Lateral spondylolisthesis reduction cage
View Patent ↗An intervertebral fusion device comprising inferior and superior fusion cage devices that provide an ability to correct spondylolisthesis via in-situ adjustment.
1. An intervertebral fusion device for correcting spondylolisthesis in a patient, comprising:
a) an upper cage having an anterior wall, a posterior wall, a lower surface, and a proximal wall and a distal wall connecting the anterior and posterior walls, and a throughole present at the upper edge of the proximal wall for receiving a bone screw,
b) a lower cage having an anterior wall, a posterior wall, an upper surface, and a proximal wall and a distal wall connecting the anterior and posterior walls, and a lower surface for contacting a lower vertebral body, and a throughole present at the lower edge of the proximal wall for receiving a bone screw,
wherein the proximal wall of the upper cage has a lower through-hole adapted for receiving a fixation device and wherein the proximal wall of the lower cage has an upper through-hole adapted for receiving a fixation device, and
c) a fixation device disposed in each respective through-hole,
d) a bone screw disposed in each respective throughole,
wherein the lower surface of the upper cage slidingly mates with the upper surface of the lower cage to allow linear anterior-posterior relative movement of the cages,
wherein the lower surface of the upper cage and the upper surface of the lower cage have matching ratchet teeth.