JPS6395041A - Medical pledget - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to the provision of a pledget that is applied for the purpose of preventing tearing of body tissue during surgical operations such as suturing and anastomosis.

(Prior art) In recent years, for example, due to advances in tracheal and bronchial surgery, surgeries related to the respiratory system have become more active. However, when performing extensive tracheal resections, the tension applied to the anastomosis is especially strong, and This concentration causes the tissue in question to be torn by the suture, causing serious complications such as suturing failure, granulation formation, and tracheal aneurysm.

Further, in other surgical operations, problems similar to those described above have occurred when the tissue is weak or sutured under tension.

Conventionally, as a means to solve this problem, a pledget made of a material harmless to the human body, such as Teflon, has been used as a patch, and sutures, anastomoses, etc. have been performed from above the pledget cloth applied to the relevant part.

However, such conventional products often cause granulation formation when suturing delicate areas such as the trachea, and especially when used on membranous areas, they often fall out into the lumen due to inflammation, causing granulation to occur in the surrounding area. It is known to cause death by suffocation.

Furthermore, since such materials are not absorbable in the body, they remain in the body indefinitely even if their function is no longer needed, and they continue to cause considerable tissue reactions.

(Problems to be Solved by the Invention) In view of the above, the present invention provides a pledget made of a biodegradable polymer compound, which does not remain in the body after performing one function. Moreover, since it has excellent biocompatibility, it can be applied to delicate areas.

(Means for Solving the Problem) However, its characteristic feature is that it is a synthetic polymer material made of polyglycolic acid, which is a biodegradable and absorbable thermoplastic polymer, or a copolymer of this and lactic acid. The chips are melt-spun to make multifilament yarn, and the random web obtained from this is made into a nonwoven fabric, or multiple layers of knitted or woven fabric are layered and then needle punched to make a nonwoven fabric. It is a pledget that is finally heat pressed to remove fuzz and fraying, and finally cut into an oval shape of an appropriate size. Examples of the shape are:
As shown in Figure 1, make two needle holes (2) and (3) near the center of the oval cut piece.
1), and when it is used, a suture thread (4) is passed through the needle holes (2) and (3) during surgery as shown in FIG.

In addition, to give a specific example of the material constituting the present invention, it is possible to use polyglycolic acid and polygraftin 910, which have high biocompatibility and little inflammatory reaction, and which have already been used as absorbable suture threads. Combinations of similar genders are desirable for common use, however,
Application of these pledgets is also possible when using non-absorbable sutures.

Furthermore, the strength and hydrolysis rate can be controlled by the materials used and their combinations, but can also be controlled by stretching and heat treatment conditions at the yarn stage, or by hot pressing conditions after turning into a nonwoven fabric.

In addition, it is possible to obtain colored fibers by melt spinning by adding a dye that is harmless to the human body to the polymer chip before spinning, and if the fiber is white or a color close to white, it will be dyed red due to bleeding during surgery, making it difficult to distinguish. Pledgets colored in an appropriate color 1, for example, green or purple, have the advantage of being easy to distinguish during surgery, making the surgery easier.

(Function) As described above, the present invention is suitable for use in cases where the tension applied to suture threads in surgical operations may cause rupture of body tissue, that is, in cases of suturing soft or thin tissue or extensive anastomosis. When used as a thread, the tension applied only to the thread is dispersed by the pledget, reducing the possibility of damaging body tissues and increasing the reliability of suturing.

Furthermore, since it is hydrolyzable, it is absorbed into the body through the plugs that function as reinforcing materials, so it does not remain in the body as a foreign substance for a long time, and its absorption rate is low.

As mentioned above, it has characteristics that can be controlled arbitrarily by changing the polymer composition and manufacturing conditions.

The configuration will be explained below by giving an example.

(Example) [Production Example] The viscosity when dissolved in a solvent containing 7 parts trichlorophenol to 10 phenol, heated at 190°C for 3 minutes, then cooled to 30°C, and measured. M
2 polyglycolic acid chips with sp/c) of 1.5
Melt-spun at 45°C and stretched to 35 mm with 12 filaments.
I got a denier thread.

This was heat-treated at 106° C. for 3 hours and then knitted into a tube shape using a tube knitting machine.

This 4-ply knit is needle-punched to create a non-woven fabric with almost no visible stitches, and this non-woven fabric is then heat-pressed at 100°C for 5 minutes to prevent fuzzing and fraying, creating a material with uniformity and stretch. Configured.

This was cut into an oval shape of 3 mm x 8 mm, and two holes were punched near the center to make a pledget.

[Evaluation of the physical properties] 1n-vitr of the pledget obtained as described above.

It was used for hydrolyzability evaluation.

As shown in Figure 3, the tensile strength was measured when a single-return yarn (5) was inserted in a loop through the needle hole (3) of the pledget and a load (6) was applied to it. be.

in saline at 37°C for 3, 5, and 7 days, respectively.
The results were compared with the initial tensile strength after 14 days of immersion.
Shown in the table.

Table 1: According to the results, the tensile strength is almost the same as the initial strength up to the 5th day, and it gradually begins to decompose around the 70th day, becoming considerably weaker at the 14th day. It is fully functional.

[Practical Evaluation] The pledget constructed as described above was passed through the cervical trachea of an adult mongrel dog weighing 7 to 15 kg between the 7th and 8th tracheal cartilage, and the method shown in Fig. 4 was applied to both central and peripheral sides, that is, a needle was inserted. (7)
Using No. 4-0 Vicryl thread (trade name) as the attached suture (4), the membranous part was sutured in one place so that the entire thickness was sutured.
The tracheal cartilage was anastomosed end-to-end at five locations and joined as shown in Figure 6, and its progress was observed.

Note that (8) and (9) in the figure are the trachea.

1 and 2 weeks after the operation to check the condition of the anastomosis.

Experimental dogs were killed at 4 weeks, 2 months, 3 months, and 10 months.
Degradation and absorption rate of the material 2. Tissue reaction, loosening of the suture at the anastomotic site, and extent of pledget falling out were observed. still,
A reprinted Teflon pledget was used as a control.

As a result, the initial tensile strength of the material was 4.0 kgf, which is significantly higher than the Teflon pledget's 0.4 kgf, and the strength was maintained for up to one week under hydrolysis. 2i! ! Decomposition progressed rapidly after the frontage.

In the tracheal anastomosis experiment, in one case, the Teflon pledget used as a control fell off into the trachea 110 days after the operation, and the patient died of suffocation due to the granulation that had formed around it. When this was examined histologically, a strong tissue reaction occurred in the surrounding area.

It was found that the tracheal cartilage was partially dissolved and the Teflon pledget was encapsulated with connective tissue, resulting in a scar-like appearance. None of the polyglycolic acid pledget cases suffered from anastomotic failure due to anastomotic stenosis, pledget dislodgement, or thread loosening. Histologically, the polyglycolic acid pledget showed postoperative iii! ! Cells entered between the fibers of the material, causing the material to soften, expand, and be absorbed.However, there was little tissue reaction to the surrounding tissue during the decomposition process, and the material was decomposed and absorbed after three months.

(Effects of the Invention) As described above, the present invention has unprecedented features,
It is extremely suitable for use in reinforcing sutures in surgical operations.

In particular, the material used is polyglycolic acid and a copolymer of this and lactic acid, and the degree of polymerization,
Degradability can be controlled by adjusting the polymerization ratio.

In addition, in the manufacturing method, it is especially suitable to apply it as a non-woven fabric, but the non-woven fabric using a random web is not uniform in its density, and in this point, as mentioned in the examples, especially knitting, Layering multiple layers of woven fabric,
It is preferable to needle-punch this material to make it into a non-woven fabric, which has a uniform density, and also has appropriate elasticity in knitted fabrics, making it easy to adapt to the tissue to which it is applied.

[Brief explanation of the drawing]

FIG. 1 is a perspective view illustrating a pledget of the present invention. Second
The figure is a perspective view illustrating the state of use. FIG. 3 is a front view showing tensile strength evaluation, FIG. 5 is a front view showing the state of anastomosis of the trachea in the example, and FIG. 6 is a front view showing the state of anastomosis of the trachea in FIG. (1) - one - pledget (2) (3) - m - needle hole (4) - one suture (8) (9) - one trachea

Claims (1)

[Claims] 1. A medical pledget made from a biodegradable and absorbable thermoplastic polymer. 2. The medical pledget according to claim 1, wherein the biodegradable and absorbable thermoplastic polymer is polyglycolic acid. 3. The medical pledget according to claim 1, wherein the biodegradable and absorbable thermoplastic polymer is a copolymer of glycolic acid and lactic acid.