JPH0518576B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Application Field> The present invention relates to a suture needle used for medical purposes. <Prior art> Conventional methods for finishing the surface of medical suture needles include buffing, electrolytic polishing, and chemical polishing, among which buffing is particularly popular. It was often implemented. <Problems to be Solved by the Invention> However, the reason why this buffing finishing method is often practiced is that because this method is a mechanical processing, there is no need to worry about wastewater treatment, and the surface is relatively smooth and the polishing direction can be easily adjusted. By performing this process in the axial direction of the needle, it is possible to obtain a surface of the needle that is mirror-like to the naked eye and has uniform, extremely fine vertical stripes as shown in Figure 3 even when magnified 3000 times. It was hot. On the other hand, the electrolytic polishing method is also sometimes carried out, but in this method, electricity is forced to flow through the needle to cause electrolysis and dissolve the surface, so it looks like a smooth mirror surface to the naked eye. Although the unevenness is very small, if you look at the surface of the needle under 3000x magnification, you will see a shallow crater-like surface created by the gas generated during electrolysis adhering to the surface, as shown in Figure 4. It had the disadvantage of having Furthermore, unlike the electropolishing method, the chemical polishing method is a method in which the surface of the needle is naturally dissolved by the acid without forcing a current to flow (of course, even in this case, in extreme places electrolytic action is occurring),
Depending on the crystal orientation of each crystal grain of the material, some crystal grains are easily polished and others are not, and this causes unevenness to be formed on the surface of the needle. Recently, suture needles used in surgery are often made of austenitic stainless steel, but in this case, they are work-hardened by wire drawing and used as is without softening. (However, in order to soften only the hole, the general structure may be used.) In this case, the crystal has a general structure shown in Fig. 5, but one crystal grain in particular is made to stand out in Fig. 6. As shown, it has a so-called wire-drawn structure with elongated crystals. Therefore,
When austenitic stainless steel in such a state is selectively melted using a chemical polishing finishing method, it appears smooth and mirror-like to the naked eye, but when magnified 3000 times, it appears as shown in Figure 7. As shown in the figure, it can be seen that the unevenness is formed in a long striped manner. This seventh
The width of the convex shape shown in the figure is 1 to 6 mm on the drawing, so
In reality, the protrusions are approximately 0.3 to 2μ in size, and are 10 to 100 times larger than the unevenness formed on needles manufactured by the buffing method described above.The unevenness formed on the entire surface is rough, and the piercing performance is There was a problem with that. Furthermore, as shown in US Pat. No. 4,072,041,
A method of applying silicone coating to a suture needle is also known, but when silicone is coated on a suture needle manufactured by a general manufacturing method, the effect of the silicone decreases drastically after several uses, so the effect is not as noticeable. I had a problem that didn't exist. The suturing needle according to the present invention is a completely new technology developed in view of these conventional drawbacks and problems, and in particular, by applying an anti-friction agent to the needle manufactured by a specific polishing method. The present invention aims to provide a completely new suture needle that can significantly improve piercing performance by utilizing the lubricating action of an anti-friction agent. <Means for Solving the Problems> The present invention provides at least one needle having at least a needle tip and a body portion thereof, which have concave grooves in the direction of the wire drawing structure formed by chemically polishing the surface of steel that maintains the wire drawing structure as it is. This medical suture needle is characterized by having its tip portion coated with silicone. <Function> As described above, in the suture needle according to the present invention, at least the tip of the needle is coated with silicone, which is obtained by chemically polishing the surface of the steel with the drawn wire structure, so that the drawn wire structure is coated with silicone. The silicone is reliably filled into the deep longitudinal grooves in the direction of the line tissue and is firmly held in place, so when the needle is inserted, a small portion of this silicone gradually becomes longer and acts as a lubricant. This makes it possible to significantly enhance the silicone effect and significantly improve the piercing performance of suture needles. <Example> As mentioned above, in the prior art, a suture needle whose surface was polished to a mirror finish by methods such as buffing, electrolytic polishing, and chemical polishing was used as is. When using the manufactured needles, there was considerable penetration resistance, and as mentioned above, suture needles manufactured using the buffing finishing method, which was considered to have the best penetration performance, were also fully satisfactory. It wasn't something that should have been done. Therefore, in order to investigate the piercing performance of needles manufactured by conventional methods, the present inventor calculated the piercing resistance (g) of round needles with a needle diameter of 0.8 mm manufactured by each method. The results shown in Table 1 below were obtained by investigating the maximum resistance until the tip of the wire passed through 20 mm.

[Table] The above values are the average values obtained by piercing 10 times with 10 needles of each type. In addition, the needle has the above-mentioned surface finish that maintains the wire drawing structure as it is. The present inventor has conducted various research and development over many years to determine whether or not it is possible to further improve the piercing performance of the suture needle manufactured by the method described above by subjecting the suture needle to some kind of processing. As a result of our research, we have found that when an anti-friction agent is applied to the surface of a needle manufactured using a specific polishing method with concave grooves in the direction of the wire drawing structure, the surface frictional resistance of the needle is reduced. The present inventors have discovered that the needle penetration performance can be significantly improved by reducing the amount of water over a long period of time. However, since suture needles pass through body tissue, only antifriction agents that do not have a negative effect on the body can be used. The anti-friction agent will only reliably adhere to needles that have been polished, and therefore, as will be explained in detail later, applying an anti-friction agent will only have an effect on needles that have been polished using a special method. It has become clear that this cannot be done. First, when carrying out the present invention, we considered what could be used as an anti-friction agent, and it became clear that since the suture needle passes through body tissue, the anti-friction agent that could be used was limited to silicone. It became. It has also been found that among the silicones currently on the market, only NDX4-4159 from Dow Corning is the one whose biosafety has been officially recognized through experiments. Next, we applied silicone to needles that had been polished using the various methods described above and conducted a penetration test, and found that the needles that had been chemically polished and coated with silicone had extremely good penetration performance. However, it was found that this good performance was maintained for a long time. FIG. 1 shows a suture needle according to the present invention, in which the needle tip part 8 and body part 7 are drawn wire tissue, and the hole part 6
Only one organization is a general organization. Silicone 2 is coated only on the surface of the needle tip 8 of the needle 1 manufactured by a chemical polishing method. FIG. 2 is an enlarged cross-sectional view of a part of the needle 1, in which silicone 2 is filled in grooves 4 formed between protrusions 3 provided around the needle 1. In the figure, 5 is a suture thread attached to the hole 6 of the needle 1. When the surface of austenitic stainless steel is subjected to chemical polishing while the structure is still wire-drawn, rough irregularities are formed in the form of streaks as shown in FIG. 7, as already explained. However, as is clear from comparing Figures 6 and 7, the grooves in Figure 7 are not necessarily formed in the same way as the crystal grains in Figure 6, and chemical polishing is caused by potential differences in extreme locations. and progress,
Since the grooves progress around minute inclusions, it is rare that the entire length of the crystal grain becomes a groove, and the groove is often formed to be shorter and wider than the crystal grain. In any case, when this is coated with silicone, the silicone 2 is reliably filled and fixed in the concave grooves 4 formed in the form of stripes as described above, and the needle 1 is inserted into the tissue of the body. When the needle 1 is passed through, only the convex portion 3 comes into contact with the tissue, and at that time, a small portion of the surface of the silicone 2 fixed in the concave groove 4 acts as a lubricant to prevent the needle 1 from penetrating. Smooth the needle 1
It has been discovered that the piercing performance of Also, the silicone 2 used for one piercing of the needle 1
is extremely small, so it was found that even if Needle 1 was used several dozen times, its performance would hardly deteriorate. Next, research will be conducted to find out why the penetration performance cannot be significantly improved when silicone is applied to needles other than needles that have been chemically polished on the surface of drawn steel. Where I did it,
A needle whose surface has been electrolytically polished does not have rough and deep vertical grooves consisting of protrusions 3 and concave grooves 4 as in the case of chemical polishing, and the surface of a needle whose surface has been buffed may not be too fine. Since a concavo-convex strip with a sharp tip is formed, there is no room for silicone to be inserted into the concave strip and securely adhered to the needle. It was found that even if it was applied, the effect was not that great. In particular, it has become clear that the silicone effect of these products is drastically reduced after several uses. When applying the silicone 2 to the needle 1 in carrying out the present invention, methods such as dipping the silicone in a solution in which the silicone is dissolved in a solvent or applying the silicone solution with a brush may be considered. The needle was immersed in a 3% solvent solution of Dow Corning NDX4-4159 silicone and dried. A round needle with a needle diameter of 0.8 mm was coated with silicone and the maximum resistance (g) until it passed through a 20 mm tip was investigated, and the results shown in Table 2 below were obtained.

[Table] The above values are the average values obtained by piercing 10 times with 10 needles of each type. In addition, the needle has the above-mentioned surface finish that maintains the wire drawing structure as it is. Therefore, in order to carry out the present invention, the crystal grains of the material of the needle must remain in the elongated wire drawing structure, and by chemically polishing the needle material that satisfies this condition, the surface of the needle must have a certain degree of axial direction. It is clear that major requirements are that the needle be formed with elongated grooves having a certain dimension and that at least the tip of the needle be coated with silicone. <Effects of the Invention> Since the suturing needle according to the present invention has the structure and function as described above, when the needle of the present invention is used, there is little resistance to piercing the body tissue, and the needle can be penetrated extremely smoothly. Furthermore, the needle according to the present invention has the characteristics that there is no risk of damaging the tissue or having any adverse effects, and furthermore, the needle according to the present invention can be mass-produced at low cost.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of the needle according to the present invention, Fig. 2 is an enlarged cross-sectional view thereof, Figs. 3 and 7 are 3000 times enlarged views of the surface of the needle, and Figs. 4 to 6 are respectively FIG. 3 is an enlarged explanatory view of a mirror surface of a needle polished by various methods. 1 is a needle, 2 is silicone, 3 is a convex part, 4 is a groove, 5 is a thread, 6 is a hole part, 7 is a body part, and 8 is a needle tip part.

Claims (1)

[Claims] 1. The surface of the steel that maintains the wire drawing structure is chemically polished to form concave grooves in the direction of the wire drawing structure on at least the needle tip and the body. At least the tip of the needle is coated with silicone. A medical suture needle characterized by: