Components of the T-Plate Anterior Fixation System are intended for use only with other components of the T-Plate Anterior Fixation System . The T-Plate is designed for an anterior approach to the lumbosacral spine below the bifurcation and is intended to stabilize a degenerated or painful vertebral joint (L5 through S1) in order to promote an arthrodesis. The patient is positioned supine on a radiolucent operating table such that AP and Lateral fluoroscopic visualization of the L5 -S1 interspace is possible. Lateral fluoroscopy is utilized in planning the anterior incision to assure that the approach is inferior enough to allow visualization of the entire disc space. A standard transperitoneal or retroperitoneal approach is made to the anterior L5-S 1 interspace. The middle sacral artery and vein are controlled and the annulus is exposed as far laterally as the local vasculature will allow. A complete discectomy is performed back to the posterior annulus. If large osteophytes are present anteriorly, these must be resected. A full posterior release of the disc space will facilitate uniform distraction of the disc space. The distraction device (Figures 1 and 2) is then placed into the disc space serially distracting to tension the lateral annular fibers. The distraction device (4200-DT11-17) is modular, allowing uniform distraction of the endplates followed by removal of the outer unit leaving the central distraction wedge centered in the disc space. The T-Plate Anterior Fixation Plate is then impacted into the disc space over the central distraction wedge. (figure 2) The central wedge is then removed through the plate.
Figure 1 Figure 2
After tapping, the vertebral body screws and interference screws are then placed securing the implant into the disc space. (Figures 3 and 4) The surgeon should decide whether the S-1 screws should be unicorticle or bicorticle screws placed laterally through the sacral ala. In the case of degenerative disc disease it is felt that only unicorticle screws in S-1 are necessary. In the case of a low grade Isthmic spondylolisthesis where the distraction has provided a passive reduction of the deformity the T-1 plate may be used but bicorticle purchase with the sacral screws is recommended. (If distraction of the spondylolisthesis does not provide passive reduction of the deformity then the T-2 plate is recommended – see surgical technique of T-2 Plate.) A standard reaming device is then passed through the anterior plate to prepare the exposed endplates for bone grafting. Autogenous bone graft or machined allograft is then placed through the plate into the disc space to facilitate the fusion. A standard closure is performed.
Figure 3 Figure 4
Removal of the T-Plate Anterior Fixation Plate is performed through the same anterior incision with the patient positioned supine on a radiolucent table. A standard transperitoneal or retroperitoneal approach is made to the anterior L5-S 1 interspace. Special care should be utilized in protecting the local vasculature in the setting of a reoperation. The plate is exposed and the Locking Plate Remover (4200-LPR1) is engaged to the locking plate and the locking plate removed. The screw heads will then be exposed and the 3.5 mm hex head screw driver (4200-SD35) is used to remove the screws. The plate holder/remover (4200-PH02) is then engaged to the T-Plate allowing the plate to be removed.