SELECTIVELY EXPANDING SPINE CAGE, HYDRAULICALLY CONTROLLABLE IN THREE DIMENSIONS FOR ENHANCED SPINAL FUSION

摘要

A selectively expanding spine cage has a minimized diameter in its unexpapded state that is smaller that the diameter of the neuroforamen through which it passes in the distracted spine. The cage conformably engages between the endplates of the adjacent vertebrae to effectively distract the anterior disc space, stabilize the motion segments and eliminate pathologic spine motion. Angular deformities can be corrected, and natural curvatures restored and maintained. The cage enhances spinal arthrodesis by creating a rigi spine segment, or if filled with compressible substances, the cage can be used for motion preservation between vertebral bodies. Expanding selectively (anteriorly, along the vertical axis of the spine) rather than uniformly, the cage height increases and holds the vertebrae with fixation forces greater than adjacent bone and soft tissue failure forces in natural lordosis. Stability is thus achieved immediately, enabling patient function by eliminating painful motion.