JP3875812B2 - Bone filling spacer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a bone filling spacer.
[0002]
[Prior art]
One of surgical operations for spinal diseases such as intervertebral disc disorders and ligament ossification is called interbody fusion. This is an operation in which an intervertebral disc is removed, and then a part of a vertebral body is incised, separated, and deleted, the affected part is treated, and then a transplanted bone is transplanted into the affected part.
[0003]
As bone grafts used for such operations, metal-made artificial bones are known.
However, since such artificial bones are different in rigidity from autologous bones, when artificial bones are used, the upper and lower vertebral bodies in the vicinity of the affected area are compressed after surgery, and the vertebral bodies are collapsed in patients with poor bone quality such as osteoporosis. There is a fear. In addition, when an artificial bone is used, if the artificial bone is inserted poorly, the artificial bone itself may be damaged or fall off.
[0004]
Further, autologous bones of patients such as iliac bones are widely used as transplanted bones other than artificial bones used in such operations.
However, when the autologous bone was collected, there was a case where pain occurred in the bone collecting portion later. In addition, there is a case where the autologous bone is not sufficiently large. If autologous bone that does not have such a sufficient size is used for transplantation, the spine may be deformed after surgery.
[0005]
Further, as shown in FIG. 7, a vertebral bone fragment 900 separated from a vertebral body may be used as a transplanted bone. In this case, the bone piece 900 of the vertebral body incised and separated from the vertebral body 901 is inserted between the vertebral bodies 901 again as a transplanted bone.
[0006]
In this technique, the separated vertebral body is returned to the affected area again, so that it is not necessary to remove the bone from another place of the patient, and there is no problem such as pain in the bone collecting part.
However, in practice, the separated vertebral body cannot be directly returned to the surgical site. This is because a gap is created between the vertebral body bone piece 900 and the vertebral body 901 by the amount of the removed intervertebral disc or the cutting margin.
[0007]
Therefore, conventionally, as shown in FIG. 7, the vertebral body piece 900 is placed between the vertebral bodies 901 so that the long axis of the vertebral body piece 900 cut into a rectangular parallelepiped coincides with the axis of the vertebral body 901. It was inserted.
However, when the vertebral body piece 900 is inserted between the vertebral bodies 901 in this way, the gap between the vertebral bodies 901 formed by surgery cannot be completely closed. For this reason, after the operation, the bone piece 900 of the vertebral body may be displaced at the operation site, resulting in a kyphosis deformity or the like in the spinal column. In the surgical site, the intervertebral disc is removed, so that the support, mobility, and buffering action of the spinal column that the intervertebral disc has are lost. For this reason, after the operation, there is a possibility that the mobility of the spine is limited, or the bone piece 900 of the transplanted vertebral body or the upper and lower vertebral bodies are crushed by a load applied to the spine.
[0008]
On the other hand, an operation method called intervertebral disk replacement is known. This is because the intervertebral disc and the intervertebral disc united from the vertebral body are cut and separated from the vertebral body, and then the affected part is treated. How to insert.
[0009]
In this method, since the transplanted bone is transplanted while the intervertebral disc is preserved, the original function of the intervertebral disc is unlikely to be impaired. For this reason, after the operation, the mobility of the spine is not easily restricted, and the buffering action against the load is hardly impaired. That is, it is expected that the original function of the spine is not easily impaired.
[0010]
However, actually, when the separated bone fragment is returned to the surgical site as it is, a kyphosis deformity or the like may occur in the spinal column. This is because a gap is formed by the width of the margin for cutting and separating.
[0011]
[Problems to be solved by the invention]
An object of the present invention is to provide a bone replacement spacer that can securely fix a transplanted bone to an operation site and can perform intervertebral disk replacement and the like so as not to impair spinal support, mobility, and buffering action. Is to provide.
[0012]
[Means for Solving the Problems]
Such an object is achieved by the present inventions (1) to (8) below.
[0014]
(1) A bone fragment in which a part of a vertebral body is joined to the top and bottom of an intervertebral disc is cut out from the surgical site and inserted into the gap formed in the surgical site together with the bone fragment. Bone replacement spacer used for
The bone filling spacer has a plate shape or a block shape, and a plurality of grooves into which a linear body for fixing the bone filling spacer to the bone piece is inserted on a surface facing the surface contacting the bone piece, The depth of the grooves along one direction of the lattice is different from the depth of the grooves along the other direction of the lattice, and rises at the portion where the linear bodies inserted into these grooves intersect. And the linear body is formed so as not to protrude from the groove, and is inserted into the gap while being inserted into the bone fragment and fixed with the linear body. A bone repair spacer, wherein the surface on which the surface is formed abuts against the cut surface of the gap and the groove exhibits an anchor effect.
[0016]
(2) The bone filling spacer according to (1), wherein a cross section of the groove has a U shape.
Thereby, the strength of the bone filling spacer is improved.
[0022]
(3) The bone filling spacer according to (1) or (2), wherein the bone piece is sandwiched between at least two bone filling spacers.
As a result, the bone graft can be more securely fixed to the surgical site.
[0023]
(4) The bone replacement spacer according to any one of (1) to (3), wherein the bone material is made of a ceramic material.
Thereby, the bone filling spacer excellent in workability can be obtained.
[0024]
(5) The bone graft spacer according to (4), wherein the ceramic material is made of a calcium phosphate compound.
Thereby, the bone filling spacer which has the outstanding biocompatibility can be obtained.
[0025]
(6) The bone filling spacer according to (5), wherein the calcium phosphate compound has a Ca / P ratio of 1.0 to 2.0.
Thereby, the bone filling spacer which has the more excellent biocompatibility can be obtained.
[0026]
(7) The bone grafting spacer according to (5) or (6), wherein the calcium phosphate compound is hydroxyapatite.
Thereby, a bone filling spacer having particularly excellent biocompatibility can be obtained.
[0027]
(8) The bone replacement spacer according to any one of (4) to (7), wherein the ceramic has a porosity of 0 to 70%.
This promotes the healing of the bone tissue to the bone filling spacer.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.
FIG. 1 is a perspective view showing an embodiment of the bone filling spacer of the present invention, and FIG. 2 is a plan view, a front view, and a side view of the bone filling spacer shown in FIG. 2A is a plan view of the bone filling spacer, FIG. 2B is a side view, and FIG. 2C is a front view.
[0029]
As shown in these drawings, the bone filling spacer 1 of the present invention has, for example, a block shape (plate shape), and a plurality of grooves (on the one surface of the main body 2 forming the main part of the bone filling spacer 1). (Fixing means) 3 is formed.
[0030]
As shown in FIG. 6, the bone replacement spacer 1 is inserted into the vertebral body disc unit 10, and in this state, is inserted into the surgical site 15 together with the vertebral body disc unit 10. Hereinafter, for convenience of explanation, when the bone replacement spacer 1 is inserted into the vertebral disc unit 10, the surface of the bone replacement spacer 1 that contacts the vertebral disc unit 10 is referred to as a bone fragment contact surface 21, and the bone fragment contact surface. The surface facing 21 is called the vertebral body contact surface 22.
[0031]
The main body 2 constitutes a main part of the bone filling spacer 1 and has, for example, a block shape (plate shape). Further, the planar shape (planar shape) of the main body 2 is, for example, a substantially rectangular shape (quadrangle).
[0032]
A plurality of grooves 3 are arranged in a lattice pattern on the vertebral body contact surface 22 of the main body 2. By inserting a linear body 11 such as a thread into the groove 3 and binding it to the vertebral disc unit 10, the bone replacement spacer 1 can be fixed to the vertebral disc unit 10 (see FIG. 6). These grooves 3 have a concave curved surface, and the cross-sectional shape thereof is U-shaped. Thereby, when a pressure is applied from the vertebral body contact surface 22 side, the stress applied to the vicinity of the groove 3 can be suitably relaxed, and the bone filling spacer 1 is hardly broken. Further, the linear body 11 inserted into the groove 3 is also difficult to break.
[0033]
As shown in FIG. 2, the groove 3 along one direction of the lattice is formed substantially parallel to the long side of the vertebral body contact surface 22, and the groove 3 along the other direction of the lattice is the vertebral body. It is formed substantially parallel to the short side of the contact surface 22.
Hereinafter, the long side direction of the vertebral body contact surface 22 is referred to as an X direction, and the short side direction of the vertebral body contact surface 22 is referred to as a Y direction. The groove 3 formed substantially parallel to the long side of the vertebral body contact surface 22 is referred to as a groove 3X, and the groove 3 formed substantially parallel to the short side of the vertebral body contact surface 22 is referred to as a groove 3Y. These grooves 3X and 3Y are substantially orthogonal to each other.
[0034]
The grooves 3X and 3Y are equally arranged in the X direction and the Y direction of the vertebral body contact surface 22, respectively. As a result, when the bone replacement spacer 1 is fixed to the vertebral disc unit 10, the linear bodies 11 can be arranged in a balanced manner, and the stability of fixation is improved.
[0035]
The grooves 3X and 3Y have different depths. Specifically, the depth of the groove 3X is deeper than the depth of the groove 3Y. As a result, when the linear body 11 is inserted into the groove 3X and the groove 3Y, the linear body 11 is swelled by the intersection of the two linear bodies 11 at the intersection 31 of the groove 3X and the groove 3Y. You can prevent what you can do. For this reason, the linear body 11 inserted into the groove 3 is preferably prevented from protruding from the groove 3. Thereby, the linear body 11 protruding from the groove 3 is suitably prevented from rubbing against the vertebral body and the like, and the linear body 11 being disconnected.
[0036]
From the viewpoint of suitably obtaining such an effect, the difference between the depth of the groove (deep groove) 3X and the depth of the groove (shallow groove) 3Y is preferably about 0.1 to 0.5 mm. Thereby, it can prevent suitably that the linear body 11 can swell in the cross | intersection part 31, and it is also prevented suitably that the intensity | strength of the bone grafting spacer 1 falls by the one part groove | channel 3 becoming deep. The depth of the groove 3X and the groove 3Y may be the same.
[0037]
From the same viewpoint, the maximum depth of the groove 3 is preferably about 0.2 to 1 mm. Further, when the maximum depth of the groove 3 is D ₁ and the thickness of the main body 2 is T, D ₁ / T is preferably about 0.03 to 0.5. Thereby, it is prevented suitably that the linear body 11 protrudes from the groove | channel 3 while preventing the intensity | strength of the bone replacement spacer 1 falling.
[0038]
The number of grooves 3 is preferably about 2 to 10, and more preferably about 4 to 8. The number of grooves 3X and 3Y is preferably about 2 to 4 respectively. As a result, the bone replacement spacer 1 can be more reliably fixed to the vertebral body disc unit 10. In addition, the strength of the bone filling spacer 1 is also prevented from greatly decreasing.
The thickness T of the main body 2 is preferably about 2 to 6 mm. Thereby, the bone filling spacer 1 comes to exhibit the function as a spacer suitably, maintaining high intensity | strength.
Note that the lengths of the long side and the short side of the main body 2 (vertebral body contact surface 22) are appropriately determined based on the size of the vertebral body intervertebral disc unit 10 and the size of the gap 13 of the surgical section 15 described later. .
[0039]
Such bone filling spacer 1 is preferably made of a ceramic material as a constituent material. Since the ceramic material is excellent in workability, it is easy to adjust its shape, size, etc. by cutting using a lathe, drill or the like.
[0040]
Examples of the ceramic material include various ceramic materials, and bioceramics such as alumina, zirconia, and calcium phosphate compounds are particularly preferable. Among these, calcium phosphate compounds are particularly preferable as a constituent material of the bone grafting spacer 1 because they have excellent biocompatibility.
[0041]
Examples of the calcium phosphate compound include apatites such as hydroxyapatite, fluorapatite, and carbonate apatite, dicalcium phosphate, tricalcium phosphate, tetracalcium phosphate, octacalcium phosphate, and the like. A mixture of seeds or more can be used. Of these calcium phosphate compounds, those having a Ca / P ratio of 1.0 to 2.0 are preferably used.
[0042]
Of such calcium phosphate compounds, hydroxyapatite is more preferable. Hydroxyapatite has an excellent biocompatibility because it has the same structure as the mineral main component of bone. Moreover, when manufacturing the bone filling spacer 1 of this invention, the raw material hydroxyapatite particle | grains have more preferable what was temporarily baked at 500-1000 degreeC. Since the activity of the hydroxyapatite particles calcined at such a temperature is suppressed to some extent, uneven sintering due to rapid progress of sintering is suppressed, and a sintered body having no unevenness in strength can be obtained.
[0043]
In the present invention, the porosity of the ceramic is preferably 0 to 70%, and more preferably 30 to 50%. By setting the porosity within this range, it is possible to exhibit good biocompatibility while maintaining strength and promote osteogenesis by bone conduction.
[0044]
As a constituent material of the bone filling spacer 1 of the present invention, in addition to the ceramic material, a composite material of the ceramic material and a metal material having a low biological harm such as titanium can be used.
[0045]
Such a bone replacement spacer 1 is applied to intervertebral disk replacement. An example of intervertebral disk replacement will be described below with reference to FIGS.
[0046]
1) First, using an incision instrument such as an air drill 193 or a spinal saw (not shown), a groove (bone window) 161 is formed in the vertebral body 14 of the surgical site 15 as shown by a dotted line 16 (FIG. 3, FIG. 4).
[0047]
2) Next, an undercutting saw blade (dissecting instrument) 192 is inserted from the groove (bone window) 161 (FIG. 4), and as shown by a dotted line 17, an incision is made in the axial direction of the vertebral body 14, The body 14 is incised, and the vertebral disc unit (bone fragment) 10 is taken out from the affected part 15. The vertebral body disc unit 10 is obtained by cutting out the portion surrounded by the dotted lines 16 and 17 of the operation part 15 in FIG. 3, and a part of the vertebral body 14 above and below the intervertebral disc 18 (vertebral body piece 101). Remains (joined) (see FIG. 6). By removing the vertebral body intervertebral disc unit 10, a gap 13 is formed in the vertebral body 14 of the operation part 15.
[0048]
3) Next, as shown in FIG. 5, for example, using an air drill (cutting tool) 193 under a microscope, the posterior osteophytes and ossification lesions are shaved and the disc tissue protruding backward is removed (the affected area is treated) ).
[0049]
4) Next, the bone replacement spacer 1 is attached to the vertebral disc unit 10 using a linear body 11 such as a thread (for example, bicyclyl yarn) so as to sandwich the vertebral disc unit 10 collected in the step 2). (See FIG. 6). At this time, the linear body 11 is inserted into the groove 3, the linear body 11 is wound around the bone replacement spacer 1 and the vertebral disc unit 10, and the linear body 11 is tied up so that the bone replacement spacer 1 is connected to the vertebral body. The disc unit 10 can be securely fixed.
As a result, a transplanted bone 12 composed of the vertebral body disc unit 10 and the two bone replacement spacers 1 fixed to the vertebral body disc unit 10 so as to come into contact with the vertebral body piece 101 is obtained. Thus, when the bone replacement spacer 1 is inserted into the vertebral disc unit 10 so as to sandwich the vertebral disc unit 10 using the two bone replacement spacers 1, the uniformity of the transplanted bone 12 is improved and postoperatively. In addition, the burden on the tissue around the surgical site 15 is reduced. The thickness of the bone graft 12 may be adjusted by adjusting the thickness of the vertebral body intervertebral disc unit 10 or by selecting a bone replacement spacer 1 having an appropriate thickness. Furthermore, it may be performed by performing both simultaneously.
[0050]
5) Finally, the bone graft 12 is inserted into the gap 13 so that the vertebral body contact surface 22 of the bone replacement spacer 1 contacts the incision surface 141 of the vertebral body 14 (see FIG. 6).
At this time, since the width, length, and thickness of the bone graft 12 and the bone filling spacer 1 constituting the bone bone 12 are substantially the same as the shape of the gap 13, the graft bone 12 is inserted into the gap 13 without excess or deficiency. Is done. Therefore, when the bone filling spacer 1 of the present invention is used, the transplanted bone 12 does not protrude significantly from the gap 13 or a large gap is not formed in the gap 13.
[0051]
As described above, when the intervertebral disk replacement is performed using the bone replacement spacer 1, the intervertebral disc 18 is preserved in the transplanted bone, and thus the re-inserted transplanted bone 12 does not lose its ecological function. Then, it will be housed in the vertebral body 14.
[0052]
Moreover, the vertebral body disc unit 10 can be inserted into the gap 13 in the same direction as when it is removed from the vertebral body 14. Thereby, in the operation part 15, the contact area (the contact area of the vertebral body contact surface 22 of the bone replacement spacer 1 and the incision surface 141 of the vertebral body 14) between the transplanted bone 12 and the vertebral body 14 becomes large. Therefore, the stability of the vertebral body 14 at the surgical site 15 is increased, and even when force is applied to the vertebral body 14 from various directions, the graft bone 12 and the vertebral body 14 are not easily deformed.
[0053]
Furthermore, the anchor effect is obtained by forming the groove 3 in the bone filling spacer 1 (particularly by forming it in a lattice shape). That is, since the groove 3 is formed in the bone replacement spacer 1, the bone replacement spacer 1 becomes difficult to slip from the vertebral body 14. In addition, since the surface area (the contact area between the bone filling spacer 1 and the vertebral body 14) is widened, bone tissue invades and fuses into the groove 3 after the operation, so that the bone graft 12 is firmly fixed. For this reason, the position of the bone graft 12 is suitably prevented after the operation.
[0054]
Further, by inserting the linear body 11 into each groove 3 and fixing the bone filling spacer 1 to the vertebral disc unit 10, even if the bone filling spacer 1 is broken, the fragment is the linear body 11. Since it is securely held, the fragments are prevented from falling off the grafted bone 12. Such an effect is suitably exhibited by forming the grooves 3 in a lattice shape.
[0055]
Furthermore, if the bone replacement spacer 1 is used, a vertebral body piece removed from the surgical site can be used as a component of the transplanted bone. This eliminates the need for harvesting bone grafts from other parts of the patient.
[0056]
Since the bone replacement spacer 1 of the present invention has the effects as described above, if the intervertebral disk replacement is performed using the bone replacement spacer 1 of the present invention, the buffer action of the spine is greatly impaired. Further, complications such as spinal deformity and kyphosis deformity after surgery are preferably prevented.
[0057]
In the above description, the vertebral body intervertebral disc unit 10 is given as a representative bone fragment. However, the bone fragment used in the present invention is not limited to this, and may be composed of, for example, only a fragment of the vertebral body 14. . In addition to the above-described intervertebral disk replacement, the bone filling spacer 1 of the present invention can be applied to other surgical methods such as interbody fusion.
[0058]
As mentioned above, although this invention was demonstrated based on preferred embodiment shown to an accompanying drawing, this invention is not limited to this.
For example, the cross-sectional shape of the groove 3 may be V-shaped. Further, for example, the grooves 3 may not be formed in a lattice shape. Further, for example, the vertebral body contact surface 22 may have a convex shape instead of a flat shape. Further, for example, the grafted bone may be configured using three or more bone replacement spacers.
[0059]
Furthermore, in the embodiment described above, the groove 3 is described as the best fixing means of the bone replacement spacer 1, but the fixing means may not be a groove. For example, the vertebral body disc unit 10 or the linear body may be used. 11 may be a protrusion that engages with 11.
[0060]
【Example】
A hydroxyapatite slurry (Ca / P ratio = 1.67) was prepared from a calcium hydroxide slurry and an aqueous phosphoric acid solution by a known wet synthesis method. After drying this by a spray heat drying method, spherical powder was obtained by performing temporary baking at 700 ° C. in an atmospheric furnace.
Next, the obtained hydroxyapatite spherical powder and the polymer compound aqueous solution were mixed and stirred, and then the mixture was dried to obtain a block of hydroxyapatite.
[0061]
The shrinkage after sintering was calculated from this block body, and a molded body having a desired bone filling spacer shape was produced using a lathe.
The molded body was placed in an electric furnace and sintered at 1200 ° C. for 4 hours to produce a bone filling spacer having the shape shown in FIGS.
[0062]
The size of the bone filling spacer produced in this example was 17 × 13 × 4 mm. Moreover, the groove | channel was arrange | positioned at 3x2 grid | lattice form, as shown in FIG. The cross-sectional shape of the groove was U-shaped. The groove width was 1 mm, the groove depth in the X-axis direction was 0.7 mm, and the groove depth in the Y-axis direction was 0.4 mm. The porosity of hydroxyapatite was 40%.
[0063]
Using the bone replacement spacers obtained above, several patients with cervical disc disorders were subjected to intervertebral disk replacement using bicyclyl yarn with a wire diameter of 0.3 mm when obtaining grafted bone, as described above. did.
[0064]
As a result, in all patients, the transplanted bone could be reliably inserted into the surgical site and fixed, and the cervical spine abnormality could be suitably treated.
The postoperative course was good, and no shift in the bone graft was observed even after a long period of time. In addition, no deviation between the vertebral disc unit and the bone replacement spacer was confirmed. Further, the cervical spine was not greatly impaired in cushioning property, and the surrounding bone tissue was not damaged or destroyed, and the cervical spine was maintained in a good state. Furthermore, the transplanted bone rapidly bone-unioned with the cervical vertebra, physiological reconstruction was performed very well, and posterior deformity and the like were not confirmed.
[0065]
【The invention's effect】
As described above, according to the present invention, the transplanted bone can be reliably fixed to the surgical site. Further, if the patient is subjected to intervertebral disk replacement using the bone replacement spacer of the present invention, the function of the patient's spine is unlikely to be impaired.
[0066]
For this reason, it becomes possible to reliably treat patients with spinal diseases such as intervertebral disc disorders and ligament ossification. Further, even after the operation, the patient can maintain a good state, and complications caused by the interbody fusion are suitably suppressed.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an embodiment of a bone filling spacer of the present invention.
2 is a plan view, a front view, and a side view of the bone repair spacer shown in FIG. 1. FIG.
FIG. 3 is a diagram for explaining a method of using the bone filling spacer shown in FIG. 1;
4 is a view for explaining a method of using the bone filling spacer shown in FIG. 1; FIG.
FIG. 5 is a view for explaining how to use the bone filling spacer shown in FIG. 1;
FIG. 6 is a view for explaining a method of using the bone filling spacer shown in FIG.
FIG. 7 is a view showing a vertebral body subjected to a conventional interbody fusion.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Bone filling spacer 2 Main body 21 Bone fragment contact surface 22 Vertebral contact surface 3, 3X, 3Y Groove 31 Intersection 10 Vertebral disc unit 101 Vertebral piece 11 Linear body 12 Implanted bone 13 Cavity 14 Vertebral body 141 Incision surface 15 Surgical part 16, 17 Dotted line 161 Bone window 18 Intervertebral disc 192 Undercutting saw blade 193 Air drill 900 Vertebral bone fragment 901 Vertebral body

Claims (8)

Used to cut out a bone piece with a part of the vertebral body joined to the top and bottom of the intervertebral disc from the surgical site and insert it into the gap formed in the surgical site together with the bone piece. Bone replacement spacer,
The bone replacement spacer has a plate shape or a block shape, and a plurality of grooves into which a linear body for fixing the bone replacement spacer to the bone piece is inserted in a surface facing the surface in contact with the bone piece. The depth of the grooves along one direction of the lattice is different from the depth of the grooves along the other direction of the lattice, and rises at the portion where the linear bodies inserted into these grooves intersect. And the linear body is formed so as not to protrude from the groove, and is inserted into the gap while being inserted into the bone fragment and fixed with the linear body. A bone repair spacer, wherein the surface on which the surface is formed abuts against the cut surface of the gap and the groove exhibits an anchor effect.   The bone filling spacer according to claim 1, wherein a cross section of the groove has a U shape.   The bone replacement spacer according to claim 1 or 2, wherein the bone replacement spacer is used so as to sandwich a bone fragment with at least two bone replacement spacers.   The bone replacement spacer according to any one of claims 1 to 3, wherein a ceramic material is used as a constituent material.   The bone repair spacer according to claim 4, wherein the ceramic material is made of a calcium phosphate compound.   The bone filling spacer according to claim 5, wherein the calcium phosphate compound has a Ca / P ratio of 1.0 to 2.0.   The bone filling spacer according to claim 5 or 6, wherein the calcium phosphate compound is hydroxyapatite.   The bone filling spacer according to any one of claims 4 to 7, wherein the ceramic has a porosity of 0 to 70%.

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