JP4407270B2 - Living body insertion catheter - Google Patents

Description

  The present invention relates to the configuration and structure of a living body insertion catheter that is inserted into a blood vessel, a lumen, etc. of a patient in order to introduce a medical instrument or a drug solution to a target site of an affected area or a treatment section for diagnosis or treatment. .

BACKGROUND OF THE INVENTION
A living body insertion catheter is a medical instrument composed of a tubular member inserted into a blood vessel or lumen of a living body for diagnostic or therapeutic purposes (hereinafter, the living body insertion catheter is simply referred to as a catheter). A catheter is inserted into a vascular structure such as a blood vessel and a lumen of a living body, and is used for various purposes such as diagnosis, treatment, drug administration, drainage, and irrigation. When a catheter is used for these purposes, the catheter is inserted into a blood vessel through an incision in the patient's skin, or inserted into a lumen such as the digestive tract, lymphatic tract, airway, urethra, etc. for diagnosis or treatment. Guide the distal tube portion of the catheter to the target site.

A catheter hub is attached to the end of the catheter shaft on the proximal side when inserted into the living body. This catheter hub is a guide wire used for inserting the catheter into the living body and guiding it to the target site in the living body. It serves as an insertion port for catheters such as therapeutic purpose devices and drug injection tubes.
A tip tube portion is bonded to the distal end side of the shaft portion into the living body, and a tip portion is further bonded to the tip end thereof.

The shaft portion of the catheter is the main part of the structure, and for insertion into the living body, followability (trackability) corresponding to complicated bending of blood vessels or lumens is required, and at the time of insertion of the catheter into the body Ease of pushing (pushability) and flexibility and slipperiness that do not damage living tissue are required.
The distal tube portion and the tip portion become the distal end portion of the catheter, and are required to be more flexible and flexible than the shaft portion so as to reach the affected area and the target site accurately.

  Conventionally, various types of these catheters have been prepared according to the required characteristics according to the intended use, and the corresponding configuration, structure, selection of members to be used, or studies for improving performance have been studied. A number of patents have been disclosed regarding catheters (see, for example, Patent Documents 1 to 6).

U.S. Pat. No. 4,976,690 U.S. Pat. No. 4,775,371 Japanese Patent No. 3343266 Japanese Patent No. 3115799 JP 2003-019025 A JP 2000-185103 A

The above patent relates to various improvements whose main purpose is to improve the performance of inserting a catheter into a living body.
On the other hand, in the treatment using a catheter, consideration for operability when the catheter is pulled out or removed from the body after the operation is also an important matter.
There is a need for improvements in the structure and structure of a catheter that can be reliably removed from the living body after treatment.

  When performing a treatment by inserting a catheter into a treatment site in the body, the flexible distal tube portion at the distal end of the catheter is inserted into a complexly bent blood vessel or lumen. When the catheter is pulled through the shaft portion after the treatment and pulled out of the body, a tensile load from the shaft portion is applied to the tip tube portion and the bonding portion between the shaft portion and the tip tube portion.

  The structure where the tensile load for removing the catheter does not concentrate directly on the bonded part because the tensile strength at the bonded part of the shaft part and the distal tube part is generally weaker than the tensile strength of the shaft part and the distal tube part itself. A catheter is desired.

  When the practitioner pulls the catheter out of the body, if the tip tube section is anchored or detected in the body, the practitioner inserts the catheter into the shaft without forcibly pulling the catheter in one direction. Push back in the direction, then pull back to the hand side. By repeating this, the anchoring of the distal tube portion into the body is released, and the catheter is removed from the body. An object of the present invention is to make it possible to better perform the operation of removing the catheter from the body.

In order to achieve this object, a living body insertion catheter according to claim 1 of the present invention includes a shaft portion and a tip tube portion made of a synthetic resin tubular member, and the tip tube portion is bonded to the shaft portion. In particular, the bonded portion between the shaft portion and the tip tube portion is provided with an elongated portion formed of a material having a lower yield point load value than the shaft portion and the tip tube portion. Features.
The biological insertion catheter according to claim 2 is the biological insertion catheter according to claim 1, wherein at least one of the shaft portion and the distal tube portion is made of a synthetic resin mixed with a contrast medium for X-ray viewing. The extension portion is configured so that the X-ray visual contrast medium is mixed in more than the synthetic resin in which the X-ray visual contrast medium is not mixed or the shaft portion or the tip tube mixed with the X-ray visual contrast medium. It is characterized by being comprised from a synthetic resin with few.

In the present invention, the catheter, interposed extension portion formed by the material of the lower yield point load value than the shaft portion and the tip tube portion between sheet Yafuto and distal tube portion, to produce an adhesive catheters.
By setting the extension part on the catheter, when a tensile load is applied between the shaft part and the tip tube part, the extension part is extended when this tensile load is applied above the yield point weight value of the extension part, It was possible to provide a relaxing action without concentrating the tensile load on the bonded portion having weak mechanical strength.
By applying the present invention to a catheter, the operability in removing the catheter to the outside of the body after the treatment using the catheter could be improved.

A configuration as an example of a catheter is shown in FIG. Reference numeral 1 is a proximal side, and includes a catheter hub serving as an insertion port for a guide wire and the like, a shaft portion 2, a distal end tube portion 4, and a state-of-the-art tip portion 6 connected thereto. The shaft portion 2 and the tip tube portion 4 are polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer, various synthetic resins such as polystyrene, polyamide, polyurethane, polyimide, or polyamide elastomer. Various elastomers such as polyester elastomers, polyurethane elastomers, polystyrene elastomers, and fluorine elastomers are used as constituent materials.

The shaft portion 2 is extruded into a tubular shape using the above-mentioned various synthetic resin materials, and pushability is required in addition to bendability depending on the intended use. Therefore, stainless steel, Ni-Ti alloy, etc. are present in the tube wall layer. A thin metal wire braid is inserted, and the synthetic resin layer is generally multi-layered. The distal end tube portion 4 is also extruded into a tubular shape using the above-mentioned various synthetic resin materials, and is flexible so that it can be inserted into a bent portion such as a blood vessel or a lumen in a living body. Various elastomer materials are also used. Is done. When it is necessary to visually confirm the insertion position of the catheter with X-rays, contrast agents such as BaSO ₄ and Bi ₂ O ₃ are mixed in these tubular members.

As for the catheter, a tubular member suitable for each function is prepared and used for both the shaft portion 2 and the distal tube portion 4. The mechanical properties of the tubular member are affected by the stretch orientation during the production of the tubular member and the hardening due to crystallization as well as the size, shape and material. In setting the extension part for such a tubular member, the extension part must be set in consideration of the setting site, the setting length, etc. so as not to impede the functions required of the catheter of the shaft part 2 and the tip tube part 4. .

The extension part for the shaft part 2 and the distal end tube part 4 is set by locally shielding only the extension part setting part by using a heat shield tube etc. other than the necessary part to meet the setting position and the setting length for the tubular member. It is carried out by heating.
In the local heating of the tubular member to be performed for the extension part setting, a thermally insulating ceramic, glass, heat-resistant synthetic resin tube is inserted to shield the non-heating part, and a gap is provided in the extension part setting part. An extended portion is set by exposing the exposed portion and heating the exposed portion.

Bonding of the shaft portion 2 and the tip tube portion 4 is performed by heating and pressure-bonding the bonding portion by various methods such as hot air, heater, radiant heat irradiation, high-frequency induction of the core metal material, and the like. The shaft portion 2, when setting an extension to either or both of the distal tube portion 4, it is also possible shall be the same time heated to extended portion an extension portion at the time of bonding the heating such as this. Alternatively, the elongated portion setting portion may be heated again after bonding to form an elongated portion.

The stretched and cured portion can be relaxed by heating the constituent synthetic resin material near its melting point temperature, and the orientation and hardening can be removed or reduced.
In the case of a crystallized resin, the degree of crystallinity can be reduced by heating the constituent synthetic resin material to a temperature higher than the crystallization temperature and quenching.

When a tubular member made of another member is attached and inserted between the shaft portion 2 and the distal tube portion 4 of the catheter as an extended portion, the tubular member of the extended portion is stretched and cured at the time of production by heat treatment. The orientation hardening is reduced or removed, and the crystallization is performed using an amorphous material or the crystallinity reduced by the above method. Moreover, the same kind of elastomer can be mixed and used in the various synthetic resin materials as different materials.

Next, the tensile test which assumed the adhesion part of a catheter was implemented as length determination of an expansion | extension part. The test piece is a polyamide-polyamide elastomer having an outer diameter of φ1.43 mm and an inner diameter of φ1.05 mm. One is mixed with 40 wt% BaSO ₄ and a stainless steel braided three-layer tube, and the other is mixed with Bi ₂ O ₃ 40 wt%. The end portions of both were overlapped by 0.5 mm and melt welded. The test piece had a length of 25 mm on one side and a total length of 50 mm, and an extension portion was set to a portion adjacent to the welded portion of the single-layer tube corresponding to the tip tube portion over a length of 0 mm to 20 mm. The distance between chucks of the tensile tester is fixed to 30 mm, and the speed is 200 mm / min. A tensile test was performed.

FIG. 2A shows the tensile test results using the tip tube portion 4 without the extension portion as a test piece. The vertical axis represents the tensile load, and the horizontal axis represents the displacement up to breakage due to tension. In this case, after displacement by 3.4 mm, the welded portion was broken at a tensile load of 14.3 N.

FIG. 2B shows the result of taking the tensile load and displacement until the fracture in the tensile test using the tip tube portion 4 provided with the extension portion having a length of 5 mm as a test piece. When the applied tensile load reached about 14N of the yield point load of the extended portion, the extended portion started to expand, the extension in this extended portion reached 33.4 mm, and fractured at the weld location with a tensile load of 15.4N. As shown in this figure, there is almost no elongation at the extension part until the extension start point 14N, as shown in this figure. When this point is reached, extension of the extension part starts, and along with the gradual increase of the tensile load, The elongation displacement increased, and when the tensile load reached the welding strength, it broke at the welding location.

The mechanical strength of the elongated portion is lower by an amount corresponding to the removal of stretched orientation and hardening than the tip tube portion main body. When a tensile load is applied to the specimen, the stretched part will withstand the yield point of this mechanical strength in the same way as the other parts. When the tensile load reaches this yield point load, the extension starts to expand. As the synthetic resin material elongates, the polymer in the synthetic resin material is oriented in the elongated portion, and the elongation is continued while the application of the tensile load and the orientation hardening are balanced. Thereafter, when the tensile load reaches the welding strength at the welding location, the welding location breaks.

FIG. 3 (a) shows the measurement results of the relationship between the length of the extended portion and the breaking load due to tension, with respect to the tip tube portion 4 of the test piece set by changing the length of the extended portion from 0 mm to 20 mm. It was. Fracture occurs at any bonded portion, the breaking load is a length corresponding to orゝWarazu 15N around values of extension portion.
FIG. 3B shows the relationship between the extension displacement of the extension part up to the breakage due to the application of a tensile load in this experiment and the set length of the extension part.
In the case where there is no setting of the extension part, the extension displacement in the tensile test is almost 3.4 mm, but there is almost no extension, but when the extension part becomes 5 mm or more, the extension displacement reaches 33 mm, and after that, regardless of the length of the extension part, about 35 mm This is the extension displacement.

Based on the above experimental results, in setting the extension part to the catheter, its performance is not hindered according to the shape, dimensions, material, etc. of the shaft part and tip tube part constituting the catheter, such as the setting part, setting length, etc. Thus, the extension part is set.
In setting the extension part, the extension displacement shows almost the same value as the extension part in the experimental range, so that the degree of freedom in setting the extension part is large, and the setting of the extension part is considered easy.

The above is the result regarding the setting of the extension part according to one example, and as described, there are various types of dimensions, shapes, and constituent materials for the catheter, so appropriate extension part setting according to each is preferable, and stick to the above example It is assumed that it is arbitrarily selected.

Hereinafter, the present invention will be described by way of examples. However, the present invention is not limited to only the examples shown below.

It is an Example of this invention to the thing of the structure of FIG. 1 as a catheter. The shaft portion 2 in FIG. 1 is a tubular member having a length of 950 mm, and a material obtained by mixing 40 wt% of BaSO ₄ into a mixed material of polyamide and polyamide elastomer. That is, the lower layer of the synthetic resin material was extruded into a tubular shape, a stainless steel fine wire was braided thereon, and the synthetic resin material was extruded into two layers as an upper layer on the braid 3 and coated. The thickness was 0.2 mm, the outer diameter was φ1.4 mm, and the inner diameter was φ1.0 mm in the three-layer molding with the braided material.

The distal end tube portion 4 is a tubular member having a total length of 30 mm, and a mixture of polyamide and polyamide elastomer mixed with 40 wt% Bi ₂ O ₃ is used as a raw material, and is extruded into a single layer. A tip portion 6 was welded to the most distal side of the catheter. The tip portion 6 has a length of 1.0 mm and is made of the same material as the tip tube portion 4, but is made more flexible.

A distal end tube portion 4 is welded to the distal end side of the shaft portion 2 to obtain a welded portion 5. At the welding location 5, the welding ends of the shaft portion 2 and the tip tube portion 4 were overlapped with each other by 0.5 mm and welded. In this welding, each synthetic resin was heated and melted to the melting point or more, and at the same time, an external pressure was applied to the overlapped portion from the outer periphery so as to have the same diameter as the other portions.
In the present example, an extension portion having a length of 5 mm was adjacent to the welding location 5 and heated at the same time as the welding. Since this heat treatment is performed by limiting the heating range, the heat insulating ceramic tube is extrapolated, the portion outside the heating range is shielded, the welded portion 5 and the elongated portion are exposed, and the heating is performed locally by radiant heat irradiation. did.

By the local heating of the tip tube portion 4 adjacent to the welded portion 5, the stretch orientation hardening was removed from the tip tube portion 4 and an extension portion could be set. In the next step, the distal tube portion 4 was provided with a shape in accordance with the specification of the catheter by inserting and heating a core metal for shaping the distal end shape. Next, the catheter hub 1 was adhered to the proximal end of the shaft portion 2 to complete the assembly of the catheter.
The setting part of the extending part in the present embodiment is shown in FIG. Reference numeral 7 shown in FIG.

A tensile test was performed through the welded portion 5 and the elongated portion 7 of the shaft portion 2 and the distal tube portion 4 of the catheter produced in this example. The result of the tensile test almost coincided with the result of FIG. The tensile load was applied to the welded portion 5 after the elongated portion 7 set in the distal tube portion 4 was elongated by about 35 mm, and the direct application of the tensile load was relaxed.

In this embodiment, both ends of the shaft portion 2 and the tip tube portion 4 are not directly welded, and a tubular member having a good elongation characteristic is interposed between them or one of them as an extension portion. It was.
The catheter was applied to the same catheter as in Example 1. The material of the extension portion is made of the same kind of synthetic resin as that of the shaft portion 2 and the tip tube portion 4 and the mixed amount of Bi ₂ O ₃ mixed in the tip tube portion 4 is reduced from 40 wt% to 20 wt%. Used for.

By reducing the amount of Bi ₂ O ₃ mixed into the elongated portion from 40 wt% to 20 wt%, the elongation characteristics are improved, and the synthetic resin material is the same as the shaft portion 2 and the tip tube portion 4. As a result, welding between the elongated portion and each of the shaft portion 2 and the tip tube portion 4 was also easily performed. The tubular member serving as the elongated portion had the same diameter and the same thickness as the shaft portion 2 and the tip tube portion 4, and the length thereof was 5 mm in this case as well, and was inserted between them.
In this case, although the welding conditions for each were slightly different, welding was possible by heating and pressurization at the same temperature, and the tubular member of the elongated portion was also reduced and removed by stretching heating at this time.

FIG. 5 shows the structure of the elongated portion in this example. In FIG. 5, reference numeral 8 denotes a tubular member serving as an elongated portion. In the tensile test between the shaft portion 2 and the tip tube portion 4, the elongation portion 8 extends to the fracture at the welded portion, and the same behavior as in the above example is observed. Indicated.

In the catheter of the present invention, it is possible to prevent the tensile load when being extracted from the living body from being concentrated on the adhesion portion between the shaft portion and the tip tube portion, and to perform the extraction operation satisfactorily.

Configuration diagram of catheter for living body insertion The graph which showed the tensile test result of (a) which set the extension part of length (a) which does not set an extension part in a tip tube part, and (b) which welded a shaft member and a tip tube part A graph showing the tensile test results of a test piece in which a shaft member and a tip tube member are welded and an extension portion is set to the tip tube portion by changing the length from 0 mm to 20 mm. (A) Set length of extension portion and tensile breaking load (B) Elongation displacement until the set length of the extension and the tensile break Partial enlarged view of the elongated portion set by welding the shaft member and the tip tube member and removing the orientation hardening in the tip tube portion adjacent to the welding location. Partial enlarged view of the extension provided as a separate member between the shaft and the tip tube

DESCRIPTION OF SYMBOLS 1 Catheter hub 2 Shaft part 3 Stainless steel thin wire braid in shaft part tube wall layer 4 End tube part 5 Adhesion location 6 Tip part 7 Extension part which removed orientation hardening 8 Extension part which reduced X-ray contrast agent mixing amount

Claims (2)

A living body insertion catheter comprising a shaft portion and a tip tube portion made of a synthetic resin tubular member, wherein the tip tube portion is bonded to the shaft portion,
A living body insertion catheter comprising an elongated portion formed of a material having a lower yield point load value than that of the shaft portion and the tip tube portion at a bonding portion between the shaft portion and the tip tube portion . At least one of the shaft portion and the tip tube portion is composed of a synthetic resin mixed with an X-ray visual contrast agent ,
The extension portion is a synthetic resin in which the contrast agent for X-ray viewing is not mixed, or the amount of the contrast agent for X-ray viewing is less than that of the shaft portion or the tip tube mixed with the contrast agent for X-ray viewing. The living body insertion catheter according to claim 1 , which is made of resin .

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