Height-adjustable spinal fusion cage
A height-adjustable spinal fusion cage including a first end plate and a second end plate, a distal movement block fixed to be relatively movable to a dove-tail groove formed at a distal end of each of the first end plate and the second end plate, a proximal movement block fixed to be relatively movable to a dove-tail groove formed at a proximal end of each of the first end plate and the second end plate, an adjusting member rotatably fixed to the proximal movement block and screw-coupled to the distal movement block to adjust a distance between the distal movement block and the proximal movement block, and a vertical guide portion formed to be disposed at the first end plate and the second end plate and provide support for a load in a longitudinal direction or width direction of the first end plate and the second end plate.
1 . A height-adjustable spinal fusion cage comprising:
a first end plate and a second end plate configured to come in contact with adjacent vertebrae;
a distal movement block moveably coupled to a dove-tail groove formed at a distal end of each of the first end plate and the second end plate;
a proximal movement block moveably coupled to a dove-tail groove formed at a proximal end of each of the first end plate and the second end plate;
an adjusting member rotatably coupled to the proximal movement block and rotatably-coupled to the distal movement block and configured to adjust a distance between the distal movement block and the proximal movement block;
a first pin member and a second pin member each inserted through a respective pin hole in the proximal movement block and contacting a pin position portion of the adjusting member; and
a vertical guide portion configured provide support for a load in a longitudinal direction or width direction along the first end plate and the second end plate,
wherein the vertical guide portion includes a pair of first vertical guides vertically extending from the first end plate toward the second end plate and having a transverse cross-section extending in one direction, and a pair of second vertical guides comprising a slot into which a respective one of the first vertical-guides is inserted and limiting a direction of movement in which the first end plate and the second end plate approach each other or move away from each other by sliding with the pair of first vertical guides,
wherein each first vertical guide includes a first arc portion, a second arc portion spaced a predetermined distance apart from the first arc portion, and a pair of horizontal portions connecting the first arc portion and the second arc portion,
wherein each second vertical guide includes a first arc wall, a second arc wall spaced a predetermined distance apart from the first arc wall, and a pair of horizontal walls connecting the first arc wall and the second arc wall, and each slot extends in a vertical direction and is formed by the first arc wall, the second arc wall, and the pair of horizontal walls,
wherein each first arc portion of each first vertical guide comes in contact with an inner side surface of a respective first arc wall of a corresponding second vertical guide,
wherein each second arc portion of each first vertical guide comes in contact with an inner side surface of a respective second arc wall of the corresponding second vertical guide,
wherein each of the pair of horizontal portions of each first vertical guide comes in contact with inner side surfaces of respective ones of the pair of horizontal walls of the corresponding second vertical guide, and
wherein each first vertical guide includes a concave groove extending in a vertical direction and recessed in a thickness direction at a boundary between the horizontal portions and the arc portions.
2 . The height-adjustable spinal fusion cage of claim 1 , wherein the first end plate and the second end plate each include a central portion and a pair of extensions connected to opposing sides of the central portion and extending in a distal direction and a proximal direction.
3 . The height-adjustable spinal fusion cage of claim 2 , wherein the first end plate and the second end plate are each formed in an H-shape in which a portion of a distal end and a portion of a proximal end thereof are open.
4 . The height-adjustable spinal fusion cage of claim 1 , wherein the slot of each second vertical guide is configured to surround an entire outer surface of a respective one of the first vertical guides.
5 . The height-adjustable spinal fusion cage of claim 1 , wherein a marking groove is disposed along an inner surface of the first end plate and an inner surface of the second end plate, wherein the inner surfaces face each other.
6 . The height-adjustable spinal fusion cage of claim 1 , wherein a dove-tail is formed along an upper portion and a lower portion of each of the distal movement block and the proximal movement block, wherein each dove-tail is configured to be slidably coupled to a respective one of the dove-tail grooves of the first end plate and the second end plate.
7 . The height-adjustable spinal fusion cage of claim 1 , wherein an inclined groove configured to facilitate insertion of each first vertical guide is formed around each slot.