Rigix plate system for anterior fixation of thoracolumbar vertebrae.

ABSTRACT

Only a few plate systems are available for anterior fixation of thoracolumbar vertebrae because of the difficulty in fastening a screw and a plate together. If the fixation is inadequate, the screws will become loose. The Rigix plate system consists of screws made of titanium alloy and a plate made of pure titanium. All screws used for internal fixation are screwed into the plate. This system permits the use of anchor screws, which facilitate exertion of force to compress the vertebral bodies together or to distract them from each other. In this study, Rigix plates were used in 24 patients (20 with burst fractures and 4 with metastatic tumors). In the 20 patients with fracture, internal fixation with a graft and a Rigix plate was performed after anterior decompression. In the four patients with malignant tumors, total spondylectomy was performed anteriorly and posteriorly, followed by implantation of a vertebral prosthesis, and then internal fixation with a Rigix plate combined posterior instrumentation with Diapson (Stryker Co., Tokyo, Japan) pedicular screws. Bone union was achieved in all patients. Neither breakage of instruments nor loosening of connections occurred in any case. In patients treated for bone metastases, the reconstructed spinal structure was able to be maintained for a long period. Of the screws used, five (5%) were not able to remain fixed as intended because they were inserted at inappropriate angles into the plate, but the fixation itself was excellent. Because of the low profile, ease of manipulation (mean instrumentation time was 25 min), and compatibility with magnetic resonance imaging, the Rigix plate is useful for anterior fixation of thoracolumbar vertebrae.