Height-adjustable spinal fusion cage
The present invention relates to a spinal fusion cage which is inserted between vertebral bodies with the lowest height and is height-adjustable in the inserted state, whereby cages having heights within a predetermined range can be replaced by a single cage. Therefore, manufacturers can reduce product groups that need to be produced, and can also reduce product stock. Further, in contrast to the conventional cages having predetermined heights at regular intervals, the height of the inventive cage can be linearly adjusted according to the distance between the vertebral bodies of a patient, and thus a surgery can be performed using the cage adjusted to an optimum height according to the patient's condition.
1. A spinal fusion cage, comprising:
a first end plate and a second end plate being in contact with adjacent vertebral bodies;
first plate slopes located at one end of each of the first end plate and the second end plate;
a distal moving block fixed to be relatively movable to the first plate slopes;
second plate slopes formed at other end of each of the first end plate and the second end plate;
a proximal moving block fixed to be relatively movable to the second plate slopes;
an adjusting member rotatably fixed to the proximal moving block and screw-coupled to the distal moving block, to adjust a distance between the distal moving block and the proximal moving block;
a first guide part formed in the first end plate to face the second end plate; and
a second guide part formed in the second end plate to face the first end plate, and constraining, by the sliding motion with the first guide part, the motion direction in which the first end plate and the second end plate come close to each other or are separated from each other,
wherein the first guide part and the second guide part support the load of the first end plate and the second end plate in the longitudinal direction or width direction, and
wherein the first end plate and the second end plate each has a bridge at the one end in the distal direction and two legs connected to the bridge extending to the other end in the proximal direction,
wherein a first window is formed in the center of the first end plate, into which a bone graft material is inserted, and
wherein a second window is formed in the center of the second end plate, into which a bone graft material is inserted.
2. The spinal fusion cage of claim 1 , wherein block sliders are formed in each of the distal moving block and the proximal moving block, and a plate sliders sliding relative to the block sliders are formed in each of the first plate slopes and the second plate slopes.
3. The spinal fusion cage of claim 2 , wherein auxiliary block sliders are arranged around the block sliders, and an auxiliary plate slider corresponding to the auxiliary block sliders are formed in each of the first end plate and the second end plate.
4. The spinal fusion cage of claim 1 , wherein the adjusting member has a screw part screw-coupled to the distal moving block at one end and has a pin space to be rotatably fixed relative to the proximal moving block at the other end, and an adjusting member pin is placed in the pin space through the proximal moving block.
5. The spinal fusion cage of claim 1 , wherein the first guide part comprises a pillar protruding toward the second end plate, and the second guide part comprises an extension wall protruding toward the first end plate to be slidable relative to the pillar.
6. The spinal fusion cage of claim 5 , wherein the first guide part has, around the pillar, a receiving part for receiving the extension wall when the first end plate and the second end plate come close to each other.
7. The spinal fusion cage of claim 6 , wherein the extension wall comprises a first wall and a second wall located in the front and back of the pillar, respectively, along the longitudinal direction of the second end plate, and a third wall connecting the first wall and the second wall to form a groove into which the pillar is inserted.
8. The spinal fusion cage of claim 7 , wherein a guide groove for guiding insertion of the pillar is formed in the first wall and the second wall.
9. The spinal fusion cage of claim 1 , wherein a first opening communicating with the first window is formed between the legs at the other end of the first end plate,
wherein a second opening communicating with the second window is formed between the legs at the other end of the second end plate,
wherein part of the proximal moving block is exposed through the first and second openings.
10. The spinal fusion cage of claim 9 , wherein first and second block grooves are formed in the proximal moving block, wherein the first block groove is exposed to the outside through the first opening, and the second block groove is exposed to the outside through the second opening.