Preoperative planning and post-operative estimation of vertebroplasty using CT/CAD/CAE systems.

The aim of the work was to determine the stiffness of vertebral bodies after vertebroplasty by means of radiological examination (CT), computer-aided design (CAD) and computer-aided engineering (CAE) systems. Twenty-six patients with angiomata in vertebrae have been examined. A vertebra with pathological changes has been modeled twice, i.e., before operation and after the process of vertebral body filling with cement. The processing of CT images for the purposes of generation of 3D vertebral body models using Mimics software is also shown. In the analysis, non-homogeneous material properties of bone in the analysed areas are taken into consideration. Some problems related to the determination of non-homogeneous areas of particular material properties are discussed. FEM analyses described in the paper yielded the distributions of the stresses, strains and displacements in vertebral bodies. The stiffnesses of healthy vertebral bodies, bodies with pathological changes and bodies with bone cement injected were compared. The usefulness of the results obtained from the analyses of vertebral body stiffness for medical application in vertebroplasty was emphasized. The method presented above allows us to put forward a different approach to the problem consisting in individual examination of each patient and planning the surgery according to the case-by-case conditions. The computer-aided approach, using CT/CAD/CAE system, proposed above allows both improving the surgery performance and post-operative control of the patient's condition.