Biomechanical modelling of the intervertebral disc of the human lumbar spine - the problem current state

Pain in the lumbar region or other part of the spine is the important reason for the decline of the life quality and the population efficiency, which directly affects the economy as a whole. Every year, a money huge amount is allocated in health care to prevent this disease. The causes of this pain are very diverse: muscle spasms, kidney diseases, the vertebrae osteoporosis, herniated discs and etc. It is proved that the intervertebral disc L4-L5 is the most vulnerable part of the lumbar spine, so the biomechanical modelling problem of the intervertebral disc is considered important and relevant in the modern world. A comprehensive analysis of the literature for period 2006-2018 is performed. The work aim is to consider various approaches to modelling of the intervertebral symphysis, strong and weak parts of models and methods of obtaining the disc geometric shape. In article, the parameters are analyzed: the constitutive relations choice, the use of a set of images of computerized tomography or magnetic resonance imaging, the geometric shape of any component of the model, the finite element type, software packages (choice of stress-strain state calculation and obtaining a geometric shape from a set of computed tomography or magnetic resonance imaging), the age and gender impact on the overall model. Detailed analysis of each component of the intervertebral cartilage: nucleus pulposus, fibrous ring (matrix and elastic fibers), cartilage endplate and bone endplate is performed.