JPH06178812A - Introducer sheath - Google Patents

Abstract

PURPOSE:To obtain an introducer sheath (sheath dilator assembly) which enables the prevention of damage and danger when a sheath is left while the minimizing of the invasion into an intracorporeal tissue of a patient. CONSTITUTION:A dilator 11a is inserted into a sheath 22 and is so arranged to allow the tip thereof to stick out of the tip part of the sheath. An introducer sheath thus obtained is used as aid to insert a catheter and other apparatuses into a body. The tip part of the sheath 22 is made up of a body heat-softening part 22a adapted to be softened by body heat.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an introducer sheath, and more particularly to a sheath (hereinafter referred to as "sheath") used for assisting insertion of a catheter and other devices into a body, particularly a blood vessel, and inserted therein. The present invention relates to an introducer sheath formed by a sheath / dilator assembly in which a stepped recess is provided at the tip of a dilator (hereinafter referred to as “dilator”) and the tip of the sheath can be embedded in the recess of the dilator. It is a thing.

[0002]

2. Description of the Related Art An introducer sheath is a sheath dilator assembly in which a dilator is inserted into the sheath and the tip of the tapered dilator projects from the tip of the sheath. A general assembly appearance is shown in FIG. In addition, an enlarged cross-sectional view of the tip is shown in FIG.
Shown in. In both figures, a dilator 11 having a hollow portion 10 has a tapered taper end projecting from the tip of the sheath 12. Therefore, the sheath 1
There was a step 13 between the tip of 2 and the dilator 11. When the step 13 passes through the skin, the subcutaneous tissue and the blood vessel wall, it becomes a great obstacle, not only increasing the resistance of insertion, but also causing pain and discomfort to the patient.

In order to improve this point, the step 13 described above is used.
A structure for eliminating the problem is proposed, for example, Japanese Patent Publication No. 4471
No. 2 and Japanese Utility Model Laid-Open No. 3-15534. In principle, these are of the structure shown in the schematic cross-sectional views of FIGS. 7 and 8, and eliminate the step 13 between the sheath 12 and the dilator 11 shown in FIG. The structure is used to obtain the transition part. That is, the dilator is a dilator 11a having an annular recess 14 at the boundary between the tip of the dilator and the sheath 12, and the tip of the sheath 12 is embedded in the recess 14. By making the whole portion of the dilator covered by the sheath indented, the outer diameter of the sheath shown in FIG. 7 can be made smaller than that of FIG. 8 having the recess 14 only at the tip portion, which is a further improvement. . Both are characterized by eliminating the step 13 shown in FIG.

The purpose of indwelling the sheath in the body or in the blood vessel is to secure a passageway for the sheath lumen and to smoothly insert various catheters and equipments using this passageway. Therefore, the sheath is made of a material having a relatively high rigidity, which is inevitably difficult to be bent by bending and is hard to be crushed by pressure from the outer circumference.

[0005]

Since the above-mentioned conventional introducer sheath is made of a relatively rigid and highly rigid material, when the sheath is left in the body, especially in the blood vessel, the tissue that comes into contact with the tip of the sheath. The part will be damaged by pressure and abrasion. In particular, in the case of blood vessels, there is a problem that the intimal detachment occurs, and in the case of significant cases, there is even a risk of vascular wall perforation.

The present invention has been made to solve the above-mentioned problems, and it is possible to prevent the above-mentioned damages and risks and to prevent the invasion of the internal tissues of the patient to a minimum. Can introducer sheath (sheath
It is intended to provide a dilator assembly).

[0007]

In the introducer-sheath according to the present invention, a dilator is inserted into the sheath, and the tip of the dilator is configured to be capable of projecting from the tip of the sheath. An introducer used as an auxiliary device to be inserted into the body, wherein the distal end portion of the sheath is hard at room temperature and is made of a material that is softened by heating at body temperature, for example, a shape memory resin. Further, the dilator having an annular recess near the tip of the introducer sheath of claim 1 and the tip of the sheath are engaged with each other through the annular recess to eliminate a step between the dilator and the sheath. A sheath having a tip opening inclined with respect to the tube axis of the introducer sheath according to claim 2 and a dilator having a recess capable of being fitted and engaged with the tip opening are combined, and the tube axis is centered on each other. The dilator can be easily pulled out from the sheath by twisting.

[0008]

In the present invention, the distal end portion of the sheath is formed of a material that is hard at room temperature but softens when heated to a body temperature (body temperature softening material). When the Ducer sheath is inserted, only the dilator is extracted immediately after the insertion and only the distal end of the sheath remains in the blood vessel, for example.
In such a state, for example, even if the blood vessel wall moves due to body movement or pulse and rubs against the sheath tip, the tip is heated by the body temperature, so it is a sufficiently soft tip. , Minimize damage to tissue. The above-mentioned body temperature softening material is a shape memory type resin material which has a characteristic of being rapidly softened at a temperature equal to or higher than the body temperature and reversibly cured when the temperature returns to the body temperature or lower.

[0009]

【Example】

(Embodiment 1) FIG. 1 is a cross-sectional explanatory view of an introducer sheath, in particular, the tip portion thereof showing an embodiment of the present invention.
2 is a cross-sectional view showing the distal end portion of the sheath shown in FIG. As is apparent from FIG. 2, the sheath 22 is formed of two parts, a hard part 22b made of the same material as that of the conventional sheath 12 and a body temperature softening part 22a constituting the tip part thereof. Then, as shown in FIG. 1, the dilator 11a (see FIGS. 7 and 8) is inserted into the sheath 22, and the distal end portion of the dilator 11a is projected from the distal end portion of the body temperature softening portion 22a of the sheath 22. , Is assembled in the same manner as the conventional method.

The sheath 22 is bent at the time of insertion / dwelling in the body and has a length sufficient to extend to the distal end of a hard portion 22b made of a relatively hard material having a rigidity sufficient to secure a circular passage (lumen) against pressure. The body temperature softening portion 22a, which is hard at room temperature of several mm to several tens of mm, is joined or formed as a tip soft tip portion. Here, the body temperature softening part 22a and the hard part 22
Although various pairs can be considered as the combination of the materials of b, for example, the following combinations are suitable in the case of the introducer sheath. Hard part material Body temperature softening part material Polyurethane (hard) Polyurethane-based shape memory resin ^* * See Japanese Unexamined Patent Publication No. 61-293214 (Sanryo Heavy Industries KK trademark: Diary)

The joining is carried out by preparing a hard portion (hard polyurethane) of the sheath body having the same inner and outer diameters and a material (polyurethane shape memory resin) of the body temperature softening portion of the tip soft tip portion and using an adhesive and a solvent. Other methods include overlapping the joints and covering them with a heat-shrinkable tube, then immersing them in a heat medium and melting and compressing them to join, or inside the heating mold that regulates the outer diameter and outer diameter. It is possible to employ various known methods, such as a method of melting and joining together.

Combining the tip flexible sheath manufactured by the above-described method, that is, the sheath 22, with the dilator 11a which is pre-positioned and dented so that the tip portion of the sheath 22 is fitted in the dent 14 of the dilator. Thus, the desired sheath dilator assembly, that is, the introducer sheath according to the present invention is obtained.

The introducer sheath inserted into the body or the blood vessel by the operator removes only the dilator immediately after the insertion and leaves only the tip of the sheath in the blood vessel, for example. In this detention state,
For example, even if the blood vessel wall moves due to body movement, pulse, etc., and it rubs against the sheath tip, the tip soft tip is sufficiently soft due to the softening of the body temperature, so damage to the tissue can be minimized. The effect of being able to be obtained is obtained.

(Embodiment 2) FIGS. 3 and 4 are schematic explanatory views showing another embodiment of the present invention, FIG. 3 is a sectional view of an essential part, and FIG. 4 is a side view of FIG. As is clear from both figures, the sheath 22 is composed of a hard portion 22b and an inclined body temperature softening portion 22c which constitutes the distal end portion thereof. The tip of the inclined body temperature softening portion 22c forms an inclined tip end opening 23 having a shape cut obliquely with respect to the tube axis of the sheath. Therefore, the dilator 11b has the inclined tip end 2
3 is formed so as to have a slanting annular recess 15 that engages with 3. That is, at the portion of the oblique annular recess 15, the dilator 11b is inserted through the inclined tip end opening 23.
Is fitted and engaged with the sheath 22.

In the structure of the second embodiment, since the dilator and the sheath are fitted and engaged with each other at the inclined distal end port 23 as described above to set the normal state, the dilator and the sheath are set around the pipe axis. By twisting, the dilator 11b can be pulled out from the sheath 22 more easily than in the first embodiment.

[0016]

As described above, according to the present invention, the tip of the sheath is made of a body temperature softening material which is hard at room temperature but softened by heating by the body temperature, and the sheath body is made of a hard material similar to the conventional one. Since we have developed an introducer sheath consisting of a sheath-dilator assembly formed as a flexible sheath, for practical use, for example, after inserting this into the body, especially inside the blood vessel, only the dilator is removed, and only the sheath tip is removed. Even when it is left in the blood vessel for normal use, even if the blood vessel wall moves and rubs against the sheath tip due to body movement, pulse, etc., the sheath tip portion is softened while it is in the body due to temperature softening. The effect of minimizing damage to the tissue is obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing an embodiment of an introducer sheath of the present invention.

FIG. 2 is a cross-sectional view illustrating a main part of a sheath of the present invention.

FIG. 3 is a cross-sectional view of an essential part showing another embodiment of the present invention.

FIG. 4 is a side view of FIG.

FIG. 5 is an assembled appearance view of a conventional general introducer sheath.

6 is an enlarged cross-sectional view of the tip portion of FIG.

FIG. 7 is a cross-sectional view of a main part of a conventional introducer sheath without steps.

FIG. 8 is a cross-sectional view of essential parts showing an improved type of the conventional example of FIG.

[Explanation of symbols]

 10 hollow part 11,11a, 11b dilator 12,22 sheath 13 step 14 dent 15 dent 22a body temperature softening part 22b hard part 22c slope body temperature softening part 23 slope tip end

Front Page Continuation (72) Inventor Hiroyuki Matsumoto 5-7-27 Sendagaya, Shibuya-ku, Tokyo Nihon Brunswick Building 5F Nihon Sherwood Co., Ltd.

Claims (3)

[Claims] 1. An introducer in which a dilator is inserted into a sheath, the tip of the dilator is configured to be capable of projecting from the tip of the sheath, and which is used as an auxiliary device for inserting a catheter and other equipment into the body, An introducer sheath, wherein the distal end portion of the sheath is made of a material that is hard at room temperature and softens when heated at body temperature. 2. The dilator having an annular recess near the tip and the sheath tip are engaged with each other through the annular recess to eliminate a step between the dilator and the sheath. Introducer sheath described. 3. A structure in which the sheath having a tip opening inclined with respect to the tube axis and the dilator having a recess capable of being fitted and engaged in the tip opening are combined, and twisted with each other about the tube axis. The introducer sheath according to claim 2, wherein the dilator can be pulled out from the sheath.