Tubular water-cooled radiofrequency ablation electrode

Abstract

The invention provides a tubular water-cooled radiofrequency ablation electrode. The tubular water-cooled radiofrequency ablation electrode comprises an ablation working section, a radiofrequency unit and a cooling unit, the ablation working section comprises an ablation catheter base handle, a radiofrequency ablation electrode and an insulating blunt end which are connected in sequence, the radiofrequency ablation electrode is of a hollow tubular structure, the tube wall of the radiofrequency ablation electrode forms a radiofrequency emitting surface, and the top end of the radiofrequency ablation electrode is fixedly connected with the insulating blunt end in a sealed mode; the radio frequency unit comprises an electric radio frequency transmitter, an electrode inner temperature thermocouple, an electrode wire, an electrode connecting wire and a dispersed electrode plate. And the cooling unit is a circulating water cooling unit. The device is matched with a minimally invasive surgery, a laparoscope or a rectoscope, a bladder admission passage and a transurethral superior orifice, minimally invasive precise ablation of hyperplasia prostate tissue is achieved, and meanwhile urethral mucosa, submucosa and sphincter inside and outside the urethra are effectively protected. The device is particularly suitable for treating prostatic hyperplasia protruding into the bladder and has the advantages of being accurate in treatment, easy and convenient to operate, rapid in recovery and the like.

Description

Technical Field

[0001] This invention relates to the field of radiofrequency ablation electrodes for the urinary system, specifically a tubular water-cooled radiofrequency ablation electrode. Background Technology

[0002] Benign prostatic hyperplasia (BPH) is one of the most common lower urinary tract obstructive diseases in elderly men. With the increasing aging of the global population, the prevalence rate in men over 60 years of age has exceeded 50%, and is as high as 83% in those over 80 years of age. Bladder outlet obstruction (BOO) caused by BPH can lead to difficulty urinating, urinary retention, recurrent urinary tract infections, and even kidney damage, significantly reducing patients' quality of life and increasing the social medical burden.

[0003] Currently, surgical treatment for BPH primarily utilizes the transurethral approach, including transurethral resection of the prostate (TURP), transurethral plasma resection (PKRP), laser enucleation (HoLEP, ThuLEP), robotic ablation (AquaBeam, Aquablation®), and various transurethral ablation techniques (such as TUNA, TUMT, Rezūm, etc.). TURP remains considered the "gold standard," but it requires general or spinal anesthesia and carries risks such as bleeding, transurethral resection syndrome, urinary incontinence, and sexual dysfunction. While laser surgery offers good hemostasis, it is expensive and has a steep learning curve. Especially for moderate to severe prostatic hyperplasia that has clearly protruded into the bladder, transurethral instruments often present blind spots due to anatomical limitations, leading to incomplete resection, high rates of residual glandular tissue regeneration, or re-obstruction.

[0004] Radiofrequency ablation (RFA) technology uses thermal effects to cause tissue coagulation and necrosis, followed by absorption and shrinkage. It has been successfully applied in the treatment of solid tumors such as those in the liver, kidneys, and thyroid. In the past decade, scholars both domestically and internationally have attempted to use needle-type monopolar or bipolar RFA for the treatment of benign prostatic hyperplasia (BPH), but several common challenges remain: damage to the urethral mucosa, surrounding vascular nerve bundles, and internal and external urethral sphincters during ablation; lack of controllability in ablation depth and extent; difficulty in effectively treating "intravesical protrusion" type median lobe hypertrophy; and a lack of catheters specifically designed for transurethral prostate ablation.

[0005] CN114081613A proposed a method for implanting a shape memory alloy ablation needle via perineal puncture. However, this method involves a long puncture distance, limited positioning accuracy, and risks such as needle tract bleeding and rectal injury. Furthermore, it does not integrate cooling and temperature measurement functions, which can easily lead to excessive tissue damage.

[0006] On the other hand, water-cooled radiofrequency ablation technology has been widely used in the field of tumor ablation. It reduces the interface temperature and carbonization by circulating cold saline inside the electrode, promoting energy conduction to deeper tissues and thus expanding the coagulation range. However, needle-type radiofrequency ablation electrodes inevitably produce end ablation, making them unsuitable for transurethral prostate ablation. For example, patent CN220495064U proposes a composite catheter that improves ablation uniformity through internal cooling circulation combined with external micro-perfusion, but it still has significant shortcomings: First, the catheter itself does not integrate a temperature sensor, lacking real-time temperature monitoring and feedback capabilities; second, it does not fully consider the risk of high-temperature steam overflow, which may burn the urethral and bladder neck mucosa, leading to postoperative inflammation, edema, or stenosis; patent EP552934B1 proposes a transurethral thermal conduction ablation catheter. Although this technology claims to protect sphincter function, the protection of the sphincter relies on the mechanical isolation of the balloon, raising questions about its operability and limiting its effectiveness; moreover, its energy deposition is limited to the surface of the heating element (local thermal conduction), and the high temperature causes tissue coagulation and carbonization, failing to solve the problem of mucosal and submucosal tissue damage caused by high temperature at the electrode-tissue interface during radiofrequency ablation.

[0007] In summary, current technology lacks a dedicated radiofrequency ablation electrode device for the bladder approach, via the superior urethral opening, equipped with circulating cooling and real-time temperature monitoring, capable of precisely ablating protruding prostatic hyperplasia tissue into the bladder, while avoiding end-to-end ablation and effectively protecting the urethral mucosa, submucosa, and internal and external sphincter muscles. Developing such a device is expected to fill the gap in minimally invasive treatment for all types of BPH, including "intravesical protrusion," overcoming the anatomical limitations of traditional transurethral approaches, and achieving the clinical goal of effective deep ablation without thermal damage to the urethral mucosa and sphincter muscles. Summary of the Invention

[0008] To address the problems of existing technologies, this invention provides a novel tubular water-cooled radiofrequency ablation electrode incorporating a water-cooling circulation system. When used in conjunction with minimally invasive surgery, laparoscopy, or proctoscopy, via a bladder approach and through the superior urethral orifice, it achieves minimally invasive and precise ablation of enlarged prostatic tissue while effectively protecting the urethral mucosa, submucosa, and internal and external urethral sphincters. This device is particularly suitable for treating benign prostatic hyperplasia that has protruded into the bladder, offering advantages such as precise treatment, ease of operation, and rapid recovery.

[0009] This invention provides a tubular water-cooled radiofrequency ablation electrode that simultaneously and uniformly delivers radiofrequency energy to the surrounding prostate tissue through the entire tube wall, while the water cooling system pushes out heat deposition, forming a hollow columnar necrotic area surrounding the urethral mucosa. This solves the problems of trauma, uncontrollable ablation range, thermal damage to the urethral mucosa and surrounding blood vessels, nerve bundles and internal and external sphincters in the prior art, as well as the inability to handle prostate protrusion into the bladder.

[0010] This invention includes an ablation working section, a radio frequency (RF) unit, and a cooling unit. The ablation working section comprises, in sequence, an ablation catheter stem, an RF ablation electrode, and an insulating blunt head. The RF ablation electrode is a hollow tubular structure, with its tube wall forming the RF emitting surface, and its top end sealed and fixed to the insulating blunt head. The RF unit includes an electro-RF transmitter, an internal thermocouple, electrode wires, electrode connecting lines, and distributed electrode plates. The electrode wires are fixed to the inner wall of the RF ablation electrode and converge with the electrode connecting lines in parallel with the thermocouple. The electrode connecting lines are connected to the positive output terminal of the RF transmitter via cables. Several distributed electrode plates are connected to the negative output terminal of the electro-RF transmitter via cables, forming a unipolar RF circuit. The cooling unit is a circulating water cooling unit, including an inlet channel and an outlet channel located inside the ablation working section, which are respectively connected to a cooling medium source.

[0011] In a further improvement, the radiofrequency ablation electrode is a cylindrical structure made of conductive metal tubing, with an outer diameter of 4–8 mm, a wall thickness of 0.1–0.5 mm, and a length of 1–5 cm.

[0012] In a further improvement, the insulating blunt tip is a conical structure made of synthetic material, with a smooth hemispherical blind end at the top and the proximal end fixed to the radiofrequency ablation electrode by interference fit or adhesive bonding.

[0013] In a further improvement, the ablation catheter shank is provided with a proximal non-conductive fixing plate. The proximal non-conductive fixing plate is provided with an inlet hole for fixing the bottom of the inlet channel, an outlet hole for fixing the top of the outlet channel, and an electrical wire hole for fixing the electrode connecting wire and thermocouple wire.

[0014] In a further improvement, the water inlet of the near-end non-conductive porous fixing plate is located in the center, and the water outlet and wire hole are eccentrically located at the edge. Each hole is fixed with sealant or heat shrink tubing.

[0015] In a further improvement, the insulating blunt head is provided with a distal non-conductive fixing piece. The distal non-conductive fixing piece has a central hole and multiple circumferentially distributed water inlets. The central hole is used to fix the water inlet channel open at the top, and the water inlets are used to divert coolant.

[0016] The central hole of the distal non-conductive porous fixing plate is interference-fitted with the outer diameter of the water inlet channel, and the number of water inlets is 4–8, with a diameter of 0.3–0.8 mm.

[0017] In a further improvement, the thermocouple inside the electrode is a K, T, or N type miniature thermocouple, whose temperature measuring node is in thermal contact with the inner wall of the electrode, and is led out through the wire hole to connect to an external thermometer or radiofrequency ablation device.

[0018] In a further improvement, the water inlet channel and the water outlet channel are connected to the cooling medium source through external water inlet pipes and external water outlet pipes, respectively. The external water inlet pipes and the water outlet pipes are made of medical-grade synthetic materials such as polyurethane or silicone tubing, and are equipped with standard Luer connectors at the proximal end. The cooling medium source is an automatic constant low temperature water tank or a container containing an ice-water mixture, which is driven by a peristaltic pump to enter the water inlet channel inside the ablation working section through the external water inlet pipe, and then connected back to the cooling medium source through the water outlet channel and the external water outlet pipe to form a water cooling cycle.

[0019] The circulating water cooling unit is a coaxial double-layer interconnected tube. The water inlet channel is fixed by the far end fixing plate, and the water outlet channel is fixed by the near end fixing plate, forming a water level difference between the two. The water is connected through multiple water delivery holes around the far end fixing plate. The circulating peristaltic pump injects cooling water at 0–20°C into the far end inlet channel at a certain flow rate, and then returns through the near end outlet channel, continuously cooling the metal electrode tube wall and carrying away the heat generated near the radiofrequency ablation electrode.

[0020] The temperature-measuring thermocouple is closely attached to the liquid outlet channel and the side wall of the ablation electrode tube, which can obtain the temperature of the coolant on the electrode surface in real time and transmit it back to the equipment control system. When the detected temperature is ≥20℃, the system prompts to increase the pump speed or decrease the radio frequency power to ensure that the urethral mucosa is always in the safe range of about 5–40℃.

[0021] Further improvements include the use of disposable conductive adhesive electrode plates, with at least two plates connected in parallel and symmetrically applied to the patient's thigh and / or buttocks. The radio frequency transmitter operates at a frequency of 450–550 kHz, with a maximum output power of 50–200 W. The output mode is continuous or pulsed wave, and the power is adjusted in real-time based on thermocouple feedback. The target temperature is set at 10–20°C, and the power is automatically reduced or the output current is stopped when the temperature exceeds the limit. A general-purpose radio frequency generator outputs high-frequency AC power, which is connected to the cylindrical radio frequency ablation electrode via electrode connecting wires and electrode leads, forming a unipolar radio frequency closed loop with the disposable dispersed electrode plates attached to the patient's thigh or buttocks. According to Joule's Law, electrical energy is converted into heat energy, and the heat generated is proportional to the square of the current, tissue resistance, and time (formula: Heat≈I). 2 (×R×t). The cylindrical radiofrequency ablation electrode is a high-quality metal conductor with a resistance R value approaching 0, generating almost no heat when current passes through it. The surrounding prostate tissue is a poor conductor with a significant R value. Through resistance heating and high-speed ionic frictional heating, the temperature of the gland gradually rises to the effective ablation range, inducing protein denaturation, cell coagulation and necrosis. Subsequently, the necrotic tissue organizes, absorbs, and atrophies, relieving urethral obstruction. Simultaneously, a circulating cooling system consisting of inlet and outlet channels continuously supplies coolant, and with real-time monitoring and control by thermocouples, the temperature of the urethral mucosa is stabilized within a physiologically safe range, avoiding thermal damage to the mucosa, submucosal tissue, and urethral sphincter caused by high temperatures.

[0022] The beneficial effects of this invention are as follows:

[0023] 1. The cylindrical electrode employs a ring-shaped ablation mode, with its entire outer surface serving as the radiofrequency emission surface. This allows for the simultaneous and uniform delivery of radiofrequency energy to the prostate tissue surrounding the urethra. This fundamentally changes the invasive nature of traditional point- or needle-shaped electrodes, which ablate point by point or area by area, and avoids the unavoidable drawbacks of end-ablation. It creates a hollow columnar or ellipsoidal necrotic area surrounding the urethral mucosa in a single treatment, significantly expanding the treatment coverage while effectively protecting normal tissue. It can also be used for other organs and tissues requiring ablation treatment.

[0024] 2. The miniature thermocouples on the inner wall of the electrode can accurately reflect the actual working temperature of the interface between the electrode and the tissue in real time. The output power is dynamically adjusted through a built-in algorithm. Power is automatically reduced when the temperature approaches the upper limit, automatically paused when the temperature exceeds the limit, and resumed after the temperature drops, forming an intelligent closed loop of "monitoring-feedback-adjustment." This minimizes the risk of burns, perforations, or thermal damage to surrounding organs caused by overheating of the urethral mucosa and sphincter.

[0025] 3. The integrated, high-efficiency internal circulation cooling system continuously removes heat diffused from the ablated tissue to the electrode, preventing tissue vaporization, carbonization, and a sharp increase in impedance caused by excessively high electrode-tissue interface temperatures. This allows radiofrequency energy to be continuously and stably conducted to the deeper tissues, resulting in a larger and deeper effective ablation volume and significantly improved efficiency per treatment session.

[0026] 4. It can be accessed "from top to bottom" through the bladder neck, naturally avoiding the dead angle of the pubic arch and prostate. It can also complete the whole circumference ablation for moderate to severe middle lobe hyperplasia that has protruded into the bladder in one go, breaking through the bottleneck of traditional transurethral instruments that "cannot be cut or burned completely".

[0027] 5. The effective working length of the electrode varies from 1 to 5 cm. It can be matched with the scale in the laparoscopic field of view or the visual markings on the catheter. The operator can accurately select and adjust the position and length of the exposed radiofrequency emission segment of the electrode according to the imaging examination results (such as ultrasound, MRI, etc.) and intraoperative observation, so as to achieve personalized and precise treatment for different hyperplastic areas (such as the proximal verumontanum and the protrusion of the middle lobe). Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the overall structure of the cylindrical ablation electrode.

[0030] Figure 2 This is an exploded view of the cylindrical ablation electrode structure.

[0031] Figure 3 This is a schematic cross-sectional view of a tubular ablation electrode at the bladder neck.

[0032] Figure 4 This is a cross-sectional view of the prostate portion of the tubular ablation electrode.

[0033] Figure 5 This is a schematic cross-sectional view of the membranous portion of the prostatic urethra of a complex tubular ablation electrode.

[0034] Figure 6 This is a schematic diagram of the thermal field distribution of the tubular ablation electrode in an embodiment of the invention patent.

[0035] Figure 7 This is a schematic diagram illustrating the therapeutic effect of the tubular ablation electrode on ex vivo bovine liver in an embodiment of the present invention.

[0036] Figure 8 This is a schematic diagram illustrating the therapeutic effect of the tubular ablation electrode on the prostate gland in a live dog, as described in an embodiment of the present invention.

[0037] Explanation of reference numerals in the attached diagram: 1-Circular tubular radiofrequency ablation electrode; 2-Conical insulated blunt tip; 3-Ablation catheter pedicle; 4-Inlet channel; 5-Outlet channel; 6-Distal porous fixation plate; 7-Proximal porous fixation plate; 8-External inlet pipe; 9-External outlet pipe; 10-Water inlet; 11-Central hole; 12-Thermocouple; 13-Electrode lead wire; 14-Electrode connecting wire; 15-Dispersed electrode plate; 16-Inlet hole; 17-Outlet hole; 18-Electrode hole; 19-Radiofrequency electrode interface; 20-Dispersed electrode plate interface; 21-Water cooling chamber; 22-External urethral sphincter; 23-Prostate; 24-Hyperplastic tissue; 25-Urethra mucosa; 26-Bladder neck. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] This embodiment provides a tubular water-cooled radiofrequency ablation electrode via a bladder approach, such as... Figure 1-4 As shown, its specific structure is as follows:

[0040] 1. This radiofrequency ablation electrode mainly consists of the following components: a cylindrical radiofrequency ablation electrode 1, a tapered insulated blunt tip 2, an ablation catheter stem 3, a water inlet channel 4, a water outlet channel 5, a distal porous fixing plate 6, a proximal porous fixing plate 7, an external water inlet pipe 8, an external water outlet pipe 9, a temperature measuring thermocouple 12, electrode leads 13, electrode connecting wires 14, and a dispersed electrode plate 15. These components work together to achieve circulating cooling, radiofrequency energy emission, and real-time temperature monitoring.

[0041] 2. The top of the cylindrical radiofrequency ablation electrode 1 is sealed with a tapered, insulated blunt tip 2, and the end is sealed by a perforated fixing plate 7. The electrode contains an inlet channel 4 and an outlet channel 5, which together form a height difference and constitute a water cooling chamber 21. Electrode wires 13 are fixed to the inner wall of the electrode by laser welding. These wires are arranged in parallel with the temperature-sensing thermocouple 12 and ultimately converge into the electrode connection line 14.

[0042] 3. The tapered, insulated blunt tip 2 is made of materials such as PEEK, with a smooth, hemispherical blind end at the tip. Its proximal end is insulatedly connected to the cylindrical radiofrequency ablation electrode 1 via an interference fit. The distal porous fixing piece 6 is located inside the blunt tip, and it has a central hole 11 and multiple circumferentially distributed water inlet holes 10. The top of the water inlet channel 4 passes through the central hole and is fixed.

[0043] 4. The ablation catheter stem 3 is integrally molded from ABS medical plastic, integrating the electrode connection wire 14, external inlet pipe 8, and external outlet pipe 9, and is encapsulated using ABS medical plastic. The surface of the stem has annular anti-slip grooves spaced 2mm apart, facilitating one-handed operation by the surgeon through a small incision in the lower abdomen, or enabling electrode advancement, retraction, and rotation positioning with the help of a laparoscope, accurately positioning the electrode in the prostate 23. The ablation catheter is fixed by a radiofrequency electrode catheter fixing slot at the front end of the stem, and an integrated external inlet / outlet pipe fixing slot and electrode connection wire fixing slot at the end of the stem. The radiofrequency electrode interface 19 at the tail end and the Luer connector can be sealed and connected to the radiofrequency generator and cooling medium source for linkage control.

[0044] 5. The near-end multi-hole fixing plate 7 has three holes: a central water inlet hole 16 for fixing the bottom end of the water inlet channel 4; and an eccentric water outlet hole 17 and an electrical wire hole 18 for fixing the top end of the water outlet channel 5 and the lead-out electrode connection wire 14, respectively. All holes are sealed with sealant to ensure the cooling system is sealed.

[0045] 6. The cooling cycle consists of an inlet channel 4, an outlet channel 5, an external inlet pipe 8, an external outlet pipe 9, and a cooling medium source. Coolant enters the inlet channel 4 from the outside via a Luer connector and the external inlet pipe 8. It then flows through the water inlet hole 10 of the distal porous fixing plate 6 into the cavity between the inner wall of the electrode and the outlet channel, and returns via the outlet channel 5 and the external outlet pipe 9, forming a closed loop. The cooling medium is an ice-water mixture, driven by a peristaltic pump.

[0046] 7. The temperature measuring thermocouple 12 is selected from K-type, N-type or T-type miniature thermocouples. Its temperature measuring node is in thermal contact with the inner wall of the electrode, closely attached to the outer wall of the water outlet channel 5 and fixed to the side wall of the electrode with medical high temperature resistant adhesive. It is arranged in parallel with the electrode wire 13 and is connected to the electrode connecting wire 14 through the wire hole 18 of the near end fixing plate.

[0047] 8. The dispersed electrode plate 15 is a disposable conductive adhesive electrode plate, with at least two plates connected in parallel and symmetrically applied to the patient's thigh and / or buttocks. It is connected to the negative output terminal of the radiofrequency generator through the dispersed electrode plate interface 20, forming a unipolar radiofrequency closed loop with the cylindrical radiofrequency ablation electrode 1. The electrode connection line 14 can be adapted to connect with radiofrequency transmitters of different brands, adapting to the parameters of radiofrequency transmitters with operating frequencies of 450-550kHz and maximum output power of 50-200W. It supports continuous or pulse wave output modes and can adjust the power in real time according to thermocouple feedback. The target temperature is set to ≤20℃, and the power is automatically reduced or the output current is stopped when the temperature exceeds the limit.

[0048] This embodiment uses a laparoscopic-assisted transvesical approach, such as... Figure 5 and Figure 6 As shown, the specific process is as follows:

[0049] 1. Preoperative Preparation: Patient Preparation—Preoperative urinalysis, coagulation function tests, and urinary tract CT / MRI scans are performed to determine the extent, location, and urethral orifice of the hyperplastic tissue. Patients must fast for 6 hours preoperatively, undergo a cleansing enema, and receive spinal anesthesia or short-course general anesthesia such as propofol. The patient is placed in the lithotomy position, routinely disinfected and draped, and an indwelling catheter is inserted to empty the bladder. The bladder is then flushed with normal saline until the outflow is clear. Instrument Preparation—Check the integrity of all components of the device, ensuring the tubular electrode is not deformed, the insulating blunt tip is undamaged, and the cooling channel is unobstructed. Connect the electrode leads to the radiofrequency generator. Connect the external water inlet and outlet pipes to the circulating peristaltic pump and the constant temperature water-cooled chamber, respectively. Attach the dispersed electrode plates to the patient's bilateral thighs or buttocks, ensuring a tight fit without air bubbles.

[0050] 2. Instrument Insertion and Positioning: Under laparoscopic monitoring, the operating instruments are inserted through a lower abdominal puncture port. The anterior bladder wall is incised approximately 2 cm to expose the bladder neck and the superior urethral orifice. The adjusted tubular radiofrequency ablation electrode is inserted into the bladder along the laparoscopic operating channel. The electrode direction is adjusted so that the insulated blunt tip faces the superior urethral orifice. The electrode is slowly advanced until the effective working section is fully inside the prostatic urethra. The electrode position is confirmed through laparoscopic observation and preoperative imaging markings: the proximal end is aligned with the plane of the verumontanum, and the distal end covers the proliferative tissue protruding from the middle lobe into the bladder. The electrode is rotated to ensure uniform adhesion between the tube wall and the proliferative tissue, without deviation or jamming.

[0051] 3. Cooling circulation start-up: After confirming accurate positioning, turn on the circulating peristaltic pump, maintain the initial flow rate, inject cooling water into the circulation channel, observe the backflow of the water outlet channel to ensure smooth coolant circulation, and monitor the coolant temperature in real time through the temperature measurement system, initially stabilizing it at 5-20℃.

[0052] 4. Radiofrequency ablation procedure: Start the radiofrequency generator and begin ablation at the set initial power. Closely monitor three key indicators during the procedure: temperature feedback from the temperature monitoring system, patient vital signs, and tissue reaction under laparoscopy. In the initial stage of ablation, the prostate tissue shows slight congestion due to the increased temperature, and the temperature reading rises slowly. When the temperature reaches 20℃, the radiofrequency power and coolant temperature can be adjusted in real time.

[0053] 5. Zonal Ablation and Precise Control: For trilobal benign prostatic hyperplasia (left and right lobes + protruding portion of the middle lobe), a "full circumferential coverage, focused enhancement" strategy is adopted. First, the electrodes are kept fixed, and full circumferential ablation is performed for several minutes, forming a hollow columnar necrotic area surrounding the urethral mucosa. Then, by rotating and slightly advancing / retracting the electrodes, additional ablation is performed on the key area where the middle lobe protrudes into the bladder for several minutes. During this process, the tissue color change is observed through laparoscopy. When the tissue becomes a grayish-white coagulated solid, ablation in that area is stopped. The urethral mucosa temperature is maintained below 40℃ throughout the process, with no over-temperature alarms. The miniature thermocouples on the inner wall of the electrodes can accurately reflect the actual working temperature of the electrode-tissue contact interface in real time. The output power is dynamically adjusted through a built-in algorithm. When the temperature approaches the upper limit, the power is automatically reduced; when the temperature exceeds the limit, the process is automatically paused; and the power is resumed after the temperature drops, forming an intelligent closed loop of "monitoring-feedback-adjustment". This minimizes the risk of burns, perforations, or thermal damage to surrounding organs caused by overheating of the urethral mucosa 25 and external urethral sphincter 22.

[0054] 6. Ablation Termination and Device Removal: After completing the preset ablation time, first turn off the radiofrequency generator, and continue the cooling circulation for 2-5 minutes until the temperature drops below 20℃, then turn off the peristaltic pump. Slowly pull back the tubular electrode and remove it through the bladder incision. Examine the urethral prostate and bladder neck mucosa via laparoscopy to confirm the absence of complications such as bleeding, perforation, and thermal injury. Irrigate the bladder, suture the bladder incision, and leave an indwelling catheter for postoperative drainage and irrigation.

[0055] In addition to being used for bladder approach treatment of benign prostatic hyperplasia, the device of the present invention can also be used for radiofrequency ablation treatment of proliferative lesions surrounding other tubular or hollow organs and tissues, including but not limited to the trachea, esophagus, bile duct, blood vessels, etc.

[0056] Figure 6 This is a schematic diagram of the thermal field distribution of the tubular ablation electrode in an embodiment of the invention patent. Figure 6As can be seen, the tubular water-cooled radiofrequency ablation electrode provided by this invention presents a ring-shaped ablation mode, with its entire outer surface serving as a radiofrequency emitting surface, enabling simultaneous and uniform delivery of radiofrequency energy to the prostate tissue surrounding the urethra. This fundamentally changes the invasive mode of traditional point- or needle-shaped electrodes, which ablate point by point or area by area, and avoids the unavoidable drawbacks of end-ablation. It forms a hollow columnar or ellipsoidal necrotic area surrounding the urethral mucosa in one treatment, significantly expanding the treatment coverage while effectively protecting normal tissue.

[0057] Figure 7 This is a schematic diagram illustrating the therapeutic effect of the tubular ablation electrode on ex vivo bovine liver in an embodiment of the present invention. Figure 8 This is a schematic diagram illustrating the therapeutic effect of the tubular ablation electrode on the prostate gland in a live dog, as described in an embodiment of the present invention.

[0058] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on its differences from other embodiments. In particular, for the device embodiments, the above descriptions are merely preferred embodiments of the present invention. Since they are fundamentally similar to the method embodiments, the descriptions are relatively simple, and relevant parts can be referred to the descriptions of the method embodiments. The above descriptions are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention, without departing from the principle of the present invention, should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A tubular water-cooled radiofrequency ablation electrode, characterized in that: The device includes an ablation section, a radio frequency (RF) unit, and a cooling unit. The sidewalls of the ablation section form an RF emitting surface, and the top is an insulating structure. The RF unit includes an internal thermocouple, an electrode wire, and an electrode connecting wire disposed inside the ablation section. The electrode wire is fixed to the inner wall of the ablation section and runs parallel to the thermocouple into the electrode connecting wire. The electrode connecting wire forms a unipolar RF circuit with a distributed electrode plate disposed externally via an RF transmitter. The cooling unit is a circulating water cooling unit, including an inlet channel and an outlet channel disposed inside the ablation section. The inlet channel and the outlet channel are respectively connected to a cooling medium source.

2. The tubular water-cooled radiofrequency ablation electrode according to claim 1, characterized in that: The ablation working section includes an ablation catheter stem, a radiofrequency ablation electrode, and an insulating blunt tip connected in sequence. The radiofrequency ablation electrode is a hollow tubular structure, with its tube wall forming a radiofrequency emitting surface, and its top end sealed and fixed to the insulating blunt tip. The radiofrequency ablation electrode is a circular tubular structure made of conductive metal tubing, with an outer diameter of 4–8 mm, a wall thickness of 0.1–0.5 mm, and a length of 1–5 cm.

3. The tubular water-cooled radiofrequency ablation electrode according to claim 2, characterized in that: The insulating blunt tip is a conical structure made of synthetic material, with a smooth hemispherical blind end at the top and the proximal end fixed to the radiofrequency ablation electrode by interference fit or bonding.

4. The tubular water-cooled radiofrequency ablation electrode according to claim 2, characterized in that: The ablation catheter stem is provided with a proximal non-conductive fixing plate, which has an inlet hole for fixing the bottom of the inlet channel, an outlet hole for fixing the top of the outlet channel, and an electrical hole for fixing the electrode connecting wires and thermocouple wires.

5. The tubular water-cooled radiofrequency ablation electrode according to claim 4, characterized in that: The water inlet of the near-end non-conductive porous fixing plate is located in the center, and the water outlet and wire hole are eccentrically located on the edge. Each hole is fixed with sealant or heat shrink tubing.

6. The tubular water-cooled radiofrequency ablation electrode according to claim 4, characterized in that: The insulating blunt head is provided with a distal non-conductive fixing plate. The distal non-conductive fixing plate is provided with a central hole and multiple circumferentially distributed water inlets. The central hole is used to fix the water inlet channel open at the top, and the water inlets are used to divert coolant.

7. The tubular water-cooled radiofrequency ablation electrode according to claim 6, characterized in that: The central hole of the distal non-conductive porous fixing piece is interference-fitted with the outer diameter of the water inlet channel or glued together. The number of water inlets is 4–8, and the diameter of the inlets is 0.3–0.8 mm.

8. The tubular water-cooled radiofrequency ablation electrode according to claim 6, characterized in that: The circulating water cooling unit is a coaxial double-layered interconnected tube. The inlet channel is fixed by a distal fixing plate, and the outlet channel is fixed by a proximal fixing plate, creating a water level difference. The water flows through multiple water inlets around the distal fixing plate. A circulating peristaltic pump injects cooling water at a certain flow rate from the distal inlet channel to the proximal outlet channel, continuously cooling the metal electrode tube wall and removing heat generated near the radiofrequency ablation electrode. The inlet and outlet channels are connected to the cooling medium source via external inlet and outlet pipes, respectively. The external inlet and outlet pipes are made of medical-grade synthetic materials, and the proximal end is equipped with a standard Luer connector. The cooling medium source is an automatic constant-low temperature water tank or a container containing an ice-water mixture. Driven by the peristaltic pump, it enters the inlet channel inside the ablation working section through the external inlet pipe, and then returns to the cooling medium source through the outlet channel and the external outlet pipe, forming a water cooling cycle.

9. The tubular water-cooled radiofrequency ablation electrode according to claim 1, characterized in that: The unipolar radio frequency circuit includes an electro-radio frequency transmitter and distributed electrode plates. The electrode connection line is connected to the positive output terminal of the radio frequency transmitter via a cable, and several distributed electrode plates are connected to the negative output terminal of the electro-radio frequency transmitter via cables, thus forming a unipolar radio frequency circuit.

10. The tubular water-cooled radiofrequency ablation electrode according to claim 1 or 9, characterized in that: The thermocouple inside the electrode is a K, T, or N type miniature thermocouple, with its temperature measuring node in thermal contact with the inner wall of the electrode, and is led out through the wire hole to connect to an external thermometer or radiofrequency ablation device.

11. The tubular water-cooled radiofrequency ablation electrode according to claim 9, characterized in that: The dispersed electrode plate is a disposable conductive adhesive electrode plate, with at least two plates connected in parallel and symmetrically applied to the patient's thigh or buttocks.

12. The tubular water-cooled radiofrequency ablation electrode according to claim 9, characterized in that: The radio frequency transmitter operates at a frequency of 450–550kHz, with a maximum output power of 50–200W. The output mode is continuous or pulse wave. The power is adjusted in real time based on thermocouple feedback. The target temperature is set to 10–20°C. When the temperature exceeds the limit, the power is automatically reduced or the output current is stopped.

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