111. The catching portion 132 may, while inserted into the first grooves 111a, limit the rotation of the screw head 111 before the torque greater than or equal to the threshold torque acts on the screw 110, and may be pressed by the first protruding portion 111b adjacent thereto and separated from the first grooves 111a in a case where the torque greater than or equal to the threshold torque acts on the screw 110. In relation to this, in the case where the torque greater than or equal to the threshold torque is applied to the screw 110, the member body 131 may be elastically deformed.

The separation preventing member 140 is disposed to be fixed to the housing 120 while inserted into one portion of the second groove 111c and prevents the screw 110 from being separated from the housing 120. In one embodiment of the present invention, the separation preventing member 140 may be formed in the shape of a pin. More specifically, in a state in which the separation preventing member 140 is inserted into the separation preventing member arrangement portion 124 formed as the through-hole passing through both sides of the housing body 121, at least a portion of the separation preventing member 140 may be inserted into the second groove 111c of the screw head 111. Also, the separation preventing member 140 may be disposed perpendicular to the screw 110.

FIG. 5 is a perspective view of an intervertebral fusion cage according to one embodiment of the present invention, and FIG. 6 is a perspective view illustrating the intervertebral fusion cage according to one embodiment of the present invention in another direction. Also, FIG. 7 is an exploded perspective view of the intervertebral fusion cage according to one embodiment of the present invention.

An intervertebral fusion cage 1000 according to one embodiment of the present invention is a device used in fusion which is a surgical method for treating spinal diseases. The intervertebral fusion cage 1000 according to one embodiment of the present invention includes a screw driving module 1100 as a driving system. Also, the intervertebral fusion cage 1000 according to one embodiment of the present invention is inserted into a portion between vertebrae, from which a degenerative disc has been removed, and serves to support the portion between the vertebrae until spinal fusion is performed. The intervertebral fusion cage 1000 according to one embodiment of the present invention allows both lordosis and height of the spine to be secured.

Referring to FIGS. 5 to 7, the intervertebral fusion cage 1000 according to one embodiment of the present invention may include the screw driving module 1100, a guide member 1200, and a plate 1300.

The screw driving module 1100 moves relative to the guide member 1200 according to rotation of a screw 1110 and causes displacement of the plate 1300. The screw driving module 1100 may include the screw 1110, a housing 1120, a threshold torque setting member 1130, and a separation preventing member 1140.

The screw 1110 includes a screw head 1111 and a screw body 1112 extending from the screw head 1111 and having screw threads 1112a on an outer circumferential surface thereof.

The screw head 1111 has one or more first grooves 1111a on an outer circumferential surface thereof. The first grooves 1111a may be formed in the longitudinal direction of the screw 1110. Also, a plurality of the first grooves 1111a may be disposed at predetermined intervals in a circumferential direction of the screw head 1111. Meanwhile, a first protruding portion 1111b protruding radially outward relative to the first grooves 1111a is formed between adjacent first grooves 1111a.

Also, the screw head 1111 may further include a second groove 1111c continuously recessed in the circumferential direction. The second groove 1111c is formed for the separation preventing member 1140 to be inserted thereinto.

The screw body 1112 is connected to the screw head 1111 and has the screw threads 1112a on the outer circumferential surface thereof. The screw threads 1112a of the screw body 1112 are engaged with the guide member 1200 and, during the rotation of the screw 1110, transmit a rotational force of the screw to the guide member 1200. The rotational force of the screw that is transmitted to the guide member 1200 is converted into a driving force for linear displacement between the housing 1120 and the guide member 1200.

The housing 1120 rotatably accommodates the screw head 1111. The screw body 1112 of the screw 1110 is screw-coupled to the guide member 1200, and when rotation of the screw occurs due to a driving tool (not illustrated) coupled to the screw head 1111, the housing 1120 and the guide member 1200 approach each other or move away from each other.

In the intervertebral fusion cage 1000 according to one embodiment of the present invention, the housing 1120 may include a housing body 1121, a screw head arrangement portion 1122, a threshold torque setting member arrangement portion 1123, a separation preventing member arrangement portion 1124, a guide hole 1125, a first connecting portion 1126, and a plate portion 1127.

The housing body 1121 has the shape of a box that is vertically penetrated. The vertically penetrated portion of the housing body 1121 may be filled with a bone graft material. A left-right width of the housing body 1121 may correspond to a left-right width of a vertically penetrated portion of a guide body 1210 of the guide member 1200 which will be described below.

The screw head arrangement portion 1122 is formed to pass through the housing body 1121 in a front-rear direction. More specifically, the screw head arrangement portion 1122 is formed to pass through a front wall 1121a of the housing body 1121 in the front-rear direction. In a state in which the screw head 1111 is disposed at the screw head arrangement portion 1122, the screw body 1112 may protrude to the front of the housing body 1121.

The threshold torque setting member arrangement portion 1123 is formed in the housing body 1121 for the threshold torque setting member 1130 to be disposed therein. More specifically, the threshold torque setting member arrangement portion 1123 may be formed at the front wall 1121a of the housing body 1121. In one embodiment of the present invention, the threshold torque setting member arrangement portion 1123 is formed to surround the screw head arrangement portion 1122 in the circumferential direction. Also, the threshold torque setting member arrangement portion 1123 has the shape of a slot passing through both sides of the housing body 1121 for the threshold torque setting member 1130 to be disposed to pass through a side surface of the front wall 1121a of the housing body 1121.

The separation preventing member arrangement portion 1124 is formed in the housing body 1121 for the separation preventing member 1140 to be disposed therein. In one embodiment of the present invention, the separation preventing member arrangement portion 1124 is formed as a through-hole passing through both sides of the housing body 1121. More specifically, the separation preventing member arrangement portion 1124 passes through both sides of the front wall 1121a of the housing body 1121, and at least a portion of the separation preventing member 1140 is formed to be inserted into the second groove 1111c of the screw head 1111.

The guide hole 1125 is formed to pass through a rear wall 1121b of the housing body 1121 in the front-rear direction to allow a driving tool (not illustrated) for rotating the screw to pass through the vertically penetrated portion of the housing body 1121 and reach the screw head 1111. The driving tool may reach the screw head 1111 through the guide hole 1125.

The first connecting portion 1126 is formed at the housing body 1121 for the plate 1300 to be movably connected in the vertical direction. In one embodiment of the present invention, the first connecting portion 1126 is provided at left and right sidewalls 1121c of the housing body 1121. The first connecting portion 1126 is engaged with a second connecting portion 1340 of the plate 1300 which will be described below. For example, the first connecting portion 1126 may include a shape of a groove recessed in the vertical direction.

The plate portion 1127 is connected to a lower side of the housing body 1121. The plate portion 1127 may be disposed opposite to the plate 1300 which will be described below. The plate portion 1127 may extend to the front, rear, and both sides of the housing body 1121. Accordingly, the plate portion 1127 may form a lower surface of the intervertebral fusion cage 1000. Meanwhile, a central portion of the plate portion 1127 may have a vertically penetrated form to communicate with the vertically penetrated portion of the housing body 1121. Also, at both sides of the plate portion 1127, a guide groove 1127a may be provided from a corner toward the threshold torque setting member arrangement portion 1123 to guide insertion of the threshold torque setting member 1130 into the threshold torque setting member arrangement portion 1123.

The threshold torque setting member 1130 is disposed in the housing 1120, prevents rotation of the screw head 1111 with torque less than a threshold torque set on the screw head 1111, and allows the rotation of the screw head 1111 in a case where torque greater than or equal to the threshold torque is applied. In one embodiment of the present invention, the threshold torque setting member 1130 may, while inserted into the first grooves 1111a of the screw head 1111, suppress the rotation of the screw head 1111 before the set threshold torque is applied and may be separated from the first grooves 1111a and allow the rotation of the screw head 1111 due to the first protruding portion 1111b adjacent thereto in the case where the torque greater than or equal to the threshold torque is applied.

The threshold torque setting member 1130 may include a member body 1131 disposed to surround at least a portion of a circumference of the screw head 1111 and a catching portion 1132 protruding from the member body 1131 toward the screw head 1111 in order to be inserted into the first grooves 1111a. For example, the member body 1131 may be disposed to surround about half of the screw head 1111 in the circumferential direction thereof, and the catching portion 1132 may protrude from one side end of the member body 1131 toward the screw head 1111. In relation to this, in the case where the torque greater than or equal to the threshold torque is applied to the screw 1110, the member body 1131 may be elastically deformed.

The separation preventing member 1140 is disposed to be fixed to the housing 1120 while inserted into one portion of the second groove 1111c and prevents the screw 1110 from being separated from the housing 1120. In one embodiment of the present invention, the separation preventing member 1140 may be formed in the shape of a pin. More specifically, in a state in which the separation preventing member 1140 is inserted into the separation preventing member arrangement portion 1124 formed as the through-hole passing through both sides of the housing body 1121, at least a portion of the separation preventing member 1140 may be inserted into the second groove 1111c of the screw head 1111. Also, the separation preventing member 1140 may be disposed perpendicular to the screw 1110.

FIG. 8 is a view illustrating a driving state of the screw driving module of the intervertebral fusion cage according to one embodiment of the present invention.

Referring to FIG. 8, in a state in which the catching portion 1132 of the threshold torque setting member 1130 is inserted into the first grooves 1111a, the rotation of the screw 1110 is limited by the catching portion 1132 before the torque greater than or equal to the threshold torque is applied. This is because the first protruding portion 1111b adjacent to the first grooves 1111a, into which the catching portion 1132 is inserted, is caught at the catching portion 1132 and suppresses the rotation of the screw. Meanwhile, in the case where the torque greater than or equal to the threshold torque is applied to the screw 1110, the first protruding portion 1111b of the screw head 1111 pushes the catching portion 1132 radially outward from the first grooves 1111a. Accordingly, as the screw head 1111 rotates, the screw 1110 rotates. The guide member 1200 engaged with the screw 1110 may move according to the rotation of the screw 1110.

The screw body 1112 of the screw 1110 is screw-rotatably coupled to the guide member 1200. The guide member 1200 is displaced forward or rearward while moving relative to the screw driving module 1100, and displacement of the plate 1300 occurs according to changes in positions of the guide member 1200 and the screw driving module 1100 relative to each other. The guide member 1200 may include a guide body 1210, a front guide portion 1220, a rear guide portion 1230, a screw hole 1240, and a rear hole 1250.

The guide body 1210 is formed to be vertically penetrated. The guide body 1210 may have the shape of a frame whose central portion is penetrated. Also, the guide body 1210 may have a quadrangular shape as a whole. The housing body 1121 of the housing 1120 of the screw driving module 1100 is disposed inside the guide body 1210, and according to rotation of the screw 1110 rotatably coupled to the housing 1120, the housing 1120