Patent Description:
The vertebral column includes <NUM> to <NUM> vertebrae and intervertebral disks, which are simply called disks, and is the central part of the body that connects the skull at the top and the pelvis at the bottom.

The vertebral column is composed of <NUM> cervical vertebrae, <NUM> thoracic vertebrae, <NUM> lumbar vertebrae, <NUM> sacral vertebrae (sacrum), and <NUM> to <NUM> coccygeal vertebrae (coccyx). In adults, the five sacral vertebrae fuse into one sacrum, and the three to five coccygeal vertebrae fuse into one coccyx.

Intervertebral fusion (interbody fusion) is a method of treating serious spinal diseases that last for a long time. In interbody fusion surgery, an intervertebral disk (disk) is removed, and a cage is inserted as a substitute between adjacent vertebral bodies to join the adjacent vertebral bodies together.

Interbody fusion methods for the lumbar spine may be classified, depending on the insertion direction of a cage, into posterior lumbar interbody fusion (PLIF), transforaminal lumbar interbody fusion (TLIF), lateral lumbar interbody fusion (LLIF), oblique lumbar interbody fusion (OLIF), anterior lumbar interbody fusion (ALIF), etc..

Posterior lumbar interbody fusion (PLIF) is a method of making an incision along the midline of the lumbar spine to entirely expose a vertebra, removing a posterior portion of the vertebra, removing a disk, and inserting PLIF cages.

Posterior lumbar interbody fusion (PLIF) is the oldest method among lumbar interbody fusion methods, and is necessary when fusing two or three vertebrae together. However, posterior lumbar interbody fusion (PLIF) has disadvantages such as a high possibility of adhesions at the nerves, ligaments, and muscles due to surgical procedures, a long recovery time due to a large incision area, and serious sequelae in some patients.

PLIF cages, a pair of small cages configured to be arranged at the left and right sides, are smallest among all the cages used for interbody fusion.

Transforaminal lumbar interbody fusion (TLIF) is a surgical method in which small incisions are made along both sides of a spine muscle to minimally expose the body of a vertebra, and then while removing a portion of the vertebra to expose a neural foramen, a TLIF cage is inserted instead of a disk. This surgical technique is advantageous in terms of less bleeding and a short operation time and is suitable for one joint, but PLIF is required when treating multiple sites. Most TLIF cages are arc-shaped, and thus the convex portion of a TLIF cage is oriented toward the abdomen by inserting and rotating the TLIF cage between vertebral bodies. TLIF cages are larger than PLIF cages, but the supporting areas of TLIF cages are smaller than those of LLIF cages or ALIF cages, which will be mentioned later.

Anterior lumbar interbody fusion (ALIF) has several advantages, such as quick recovery from surgery and a low possibility of adhesions. However, ALIF requires a highly advanced skill in making an incision in the anterior (abdomen) and accessing the spine while dislodging the internal organs. ALIF cages have an advantage of having the largest support areas among all interbody fusion cages.

As such an ALIF cage, a self-supporting cage (integrated cage) having holes through which screws can be inserted and fixed to vertebral bodies to prevent separation of the cage after surgery is disclosed (<CIT>).

In addition, <CIT> and <CIT> disclose height-adjustable, self-supporting ALIF cages. In <CIT>, a vertical ratchet <NUM> is used for height adjustment. That, angle adjustment is substantially performed instead of height adjustment. <CIT> discloses height adjustment but has problems such as a very complicated structure and difficulty in manufacturing.

An objective of the present disclosure for solving the problems described above is to provide an intervertebral fusion cage, which is insertable between vertebral bodies in a lowest state, adjustable in height in the inserted state, capably of stably supporting the movement of a pair of end plates, and particularly capably of improving fixation owing to bone screws inserted through the end plates.

To achieve the objective, the present disclosure provides an intervertebral fusion cage including: a first end plate and a second end plate, which are configured to be in contact with adjacent vertebral bodies; a distal movable block fixed in a state in which the distal movable block is movable relative to a plate slope portion formed on an end of the first end plate and a plate slope portion formed on an end of the second end plate; a proximal movable block fixed in a state in which the proximal movable block is movable relative to a plate slope portion formed on another end of the first end plate and a plate slope portion formed on another end of the second end plate; an adjustment member rotatably fixed to the proximal movable block and screwed to the distal movable block to adjust a distance between the distal movable block and the proximal movable block; a first guide portion formed on the first end plate toward the second end plate; a second guide portion formed on the second end plate toward the first end plate to limit, by sliding between the first guide portion and the second guide portion, a movement direction in which the first end plate and the second end plate are moved close to or away from each other; a bone screw configured to be inserted into bone screw holes formed in the first end plate and the second end plate; and a locking member configured to be fastened to the proximal movable block to prevent separation of the bone screw, wherein the first guide portion and the second guide portion support a load in a length or width direction of the first end plate and the second end plate.

Block sliders are formed on the distal movable block and the proximal movable block, and plate sliders slidable with respect to the block sliders are formed on the plate slope portions.

In addition, the block sliders of the distal movable block are arranged on both sides of block slope portions corresponding to the plate slope portions, auxiliary block sliders are arranged on outer sides of the block sliders, and auxiliary plate sliders corresponding to the auxiliary block sliders are formed on the first end plate and the second end plate.

In addition, reinforcing slope portions are formed on center portions of the block slope portions, and reinforcing slope portion seats corresponding to the reinforcing slope portions are formed on the first and second end plates.

In addition, the adjustment member includes: a threaded portion formed on an end thereof and configured to be screwed to the distal movable block; and an adjustment member support surface formed on another end thereof and rotatable at a given position with respect to the proximal movable block.

In addition, the first guide portion includes a pillar protruding toward the second end plate, and the second guide portion includes an extension wall protruding toward the first end plate and slidable with respect to the pillar.

In addition, an accommodation portion is formed near the pillar to receive the extension wall when the first end plate and the second end plate are moved close to each other.

In addition, a guide recess is formed in the extension wall to guide insertion of the pillar.

In addition, a clearance cut portion is formed on the extension wall to prevent interference with the bone screw.

In addition, the locking member includes a locking plate configured to cover the bone screw and a locking bolt configured to be fixed to the proximal movable block through the locking plate, and a locking-bolt coupling portion is formed on the proximal movable block such that the locking bolt is coupled to a front end of the adjustment member.

In addition, a locking protrusion protruding toward the bone screw is formed on a rear end of the locking plate.

In addition, when the locking bolt is coupled, the locking bolt comes into contact with the adjustment member and pushes the adjustment member.

In addition, an anchor portion having no screw thread is formed on a distal end portion of the bone screw.

In addition, the anchor portion includes an anchor groove extending in a length direction of the bone screw.

In addition, the anchor portion includes an anchor protrusion protruding in radial directions.

According to the present disclosure, cages having heights within a given range may be replaced with one cage. Therefore, manufacturers may reduce the number of product groups and the amount of inventory. In addition, because the height of the cage of the present disclosure is linearly adjustable according to the distance between vertebral bodies of patients unlike conventional intervertebral fusion cages having heights preset at predetermined intervals, surgery may be performed at an optimal height according to the conditions of patients.

In addition, because the cage is insertable in a lowest state, it is not necessary to fabricate additional test inserts according to a proper intervertebral spacing, and surgeons are not needed to sequentially insert a plurality of inserts for securing an insertion space. The invention is as defined in independent claim <NUM>.

Hereinafter, preferred embodiments of the present disclosure will be described with reference to the accompanying drawings. In the drawings, the same elements may be denoted with the same reference numerals even though the elements are shown in different drawings, and detailed descriptions related to well-known functions or configurations will be ruled out in order not to unnecessarily obscure subject matters of the present disclosure.

<FIG> entirely illustrate an intervertebral fusion cage <NUM> according to embodiments, and <FIG> illustrate elements of the intervertebral fusion cage <NUM>.

The intervertebral fusion cage <NUM> generally includes: a first end plate <NUM> and a second end plate <NUM>, which face each other in a vertical direction; a distal movable block <NUM> and a proximal movable block <NUM>, which are arranged between the first end plate <NUM> and the second end plate <NUM> and movable according to the distance between the first end plate <NUM> and the second end plate <NUM>; an adjustment member <NUM>, which is connected to the distal movable block <NUM> through the proximal movable block <NUM>; bone screws <NUM>, which are inserted into the first end plate <NUM> and the second end plate <NUM> for being fixed to vertebral bodies; and a locking member configured to prevent separation of the bone screws <NUM>.

The first end plate <NUM> and the second end plate <NUM> include a first plate body <NUM> and a second plate body <NUM>, which have tooth-shaped protrusions on surfaces to be brought into contact with vertebral bodies. The tooth-shaped protrusions are formed to prevent separation from vertebral bodies and may be variously modified. In addition, a first window <NUM> and a second window <NUM> may be respectively formed in a center portion of the first plate body <NUM> and a center portion of the second plate body <NUM> such that a bone graft may be inserted therethrough.

In addition, as shown in <FIG> and <FIG>, a proximal movable block seat <NUM> is formed in the length direction of the first plate body <NUM> toward the center of the body, and a distal movable block seat <NUM> is formed in the length direction of the first plate body <NUM> away from the center of the body. A plate slope portion <NUM> extends from the proximal movable block seat <NUM>, and a pair of plate sliders <NUM> facing each other are formed on both sides of the plate slope portion <NUM>. In addition, bone screw holes <NUM> are formed on outer sides of the plate sliders <NUM>. The bone screw holes <NUM> are penetration holes into which the bone screws <NUM> may be inserted, and guide surfaces <NUM> for guiding the bone screws <NUM> may be formed on entrance sides of the bone screw holes <NUM>. In addition, plate slope portions <NUM> are formed around the distal movable block seat <NUM>. The plate slope portions <NUM> are formed on both ends of the distal movable block seat <NUM>, and plate sliders <NUM> are respectively formed on outer sides of the plate slope portions <NUM>. In addition, auxiliary plate sliders <NUM> facing the plate sliders <NUM> may be formed on outer sides of the plate sliders <NUM>. The plate sliders <NUM> proximal to the center of the body and the plate sliders <NUM> distal to the center of the body are sloped are sloped in a manner such that the plate sliders <NUM> and the plate sliders <NUM> approach the center of the first plate body <NUM> as it goes away from a surface of the first plate body <NUM> in the thickness direction of the first plate body <NUM>.

In addition, a reinforcing slope portion seat <NUM> extends from the distal movable block seat <NUM>. A reinforcing slope portion <NUM>, which is described later, may be positioned on the reinforcing slope portion seat <NUM>, and when the distal movable block <NUM> is moved, the reinforcing slope portion <NUM> may not interfere with the first plate body <NUM> owing to the reinforcing slope portion seat <NUM>.

Similarly, as shown in <FIG> and <FIG>, a proximal movable block seat <NUM> is formed in the length direction of the second plate body <NUM> toward the center of the body, and a distal movable block seat <NUM> is formed in the length direction of the second plate body <NUM> away from the center of the body. A plate slope portion <NUM> extends from the proximal movable block seat <NUM>, and a pair of plate sliders <NUM> facing each other are formed on both sides of the plate slope portion <NUM>. In addition, bone screw holes <NUM> are formed in outer sides of the plate sliders <NUM>. The bone screw holes <NUM> are penetration holes into which the bone screws <NUM> may be inserted, and guide surfaces <NUM> for guiding the bone screws <NUM> may be formed on entrance sides of the bone screw holes <NUM>. In addition, plate slope portions <NUM> are formed around the distal movable block seat <NUM>. The plate slope portions <NUM> are formed on both ends of the distal movable block seat <NUM>, and plate sliders <NUM> are respectively formed on outer sides of the plate slope portions <NUM>. In addition, auxiliary plate sliders <NUM> facing the plate sliders <NUM> are formed on outer sides of the plate sliders <NUM>. The plate sliders <NUM> proximal the center of the body and the plate sliders <NUM> distal to the center of the body are sloped in a manner such that the plate sliders <NUM> and the plate sliders <NUM> approach the center of the second plate body <NUM> as it goes away from a surface of the second plate body <NUM> in the thickness direction of the second plate body <NUM>.

In addition, a reinforcing slope portion seat <NUM> extends from the distal movable block seat <NUM>. A reinforcing slope portion <NUM>, which is described later, may be positioned on the reinforcing slope portion seat <NUM>, and when the distal movable block <NUM> is moved, the reinforcing slope portion <NUM> may not interfere with the second plate body <NUM> owing to the reinforcing slope portion seat <NUM>.

As shown in <FIG> and <FIG>, block slope portions <NUM> are formed on the proximal movable block <NUM> around a proximal connection tube body <NUM> having an adjustment member hole <NUM> into which the adjustment member <NUM> is to be inserted and supported. Block sliders <NUM>, which are to be slidably coupled to the plate sliders <NUM> and <NUM> formed on the first and second end plates <NUM> and <NUM>, are arranged on both sides of the block slope portions <NUM>. The adjustment member hole <NUM> includes: a support portion <NUM> that is to be in contact with the adjustment member <NUM> for supporting the adjustment member <NUM>; and a support jaw <NUM> formed on a distal end side of the support portion <NUM> to prevent separation of the adjustment member <NUM>. In addition, pinholes <NUM> are formed in lateral portions of the proximal movable block <NUM> to prevent the adjustment member <NUM> from being separated toward the center of the body. In addition, tool seats <NUM> are formed in the lateral portions of the proximal movable block <NUM> to fix the intervertebral fusion cage <NUM> using a tool. In addition, a locking-bolt coupling portion <NUM>, to which a locking bolt <NUM> (described later) is to be coupled, is formed in a region that is more proximal than a region in which the adjustment member <NUM> is to be inserted.

As shown in <FIG> and <FIG>, a distal connection tube body <NUM> having a movable block thread portion <NUM> to which the adjustment member <NUM> is to be screwed is formed on a center portion of the distal movable block <NUM>, and wing portions <NUM> are provided on both sides of the distal connection tube body <NUM>. Block slope portions <NUM> are formed on the wing portions <NUM>, and block sliders <NUM> are arranged on both sides of the wing portions <NUM>. Auxiliary block sliders <NUM> are formed on outer sides of the block sliders <NUM>. The block sliders <NUM> and the auxiliary block sliders <NUM> are configured to be slidably coupled to the plate sliders <NUM> and <NUM> and the auxiliary plate sliders <NUM> and <NUM> of the first and second end plates <NUM> and <NUM>, respectively.

The distal movable block <NUM> has a distal wall <NUM> for ease of insertion between vertebral bodies, and the distal wall <NUM> is formed in one piece with the block slope portions <NUM>. Furthermore, in a lowest state, the distal wall <NUM> is in contact with an end portion of the first end plate <NUM> and an end portion of the second end plate <NUM>, forming an insertion portion as a whole. In particular, distal bent surfaces <NUM> are formed on both sides of the distal wall <NUM>, further facilitating insertion.

Reinforcing slope portions <NUM> are formed in a center region of the distal movable block <NUM> to reinforce the distal movable block <NUM> when the block sliders <NUM> and the auxiliary block sliders <NUM> support a load. As described above, the reinforcing slope portions <NUM> are stably positioned while being inserted into the reinforcing slope portion seats <NUM> and <NUM> of the first end plate <NUM> and the second end plate <NUM>.

The distal movable block <NUM> and the proximal movable block <NUM> have a substantially wedge-shaped structure, and are configured to push or support the first end plate <NUM> and the second end plate <NUM> when lifting or lowering the first end plate <NUM> and the second end plate <NUM>.

The adjustment member <NUM> may have a substantially bolt shape as shown in <FIG>. That is, the adjustment member <NUM> has an adjustment member support surface <NUM> and an adjustment thread portion <NUM>. A connection portion <NUM> may be formed between the adjustment member support surface <NUM> and the adjustment thread portion <NUM>. A pin seat <NUM> may be formed on a proximal side of the adjustment member support surface <NUM>, and a tool recess <NUM> may be formed in a center portion of the pin seat <NUM> for driving the adjustment member <NUM>. Although the adjustment thread portion <NUM> is a male screw portion, a detailed shape thereof is not shown in the drawings.

The adjustment member support surface <NUM> is rotatably supported in contact with the support portion <NUM> of the distal movable block <NUM>. The adjustment thread portion <NUM> is screwed to the movable block thread portion <NUM> of the adjustment member <NUM>. Although the movable block thread portion <NUM> is a female screw portion, a detailed shape thereof is not shown in the drawings. In addition, because a distal clearance surface of the adjustment member support surface <NUM> is brought into contact with the support jaw <NUM>, the adjustment member <NUM> is not separated from the distal movable block <NUM> in a distal direction. In addition, a pin member <NUM> is inserted into the pin seat <NUM> and positioned in the pin seat <NUM> such that the adjustment member <NUM> may not be separated from the distal movable block <NUM> in a proximal direction.

Therefore, the adjustment member <NUM> is rotatable at a given internal position of the adjustment member <NUM>.

A pair of pillars <NUM> are formed on both sides of the first plate body <NUM> in a thickness direction of the first plate body <NUM>, that is, in a direction toward the second end plate <NUM>. In addition, accommodation portions <NUM> for receiving extension walls <NUM> (described later) are formed near the pillars <NUM>. In addition, the extension walls <NUM> are formed on both sides of the second plate body <NUM> in a thickness direction, that is, in a direction toward the first end plate <NUM>, and grooves <NUM> for receiving and guiding the pillars <NUM> are formed in inner sides of the extension walls <NUM>. Therefore, as the pillars <NUM> are inserted into the grooves <NUM> and vertically moved in the grooves <NUM>, the first end plate <NUM> and the second end plate <NUM> may be moved toward or away from each other in a restricted state. Here, the pillars <NUM> and the extension walls <NUM> correspond to a first guide portion and a second guide portion. The first guide portion and the second guide portion have a function of supporting a load or torsion in the length or width direction of the first end plate <NUM> and the second end plate <NUM>.

In addition, when viewed from the top, the extension walls <NUM> have a substantially U-shape to surround the pillars <NUM>. In addition, clearance cut portions <NUM> are formed on the extension walls <NUM> such that when the bone screws <NUM> are inserted in a narrow space, the insertion of the bone screws <NUM> may not be obstructed by the extension walls <NUM>
The locking member may include: a locking plate <NUM> configured to cover the bone screws <NUM>; and the locking bolt <NUM> configured to be fixed to the proximal movable block <NUM> through the locking plate <NUM>.

As shown in <FIG> and <FIG>, the locking plate <NUM> includes a locking plate body <NUM> shaped like a plate, and cover portions <NUM> extending from both sides of the locking plate body <NUM> may be slightly curved to cover the locking bolt <NUM>. In addition, locking protrusions <NUM> may be formed on rear ends of the cover portions <NUM>, that is, distal sides of the cover portions <NUM>. The locking protrusions <NUM> may have a substantially hemispherical shape and may be variously modified. Because the distance between the first end plate <NUM> and the second end plate <NUM> is variable, the distance between screw heads <NUM> of the bone screws <NUM> inserted into the first end plate <NUM> and the second end plate <NUM> is also variable. Therefore, it is preferable that the locking protrusions <NUM> be formed on the cover portions <NUM> to cover the screw heads <NUM> while the distance between the first end plate <NUM> and the second end plate <NUM> varies from a minimal value to a maximum value.

In addition, a locking bolt hole <NUM> is formed in a center portion of the locking plate body <NUM> to receive a portion of the locking bolt <NUM>. In addition, a locking bolt seat <NUM> may be formed around the locking bolt hole <NUM> to support a rear end of a locking bolt head <NUM> of the locking bolt <NUM>. In addition, the locking-bolt coupling portion <NUM> is formed on the proximal movable block <NUM> such that the locking bolt <NUM> may be coupled to a front end of the adjustment member <NUM> through the locking-bolt coupling portion <NUM>. Although the locking-bolt coupling portion <NUM> is a female screw portion, a detailed shape thereof is not shown in the drawings.

The locking bolt <NUM> includes: the locking bolt head <NUM> configured to be placed on the locking bolt seat <NUM>; a locking thread portion <NUM> on which a thread is formed for coupling with the locking-bolt coupling portion <NUM>; and a tool recess <NUM> for coupling with a tool. In particular, a ring groove may be formed in the locking bolt <NUM>, and a fixing ring <NUM> may be fitted to the ring groove to prevent separation of the locking bolt <NUM> from the locking plate <NUM>.

When the locking bolt <NUM> is fastened to the proximal movable block <NUM>, the locking bolt <NUM> is brought into contact with the adjustment member <NUM>, and thus the locking bolt <NUM> pushes the adjustment member <NUM>. At this time, friction occurs between the locking bolt <NUM> and the adjustment member <NUM>. As a result, friction increases in a threaded region of the adjustment member <NUM> such that even when a load, particularly a repetitive load, is applied to the first end plate <NUM> and the second end plate <NUM>, the adjustment member <NUM> may not be unfastened.

Next, the bone screws <NUM>, and bone screws <NUM>, <NUM> and <NUM>, which are modification examples of the bone screws <NUM>, will be described according to embodiments with reference to <FIG>.

The bone screw <NUM> shown in <FIG> may be a bone screw of the related art. The bone screw <NUM> includes: a screw head <NUM> configured to limit the degree of insertion of the bone screw <NUM> when the bone screw <NUM> is inserted into the bone screw holes <NUM> and <NUM>; a tool recess <NUM> formed in the screw head <NUM> for receiving a tool; and a threaded portion <NUM> formed in one piece with the screw head <NUM> and configured to be inserted into a vertebral body. The threaded portion <NUM> includes a double-lead thread and a single-lead thread for both the cancellous bone and the cortical bone.

The bone screw <NUM> shown in <FIG> includes: a screw head <NUM>; a tool recess <NUM> formed in the screw head <NUM>; and a vertebral body insertion portion, which is formed in one piece with the screw head <NUM> and has a proximal threaded portion <NUM> and a distal anchor portion <NUM>.

A separate tool, such as an awl, is required to set an initial direction for surgery with an ALIF cage. In addition, because the fixing force of a screw fastened to cancellous bone is not great, a screw thread may often be meaningless for cancellous bone. Therefore, the bone screw <NUM> includes the anchor portion <NUM> formed on a distal end portion of the threaded portion <NUM>. In this case, a separate tool is not necessary for setting an initial direction, and discomfort caused by screwing may be reduced because insertion is carried out by hitting.

The anchor part <NUM> of the bone screw <NUM> has a nail-like shape in which only an end portion of a shank has a conical tip for ease of insertion.

The bone screw <NUM> shown in <FIG> includes: a screw head <NUM>, a tool recess <NUM> formed in the screw head <NUM>; and a vertebral body insertion portion, which is formed in one piece with the screw head <NUM> and has a proximal threaded portion <NUM> and a distal anchor portion <NUM>. In addition, an anchor groove <NUM> is formed in the anchor portion <NUM>.

The anchor groove <NUM> is formed in the length direction of the bone screw <NUM> to increase anchoring force by increasing a contact area with bone.

The bone screw <NUM> shown in <FIG> includes: a screw head <NUM>; a tool recess <NUM> formed in the screw head <NUM>; and a vertebral body insertion portion, which is formed in one piece with the screw head <NUM> and has a proximal threaded portion <NUM> and a distal anchor portion <NUM>. In addition, an anchor groove <NUM> is formed in the anchor portion <NUM>, and an anchor protrusion <NUM> protruding in radial directions is formed on the anchor portion <NUM>.

The anchor groove <NUM> is formed in the length direction of the bone screw <NUM> to increase anchoring force by increasing a contact area with bone, and along with this, the anchor protrusion <NUM> prevents separation of the bone screw <NUM>.

The intervertebral fusion cage <NUM> is configured as described above, and a surgery method (not claimed) using the intervertebral fusion cage <NUM> will now be described.

First, a surgical path to vertebral bodies is secured using surgical tools, and a disk is removed. Then, in a state in which the intervertebral fusion cage <NUM> is held by a cage holder (not shown), the intervertebral fusion cage <NUM> is inserted between the vertebral bodies from which the disk has been removed.

Thereafter, the proximal movable block <NUM> and the distal movable block <NUM> are moved close to each other by inserting a tool such as a screwdriver into the tool recess <NUM> of the adjustment member <NUM> and rotating the tool in one direction, and thus the first end plate <NUM> and the second end plate <NUM> are moved apart from each other.

Thereafter, the bone screws <NUM> are inserted into and fixed to the bone screw holes <NUM> and <NUM> of the first end plate <NUM> and the second end plate <NUM>. In this case, for the insertion of the bone screws <NUM>, holes are initially formed using a tool called an awl, and the holes are deepened with a drill. Thereafter, screw threads slightly smaller than the screw threads of the bone screws <NUM> are formed with a tool called a tapper to form paths for the screw threads of the bone screws <NUM>, and then the bone screws <NUM> are inserted by rotating the bone screws <NUM> with a tool such as a screwdriver. The formation of the screw threads by the tapper may be omitted.

However, the bone screws <NUM>, <NUM>, and <NUM> shown in <FIG> do not require tools such as an awl, a drill, and a tapper, but the initial orientation and insertion of the bone screws <NUM>, <NUM>, and <NUM> are performed by hitting with a tool such as a mallet. Then, the threaded portions of the bone screws <NUM>, <NUM>, and <NUM> are inserted by rotating the bone screws <NUM>, <NUM>, and <NUM> with a tool such as a screwdriver.

After the bone screws <NUM>, <NUM>, <NUM>, or <NUM> are inserted as described above, the locking plate <NUM> is moved close to the proximal movable block <NUM>, and the locking bolt <NUM> is coupled to the locking-bolt coupling portion <NUM> of the proximal movable block <NUM> by rotating the locking bolt <NUM> with a tool such as a screwdriver, thereby completing the insertion of the intervertebral fusion cage <NUM>.

Similarly, when the intervertebral fusion cage <NUM> is incorrectly inserted or removed for a reoperation, the locking bolt <NUM> is reversely rotated with a tool such as a screwdriver, and the locking plate <NUM> is separated from the proximal movable block <NUM>. Then, the bone screws <NUM>, <NUM>, <NUM>, or <NUM> are rotated with a tool such as a screwdriver to separate the bone screws <NUM>, <NUM>, <NUM>, or <NUM> from the intervertebral fusion cage <NUM>. In this case, the bone screws <NUM>, <NUM>, or <NUM> having anchor portions may be separated from the intervertebral fusion cage <NUM> by unfastening the threaded portions of the bone screws <NUM>, <NUM>, or <NUM> and then pulling the bone screws <NUM>, <NUM>, or <NUM> with a tool such as an awl.

Thereafter, in a state in which the intervertebral fusion cage <NUM> is held using a cage holder (not shown), the proximal movable block <NUM> and the distal movable block <NUM> are moved away from each other by inserting a tool such as a screwdriver into the adjustment member <NUM> and reversely rotating the tool. Then, the first end plate <NUM> and the first plate body <NUM> are moved close to each other, and thus the height of the intervertebral fusion cage <NUM> is reduced. Thereafter, the intervertebral fusion cage <NUM> is removed from the vertebral bodies.

While preferred embodiments of the present disclosure have been described, as described above, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the scope of the present disclosure as defined by the following claims.

According to the present disclosure, only one cage may be used for a given height range, thereby reducing inventory and production, and repetitive tasks and burdens on surgeons during surgery. In addition, the operation time and the amount of bleeding may be reduced, and thus the recovery time of patients may be greatly reduced. Therefore, the present disclosure may be widely used in related fields.

Claim 1:
An intervertebral fusion cage comprising:
a first end plate (<NUM>) and a second end plate (<NUM>), which are configured to be in contact with adjacent vertebral bodies;
a distal movable block (<NUM>) fixed in a state in which the distal movable block is movable relative to a plate slope portion formed on an end of the first end plate and a plate slope portion formed on an end of the second end plate;
a proximal movable block (<NUM>) fixed in a state in which the proximal movable block is movable relative to a plate slope portion formed on another end of the first end plate and a plate slope portion formed on another end of the second end plate;
an adjustment member (<NUM>) rotatably fixed to the proximal movable block and screwed to the distal movable block to adjust a distance between the distal movable block and the proximal movable block;
a first guide portion formed on the first end plate toward the second end plate;
a second guide portion formed on the second end plate toward the first end plate to limit, by sliding between the first guide portion and the second guide portion, a movement direction in which the first end plate and the second end plate are moved close to or away from each other;
a bone screw (<NUM>) configured to be inserted into bone screw holes (<NUM>) formed in the first end plate and the second end plate; and
a locking member (<NUM>,<NUM>) configured to be fastened to the proximal movable block to prevent separation of the bone screw,
wherein the first guide portion and the second guide portion support a load in a length or width direction of the first end plate and the second end plate.