JPH06335531A - Introducer - Google Patents

Abstract

PURPOSE:To prevent the peeling of the front end of a sheath at the time of insertion of the introducer for medical purposes formed by combining a director with the sheath by specifying the structure of a part where the sheath and the director come into contact and bringing the foremost end of the sheath into elastic tight contact with the outer peripheral surface of the director. CONSTITUTION:The introducer for medical purposes which is insertable into the endotissues without damaging the tissues is constituted by fitting the director 4 into the sheath 1 consisting of an elastic high polymer having <=0.1% residual permanent set at 5% elongation for 10 minutes at room temp. The sheath 1 is so formed that its front end 3 integrally has the foremost end 2 of a sharp angled wedge-shaped section. The bore of this foremost end 2 is set at a size smaller than the outside diameter of the director 4 before the director 4 is not yet fitted. As a result, the foremost end 2 of the sheath 1 is expanded in diameter when the director 4 is fitted into the sheath 1. The foremost end 2 of the sheath is brought into tight contact with the director 4 by the recovering elasticity generated at this time at >=1mm in the state of lightly tightening the periphery of the sheath.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medical introducer in which a sheath and a dilator are combined.

[0002]

2. Description of the Related Art Conventionally, a dilator 4 is inserted in a sheath 1.
An introducer is used in which the above are fitted and combined as shown in FIG. In such a combination, the sheath is usually made of a hard resin such as Teflon. However, when inserting the introducer into a blood vessel or the like, the hard resin sheath does not bend smoothly in a curved shape, but there is a drawback that the straw is suddenly angled and linearly bent (kinked) so that the straw breaks, For smooth insertion of the sheath, it is desirable that the shape is curved to some extent. However, when a flexible flexible resin is used, the tip of the sheath now forms a step with the surface of the dilator, so the tip may float up due to the resistance that hits the step, or it may turn over greatly, causing the wall of the blood vessel to move. May cause damage to internal tissues.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an introducer equipped with a flexible sheath that can be smoothly inserted without damaging internal tissues. More specifically, when a flexible sheath without kink is used, it is possible to solve the problem that the distal end of the sheath is turned over from the dilator surface during insertion, which makes it difficult to smoothly insert it into a body tissue such as a blood vessel. With the goal.

[0004]

As a result of earnest research, the inventors of the present invention have succeeded in solving the above-mentioned problems by forming a specific structure in the contact portion between the sheath and the dilator in the tip portion of the introducer. . That is, the present invention is an introducer in which a dilator is fitted to a sheath made of an elastic polymer material having a residual permanent strain of 0.1% or less at 5% elongation for 10 minutes at room temperature. Has a tip portion that becomes thinner in thickness toward the tip of the sheath, and the diameter of the tip of the sheath is smaller than the outer diameter of the portion corresponding to the dilator, and when the dilator is fitted into the sheath. Further, the present invention provides an introducer characterized in that the distal end of the sheath is in close contact with the outer peripheral surface of the dilator by the restoring elasticity of the sheath tip over a length of 1 mm or more in the longitudinal direction. The sheath used in the present invention is made of an elastic polymer material, which has no residual strain after 5% stretching for 10 minutes at room temperature, that is, 0.1% or less, preferably 0.01% or less. Can be used. Further, those having a Shore hardness of A80 or more and a Shore hardness of D65 or less are preferably used. If the Shore hardness is lower than the above range, the shape is not stable, and the tip portion is likely to be turned upside down. In some cases, it is possible to use a sheath having a hardness higher than that of the middle portion only at the distal end portion. On the other hand, if the Shore hardness is too hard than the above range, the sheath loses flexibility and becomes a kink-prone sheath similar to the conventional Teflon resin. If a material with a residual permanent strain that easily creeps is used, when the introducer is installed inside the body, the tightening elasticity of the close contact part of the sheath tip part disappears and the tip of the sheath moves from the dilator surface. There is a risk of rising. As the material used for the sheath in the present invention, for example, polyurethane, nylon, low density polyethylene, polyisoprene rubber, etc. can be used. The introducer of the present invention will be described in more detail with reference to the drawings of the embodiments. The tip portion of the sheath of the introducer of the present invention is such that the tip portion 3 of the sheath has a wedge-shaped acute tip portion 2 as shown in the sectional view of the tip portion of FIG. As you head
The thickness of the sheath 1 becomes thinner in a tapered shape. The inner diameter A of the sheath tip 2 is formed smaller than the outer diameter of the dilator when the dilator is not fitted. As a result, when the dilator 4 is fitted to the sheath 1,
The tip 2 of the sheath is expanded and its restoring elasticity causes the tip 2 of the sheath to lightly clamp the outer circumference of the dilator 4 and closely contact the outer circumference of the dilator. The close contact needs to be 1 mm or more along the longitudinal direction of the introducer. If it is less than 1 mm, the tip 2 will be broken or lifted, and it will not slide smoothly on the surface of the dilator 4. In this embodiment, the inner diameter of the sheath 1 is slightly larger than the outer diameter of the dilator 4, and the inner surface of the sheath 1 and the dilator 4 are
The contact is gentle enough to form a slight gap 7 with the outer surface of the. For this purpose, the inner diameter of the sheath 1 is
The outer diameter of the dilator 4 can be increased by about 0.05 to 0.5 mm. By making the contact between the sheath and the dilator gentle by this gap 7, the friction between both surfaces is reduced, and the dilator 2 can be slid smoothly in the sheath 1.

As another aspect of the present invention, as shown in FIG. 3, the shape of the tip end portion of the dilator in contact with the sheath tip 2 is devised to insert a thick step at the tip 2 of the sheath 1. There is an introducer that has a function of reducing the resistance and preventing the distal end 2 of the sheath 1 from rising. Figure 3
When the dilator 4 is fitted to the sheath 1, the embodiment of the embodiment of the present invention is a position slightly before the tip of the dilator 4 and just outside the dilator 4 from the position where the distal end 2 of the sheath 1 comes just. The diameter decreases in a taper shape as it approaches the dilator, and the taper thickness at the tip of the sheath 1 having the same outer diameter as the outer diameter of the tip of the dilator 4 reduces the outer diameter of the dilator 4. Overlap to compensate, and as a result, the outer diameter of the tip portion of the dilator 4 is 1
It is equivalent to inserting a book tube. Even if the tip 2 of the sheath does not exactly coincide with the start point of the taper-shaped decrease of the dilator as shown in FIG. 3, if the tip of the sheath has a taper-like inclination, the same effect as in FIG. 3 is exhibited. To do. In this case, the diameter of the tip 2 of the sheath 1 is set to be smaller than the outer diameter of the dilator at the contact position, the tip 2 lightly clamps the outer circumference of the dilator by the restoring force, and the width of the dilator is 1 mm or more. It adheres to the outer circumference. Further, the inner diameter of the sheath is made slightly larger than the portion of the dilator where the outer diameter is reduced, which occupies most of the entire length of the dilator, to ensure smooth sliding of the dilator in the sheath. In the same technical idea, the embodiment of FIG. 4 has a configuration in which the outer diameter of the tip of the dilator 4 gradually decreases gradually toward the hand and then returns to the original outer diameter again from the side as shown in FIG. As seen, the recessed portion 5 is formed. In the embodiment introducer of FIG. 4, when the sheath 1 having an inner diameter slightly larger than the outer diameter of the dilator 4 is fitted onto the dilator 4, the distal end 2 of the sheath 1 is a recess of the dilator 4 of FIG. It is set so as to come to the position of 5. If the position of the tip 2 of the sheath is located within the range of the length of the recess 5, it is behind the thick outer diameter of the tip of the dilator, and the resistance applied to the tip 2 of the sheath disappears. By doing so, the step at the tip 2 of the sheath is hidden by the recess 5 at the outer circumference of the tip of the dilator 4 during insertion operation of the introducer, and no resistance is received. There is no fear. Also in this aspect,
The diameter of the most distal end of the sheath 2 is smaller than the diameter of the position where the indentation 5 comes into contact with each other, and the point of tight contact with a width of 1 mm or more is the same as in the embodiment of FIG. As another aspect of the present invention, as shown in FIG. 5, there is an aspect in which the tip of the dilator 4 is thinned and a tapered slope 6 is formed near the tip. The tapered slope 6 is provided at a position slightly closer to the tip end side of the dilator than the position where the dilator and the distal end of the sheath are in contact with each other, and the angle β of the tapered slope 6 of the dilator 4 is equal to the tapered thickness of the distal end of the sheath. Greater than the angle α formed from the tip,
The most advanced sheath 2
It has been confirmed by experiments that the step of (4) is hidden behind the dilator 4 in the direction of the tapered inclination 6 so that the resistance is not suspended and the same curl prevention effect as in the case of FIG. 3 is obtained. Also in this case, the diameter of the tip 1 of the sheath 1 and the inner diameter of the sheath 1 are set in the same manner as in FIG. 2, and the contact width of the tip of the sheath is 1 mm or more. Further, the sheath distal end portion 3 can be made harder than the other portions of the sheath so that the sheath distal end can be prevented from being turned over and the insertion can be facilitated. In this case,
As a method of hardening, for example, a material harder than the material of the other part is used as the material of the tip portion, and it may be heat-fused. You can When the sheath material is polyurethane resin, polyol is used as a curing agent,
Polyisocyanate, fluorine gas, or the like can be reacted only at the tip and cured by a crosslinking reaction.
In the case of a hydrocarbon resin, the peroxide solution can be cured immediately by impregnating the tip of the sheath with heat and heating. Further, only the tip portion can be hardened by the method of filling the tip portion of the sheath mold with the hard resin and then the soft resin.

[0006]

According to the introducer of the present invention, the sheath thereof is made of a soft, flexible, elastic, shape-stable, and non-kinking material, and has a specific structure at the tip of the sheath and the tip of the dilator. As a result, it has been achieved that the distal end of the sheath does not rise or turn over, which has the advantage of smooth insertion.

[Brief description of drawings]

FIG. 1 is a side view of an introducer according to an embodiment of the present invention.

FIG. 2 is a sectional view of an introducer according to an embodiment of the present invention.

FIG. 3 is a sectional view of an introducer of another embodiment of the present invention.

FIG. 4 is a sectional view of an introducer of another embodiment of the present invention.

FIG. 5 is a sectional view of an introducer of another embodiment of the present invention.

[Explanation of symbols]

 1 sheath 2 tip of sheath 3 sheath tip 4 dilator 5 indentation 6 taper inclination 7 gap

Claims (5)

[Claims] 1. An introducer comprising a dilator fitted to a sheath made of an elastic polymer material having a residual permanent strain of 0.1% or less at 5% elongation for 10 minutes at room temperature. , The tip of the sheath has a taper that becomes thinner toward the tip of the sheath, and the diameter of the tip of the sheath is formed smaller than the outer diameter of the portion corresponding to the dilator, and when the dilator is fitted into the sheath. An introducer characterized in that, at the most distal end of the sheath, the sheath is in close contact with the outer peripheral surface of the dilator by a restoring elasticity of the sheath tip over a length of 1 mm or more in the longitudinal direction. 2. The outer diameter of the dilator gradually decreases from the tip of the dilator toward the hand at the position where the distal end of the sheath is in contact with the outermost diameter of the dilator. The introducer according to claim 1, characterized in that the introducer is housed in a reduced portion. 3. The dilator tip is tapered at a steep angle at a position slightly on the tip end side of the dilator from the position where the tip of the dilator and the sheath are in contact with each other, and the inclination angle of the dilator is tapered. The introducer according to claim 1, wherein the introducer is larger than an angle formed by a tapered thick tip at the most distal end of the sheath. 4. The introducer according to claim 1, 2 or 3, wherein the inner diameter of the sheath is formed to be slightly larger than the outer diameter of the dilator over substantially the entire length of the sheath. 5. The introducer according to claim 1, 2, 3 or 4, wherein the material of the distal end portion of the sheath is hardened.