CN117959561A - Stay wire for adjustable bent catheter, threading method and fixing method - Google Patents

Abstract

The application provides a stay wire for an adjustable bent catheter, a threading method and a fixing method, wherein the stay wire is made of aromatic polyamide fibers, is of a multi-strand twisting structure and has a diameter of 0.1-0.35 mm. The adjustable bending conduit wire is twisted by aromatic polyamide fiber, compared with a metal wire, the tensile strength and bending elongation of the aromatic polyamide fiber wire are the same as those of the metal wire, the fatigue resistance and flexibility of the adjustable bending conduit wire are superior to those of the metal wire, the bending force of the adjustable bending conduit can be reduced by using the aromatic polyamide fiber wire, and the bending flexibility of the adjustable bending conduit is greatly enhanced. Compared with other common high polymer polyester fibers, the aromatic polyamide fiber has the characteristics of high temperature resistance and stable chemical property, is convenient for fixing and welding the aromatic polyamide fiber stay wire on the adjustable bending catheter, can not deform due to high-temperature processing of the adjustable bending catheter, and can keep the integrity.

Description

Stay wire for adjustable bent catheter, threading method and fixing method

Technical Field

The application relates to the technical field of medical instruments, in particular to a stay wire for an adjustable bent catheter, a threading method and a fixing method.

Background

As an interventional medical device, a medical adjustable bend catheter often needs to be subjected to bending control when in use. Bending control may be achieved by tightening and loosening the pull wires located in the distal bending sections of the respective tubes. The wires may be arranged in pairs, one on each of the two radially opposite sides of the distal bending section, which may bend towards the wire-tightening side by tightening one of the wires and loosening the other.

Through single or many pre-buried stay wire cavities in the medical adjustable curved pipe wall, will stay wire one end is fixed at the pipe head end again, and the cavity other end stretches out from the pipe afterbody of passing to stay wire, then pulls and draws the curved function of realizing unidirectional or multidirectional accent. In order to ensure the strength of the stay wire and the convenience of fixing at the head end of the catheter and penetrating the stay wire into the stay wire cavity, the elongation of the stay wire is as small as possible when the stay wire is pulled, and single-strand or multi-strand metal wires are generally selected as the stay wire. However, for some microcatheter adjustable elbows, intracardiac ultrasound catheters, or other catheters with strict bending adjustment performance in the actual use process, the flexibility of the catheter bending adjustment is required, and the performance requirements of the metal stay wires are often not met. Because the metal wire has certain inherent rigidity, the metal wire is easy to rebound after being bent in the bending process of the bending-adjustable catheter, not only the flexibility of the catheter is reduced, but also the bending force of the bending adjustment of the catheter is increased, and the metal wire can scratch the catheter body during bending adjustment, so that the function of the catheter is seriously lost.

Disclosure of Invention

The application provides a stay wire for an adjustable bent catheter, a threading method and a fixing method, which solve the problems that the flexibility of the catheter is reduced and the catheter is even damaged due to rebound of a metal stay wire after bending in the bending process of the adjustable bent catheter.

In a first aspect, the application provides a stay wire for an adjustable bend catheter, wherein the stay wire is an aromatic polyamide fiber, the stay wire is of a multi-strand twisting structure, and the diameter of the stay wire is 0.1-0.35 mm.

In one possible implementation, the difference between the diameter of the pull wire lumen of the adjustable bend catheter and the diameter of the pull wire is greater than or equal to 0.05mm.

In one possible implementation, each single strand portion of the pull cord is a bundle of long fibers, the number of long fibers per bundle is 72-144, and the number of turns of the pull cord is 4-8 per inch.

In a second aspect, the present application provides a threading method for a pull wire of an adjustable bend catheter, wherein the pull wire of the first aspect is threaded into a pull wire cavity reserved in the adjustable bend catheter by using an air-assisted manner.

In one possible implementation, the threading method includes:

Fixing a preset die at the head end of the adjustable bent conduit, and feeding compressed air through an air inlet of the preset die;

after compressed air is fed, the stay wire is fed into the stay wire cavity at the tail end of the adjustable bend catheter.

In one possible implementation, the pressure of the compressed air is greater than or equal to 0.5Mpa.

In one possible implementation manner, the preset die is of a three-way valve structure, and the preset die comprises an air inlet, a conduit connection port and a wire outlet, wherein the diameters of the air inlet, the conduit connection port and the wire outlet are larger than or equal to the diameter of the adjustable bend conduit.

In one possible implementation, the conduit connection port and the pull wire outlet are on the same plane, and the angle between the air flow inlet and the conduit connection port is less than or equal to 45 °.

In a third aspect, the present application provides a method of securing an adjustable bend catheter pull wire, the method comprising:

threading the pull wire into a lumen within the circumference of the multi-lumen tube; wherein the stay wire is the stay wire of the first aspect, and the length of the multi-cavity tube is 4-6 mm;

and filling the gap between the stay wire and the cavity channel in the circumference of the multi-cavity tube with an adhesive, and welding the post-treated multi-cavity tube and the adjustable bending catheter into a whole.

In one possible implementation, the multi-lumen tube is welded to the adjustable bend conduit by fusion welding at a temperature of 200-220 ℃.

From the above, the present application provides a pull wire, a threading method and a fixing method for an adjustable bend catheter, wherein the pull wire is made of aromatic polyamide fiber, the pull wire is made of multi-strand twisted wire structure, and the diameter of the pull wire is 0.1-0.35 mm. Compared with a metal stay wire, the tensile strength and bending elongation of the aromatic polyamide fiber stay wire are the same as those of the metal stay wire, the fatigue resistance and flexibility of the aromatic polyamide fiber stay wire are superior to those of the metal stay wire, the bending force of the bending-adjustable catheter can be reduced by using the aromatic polyamide fiber stay wire, the bending flexibility of the bending-adjustable catheter is greatly enhanced, and the bending-adjustable requirements of the bending-adjustable catheter and the micro-catheter used in the intracardiac ultrasonic process are met; compared with other common high polymer polyester fibers, the aromatic polyamide fiber has the characteristics of high temperature resistance and stable chemical property, is convenient for fixing and welding the aromatic polyamide fiber stay wire on the adjustable bending catheter, can not deform due to high-temperature processing of the catheter, and can maintain the integrity.

According to the threading method of the adjustable bent catheter stay wire, the aromatic polyamide fiber stay wire which is not easy to penetrate into the stay wire cavity is penetrated into the cavity by using the die under the assistance of high-speed air flow; the method for fixing the stay wire of the adjustable bent catheter is different from the common stay wire and pull ring fixing of the adjustable bent catheter, wherein the stay wire and a multi-cavity tube are fixed together, and then the multi-cavity tube with the fixed stay wire and the adjustable bent tube body are welded together by using a die.

Drawings

In order to more clearly illustrate the technical solution of the present application, the drawings that are needed in the embodiments will be briefly described below, and it will be obvious to those skilled in the art that other drawings can be obtained from these drawings without inventive effort.

FIG. 1 is a schematic view of an adjustable bend conduit according to an embodiment of the present application;

FIG. 2 is a schematic illustration of threading an adjustable bend conduit pull wire according to an embodiment of the present application;

FIG. 3 is a schematic illustration of a pull wire fixation of an adjustable bend catheter according to an embodiment of the present application;

FIG. 4 is a schematic view of a multi-lumen tube according to an embodiment of the present application;

FIG. 5 is a schematic cross-sectional view of a multi-lumen tube according to an embodiment of the present application;

FIG. 6 is a schematic view of an interface of an adjustable bend conduit according to an embodiment of the present application;

FIG. 7 is a schematic diagram of a welding mold according to an embodiment of the present application;

fig. 8 is a diagram showing a bending effect of the bending-adjustable catheter according to the embodiment of the present application.

Illustration of:

1-a main lumen channel of a multi-lumen tube; 2-a multi-lumen tube pull wire lumen; 3-stay wire; 4-air flow inlet; 5-a catheter connection port; 6-a stay wire outlet; 7-adjustable bend conduit.

Detailed Description

In order to facilitate the technical solution of the application, some concepts related to the present application will be described below first.

As an interventional medical device, a medical adjustable bend catheter often needs to be subjected to bending control when in use. Bending control may be achieved by tightening and loosening the pull wires located in the distal bending sections of the respective tubes. The wires may be arranged in pairs, one on each of the two radially opposite sides of the distal bending section, which may bend towards the wire-tightening side by tightening one of the wires and loosening the other.

Through single or many pre-buried stay wire cavities in the medical adjustable curved pipe wall, will stay wire one end is fixed at the pipe head end again, and the cavity other end stretches out from the pipe afterbody of passing to stay wire, then pulls and draws the curved function of realizing unidirectional or multidirectional accent. In order to ensure the strength of the stay wire and the convenience of fixing at the head end of the catheter and penetrating the stay wire into the stay wire cavity, the elongation of the stay wire is as small as possible when the stay wire is pulled, and single-strand or multi-strand metal wires are generally selected as the stay wire. However, for some microcatheter adjustable elbows, intracardiac ultrasound catheters, or other catheters that are more rigid in terms of bending performance during actual use, and require flexibility in terms of bending of the catheter, metal pull wires often fail to meet performance requirements. Because the metal wire has certain inherent rigidity, the metal wire is easy to rebound after being bent in the bending process of the bending-adjustable catheter, not only the flexibility of the catheter is reduced, but also the bending force of the bending adjustment of the catheter is increased, and the metal wire can scratch the catheter body during bending adjustment, so that the function of the catheter is seriously lost.

The length of the common adjustable bent catheter is more than 600mm, the size of the stay wire cavity is about 0.05mm larger than the diameter of the stay wire, and the use of the metal stay wire is convenient for penetrating the stay wire cavity due to certain hardness, so that the head end metal stay wire can be welded with the metal ring well and fixed. The high polymer polyester stay wire is softer, and the stay wire is difficult to penetrate into a tiny stay wire cavity, and the stay wire cavity is easily enlarged and even damaged by directly using a method of threading a needle and a lead wire. In addition, for some pipe body structures which are not suitable for pull rings to be used as fixing, the macromolecule pull wire and the head end are difficult to fix, and the conventional fusion welding method can lead to the falling of the pull wire when the pull wire is bent due to overlarge difference of melting points of resin of the pull wire and the fixed pull wire at the head end of the catheter or deformation when the pull wire is fused; other knots and extrusion are fixed, when the catheter is bent, the knots extrude resin to cause the inner wall of the pipe body to be extruded, the space of the inner layer is reduced, the passing performance of the pipe body is affected, and in addition, the stay wire with high probability falls off.

Based on the above, the application provides a stay wire for an adjustable bending catheter, a threading method and a fixing method, which solve the problems that the flexibility of the catheter is reduced by rebound after bending of a metal wire in the bending process of the adjustable bending catheter, and even the catheter is damaged. The adjustable bending catheter is obtained by threading and fixing the aromatic polyamide fiber on the catheter body of the adjustable bending catheter, as shown in fig. 1, a part A is a multi-cavity catheter, a part B, C, D is an adjustable bending catheter main body part, a preset die is sleeved at a position B in the threading process, the preset die is taken down after the threading is finished, a part A and a part B are welded, and then the end part after the threading is finished is fixed at the part A.

Some of the terms used in connection with the present application are defined as follows:

Aromatic polyamide fiber, abbreviated as aramid fiber, and synthetic fiber spun from linear polyamide containing aromatic ring. Is classified into wholly aromatic polyamide fibers and aromatic ring-containing aliphatic polyamide fibers. The main varieties are poly-paraphenylene terephthalamide fibers and poly-m-phenylene isophthalamide fibers.

D in 150-250D/72-144F represents the thickness of the stay wire, and F represents the number of stay wires.

The AB glue is epoxy resin glue.

PEBAX is a trade name identified for its blocked polyether amide resin product, specifically polyether block polyamide. pebax5533 and "55" or "72" in pebax7233 indicate shore hardness, and "33" indicates that the melting point thereof is 174 ℃.

PA chemical name polyamide is Nylon (Nylon).

The UV adhesive is also called photosensitive adhesive and ultraviolet curing adhesive, is an adhesive which can be cured by ultraviolet light irradiation, and can be used as an adhesive and also can be used as sizing materials of paint, coating, printing ink and the like.

FEP, known as Fluorinated ethylene propylene, translates into fluorinated ethylene propylene copolymers (perfluoroethylene propylene copolymers).

ICE catheters are intracardiac ultrasound catheters.

PTFE is polytetrafluoroethylene.

In a first aspect, the application provides a stay wire for an adjustable bend catheter, wherein the stay wire is made of a polyester polymer material, specifically an aromatic polyamide fiber, abbreviated as aramid fiber. Because the fibers diverge in a natural state, the stay wire is affected to penetrate into the stay wire cavity and fix the head end, and the assembly of a subsequent catheter is affected; the stay wire for the adjustable bend conduit is a multi-strand twisted wire, so that the stay wire is in a multi-strand soft state and cannot diverge, and in some embodiments, the diameter of the stay wire is 0.1-0.35 mm.

Wherein, the dimension of the stay wire can be selected by referring to the dimension of the stay wire cavity of the adjustable bending catheter, and the diameter of the stay wire is required to be 0.05mm or more smaller than that of the stay wire cavity; specifically, the size of the stay wire cavity is designed according to the wall thickness of the catheter tube body, the maximum size is limited by specific specifications of products, and the diameter size of the general stay wire cavity is between 0.25 and 0.45 mm.

The number and the number of the twisted wires are not particularly required, and only a plurality of strands of soft wires are required to be ensured to be not diverged; in some embodiments the draw wire has a twist number of 4 to 8 per inch without distinguishing between S-twist and Z-twist. Each single-stranded part of the multi-stranded twisted wire is composed of long fiber tows, the dimension specification of the long fiber tows is 150-250D/72-144F, namely, the weight of each 9000m is 150-250 g, and the number of each fiber is 72-144.

In a second aspect, the present application further provides a threading method for a pull wire of an adjustable bend catheter, wherein the pull wire of the first aspect is threaded into a pull wire cavity reserved in the adjustable bend catheter by using an air-assisted manner.

As shown in fig. 2, the threading method includes:

Fixing a preset die at the head end of the adjustable bent conduit, and feeding compressed air through an air inlet of the preset die;

after compressed air is fed, the stay wire is fed into the stay wire cavity at the tail end of the adjustable bend catheter.

The die comprises an air inlet, a conduit connection port and a stay wire outlet, wherein the air inlet, the conduit connection port and the stay wire outlet are larger than or equal to the diameter of the adjustable bent conduit.

The method comprises the steps of fixing a preset mould at the head end of an adjustable bent catheter, blowing compressed air into the mould to enable negative pressure to be formed in a stay wire cavity of the adjustable bent catheter, then sending a stay wire into a stay wire cavity of the tail end of the adjustable bent catheter, taking the stay wire out by the action of air flow, and finishing the stay wire. In some embodiments, the air stream uses compressed air at a pressure greater than 0.5Mpa.

The air inlet of the preset die is required to be tightly coated at the head end of the adjustable bent catheter, so that no serious air leakage at the joint is ensured.

In a third aspect, the present application further provides a method for fixing an adjustable bend catheter pullwire, as shown in fig. 3, where the fixing method includes:

penetrating a pull wire into a lumen within the circumference of the multi-lumen tube; wherein the stay wire is the stay wire of the first aspect, and the length of the multi-cavity tube is 4-6 mm;

And filling the gap between the stay wire and the cavity channel in the circumference of the multi-cavity tube with an adhesive, and welding the post-treated multi-cavity tube and the adjustable bending catheter into a whole. In some embodiments, the adhesive may be a UV glue, a quick-drying glue, an AB (epoxy) glue.

As shown in fig. 4 and 5, the middle of the multi-cavity tube structure is a main cavity channel, the main cavity channel can be round or abnormal, and one or more cavities are arranged in the circumference of the tube wall of the multi-cavity tube; in order to ensure that the fixing condition of the stay wire is accurately known, the multi-cavity tube in some embodiments can be a transparent tube body made of pebax or PA, and the ultraviolet lamp can irradiate the adhesive in the multi-cavity tube by setting the multi-cavity tube to be made of transparent materials. The hardness of the multi-cavity tube is required to be greater than that of the part of the adjustable bent catheter welded with the multi-cavity tube so that the multi-cavity tube and the stay wire are better integrated. Wherein, the difference of the melting points of the two materials of the adjustable bent catheter welding position and the multi-cavity tube is less than 50 ℃, so that the welding is smoother, and the poor welding is avoided. The outer diameter of the multi-cavity tube is the same as the tube body of the bending-adjustable catheter main body, and the length of the multi-cavity tube is about 4-6 mm.

Through penetrating the multi-cavity tube circumference inner cavity way with acting as go-between, use low viscosity, high temperature resistant UV to glue and fill the gap, use ultraviolet lamp to shine again, make act as go-between and multi-cavity tube form an organic wholely under the effect of UV gluey. Because UV glues can solidify fast under ultraviolet lamp shines, and uses the UV to glue and be stronger to the connection force of acting as go-between and multi-chamber pipe, can satisfy the requirement of adjusting the bending of adjustable curved pipe (be greater than 40N), and use glue to fix can not make the multi-chamber pipe warp, also can not lead to the fact the fixed inefficacy of acting as go-between because of high temperature welding. Wherein, the ultraviolet lamp curing UV glue must be carried out in the camera bellows, prevents that other visible light from producing the influence to the solidification effect.

After the stay wire of the adjustable bend catheter is fixed with the multi-cavity tube, the multi-cavity tube is fixed with the adjustable bend catheter. The welding mode of the multi-cavity tube after fixing the stay wire and the adjustable bent catheter tube body is fusion welding, a welding instrument capable of blowing high-temperature gas is used, the two tube bodies are spliced together by using a welding die, an FEP (fluorinated ethylene propylene copolymer) heat shrinkage tube is sleeved, the two tube bodies are welded together after being melted by high-temperature hot air, the welding temperature is 200-220 ℃, and the welding time is dependent on materials and is generally not more than 2 minutes.

To prevent the weld material from collapsing under heat, a welding die may be used to support the multi-lumen tube and the adjustable bend catheter tube. The welding mould is a round or abnormal integrated mould, and the welding mould is required to be respectively matched with the head end of the adjustable bent catheter and the multi-cavity tube. The die is made of stainless steel or other hard metals, and the surface of the die is subjected to PTFE coating treatment so as to prevent the materials from adhering to the die during welding.

Examples

The para-position aromatic polyamide fiber is used as a stay wire, a double-stranded twisted wire with the twist of 75 and the diameter of 0.25-0.27 mm and single-stranded fiber bundle specification of 200D/100F and the breaking force of 50-60N are selected, and a four-way adjustable bent pipe is manufactured, the section of the pipe body is shown in figure 6, the length of the four-way adjustable bent pipe is 950mm, and the size of a stay wire cavity is 0.33mm.

In this embodiment, the method of threading the pull wire into the pull wire lumen of the adjustable bend catheter is as follows: as shown in FIG. 6, the cross section of the tube body of the four-way adjustable bent catheter in the embodiment is 950mm in length, and the size of the stay wire cavity is 0.33mm. As shown in fig. 2, the Y-shaped die is sleeved at the head end of the tube body, 0.7mMpa of compressed gas is introduced at the air inlet, four aramid fiber stay wires are respectively arranged at the tail end of the stay wire cavity of the adjustable bent catheter, and the stay wires are ejected from the outlet of the die stay wires after being sucked into the cavity by negative pressure formed by the gas.

The fixing method of the stay wire and the multi-cavity tube comprises the following steps: as shown in fig. 4 and 5, the main cavity is a cross-shaped structure, in this embodiment, the main cavity is fixed with the stay wire, the length of the multi-cavity tube is 5mm, the stay wire is first inserted into the stay wire cavity of the multi-cavity tube, the high temperature resistant and low viscosity UV glue is filled into the stay wire cavity by using an injector and other objects, the multi-cavity tube after glue injection is then placed into a camera bellows, and irradiated by an ultraviolet lamp, after 1-2 min, the multi-cavity tube is taken out, and the stay wire and the tube body on one side of the multi-cavity tube are trimmed and leveled. As shown in figure 7, the die is a die for welding a multi-cavity tube and an adjustable bent tube body, the die is made of stainless steel sprayed with a PTFE coating, two ends of the die are respectively adapted to a straight-shaped cavity channel of the adjustable bent tube and a cross-shaped inner cavity of the multi-cavity tube, the end of the adjustable bent tube is made of pebax5533, the multi-cavity tube is made of transparent pebax7233, the two parts are tightly connected together through the die, an FEP heat-shrinkable tube is sleeved on the outer layer, the welding is performed by a hot air welding machine at 220 ℃, and the welding time is 40-60 seconds.

The performance of the adjustable bend catheter made of the aramid fiber pull wire (abbreviated as aramid pull wire) and the metal pull wire used in the examples is analyzed as follows:

Two different adjustable bent guide pipes with diameters of 0.25 plus or minus 0.01mm are respectively made for the stainless steel stay wire and the aramid fiber stay wire.

1. Comparison of breaking force and bending adjustment of pull wire

The bending analysis is carried out on the bending-adjustable guide pipe of the stay wire made of different materials, the bending-adjustable guide pipe is mainly analyzed on the two aspects of bending-adjustable times and the elongation of the stay wire after bending adjustment, the fatigue resistance of the stay wire and the use function of the guide pipe after the handle is assembled are mainly tested, and the specific analysis is shown in the table 1.

TABLE 1

The data in table 1 indicate: in the aspect of breaking force, the metal stay wire and the aramid fiber stay wire can meet the use requirement of an ICE (intracardiac ultrasound) catheter, and the breaking force of the aramid fiber stay wire is slightly high but is not very different from that of the metal stay wire.

In the aspect of adjustable bending times, the bending times of the adjustable bending guide pipe in the actual process can not be more than 50 times, the metal stay wire and the aramid fiber stay wire in the experiment are subjected to 50 times of bending adjustment, and the bending adjustment function of the guide pipe is not damaged greatly.

Elongation of the stay wire after 50 times of bending adjustment: this property affects mainly the accuracy of the handle during actual use of the adjustable bend catheter, wherein lower elongation is more accurate and lower than 5% can meet the actual requirements.

2. Bending property of pipe body

The bending performance of the tube body of the adjustable bent catheter is particularly the flexibility of the tube body, and after the adjustable bent catheter enters the human blood vessel, the softer the adjustable bent catheter, the less the damage to the human blood vessel is caused because the blood vessel is in a non-straight state.

The simulation test method is that the bending section of the ICE catheter assembled by the stay wires of different materials is bent by 90 degrees and 180 degrees under the action of external force, and the minimum force is required, and the specific test data are shown in the table 2:

TABLE 2

Bending property	Metal bending force N	Aramid bending force N
			Bending by 90 DEG	0.32	0.21
Bending 180 DEG	0.88	0.41

The data show that the force used in bending the aramid pull wire at 90 degrees and 180 degrees is smaller, so the performance of the aramid pull wire is better than that of the metal pull wire.

3. Bending property

The bending force is a key parameter of the ICE catheter, and the magnitude of the bending force determines the difficulty of realizing the function of the catheter in actual use.

The testing method comprises the following steps: the force values required to pull the pull wire to bend the adjustable bend catheter 90 and 180 are shown in table 3.

TABLE 3 Table 3

Bending property	Metal bending force N	Aramid bending force N
			Bending by 90 DEG	4.03	3.92
Bending 180 DEG	7.44	6.35

The data in the table above indicate: the bending force of the aramid fiber stay wire is smaller than that of the metal stay wire, namely, the aramid fiber stay wire can realize the bending adjusting function of the ICE catheter more easily under the same tension value.

In conclusion, the aramid pull wire is more suitable for manufacturing ICE catheters. The experiment finally determines that the aramid fiber material is the optimal choice, the aramid fiber stay wire not only meets the requirements on breaking force and breaking elongation, but also has excellent high temperature resistance and fatigue resistance, the aramid fiber is cheap, and the manufacturing cost of the catheter is low. The aramid fiber stay wire selected in actual use is a multi-strand stay wire, and the multi-strand wire has better flexibility. Fig. 8 (a), fig. 8 (b) and fig. 8 (c) are respectively effect diagrams of the bending section of the bending-adjustable catheter in a straight state, bending by 90 degrees and bending by 180 degrees.

The performance of the adjustable bend conduit made of the aramid fiber pull wire (abbreviated as aramid pull wire) and the nylon pull wire used in the examples is analyzed as follows:

the specific experimental data are shown in table 4:

TABLE 4 Table 4

After the material and the mode of the stay wire are determined, the size of the stay wire is selected mainly by referring to two points: the size of the pull wire cavity and the breaking strength of the pull wire. Since the ICE catheter wall thickness is as small as possible, the wire lumen is also selected to be as small as possible; the size of the pull-wire breaking force meeting the requirement is that the wire diameter is more than or equal to 0.25mm. By considering the above factors in combination, the inner diameter of the stay wire cavity is selected to be 0.3mm, and the size of the stay wire is selected to be 0.27mm. (because the polymer multi-strand stay wire is fluffy, the test size is 0.25-0.30 mm, and the average size is 0.27 mm), and the breaking force of the stay wire is measured to be 48N.

The experiment finally determines that the aramid fiber material is the optimal choice, the aramid fiber stay wire not only meets the requirements on breaking force and breaking elongation, but also has excellent high temperature resistance and fatigue resistance, and the aramid fiber is cheap, and the manufacturing cost of the adjustable bending catheter is low. The aramid fiber stay wire selected in actual use is a multi-strand stay wire, and the multi-strand wire has better flexibility.

From the above embodiments, the present application provides a pull wire, a threading method and a fixing method for an adjustable bend catheter, wherein the pull wire is made of an aromatic polyamide fiber, the pull wire is made of a multi-strand twisted structure, the twisting number of the pull wire is 40-80 per inch, the diameter of the pull wire is 0.1-0.35 mm, and the breaking force of the pull wire is greater than or equal to 40N. The bending-adjustable conduit wire is twisted by aromatic polyamide fiber (aramid fiber), compared with a metal wire, the tensile strength and bending-adjustable elongation of the aromatic polyamide fiber wire are the same as those of the metal wire, the fatigue resistance and flexibility of the aromatic polyamide fiber wire are superior to those of the metal wire, the bending-adjustable force of the bending-adjustable conduit can be reduced by using the aromatic polyamide fiber wire, the bending flexibility of the bending-adjustable conduit is greatly enhanced, and the bending-adjustable requirements of the bending-adjustable conduit, the micro-conduit bending-adjustable conduit and the like used in the intracardiac ultrasonic process are met. Compared with other common high polymer polyester fibers, the aromatic polyamide fiber has the characteristics of high temperature resistance and stable chemical property, is convenient for fixing and welding the aromatic polyamide fiber stay wire on the adjustable bending catheter, can not deform due to high-temperature processing of the adjustable bending catheter, and can keep the integrity.

According to the threading method of the adjustable bent catheter stay wire, provided by the application, the aramid fiber stay wire which is not easy to penetrate into the stay wire cavity is penetrated into the cavity by using the die under the assistance of high-speed air flow; the method for fixing the stay wire of the adjustable bent catheter is different from the common stay wire and pull ring fixing of the adjustable bent catheter, wherein the stay wire and a multi-cavity tube are fixed together, and then the multi-cavity tube with the fixed stay wire and the adjustable bent tube body are welded together by using a die.

According to the threading method of the adjustable bent catheter stay wire, provided by the application, the aramid fiber stay wire which is not easy to penetrate into the stay wire cavity is penetrated into the cavity by using the die under the assistance of high-speed air flow; the method for fixing the stay wire of the adjustable bent catheter is different from the common stay wire and pull ring fixing of the adjustable bent catheter, wherein the stay wire and a multi-cavity tube are fixed together, and then the multi-cavity tube with the fixed stay wire and the adjustable bent tube body are welded together by using a die.

Claims (10)

1. The stay wire for the adjustable bend catheter is characterized in that the stay wire is made of aromatic polyamide fibers and is of a multi-strand twisting structure, and the diameter of the stay wire is 0.1-0.35 mm.

2. The pull wire of claim 1, wherein a difference between a diameter of a pull wire lumen of the adjustable bend catheter and a diameter of the pull wire is greater than or equal to 0.05mm.

3. The pull cord according to claim 1, wherein each single strand portion of the pull cord is a bundle of long fibers, the number of long fibers per bundle is 72-144, and the number of turns of the pull cord is 4-8 per inch.

4. A threading method of a pull wire of an adjustable bend catheter, characterized in that the pull wire of any one of claims 1-3 is threaded into a pull wire cavity reserved in the adjustable bend catheter by using an air flow auxiliary mode.

5. The threading method according to claim 4, characterized in that the threading method comprises:

Fixing a preset die at the head end of the adjustable bent conduit, and feeding compressed air through an air inlet of the preset die;

after compressed air is fed, the stay wire is fed into the stay wire cavity at the tail end of the adjustable bend catheter.

6. The threading method according to claim 5, wherein the pressure of the compressed air is greater than or equal to 0.5Mpa.

7. The threading method of claim 5, wherein the preset die is of a three-way valve structure and comprises an air inlet, a conduit connection port and a pull wire outlet, and the diameters of the air inlet, the conduit connection port and the pull wire outlet are larger than or equal to the diameter of the adjustable bend conduit.

8. The threading method of claim 7 wherein the conduit connection port is coplanar with the pull wire outlet and the air flow inlet is at an angle of less than or equal to 45 ° to the conduit connection port.

9. A method of securing an adjustable bend catheter pull wire, the method comprising:

threading the pull wire into a lumen within the circumference of the multi-lumen tube; wherein the stay wire is the stay wire according to any one of claims 1 to 3, and the length of the multi-cavity tube is 4 to 6mm;

and filling the gap between the stay wire and the cavity channel in the circumference of the multi-cavity tube with an adhesive, and welding the post-treated multi-cavity tube and the adjustable bending catheter into a whole.

10. The method of fixing according to claim 9, wherein the multi-lumen tube and the flexible catheter are welded by fusion welding at a temperature of 200-220 ℃.