JPH0329414B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the treatment of bone voids, such as tooth extractions, or severe defects in the skeletal structure supporting the contents of the eye socket, i.e., new bone created by treatment, surgery, accidents, etc. The present invention relates to a structure for treating voids. Providing a portion of tissue to fill or cover the voids in the bone to attract blood in liquid suspension by capillary action until a coagulum is formed leading to the formation of tissue and bone. is one of the objects of the present invention. This tissue section is a porous network with interconnected spaces, or spaces between connected strand fibers, which fill with blood by capillary action, forming strands of coagulated blood. . This tissue part is made of substances that are biodegradable, such as polylactic acid. When this tissue area fills with blood, the blood clots, but this clot is similar to normal blood in that it is held as a reticulated blood clot within a space spanning the tissue area, rather than as a solid mass of coagulated blood. It is different from coagulation. The clotted blood strands undergo a normal maturation process. By the time the mesh blood clot has fully matured into healed tissue and bone, the mesh has been completely degraded in vivo. Additionally, if there is a tissue portion in the void, the amount of coagulated blood will be less than without the method.

In some cases, patients may experience distress due to incomplete clotting, and one purpose of the present invention is to impregnate the mesh tissue area with a hemostatic agent such as thrombin or thromboplastin. Using an impregnated tissue section in this way aids coagulation in two ways. (1) They reduce the amount of blood needed to close the surgical cavity and act as a mechanical template for the clotting process; (2) The hemostatic agent chemically interacts with the patient's own functional coagulation factors and Decrease the aggregation factor deficiency of.

The present invention will be more clearly understood from the detailed description of preferred embodiments of the inventive idea in conjunction with the accompanying drawings. Throughout the text, numbers refer to the same parts as those in the drawings.

FIG. 1 is a three-dimensional view of a tissue section completing a bone void embodying the present invention.

FIG. 2 is a cross-sectional view taken along line 2--2 in FIG.

Figure 2a is another example of a tissue section completing a bone void.

Figure 2b is a cross-sectional view taken along line 2b-2b in Figure 2a.

FIG. 3 is a cross-sectional view of FIG. 1 illustrating a finished tooth cavity created by tooth extraction, two-thirds of which is filled with blood.

Figure 4 is the same cross-sectional view as Figure 3, but the finished area is completely filled with blood.

FIG. 5 is the same cross-sectional view as FIG. 4, but after four months have passed, and instead of the clumped blood shown in FIGS. 3 and 4, a firm tissue has formed. The tissue thickness of all finished areas is reduced by 75% due to metabolism (degradation in the body).

FIG. 6 is the same cross-sectional view as FIG. 5, but substantially 6
Several months have passed since then, and the tissue area has healed, leaving only scattered areas of finished tissue.

FIG. 7 is the same cross-sectional view as FIG. 6, but the finished tissue has been completely metabolized and the voids have healed.

FIG. 8 is a three-dimensional view of an ocular foramen implant prepared according to the present invention.

FIG. 9 is the same three-dimensional view as FIG. 8, but viewed from the opposite side.

FIG. 10 is a cross-sectional view taken along line 10-10 of FIG.

FIG. 11 is a three-dimensional view of another specific example of the transplanted tissues shown in FIGS. 8, 9, and 10.

FIG. 11a is an inverted stereoscopic view of the implanted tissue of FIG. 11.

FIG. 12 is a cross-sectional view taken along line 12-12 in FIG.

FIG. 13 is a three-dimensional view of a human skull in the area of the eyeball hole, and the indentation shows the state in which the eyehole graft tissue is fitted over the gap at the bottom of the eyehole, and the gap is indicated by a dotted line.

FIG. 14 is a representative enlarged cross-sectional view of a portion of the bony void-finished tissue portion of FIGS. 1-13.

Regarding the details in the figure, the finishing material for the bone void is A.
(particularly those shown in Figures 1 and 2) in the form of a plug-like network. The porous mesh plug is
It is formed by polylactic acid with the above-mentioned voids having an interconnected cell-like morphology. High molecular weight polylactic acid polymers are converted into networks by methods well known in the plastics industry.

Generally speaking, the maxilla receives a blood supply, so that, for example, a tooth gap created by a tooth extraction can be sufficiently healed by blood. A blood supply is required for blood clots to be converted into tissue and bone. It is generally accepted that the blood supply to the lower jaw is not as great as that to the upper jaw, and the blood supply is often insufficient to nourish the newly formed blood clots in the newly formed bone spaces. be. About a person who had a tooth extracted in the third molar area of the lower jaw
In 20% of cases, the blood supply is insufficient, resulting in what is known as a "dry socket", which causes problems with brittleness and pain at the socket before it fully heals, allowing tissue and bone formation to heal. It has been found that the time is extended. The present invention eliminates this "dry socket" complication.

With further reference to the accompanying figures, the polylactic acid of FIG. 1 is in the embodiment formed as a porous mesh plug A suitable for insertion into a bone cavity 10 created by tooth extraction. The porous mesh plug A contains a number of interconnected fissures 12. For example, after a bone cavity has been created by tooth extraction, a plug is placed in the cavity and the plug draws liquid blood by capillary action through the interconnected fissures in the material. It functions to attract. When the mesh of the plug fills with blood, it completely occupies the bone void and puts pressure on the active source of blood flow. The source of the outflow is the artery reaching the void through the bone, and this pressure helps to stop the bleeding, while at the same time the network of blood-filled plugs is necessarily mechanically attached to a continuous source of blood. do it like this. This continuous source of blood is the fissure shown as 14 next to the cavity 10 shown in FIG.

As soon as plug A is filled with fresh blood, the blood within the mesh of the plug begins the clotting process and forms a normal blood clot. However, intramesh blood clots differ from normal blood clots in that they are held stagnant within the mesh in the form of strands of blood in many separate clumps throughout the plug. These strands are formed by blood moving from the arteries on the sides of the bony cavity into the channels or crevices of the plug's network. This mesh is capable of holding a multi-stranded mass of blood clot stagnant within the framework of the mesh plug. See Figure 3.

The individual independent strands of the blood clot begin to mature just as other blood clots do. As the blood cell strand matures, the strand metabolizes the supporting network. The individual strands of the mature blood clot increase strength and capacity while digesting the supporting polylactic acid network. The result of this process is that by the time the blood clot has matured into healed tissue and/or bone, the network has been completely metabolized by the cells of the network blood clot, granular tissue, and fibrous tissue. That's true.
When the wound has healed, the network is no longer present.

In this case, if a plug A having a mesh structure is used, which will be mentioned later, the number of blood clots that require nutrients will be reduced.
Blood nutrients are provided by veins on the sides of the bone cavity, and mesh plugs attract liquid blood from the veins. As mentioned above, although the blood supply to the mandible is low, when the demand is reduced by the plug, the chances of healing are improved without any hindrance. Furthermore
PLA (polylactic acid) network clots have a limited surface area from a limited number of venous sources because the network structure holds small volumes of blood clots stagnant in the form of multiple clot strands. Eliminates the logistical problems associated with supplying blood to a single large volume mass.

The interrelated strands facilitate the formation of new capillaries from the venous source directly toward the center of the clot network, thereby creating a homogeneous blood clot of relatively large volume when no network stopper is used. It would allow the entire volume of the network mass to be more uniformly supplied with blood, rather than relying on the slow formation of new capillaries from a limited surface area.

Bone voids are created under a variety of different developmental and pathological conditions. Bone voids can occur anywhere in the skeletal structure, but most frequently occur in the upper and lower jaws. Therefore, this discussion uses both the polylactic acid materials of Figures 1 and 2a (the material in Figure 1 is an open cellular network structure, and the material in Figure 2a is a spun fiber) to examine the upper and lower jaws. It will be directed to promoting intact healing of the bone voids.

Whenever a tooth is extracted, a bone gap is created in the upper and lower jaws. Whenever a pathological lesion such as a pustule or central bone tumor is removed, a large bone void is created. PLA network finishes, as previously discussed, can be advantageously used to promote rapid and trouble-free healing of these large bone voids and voids created by tooth extractions.

Extractions of teeth in the posterior part of the upper jaw sometimes cause special suffering when the infection is directly transmitted to the maxillary vein. This condition can also lead to oral/cavity fistula formation, which often requires an extra surgical procedure to close it. PLA mesh structures have the advantage that they can also be used in such cases to allow tooth extraction wounds to heal quickly and without problems, thereby preventing oral cavity/air conditioning infections.

A common problem that arises from severe maxillary surface trauma is a significant loss of integrity of the skeletal structure supporting the contents of the ocular foramen (the ocular foraminal floor). Loss of significant area of the ocular foraminal floor causes herniation of the ocular foraminal contents (fat and muscle) into the maxilla, which is located directly below the ocular foraminal floor. Such herniation of the ocular foramen contents often results in a reduction in the level of the stomatal membrane in the affected eye, and extraocular musculature may become entrained between the fractured bone fragments. As a result of both of these, if left uncorrected,
Severe double vision occurs due to ocular deterioration and loss of extraocular muscle function.

A variety of materials in the form of flattened tissue sections are currently used as ocular hole floor prostheses to separate the healing bone fragments and artificially hold the ocular hole contents in their normal position. Two of the most common of these tissue sections are made from Teflon (TM) and Supramid (TM) materials. These two substances are prepared from active substances and are formed into a very thin membrane that can be surgically inserted through an opening or crevice in the ocular foramen floor between the intact ocular foramen floor bone and the ocular soft tissue contents. inserted into. Tissue segments made from these materials have been used successfully to treat severe ocular foramen floor fissures, but they also have the significant drawback of remaining intact and permanently in the place where they are inserted. ing. Therefore, from time to time, this tissue segment moves from its original location, creating visual irritation and impairing eye movement, and sometimes causing osteolysis through the incision used to insert this tissue segment. The polylactic acid network membrane described herein is made thin enough to be accepted as part of the ocular foraminal floor implant, providing the same stability to the ocular omental contents as is, but also supporting it. The clotted blood is gradually metabolized as it is converted into bone and healed tissue. The most desirable advantage of the network material as an ocular aperture bed implant is that it provides an underlay or support for the ocular aperture contents and is absent after the ocular aperture floor has healed.

Referring to FIG. 13, the cavity 18 in the ocular hole floor 20 is shown. Laid on the bed is the implant 22 of Figures 8, 9 and 10, which is made of polylactic acid and has a top layer or first solid smooth layer of polylactic acid about 0.1 mm thick. continuous surface 2
4 and a complete second or lower layer 26 of cellular polylactic acid in the form of a cellular network approximately 0.2 mm thick. The implant 22 is positioned as shown in FIG. 13 with the solid surface 24 on top. The smooth solid surface 24 of the upper layer allows normal movement of the ocular cavity contents. Cellular network surface 26 undergoes degradation in vivo at a faster rate than surface 24 due to its larger exposed surface area, thereby causing surface 2
4 to stay in place longer and support the ocular cavity contents. Graft tissue 22 is metabolized in the same manner as the tissue portion of the bone void of FIGS. 1-7, as previously described. Another ocular hole implant 28 is shown in FIGS. 11 and 12, which includes an upper smooth continuous layer 30 of polylactic acid approximately 0.1 mm thick in the form of a spun glass, and a top smooth continuous layer 30 also made of polylactic acid. Thickness approx. 0.3
mm spun glass shape complete second or bottom layer 3
It consists of 2.

A person suffering from one of the blood clotting defects (hemophilia or Von Willenbrand disease) may happen to have to undergo a tooth extraction or other minor oral surgical procedure. As described herein, the polylactic acid network described above can function as a more effective therapeutic agent than currently available hemostatic agents.

Polylactic acid networks, either in the form of open interconnected cells or in the form of "spun glass", will be prepared by standard methods. However, in the case of open cell types, just before the pneumatophores are activated,
When dissolving the PLA polymer (or just before ejecting the dissolved PLA polymer from the nozzle if spun into glass form), a hemostatic agent such as thrombin or thromboplastin is mixed into the liquid. When the vesicle-forming agent is activated (or when the resulting solution is squirted through a nozzle in the case of "spun crow" formation), the final product emerges with the hemostatic agent incorporated into and on its surface. .

PLA constructs impregnated with hemostatic agents assist the blood clotting mechanism in two ways. (1) The PLA construct acts as a mechanical template for the coagulation process and to reduce the amount of blood needed to fill the surgical void. (2) The patient's own functional clotting factors and the hemostatic agent (thrombin or thromboplastin) chemically interact to reduce the effects of the patient's clotting factor deficiency.

[Brief explanation of the drawing]

FIG. 1 is a three-dimensional view of a tissue section completing a bone void embodying the present invention. FIG. 2 is a cross-sectional view taken along line 2--2 in FIG. Figure 2a is another example of a tissue section completing a bone void. Figure 2b is a cross-sectional view taken along line 2b-2b of Figure 2a. FIG. 3 is a cross-sectional view of FIG. 1 in which the tooth gap created by tooth extraction is finished as an example, and its 2/2
3 is filled with blood. Figure 4 is the same cross-sectional view as Figure 3, but the finished area is completely filled with blood. Figure 5 is the same cross-sectional view as Figure 4, but after four months have passed, and instead of the clumped blood shown in Figures 3 and 4, there is firm tissue. is formed, and the tissue thickness of all finished parts is reduced by 75% due to metabolism (decomposition in the body).
is also decreasing. FIG. 6 is the same cross-sectional view as FIG. 5, but it has been substantially 6 months since the tissue area has healed and only scattered areas of finished tissue remain. FIG. 7 is the same cross-sectional view as FIG. 6, but the finished tissue has been completely metabolized and the voids have healed. FIG. 8 is a three-dimensional view of an ocular foramen implant prepared according to the present invention. Figure 9 is the same three-dimensional view as Figure 8, but viewed from the opposite side. FIG. 10 is a cross-sectional view taken along line 10--10 of FIG. FIG. 11 is a three-dimensional view of another specific example of the transplanted tissue shown in FIGS. 8, 9, and 10. FIG. 11a is a three-dimensional view of the transplanted tissue of FIG. 11 turned over. FIG. 12 is a cross-sectional view taken along line 12--12 of FIG. 11. Figure 13 is a three-dimensional view of a human skull in the area of the eyeball hole, and the indentation shows the state in which the eyehole transplant tissue is placed over the gap at the bottom of the eyehole, and the gap is indicated by a dotted line. . FIG. 14 is a representative enlarged cross-sectional view of a portion of the bony void-finished tissue portion of FIGS. 1-10 and FIG. 13; The symbols in the drawings have the following meanings. A...Porous mesh plug, 10...Bone void formed by tooth extraction, 12...Cleft, 14...Cleft, 16...Capillary, 18...Void, 20...Ocular foramen floor, 22... implanted tissue, 24...solid surface,
26... Network structure surface of cellular polylactic acid, 28...
... Ocular hole graft tissue, 30 ... Continuous layer, 32 ... Lower layer.

Claims (1)

[Scope of Claims] 1 (a) consisting of a body formed of polylactic acid; (b) said body having a shape sufficient to fill the voids of the bone and having a mesh structure; (c) the body has enclosed therein interconnected randomly located spaces of random size and shape, each space connecting with the other spaces;
It communicates with the outside of the body part, through which blood is drawn by capillary action and fills the body part with blood, so that the bony void filled and covered by the body part is filled with blood. A structure that processes and heals bone cavities as it is broken down in the body. 2 (a) comprising a body formed of polylactic acid; (b) said body having a shape sufficient to fill a bone cavity and having a first portion and a second portion; and the first
The portion is a solid structure overlying one side of the second portion, the second portion having an interconnected randomly located randomly sized and shaped space enclosed therein. It has a network structure, and each space is connected to other spaces and communicates with the outside of the body, through which blood is attracted by capillary action and fills the body with blood. Thus, the bone void filled and covered by the body portion is a bone void that is healed as the second portion first decomposes in vivo and then as the first portion decomposes in vivo. A structure that processes and heals.