The Design, Biomechanical Evaluation And Clinical Application Of Iliac Bars Lever Reduction And Fixation System For Spondylolisthesis

Orthopaedic surgeons often face the spondylolisthesis, which is the main cause for the low back pain. Most of surgeons believe that the whole reduction of the slip vertebra is the basic of restoration of the alignment and decompression .In the history of reduction for spondylolisthesis, the first successful surgeon is Pawl Harrington in 1967, he placed the rod of Harrington system between the lamina of L1 and a bar fixed on the post iliac part. He achieved the reduction by extending rod. But through the long term follow-up, the reduction was not satisfactive, the rate of reduction is 50%~60%. In 1986, Matthiass reported the posterior lever reduction system, which reduction conducted by the lever placed at the intervertebral area. As the high risk of neurological injury, most of surgeons had not accepted this technique.Following the advocating of technique of pedicle screw, some disadvantagement of the old methods had been emerged. Matthiass and Heine first time used the pedicle screw and plate to lift the sliping vertebra, and accomplished the reduction. After the improvement of the pedicle screw, this technique had been fashioning. During the improvement of the plate once and once, a various of pedicle screw system had been using in surgery.The reducting mechanism of the pedicle screw system is through the foothold of the superior and the inferior vertebral pedicle screw, or only of the inferior vertebral pedicle screw, to lift the slip vertebra by fixing tightly the screw. However, some devices have an unefficient reduction since its structure, such as the Steffee plate, which fixation is difficult if the pedicle screws do not stand on a line; Though the Steffee plate has a better stability, its ability of opening the intervertebral space is poor. Though RF has better reduction, the...