The Biomechanical Study Of The Computer Aided Design Cage For Lumbar Interbody Fusion

Spine fusion is an important topic in spine surgery. Spinal fixation technique and the invention of lumbar fusion cage contributed significantly to the spinal fusion development.the objection of this study is to evaluate and compare the stability provided by three different lumbar fusion cage in PLIF ,one of which is computer aided designed by measuring countrymen lumbar intervertebral space 3D measurements and develop data model.Develop data model and CAD lumbar fusion cageIn this study 50 normal and degenerative lumbar were prepared For X-ray radiography of measurement, three-dimensional CT scan to get the elderly population lumbar intervertebral space 3D structure of the sample data. Data through computer imaging technology is the lumbar intervertebral space mathematical model for the Chinese people. Computer convert these data into the proposed integration of spatial data and images.With these spatial and images we design a new lumbar fusion cage which may have these attribute: Wedge structure, anatomy matching sagittal and coronal minimum design, maximizing the amount of bone design to achieve optimal stability, the largest fusion rate, the minimum rate of nerve root injury.Then produce this cage for next biomechanical experiment.Biomechanical studyIn this study ten fresh frozen human cadaveric lumbar spines(L4-S1) were used to make model of posterior laminectomy and intervertebral fusion(L4-L5) with pedicle screw fixation,On the basis of multilevel posterior pedicle screw instrumentation from L4-L5,three different lumbar fusion cages were implanted one after another.The specimens were tested in a nondestryctive manner load, it produce axial compression and the following six degrees of freedom: flexion,extension,torsion right/left and lateral bending right/left. Data were captured using CCD and an adjacent desktop computer.the stability was analyzed by Digital-Imagie-Correlation Technique.Ten fresh-frozen human cadaveric lumbar spines(L4-S1) were inspected by plain radiographs to ensure specimens the absence of structural spinal disorders,previous neoplastic disease,or spinal surgery. In addition, these images confirmed the correct anatomic sagittal and coronal aligmnment of the specimen. After intact specimen (named A group) analysis, posterior laminectomy and intervertebral fusion(L4/5) with autologous bone was performed and pedicle screw instrumentation from L4-S1.( named F1 group). After F1 group analysis, three different lumbar fusion cage were implanted once a time.Capstone was named F2 group.OIC was named F3 group. CAD-cage was named F4 group.The order of testing these nondestructive loads was randomized in each of the reconstruction stages and in each individual specimen. The result shows all group provided more stability to the specimen than intact spine in all loading modes (P<0.001). No statistical difference was found among all lumbar fusion cages group (P>0.05), though F1 group provided less staility than other lumbar fusion cage groups in flexion loading modes (P<0.05). Conclusion:The application of cage can provid more stability in PLIF.CAD-cage and other lumbar fusion cage have the same good results in spinal stability reconstruction. Selecting suitable fusion cage, can effectively simplify the surgical operation, shorten operation time, reducing surgical trauma.