A degradable inorganic hernia patch

Abstract

The present invention relates to a degradable inorganic hernia patch. A degradable inorganic hernia patch, which is a rectangular plate with a thickness of 0.1 - 0.3 mm, a width of 7 - 12 cm, and a length of 13 - 20 cm. Its material is magnesium with a purity greater than 99.9%. The hernia patch is a non-mesh sheet, with a complete sheet structure and no micropores. One side of the hernia patch is coated with a 0.5-mm-thick bioadhesive. The hernia patch made by the present invention is degradable, and its degradation rate is slower than that of traditional mesh inorganic patches. Before degradation, the structural strength it provides is also greater than that of traditional mesh inorganic patches.

Description

Technical Field

[0001] The present invention relates to a degradable inorganic hernia patch. Background Art

[0002] Currently, traditional degradable hernia patches are meshes woven from degradable organic material fibers or metal meshes woven from degradable metal fibers. In short, they are all grid-shaped with mesh holes in the middle. Taking the degradable metal mesh patch as an example, its manufacturing method is usually to weave metal wires or lay metal wires on a plane and then press them to form a grid. However, after the grid-shaped metal plate degrades (corrodes) in the human body, the warp and weft lines of the grid of the metal plate will break, resulting in insufficient strength (the peritoneum needs to have a certain tension to wrap the internal organs / resist the pressure formed by the internal organs - obviously, hernias are likely to occur during constipation or coughing because the internal organ pressure is the greatest at this time. The reason for the occurrence of hernias is that the abdominal cavity envelope of the human body is broken by the internal organ pressure - naturally, the patch also needs to resist the pressure formed by the human internal organs). Therefore, due to degradation in the human body, the strength of the grid-shaped patch made of metal structure will seriously decrease in the short term. In severe cases, it may lead to surgical failure, and the abdominal contents will protrude through the hernia defect to the scrotum or subcutaneous tissue, resulting in recurrence or serious complications.

[0003] Why does the absorbable patch with a mesh structure have a short support time and a rapid decrease in strength? Because the strength of the mesh structure mainly depends on the support of the warp and weft lines. The warp and weft lines, no matter what diameter of wire is used (currently, for some grid-shaped patches, in order to increase the strength of the warp and weft lines, the method of increasing the diameter of the warp and weft lines is adopted), generally speaking, their diameters will not be particularly large because an overly thick / large diameter will cause it to be impossible to weave into a mesh. After coming into contact with tissue fluid, the warp and weft lines with relatively small diameters (since the diameter of the patch fibers in the prior art cannot be unilaterally increased excessively, the diameter of the patch fibers in the prior art is always not large enough / relatively small) will break successively, resulting in a decrease in the strength of the grid-shaped absorbable patch and finally causing the patch to rupture, affecting the surgical effect.

[0004] Therefore, intuitively, the problem in the prior art is that due to the manufacturing process of the patch, the diameter cannot be unilaterally increased excessively (which is likely to cause it to be impossible to weave or the woven mesh to lose elasticity). However, the diameter is insufficient, and the strength cannot be guaranteed within a certain period of time. Therefore, the problems in the prior art of degradable patches can be summarized as: the diameters of the grid-shaped warp and weft lines are insufficient / large, and cannot provide sufficient strength under the condition of degradation.

[0005] Therefore, it is necessary to find a hernia patch that is degradable but has greater structural strength (degrades more slowly - based on the fact that the thickness of the patch cannot be increased, the duration for which the structural strength of the patch is maintained depends on the degradation rate of the patch material - however, it cannot completely not degrade. A material that does not degrade at all is a foreign body to the human body and poses a potential hazard if left in the human body. If it is removed through surgery, it will cause secondary harm to the human body). Summary of the Invention

[0006] In order to overcome the deficiencies of the prior art, the purpose of the present invention is to provide a hernia patch that is degradable but has greater structural strength (degrades at a slower rate).

[0007] The contradiction between the diameter (strength) and the performance of the patch has been introduced in the background art, and it has reached a dead end. In the traditional technical thinking, before finding a degradable metal with higher tensile strength, it is no longer possible to solve the problem by simply increasing the diameter. Therefore, to solve this problem, it is necessary to break out of the traditional technical thinking and find other technical solutions with unexpected technical effects.

[0008] Experimenters accidentally discovered that non-mesh, pure magnesium / zinc sheets can also degrade slowly in the human tissue fluid environment, and their degradation rate is very slow. That is to say, first of all, their strength, due to the absence of a mesh structure that reduces the strength of the sheet material, can meet the strength requirements for hernia repair surgery before degradation. Secondly, they can also achieve the final effect of natural degradation in the human body. It's just that compared with the mesh patch, the degradation rate is relatively slow. Moreover, this slow degradation rate exactly meets the strength-time requirement of the surgical patch. The term "strength-time" is created by the applicant himself to describe the strength requirement per unit time. Because the purer the magnesium / zinc sheet, the slower its degradation rate, resulting in its structure remaining relatively intact within a fixed time period (spanning the natural repair time of the entire hernia defect). Thus, ensuring that its strength remains at a relatively stable level within a fixed time period. And pure magnesium / zinc sheets, due to the processing characteristics of the metal, can also be made into the spatial structure form of a hernia patch. (How to make pure magnesium / zinc sheets into a patch can be seen in another patent simultaneously applied by the present applicant. Its processing technology belongs to the technical features required to solve another problem and lacks unity compared with this application, so it is applied in another patent.)

[0009] In order to verify the degradation characteristics of pure magnesium / zinc sheets in the human body after being made into hernia patches, that is, to verify the above theory, experimenters designed the following experiment. At a temperature of 36.5°C and a humidity maintained at 50 - 70%, the magnesium and zinc materials were placed in Hanks solution (used to simulate the human abdominal cavity environment).

[0010] From the above experimental data, the applicant found that when the purity of pure magnesium / zinc sheets is controlled between 1-6% and the thickness is controlled at 0.1mm, the entire patch is completely degraded in the human body within one year. (Because the internal organs will peristalsis, the patch will degrade faster under the force of internal organ squeezing - the experimental patch has no internal organs to squeeze it) and another phenomenon was also found at the same time. The higher the purity of the magnesium / zinc sheet, the slower its degradation rate in the human body. This reminds the applicant that when using pure magnesium / zinc sheets as patches, the thickness and purity need to be controlled so that the strength requirements can be met. In general, delaying the degradation rate, that is, maintaining a certain strength within a fixed time, as a sheet metal plate, only very simple materials science knowledge is needed to know that the tensile / compressive strength of the sheet metal is proportional to the integrity of its structure. The more complete the structure, the higher the tensile / compressive strength. In other words, maintaining a certain strength within a fixed time, the means adopted / the purpose achieved is to maintain the structural integrity of the metal sheet within a unit time - delaying corrosion / degradation is the primary condition for ensuring strength. According to experimental data, slowing down the degradation rate means improving the purity of magnesium flakes / zinc flakes. This requires improving the relative process during production, as shown in another patent simultaneously applied by the applicant.

[0011] In summary, the revelation of this experiment is that degradation is necessary in the final stage, but harmful in the initial stage. The experimental characteristics of pure magnesium / zinc flakes in the human body just meet this requirement. Therefore, we can follow this principle to further explore the best technical solutions and design more experiments to verify these technical solutions.

[0012] Considering the degradation rate suggested by the above experiments, the present invention adopts the following technical solution: a plate with a thickness of 0.1-0.3 mm and a rectangular shape, wherein the material is magnesium with a purity greater than 99.99%.

[0013] Furthermore, considering the degradation rate of zinc indicated by the above experiments, the material in the claims of the present invention can be replaced by zinc with a purity greater than 99.9%. Zinc, as a degradable metal, can be dissolved in the human body, and the dissolved zinc ions are compatible with the human body.

[0014] The above experiment proves that when magnesium and zinc materials are placed in Hanks liquid at a temperature of 36.5°C and humidity maintained at 50-70%, high-purity magnesium and zinc can prevent degradation from being too fast compared to alloys. (The higher the purity, the slower the degradation rate in the human body)

[0015] Further, the material is replaced with a Zn-xMg binary alloy, and the ratio of the two is: x = 0.5 - 5 wt.%. Magnesium-zinc is an essential nutrient element for the human body. As degradable metals, magnesium and zinc can degrade in the human body, and the degraded magnesium and zinc ions have good biocompatibility with the human body. wt.% is the weight percentage, which represents different weight ratios in the Zn and Mg alloy, ranging from 99.5% Zn and 0.5% Mg to 95% Zn and 5% Mg.

[0016] During the degradation process, the magnesium and zinc materials degrade in the form of pitting corrosion and gradually degrade in an environment containing chloride ions in the body. Many hole-like structures penetrating the upper and lower surfaces are formed on the surface of the magnesium and zinc materials. These pores provide a passage for the growth and crawling of human tissues, especially fibroblasts and capillaries. In other words, during degradation, the plate-shaped patch will form a mesh-like structure similar to that of the prior art. However, before the formation of pores, the structural strength provided by it is far greater than that of the mesh-shaped patch (the structural strength of the plate is greater than that of the mesh-shaped patch and also greater than that of the "plate-like object" with pre-formed micro-channels). In other words, in terms of strength comparison, the plate-shaped patch is equivalent to having an additional "before perforation" state compared to the mesh-shaped patch, and the strength of the patch during this "before perforation" state fully meets the surgical requirements of the patch. Therefore, the time during which the plate-shaped patch can provide qualified strength is significantly longer than that of the mesh-shaped patch.

[0017] To verify this theory, the following experiment was designed: At a temperature of 36.5°C, using a compressive testing machine to detect, after soaking in simulated body fluid for 3 months, the maximum compressive strengths of plate (sheet)-shaped magnesium patches, mesh magnesium patches, and ordinary degradable patches with the same thickness are shown in the following table:

[0018] Maximum compressive strength Plate-shaped magnesium patch 850 mmHg Mesh magnesium patch 500 mmHg Ordinary degradable patch 700 mmHg

[0019] This experiment perfectly verifies the above theory and also proves that, in terms of strength, the plate-shaped magnesium patch is indeed as predicted before the experiment, stronger than the mesh magnesium patch and the ordinary degradable patch. And because the properties of the magnesium-zinc materials are the same, it can be speculated that the plate-shaped zinc patch is also stronger than the mesh zinc patch and the ordinary degradable patch.

[0020] Further, one side of the hernia patch is coated with a bioadhesive. The bioadhesive can be a bioadhesive glue containing the ingredient of Bletilla striata. During production, Bletilla striata powder with a mass ratio of 10%-50% is put into the bioadhesive glue and mixed. After being evenly mixed, it is coated on the hernia patch and air-dried for later use. The bioadhesive itself has the functions of hemostasis, accelerating wound healing, and adhesion (bioadhesive glues in the prior art can achieve this effect, such as protein-based adhesives, the bioadhesive "Duomo Bang", and SUP glue). After adding Bletilla striata, since Bletilla striata contains mucilage (a variety of polysaccharides, starch, which can shorten the coagulation time and inhibit fibrinolysis, and can form an artificial thrombus to stop bleeding) and volatile oil, the mucilage and starch it contains strengthen the adhesive effect of the bioadhesive. The volatile oil it contains strengthens the effect of the bioadhesive in accelerating wound healing. And after the bioadhesive is mixed with the mucilage and starch of Bletilla striata: on the one hand, it adheres to the wound at the surgical (hernia) site, enabling the wound to stop bleeding faster.

[0021] To verify the above theory, the following animal experiment was designed: The magnesium patch was placed on an open fresh abdominal wound, and the oozing blood on the wound surface stopped after about 3 minutes; The bioadhesive was coated on an open fresh abdominal wound, and the oozing blood on the wound surface stopped after about 1.5 minutes; The magnesium patch was coated with the bioadhesive on its surface and then placed on an open fresh abdominal wound, and the oozing blood on the wound surface stopped after about 1 minute. See the following table:

[0022] Coagulation time Magnesium patch 3 minutes Bioadhesive 1.5 minutes Magnesium patch + bioadhesive 1 minute

[0023] On the other hand, the patch coated with the bioadhesive adheres to the wound at the surgical (hernia orifice) site, playing a pre-fixation role, which facilitates the subsequent suture of the patch and the hernia orifice by the surgeon. During traditional suture, it is necessary to first fix / press the patch on the hernia orifice and then pass a needle through the patch and the hernia orifice. Under endoscopic surgery, there is a lack of conditions to fix / press the patch on the hernia orifice. However, with the patch of bioadhesive - Bletilla striata powder, it has the technical effect of pre-fixation. When it is spread flat at the hernia orifice and gently pressed for a while, it can adhere to the hernia orifice. At this time, when suturing, there is no need to fix / press the patch on the hernia orifice separately, which brings great convenience to the endoscopic hernia repair surgery, greatly reduces the difficulty of the surgery, and greatly improves the effect of the repair surgery.

[0024] Animal experiments have shown that it takes 10 seconds to reliably fix the magnesium patch coated with the bioadhesive on a fresh abdominal wound, and no additional suture fixation is required; It takes 25 seconds to fix the non-absorbable polypropylene patch on an open fresh abdominal wound, and 6 - 8 stitches are needed; It takes about 30 seconds to fix the absorbable polyglycolic acid patch on an open fresh abdominal wound, and about 6 - 8 stitches are needed. See the following table:

[0025] Patch placement time Whether fixation is required Magnesium patch plus bioadhesive 10 seconds No Non-absorbable polypropylene patch 15 seconds Partially required Absorbable polyglycolic acid patch 20 seconds Partially required

[0026] Thirdly, since the biological glue is not easily soluble in human tissue fluid, the patch with the biological glue coated on one side blocks the degradation effect of the tissue fluid on the patch before dissolution, which is equivalent to delaying the degradation rate of the patch. Moreover, the degradation rate of the patch can be further delayed by adjusting the glue composition and the coating thickness.

[0027] Experiments have shown that the degradation time of the magnesium patch in the animal body is 6 months. After coating with the biological glue, the degradation time of the magnesium patch is extended to 8 months, and the degradation time of the absorbable polyglycolic acid patch is 3 months. See the following table:

[0028] Complete degradation time Magnesium patch 6 months Magnesium patch + bioadhesive 8 months Absorbable polyglycolic acid patch 3 months

[0029] Furthermore, as discussed above, the Bletilla striata powder contains mucilage and starch, which are the main components of traditional glue (paste). Therefore, a new technical solution is obtained: the biological glue is a heated solution of Bletilla striata powder and water at a ratio of 1:6. Considering the chemical properties of starch, the heating temperature does not exceed 80 degrees.

[0030] Furthermore, the above-mentioned patch is pre-rolled into a cylindrical shape with a diameter of and a length of, and is tied with a degradable thread around the periphery. The cylindrical shape is convenient for pre-placing at the top of the inner cavity of the endoscope. After reaching the surgical site, the cylindrical hernia patch is pushed out through the endoscope and arranged at the place where surgery is needed. Then, the degradable thread around the periphery is cut with scissors carried by the endoscope. The hernia patch made of the plate material naturally unfolds into a flat state due to its own elasticity, and then the surgeon continues to perform the hernia repair surgery on this basis.

[0031] Furthermore, the purity of the magnesium material is greater than 99.99%, and the purity of the zinc material is greater than 99.98%.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] 1. The patch provided by the present invention is biodegradable in the human body, and the substances formed after degradation are compatible with the human body and harmless to the human body (reference can be made to the degradation research of magnesium-zinc in the human body).

[0034] 2. The patch provided by the present invention provides a patch with greater structural strength through the integrity of the structure. Through the degradability of the materials used, micropores penetrating the patch are formed, providing the same pore channels for tissue growth as traditional patches.

[0035] 3. By coating the biological glue on one side of the patch:

[0036] A. It helps the wound stop bleeding quickly;

[0037] B. It delays the degradation rate of the patch,

[0038] C. The patch has the effect of pre - fixation (at the hernia orifice), providing great convenience for endoscopic surgery.

[0039] 4. Adding the Bletilla striata component to the bio - glue increases the above - mentioned effects of the bio - glue. Bletilla striata contains mucilage (various polysaccharides, starch). On the one hand, it has the function of traditional Chinese medicine to help stop bleeding quickly, and on the other hand, it has the function of glue.

[0040] 5. Using magnesium / zinc with a purity greater than 99.99% further delays the degradation rate of the metal. Specific embodiments

[0041] This experiment compared a commercially available non - absorbable organic patch, an absorbable organic patch, an absorbable mesh patch, and the plate - shaped magnesium patch of this application in terms of the key index: time - strength in simulated human tissue fluid (Hanks solution).

[0042]

[0043] From the table, it can be found that the plate - shaped magnesium patch still has a compressive strength of 850 mmHg after 6 months.

[0044] The mesh - shaped magnesium patch has a compressive strength of 500 mmHg after 5 months. In terms of both the degradation time and the strength provided, it is less than that of the plate - shaped magnesium patch.

[0045] Absorbable polyglycolic acid has a compressive strength of 700 mmHg after 3 months and after 5 months. Its degradation time is shorter than that of the plate - shaped magnesium patch. That is to say, after 3 months, due to the corrosion of the patch structure, it can no longer provide structural support with a certain strength (less than 700 mmHg).

[0046] The non - absorbable polypropylene patch will not be discussed here. It remains in the patient's body as a foreign body for life, forming a potential hazard.

Claims

1. A degradable inorganic hernia patch, characterized in that: A rectangular thin sheet with a thickness of 0.1 - 0.3 mm, a width of 7 - 12 cm, and a length of 13 - 20 cm, made of magnesium with a purity greater than 99.9%. The hernia patch is a non-mesh sheet material with a complete sheet structure and no micropores. One side of the hernia patch is coated with a 0.5-mm-thick bioadhesive.

2. The biodegradable inorganic hernia patch according to claim 1, characterized in that: The material is replaced with zinc with a purity greater than 99.9%.

3. The hernia patch according to claim 1 or 2, characterized in that: The purity of the magnesium or zinc is greater than 99.99%.

4. The hernia patch according to claim 1, wherein: The bioadhesive contains 10 - 50% by mass of bletilla striata powder.

5. The hernia patch according to claim 1 or 4, characterized in that: The bioadhesive is made by mixing an aqueous solution of bletilla striata powder and water at a ratio of 1:6 and heating it to no higher than 80°C.

6. The hernia patch according to claim 1, wherein: The thickness is 0.2 mm and the size is 10×15 cm.

7. The biodegradable inorganic hernia patch according to claim 1, characterized in that: The patch described in claim 1 is rolled into a cylindrical roll with an outer diameter of 4 mm and a height of 15 cm, and the outer circle is tied with a silk thread.

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