Microwave ablation catheter for bronchoscopy

Abstract

The present invention relates to a microwave ablation catheter for bronchoscopy, belonging to the field of medical device technology. The microwave ablation catheter comprises a handle, a fixed sheath, a silicone catheter, and a microwave catheter head; the handle comprises a microwave connector, a temperature measurement connector, a water inlet pipe connector, and a water outlet pipe connector; the fixed sheath is externally placed on the silicone catheter, and the retaining sheath and the silicone catheter are placed together at the end of the handle; the silicone catheter adopts a multi-cavity silicone tube, and a memory alloy material is added to the catheter; the microwave catheter head comprises a microwave antenna, an eccentric balloon, and a temperature measurement module. The present invention provides a microwave ablation catheter for bronchoscopy, which performs intrabronchial microwave ablation combined with biliary stent placement under ERCP to increase the stent patency period and patient survival.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to a microwave ablation catheter used under a bronchoscope. Background Art

[0002] Benign and malignant tumors in the airways often cause varying degrees of airway obstruction, leading to severe breathing difficulties and complications such as obstructive pneumonia, which seriously threaten the patient's life. Traditional surgical treatment has disadvantages such as a long operation period and many postoperative complications, which seriously affect the patient's quality of life and even endanger his life. In the past decade, with the comprehensive application of modern advanced equipment and technology, the field of airway intervention has developed rapidly. Some cases of local obstruction can be recanalized through ablation technology combined with stents, radiotherapy and other technologies. These cases often achieve significant therapeutic effects: significantly improve ventilation, relieve breathing difficulties, improve activity tolerance, improve quality of life, and extend life expectancy. In recent years, with the widespread development of airway intervention technology and the continuous application of new technologies and equipment, airway tumor ablation technology has gradually formed a relatively complete technical series. Bronchoscope interventional ablation technology has the characteristics of simple operation, significant efficacy and few adverse reactions. Among them, microwave ablation technology has the advantages of accurate positioning, small contact point of the radiation head, easy control of the ablation area and relative safety. It has gradually been favored by many doctors and has been used to treat patients with bronchial lesions at home and abroad.

[0003] Microwaves used clinically are non-ionizing electromagnetic waves. Their mechanism of action is that after microwave radiation, electrolyte ions and bound charges in tissues rapidly shift relative to each other according to the microwave frequency, absorbing the microwave energy. This causes polar molecules within the tissues to oscillate at high speed. During this oscillation, to overcome the viscosity of the medium and the friction between adjacent molecules, the microwave energy is converted into heat, generating high temperatures within the tissues (up to 65°C-100°C). This high temperature can cause tuberculosis bacteria, granulation tissue, and necrotic tissue within bronchial lesions to coagulate, degenerate, necrotize, or vaporize. This results in airway dilation and accelerated sputum bacterial conversion. Furthermore, the temperature of surrounding tissues increases, leading to vasodilation and increased blood supply, promoting the absorption of local inflammation and the regeneration and repair of surrounding tissues, which is beneficial to patient recovery. Microwave therapy is primarily indicated for airway stenosis caused by benign and malignant tumors, airway granulation tissue formation, and hemostasis. Microwaves also have other immunomodulatory and anti-inflammatory effects, such as enhancing leukocyte phagocytosis, inhibiting tumor cell metastasis, and controlling the spread of inflammation.

[0004] Existing microwave therapy technology uses microwave ablation antennas to directly contact lesioned tissue for ablation. However, excessive power, prolonged treatment duration, or excessively deep or wide treatment areas can cause complications such as bronchial bleeding and perforation. Currently, these complications are mostly avoided by surgeons controlling power usage and minimizing treatment duration. Therefore, avoiding the risk of bronchial perforation and excessive burning during microwave ablation within the airway has become a pressing clinical challenge. Summary of the Invention

[0005] The purpose of the present invention is to provide a microwave ablation catheter for bronchoscopy, which can be used to perform intraluminal microwave ablation under ERCP combined with biliary stent placement to increase the stent patency period and patient survival time.

[0006] To achieve the above-mentioned purpose, according to the technical solution provided by the present invention, the microwave ablation catheter for bronchoscopy includes a handle, a fixed sheath, a silicone catheter, and a microwave catheter head; the handle includes a microwave connector, a temperature measurement connector, a water inlet pipe connector, and a water outlet pipe connector; the fixed sheath is placed on the outside of the silicone catheter, and the retaining sheath and the silicone catheter are placed together at the handle end; the silicone catheter adopts a multi-cavity silicone tube, and memory alloy material is added inside the catheter; the microwave catheter head includes a microwave antenna, an eccentric balloon, and a temperature measurement module.

[0007] Preferably, the retaining sheath is fixed to the silicone catheter near the handle end, and a check valve is provided on the retaining sheath. The check valve serves as an injection port for injecting saline solution. After the saline solution is injected into the check valve through the injection port, it reaches the eccentric balloon position. The eccentric balloon expands outward with the microwave antenna as the axis, forming an isolation cavity with the human tissue during microwave antenna heating, buffering the microwave energy and ensuring uniform heating of the treated tissue.

[0008] Preferably, the microwave duct head is molded from silicone as a whole, and the curvature can reach 60-180 degrees;

[0009] Preferably, the microwave antenna adopts a PTFE ring coaxial monopole microwave antenna with an antenna length of 10 mm. It is excited by a coaxial transmission line. The antenna only has a tangential electric field strength. The direction of the field strength is perpendicular to the radiating antenna and is distributed in a vertically symmetrical standing wave in the PTFE ring. The microwave radiation electric field can be approximately expressed as:

[0010]

[0011] Where: Eo is the peak electric field; t is the pulse width; t1 is the pulse rise time and fall time; ƒ0 is the carrier frequency.

[0012] Preferably, the silicone catheter is made of medical silicone rubber tube with added memory alloy material, with a high temperature resistance greater than 200°C, which is more than 20% of the temperature of the microwave antenna when it is heated. The catheter has a diameter of less than 2.5mm and a length of less than 1 meter.

[0013] Preferably, the maximum volume of the eccentric balloon can reach 20x15mm.

[0014] Preferably, the multi-lumen channel of the silicone catheter includes a water inlet cavity, a temperature measurement cavity, a coaxial cable cavity, and an eccentric balloon cavity;

[0015] Furthermore, the water inlet cavity is used to input cooling water into the catheter, thereby reducing the damage to the tissue around the catheter by lowering the temperature of the catheter;

[0016] The temperature measurement cavity is connected to the temperature measurement connector and the temperature measurement module, and is used to place the very fine coaxial cable of the temperature module; the temperature measurement module is placed at the bottom of the water inlet end of the eccentric balloon, and is used to monitor the degree of heating of human tissue;

[0017] The coaxial cable cavity is connected to the microwave connector and the microwave antenna, and is used for a semi-rigid coaxial cable channel that can be processed as an antenna, and also serves as a water outlet cavity for outputting cooling water in the conduit;

[0018] The balloon cavity is connected to the water injection hole and the eccentric balloon and is used for inputting physiological saline. The physiological saline is inputted into the eccentric balloon, and the eccentric balloon gradually bulges around as the amount of water injected increases.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. A microwave ablation catheter used under bronchoscopy to treat benign and malignant airway stenosis has the advantages of minimal trauma and few complications. It can effectively remove lesions, restore airway patency, and improve patients' quality of life. For patients with airway lesions who cannot tolerate surgical treatment, microwave ablation treatment through an electronic bronchoscope is a relatively safe and effective method.

[0021] 2. A microwave ablation catheter for bronchoscopy, which has an eccentric balloon water injection design and precise airbag temperature-controlled microwave ablation, avoiding direct contact of the microwave antenna with the lesion tissue. The rapid heating after the microwave is turned on will avoid the risk of excessive carbonization of the tracheal wall and perforation due to excessively high ablation temperature or prolonged ablation time of the lesion tissue.

[0022] 3. A temperature measurement module designed for a microwave ablation catheter under a bronchoscopy can accurately test the actual temperature of human tissue, so as to monitor the temperature of human tissue in real time, prevent the tissue temperature from being too high, and avoid the pain caused to the patient during the treatment process.

[0023] 4. A microwave ablation catheter used under bronchoscopy is designed to treat airway obstruction, but is not limited to the treatment of this disease. It can also be used to treat cancer thrombi formed in the esophagus, colon, gastric antrum, and bile duct. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the overall structure of the microwave catheter head after the eccentric balloon is filled with water.

[0025] Figure 2 This is a schematic diagram of the microwave catheter head after the eccentric balloon of the microwave catheter head is filled with water.

[0026] Figure 3 This is a schematic diagram of the overall structure of the eccentric balloon of the microwave catheter head without water injection.

[0027] Figure 4 This is a schematic diagram of the cross-sectional structure of the microwave guide tube head of the present invention. DETAILED DESCRIPTION

[0028] The present invention will be described in detail below with reference to the accompanying drawings.

[0029] like Figure 1 、 Figure 2 As shown, the microwave ablation catheter for bronchoscopy includes a handle 1, a fixed sheath 8, a silicone catheter 2, and a microwave catheter head 3; the handle 1 includes a microwave connector 4, a temperature measuring connector 5, a water inlet pipe connector 6, and a water outlet pipe connector 7; the fixed sheath 8 is placed externally on the silicone catheter 2, and the fixed sheath 8 and the silicone catheter 2 are placed together at the end of the handle 1; the silicone catheter 2 adopts a multi-cavity silicone tube, and a memory alloy material is added to the catheter; the microwave catheter head 3 includes a microwave antenna 9, an eccentric balloon 10, and a temperature measuring module 11.

[0030] The retaining sheath 8 is fixed to the silicone catheter 2 near the handle 1. The retaining sheath 8 is provided with a check valve 12, which serves as an injection hole for injecting physiological saline. After the physiological saline is injected into the check valve 12 through the injection port 13, it reaches the position of the eccentric balloon 10. The eccentric balloon 10 expands outward with the microwave antenna 9 as the axis. When the microwave antenna 9 heats, it forms an isolation cavity with the human tissue, buffering the microwave energy and ensuring uniform heating of the treated tissue.

[0031] The microwave catheter head 3 is molded entirely of silicone, with a curvature of 60-180 degrees. During treatment, the microwave ablation catheter is passed through a bronchoscope to the lesion site. Based on the lesion's location, an appropriate amount of saline solution is injected through a check valve 12. The saline flows through the silicone catheter's eccentric balloon cavity 17 and into the eccentric balloon 10. The eccentric balloon 10 inflates, activating microwave energy. The temperature in the microwave antenna 9's emission zone reaches 100°C, or even above 120°C, within 5 seconds. The microwave energy rapidly heats water molecules, ablating the airway lesion. The volume of the eccentric balloon 10 after water injection can reach a maximum of 20 x 15 mm.

[0032] The microwave antenna 9 adopts a polyfluoro ring coaxial monopole microwave antenna with an antenna length of 10 mm. It is excited by a coaxial transmission line. The antenna only has a tangential electric field strength. The direction of the field strength is perpendicular to the radiating antenna and is distributed in a standing wave that is symmetrical up and down in the polyfluoro ring. During ablation treatment, the ablation range is symmetrically distributed outward along the antenna axis in an elliptical shape.

[0033] The silicone tube 2 is made of a medical silicone rubber tube with a thickness of less than 2.5 mm and a memory alloy material. It does not cause foreign body reactions to human tissues, does not cause inflammation to surrounding tissues, and has a high temperature resistance of more than 200°C, which is more than 20% of the temperature of the microwave antenna when it is heated.

[0034] like Figure 3 The figure shown is a schematic diagram of the overall structure of the eccentric balloon of the microwave catheter head of the present invention without water injection. It shows the state of the microwave ablation catheter when it enters the human body. The eccentric balloon 10 is in a closed state. After the liquid is injected for ablation, a syringe can be connected to the check valve 12 to suck out the liquid in the eccentric balloon 10 and withdraw the microwave ablation catheter from the human body.

[0035] like Figure 4 As shown, the multi-lumen channel of the silicone catheter 2 includes a water inlet cavity 14, a temperature measurement cavity 15, a coaxial cable cavity 16, and an eccentric balloon cavity 17, and the cavity is formed by integrally opening a silicone mold;

[0036] The water inlet cavity 14 is used to input cooling water into the silicone catheter to reduce the temperature of the catheter and thus reduce damage to the tissue around the catheter;

[0037] The temperature measurement cavity 15 connects the temperature measurement connector 5 and the temperature measurement module 11, and is used to place the very fine coaxial cable of the temperature module; the temperature measurement module 11 is placed at the bottom of the water inlet end of the eccentric balloon 10, and is used to monitor the degree of heating of human tissue. The temperature measurement module enters the human body along with the ablation catheter. The doctor can judge the state of the tissue ablation process by the temperature, thereby controlling the ablation process and judging the ablation effect;

[0038] The coaxial cable cavity 16 connects the microwave connector 4 and the microwave antenna 9 and is used as a semi-rigid coaxial cable channel that can be processed as an antenna. It also serves as a water outlet cavity for outputting cooling water in the conduit.

[0039] The balloon cavity 17 is connected to the check valve 12 and the eccentric balloon 10 as a water injection hole, and is used to input physiological saline. When the physiological saline is input into the eccentric balloon 10, the eccentric balloon 10 gradually bulges around as the water injection amount increases.

[0040] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, improvements, and the like made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention. The scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A microwave ablation catheter for bronchoscopy, comprising a handle, a retaining sheath, a silicone catheter, and a microwave catheter head; the handle includes a microwave connector, a temperature measurement connector, a water inlet connector, and a water outlet connector; the retaining sheath is externally mounted on the silicone catheter, and the retaining sheath and silicone catheter are co-located at the end of the handle; the silicone catheter is a multi-lumen silicone tube with a memory alloy material added to the catheter; the multi-lumen silicone catheter includes a water inlet cavity, a temperature measurement cavity, a coaxial cable cavity, and an eccentric balloon cavity; The microwave catheter head includes a microwave antenna, an eccentric balloon, and a temperature measurement module. The fixed sheath is fixed to the silicone catheter near the handle end. The fixed sheath is provided with a check valve, which serves as an injection hole for injecting physiological saline. After the physiological saline is injected into the check valve through the injection port, it reaches the position of the eccentric balloon. The eccentric balloon expands outward with the microwave antenna as the axis, and is used to form an isolation cavity with human tissue when the microwave antenna is heating. The microwave antenna adopts a PTFE ring coaxial monopole microwave antenna with a length of 10 mm. It is excited by a coaxial transmission line. The antenna only has a tangential electric field strength. The direction of the field strength is perpendicular to the radiating antenna and is distributed in a vertically symmetrical standing wave in the PTFE ring. The microwave radiation electric field can be approximately expressed as: Where: Eo is the peak electric field; t is the pulse width; t1 is the pulse rise time and fall time; ƒ0 is the carrier frequency.

2. The microwave ablation catheter according to claim 1, characterized in that: The microwave duct head is molded from silicone as a whole, and the curvature can reach 60-180 degrees.

3. The microwave ablation catheter according to claim 1, wherein: The silicone tube has a high temperature resistance of greater than 200° C., which is more than 20% of the temperature of the microwave antenna when it is heated. The tube has a diameter of less than 2.5 mm and a length of less than 1 meter.

4. The microwave ablation catheter according to claim 1, characterized in that: The volume of the eccentric balloon can be up to 20x15mm at most.

5. The microwave ablation catheter according to claim 1, characterized in that: The water inlet cavity is used for inputting cooling water into the conduit.

6. The microwave ablation catheter according to claim 1, characterized in that: The temperature measurement cavity is connected to the temperature measurement connector and the temperature measurement module, and is used to place the extremely fine coaxial cable of the temperature module; the temperature measurement module is placed at the bottom of the water inlet end of the eccentric balloon, and is used to monitor the degree of heating of human tissue.

7. The microwave ablation catheter according to claim 1, characterized in that: The coaxial cable cavity is connected to the microwave connector and the microwave antenna, and is used for a semi-rigid coaxial cable channel that can be processed as an antenna. It also serves as a water outlet cavity for outputting cooling water in the conduit.

8. The microwave ablation catheter according to claim 1, characterized in that: The balloon cavity is connected to the water injection hole and the eccentric balloon.

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