| Objective To design a type of bionic movable prosthesis which can reconstruct the height of lumbar vertebra and preserve the motion of inter-vertebral discs after lumbar subtotal corpectomy for the treatment of the tumor, tuberculosis and fracture of lumbar vertebra. Methods To extract the lumbar CT scan data of 60 healthy male adults of our country for three dimensional reconstruction using Mimics 16.0 and measure the anatomic parameters of lumbar vertebra and inter-vertebral disc. To statistically analyze the anatomic data using IBM SPSS statistics 21and design three dimensional model of bionic artificial lumbar vertebra and disc complex with Solidworks 2013 according the statistical parameters. Then we create a photosensitive resin model of the movable prosthesis with3D-printing technology and make a preliminary assessment of its activity. Results Comparing to anterior and posterior vertebral body height, the middle height of vertebra is smaller. The median saggital and crown diameters of superior and inferior endplates are bigger than those of middle horizontal plane. The angle of upper and lower endplates with profile of lumbar vertebra is about more than 70° and there's no difference among different vertebra（P>0.05）. However, the sag depth of superior and inferior endplates exist significant difference（P<0.05）.The thickness of inter-vertebral disc obeys the law : anterior height>middle height>posterior height and there is significant difference between anterior and posterior height（P<0.05）. Bionic artificial lumbar vertebra and disc complex is composed of three parts : vertebral body parts, inter-vertebral disc parts and screws. The materials of the prosthesis are medical titanium alloys and polymer materials. Its mobile device is anti-extrusion ball-socket joint meeting axial rotation 360°, left or right side bend 10°and flexion or extension15. Conclusion Three-dimensional CT reconstruction can accurately measure anatomic parameters of the lumbar spine. Bionic artificial lumbar vertebra and disc complex can meet lumbar physiological functions to a certain extent, but there is still deficiency of excessive axial rotation and its stability, biocompatibility, corrosion resistance, wear resistance and so on need further study. |
