JP5517053B2 - Fixed structure and bone plate kit - Google Patents

Description

  The present invention relates to a fixing structure and a bone plate kit.

  2. Description of the Related Art Conventionally, as a bone plate fixing structure, a plate hole having a taper screw and a plate hole having three dents spaced apart in the circumferential direction has been adopted (see, for example, Patent Document 1). . According to this fixing structure, the screw is inclined in an arbitrary direction with respect to the bone plate by fastening male screws provided on the screw head to different screw threads at three tapered screw portions separated from each other by the recess. It can be fixed.

Special table 2007-506450 gazette

  However, in the fixing structure of Patent Document 1, the meshing between the taper screw provided on the bone plate and the male screw provided on the head of the screw worsens as the inclination angle of the screw with respect to the bone plate increases, and the fixing force decreases. There is an inconvenience of going. In particular, in the fixing structure of Patent Document 1, only a single thread is securely engaged in a region less than one third of the entire circumference, and the femur and tibia to which a relatively large load is applied. There is a problem that it cannot be applied to fixing.

  The present invention has been made in view of the above-described circumstances, and can fix the screw fixed to the object in a state inclined with respect to the object to be fixed to the object to be fixed more reliably. It aims at providing the fixation structure and bone plate kit which can be applied also to a site | part with a high load.

In order to achieve the above object, the present invention provides the following means.
The present invention has a pilot hole provided in an object to be fixed to the surface of a target object, a female screw formed around the pilot hole and fastened with a plug on an inner peripheral surface, and a bottom surface. A counterbore having a cylindrical inner surface shape or an inner spherical shape, a head that is provided on a screw that passes through the pilot hole and is fastened to the object , and has a shoulder that is complementary to the bottom surface of the counterbore , A spacer sandwiched between the head and the plug, the spacer is formed in a wedge shape having oppositely inclined end faces, and a plurality of wedge-shaped spacers are arranged in the thickness direction; Provide a fixed structure.

  According to the present invention, when the object to be fixed is disposed on the surface of the object and the screw is fastened to the object through the pilot hole provided in the object to be fixed, the shoulder portion of the head provided on the screw Hits the bottom of the counterbore provided around the pilot hole. The bottom surface of the counterbore has a cylindrical inner surface shape or an inner spherical surface shape, and the shoulder portion has a shape complementary to the bottom surface of the counterbore, so that the screw is in a state where the shoulder portion and the bottom surface of the counterbore are in close contact with each other. The angle with respect to the fixed object can be changed while maintaining. For example, a wedge-shaped spacer is sandwiched between the screw head and the plug, or an inclined surface is provided on the end surface of the head, and the plug is fastened to the female screw provided on the inner peripheral surface of the counterbore. Thus, the screw can be fixed to the fixed object by pressing the head with the plug.

In this case, according to the present embodiment, the plug is securely engaged with the female screw provided on the inner peripheral surface of the counterbore over the entire circumference and over the plurality of screw threads, so that a sufficient fixing force can be obtained. it can. That is, the screw fastened to the target object in a state inclined with respect to the fixed object can be reliably fixed to the fixed object in the inclined state by the plug.
In addition, a spacer sandwiched between the head and the plug is provided, and the spacer is formed in a wedge shape having both end surfaces inclined relatively, so that the spacer is inclined between the head and the plug. The screw fastened to the target object can be reliably fixed to the fixed object in the inclined state by the plug only by adjusting the direction and pinching the plug. It is sufficient to prepare a screw having a head whose end face is perpendicular to the longitudinal axis, and by selecting a wedge-shaped spacer having a different inclination angle, the inclination angle of the screw with respect to the object to be fixed is appropriately changed. can do.
Furthermore, by arranging a plurality of spacers in the thickness direction, the inclination angle of the screw can be continuously changed by changing the relative rotation angle of the plurality of spacers stacked in the thickness direction. it can. According to this structure, the inclination angle of the screw can be set more freely.

In the above invention, the object may be a bone, and the object to be fixed may be a bone plate.
In this way, when the bone plate is placed on the surface of the bone and the screw is fastened to the bone through the pilot hole provided in the bone plate, the shoulder portion of the head provided in the screw becomes the pilot hole. It hits the bottom of the counterbore provided around. Even if the screw is fastened in a direction inclined with respect to the bone plate, the shoulder portion of the head and the bottom surface of the counterbore having mutually complementary shapes such as the cylindrical inner surface and the cylindrical surface, and the inner spherical surface and the spherical surface are mutually connected. The screw can be fixed to the bone plate by a plug.

  That is, according to the present embodiment, the plug is securely engaged with the female screw provided on the inner peripheral surface of the counterbore over the entire circumference and over the plurality of screw threads, so that a sufficient fixing force can be obtained. Thereby, the screw fastened to the bone in an inclined state with respect to the bone plate can be reliably fixed to the bone plate by the plug in the inclined state.

Further, in the above invention, the spacer is provided with a protrusion protruding outward in the radial direction, and the counterbore has a groove for receiving the protrusion and locking the rotation of the spacer in the circumferential direction with respect to the counterbore. It may be provided.
By doing this, when the plug is fastened to the counterbore female screw with the protrusion provided on the spacer inserted in the counterbore groove, the plug is fastened without rotating the spacer in the counterbore. I can go. Thereby, since it is not necessary to change the direction of the inclined surface provided in the spacer, the screw can be fixed in a state where the screw is inclined in a desired direction.

In the above invention, the counterbore is provided with a protrusion projecting radially inward, and the groove accommodates the protrusion in the spacer and locks the rotation of the spacer in the circumferential direction with respect to the counterbore. May be provided.
By doing so, when the plug is fastened to the counterbore female thread with the groove provided in the spacer aligned with the counterbore projection, the plug is fastened without rotating the spacer in the counterbore. Can continue. Thereby, since it is not necessary to change the direction of the inclined surface provided in the spacer, the screw can be fixed in a state where the screw is inclined in a desired direction.

Moreover, in the said invention, the said groove | channel may be provided with two or more at intervals in the circumferential direction.
By doing in this way, the direction of the inclined surface provided in the spacer can be changed by changing the groove into which the protrusion is inserted. The screw can be fixed in a state where it is tilted in various directions by simply selecting a groove into which the projection is inserted in accordance with the direction in which the screw is to be tilted.

The present invention is also provided with a prepared hole disposed along the surface of the bone, and a counterbore formed around the prepared hole and having an internal thread on the inner peripheral surface, and the bottom surface of the counterbore has a cylindrical inner surface shape or A bone plate having an inner spherical shape, a head having a shoulder portion complementary to the bottom surface of the counterbore, and a screw that passes through a pilot hole of the bone plate and fixes the bone plate to the bone; A plug that is fastened to the female screw and fixes the screw, a spacer that is sandwiched between the head and the plug, and that is formed in a wedge shape with both end faces relatively inclined , and the spacer is attached to the plug A bone plate kit is provided that includes a temporary fixing means that is held in a state and allows relative rotation of the spacer with respect to the plug when the plug is fastened .

According to the present invention, when the plate is arranged along the surface of the bone, and the screw inclined at a desired angle with respect to the plate is passed through the lower hole of the plate and fastened to the bone, The provided shoulder portion presses the bottom face of the counterbore provided around the pilot hole, whereby the plate can be fixed to the surface of the bone. The bottom face of the counterbore has a cylindrical inner surface shape or an inner spherical surface shape, and has a shape complementary to the shoulder part, so that the shoulder part and the bottom face of the counterbore are in close contact regardless of the inclination angle of the screw with respect to the plate. Can be made. Then, in a state where the inclined surface provided on the head of the screw is arranged so as to be orthogonal to the axis of the pilot hole, a spacer having an adjusted inclination direction is arranged between the head and the plug so that the inner surface of the counterbore By fastening the plug to the provided female screw, the screw can be pressed by the plug through the spacer, and the screw can be fixed in an inclined state with respect to the plate.
Further, by providing the temporary fixing means, it is possible to handle the plug and the spacer in an integrated state in which the plug and the spacer are temporarily fixed, thereby improving the handleability. When the plug with spacer is fastened to the counterbore female screw, the spacer is temporarily fixed in the middle of fastening, and the plug can be fastened while the spacer is kept in close contact with the end face of the screw head. it can.

  In the above invention, the spacer is provided with a protrusion protruding outward in the radial direction, and the counterbore is provided with a groove for receiving the protrusion and locking the circumferential rotation of the spacer with respect to the counterbore. It may be.

In the above invention, the counterbore is provided with a protrusion projecting radially inward, and the groove accommodates the protrusion in the spacer and locks the rotation of the spacer in the circumferential direction with respect to the counterbore. May be provided.
Moreover, in the said invention, the said groove | channel may be provided with two or more at intervals in the circumferential direction.
In the above invention, a plurality of wedge-shaped spacers may be provided so as to overlap in the thickness direction.

In the above invention, the temporary fixing means may be an adhesive.
The plug and the spacer are simply temporarily fixed by the adhesive, and when the plug is fastened, the temporary fixing by the adhesive can be released to allow independent rotation of the plug.

Further, in the above invention, the temporary fixing means has a cylindrical convex portion provided at the center of the end face of the plug and an inner diameter dimension slightly smaller than the outer diameter dimension of the convex section provided on the spacer. The spacer may be formed in a C-ring shape by cutting in a radial direction from the outer edge to the fitting hole.
By doing in this way, the fitting hole of a C-ring-shaped spacer can be fitted to the convex part of the end surface of a plug, and a spacer can be temporarily fixed to a plug by friction.

Moreover, in the said invention, the small diameter part of the outer diameter dimension slightly smaller than the internal diameter dimension of the fitting hole of the said spacer may be provided in the base end side of the said convex part.
By doing in this way, a small diameter part can be used as relief and a spacer can be stuck to the end face of a plug.

  ADVANTAGE OF THE INVENTION According to this invention, the screw fixed to the target object in the state inclined with respect to the to-be-fixed object can be fixed to a to-be-fixed object more reliably, and can be applied also to a site | part with a high load. There is an effect.

It is a partial longitudinal cross-sectional view which shows the fixation structure and bone plate kit which concern on one Embodiment of this invention. It is a top view which shows the spot facing provided in the bone plate of the bone plate kit of FIG. It is a perspective view which shows the spacer of the bone plate kit of FIG. FIG. 2 is a partially exploded longitudinal sectional view for explaining an operation of fixing a bone plate to a bone using the bone plate kit of FIG. 1. It is a partial longitudinal cross-sectional view which shows the modification of the plug of the bone plate kit of FIG.

A fixing structure and a bone plate kit according to an embodiment of the present invention will be described below with reference to the drawings.
The fixing structure according to this embodiment is a fixing structure of the bone plate 1. As shown in FIG. 1, the bone plate kit 2 according to this embodiment includes a bone plate 1 disposed along the surface of the bone A, a screw 3 that fixes the bone plate 1 to the bone A, and a screw 3. Are attached to the bone plate 1, and a spacer 5 is sandwiched between the plug 4 and the screw 3.

The fixing structure according to this embodiment includes a pilot hole 6 provided in the bone plate 1, a counterbore 7 provided in the pilot hole 6, and a head 8 provided in the screw 3.
That is, the counterbore 7 is provided around the pilot hole 6 and its bottom surface 7a has an inner spherical shape. As shown in FIG. 2, a female screw 7 b is formed on the inner peripheral surface of the spot facing 7. The counterbore 7 is provided with two grooves 9 extending in the longitudinal direction at intervals in the circumferential direction.

The screw 3 includes a screw portion 3 a having an outer diameter slightly smaller than that of the pilot hole 6 that can penetrate the pilot hole 6.
The head 8 is disposed at the end of the screw portion 3a and has a larger outer diameter than the screw portion 3a. The head 8 has a shoulder portion 8a having a shape complementary to the bottom surface 7a of the spot facing 7, that is, a substantially hemispherical shape.

Further, the end face of the head 8 is substantially orthogonal to the longitudinal axis of the screw portion 3a, and a hexagonal hole 10 for inserting a tool when the screw 3 is rotated around the longitudinal axis and fastened to the bone A, and a plug 4 is provided with a recess 11 into which the tip of 4 is inserted.
The plug 4 includes a male screw 4 a that is fastened to a female screw 7 b provided on the inner peripheral surface of the counterbore 7, and a convex portion 4 b that is inserted into the concave portion 11 of the head 8 of the screw 3.

  As shown in FIG. 3, the spacer 5 is an annular member having a fitting hole 5 a that fits into the convex portion 4 b of the plug 4 in a tight fit state, and a part thereof is cut away. It is formed in a substantially C shape. By providing the notch 5b, the spacer 5 is adapted to tighten the convex portion 4b of the plug 4 fitted in the fitting hole 5a due to its elasticity. When a torque larger than the static friction force between the plug 4 and the spacer 5 is applied, both are rotated relative to each other.

Further, on the outer surface of the spacer 5, a protrusion 5 c that extends radially outward in a part of the circumferential direction and engages with the groove 9 of the counterbore 7 is provided.
The spacer 5 is formed in a substantially wedge shape having an inclined surface 5d whose other surface is inclined with respect to one surface by gradually changing the thickness dimension in one direction.

The operation of the fixing structure and the bone plate kit 2 according to this embodiment configured as described above will be described.
In order to fix the bone plate 1 to the surface of the bone A using the fixing structure and the bone plate kit 2 of the present embodiment, the bone plate 1 is arranged along the surface of the bone A and provided on the bone plate 1. A tool (not shown) is inserted into the hexagonal hole 10 of the screw 3 disposed through the pilot hole 6, and the screw 3 is rotated around the longitudinal axis, whereby the screw 3 is fastened to the bone A.

At this time, the screw 3 is passed through the pilot hole 6 and fastened so that the screw 3 has a predetermined inclination angle with respect to the bone plate 1, that is, the wedge-shaped inclination angle of the spacer 5 to be used. Go.
When the fastening of the screw 3 to the bone A proceeds and the shoulder portion 8a of the head 8 abuts against the bottom surface 7a of the counterbore 7, the bottom surface 7a of the counterbore 7 is pressed by the shoulder portion 8a, whereby the bone plate 1 is pressed in the direction of the surface of the bone A, and the bone plate 1 is fixed to the bone A.

The bottom surface 7a of the counterbore 7 is formed in an inner spherical shape, and the shoulder 8a of the screw 3 has a hemispherical shape complementary to the bottom surface 7a of the counterbore 7, so that the inclination angle of the screw 3 with respect to the bone plate 1 is increased. Regardless, the shoulder 8 a of the screw 3 can be brought into close contact with the bottom surface 7 a of the counterbore 7.
In this state, the end surface 8 b of the head 8 of the screw 3 is arranged to be inclined at a predetermined inclination angle with respect to the axis of the counterbore 7.

  Thereafter, as shown in FIG. 4, the plug 4 in a state in which the protrusion 4 b is fitted into the fitting hole 5 a of the spacer 5 and integrated with the spacer 5 is attached to the female screw 7 b provided on the counterbore 7. Conclude. At this time, the projection 5c provided on the spacer 5 is inserted so as to be disposed in the groove 9 provided on the spot facing 7, and then fastening is started. When the plug 4 is rotated by applying torque, the rotation of the spacer 5 is limited by the protrusion 5c engaged with the groove 9, so that torque is applied between the plug 4 and the spacer 5, and the torque is the static friction force of both. Is exceeded, the plug 4 is rotated with respect to the spacer 5.

Since the protrusion 5c provided on the spacer 5 is accommodated in the groove 9, the spacer 5 is pushed in the depth direction while keeping its rotational position constant with respect to the counterbore 7, so that the screw 3 The head 8 is brought into close contact with the end surface 8b.
Since the spacer 5 is formed in a wedge shape having the same inclination angle as that of the end face 8 b of the head 8, when the spacer 5 is brought into close contact with the end face 8 b of the head 8, the inclination of the end face 8 b of the head 8 is absorbed. Are arranged in a direction perpendicular to the axis of the spot facing 7.

  When the plug 4 is further tightened in this state, a pressing force is applied in the axial direction from the plug 4 to the spacer 5 together with the fastening, and the head 8 of the screw 3 that is in close contact with the spacer 5 is axially moved. Will come to press. Thereby, the screw 3 is fixed to the bone plate 1 in an inclined state with respect to the bone plate 1.

  As described above, according to the fixing structure and the bone plate kit 2 according to this embodiment, the plug 4 is firmly fastened to the female screw 7b of the counterbore 7, so that the screw 3 can be fixed to the bone plate 1 with a high fixing force. . Compared with the case where the screw 3 is inclined with respect to the bone plate 1 by mistaking the screw 3 and the female screw 7b as in the prior art, there is an advantage that a high fixing force can be generated. Thereby, it can apply also for fixation of the femur and the tibia to which a comparatively big load is applied.

  Further, according to the fixing structure and the bone plate kit 2 according to this embodiment, the gap between the screw 3 and the plug 4 is filled by the wedge-shaped spacer 5, so that the screw 3 does not wobble with respect to the bone plate 1. Can be fixed. Further, by changing the inclination angle of the spacer 5 to be used, various inclination angles of the screw 3 with respect to the bone plate 1 can be set.

  Further, by engaging the protrusion 5 c provided on the spacer 5 with the groove 9 provided on the counterbore 7, it is possible to prevent the spacer 5 from being displaced during fastening of the plug 4. Further, since the grooves 9 are provided at two locations in the circumferential direction, the inclination direction of the screw 3 with respect to the bone plate 1 can be changed by changing the grooves 9 with which the protrusions 5c are engaged.

  Further, in this embodiment, since the notch 5b is provided in the fitting hole 5a provided in the spacer 5 to form a substantially C shape, the protrusion 4b of the plug 4 is tightened by the elasticity of the spacer 5, and the spacer 5 is The plug 4 can be integrated. Thereby, the plug 4 integrated with the spacer 5 can be handled as a single component, and the handleability can be improved.

  In the present embodiment, the grooves 9 are provided at two locations at intervals in the circumferential direction. Alternatively, the grooves 9 may be provided at one location, or at three or more locations. If the spacer 5 can be fixed to the end surface 8a of the head 8 of the screw 3 so as not to rotate, the groove 9 and the protrusion 5c need not be provided.

  Further, the groove 9 is provided on the inner peripheral surface of the counterbore 7 and the protrusion 5c is provided on the spacer 5. Instead, the spacer 5 is provided with a protrusion protruding radially inward, A notch for engaging the protrusion may be provided. In this case, it is preferable to provide a plurality of notches provided in the spacer 5 at intervals in the circumferential direction.

  In the present embodiment, the gap between the end surface 8a of the head 8 of the screw 3 and the plug 4 is filled using a single spacer 5 having an inclination angle that matches the inclination angle of the screw 3. Instead of this, two wedge-shaped spacers 5 may be used in an overlapping manner. By doing in this way, an inclination angle can be changed continuously by changing the relative phase of the two spacers 5. Therefore, the inclination angle of the screw 3 with respect to the bone plate 1 can be continuously adjusted, and the bone plate 1 can be more securely fixed by selecting the angle of the screw 3 more flexibly. Three or more spacers 5 may be used.

  Further, in this embodiment, the spacer 5 is integrated with the plug 4 by tightening the convex portion 4b of the plug 4 by the fitting hole 5a of the spacer 5, but instead of this, as shown in FIG. Alternatively, a small diameter portion 4c having an outer diameter smaller than the fitting hole 5a of the spacer 5 may be provided on the convex portion 4b, and the spacer 5 may be fitted with play in the small diameter portion 4c. Accordingly, there is an advantage that the plug 4 and the spacer 5 are integrally formed, the free rotation of the spacer 5 with respect to the plug 4 is allowed, and the handleability can be further improved.

  Further, instead of attaching the spacer 5 to the plug 4 by friction or fitting the spacer 5 to the small diameter portion 4c, the spacer 5 may be attached by an adhesive. The adhesive preferably has an adhesive strength that allows the plug 4 to freely rotate with respect to the spacer 5 by releasing the adhesive state when a predetermined torque is applied between the spacer 5 and the plug 4. .

  In addition, the inclined surface 5d is configured by the spacer 5, but instead, the inclined surface 5d may be integrally provided on the end surface 8b of the head 8 of the screw 3. Alternatively, the spacer 5 may be temporarily fixed to the end surface 8b of the head 8 of the screw 3 with an adhesive. In this case, the protrusion 5 c is not provided on the spacer 5.

In the present embodiment, the fixing structure of the bone plate 1 and the bone plate kit 2 having the fixing structure have been described as examples. However, the present invention is not limited to this, and any other object to be fixed is a target. You may decide to utilize as a fixing structure in the case of fixing to the surface of this.
In addition, although the inner spherical surface is illustrated as the bottom surface of the spot facing 7, a cylindrical inner surface may be employed instead. In this case, the shoulder 8a of the head 8 only needs to have a shape complementary to the bottom surface 7a of the cylindrical inner surface, that is, a shape having a semi-cylindrical surface. By doing in this way, the angle of the screw 3 with respect to the bone plate 1 can be changed in one direction along the circumferential direction of the cylindrical inner surface.

  Moreover, although the case where the axis of the screw 3 is tilted and fixed with respect to the axis of the counterbore 7 is illustrated, instead of this, the axis of the screw 3 is arranged without being tilted with respect to the axis of the counterbore 7. You can also. In that case, a spacer 5 having no inclination may be used. Alternatively, the screw 3 may be pressed directly by the plug 4 without using the spacer 5.

A bone (object)
1 Bone plate (fixed object)
3 Screw 4 Plug 4b Protruding part 4c Small diameter part 5 Spacer 5a Fitting hole (temporary fixing means)
5b Notch (cut)
5c Projection 5d Inclined surface 6 Pilot hole 7 Counterbore 7a Bottom surface 7b Female screw 8 Head 8a Shoulder 8b End face 9 Groove

Claims (13)

A pilot hole provided in an object to be fixed to the surface of the object;
A counterbore having a female thread that is formed around the pilot hole and to which the plug is fastened to the inner peripheral surface, and the bottom surface has a cylindrical inner surface shape or an inner spherical surface shape;
A head provided on a screw that passes through the pilot hole and is fastened to the object ;
A spacer sandwiched between the head and the plug;
The spacer is formed in a wedge shape having relatively inclined end faces;
A fixing structure in which a plurality of wedge-shaped spacers are stacked in the thickness direction .   The fixing structure according to claim 1, wherein the object is a bone and the object to be fixed is a bone plate. The spacer is provided with a protrusion protruding radially outward,
The fixing structure according to claim 1 , wherein the counterbore is provided with a groove that accommodates the protrusion and stops circumferential rotation of the spacer with respect to the counterbore. The counterbore is provided with a protrusion protruding radially inward,
The fixing structure according to claim 1 , wherein the spacer is provided with a groove that accommodates the protrusion and stops circumferential rotation of the spacer with respect to the counterbore. The fixing structure according to claim 3 or 4 , wherein a plurality of the grooves are provided at intervals in the circumferential direction. A bone disposed along the surface of the bone, provided with a pilot hole and a counterbore formed around the pilot hole and having an internal thread on the inner peripheral surface, and the bottom surface of the counterbore has a cylindrical inner surface shape or an inner spherical surface shape Plates,
A screw having a shoulder having a shape complementary to the bottom surface of the counterbore, passing through a pilot hole in the bone plate, and fixing the bone plate to the bone;
A plug fastened to the female screw to fix the screw;
A spacer sandwiched between the head and the plug and formed in a wedge shape in which both end faces are relatively inclined ;
A bone plate kit comprising: temporary fixing means for holding the spacer attached to the plug and allowing relative rotation of the spacer with respect to the plug when the plug is fastened . The spacer is provided with a protrusion protruding radially outward,
The bone plate kit according to claim 6 , wherein the counterbore is provided with a groove that accommodates the protrusion and stops circumferential rotation of the spacer with respect to the counterbore. The counterbore is provided with a protrusion protruding radially inward,
The bone plate kit according to claim 6 , wherein the spacer is provided with a groove that accommodates the protrusion and locks the spacer in rotation in the circumferential direction with respect to the counterbore. The bone plate kit according to claim 7 or 8 , wherein a plurality of the grooves are provided at intervals in the circumferential direction. The bone plate kit according to claim 7 , comprising a plurality of wedge-shaped spacers stacked in the thickness direction. The bone plate kit according to claim 6 , wherein the temporary fixing means is an adhesive. The temporary fixing means includes a cylindrical convex portion provided in the center of the end face of the plug, and a fitting hole provided in the spacer and having an inner diameter dimension slightly smaller than an outer diameter dimension of the convex section,
The bone plate kit according to claim 6 , wherein the spacer is formed in a C-ring shape by cutting in a radial direction from the outer edge to the fitting hole. The bone plate kit according to claim 12 , wherein a small-diameter portion having an outer diameter slightly smaller than the inner diameter of the fitting hole of the spacer is provided on the base end side of the convex portion.

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