Height-adjustable spinal fusion cage

Abstract

To provide a spinal fusion cage which is inserted between vertebral bodies at the minimum height, can adjust the height in the inserted state, can stably support the movement of a pair of end plates, and can particularly simplify an instrument for adjusting the height.SOLUTION: With respect to a spinal fusion cage, a single cage can replace a cage having a height within a certain range. Therefore, the number of product groups to be produced by the manufacturer is reduced, and the inventory can be reduced. In addition, unlike a cage having a predetermined height at a predetermined interval in the prior art, the height of the cage is linearly adjusted according to the interval between the vertebral bodies of the patient, and thus surgery may be performed at an optimal height according to the state of the patient.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a height-adjustable spinal fusion cage, and more particularly, to a spinal fusion cage that can be inserted between vertebral bodies at a minimum height and has its height adjusted while inserted, and in particular, that can simplify the tools for adjusting the height. [Background technology]

[0002] The vertebral body is made up of 32 to 35 vertebrae that make up the torso and the intervertebral disks between the vertebrae, and is the central part of the human body that connects the skull at the top and the pelvis at the bottom.

[0003] The spine consists of seven cervical vertebrae, 12 thoracic vertebrae, five lumbar vertebrae, five sacrum vertebrae, and three to five coccyx vertebrae. In adults, five sacral vertebrae are fused to form one sacrum, and three to five coccyx vertebrae are fused to form one coccyx.

[0004] Spinal fusion has long been one of the treatment methods for serious spinal diseases. Spinal fusion is a surgical procedure that removes the intervertebral disc and inserts a cage to fuse the adjacent vertebrae together.

[0005] When spinal fusion is performed on the lumbar spine, it can be classified into posterior lumbar interbody fusion (PLIF), transformational lumbar interbody fusion (TLIF), lateral lateral lumbar interbody fusion (LLIF), oblique lumbar interbody fusion (OLIF), anterior lumbar interbody fusion (ALIF), etc., depending on the direction of cage insertion.

[0006] Posterior interbody fusion (PLIF) involves making an incision along the centerline of the spine, opening it to expose the entire vertebral body, removing part of the posterior side of the vertebra, removing the disc, and inserting a PLIF cage.

[0007] Posterior interbody fusion (PLIF) is the oldest spinal fusion procedure and is a necessary method when fusing two or three joints. However, it has the disadvantages of a high possibility of adhesions occurring to nerves, ligaments, and muscles during the surgery, a long healing time due to the large incision area, and serious aftereffects in some people.

[0008] The PLIF cage consists of a pair of small cages placed on either side of the bone and is the smallest of all cages used in spinal fusion surgery.

[0009] Transverse foraminal lumbar fusion (TLIF) is a surgical method in which small incisions are made along both sides of the spinal muscles to expose the vertebral body to a minimum extent, and then the spinal joint area is removed in the direction of the neural foramen and a TLIF cage is inserted. This surgical technique has the advantages of less bleeding and shorter surgery time, so it is suitable for surgery on one joint, but if surgery is required on multiple areas, a PLIF operation must be performed. Most TLIF cages are arc-shaped, so they are inserted into the vertebral body and rotated so that the bulging part of the TLIF cage faces the ventral side. The TLIF cage is larger than the PLIF cage, but its support area is smaller than the LLIF cage or ALIF cage, which will be explained later.

[0010] Anterior lumbar interbody fusion (ALIF) has many advantages, such as quick recovery and no worries about adhesions, but it has the disadvantage of requiring highly skilled techniques to perform the procedure by making an incision on the front (ventral side) and approaching the spine while turning over the internal organs. The ALIF cage has the advantage of having the largest support area of ​​all spinal fusion cages.

[0011] Among such ALIF cages, an integrated cage has been disclosed that has holes through which screws can be inserted and fixed into the vertebral body to prevent the cage from becoming detached after surgery (Patent Document 3: US2014-0277487A).

[0012] Patent Document 1: US9585762 and Patent Document 2: US2019-0133782A disclose a free-standing ALIF cage with adjustable height. However, Patent Document 1: US9585762 adjusts the height using a vertical ratchet 302, and is characterized by essentially adjusting the angle rather than the height. Patent Document 2: US2019-0133782A adjusts the height, but has a problem of being difficult to manufacture due to its very complicated structure.

[0013] In the cervical spine, cage insertion is only possible in Anterior Lumbar Interbody Fusion (ACIF). The ACIF cage is very low in height, making it difficult to adjust the height compared to ALIF, and US Patent No. 4: US10034767 has been published, which can also be used as an ACIF cage. However, US Patent No. 4: US10034767 is closed off by walls around it, which is disadvantageous in terms of the supply of osteogenic materials.

[0014] In addition, in the case of the height-adjustable cage, the adjacent vertebrae are forcibly expanded while the cage is in place, so if excessive force is applied, the vertebrae may be damaged. To solve this problem, a torque limit handle is connected to the driver used to expand the vertebrae, so that the driver can be used only within a certain torque range. However, the torque limit handle has a disadvantage of being heavy and complicated in structure.

[0015] If surgical instruments are complicated, cleaning and sterilization may be incomplete if they are reused after cleaning and sterilization. Also, if the instruments are heavy, it may be inconvenient for doctors to hold and use them, and the weight of the containers in which the instruments are stored may increase, which may be a burden when transporting them. [Prior art documents] [Patent documents]

[0016] [Patent Document 1] US9585762 [Patent Document 2] US2019-0133782A [Patent Document 3] US2014-0277487A [Patent Document 4] US10034767 Summary of the Invention [Problem to be solved by the invention]

[0017] The present invention has been devised to solve the above problems, and aims to provide a spinal fusion cage that can be inserted between vertebral bodies at a minimum height, can adjust its height while inserted, can stably support the movement of a pair of end plates, and can simplify the tool for adjusting the height. [Means for solving the problem]

[0018] In order to achieve the above-mentioned object, the present invention provides a vertebral column that includes a first end plate and a second end plate that contact adjacent vertebral bodies; a distal moving block that is fixed to be relatively movable to a plate inclined portion formed at one end of the first end plate and the second end plate; a proximal moving block that is fixed to be relatively movable to a plate inclined portion formed at the other end of the first end plate and the second end plate; an adjustment member that is rotatably fixed to the proximal moving block and is screw-coupled to the distal moving block to adjust the distance between the distal moving block and the proximal moving block; and a second guide portion formed on the second endplate toward the first endplate and restricting the direction of movement of the first endplate and the second endplate toward or away from each other by a sliding motion with the first guide portion, the first guide portion and the second guide portion being formed to support loads in the length direction or width direction of the first endplate and the second endplate, and the separable portion is disposed at a proximal end of the adjustment member and connected by a connecting portion that breaks when a predetermined torque is applied.

[0019] The implant may further include bone screws inserted through bone screw holes formed in the first end plate and the second end plate.

[0020] The distal moving block and the proximal moving block may be provided with block sliders, and the plate inclined portion may be provided with a plate slider that slides relative to the block slider.

[0021] The adjustment member may have a threaded portion at one end that is threadably coupled to the distal moving block, and an adjustment member support surface at the other end that is rotatable in place relative to the proximal moving block.

[0022] The proximal movement block may also have an inner fastening portion spaced apart from the outer surface of the adjustment member in a proximal direction from the adjustment member support surface.

[0023] The proximal moving block may have an outer fastening portion formed on an outer surface thereof.

[0024] The proximal moving block may have an inner fastening portion spaced apart from the outer surface of the adjustment member in a proximal direction from the adjustment member support surface, and an outer fastening portion may be formed on the outer surface of the proximal moving block.

[0025] The separable portion is further characterized in that a first instrument fastening portion for fastening to an instrument is formed on an outer surface of the separable portion.

[0026] In addition, the adjustment member head formed on one side of the proximal direction of the adjustment member has a second instrument fastening portion formed on an outer surface thereof so as to be fastened to an instrument.

[0027] The first instrument fastening portion and the second instrument fastening portion are also characterized in that their cross-sectional shapes are identical.

[0028] The separable portion is also characterized in that the inside thereof is perforated.

[0029] The connecting portion may be disposed along a proximal edge of the adjustment member head, and may include at least two connecting units.

[0030] The connecting unit may have a notch formed on an inner or outer circumferential side of the adjustment member head.

[0031] The first guide portion may include a pillar protruding toward the second end plate, and the second guide portion may include an extension wall protruding toward the first end plate to enable sliding motion relative to the pillar.

[0032] In addition, a receiving portion capable of receiving the extension wall when the first end plate and the second end plate approach each other is formed around the pillar.

[0033] The extension wall may be formed with a guide groove for guiding the insertion of the pillar.

[0034] The bone screw is also characterized in that it has an anchor portion at its distal end that does not have a thread.

[0035] The anchor portion has an anchor groove formed in the longitudinal direction of the bone screw. Effect of the Invention

[0036] Through the present invention, one cage can replace cages having a certain range of heights. Therefore, manufacturers can reduce the number of products they need to produce and reduce inventory. Also, unlike conventional cages with preset heights at certain intervals, the height is adjusted linearly according to the intervals between the vertebrae of the patient, making it possible to perform surgery at an optimal height according to the patient's condition.

[0037] In addition, because the cage is inserted at the minimum height, it reduces the burden of having to separately produce test inserts to match the existing appropriate vertebral spacing, and it also saves doctors the trouble of having to insert multiple test inserts in sequence to secure insertion space.

[0038] In addition, the tool for adjusting the height can be simplified through the adjustment member that breaks when a predetermined torque is applied. [Brief description of the drawings]

[0039] [Figure 1] FIG. 2 is a top front perspective view of an embodiment of a spinal fusion cage in accordance with the present invention in a minimum height position. [Diagram 2] FIG. 2 is a perspective view of the spinal fusion cage of FIG. 1 from above and behind in a minimum height state. [Diagram 3] FIG. 2 is a front, top-view perspective view of the spinal fusion cage of FIG. 1 in a maximum height position. [Figure 4] FIG. 2 is a perspective view of the spinal fusion cage of FIG. 1 from above and behind in a maximum height position. [Diagram 5] 2 is a cross-sectional perspective view of the spinal fusion cage of FIG. 1 cut vertically along the anterior-posterior direction and viewed from above the front. FIG. [Figure 6] 2 is a cross-sectional perspective view of the spinal fusion cage of FIG. 1 cut vertically along the anterior-posterior direction and viewed from above the posterior surface. FIG. [Figure 7] FIG. 2 is an exploded front perspective view of the spinal fusion cage of FIG. 1. [Figure 8] FIG. 2 is an exploded perspective posterior view of the spinal fusion cage of FIG. 1. [Figure 9] FIG. 2 is a perspective view from below of the front side of a first endplate of the spinal fusion cage of FIG. 1. [Figure 10] FIG. 2 is a top-down perspective view of the rear surface of the first endplate of the spinal fusion cage of FIG. 1. [Figure 11] FIG. 2 is a top perspective view of the front of a second endplate of the spinal fusion cage of FIG. 1. [Figure 12] FIG. 2 is a perspective view from below of the rear surface of the second endplate of the spinal fusion cage of FIG. 1. [Figure 13] FIG. 2 is a top perspective view of the front of the proximal movement block of the spinal fusion cage of FIG. 1. [Figure 14] FIG. 2 is a top perspective view of the rear surface of the proximal movement block of the spinal fusion cage of FIG. 1. [Figure 15] FIG. 2 is a top perspective view of the front of a distal movement block of the spinal fusion cage of FIG. 1. [Figure 16] FIG. 2 is a top-down perspective view of the rear face of the distal movement block of the spinal fusion cage of FIG. 1. [Figure 17] 2 is a top perspective view of the front of an adjustment member of the spinal fusion cage of FIG. 1. FIG. [Figure 18] FIG. 2 is a top perspective view of the rear of the adjustment member of the spinal fusion cage of FIG. 1. [Figure 19] FIG. 2 is a bone screw used in the spinal fusion cage of FIG. 1. [Figure 20] 2 is a first variation of an adjustment member for use in the spinal fusion cage of FIG. 1. [Figure 21] 2 is a second variation of an adjustment member for use in the spinal fusion cage of FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] Hereinafter, the present invention will be described with reference to the drawings in which preferred embodiments are attached. In the following drawings, when reference numerals are used to denote components, the same reference numerals are used as much as possible even if the same components are shown in different drawings, and detailed description of known functions and configurations that may unnecessarily obscure the gist of the present invention will be omitted.

[0041] In the following, distal direction means the direction in which the cage is inserted and proximal direction means the direction opposite to distal direction.

[0042] 1 to 8 show an entire spinal fusion cage 100 according to an embodiment, and FIGS. 9 to 21 show each element of the spinal fusion cage 100. As shown in FIG.

[0043] The spinal fusion cage 100 is large and comprises a first end plate 102 and a second end plate 104 arranged facing each other vertically, a distal moving block 108 and a proximal moving block 106 arranged between the first end plate 102 and the second end plate 104 and moving depending on the distance between the first end plate 102 and the second end plate 104, and an adjustment member 110 that passes through the proximal moving block 106 and connects to the distal moving block 108.

[0044] The first end plate 102 and the second end plate 104 have a first plate body 104 and a second plate body 146 having teeth on the surface that contacts the vertebral body. The teeth are formed to prevent the vertebral body from coming off, and can be deformed in various ways. In addition, a first window 144 and a second window 172 for inserting a bone graft are formed in the center of the first plate body 104 and the second plate body 146, respectively.

[0045] 9 and 10, the first plate body 122 is formed with a proximal moving block seat 130 in the proximal direction along the length direction, and a distal moving block seat 138 in the distal direction. A plate inclined portion 128 is formed extending from the proximal moving block seat 130, and a pair of plate sliders 132 are formed facing each other on both sides of the plate inclined portion 128. A bone screw hole 134 is formed on the outside of the plate slider 132. The bone screw hole 134 is penetrated so that a bone screw 120 can be inserted, and a guide surface 136 for guiding the bone screw 120 may be formed on the inlet side of the bone screw hole 134. A plate inclined portion 140 is formed around the distal moving block seat 138. The plate inclined portion 140 is formed on both ends of the distal moving block seat 138, and plate sliders 142 are formed on the outside of the plate inclined portion 140. The plate slider 132 formed at the proximal portion and the plate slider 142 formed at the distal portion are formed to be inclined in a direction approaching the center of the first plate body 122 as they go from the surface of the first plate body 122 in the thickness direction.

[0046] Similarly, as shown in Figs. 11 and 12, the second plate body 146 is formed with a proximal moving block seat 156 in the proximal direction along the length direction, and a distal moving block seat 164 in the distal direction. A plate inclined portion 154 is formed extending from the proximal moving block seat 156, and a pair of plate sliders 158 are formed facing each other on both sides of the plate inclined portion 154. A bone screw hole 160 is formed on the outer side of the plate slider 158. The bone screw hole 160 is penetrated so that a bone screw 120 can be inserted, and a guide surface 162 for guiding the bone screw 120 may be formed on the inlet side of the bone screw hole 160. A plate inclined portion 166 is formed around the distal moving block seat 164. The plate inclined portion 166 is formed on both ends of the distal moving block seat 164, and plate sliders 168 are formed on the outer sides of the plate inclined portion 166. The plate slider 158 formed at the proximal portion and the plate slider 168 formed at the distal portion are formed to be inclined in a direction approaching the center of the second plate body 146 as they go in the thickness direction from the surface of the second plate body 146.

[0047] As shown in Figs. 13 and 14, the proximal moving block 106 has a block inclined portion 190 formed on the proximal side centered on a proximal connecting tube 190 having an adjusting member hole 188 into which the adjusting member 110 is inserted and supported. Block sliders 180 are disposed on both sides of the block inclined portion 190, which are slidably coupled to plate sliders 132 and 158 formed on the first and second end plates 102 and 104. The adjusting member hole 184 has a support portion 184 that contacts and supports the adjusting member 110, and a support step 186 is formed around the support portion 184 to prevent the adjusting member 110 from coming off. In addition, a pin hole 178 in which a pin member 118 can be installed is formed on the side of the proximal moving block 106 to prevent the adjusting member 110 located at the support portion 184 from coming off proximally. An outer fastening portion 176 is formed on a side of the proximal movement block 106 so that an instrument can fix the spinal fusion cage 100. The outer fastening portion 176 may be formed with a protrusion or a screw thread, etc., and may be used to connect with an instrument or to connect with another implant such as a plate. An inner fastening portion 182 may be formed on the inner side of the outer fastening portion 176 around the periphery of the adjustment member 110. The inner fastening portion 182 may be formed with a screw thread, and may be used to connect with an instrument or to connect with another implant such as a plate.

[0048] 15 and 16, the terminal moving block 108 is formed with a terminal connection tube 198 having a moving block threaded portion 202 at its center, which is threadably coupled with the adjustment member 110, and has wings 196 on both sides of the terminal connection tube 198. The wings 196 are formed with block inclined portions 194, and block sliders 204 are disposed on both sides of the wings 196. The block sliders 204 are slidably coupled with the plate sliders 142, 168 of the first and second end plates 102, 104, respectively.

[0049] The distal moving block 108 has a distal wall 192 for easy insertion between vertebral bodies in the distal direction, and the distal wall 192 is integral with the block inclined portion 194. In addition, when the height is at its lowest, the distal wall 192 contacts the end of the first end plate 102 and the end of the second end plate 104 to form a single insertion portion as a whole. In particular, distal folding surfaces 208 are formed on both sides of the distal wall 192 to further facilitate insertion.

[0050] The distal moving block 108 and the proximal moving block 106 have a generally wedge-shaped structure and apply a force to the first end plate 102 and the second end plate 104 to raise and lower them.

[0051] The adjustment member 110 may have a substantially bolt-like shape as shown in Figures 17 and 18. Modified adjustment members 310 and 410 are also shown in Figures 20 and 21. The three adjustment members 110, 310 and 410 will be described below at one time, and only the features of each will be described. The adjustment members 110, 310 and 410 each have an adjustment member head 220, 320 and 420, an adjustment screw portion 214, 314 and 414 that is integrally connected to the adjustment member head 220, 320 and 420 at the distal end and is screwed to the moving block screw portion 202 of the distal moving block 108, and a separable portion 218, 318 and 418 that is connected to the adjustment member head 220, 320 and 420 in the proximal direction through a connecting portion 222, 322 and 422.

[0052] An adjustment member support surface 212 may be formed between the adjustment member head 220, 320, 420 and the adjustment screw portion 214, 314, 414. A pin support portion 228, 328, 428 is formed on the proximal side of the adjustment member support surface 212, 312, 412, and a pin seat 216, 316, 416 where an end of the pin member 118 is located is formed on the proximal side of the pin support portion 228, 328, 428. Therefore, the adjustment member 110, 310, 410 rotates with the adjustment member support surface 212, 312, 412 contacting the support portion 188 while the pin support portion 228, 328, 428 is supported by the support step 186 of the proximal moving block 106. As a result, the adjustment member 120 can rotate in place inside the adjustment member 110.

[0053] An adjustment member head 220, 320, 420 is formed on the proximal side of the adjustment member 110, 310, 410, and the detachable portion 218, 318, 418 is connected to the proximal side of the adjustment member head 220, 320, 420 by the connecting portion 222, 322, 422.

[0054] A first instrument fastening portion for fastening to an instrument may be formed on an outer surface of the separable portion 218, 318, 418. The first instrument fastening portion may be formed in a hexagonal shape as shown in Figures 17 and 18, or in a star or square shape as shown in Figures 20 and 21. However, the shape is not limited thereto and various modifications are possible.

[0055] Similarly, the adjustment member head 220, 320, 420 may have a second instrument fastening portion formed on its outer surface so as to be connected to an instrument. The second instrument fastening portion may be formed in a hexagonal shape as shown in Figures 17 and 18, or in a star or square shape as shown in Figures 20 and 21. However, the present invention is not limited thereto and various modifications are possible.

[0056] In particular, the cross-sectional shapes of the first and second instrument fastening parts may be formed to be the same. In this case, there are various advantages. First, if a driver (not shown) is formed with long grooves corresponding to the first and second instrument fastening parts, the driver can be pushed all the way in to simultaneously contact the separable parts 218, 318, 418 and the adjustment member heads 220, 320, 420. In this case, the separable parts 218, 318, 418 can transmit torque without being cut off, so that it can be used when necessary under the judgment of a doctor. In addition, if a driver is selectively rotated with only the separable parts 218, 318, 418 inserted, the separable parts 218, 318, 418 can be separated from the adjustment member heads 220, 320, 420. In addition, after the spinal fusion cage 100 is attached to the patient's body with a screwdriver, if the cage is later replaced with another product, the adjustment member heads 220, 320, 420 can be rotated with the same screwdriver, which is cost-effective in preparing the instrument.

[0057] In order to enhance the role of the driver, a groove such as a "1"-shaped groove or a "C"-shaped groove can be machined on the proximal end side of the detachable portion 218, 318, 418 to replace or assist the first instrument fastening portion.

[0058] In addition, the interior of the separable portion 218, 318, 418 may be penetrated and communicate with the opening groove 226, 326, 426 formed in the adjustment member head 220, 320, 420. The opening groove 226, 326, 426 may have a driver tip shape, in which case the through hole 224, 324, 424 may use the opening groove 226, 326, 426 to adjust the position of the adjustment member 110, 310, 410 when the separable portion 218, 318, 418 is still integral.

[0059] The connecting portion 222, 322, 422 is disposed along the proximal edge of the adjustment member head 220, 320, 420, and the connecting portion 222, 322, 422 may be composed of at least two connecting units. The connecting units may separate the adjustment member head 220, 320, 420 and the separable portion 218, 318, 418 with a gap. The connecting units may have a notch formed on the inner or outer circumferential side of the adjustment member head 220, 320, 420. Thus, a designer can set a required limit torque value by the number of the connecting units, the circumferential length and radial thickness of the connecting units, and the size of the notch. Thus, since the limit torque value of the connecting portions 222, 322, 422 can perform the function of the torque limit handle used in the prior art, a torque limit handle can be omitted from the screwdriver required to rotate the adjustment member 110, 310, 410. Thus, the tool can be simple and light. In particular, in the case of torque limit handles, the set value changes with prolonged use, and periodic adjustment or replacement is required. However, in the spinal fusion cage 100 according to the present invention, when a product is manufactured according to a quality procedure through a certain process in a factory, the limit torque value of the connecting parts 222, 322, 422 becomes constant within an allowable error range, so that the limit torque value can be kept constant even over time.

[0060] In Figures 17 and 18, separable portion 218 is hexagonal in shape so that a driver similar to a hexagonal wrench can be used, and in Figure 20, separable portion 318 is star-shaped so that a star-shaped driver can be used. It is believed that further variations are possible, such as separable portion 418 in Figure 21, which has a square cross section.

[0061] A pair of pillars 124 are formed on both sides of the first plate body 122 in a thickness direction, i.e., toward the second end plate 104. A receiving portion 126 is formed around the pillars 124 in which an extension wall 148, which will be described below, can be received. An extension wall 148 is formed on both sides of the second plate body 146 in a thickness direction, i.e., toward the first end plate 102, and a groove 150 is formed inside the extension wall 148 in which the pillars 124 can be guided while being received. As a result, the pillars 124 are received inside the groove 150 and move up and down, so that the first end plate 102 and the second end plate 104 are restricted from moving toward or away from each other. Here, the pillars 124 and the extension wall 148 correspond to a first guide portion and a second guide portion. The first guide portion and the second guide portion function to support the first end plate 102 and the second end plate 104 against a load or torsion in the length direction or width direction.

[0062] Also, the extension wall 148 has a substantially U-shape when viewed from above, and is formed to surround the pillar 124. More specifically, the extension wall 148 includes a first wall 1481 located in a proximal direction, a second wall 1482 located in a distal direction, and a third wall 1483 connecting the first wall 1481 and the second wall 1482. When viewed from the center of the groove 150, the first wall 1481 and the second wall 1482 are located on the bottom surface (opposite surface facing the vertebral body) side of the first and second end plates 102 and 104 so as to maintain the width of the groove 150 as it is. And, the third wall 1483 is formed so as to maintain the depth of the groove 150 in the direction opposite to the direction in which the groove 150 is opened. Therefore, the thickness of the pillar 124 can be increased not only in the length direction but also in the width direction. As a result, the shear force in the length direction can be supported by the first wall 1481 and the second wall 1482, and the shear force in the width direction can be supported by the third wall 1483. Therefore, the strength against the shear force in the length direction and the width direction can be dramatically increased.

[0063] Next, the bone screw 120 used in the embodiment will be described with reference to FIG.

[0064] 20 includes a screw head 236 that limits the amount of insertion of the bone screw 120 when inserted into the bone screw holes 134 and 160, an instrument seat 238 formed in the screw head 236 to be fastened to a tool, and a threaded portion 240 that is a region that is inserted into the vertebral body together with the screw head 236. The threaded portion 240 can selectively use a double thread or a single thread to fit cancellous bone and cortical bone.

[0065] In particular, an anchor portion 242 is formed at the end of the threaded portion 240 that is inserted into the vertebral body. According to the prior art, a separate tool such as an awl is required to set the initial direction when inserting a bone screw into a bone. In particular, in cancellous bone, the fixing strength of the screw is not large, so the thread in this area is often not very meaningful. Therefore, the bone screw 242 has a certain area formed as an anchor portion 242 at the end of the threaded portion 248, so that a separate tool is not required to set the initial direction, and the bone screw 242 is inserted by striking the certain area, which reduces the inconvenience of rotating the screw.

[0066] The anchor portion 242 is shaped like a nail, and only the end of the shank is conical to facilitate insertion of the tip. Also, the anchor portion 242 may have an anchor groove formed in the length direction of the bone screw 252, and in this case, the contact area with the bone is increased to increase the fixing force.

[0067] The spinal fusion cage 100 is constructed as described above, and the method of operating the spinal fusion cage 100 will be described below.

[0068] First, a surgical path to the vertebrae is secured using surgical tools, and the target disk is removed. Then, the spinal fusion cage 100 is inserted between the vertebrae from which the disk has been removed while being held by a cage holder (not shown).

[0069] Thereafter, a tool such as a screwdriver is fastened to the separable portion 218, 318, 418 of the adjustment member 110, and the proximal moving block 106 and the distal moving block 108 are brought closer to each other by rotating the screwdriver in one direction, and as a result, the first end plate 102 and the second end plate 104 are separated from each other. At this time, when the torque of the screwdriver becomes greater than a predetermined torque determined by the connecting portions 222, 322, 422, the connecting portions 222, 322, 422 are broken, and the separable portions 218, 318, 418 are separated from the adjustment member heads 220, 320, 420. Therefore, it is possible to prevent the spinal fusion cage 100 from transmitting an excessive load to the vertebral body.

[0070] Then, the bone screw 120 is inserted and fixed into the bone screw holes 134, 160 of the first end plate 102 and the second end plate 104. At this time, a hole is first formed by an awl tool to insert the bone screw 120, and a drill is used to deepen the hole through the previously formed hole. Then, a tapper tool is used to make the thread slightly smaller than the bone screw 120 to create a path for the thread, and the bone screw 120 is rotated and inserted by a tool such as a screwdriver. The formation of the thread by the tapper may be omitted. However, since the bone screw 120 has an anchor portion 242 formed at its end, when inserting the bone screw 120, such tools as an awl, drill, tapper, etc. are omitted, and the bone screw 120 is immediately struck by a mallet tool, etc., to set the direction and initially insert the bone screw 120, and then rotated by a screwdriver tool, etc. to insert the remaining threaded portion. This completes the insertion process of the spinal fusion cage 100.

[0071] Similarly, if the spinal fusion cage 100 is to be removed due to erroneous insertion or reoperation, the bone screw 120 is rotated with a tool such as a screwdriver to separate it from the spinal fusion cage 100. In the case of the bone screw 120 having an anchor portion, after the threaded region is separated, it is grasped with tweezers or the like and pulled out to separate it.

[0072] Then, while holding the spinal fusion cage 100 with a cage holder (not shown), an instrument such as a screwdriver is inserted into the adjustment member 110 and rotated in the other direction to increase the distance between the proximal moving block 106 and the distal moving block 108, thereby decreasing the distance between the first end plate 102 and the second end plate 104 and reducing the overall height, thereby allowing the cage to be removed from the vertebral body.

[0073] As described above, the present invention has been described with reference to a preferred embodiment. However, it will be understood by those skilled in the art that various modifications and variations of the present invention can be made without departing from the spirit and scope of the present invention as set forth in the claims below. [Industrial Applicability]

[0074] The present invention has the advantages of being able to accommodate a certain range of heights with one cage, thereby reducing inventory and production burdens, reducing repetitive tasks during surgery, and reducing the burden on doctors. It also has the advantages of reducing surgery time, reducing bleeding, and significantly shortening patient recovery time, and is therefore expected to be widely used in the relevant fields. [Explanation of symbols]

[0075] 100: Spinal fusion cage 102: First end plate 104: 2nd end plate 106: Proximal mobile block 108: Terminal moving block 110, 310, 410: Adjustment member 118: Pin component 120: Bone screw 122: First plate body 124: Pillar 126: Storage groove 128, 140, 154, 166: Plate inclination 130, 156: Seat of proximal mobile block 132, 142, 158, 168: Plate slider 134, 160: Bone screw holes 136, 162: Guide surface 138, 164: Seats in the terminal block 144: First window 146: 2nd plate body 148: Extension wall 150: Groove 152: Information department 172: Second window 174, 192: Block body 176:Outer fastening part 178: Pinhole 180, 204: Block slider 182:Inner fastening part 184: Adjustment component hole 186: Support stage 188: Support part 190, 194: Block inclination section 192: End wall 196: Wings 198: Terminal connection tube 202: Moving block screw part 208: Terminal bend surface 212, 312, 412: Adjustment member support surface 214, 314, 414: Adjustment screw part 216, 316, 416: Pin seats 218, 318, 418: Separable part 220, 320, 420: Adjustment member head 222, 322, 422: Connection part 224, 324, 424: Through holes 226, 326, 426: Open groove 228, 328, 428: Pin support 236: Screw head 238: Instrument seat 240: Threaded part 242: Anchor section 1481: 1st wall 1482:Second wall 1483: Third wall

Claims

1. a first endplate and a second endplate contacting adjacent vertebral bodies; a terminal moving block fixed to be movable relative to a plate inclined portion formed at one end of the first end plate and the second end plate; a proximal moving block fixed to be relatively movable on a plate inclination portion formed on the other end of the first end plate and the second end plate; an adjustment member rotatably secured to the proximal moving block and threadably coupled to the distal moving block to adjust the distance between the distal moving block and the proximal moving block; a first guide portion formed on the first end plate toward the second end plate; and a second guide portion formed on the second end plate toward the first end plate and configured to restrict a direction in which the first end plate and the second end plate move toward or away from each other by a sliding motion with the first guide portion; the first guide portion and the second guide portion are formed to support a load in a length direction or a width direction of the first end plate and the second end plate, An adjustment member head is formed on one side of the proximal direction of the adjustment member, and a separable portion is disposed on the proximal end of the adjustment member and connected to the adjustment member head by a connection portion that breaks when a predetermined torque is applied to the proximal end of the adjustment member.

1. A spinal fusion cage comprising:

2. The bone screw may further include a bone screw inserted through a bone screw hole formed in the first end plate and the second end plate.

10. The spinal fusion cage of claim 1.

3. The distal moving block and the proximal moving block are provided with block sliders, and the plate inclination portion is provided with a plate slider that slides relative to the block slider.

10. The spinal fusion cage of claim 1.

4. The adjustment member has a threaded portion at one end that threadably engages with the distal translation block and an adjustment member support surface at the other end that is rotatable in place relative to the proximal translation block.

10. The spinal fusion cage of claim 1.

5. The proximal travel block has an inner fastening portion spaced proximally from the adjustment member support surface relative to an outer surface of the adjustment member.

5. The spinal fusion cage of claim 4.

6. The outer surface of the proximal moving block is formed with an outer fastening portion.

5. The spinal fusion cage of claim 4.

7. The proximal movement block has an inner fastening portion spaced from the adjustment member support surface in a proximal direction on an outer surface of the adjustment member, and an outer fastening portion is formed on the outer surface of the proximal movement block.

5. The spinal fusion cage of claim 4.

8. The separable portion has an outer surface formed with a first instrument fastening portion for fastening to an instrument.

10. The spinal fusion cage of claim 1.

9. The adjustment member head formed on one side of the proximal direction of the adjustment member has a second instrument fastening portion formed on its outer surface so as to be fastened to an instrument.

9. The spinal fusion cage of claim 8.

10. The first and second instrument fastening portions have the same cross-sectional shape.

10. The spinal fusion cage of claim 9.

11. The interior of the separable portion is perforated.

9. The spinal fusion cage of claim 8.

12. The linkage is disposed along a proximal edge of the adjustment member head, the linkage comprising at least two linkage units.

10. The spinal fusion cage of claim 9.

13. The connecting unit has a notch formed on the inner or outer circumferential side of the adjustment member head.

13. The spinal fusion cage of claim 12.

14. 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 to allow sliding movement relative to the pillar.

10. The spinal fusion cage of claim 1.

15. When the first end plate and the second end plate approach each other, a receiving portion capable of receiving the extension wall is formed around the pillar.

15. The spinal fusion cage of claim 14.

16. The extension wall is formed with a guide groove for guiding the insertion of the pillar.

15. The spinal fusion cage of claim 14.

17. The bone screw has an unthreaded anchor portion at its distal end.

3. The spinal fusion cage of claim 2.

18. The anchor portion has an anchor groove formed in the longitudinal direction of the bone screw.

20. The spinal fusion cage of claim 17.

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