The Development Of New Posterior Dynamic Spinal Internal Fixation Device And The Research Of It's Preliminary Biomechanics

Partâ… The new posterior dynamic internal fixation devices'development of abdominal vertebraObjective To design a new posterior dynamic internal fixation device which is simple, cheap, and suitable for low back pain caused by the lumbar instability and discogenic pain. Method Apparatus are composed by the end of the one-sided concave ball and socket of the pedicle screws, lateral mass of vertebrae screws with tail are flat, flexible connecting rod and the sleeve composition. Lateral mass of vertebrae screws and flexibility of metal connecting rod are made of medical titanium alloy , and the sleeve is made of the medical supermolecular weight polyethylene. Screw diameter is 6.0mm, and length is 40mm. Flexible connecting rod diameter is 2.0mm. The sleeve's outside diameter is 9.5mm and inner diameter is 2.0mm. Results To preliminary design a set of posterior dynamic fixation internal devices in lumbar posterior pedicle screw through lateral mass of vertebrae. Conclusion This new posterior dynamic internal fixation device is reasonable in desiging ,easy to use, and consistent with the concept of dynamic internal fixation.Partâ…¡The initial bio-mechanical test of new posterior dynamic internal fixation devicesObjective By biomechanical experiments to test the new dynamic internal fixation device in the lumbar dynamic stability, load bearing area of performance. To provide a further improvement and scientific basis for clinical application. Method There were 3 lumbar spine specimens of adult fresh cadaver(including 7 FSU), divided into 4 groups: normal, unstable, dynamic internal fixation, rigid internal fixation. To test segment of vertebral bodies in the four states: flexion after the extension, left / right lateral bending ,and left / right axial rotation, six degrees of freedom on the range of motion (ROM). The datas were used statistical analysis software SPSS16.0. Results Injury unstable state ROM segment was significantly higher than other states (P <0.05). Two ways of New dynamic within a fixed and rigid internal fixation after fixation, segmental ROM was less than the full samples (P<0.05). New dynamic segments within a fixed ROM after the firm was greater than rigid internal fixation (P <0.05). Conclusion This new dynamic fixation device on the fixed segment has good stabilizing effect, while retaining a fixed part of the ROM segments.