JPH021508B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ceramic member for filling and prosthetizing bone defects in the medical fields such as orthopedics and oral surgery.

By filling bone defects in a living body, such as the resection site of a bone tumor, or the site where bone damage has been removed due to a traffic accident or industrial accident, it promotes the growth of new bone and promotes early bone repair. In order to achieve this, the filled material must have a shape that does not move and forms many voids that allow bone growth and invasion, has good compatibility with living tissue, and has high mechanical strength. It is desirable that the material has physical properties.

By the way, conventionally, bone grafting from the patient's own ilium or fibula, which is autologous bone, is generally performed in the bone defect area where the bone has been removed as described above, from a site in the body where there is relatively sufficient bone volume. In some cases, dried calf bones have been used as a substitute. However, although the former method is most suitable for promoting the growth of new bone, there are significant limitations in harvesting the amount of bone necessary for filling, and the latter method is difficult to implant into a living body. It is rarely used at present because it can cause problems such as immune reactions that occur after admission.

In addition, as a member to replace the bone used for the filling,
Ceramic beads have been proposed, and although they are not harmful to living organisms and have extremely good affinity with tissues, they are spherical, elliptical, or other shapes that do not have sharp edges. Even after filling the bone defect, the individual beads will easily move if even the slightest external force is applied.

For this reason, there was a risk that the growth of new bone would be inhibited or, in some cases, that the new bone would escape from the filled bone defect site.

In addition, depending on the filling conditions, it is easy to become over-filled, and there are cases where the gap in which bone can grow is extremely small, so it is not harmful to living organisms and has good compatibility. However, it has not yet come to widespread use in the field of orthopedics as a prosthetic member for filling bone defects.

The present invention is a ceramic member for bone prosthesis developed in view of the above circumstances, and examples thereof will be described in detail below with reference to the drawings.

1 to 3, reference numerals 1, 2, and 3 respectively indicate ceramic members for bone prosthesis according to the present invention.
It has cylindrical protrusions 12 integrally formed with the spherical body 11, and the protrusions 12 are located at approximately equal intervals on the spherical body 11, and the tips 12a thereof are not sharp but have a rounded shape. be. One method of manufacturing such a ceramic member 1 is to pour a slurry made by mixing ceramic powder raw materials with water and an organic binder into a predetermined plaster mold, dehydrate it, take it out, dry it, and fire it.

Furthermore, in the ceramic member 2 shown in FIG.
and two cylindrical portions 22 are integrally formed as a main body, and among these, the prismatic protrusion 21 and the cylindrical portion 22 both have their tip portions 21a, 22.
It has no sharp parts, and the entire outer periphery is rounded. One method for manufacturing such a ceramic member 2 is to fill a predetermined mold with ceramic raw material powder, press mold it, and then fire it.

Furthermore, the main body forming the ceramic member 3 shown in FIG. The outer peripheral surface of the portion 31 is all rounded. One method for manufacturing such a ceramic member 3 is to wet-knead ceramic raw material powder with water and an organic binder, extrude it using a predetermined mold, cut it into a desired length, and then It is made by firing.

The required number of such ceramic members 1 (2, 3) is filled according to the size of the bone defect, but when a large number of ceramic members 1 (2, 3) are filled into the bone defect, the protrusions 12 (21, 22) of the ceramic members 1 (2, 3) are , 31) intersect with each other to form a strong structure, and as a result, the movement of the individual ceramic members 1 (2, 3) is suppressed, and the protrusions 12 (21, 3) are intersected with each other to form a strong structure.
22, 31), bone growth is allowed to grow into the three-dimensional space formed by the intersection of 22, 31), and bone repair is promoted. Therefore, the protrusion 12 (21, 22,
31) The length is determined practically based on the correlation with mechanical strength, the thickness of bones in each part of the human body, the size of bone defects, etc.
The diameter (thickness) or thickness is preferably about 0.5 to 3 mm, preferably about 1 to 2 mm, and the total length is 15 mm or less, preferably about 5 to 10 mm. In this case, the number of protrusions is 1 or more, preferably 3 to 3.
It has been confirmed through many animal experiments that about 8 units are effective.

Incidentally, as the ceramic that constitutes the main body of the ceramic members 1, 2, and 3, alumina or a calcium phosphate material such as hydroxyapatite is suitable. In other words, both of these ceramics have in common that they are not harmful to living organisms and have excellent affinity with living tissues, but the former is completely inert to living organisms;
It has particularly high mechanical strength. In addition, the latter calcium phosphate ceramics have bioactivity,
Depending on the conditions and promotion of bonding with bones, they have the property of being absorbed by the living body and replacing the bones, so it is best to use both depending on the case.

In addition, it is preferable that the outer periphery of these ceramic members has no sharp parts and is rounded throughout in order not to cause irritation to the natural bone and to avoid stress concentration. .

As described above, the ceramic member for filling a bone defect having one or more protrusions according to the present invention can be used to fill the void of the defect when the void where the bone has been excised is relatively small. is large, and even when used in conjunction with natural bone, the amount of natural bone filling, that is, the amount of bone harvested, can be significantly reduced.Moreover, the protrusions provided on the ceramic member are intertwined with each other to form a strong structure. Since the movement of individual members is suppressed in the living body, it has excellent fixation properties, and the growth and invasion of new bone into the arbitrarily shaped three-dimensional void formed by the intersection of the protrusions is promoted, and the infiltration of new bone into the affected area is improved. Its contribution to the medical field and, ultimately, to human welfare is extremely large, as it has achieved early recovery of bone morphology and function.

[Brief explanation of drawings]

1 to 3 are perspective views each showing an embodiment of a ceramic member for bone prosthesis according to the present invention. 1, 2, 3: Ceramic member, 12, 21, 2
2, 31: Projection.

Claims (1)

[Claims] 1 A member that is filled with a plurality of pieces according to the size of the bone defect space, and that forms a three-dimensional gap that allows bone growth and invasion with the protrusions of each piece intersecting, and is made of ceramics such as alumina or calcium phosphate. 1. A ceramic member for bone prosthesis, characterized in that a plurality of protrusions are integrally provided on the surface of a main body made of a ceramic member.