Lower back pain is normally related to the degeneration of the spinal intervertebral discs (IVD) due to the natural process
of aging. Even though conservative treatments are normally sought after, in some severe cases surgery would be the only solution to alleviate pain and prevent mechanical instability. Lumbar pack pain can be surgically treated either through arthrodesis or arthroplasty. Arthrodesis
consists of surgical immobilization or fusion of the joint, whilst arthroplasty consists of implantation of an artificial disc between the
vertebrae. The objective of this study was to analyses, using finite element method, the biomechanics of two lumbar vertebrae treated with an artificial intervertebral disc. A three dimensional model of lumbar vertebrae was created from CT datasets of L3. The model was then used to create a two0level lumbar segment with a normal healthy IVD. Another model was created where the IVD is replaced with an artificial IVD to simulate total disc replacement (TDR). The artificial IVD consists of two endplates made of metal which is separated by a polyethylene liner with dome structure on both sides to allow rotation of the endplates. The material properties of the bone were obtained from the CT datasets Hounsfield unit, and pressure was applied on the top vertebra. The results showed that the artificial IVD exerted more stress to the vertebrae, reducing the cushioning effect of an intact healthy IVD. The differences observed between the biomechanics of surgically treated and intact IVD were associated with the geometrical and surgical features of the devices.