A varicose vein ablation catheter and its catheter tip

Abstract

The present invention relates to the technical field of surgical instruments, and particularly relates to a varicose vein ablation catheter and its catheter head. The catheter head includes a microwave needle, an insulating sleeve, a metal sleeve, and an outer sleeve coaxially connected in sequence from the head end to the tail end; a cable is coaxially arranged inside the outer sleeve; the front end of the inner conductor of the cable passes through the metal sleeve, the insulating sleeve, and is connected to the tail end of the microwave needle; the outer conductor of the cable is connected to the metal sleeve; the axial length of the exposed part at the head end of the microwave needle is L1, the axial length of the exposed part at the head end of the insulating sleeve is L2, and the axial length of the exposed part at the head end of the metal sleeve is L3; L1 = L3 ± 0.4 mm; L2 ≥ 2 mm; L1 + L2 + L3 = n*(1 / 5 - 3 / 10)λ. By making the length of the catheter head approximate to a quarter wavelength, the present invention enables a relatively high ablation temperature, which can avoid the situation where the temperature fails to meet the requirements due to a low microwave power, thereby avoiding the phenomenon that the blood vessels cannot be closed.

Description

Technical Field

[0001] The present invention relates to the technical field of surgical instruments, and particularly to a varicose vein ablation catheter and its tip. Background Art

[0002] Clinically, the varicose vein ablation catheter mainly cooperates with a microwave ablation system to achieve the ablation treatment of great saphenous varicose veins in the lower extremities. Its working principle is that the microwave ablation system generates microwave energy, and the energy is emitted through the varicose vein ablation catheter and acts on the blood vessel wall. The microwave energy is converted into heat energy by the rapid rotation and mutual friction of water molecules in the tissue to coagulate the blood vessel wall until the blood vessel closes and finally fibrosis occurs.

[0003] When using such a varicose vein ablation catheter made based on the microwave ablation principle, it is necessary to ablate the vein section by section. Specifically, in the way of retreating ablation, after closing the distal end of the vein, the catheter is withdrawn a certain distance proximally, so that the tip moves to the area where the blood vessel is not closed, and then ablation is carried out until the entire blood vessel is closed.

[0004] For example, Chinese Patent with publication number CN111617385A discloses a temperature-controlled varicose vein electrode with a cold circulation. However, when using such a product, the operator needs to perform multiple retreating ablations, and the efficiency is not high.

[0005] Technicians have found through subsequent research that the length of blood vessel closure during a single ablation directly affects the surgical efficiency. If the length of blood vessel closure during a single ablation is short, then the operator needs to perform multiple operations to completely close the blood vessel. If the length of blood vessel closure during a single ablation is long, then the number of operations by the operator will be significantly reduced, thus improving the efficiency.

[0006] However, as the length of a single ablation increases, the energy field distribution is uneven, and there will be some areas that cannot be completely closed, resulting in poor treatment effects for varicose veins. Summary of the Invention

[0007] To solve the problem that some blood vessels cannot be closed during ablation in the prior art, the purpose of the present invention is to provide a varicose vein ablation catheter and its tip.

[0008] The technical solution provided by the present invention is as follows:

[0009] In a first aspect, a tip of a varicose vein ablation catheter includes a microwave needle tip, an insulating sleeve, a metal sleeve, and an outer sleeve coaxially connected in sequence from the head end to the tail end;

[0010] A cable is coaxially arranged inside the outer sleeve; the front end of the inner conductor of the cable passes through the metal sleeve, the insulating sleeve, and is connected to the tail end of the microwave needle tip; the outer conductor of the cable is connected to the metal sleeve;

[0011] The cable is used to connect a microwave generating device with a microwave wavelength of λ;

[0012] The head and tail ends of the microwave needle are located inside the insulating sleeve, the tail end of the insulating sleeve is located inside the metal sleeve, and the tail end of the metal sleeve is located inside the outer sleeve;

[0013] The axial length of the exposed part at the head end of the microwave needle is L1, the axial length of the exposed part at the head end of the insulating sleeve is L2, and the axial length of the exposed part at the head end of the metal sleeve is L3;

[0014] Wherein: L1 = L3 ± 0.4 mm; L2 ≥ 2 mm; L1 + L2 + L3 = n * (1 / 5 - 3 / 10)λ, and n is a positive integer.

[0015] As an optional technical solution in the first aspect, L1 is equal to L3, and L1 + L2 + L3 = n * λ / 4.

[0016] As an optional technical solution in the first aspect, L2 is 2 - 3 mm.

[0017] As an optional technical solution in the first aspect, the tail end of the metal sleeve extends towards the tail end of the catheter tube relative to the tail end of the insulating sleeve, and the extension length is L5, wherein L5 ≥ 3 mm;

[0018] The outer conductor of the cable is connected to the tail end of the metal sleeve and the tail end of the insulating sleeve, and the insulating sleeve, the metal sleeve, and the cable form a closed cavity;

[0019] A thermocouple wire is arranged inside the outer sleeve, and the head end of the thermocouple wire extends into the closed cavity and is connected to the temperature-measuring thermocouple inside the closed cavity.

[0020] As an optional technical solution in the first aspect, the tail end of the insulating sleeve extends towards the tail end of the catheter tube relative to the tail end of the microwave needle, and the extension length is L6, wherein L6 ≥ 3 mm;

[0021] The tail end of the microwave needle and the head end of the metal sleeve are staggeredly arranged, and the two are separated by the insulating sleeve;

[0022] Taking the plane where the head end of the metal sleeve is located as the reference plane, the tail end of the microwave needle extends towards the tail end of the catheter tube relative to this reference plane, and the extension length is L4, wherein L4 = (3 / 10 - 1)L3.

[0023] Optionally, the front end of the inner conductor is welded to the end face of the tail end of the microwave needle; the axial length of the inner conductor exposed outside the cable is not greater than L6.

[0024] As an optional technical solution in the first aspect, the outer sides of the microwave needle, the insulating sleeve, and the metal sleeve are coated with Teflon.

[0025] In a second aspect, a varicose vein ablation catheter includes the catheter tip of the varicose vein ablation catheter in the first aspect; it further includes a handle, and this handle is provided with a temperature measurement connector and a microwave connector; an outer catheter is connected to the housing of the handle; a thermocouple wire is connected to the temperature measurement connector; a cable is connected to the microwave connector.

[0026] As an optional technical solution in the second aspect, it further includes a cooling water pipe, and this cooling water pipe is sleeved outside the cable and is located inside the outer catheter; a water isolation layer is provided on the outside of the outer conductor;

[0027] The cooling water pipe is connected to the tail end of the metal sleeve; a through hole is provided in a section of the cooling water pipe close to the metal sleeve;

[0028] A water inlet flow channel is formed between the cooling water pipe and the cable, and a water outlet flow channel is formed between the cooling water pipe and the outer catheter; a water isolation ring is provided at one end of the water inlet flow channel close to the metal sleeve;

[0029] The water inlet flow channel and the water outlet flow channel are communicated through the through hole;

[0030] The handle is further provided with a water inlet pipe and a water outlet pipe, wherein the water inlet flow channel is communicated with the water inlet pipe, and the water outlet flow channel is communicated with the water outlet pipe.

[0031] As an optional technical solution in the second aspect, a plurality of groups of annular scales are provided on the outer side surface of the outer catheter; this annular scale is used to indicate the length of the catheter entering and / or being pulled out of the vein.

[0032] Adopting the technical solution provided by the present invention, compared with the prior art, it has the following beneficial effects:

[0033] By making the length of the catheter tip approximate to a quarter wavelength, the ablation temperature is relatively high in the present invention, which can avoid the phenomenon that the temperature cannot reach the required value due to the low microwave power, and thus can avoid the phenomenon that the blood vessel cannot be closed.

[0034] In addition, the temperature measurement thermocouple placed in the closed cavity formed by the insulating sleeve, the metal sleeve and the cable will not be too close to the microwave needle head and the insulating sleeve, so as to avoid the alternating magnetic field generated by the microwave slot antenna entering the measurement circuit of the temperature measurement thermocouple in the form of electromagnetic induction, ensuring that no interference current is generated in the measurement circuit of the temperature measurement thermocouple and improving the measurement accuracy. The metal sleeve can also play an electromagnetic shielding role on the temperature measurement thermocouple and can also avoid the generation of interference current by the alternating electromagnetic field in the measurement circuit of the temperature measurement thermocouple.

[0035] In addition, by staggering the head and tail ends of the microwave needle with the front end of the metal sleeve, when the head of the ablation catheter is subjected to a radial force, since the microwave needle and the metal sleeve are made of metal and have high strength, the head and tail ends of the microwave needle will provide a reaction force in the opposite direction. This reaction force can prevent the connection between the insulating sleeve and the microwave needle and the metal sleeve from being subjected to lateral and tensile forces from different directions, thereby avoiding the problem of connection failure at this connection and also preventing bending. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Schematic diagram of the head of a varicose vein ablation catheter in an embodiment of the present application;

[0037] Figure 2 Schematic diagram of a varicose vein ablation catheter in an embodiment of the present application;

[0038] Figure 3 Schematic diagram of the force when the head and tail ends of the microwave needle are not staggered with the head end of the metal sleeve;

[0039] Figure 4 Schematic diagram of the cracking position when the head and tail ends of the microwave needle are not staggered with the head end of the metal sleeve;

[0040] Figure 5 Schematic diagram of the bending position when the head and tail ends of the microwave needle are not staggered with the head end of the metal sleeve.

[0041] Description of the reference numerals in the schematic diagram:

[0042] Microwave needle 101;

[0043] Insulating sleeve 102;

[0044] Metal sleeve 103;

[0045] Outer sleeve 104;

[0046] Closed cavity 105;

[0047] Temperature-measuring thermocouple 106;

[0048] Thermocouple wire 107;

[0049] Outer conductor 108;

[0050] Inner conductor 109;

[0051] Head and tail ends of the microwave needle 110;

[0052] Circular scale 111;

[0053] Water-blocking ring 112;

[0054] Cooling water pipe 201;

[0055] Through hole 202;

[0056] Inlet flow channel 203;

[0057] Outlet flow channel 204;

[0058] Shell 301;

[0059] Inlet pipe 302;

[0060] Outlet pipe 303;

[0061] Temperature measurement joint 304;

[0062] Microwave joint 305. Specific implementation mode

[0063] To further understand the content of the present invention, the present invention will be described in detail in combination with the accompanying drawings and embodiments.

[0064] The structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those who are familiar with this technology to understand and read, and are not used to limit the limiting conditions under which the present invention can be implemented. Therefore, they do not have technical essence. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope that can be covered by the technical content disclosed in the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle", etc. cited in this specification are only for the convenience of narration and are not used to limit the scope that can be implemented. The change or adjustment of their relative relationship, without substantial change in the technical content, should also be regarded as the scope that the present invention can be implemented.

[0065] The present invention provides a catheter tip for varicose vein ablation, as Figure 1 shown, which includes a microwave needle head 101, an insulating sleeve 102, a metal sleeve 103, and an outer sleeve 104 that are coaxially connected in sequence from the head end to the tail end. Optionally, they are bonded by high-temperature glue.

[0066] The end face of the microwave needle head 101 is a smooth curved surface, in the shape of a hemisphere. When it is inserted into a blood vessel, the smooth curved surface enables the microwave needle head 101 to easily penetrate through the blood vessel. If the end of the microwave needle head 101 is sharp, the catheter is likely to get stuck in the blood vessel, resulting in poor penetration.

[0067] A cable is coaxially arranged inside the outer sleeve 104. The outer sleeve 104 can protect the cable, and the outer sleeve 104 and the cable arranged inside the outer sleeve 104 can form a semi-rigid catheter. The semi-rigid catheter can bend according to the shape of the blood vessel, so that the ablation catheter proposed by the present invention can be applicable to the treatment of varicose veins.

[0068] The cable includes an inner conductor 109, an insulating layer, and an outer conductor 108 from the inside to the outside. The inner conductor 109 is made of silver-plated copper alloy material, which can effectively reduce conductor attenuation and improve power capacity. The insulating layer can be made of low-density PTFE material, which can improve the microwave transmission efficiency and reduce dielectric attenuation. The outer conductor 108 is a 100% shielded seamless alloy of tin, copper, and zinc, with a bending radius of up to 1.6 mm, no obvious cracks when bent, and good weldability. A water-repellent layer can be formed on the surface of the outer conductor 108 by electroless plating of tetrafluoroethylene, which can effectively isolate the outer conductor from water contact and improve the antioxidant performance of the ablation catheter.

[0069] The front end of the inner conductor passes through the metal sleeve 103, the insulating sleeve 102, and is connected to the head and tail end 110 of the microwave needle. The outer conductor 108 is electrically connected to the metal sleeve 103. When the cable is connected to the microwave generating device, it should be noted that the cable can be directly connected to the microwave generating device, or it can be connected to the microwave generating device through other adapter cables. The microwave generating device provides microwaves with a wavelength of λ.

[0070] The present invention is based on the application principle of a microwave slot antenna. Among them, the microwave needle 101 serves as the positive electrode, the insulating sleeve 102 serves as the slot, the metal sleeve 103 is grounded, and the microwave needle 101, the insulating sleeve 102, and the metal sleeve 103 form a microwave slot antenna. The slot has the same directivity as the microwave radiation antenna. According to the analysis of the magnetic field pattern of the slot antenna, at the slot, that is, at the insulating sleeve 102, the energy field is the strongest and the temperature is the highest.

[0071] For the material of the insulating sleeve 102, as an alternative solution, the insulating sleeve 102 can be a tetrafluoro lining sleeve.

[0072] The head and tail end 110 of the microwave needle is located inside the insulating sleeve 102, the tail end of the insulating sleeve 102 is located inside the metal sleeve 103, and the tail end of the metal sleeve 103 is located inside the outer sleeve 104. Among them, the axial length of the exposed part of the head end of the microwave needle is L1, the axial length of the exposed part of the head end of the insulating sleeve is L2, and the axial length of the exposed part of the head end of the metal sleeve is L3.

[0073] Since the microwave wavelength is determined, if the axial length of the exposed part of the head end of the microwave needle is excessively increased, the microwave energy will decrease at this time. Therefore, in order to increase the ablation length, usually the length of the exposed part of the microwave needle is locally increased. However, in fact, the energy of the microwave in a certain area involves many factors, and simply controlling the length cannot effectively avoid the situation where the blood vessels in some areas cannot be closed.

[0074] One type of product in the prior art has a length of the exposed part of the microwave needle significantly shorter than that of the metal ferrule, and the length of tissue ablation per single time is short, so multiple operations are required. Another type has a length of the exposed part of the microwave needle significantly longer than that of the metal ferrule. Although the ablation length per single time is increased in this case, there is an unclosed area. However, even if the length of the exposed part of the microwave needle is made approximately equal to that of the metal ferrule, the situation where there are unclosed points in some areas still cannot be solved.

[0075] In this solution, let L1 = L3 ± 0.4 mm, that is, the present invention does not significantly increase the length of the exposed part of the microwave needle 101, but makes the axial length of the exposed part at the head end of the microwave needle approximately equal to the axial length of the exposed part at the head end of the metal sleeve, so as to form a relatively symmetrical magnetic field. At the same time, let L1 + L2 + L3 = n*(1 / 5 - 3 / 10)λ, where n is a positive integer, such as 1 or 2 or 3 or 4, etc. As an optional solution, L1 and L3 can be made equal, both being 6 mm.

[0076] Also in this solution, let L1 + L2 + L3 = n*λ / 4. When n = 1, the total length of L1 + L2 + L3 is one-fourth of the wavelength at this time. When it is at the wave crest, the microwave energy is the highest, which can avoid the phenomenon that the blood vessel cannot be closed due to the temperature not reaching the requirement.

[0077] The insulating sleeve 102 not only serves as a gap when forming the microwave slot antenna, but also is used to block the microwave needle 101 and the metal sleeve 103 to avoid short circuit. Therefore, the axial length of the exposed part at the head end of the insulating sleeve should not be too small. As an optional solution, L2 ≥ 2 mm, for example, L2 is 2 - 3 mm. At this time, if L1 = L3 = 6 mm, then the total length is 14 - 15 mm.

[0078] When using the ablation catheter to close the blood vessel, it is necessary to master the ablation temperature in real time. If the ablation temperature cannot be mastered, the blood vessel may not be closed due to low temperature, or may be carbonized due to high temperature. When the ablation temperature cannot be precisely controlled, ultrasonic real-time monitoring of the microwave closing process is often used, that is, the treatment effect is understood through the ultrasonic imaging during microwave ablation closing.

[0079] The present invention further realizes precise control of the ablation temperature by detecting the ablation temperature, keeps the ablation temperature within the set range, so as to ensure that the blood vessel can be completely closed and there is no need to use ultrasonic auxiliary detection.

[0080] Specifically, the tail end of the metal sleeve 103 extends towards the head end of the catheter tube relative to the tail end of the insulating sleeve 102, and the extension length is L5, where L5 ≥ 3 mm. The outer conductor 108 is connected to the tail end of the metal sleeve 103 and the tail end of the insulating sleeve 102, and the insulating sleeve 102, the metal sleeve 103, and the cable form a closed cavity 105.

[0081] A thermocouple wire 107 is arranged inside the outer sleeve 104, and the head end of the thermocouple wire 107 extends into the closed cavity 105 and is connected to the temperature-measuring thermocouple 106 inside the closed cavity 105.

[0082] Since the metal sleeve 103 has good thermal conductivity, the temperature of the metal sleeve 103 can be detected by using the temperature-measuring thermocouple 106, so that it is convenient for the operator to know the ablation temperature, and then control the microwave to adjust the ablation temperature.

[0083] Since the positions of the microwave needle head 101 and the insulating sleeve 102 are the main areas for the microwave slot antenna to emit an external electromagnetic field, especially the energy field at the insulating sleeve 102 is the strongest and the temperature is the highest. Therefore, if the temperature-measuring thermocouple 106 is placed at the microwave needle head 101 and the insulating sleeve 102, the alternating magnetic field generated by the microwave slot antenna will enter the measuring circuit of the temperature-measuring thermocouple 106 in the form of electromagnetic induction, thereby generating an interference current in the measuring circuit of the temperature-measuring thermocouple 106 and affecting the measurement accuracy. Therefore, in the present invention, the tail end of the metal sleeve 103 extends a distance of L5 in the direction of the head and tail ends of the catheter tube relative to the tail end of the insulating sleeve 102, and this length is not too small, so that the temperature-measuring thermocouple 106 placed in the closed cavity 105 formed by the insulating sleeve 102, the metal sleeve 103, and the cable is not too close to the microwave needle head 101 and the insulating sleeve 102, thereby avoiding the alternating magnetic field generated by the microwave slot antenna from entering the measuring circuit of the temperature-measuring thermocouple 106 in the form of electromagnetic induction, ensuring that no interference current is generated in the measuring circuit of the temperature-measuring thermocouple 106, and improving the measurement accuracy.

[0084] Moreover, the metal sleeve 103 is grounded. At this time, the metal sleeve 103 can play an electromagnetic shielding role for the temperature-measuring thermocouple 106, and can also avoid the alternating electromagnetic field from generating an interference current in the measuring circuit of the temperature-measuring thermocouple 106, thereby improving the accuracy of temperature measurement.

[0085] As Figure 3 shown, if the head and tail ends of the microwave needle do not stagger with the front end of the metal sleeve, then when the catheter head is subjected to a radial (or at an angle with the radial direction) acting force, the joints between the insulating sleeve 102 and the microwave needle head 101, and between the insulating sleeve 102 and the metal sleeve 103 will be subjected to Figure 3 the acting force in the direction shown by the arrow.

[0086] When the product is in use, the tube head will be under high-temperature conditions, and during the use of the product, the direction of this acting force will also change, that is, the tube head will bend back and forth in different directions. If the front and rear ends of the microwave needle of the product are not staggered with the front end of the metal sleeve, then the insulating sleeve 102 will be subjected to a lateral pulling force at the connection with the microwave needle 101 and the metal sleeve 103, and the direction of this lateral pulling force will also change during use, and connection failure may occur at the connection, that is, this connection breaks, as Figure 4 shown.

[0087] If the product has a structure where the front and rear ends of the microwave needle are not staggered with the front end of the metal sleeve, then even if the connection between the insulating sleeve 102 and the microwave needle 101 and the metal sleeve 103 does not break, due to the strength performance of the insulating sleeve 102, the tube head is prone to deformation, that is, bent into an arc shape, as Figure 5 shown. If the tube head of the ablation catheter is bent into an arc shape, then it will inevitably have an adverse impact on the directivity of the microwave slot antenna, that is, it will affect the actual use of the product.

[0088] In the present invention, the tail end of the insulating sleeve 102 extends towards the tail end of the catheter tube head relative to the front and rear ends 110 of the microwave needle, and the extension length is L6, where L6 ≥ 3 mm. This section of length should not be too small, so as to provide more space for the bonding of the outer conductor 108 and the insulating sleeve 102 with high-temperature glue, and also enable the inner conductor 109 to be as close as possible to the front and rear ends 110 of the microwave needle, while the inner conductor 109 is away from the metal sleeve 103 at the same time, avoiding short circuit due to contact between the inner conductor 109 and the metal sleeve 103.

[0089] The front and rear ends 110 of the microwave needle are staggered with the head end of the metal sleeve 103, and their overlapping position is as Figure 1 shown in the dashed box in. The two are separated by the insulating sleeve 102. Taking the plane where the head end of the metal sleeve 103 is located as the reference plane, the front and rear ends 110 of the microwave needle extend towards the tail end of the catheter tube head relative to this reference plane, and the extension length is L4, where L4 = (3 / 10 - 1)L3. The extension length L4 here should not be too small, as it cannot perform the function of providing support when it is too small. The extension length L4 should not be too large either, as it will reduce the connection length between the outer conductor 108 and the insulating sleeve 102, resulting in a decrease in their connection length, and it will also make the front and rear ends 110 of the microwave needle closer to the metal sleeve 103, increasing the risk of short circuit due to contact between the two.

[0090] By staggering the front and rear ends 110 of the microwave needle with the front end of the metal sleeve 103, when the head of the ablation catheter is subjected to a radial force, since the microwave needle and the metal sleeve are made of metal and have high strength, the front and rear ends 110 of the microwave needle will provide a reaction force in the opposite direction. This reaction force can prevent the insulating sleeve 102 from being subjected to lateral and tensile forces from different directions at the connection with the microwave needle 101 and the metal sleeve 103, thereby avoiding the problem of connection failure at this connection and also avoiding bending.

[0091] Since the present invention needs to form a closed cavity 105, the rear end of the metal sleeve 103 needs to be axially extended. Correspondingly, the front and rear ends 110 of the microwave needle are staggered with the front end of the metal sleeve 103, that is, the front and rear ends 110 of the microwave needle are also axially extended by a certain length. At this time, the microwave needle 101 can be closer to the inner conductor 109 of the coaxial cable, which is convenient for connecting the microwave needle 101 with the inner conductor 109 of the cable and reducing the product assembly difficulty.

[0092] In addition, since the insulating layer may recede due to rubbing during the assembly of the cable, the inner conductor 109 may come into contact with the metal sleeve 103 and cause a short circuit at this time. Therefore, the extended insulating sleeve 102 in this application can also cover a section of the cable to avoid the phenomenon of the inner conductor 109 coming into contact with the metal sleeve 103 and causing a short circuit, improving the insulation effect of the product.

[0093] For the connection method between the inner conductor 109 and the microwave needle 101, in one scheme, the front end of the inner conductor 109 is welded to the end face of the front and rear ends 110 of the microwave needle, and the axial length of the inner conductor 109 exposed from the cable is not greater than L6. This can avoid the inner conductor 109 coming into contact with the metal sleeve 103 and causing a short circuit, and also provide space for the fixed connection between the outer conductor 108 and the insulating sleeve 102.

[0094] Teflon is coated on the outer sides of the microwave needle 101, the insulating sleeve 102, and the metal sleeve 103.

[0095] The present invention also proposes a varicose vein ablation catheter, as Figure 2 shown, which includes the above-mentioned varicose vein ablation catheter head, and also includes a handle. This handle is provided with a temperature measurement connector 304 and a microwave connector 305. The outer sleeve 104 is connected to the housing 301 of the handle, for example, by bonding with a high-temperature adhesive.

[0096] The thermocouple wire 107 is connected to the temperature measurement connector 304. It should be noted that the thermocouple wire 107 can be directly connected to the temperature measurement connector 304, or can be connected to the temperature measurement connector 304 through a patch cord.

[0097] The cable is connected to the microwave connector 305. The cable can be directly connected to the microwave connector 305, or can be connected to the microwave connector 305 through a patch cord. The microwave connector 305 is connected to a microwave generating device.

[0098] Since this product uses a retraction ablation technique, a relatively high rod temperature poses a risk of damaging the patient's normal tissues and scalding the operator. As an alternative technical solution, it also includes a cooling water pipe 201. This cooling water pipe 201 is sleeved outside the cable and is located inside the outer sleeve 104. The cooling water pipe 201 is connected to the tail end of the metal sleeve 103, for example, by bonding with high-temperature glue.

[0099] A through hole 202 is provided at a section of the cooling water pipe 201 close to the metal sleeve 103. An inlet water flow channel 203 is formed between the cooling water pipe 201 and the cable, and an outlet water flow channel 204 is formed between the cooling water pipe 201 and the outer sleeve 104. The inlet water flow channel 203 and the outlet water flow channel 204 are connected through the through hole 202.

[0100] A water isolation ring 112 is provided at one end of the inlet water flow channel 203 close to the metal sleeve 103, so as to prevent the cooling water from contacting the metal sleeve 103.

[0101] The handle is also provided with a water inlet pipe 302 and a water outlet pipe 303. Among them, the inlet water flow channel 203 is communicated with the water inlet pipe 302, and the outlet water flow channel 204 is communicated with the water outlet pipe 303. The cooling water flows into the inlet water flow channel 203 from the water inlet pipe 302, then enters the outlet water flow channel 204 through the through hole 202, and finally flows out from the water outlet pipe 303, so as to carry out cooling.

[0102] As an alternative solution, multiple groups of annular scales 111 can be provided on the outer side surface of the outer sleeve 104. The length of the catheter entering and / or being pulled out of the vein can be indicated by the annular scales 111, so as to facilitate understanding the position of the ablation catheter and improve the convenience of using the product.

[0103] Ablation catheters with multiple groups of different axial lengths L1 of the exposed part of the head end of the microwave needle, axial length L2 of the exposed part of the head end of the insulating sleeve, and axial length L3 of the exposed part of the head end of the metal sleeve are selected for testing to detect the ablation range. The main machine used in this test is ECO-200G. The main machine has three treatment modes: ablation I, ablation II, and ablation III. The power setting range of the ablation I mode is 0 - 120W, and the power setting ranges of the ablation II and ablation III modes are 0 - 60W. Since the power setting range of the ablation III mode and the ablation I mode have an alarm function for the rod temperature default exceeding 45°C, the relevant tests above 65W were not carried out in this test.

[0104] The microwave powers are 45W, 50W, 55W, and 60W respectively. The ablation ranges at 3 seconds, 5 seconds, 7 seconds, 10 seconds, and 12 seconds of ablation are detected, and the following data are obtained:

[0105] Table 1

[0106]

[0107] Table 2

[0108]

[0109] Table 3

[0110]

[0111]

[0112] Table 4

[0113]

[0114] Table 5

[0115]

[0116] Table 6

[0117]

[0118]

[0119] Table 7

[0120]

[0121] Table 8

[0122]

[0123] Table 9

[0124]

[0125]

[0126] As can be seen from the data in Table 3 above, when L1 is equal to L3, and L1 + L2 + L3 = 14 mm, that is, when the total length is approximately one-fourth of the wavelength, a relatively ideal ablation range can be obtained. After later detection, under these conditions, the blood vessels will not show the phenomenon of partial non-closure.

[0127] The present invention and its embodiments have been described schematically above. This description is not restrictive. What is shown in the drawings is only one of the embodiments of the present invention, and the actual structure is not limited thereto. Therefore, if those of ordinary skill in the art are inspired by it and design, without creative efforts, a structural manner and an embodiment similar to the technical solution, they shall fall within the protection scope of the present invention.

Claims

1. A varicose vein ablation catheter head, comprising a microwave needle (101), an insulating sleeve (102), a metal sleeve (103), and an outer sleeve (104) which are coaxially connected in sequence from the head end to the tail end; characterized in that: A cable is coaxially arranged inside the outer sleeve (104); the front end of the inner conductor (109) of the cable passes through the metal sleeve (103) and the insulating sleeve (102) and is connected to the tail end (110) of the microwave needle; the outer conductor (108) of the cable is connected to the metal sleeve (103); The cable is used to connect microwave generating equipment with a microwave wavelength of λ; The tail end (110) of the microwave needle is located in the insulating sleeve (102), the tail end of the insulating sleeve (102) is located in the metal sleeve (103), and the tail end of the metal sleeve (103) is located in the outer sleeve (104); The axial length of the exposed part of the first end of the microwave needle is L1, the axial length of the exposed part of the first end of the insulating sleeve is L2, and the axial length of the exposed part of the first end of the metal sleeve is L3; in: L1=L3±0.4mm; L2≥2mm; L1+L2+L3=n*(1 / 5~3 / 10)λ, where n is a positive integer.

2. The varicose vein ablation catheter head according to claim 1, characterized in that: L1 is equal to L3, L1+L2+L3=n*λ / 4.

3. The varicose vein ablation catheter tip according to claim 1, characterized in that: L2 is 2 to 3 mm.

4. The varicose vein ablation catheter tip according to claim 1, characterized in that: The tail end of the metal sleeve (103) extends relative to the tail end of the insulating sleeve (102) toward the tail end of the catheter head, and the extension length is L5, wherein L5≥3mm; The outer conductor (108) of the cable is connected to the tail end of the metal sleeve (103) and the tail end of the insulating sleeve (102), and the insulating sleeve (102), the metal sleeve (103) and the cable form a closed cavity (105); A thermocouple wire (107) is arranged in the outer sleeve (104), and the head end of the thermocouple wire (107) extends into the closed cavity (105) and is connected to the temperature measuring thermocouple (106) in the closed cavity (105).

5. The varicose vein ablation catheter tip according to claim 1, characterized in that: The rear end of the insulating sleeve (102) extends relative to the rear end of the microwave needle (110) towards the rear end of the catheter head, and the extension length is L6, wherein L6 is ≥ 3 mm; The tail end (110) of the microwave needle and the head end of the metal sleeve (103) are arranged alternately, and the two are blocked by the insulating sleeve (102); The plane where the head end of the metal sleeve (103) is located is taken as a reference plane, and the tail end (110) of the microwave needle head extends toward the tail end of the catheter head relative to the reference plane, and the extension length is L4, wherein L4=(3 / 10~1)L3.

6. The varicose vein ablation catheter tip according to claim 5, characterized in that: The front end of the inner conductor (109) is welded to the end surface of the microwave needle tail end (110); and the axial length of the inner conductor (109) exposed from the cable is no greater than L6.

7. The varicose vein ablation catheter tip according to any one of claims 1 to 6, characterized in that: The outer sides of the microwave needle (101), the insulating sleeve (102) and the metal sleeve (103) are coated with Teflon.

8. A varicose vein ablation catheter, characterized in that: Comprising the varicose vein ablation catheter tip as claimed in claim 7; It also includes a handle, which is provided with a temperature measuring joint (304) and a microwave joint (305); The outer sleeve (104) is connected to the housing (301) of the handle; The thermocouple wire (107) is connected to the temperature measuring joint (304); The cable is connected to the microwave connector (305).

9. The varicose vein ablation catheter according to claim 8, characterized in that: It also includes a cooling water pipe (201), which is sleeved on the outside of the cable and located on the inside of the outer sleeve (104); A water-proof layer is provided on the outside of the outer conductor (108); The cooling water pipe (201) is connected to the rear end of the metal sleeve (103); a through hole (202) is provided at one end of the cooling water pipe (201) close to the metal sleeve (103); A water inlet channel (203) is formed between the cooling water pipe (201) and the cable, and a water outlet channel (204) is formed between the cooling water pipe (201) and the outer sleeve (104); A water isolation ring (112) is provided at one end of the water inlet channel (203) close to the metal sleeve (103); The water inlet channel (203) and the water outlet channel (204) are connected via the through hole (202); The handle is also provided with a water inlet pipe (302) and a water outlet pipe (303), wherein the water inlet channel (203) is connected to the water inlet pipe (302), and the water outlet channel (204) is connected to the water outlet pipe (303).

10. The varicose vein ablation catheter according to claim 8, characterized in that: The outer side surface of the outer sleeve (104) is provided with a plurality of groups of annular scales (111); The circular scale (111) is used to indicate the length of the catheter entering and / or being removed from the vein.

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