RESUMEN
Intervertebral disk composite model is unsatisfactory definite in biomechanical behaviour despite multiples technics used. Using histologic and histoenzymology it's possible to determinate proportions of collagen fibers in the different parts of the disk. A trustworthy finite element 3D model is proposed and tried by real experiments.
Asunto(s)
Simulación por Computador , Disco Intervertebral/anatomía & histología , Modelos Anatómicos , Fenómenos Biomecánicos , Humanos , Modelos Estadísticos , Reproducibilidad de los ResultadosRESUMEN
Optical techniques using single wavelength lasers allow precise study of the superficial displacements of deeper anatomical structures through direct mechanical pull. Two techniques have been used in this study: 1. Double exposure speckle photography. Since 1980 the relationship between the surface displacements and minimal traction applied to the transverse processes of the spine, either unilateral or bilateral, was studied in an attempt to simulate muscular action exerted at this level. 2. Computerised speckle interferometry. This allowed analysis of the deformations between the lumbar vertebrae under vertical compression, shear or torsion outside the usual anatomical planes. This preliminary study outlines the mechanical behaviour and the plasticity of the vertebral structures but has been performed on only a few anatomical specimens thus not allowing statistical analysis. This would require a larger series.
Asunto(s)
Columna Vertebral/anatomía & histología , Columna Vertebral/fisiología , Fenómenos Biomecánicos , Cadáver , Femenino , Humanos , Interferometría/métodos , Vértebras Lumbares/anatomía & histología , Vértebras Lumbares/fisiología , Persona de Mediana EdadRESUMEN
Finite element modelling of the human lumbar vertebral column employs data-processing procedures for study of the linear and nonlinear elasticity of materials such as are currently used in mechanics or in civil engineering. Thanks to developments in computer science, requiring a close collaboration between doctors and engineers, we put forward in this preliminary study a linear computerised model of the lumbar column comprising 4824 meshes and 6813 nodes. By reducing the simplificatory hypotheses and integrating new parameters, this model as developed is capable of important clinical applications in surgery and ergonomics.
Asunto(s)
Simulación por Computador , Vértebras Lumbares/anatomía & histología , Gráficos por Computador , Humanos , Vértebras Lumbares/fisiologíaRESUMEN
Opto-electronic systems utilising measurement of displacement of skin markers allows study of movement in the living subject. The authors have used this method in a kinematic study of the thoracic and lumbar spine measuring the displacement of skin markers placed over the spinous processes. It was possible to approach the physiological state of these complex movements once the apparatus had been calibrated to the correct level, and the error margins minimised. Repeated measurements confirmed the reliability of this method even if movement of the skin with respect to the bony reference points introduced some margin of error. Three dimensional displacement of the vertebrae were measured during voluntary movements of the spine demonstrating the complex geometry. Since opto-electronics are non-invasive they constitute an important advance in the study of the kinematics of the spine.