Steam excision system and method

Abstract

This invention provides a vapor delivery system and method for treating prostate tissue. [Solution] The steam delivery system includes a steam delivery needle configured to deliver condensable steam energy to tissue. In one method, the steam delivery system is advanced transurethrally into the patient to approach the prostate tissue. The steam delivery system includes a generator unit and an induction heating system to generate high-quality steam for delivery to the tissue.

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims the benefit of U.S. Provisional Patent Application No. 62 / 109,540, entitled "Vapor Ablation System and Method," the entire disclosure of which is incorporated herein by reference.

[0002] Incorporation by Reference All publications and patent applications mentioned in this application are incorporated herein by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference.

[0003] The present invention relates to an apparatus and related methods for the treatment of benign prostatic hyperplasia using a minimally invasive approach. More particularly, the present disclosure relates to treating benign prostatic hyperplasia with vapor delivered to the prostate.

Background Art

[0004] Benign prostatic hyperplasia (BPH) is a common disease in middle - aged men and its prevalence increases with age. By age 70, more than half of men have symptoms of BPH, and microscopic evidence of prostatic hyperplasia is found in nearly 9% of men. The severity of symptoms increases with age, with moderate to severe symptoms in 27% of patients aged 60 to 70 years and 37% of patients in their 70s.

[0005] The prostate in the early life is the size and shape of a walnut and weighs approximately 20 grams before the enlargement caused by BPH (benign prostatic hyperplasia). Prostatic enlargement appears as a normal process. As men age, the prostate gradually increases in size to twice or more its normal size. The fibromuscular tissue surrounding the prostate limits the expansion after the gland reaches a certain size. Due to such limitation of expansion, the encased tissue compresses the prostatic urethra, causing it to constrict and thus creating resistance to urine flow.

[0006] In the anatomical structure of the male urogenital system, the prostate gland is located below the bladder and bladder neck. The bladder wall can expand and contract to cause the flow of urine through the urethra, which extends from the bladder through the prostate gland and penis. The portion of the urethra surrounded by the prostate gland can be called the prostatic urethra. The prostate gland also surrounds the ejaculatory ducts, which have open ends in the prostatic urethra. During sexual arousal, sperm are transported from the testicles to the prostate gland by the vas deferens, and the prostate gland provides fluid to mix with the sperm, forming semen during ejaculation. On either side of the prostate gland, the vas deferens and seminal vesicles junction to form a single tube called the ejaculatory duct. Thus, each ejaculatory duct carries seminal vesicle mucus and sperm into the prostatic urethra.

[0007] The prostate can be classified into three zones: the peripheral zone, the transitional zone, and the central zone. The peripheral zone (PZ) makes up about 70% of the volume of the male prostate. The subcapsular portion of the posterior surface of this prostate surrounds the distal urethra, and 70-80% of cancers originate in the peripheral zone tissue. The central zone (CZ) surrounds the ejaculatory duct and contains about 20-25% of the prostate volume. The central zone is often the site of inflammatory processes. The transitional zone (TZ) is where benign prostatic hyperplasia (BPH) develops and contains about 5-10% of the volume of the glandular elements in a normal prostate, but in cases of BPH, it can constitute up to 80% of the volume. The transitional zone includes two lateral prostatic lobes and the periurethral zone. Surrounding the transitional zone are the natural barriers, namely the urethroprostatic portion, the posterior fibromuscular stump, and the fibrous plane between the transitional zone and the peripheral zone. The posterior fibromuscular stump or fibromuscular zone is predominantly fibromuscular tissue.

[0008] BPH is typically diagnosed when a patient complains of bothersome difficulty urinating despite treatment. The main symptoms of BPH are increased frequency of urination and an urgent need to urinate. Furthermore, BPH can cause bladder retention, which can lead to lower urinary tract infections (LUTIs). In many cases, LUTIs progress to the kidneys, leading to chronic pyelonephritis and ultimately kidney failure. BPH can also cause sexual dysfunction associated with sleep disturbances and psychological anxiety due to severe difficulty urinating. Thus, BPH significantly alters the quality of life for men as they age.

[0009] BPH arises from an imbalance between the continuous development and spontaneous cell death (apoptosis) of prostate glandular cells. When these cells develop excessively, the prostate gland enlarges, particularly in the transition zone through which the urethral prostatic portion passes.

[0010] In its early stages, BPH can be treated to alleviate symptoms. For example, alpha-blockers treat BPH by relaxing the smooth muscles of the prostate and bladder neck, thereby making it easier for urine to flow out of the bladder. These drugs have been shown to be effective until the glandular elements cause overwhelming cell growth within the prostate.

[0011] However, in more advanced stages of BPH, treatment is limited to surgical or less invasive thermal ablation interventions. Many methods have been developed using electrosurgical or mechanical tissue resection, thermal or cryoexcision of intracapsular tissue of the prostate. In many cases, such interventions are temporary, and these treatments often result in significant perioperative discomfort and pathological conditions.

[0012] In one thermal resection method, radiofrequency (RF) energy is delivered to the prostate tissue through elongated radiofrequency needles embedded at multiple locations in the prostatic lobe. These elongated RF needles, typically about 20 mm in length, are embedded in the lobe along with an insulating material. This RF treatment ablates and removes tissue from the urethral prostatic portion. It does not target tissue parallel to or near the urethral prostatic portion. The RF energy is typically applied for 1 to 3 seconds or longer. This causes the RF energy to thermally diffuse, resecting the tissue and reaching the surrounding area of ​​the cyst. Such a method of delivering RF energy does not produce a permanent effect because the ablation is not evenly applied to the smooth muscle tissue and alpha-adrenergic receptors surrounding the urethral prostatic portion. As a result, the lobe tissue continues to grow, irritating the urethra and thus limiting the long-term effectiveness of the treatment. [Overview of the project] [Problems that the invention aims to solve]

[0013] This invention provides a vapor delivery system and method for treating prostate tissue. [Means for solving the problem]

[0014] A steam delivery system is provided, comprising: a generator unit including a cradle; a syringe assembly disposed in the cradle and configured to interact with the cradle to deliver fluid at a controlled flow rate; an induction heating system fluidically coupled to the syringe assembly and configured to receive fluid from the syringe assembly; a force sensor disposed in the cradle and / or configured to contact the cradle and / or the syringe assembly to generate an electrical signal proportional to the force exerted on the force sensor by the cradle and / or the syringe assembly; and an electronic controller configured to control the delivery of fluid and high-frequency energy to the induction heating system for steam generation, wherein the electronic controller is further configured to calibrate the electrical signal as representative of the pressure within the syringe assembly, and the electronic controller is further configured to stop the delivery of fluid and high-frequency energy to the induction heating system when the fluid pressure falls outside a desired fluid pressure range.

[0015] In some embodiments, the cradle is positioned such that when the syringe assembly is inserted into the cradle, the distal end of the syringe assembly is held at a higher height than the proximal end of the syringe assembly.

[0016] In one embodiment, the system is configured to purge air from the syringe assembly during a priming procedure in which the fluid is pushed out of the syringe assembly through the vapor delivery system.

[0017] In another embodiment, the cradle further includes a piston coupled to a linear motor, the piston interacting with the plunger of the syringe assembly to deliver fluid from the syringe assembly.

[0018] In some embodiments, the contact switch is activated when the syringe assembly is inserted into the cradle.

[0019] In one embodiment, the induction heating system includes an inner fluid coil in a position surrounded by an outer conductive coil.

[0020] A method for controlling the flow of steam is provided, the method comprising: receiving a syringe assembly in a cradle of a generator unit; discharging fluid from the syringe assembly at a controlled flow rate to an induction heating system fluidically coupled to the syringe assembly; measuring a force exerted on a force sensor positioned in the cradle and / or configured to contact the cradle and / or the syringe assembly during fluid discharging; calibrating the force measured by an electronic controller to represent the fluid pressure in the syringe assembly; and stopping the discharging of fluid to the induction heating system when the fluid pressure falls outside a desired fluid pressure range.

[0021] A method for treating prostate tissue is provided, the method comprising inserting a vapor delivery system transurethrally into the patient so as to approach the prostatic portion of the patient's urethra, advancing a vapor delivery needle generally laterally to the vapor delivery system through the prostatic portion of the urethra into the transition zone of the prostate, and delivering vapor through a distally oriented vapor delivery port of the vapor delivery needle so as to direct the vapor into the prostate distally from the vapor delivery system.

[0022] Next, in order to better understand the present invention and practical methods of carrying it out, several preferred embodiments are described, with reference to the accompanying drawings, as merely non-limiting examples. In the accompanying drawings, the same reference numerals are used for corresponding features across similar embodiments. [Brief explanation of the drawing]

[0023] [Figure 1] This figure shows one embodiment of a steam delivery system. [Figure 2A] This is a close-up view of the distal portion of the steam delivery system, including the steam delivery needle. [Figure 2B]A close-up view of the distal portion of a steam delivery system including a steam delivery needle. [Figure 2C] A diagram showing a normal prostate. [Figure 2D] A diagram showing an enlarged prostate being treated with a steam delivery system. [Figure 3A] A diagram showing a steam delivery system including an induction heating system for generating high-quality condensable steam. [Figure 3B] A diagram showing a steam delivery system including an induction heating system for generating high-quality condensable steam. [Figure 4] A diagram showing a generator unit configured to control the generation of steam in an induction heating system. [Figure 5] A diagram showing one embodiment of a syringe assembly that interacts with the generator unit. [Figure 6] A cross-sectional view of the syringe cradle of the generator unit and the syringe assembly. [Figure 7] A cross-sectional view of the shaft of the steam delivery system.

Mode for Carrying Out the Invention

[0024] Generally, one method for treating BPH involves introducing heated steam through the stroma into the interior of the prostate. The steam ablates the prostate tissue in a controllable manner. This method allows steam to be used to apply 50 cal to 300 cal of energy to each prostate lateral lobe in a procedure performed by a general practitioner. This method causes local ablation of the prostate tissue, and more specifically, localizes the thermal energy applied from the steam to excise the tissue adjacent to the urethra without damaging the prostate tissue not adjacent to the urethra.

[0025] The present invention relates to the treatment of BPH, and more particularly to a method for excising the transitional zone of prostatic tissue without excising the central and peripheral zones of the prostatic tissue. In one embodiment, the present disclosure relates to treating the prostate using convection heating in a region adjacent to the urethral prostatic portion. This excision treatment method targets smooth muscle tissue, alpha-adrenergic receptors, and sympathetic nerve structures at a depth of less than 2 cm between the bladder neck region parallel to the urethral prostatic portion and the seminal cumulus.

[0026] The system may include a steam delivery mechanism for delivering a steam medium containing water vapor. The system may use a steam source configured to provide steam at a temperature of at least 60°C to 140°C. In another embodiment, the system further includes a computer controller configured to deliver steam at intervals of 1 to 30 seconds.

[0027] In some embodiments, the system includes a source of drugs, or other chemical agents, or compounds to be delivered with the vapor. These agents may be anesthetics, antibiotics, or toxins such as Botox (Botox is a registered trademark). These agents may also be sealants, adhesives, cyanoacrylate adhesives, etc.

[0028] Figure 1 shows one embodiment of a steam delivery system. The steam delivery system 100 may have an elongated shaft 102 configured to be inserted into the patient's urethra, and a handle portion 104 for grasping with a human hand. The steam delivery system 100 may include a steam delivery needle 106 positioned on the shaft and configured to extend from the distal end of the elongated shaft 102. The steam delivery needle may extend generally perpendicular to the shaft or generally laterally to the shaft and may include one or more steam delivery ports configured to deliver a flow of a steam medium from the needle into the prostatic tissue. The steam delivery system 100 may further include one or more triggers, buttons, levers, or actuation mechanisms 107 configured to activate various functions of the system. For example, the actuation mechanism may be configured to extend / retract the steam delivery needle and to start / stop the flow of steam, suction, and a cooling and / or irrigation fluid such as saline.

[0029] In some embodiments, the trigger or actuation mechanism 107 can be operated in such a way as to control various angles or flow rates of steam and / or irrigation. In one particular embodiment, the trigger or actuation mechanism 107 may include a first trigger configured to extend / retract a steam delivery needle, a second trigger to start / stop the steam flow, and a third trigger configured to start / stop a cooling and / or irrigation fluid, such as saline solution. In another embodiment, a single trigger or actuation mechanism may perform both extending / retracting the steam delivery needle and starting / stopping the steam flow. In one embodiment, a single press or depress of a trigger, such as a trigger providing a cooling and / or irrigation fluid, such as saline solution, may provide standard irrigation, while a rapid double press or depress of a trigger may provide a “turbo” irrigation flush where the irrigation flow rate exceeds the standard irrigation flow rate. This feature can be useful, for example, when a physician encounters an obstruction requiring additional cooling, or when there is a reduced view of the urethra and / or prostate due to blood accumulation or other bodily fluids.

[0030] The fluid or irrigation source may be a saline solution or similar fluid provided through a separate lumen in the shaft to provide irrigation and flushing to the tissue during system insertion and steam delivery to the tissue. In some embodiments, irrigation may also provide cooling to the patient's urethra by direct contact of the irrigation fluid with the urethra as the fluid moves from the irrigation source through the shaft to contact the tissue, and also to the shaft of the steam delivery system. Urethral flushing may be used during lesion formation. In one embodiment, the flush flow rate may be about 80 mL / min, or in the range of 20–400 mL / min. Variations in the flush flow rate can alter the amount (depth) of tissue cooling into the urethra and prostate, which can affect the size of the lesion.

[0031] Figure 2A shows a close-up view of the distal portion of the shaft of a steam delivery system 100, which includes a steam delivery needle 106 that extends beyond the shaft and exposes a steam delivery port 108. The steam delivery ports 108 are preferably arranged in a pattern that best delivers steam to the tissue in a given application. For example, in a system designed for the treatment of BPH, the delivery ports 108 include multiple rows of multiple steam delivery ports. In one particular embodiment, the delivery ports 108 are preferably spaced at 120° intervals around the circumference of the needle, and one row of delivery ports is oriented distally from the anterior edge of the needle, as shown in Figure 2B, to ensure the resection of tissue adjacent to the urethral prostatic region. Generally, each steam delivery port is preferably of a single diameter. In one embodiment, all steam delivery ports have the same diameter.

[0032] Figure 2C shows a normal, healthy prostate, and Figure 2D shows an enlarged prostate being treated with the steam delivery system 100. In one embodiment, the steam delivery system is preferably inserted into the urethra and advanced to the urethral prostatic portion by a transurethral approach. The steam delivery needle 106 is preferably advanced into the prostatic tissue generally laterally relative to the steam delivery system. Steam is preferably generated by the steam delivery system and delivered into the prostate through the steam delivery needle. As described above, the steam delivery needle preferably has a row of steam delivery ports that are oriented distally away from the device when the steam delivery needle is extended laterally relative to the shaft of the device. Referring to Figure 2D, the steam is preferably delivered into the prostate through these distally oriented steam delivery ports to excise prostatic tissue distal to the position of the steam delivery needle in the prostate. The position of the steam delivery needle and steam delivery ports can allow for the excision of transitional zone tissue of the prostate extending distally from the position of the steam delivery needle. For example, in Figure 2D, transitional zone tissue extending beneath the bladder muscle tissue, which cannot be safely penetrated by the needle of the delivery device, is treated.

[0033] The steam delivery system 100 may include an electronic controller configured to control the generation and delivery of steam into the prostatic tissue through a steam delivery needle, through the lumen of the shaft, from a steam source, a suction source, a fluid cooling or irrigation source, a light source, and / or a supply source. In some embodiments, the electronic controller may be located on or within the steam delivery system, while in other embodiments, the electronic controller may be located separately from the system.

[0034] A steam source is preferably provided to generate a steam medium and deliver it through a steam delivery needle in order to excise tissue. In one embodiment, the steam source may be a steam generator capable of delivering a steam medium such as water vapor having a precisely controlled quality to provide a precise amount of thermal energy delivered, for example, measured in calories per second. In some embodiments, the steam source may include an induction heating system located in a steam delivery system (e.g., a handle) that inductively heats the flow medium to generate a condensable steam such as steam.

[0035] Figures 3A-3B show one embodiment of an induction heating system 320, which includes an inner fluid coil 322 (shown in Figure 3A) surrounded by an outer conductive coil 324 (Figure 3B). The inner fluid coil is preferably made from a steel tube that is good for annealing. The inner fluid coil is preferably soldered or includes solder strips to ensure conductivity between the coil windings. The outer conductive coil is preferably made of a conductive material such as electrically insulated copper Litz wire having an overall diameter in the range of 18 gauge to 22 gauge. As shown, the induction heating system 320 is preferably located within a steam delivery system, such as in a handle. The inlet portion 326 of the inner fluid coil 322 can receive a fluid, such as sterile water, from an external fluid source. The fluid is preferably passed through the inner fluid coil when an alternating or high-frequency current is applied to the outer conductive coil 324 via an electrical connection portion 325. The current flowing through the outer conductive coil can induce a current flowing through the inner fluid coil, which resistively heats the fluid within the inner fluid coil to produce high-quality condensable vapor, which is then discharged through the outlet section 328 to the vapor delivery needle.

[0036] Figure 4 shows a generator unit 40 configured to supply power and fluid to an induction heating system for steam generation. The generator unit is also connected to a steam delivery system 100 as described above to supply power and other components essential for operations such as irrigation / cooling fluid, suction, etc. The generator unit may include an electronic controller and a graphical user interface (GUI) for providing the user with operating parameters and controls during steam therapy. The generator unit may also include a syringe cradle 430 which has come to hold a syringe assembly 536 for supplying a fluid such as sterile water to the induction heating system.

[0037] The generator unit may also include an electrical connector 432, which can provide a high-frequency current to the induction heating system, provide electrical signals to and from the steam delivery system, for example, at its electrical connector, to provide a temperature measurement of the induction heating system, identify the steam delivery system, track the history of steam delivery, and prevent overuse of a given steam delivery system. The generator unit 40 may also house a peristaltic pump 435 that provides a flow of a cooling / irrigation fluid, such as saline solution, to the steam delivery system. In operation, a flexible tube 437 leads from a bag of sterile saline solution, through the peristaltic pump, through the tube, and into the steam delivery system. It is preferable that a guide or marker be provided on the peristaltic pump 435 to ensure that the tube is inserted into the path that provides flow from the bag of saline solution into the steam delivery system when the pump is operating normally.

[0038] Figure 5 shows a syringe assembly 536 that provides a precise amount of sterile water, such as sterile water, to a steam delivery system 100 for conversion into steam. The syringe assembly 536 includes a syringe 537, which has an outlet port 541 offset from the centerline of the syringe, a Luer fitting 542 that connects to a sterile saline tube on the steam delivery system, a plunger 538 that moves forward in the syringe to discharge water and moves backward in the syringe to fill the syringe with water, and an attachment rod 540 that is detachably attached to the plunger 538 during system setup for filling the syringe 537. When the syringe 537 is filled with fluid, the attachment rod 540 is discarded, and the filled syringe 537 is inserted into the cradle of the generator unit.

[0039] Figure 6 shows a cross-sectional view of the syringe cradle 430 of Figure 4, with the syringe assembly 536 of Figure 5 inserted into the cradle 430. A contact switch 654 is activated when the syringe is inserted into the cradle 430 to ensure that the syringe is in place when power is supplied to the steam delivery system. The state of the contact switch is detected through an electrical lead 652. A force sensor 644 is positioned in the cradle so that it contacts and interacts with the cradle and / or the syringe assembly 537. When the electronic controller receives a command to supply sterile water to the steam delivery system, the piston 642 of the cradle engages with the syringe plunger 538, and a linear motor attached to the piston 642 delivers sterile water from the syringe 537 through the Luer fitting 542 to a fluid tube connected to the induction heating system at a precisely controlled flow rate. As sterile water is dispensed, the syringe 537 collides with the cradle 430, which moves freely laterally within the generator 40. When the cradle 430 collides with the force sensor 644, its forward movement is hindered. The minute lateral movement of the force sensor 644 is converted into an electrical signal proportional to the force exerted on the force sensor 644 by the cradle 430. This electrical signal is transmitted through the lead 648 to the controller and calibrated as the water pressure within the syringe 537 and across the fluid tube, including within the inner coil of the induction heating system. The water pressure is monitored by an electronic controller in the generator unit 40, which is preferably configured to stop the delivery of high-frequency power and fluid to the induction heating system if the fluid pressure falls outside the desired pressure range, for example, if the fluid pressure is too low (e.g., due to a leak in the water line) or too high (e.g., due to a blockage in the water line).

[0040] Cradle 430 is configured to purge air from the fluid tube during the priming procedure, when water is pushed out of the syringe, filling and flushing the system water and vapor lines, and exiting through the vapor delivery port of the vapor delivery system. As shown in Figure 6, cradle 430 is designed to maintain the distal end of syringe 537 at a higher elevation than its proximal end when syringe 537 is inserted into the cradle, and to maintain the outlet port 541 located at the top of the syringe offset. This design causes air in the syringe to be moved to the upper distal end of the syringe under the influence of gravity, exit the syringe, and be purged from the fluid tube during the priming procedure. Removal of air from the fluid tube prevents overheating of the induction heating system and prevents loss of water volume, and therefore loss of kalo delivered to the tissue.

[0041] The electronic controller of the generator unit can be configured to control various parameters of steam delivery; for example, the controller can be configured to deliver steam at a selected flow rate, a selected pressure, or a selected amount of steam at a selected treatment interval. Further details of the steam delivery system, steam generator, and how steam and fluids are delivered to the tissue can be found in U.S. Patent No. 8,273,079 and PCT Publication No. WO2013 / 040209, both of which are incorporated into this application by indicating the source. In some embodiments, the electronic controller can also control the suction and / or cooling irrigation functions of the steam delivery system.

[0042] Figure 7 provides a cross-sectional view of the elongated shaft 102 of the steam delivery system 100 from Figures 1-2. The lumen 148 is preferably configured to accommodate the steam delivery needle described above, and in Figures 1-2, it is preferably configured so that the steam delivery needle advances from the shaft during steam delivery. The lumen 115 formed within the tube 112 is preferably having a diameter in the range of about 2-5 mm to accommodate various endoscopes 118 and to provide an annular space 138 for the irrigation fluid to flow within the lumen 115 and outward from the shaft into the distal urethra and bladder. The lumen 115 is preferably sized to accommodate an endoscope or camera to provide the physician with an additional field of view and feedback. This endoscope or camera can provide an image of the distal end of the shaft, including an image of the steam delivery needle, when deployed. As can be seen in Figure 7, the lumen 115 is sized and shaped to provide space 138 for fluid irrigation flow around the endoscope 118. The annular space 138 allows for the flow of irrigation fluid from the fluid delivery system into the tissue and also provides cooling to the shaft as steam is delivered into the tissue from the steam delivery needle (located in the lumen 148). The material 144 in Figure 7 can transfer heat from the steam delivery needle to the irrigation and / or cooling fluid flowing through the annular space 138, or transfer cooling from the irrigation / cooling fluid to the steam delivery needle to prevent overheating of the patient (particularly the urethra) during steam therapy.

[0043] While specific embodiments of the present invention have been described in detail above, it should be understood that the above description of the present invention is for illustrative purposes only and is not exhaustive. Certain features of the present invention are shown in some drawings and not in others, for convenience only, and any features may be combined with other embodiments of the present invention. Many variations and modifications will be obvious to those skilled in the art. Such variations and modifications are considered to fall within the scope of the claims. Certain features described in the dependent claims can be combined with the scope of the present invention and fall within its scope. The present invention further includes embodiments in which the dependent claims are written in a multiple dependency format with respect to other independent claims. [Explanation of Symbols]

[0044] 40 Generator Unit 100 Steam delivery system 102 Long and slender shaft 104 Handle section 106 Steam delivery needle 320 Induction Heating System 430 Cradle 536 Syringe Assembly 537 Syringe 644 Force Sensor

Claims

1. A steam delivery system, wherein the steam delivery system is A generator unit including a cradle, A syringe assembly positioned in the cradle and configured to interact with the cradle to deliver fluid at a controlled flow rate, An induction heating system is fluidically coupled to the syringe assembly and configured to receive fluid from the syringe assembly, A force sensor disposed in the cradle, configured to contact the cradle and / or the syringe assembly to generate an electrical signal proportional to the force exerted on the force sensor by the cradle and / or the syringe assembly, A steam delivery system comprising: an electronic controller configured to control the delivery of fluid and high-frequency energy to the induction heating system for the generation of steam, wherein the electronic controller is further configured to calibrate the electrical signal as representative of the pressure within the syringe assembly, and the electronic controller is further configured to stop the delivery of fluid and high-frequency energy to the induction heating system when the fluid pressure falls outside a desired fluid pressure range.

2. The vapor delivery system according to claim 1, wherein the cradle is positioned such that when the syringe assembly is inserted into the cradle, the distal end of the syringe assembly is held at a higher height than the proximal end of the syringe assembly.

3. The vapor delivery system according to claim 2, wherein the cradle is configured to purge air from the syringe assembly during a priming procedure in which the fluid is pushed out of the syringe assembly through the vapor delivery system.

4. The vapor delivery system according to claim 1, wherein the cradle further includes a piston coupled to a linear motor, the piston interacting with a plunger of the syringe assembly to deliver fluid from the syringe assembly.

5. The vapor delivery system according to claim 1, wherein a contact switch is activated when the syringe assembly is inserted into the cradle.

6. The steam delivery system according to claim 1, wherein the induction heating system includes an inner fluid coil surrounded by an outer conductive coil.

7. A method for controlling the flow of steam, the method is The syringe assembly is placed inside the generator unit's cradle. From the syringe assembly, a fluid is delivered at a controlled flow rate to an induction heating system fluidically coupled to the syringe assembly. The force exerted on a force sensor, which is positioned in the cradle and configured to contact the cradle and / or the syringe assembly during fluid delivery, is measured. The force measured by the electronic controller to represent the fluid pressure within the syringe assembly is calibrated. A method comprising stopping the supply of fluid to the induction heating system when the fluid pressure falls outside a desired fluid pressure range.

8. A method for treating prostate tissue, the method is The vapor delivery system is inserted transurethrally into the patient so as to approach the patient's prostatic urethra. The vapor delivery needle is advanced generally laterally through the prostatic urethra into the transition zone of the prostate in relation to the vapor delivery system. A method comprising directing vapor into the prostate in a distal direction from the vapor delivery system through a vapor delivery port of a vapor delivery needle.

Images