Varicosity ablation catheter and catheter head thereof

Abstract

The invention relates to the technical field of surgical instruments, in particular to a varicosity ablation catheter and a catheter head thereof.The catheter head comprises a microwave needle, an insulating sleeve, a metal sleeve and an outer sleeve which are coaxially connected in sequence from the head end to the tail end; a cable is coaxially arranged in the outer sleeve; the front end of an inner conductor of the cable penetrates through the metal sleeve and the insulating sleeve and is connected with the tail end of the microwave needle; the outer conductor of the cable is connected with the metal sleeve; the axial length of the exposed part of the head end of the microwave needle head 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; l1 is equal to L3 + / -0.4 mm; l2 is greater than or equal to 2mm; l1 + L2 + L3 = n * (1 / 5-3 / 10) lambda. The length of the tube head is approximate to one fourth of the wavelength, so that the ablation temperature is high, the phenomenon that the temperature cannot meet the requirement due to low microwave power can be avoided, and the phenomenon that the blood vessel cannot be closed can be avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of surgical instruments, and in particular to a varicose vein ablation catheter and a catheter head thereof. Background Art

[0002] In clinical practice, varicose vein ablation catheters are mainly used in conjunction with microwave ablation systems to achieve ablation treatment of varicose veins in the lower limbs. The working principle is that the microwave ablation system generates microwave energy, which is then transmitted through the varicose vein ablation catheter to act on the blood vessel wall. The microwave energy is converted into heat energy through the rapid rotation and mutual friction of water molecules in the tissue to coagulate the blood vessel wall until the blood vessel is closed and eventually leads to fibrosis.

[0003] When using this type of varicose vein ablation catheter made based on the principle of microwave ablation, the vein needs to be ablated section by section. Specifically, the retreat ablation method is used. After the distal end of the vein is closed, the catheter is pulled out a distance proximally to move the tube head to the area where the blood vessel is not closed, and then ablation is performed until the entire blood vessel is closed.

[0004] For example, Chinese patent publication number CN111617385A discloses a temperature-controlled varicose vein electrode with a cold cycle. When using such a product, the operator needs to perform multiple retreat ablations, which is inefficient.

[0005] After research, technicians found that the length of blood vessel closure during a single ablation directly affects the efficiency of the operation. If the length of blood vessel closure during a single ablation is short, 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, the number of operations by the operator will be significantly reduced, thereby improving efficiency.

[0006] However, as the length of a single ablation increases, the energy field distribution becomes uneven, and some areas may not be completely closed, resulting in poor varicose vein treatment results. Summary of the invention

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

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

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

[0010] A cable is coaxially arranged in the outer sleeve; the front end of the inner conductor of the cable passes through the metal sleeve and 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;

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

[0012] The tail end of the microwave needle is located in the insulating sleeve, the tail end of the insulating sleeve is located in the metal sleeve, and the tail end of the metal sleeve is located in the outer sleeve;

[0013] 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;

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

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

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

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

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

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

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

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

[0022] The plane where the head end of the metal sleeve is located is taken as the reference plane. The tail end of the microwave needle extends toward the tail end of the catheter head relative to the reference plane. The extension length is L4, where 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 from the cable is not greater than L6.

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

[0025] In the second aspect, a varicose vein ablation catheter includes the varicose vein ablation catheter head in the first aspect; it also includes a handle, the handle is provided with a temperature measuring connector and a microwave connector; the outer sleeve is connected to the shell of the handle; the thermocouple wire is connected to the temperature measuring connector; and the cable is connected to the microwave connector.

[0026] As an optional technical solution of the second aspect, it also includes a cooling water pipe, which is sleeved on the outside of the cable and located on the inside of the outer sleeve; a water-proof 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 channel is formed between the cooling water pipe and the cable, and a water outlet channel is formed between the cooling water pipe and the outer sleeve; a water isolating ring is provided at one end of the water inlet channel close to the metal sleeve;

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

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

[0031] As an optional technical solution of the second aspect, the outer side surface of the outer sleeve is provided with a plurality of groups of annular scales; the annular scales are used to indicate the length of the catheter entering and / or being removed from the vein.

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

[0033] The present invention makes the length of the tube head close to one-fourth of the wavelength, so that the ablation temperature is higher, which can avoid the temperature failing to meet the requirement due to low microwave power, thereby avoiding the phenomenon of blood vessels being unable to close.

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

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

[0036] Figure 1 This is a schematic diagram of a varicose vein ablation catheter head in one embodiment of the present application;

[0037] Figure 2 This is a schematic diagram of a varicose vein ablation catheter in one embodiment of the present application;

[0038] Figure 3 It is a schematic diagram of the force when the tail end of the microwave needle and the head end of the metal sleeve are not staggered;

[0039] Figure 4 It is a schematic diagram of the crack position when the tail end of the microwave needle and the head end of the metal sleeve are not staggered;

[0040] Figure 5 It is a schematic diagram of the bending position when the tail end of the microwave needle and the head end of the metal sleeve are not staggered.

[0041] Explanation of the symbols in the schematic diagram:

[0042] Microwaving Needles 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] Microwave needle tail end 110;

[0052] Ring scale 111;

[0053] Waterproof ring 112;

[0054] Cooling water pipe 201;

[0055] Through hole 202;

[0056] Water inlet channel 203;

[0057] Water outlet channel 204;

[0058] Housing 301;

[0059] Water inlet pipe 302;

[0060] Water outlet pipe 303;

[0061] Temperature measuring joint 304;

[0062] Microwave connector 305. DETAILED DESCRIPTION

[0063] In order to further understand the content of the present invention, the present invention is described in detail in conjunction with the accompanying drawings and embodiments.

[0064] The structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change of the proportion relationship or adjustment of the size, without affecting the effects and purposes that can be achieved by the present invention, should still fall within the scope of the technical content disclosed by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and so on quoted in this specification are only for the convenience of description, and are not used to limit the scope of implementation. The change or adjustment of their relative relationship should also be regarded as the scope of implementation of the present invention without substantially changing the technical content.

[0065] The present invention provides a varicose vein ablation catheter head, such as Figure 1 As shown, it includes 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. Optionally, the two are bonded by high-temperature glue.

[0066] The end face of the microwave needle 101 is a smooth curved surface in a hemispherical shape. When the microwave needle 101 is inserted into a blood vessel, the smooth curved surface enables the microwave needle 101 to pass through the blood vessel easily. If the end of the microwave needle 101 is sharp, the catheter is easy to get stuck in the blood vessel, resulting in poor passage.

[0067] A cable is coaxially arranged inside the outer sleeve 104, which can protect the cable. The outer sleeve 104 and the cable arranged inside the outer sleeve 104 can form a semi-rigid catheter, which can bend according to the shape of the blood vessel, so that the ablation catheter proposed in the present invention can be suitable for treating 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 a silver-plated copper alloy material, which can effectively reduce conductor attenuation and increase power capacity. The insulating layer can be made of a low-density PTFE material, which can improve microwave transmission efficiency and reduce dielectric attenuation. The outer conductor 108 is a 100% shielded ternary seamless alloy of tin, copper, and zinc, with a bending radius of up to 1.6mm, no obvious cracks when bending, and good weldability. The surface of the outer conductor 108 can be formed into a waterproof layer using a chemical PTFE plating process, which can effectively isolate the outer conductor from contact with water and improve the anti-oxidation 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 tail end 110 of the microwave needle. The outer conductor 108 is conductively connected to the metal sleeve 103. 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 connected to the microwave generating device through other adapters. The microwave generating device provides microwaves with a wavelength of λ.

[0070] The present invention is based on the application principle of microwave slot antenna, wherein a microwave needle head 101 is used as a positive electrode, an insulating sleeve 102 is used as a slot, a metal sleeve 103 is grounded, and the microwave needle head 101, the insulating sleeve 102, and the metal sleeve 103 are combined into a microwave slot antenna. The slot has the same directivity as the microwave radiation antenna. According to the magnetic field diagram analysis of the slot antenna, the energy field at the slot, i.e., the insulating sleeve 102, is the strongest and the temperature is the highest.

[0071] As for the material of the insulating sleeve 102 , as an optional solution, the insulating sleeve 102 may be a polytetrafluoroethylene sleeve.

[0072] 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, wherein 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.

[0073] Since the microwave wavelength is fixed, if the axial length of the exposed part of the microwave needle tip is excessively increased, the microwave energy will be reduced. Therefore, in order to increase the ablation length, the length of the exposed part of the microwave needle tip is usually increased locally. However, in fact, the energy of microwaves in a certain area involves many factors. Simply controlling the length cannot effectively avoid the situation where blood vessels in some areas cannot be closed.

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

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

[0076] At the same time, in this scheme, let L1+L2+L3=n*λ / 4. When n is 1, the total length of L1+L2+L3 is one-fourth of the wavelength. At this time, when it is at the peak, the microwave energy is the highest, which can avoid the phenomenon of blood vessels failing to close due to temperature not meeting the requirements.

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

[0078] When using an ablation catheter to close a blood vessel, the ablation temperature needs to be monitored in real time. If the ablation temperature cannot be controlled, 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 accurately controlled, ultrasound is often used to monitor the microwave closure process in real time, that is, to understand the treatment effect through ultrasound imaging during microwave ablation closure.

[0079] The present invention further realizes precise control of the ablation temperature by detecting the ablation temperature, so that the ablation temperature is maintained within a set range, thereby ensuring that the blood vessel can be completely closed without the need for ultrasound-assisted detection.

[0080] Specifically, the tail end of the metal sleeve 103 extends toward the tail end of the catheter head 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 disposed in the outer sleeve 104 . 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 .

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

[0083] Since the positions of the microwave needle 101 and the insulating sleeve 102 are the main areas for the microwave slot antenna to generate an external magnetic field, especially the insulating sleeve 102 has the strongest energy field and the highest temperature, if the temperature measuring thermocouple 106 is placed at the microwave needle 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 interference current in the measuring circuit of the temperature measuring thermocouple 106, affecting the measurement accuracy. Therefore, in the present invention, the tail end of the metal sleeve 103 is extended a distance of L5 relative to the tail end of the insulating sleeve 102 toward the tail end of the catheter head, and this length will not be too small. In this way, the temperature measuring thermocouple 106 placed in the closed cavity 105 formed by the insulating sleeve 102, the metal sleeve 103, and the cable will not be too close to the microwave needle 101 and the insulating sleeve 102, thereby preventing 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, thereby improving the measurement accuracy.

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

[0085] like Figure 3 As shown, if the tail end of the microwave needle head and the front end of the metal sleeve are not arranged in an interlaced manner, when the tube head is subjected to a radial force (or a force having an angle with the radial direction), the connection between the insulating sleeve 102 and the microwave needle head 101, and the insulating sleeve 102 and the metal sleeve 103 will be affected. Figure 3 The force acts in the direction indicated by the arrow.

[0086] When the product is in use, the tube head will be under high temperature conditions, and the direction of this force will change during use, that is, the tube head will bend back and forth in different directions. If the tail end of the microwave needle head of the product and the front end of the metal sleeve are not staggered, the connection between the insulating sleeve 102 and the microwave needle head 101 and the metal sleeve 103 will be subjected to lateral tension, and the direction of this lateral tension will change during use, and the connection may fail, that is, the connection is broken. Figure 4 shown.

[0087] If the product is a structure in which the tail end of the microwave needle head and the front end of the metal sleeve are not staggered, then even if the connection between the insulating sleeve 102, the microwave needle head 101 and the metal sleeve 103 is not broken, the tube head is easily deformed, that is, bent into an arc, due to the strength performance of the insulating sleeve 102. Figure 5 If the ablation catheter tip is bent into an arc, it will inevitably have an adverse effect on the directivity of the microwave slot antenna, that is, affect the actual use of the product.

[0088] In the present invention, the tail end of the insulating sleeve 102 extends toward the tail end of the catheter head relative to the tail end 110 of the microwave needle, and the extension length is L6, where L6 ≥ 3 mm. This length should not be too small, so that more space can be provided for the outer conductor 108 and the insulating sleeve 102 to be bonded by high-temperature adhesive, and the inner conductor 109 can be as close to the tail end 110 of the microwave needle as possible, and the inner conductor 109 is away from the metal sleeve 103 at the same time, so as to avoid short circuit between the inner conductor 109 and the metal sleeve 103 due to contact.

[0089] The tail end 110 of the microwave needle and the head end of the metal sleeve 103 are arranged alternately, and the overlapping position of the two is as shown in FIG. Figure 1 As shown in the dashed box. The two are blocked by the insulating sleeve 102. Taking the plane where the head end of the metal sleeve 103 is located as the reference plane, the microwave needle tail end 110 extends toward 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. If it is too small, this extension section cannot play the function of providing support. The extension length L4 should not be too large. If it is too large, the length of the connection section between the outer conductor 108 and the insulating sleeve 102 will be reduced, resulting in a reduction in the connection length between the two, and it will also make the microwave needle tail end 110 closer to the metal sleeve 103, increasing the risk of short circuit due to contact between the two.

[0090] By staggering the microwave needle tail end 110 and the front end of the metal sleeve 103, when the ablation catheter head is subjected to radial force, the microwave needle tail end 110 will provide a force in the opposite direction because the microwave needle and the metal sleeve are made of metal with high strength. The reaction force can prevent the connection between the insulating sleeve 102 and the microwave needle 101 and the metal sleeve 103 from being subjected to lateral pulling forces from different directions, 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 tail end of the metal sleeve 103 needs to be extended axially. Accordingly, the tail end 110 of the microwave needle head is staggered with the front end of the metal sleeve 103, that is, the tail end 110 of the microwave needle head is also extended axially for a certain length, so that the microwave needle head 101 can be closer to the inner conductor 109 of the coaxial cable, thereby facilitating the connection between the microwave needle head 101 and the inner conductor 109 of the cable, and reducing the difficulty of product assembly.

[0092] In addition, because the insulation layer of the cable may retreat due to scratches during assembly, the inner conductor 109 may contact the metal sleeve 103 and cause a short circuit. Therefore, the extended insulation sleeve 102 in the present application can also cover a section of the cable to avoid the phenomenon of the inner conductor 109 contacting the metal sleeve 103 and causing a short circuit, thereby improving the insulation effect of the product.

[0093] As for the connection method between the inner conductor 109 and the microwave needle 101, in one solution, 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 not greater than L6. This can prevent the inner conductor 109 from contacting the metal sleeve 103 and causing a short circuit, and can also provide space for the outer conductor 108 to be fixedly connected to the insulating sleeve 102.

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

[0095] The present invention also provides a varicose vein ablation catheter, such as Figure 2 As shown, it includes the above-mentioned varicose vein ablation catheter head and a handle, and the handle 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, for example, by high-temperature adhesive bonding.

[0096] The thermocouple wire 107 is connected to the temperature measuring joint 304. It should be noted that the thermocouple wire 107 can be directly connected to the temperature measuring joint 304 or connected to the temperature measuring joint 304 through an adapter wire.

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

[0098] Since this product is a decompression ablation procedure, a higher rod temperature will bring the risk of damaging the patient's normal tissue and scalding the operator. As an optional technical solution, 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. The cooling water pipe 201 is connected to the tail end of the metal sleeve 103, for example, by high-temperature adhesive bonding.

[0099] A through hole 202 is provided in a section of the cooling water pipe 201 near 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. The water inlet channel 203 and the water outlet channel 204 are connected through the through hole 202.

[0100] A water isolating ring 112 is provided at one end of the water inlet channel 203 close to the metal sleeve 103 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, 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. Cooling water flows from the water inlet pipe 302 into the water inlet channel 203, then enters the water outlet channel 204 through the through hole 202, and finally flows out from the water outlet pipe 303, thereby cooling.

[0102] As an optional solution, multiple groups of annular scales 111 can be provided on the outer side of the outer sleeve 104, and the annular scales 111 can indicate the length of the catheter entering and / or being withdrawn from the vein, which makes it easier to understand the position of the ablation catheter and improves the convenience of product use.

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

[0104] The microwave powers were 45W, 50W, 55W, and 60W, and the ablation ranges were detected after ablation for 3 seconds, 5 seconds, 7 seconds, 10 seconds, and 12 seconds, and the following data were 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] From the data in Table 3 above, it can be seen that when L1 is equal to L3 and L1+L2+L3=14 mm, that is, the total length is approximately one-fourth of the wavelength, a relatively ideal ablation range can be obtained. Later tests showed that under this condition, the blood vessels would not be partially unclosed.

[0127] The present invention and its embodiments are described schematically above, and the description is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by it and designs a structural method and an embodiment similar to the technical solution without creativity without departing from the purpose of the invention, they shall all 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 is ≥ 3 mm; 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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