was found. In cases of severe collapse, when a partial height restoration was achieved, a 15% stress reduction was obtained, while with a full recovery of the anterior wall of the collapsed vertebra, there was a further reduction of 40%. Conclusions: To reduce the stresses on the adjacent endplates and the risk of fracture, the results suggest a kyphoplasty is to be preferred, trying to restore the initial vertebral body height. Keywords: Finite element method, Kyphoplasty, Vertebral compression fractures, Vertebroplasty