Safety device for a cryoablation probe

Abstract

In one embodiment, a method for detecting leaks in a shaft of a cryoablation system includes placing a vacuum pump in fluid communication with a return tube and a supply tube; the interiors of the supply pipe and the return pipe are vacuumized; measuring a vacuum pressure within the supply tube and the return tube after evacuating for a predetermined amount of time; and analyzing the vacuum pressure to assist in identifying leaks in the system.

Description

[0001] Cross-references to related applications

[0002] This application was filed on May 23, 2024, as a PCT international patent application, with Boston Scientific Scimed, Inc., a U.S. domestic company, as the applicant for all countries, and Kyle True, Timothy A. Ostroot, Cory Ross Stenberg, Benjamin Wai-ManChan, Katrina Marie Daley, David Cory Kirt, Alexander James Wiedmann, Zachary Nickle, Jessica Bechly, and Daniel Ryan, all U.S. citizens, as inventors for all countries. This application claims priority to U.S. Provisional Application No. 63 / 468,966, filed May 25, 2023, and U.S. Application No. 18 / 671,627, filed May 22, 2024, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] The embodiments described herein relate to cryoablation systems and more specifically to safety devices for cryoablation systems. Background Technology

[0004] During cryoablation, a surgeon can deploy one or more cryoprobes to ablate target areas of a patient's anatomy by freezing and thawing tissue. In one example, the cryoprobe uses the Joule-Thomson effect to generate cooling or heating at its tip. In this case, the cryofluid in the cryoablation probe expands from a higher pressure to a lower pressure, causing the tip of the device to cool to a temperature equal to or below the temperature corresponding to the tissue being cryoablated near the tip. Heat transfer between the expanding cryofluid and the outer wall of the cryoprobe causes an ice ball to form in the tissue around the tip, which is then cryoablated. Summary of the Invention

[0005] In a first aspect, a method for detecting leakage in a shaft of a cryoablation system, wherein the shaft may include a supply tube, a return tube, and an expansion chamber toward a distal end of the shaft. The shaft may be configured to allow working fluid to travel from a proximal end of the shaft to the distal end, expand in the expansion chamber, and travel between the supply tube and the return tube back to the proximal end of the shaft. The method may include placing a vacuum pump in fluid communication with the return tube and the supply tube; evacuating the interior of the supply tube and the return tube; and measuring the vacuum pressure within the supply tube and the return tube after a predetermined amount of time has evacuated. The method may further include determining that there is likely no leakage in the shaft if the vacuum pressure is equal to or lower than a threshold pressure value; and determining that there may be leakage in the shaft if the vacuum pressure is higher than the threshold pressure value.

[0006] In a second aspect, in addition to one or more of the preceding or following aspects, or as an alternative to some aspects, the method may also include recording a leakage indication when a leakage is determined to be present in the shaft.

[0007] In the third aspect, in addition to one or more of the preceding or following aspects, or in alternatives to some aspects, the threshold pressure may be approximately 0.05 Torr (6.67 Pa).

[0008] In the fourth aspect, in addition to one or more of the preceding or following aspects, or in alternatives to some aspects, the predetermined time may be between approximately 10 seconds and approximately 45 seconds.

[0009] In a fifth aspect, in addition to one or more of the preceding or following aspects, or in alternatives to some aspects, the method may further include continuously monitoring the change of vacuum pressure over time during a predetermined period of time while evacuating the interior of the supply tube and the return tube.

[0010] In a sixth aspect, in addition to one or more of the preceding or following aspects, or in alternatives to some aspects, the method may further include determining that the shaft may not be closed at the distal end when a continuous increase in vacuum pressure toward ambient pressure is measured.

[0011] In the seventh aspect, in addition to one or more of the preceding or following aspects, or in alternatives to some aspects, the method may further include: monitoring an initial rise in vacuum pressure; monitoring, after the initial rise in vacuum pressure, detecting that the vacuum pressure has stabilized to a value above a threshold pressure value; and determining that there is a leak in the shaft.

[0012] In the eighth aspect, in addition to one or more of the preceding or following aspects, or in alternatives to some aspects, the method may further include: monitoring an initial rise in vacuum pressure; monitoring, after the initial rise in vacuum pressure, detecting that the vacuum pressure has stabilized to a value equal to or below a threshold pressure value; and determining that there is no leakage in the shaft.

[0013] In the ninth aspect, in addition to one or more of the preceding or following aspects, or in alternatives to some aspects, the method may further include: monitoring an initial rise in vacuum pressure; measuring the rate of change during the initial rise in vacuum pressure; and determining that the shaft is damaged if the rate of change is higher than a threshold rate.

[0014] In the tenth aspect, in addition to one or more of the preceding or following aspects, or in alternatives to some aspects, the method may be performed prior to the introduction of the cryoablation system into the patient.

[0015] In the eleventh aspect, in addition to one or more of the preceding or following aspects, or in alternatives to some aspects, the method may be performed after the cryoablation system has been introduced into the patient, during or after guiding the cryoablation system to the treatment site.

[0016] In the twelfth aspect, in addition to one or more of the preceding or following aspects, or in some alternatives to the aspects, the method may be performed after the first cryoablation procedure is completed with the cryoablation system and before the second cryoablation procedure is to be performed with the cryoablation system.

[0017] In a thirteenth aspect, a cryoablation system may include a working gas circuit; a vacuum chamber; a vacuum pump configured to evacuate one of the working gas circuit and the vacuum chamber; a control console configured to switch the vacuum pump between the working gas circuit and the vacuum chamber; and a pressure sensor configured to measure the vacuum pressure in the working gas circuit. The control console may also be configured to: switch the vacuum pump to the working gas circuit; control the vacuum pump to evacuate the working gas circuit; measure the vacuum pressure in the working gas circuit using the pressure sensor after a predetermined amount of time has evacuated; and determine that the shaft is damaged if the vacuum pressure exceeds a threshold pressure value.

[0018] In the fourteenth aspect, in addition to one or more of the preceding or following aspects, or in alternatives to some aspects, the console may also be configured to evacuate the working gas circuit and continuously monitor the change of vacuum pressure over time during a predetermined period.

[0019] In the fifteenth aspect, in addition to one or more of the preceding or following aspects, or in alternatives to some aspects, the console may also be configured to measure the continuous increase of vacuum pressure toward ambient pressure and determine that the shaft is not closed at the distal end.

[0020] In the sixteenth aspect, in addition to one or more of the preceding or following aspects, or in alternatives to some aspects, the console may also be configured to: monitor the initial rise in vacuum pressure; monitor, after the initial rise in vacuum pressure, detect that the vacuum pressure has stabilized to a value above a threshold pressure value; and determine that there is a leak in the shaft.

[0021] In a seventeenth aspect, a cryoablation system may be included, having a precooling fluid circuit, a working fluid circuit, a vacuum circuit, and a shaft. The shaft may include an insulating portion, wherein the vacuum circuit may be defined within the insulating portion; and an expansion chamber. The expansion chamber may include a supply pipe having a distal outlet within the expansion chamber, wherein fluid from the working fluid circuit travels through the supply pipe and expands within the expansion chamber. The expansion chamber may also include a first layer, wherein the first layer may be configured to contain fluid from the working fluid circuit; and a second layer, wherein the second layer may be configured to increase the radial strength of the expansion chamber, wherein the shaft may have a lower burst strength at a first location in the insulating portion and a higher burst strength at a second location in the expansion chamber.

[0022] In the eighteenth aspect, in addition to one or more of the preceding or following aspects, or in an alternative to some aspects, the shaft includes an inner metal tube, and a first layer may be sealed to the inner metal tube at a distal end, wherein the first position may be a sealing position located between the first layer and the inner metal tube.

[0023] In the nineteenth aspect, in addition to one or more of the preceding or following aspects, or in an alternative to some aspects, the first layer may comprise PET, and the second layer may comprise a polymer or woven material.

[0024] In the twentieth aspect, in addition to one or more of the preceding or following aspects, or in alternatives to some aspects, the cryoablation system may also include a burst valve at the first location.

[0025] This invention provides a summary of the doctrine of this application and is not intended to be a comprehensive or exhaustive discussion of the subject matter. Further details can be found in the detailed description and the appended claims. Other aspects will become apparent to those skilled in the art upon reading and understanding the following detailed description and observing the accompanying drawings, each of which should not be considered limiting. The scope of the invention is defined by the appended claims and their legal equivalents. Attached Figure Description

[0026] The various aspects of the present invention can be more fully understood in conjunction with the following accompanying drawings (Figures), wherein:

[0027] Figure 1This is a schematic diagram of a cryoablation system according to various embodiments of this document.

[0028] Figure 2 This is a schematic diagram of a portion of a cryoablation system according to various embodiments of this document.

[0029] Figure 3 This is a schematic diagram of a portion of the cryoablation axis according to various embodiments herein.

[0030] Figure 4 According to various embodiments of this document, along Figure 3 Section 4-4 is cut from the middle. Figure 3 A cross-sectional view of the axis.

[0031] Figure 5 According to various embodiments of this document, along Figure 3 Section 5-5 is cut from the middle. Figure 3 A cross-sectional view of the axis.

[0032] Figure 6 This is a schematic diagram of a biliary system according to various embodiments of this document.

[0033] Figure 7 This is a schematic diagram of the growth of an ice ball generated by a cryoablation system according to various embodiments of this document.

[0034] Figure 8 This is a schematic diagram of a portion of the cryoablation axis according to various embodiments herein.

[0035] Figure 9 This is a schematic diagram of a portion of the cryoablation axis according to various embodiments herein.

[0036] Figure 10 This is a schematic diagram of a portion of the cryoablation axis according to various embodiments herein.

[0037] Figure 11 This is a schematic diagram of a cryoablation system according to various embodiments of this document.

[0038] Figure 12 This is a schematic diagram of a console for a cryoablation system shown in various embodiments of this document.

[0039] Figure 13 This is a schematic diagram of a test apparatus for performing shaft integrity tests, as shown in various embodiments of this document.

[0040] Figure 14 This is a flowchart illustrating a method for performing a shaft integrity test according to various embodiments described herein.

[0041] Figure 15These are exemplary graphs of axial pressure versus time for three different shafts, as shown in various embodiments of this document.

[0042] Figure 16 These are exemplary graphs of axial pressure versus time for two different shafts, as shown in various embodiments of this document.

[0043] While the embodiments are adaptable to various modifications and alternatives, their specific details have been shown by way of example in the accompanying drawings and will be described in more detail. However, it should be understood that the scope of the invention is not limited to the particular aspects described. Rather, it is intended to cover modifications, equivalents, and alternatives that fall within the spirit and scope of this document. Detailed Implementation

[0044] Some cryoablation systems can be used to ablate lesions in the biliary system or other hard-to-access parts of the human anatomy. In such cases, the cryoprobe may need to traverse winding pathways. Cryoprobes with rigid shafts and sharp (piercing) tips may not be suitable for such applications. Cryoprobes with flexible shafts are possible, where the shaft may be flexible enough to access specific parts of the human anatomy, such as the biliary system, while maintaining sufficient burst strength and thermal insulation to ensure patient safety.

[0045] The value of shaft integrity testing is increasingly evident given the flexibility of catheters, which allows for travel to anatomical locations. For both flexible and rigid cryoablation probes, shaft integrity testing ensures that the cryoablation shaft is a closed system (leak-free) before pressurized cryofluid is pumped through it. Once the shaft is inserted into the patient, it is undesirable to use positive pressure to test for leaks in the cryoablation system, as pressurized gas could leak out of the system and into the patient, leading to a dangerous situation. Integrity testing is designed to prevent such situations. In various embodiments, shaft integrity testing utilizes the shaft's ability to achieve and maintain a vacuum between the supply and return tubes to determine if the probe is a closed system. If the shaft cannot achieve and maintain a sufficiently low vacuum level, a leak is determined.

[0046] Axial integrity testing can be performed after the probe has been guided to the treatment site. Therefore, axial integrity testing can identify any damage that may have occurred during the travel and / or repositioning process. Alternatively or additionally, axial integrity testing can be performed between ablation procedures, such as after the first ablation treatment and before subsequent ablation treatments.

[0047] The concepts described herein can be applied to the context of cryoablation systems described in U.S. Patent Application Publication US2021 / 00045793, entitled “Two-Stage Cryocooler,” and U.S. Patent Application Publication US2021 / 00045794, both filed on August 14, 2020, the entire contents of which are incorporated herein by reference.

[0048] Now for reference Figure 1 This document illustrates schematic diagrams of cryoablation systems according to various embodiments thereof. In various embodiments, the cryoablation system may include a handle 102 and a shaft 104. In various embodiments, the shaft 104 may be inserted into the handle 102 and may be securely attached to the handle using a shaft-handle connector 103. In various embodiments, the shaft 104 and shaft-handle connector 103 of the cryoablation system 100 may form a catheter assembly. In some embodiments, the catheter assembly includes components of the cryoablation system that are replaced each time a cryoablation procedure is performed. In some aspects, the cryoablation system 100 may include a working fluid source 110, a precooling fluid source 112, and a vacuum source 114, all of which may be connected to the cryoablation system 100.

[0049] These three sources correspond to three independent loops in the cryoablation system 100: a precooling loop, a working fluid loop, and an active vacuum loop. In some embodiments, the working fluid source 110 and the precooler fluid source 112 are connected to the base of the handle 102 of the cryoablation system 100, and the vacuum source 114 is connected near the distal end of the handle, adjacent to the shaft-handle connector 103. The cryoablation system may also include a precooling gas exhaust device 116 and a working gas exhaust device 118 connected to the handle 102. In various embodiments, the shaft-handle connector 103 serves as a manifold to ensure that each of the flow loops remains isolated from each other.

[0050] In some embodiments, the cryoablation system 100 includes a console 117. The console can be used to control the system and can be in electrical and fluid communication with the handle and cryoablation components. In some embodiments, a working fluid source 110, a precooling fluid source 112, and a vacuum source 114 can all be connected to the console 117 of the cryoablation system 100 via conduits. In some embodiments, a precooling gas exhaust device 116, a working gas exhaust device 118, or both can be connected to a conduit that carries the exhaust gas back to the console 117 or another location in the operating room, where the exhaust gas is discharged to the surrounding environment in an appropriate location. It should be noted that various sources and exhaust devices can be positioned along the handle 102 in any suitable configuration, and Figure 1 The arrangement is just one example of a suitable configuration.

[0051] Examples of the specifications and functions of each of these circuits are provided in the following paragraphs. However, it should be noted that the specific fluid and pressure values ​​are for illustrative purposes only, and other configurations are possible.

[0052] In one example, the precooling circuit may contain pressurized argon at 24.1 MPa. The precooling circuit can cool the incoming working fluid flow and can be operated in the handle. In one embodiment, the working fluid circuit may contain pressurized argon at 12.4 MPa and / or pressurized helium at 12.4 MPa. The working fluid circuit generates and / or defrosts ice balls. The working fluid circuit can be operated in the handle, the insulating portion or area of ​​the shaft, and the expansion chamber of the shaft. In one embodiment, the active vacuum can maintain a vacuum of less than or equal to 6.67 Pa. The active vacuum can insulate the shaft. The active vacuum can be operated in the insulating areas of the handle and the shaft.

[0053] In various embodiments, the working fluid circuit runs through both the handle 102 and the shaft 104 of the cryoablation system 100 and delivers fluid for generating and thawing an ice ball. The term "fluid circuit" is used throughout the application and may be replaced by a gas circuit, a liquid circuit, a fluid chamber, a gas chamber, or a liquid chamber in various embodiments. The term "fluid" is used throughout and may be replaced by a gas or a liquid in various embodiments. During ablation (cryoablation cycle), argon gas at 12.4 MPa is circulated through the probe to generate an ice ball around the expansion chamber 106 within the patient's body. The working fluid can be any suitable cooling fluid (e.g., nitrogen, air, argon, krypton, xenon, N2O, CO2, CF4). In some embodiments, the pressure of the high-pressure flow of the working fluid may be greater than or equal to 6.9 MPa, 8.3 MPa, 9.7 MPa, 11.0 MPa, 12.4 MPa, 17.2 MPa, 27.6 MPa, or 41.4 MPa. In some embodiments, the pressure of the high-pressure flow of the working fluid may be less than or equal to 55.2 MPa, 34.5 MPa, 20.7 MPa, 18.6 MPa, 16.5 MPa, 14.5 MPa, or 12.4 MPa. In some embodiments, the pressure of the high-pressure flow of the working fluid may fall within the range of 6.9 MPa to 41.4 MPa, or 8.3 MPa to 27.6 MPa, or 9.7 MPa to 16.5 MPa, or 11.0 MPa to 14.5 MPa, or may be about 12.4 MPa. Therefore, in embodiments where the working fluid is a cooling fluid, the temperature of the working fluid at the expansion chamber 106 may be about 190 Kelvin. In some embodiments, the temperature of the working fluid may be less than or equal to 250 Kelvin, 200 Kelvin, 150 Kelvin, or 100 Kelvin, or may be an amount falling within any of the above values.

[0054] In various embodiments, the precooling circuit is entirely contained within the handle 102. In various embodiments, the precooling circuit is located in the system's control console 117. In various embodiments, the precooling circuit is located in a portion of a conduit immediately proximal to the handle. In various embodiments, the precooling circuit is located in a portion of a conduit immediately distal to the handle. In various embodiments, the precooling circuit is operated using argon or any other suitable cooling fluid. In some embodiments, the pressure of the high-pressure flow of the precooling fluid may be greater than the pressure of the high-pressure flow of the working fluid. For example, the precooling fluid may be supplied at a pressure greater than about 13.8 MPa. In some embodiments, the pressure of the precooling fluid may be greater than or equal to 10.3 MPa, 13.8 MPa, 17.2 MPa, 20.7 MPa, or 24.1 MPa. In some embodiments, the pressure of the precooling fluid may be less than or equal to 31.0 MPa, 29.3 MPa, 25.9 MPa, or 24.1 MPa. In some embodiments, the pressure of the precooling fluid may fall within the range of 10.3 MPa to 31.0 MPa, or 13.8 MPa to 29.3 MPa, or 17.2 MPa to 27.6 MPa, or 20.7 MPa to 25.9 MPa, or about 24.1 MPa.

[0055] In some embodiments, the outer surface of shaft 104 may be thermally insulated from the inner surface of the shaft. In various embodiments, a vacuum circuit or vacuum chamber operates through both the handle 102 and the insulating region 105 of shaft 104. Throughout the cryoablation procedure, a vacuum is actively drawn along the insulating region 105 of shaft 104, thereby providing a protective barrier between the outer surface of shaft 104 and the patient. In alternative embodiments, shaft insulation can be achieved by circulating fluid, gas, or heating fluid throughout the shaft or by electrically heating a portion of the shaft. In alternative embodiments, shaft insulation can be achieved by containing a non-circulating fluid or gas within the insulated shaft.

[0056] The axis 104 can be of any suitable length capable of reaching the subject's target anatomical structures. In some embodiments, the axis length can be greater than or equal to 20 cm, 38 cm, 55 cm, 72 cm, or 90 cm. In some embodiments, the axis length can be less than or equal to 150 cm, 135 cm, 120 cm, 105 cm, or 90 cm. In some embodiments, the axis length can fall within the range of 20 cm to 150 cm, or 38 cm to 135 cm, or 55 cm to 120 cm, or 72 cm to 105 cm, or it can be approximately 90 cm.

[0057] In various embodiments, certain portions of shaft 104 may be flexible. In one embodiment, the entire length of the shaft may be flexible. For example, the shaft may bend about its length axis. In some such embodiments, the shaft may have a shaft diameter configured such that the shaft can be flexible enough to form a curve with a desired radius of curvature. For example, the shaft may be flexible enough such that the shaft can form a curve with a minimum radius of curvature less than or equal to 30 mm, 20 mm, 10 mm, or 5 mm.

[0058] In various embodiments, shaft 104 may include an insulating region 105 and an expansion chamber 106. The insulating region 105 defines a portion of shaft 104 that is insulated by a vacuum chamber. The expansion chamber 106 defines a portion of shaft 104 that is not insulated by a vacuum and forms an ice ball. In various embodiments, the flexible shaft delivers high-pressure working fluid from handle 102 to expansion chamber 106, where it undergoes Joule-Thomson expansion and the corresponding temperature change. The working fluid flows downward along the flexible shaft, through the handle, and then is either discharged from the control console to the atmosphere or enters and exits from the handle.

[0059] The distal end of the shaft may terminate at a distal manipulator tip 108. During use, the distal manipulator tip 108 is deployed within the patient, surrounded by tissue, and in some cases, cryoablates the tissue. In some cases, the distal manipulator tip 108 may be advantageously configured to puncture tissue. For example, the distal manipulator tip 108 may include a sharp tip, such as a cannula tip. Alternatively, the distal manipulator tip 108 may not be a sharp tip. In some embodiments, the distal manipulator tip 108 may be a non-invasive tip designed to achieve minimal tissue damage. In some embodiments, the distal manipulator tip 108 may also include a working port configured for aspiration, delivery of therapeutic agents, and delivery of other devices, including but not limited to, any one of guidewires, imaging catheters, sensing devices, biopsy devices, balloons, and stents.

[0060] Handle with pre-cooling circuit ( Figure 2 )

[0061] Now for reference Figure 2 This diagram illustrates portions of a cryoablation system according to various embodiments thereof. In some aspects, the cryoablation system 100 may include a working fluid source 110 connected to a working fluid circuit and a precooling fluid source 112 connected to a precooling fluid circuit. The working fluid circuit may include a working fluid supply conduit 210 for delivering a high-pressure flow of working fluid from the working fluid source 110 to a distal end of the shaft 104 (not shown in this view). The working fluid circuit may also include a working fluid return conduit (not shown in this view) for delivering a low-pressure flow of working fluid from the distal end of the shaft back to the base of the handle 102.

[0062] The precooling fluid circuit may include a precooling supply circuit 212 terminating at a precooling Joule-Thomson orifice 223 and delivering a high-pressure flow of precooling fluid from the precooling fluid source 112 to the precooling fluid expansion region 222 in the handle 102. The precooling fluid circuit may also include a precooling return conduit (marked by arrow 213). The precooling return conduit may be configured to deliver precooling fluid away from the precooling fluid expansion region 222 back to the base of the handle 102. The precooling return conduit may be housed together with the precooling supply circuit 212 and extends back to the console and gas manifold.

[0063] In various embodiments, a precooling fluid loop can facilitate heat exchange between the working fluid and the precooling fluid. For example, in embodiments where the working fluid expands and then cools to perform cryoablation of tissue surrounding the distal operating tip 108, the precooling fluid loop can be used to precool a high-pressure flow of the working fluid. In various embodiments, the working fluid supply conduit 210 can include a first heat exchanger 216. The first heat exchanger 216 can facilitate heat exchange between a high-pressure flow of the working fluid in the working fluid supply conduit 210 and a low-pressure flow of the precooling fluid in the precooler return conduit.

[0064] In various embodiments, the precooling supply conduit 212 may include a second heat exchanger 218 that allows heat exchange (e.g., regenerative heat exchange) between a high-pressure flow of the precooling fluid and a low-pressure flow of the precooling fluid. In various embodiments, the precooling fluid may also be a cooling fluid. In such embodiments, regenerative heat exchange between the high-pressure and low-pressure flows of the precooling fluid can remove heat from the high-pressure flow of the precooling fluid. Therefore, the second heat exchanger 218 can facilitate the precooling of the high-pressure flow of the precooling fluid.

[0065] In various embodiments, the high-pressure flow of precooled fluid exiting the second heat exchanger 218 continues through the precooled supply conduit 212 to the precooled fluid expansion region 222. Within the precooled fluid expansion region, which is entirely contained within the handle 102, the precooled supply conduit 212 terminates at a Joule-Thomson orifice. The high-pressure flow of precooled fluid can expand at or downstream of the Joule-Thomson orifice in the precooled fluid expansion region 222. The rapid drop in pressure results in a corresponding drop in temperature. The precooled fluid expansion region 222 can be in fluid communication with the precooled return conduit to deliver a low-pressure flow of the expanded precooled fluid (e.g., if the precooled fluid loop is open to the atmosphere, or if the precooled fluid loop is closed, to return to the precooled fluid source). After expansion at the Joule-Thomson orifice, the cooled precooled fluid returns through the handle 102 in the annular space between the core tube 215 and the outer surface of the handle 102. As the precooled fluid passes through the precooled return conduit, it cools the working fluid at the first heat exchanger 216.

[0066] The working fluid circuit 210 may also include a third heat exchanger 220 in the shaft 104 of the cryoablation system, which is configured for heat exchange (e.g., regenerative heat exchange) between a high-pressure flow of working fluid in the working fluid supply circuit 210 and a low-pressure flow of working fluid returning through the shaft 104 (not shown in this view).

[0067] Details of the distal apex and expansion chamber ( Figure 3 )

[0068] Now for reference Figure 3 This diagram illustrates a portion of a cryoablation shaft according to various embodiments herein. In various embodiments, the shaft includes an insulating region 105 and an expansion chamber 106. In various embodiments, the insulating region 105 of the shaft 104 includes a supply tube 324 located within a return tube 326, which is located within an insulating shaft 328. The concentric shaft configuration is designed to isolate the working fluid circuit 210 and the vacuum chamber 336 from each other.

[0069] In various embodiments, after exiting handle 102, the high-pressure flow of the working fluid travels downward along supply line 324. When the working fluid reaches working fluid expansion chamber 106, supply line 324 terminates in a Joule-Thomson orifice 332 or distal outlet 332. The high-pressure flow of the working fluid can expand at or downstream of the Joule-Thomson orifice in expansion chamber 106. The rapid drop in pressure results in a corresponding drop in temperature. Heat transfer between the expanding working fluid and the outer wall of expansion chamber 106 causes ice balls to form in the tissue around tip 108, thereby cryoablating the tissue.

[0070] Expansion chamber 106 may be in fluid communication with a working fluid return conduit (defined by the annular space between the inner surfaces of the supply conduit 324 and the return conduit 326 of the expansion chamber) to deliver a low-pressure flow of the expanded working fluid (e.g., if the working fluid circuit is open, to be discharged to the atmosphere, or if the working fluid circuit is closed, to be returned to the working fluid source). As the working fluid passes through the working fluid return conduit, it is in the third heat exchanger 220 ( Figure 2 Cooling working fluid input flow at )

[0071] In various embodiments, the working fluid is a cooling fluid and a cooling gas (e.g., nitrogen, air, argon, krypton, xenon, N2O, CO2, CF4). In this case, the high-pressure flow of the working fluid can be at a pressure such that expansion via the Joule-Thomson orifice 332 can cause the working fluid to cool to the temperature of the tissue surrounding the cryoablation expansion chamber 106. In some cases, the pressure of the high-pressure flow of the working fluid upstream of the Joule-Thomson orifice 332 can be between about 6.9 MPa and about 13.8 MPa (e.g., about 12.4 MPa). Therefore, in embodiments where the working fluid is a cooling fluid, the temperature of the working fluid after expansion from the Joule-Thomson orifice 332 can be greater than or equal to 150, 160, 170, 180, 190, or 200 Kelvin, or can be an amount falling within the range of any of the aforementioned values.

[0072] The cryoablation system 100 can be designed such that the outermost surface of the shaft does not cause thermal damage to non-target structures. In various embodiments, ice ball formation is confined to the expansion chamber 106 of the shaft 104, which may also be referred to as the active region of the device. Selective ice ball formation is achieved by evacuating the insulating region 105 of the shaft 104. In various embodiments, the cryoablation system 100 can be configured to establish a vacuum connection between the shaft 104 and the vacuum source 114.

[0073] Return to reference Figure 1 The cryoablation system 100 can be configured to be connected to a vacuum source 114 at a handle 102. In various embodiments, the vacuum source 114 is configured to evacuate along the length of the insulating region 105 of the shaft 104. In one embodiment, a vacuum is evacuated between the outer diameter of the return tube 326 and the inner diameter of the insulating shaft 328 throughout the entire insulating region 105 of the shaft 104.

[0074] In various embodiments, the vacuum source 114 is configured to evacuate at least a portion of the handle 102. This configuration insulates the handle 102 and protects the cryoablation system operator from cryogenic venting. In some embodiments, the vacuum source 114 is connected to the handle 102, and the shaft 104 is in fluid communication with the handle 102, such that evacuating the handle also empties the space between the supply tube 324 and the return tube 326. In other embodiments, the vacuum source 114 is directly connected to the shaft 104, for example, using a T-joint along the length of the shaft 104.

[0075] To provide thermal insulation along the insulating region 105 of shaft 104, the flexible shaft has a double-walled structure (the return tube is surrounded by the insulating shaft), with a small gap between the return tube 326 and the insulating shaft 328. Convective heat transfer is prevented by evacuating between the return tube and the insulating shaft, ensuring that the temperature of the working fluid does not ablate healthy, non-target patient tissue along the insulating region of the shaft or cause uncontrolled apoptosis / necrosis thereto. Sufficient thermal insulation is achieved by actively pumping air out of the gap and maintaining a vacuum of approximately 0.05 Torr. However, other vacuum pressures may be appropriate depending on the configuration of the cryoablation system. In some embodiments, a support filament 330 is wound around the outer diameter of the return tube 326. One option for the filament material is a polymer, such as polyetheretherketone (PEEK). The filament prevents direct contact between the outer surface of the return tube and the inner surface of the insulating shaft. The filament 330 minimizes thermal conduction between the inner shaft and the insulating shaft. Other alternatives may be used instead of the filament 330, such as extruded piping / co-extruded shapes or other features placed on the shaft.

[0076] In some embodiments, the shaft may not include the filament. In such embodiments, the return tube 326 and the insulating shaft 328 are selected to have sufficient material properties to minimize thermal conduction between the inner shaft and the insulating shaft.

[0077] A joint 334 is present at the junction of the insulating region 105 and the expansion chamber 106. This joint is capable of sealing the vacuum layer.

[0078] Flexible shaft cross-section, dimensions and materials ( Figure 4 )

[0079] Now for reference Figure 4 This illustrates a section taken along section 4-4 according to various embodiments herein. Figure 3 A cross-sectional view of the shaft. In various embodiments, the insulating region 105 of the shaft 104 includes a supply pipe 324 concentrically located within a return pipe 326 concentrically located within an insulating shaft 328. The insulating region 105 may include the axial portion of the vacuum chamber 336 and the insulating portion of the working gas circuit 210. In various embodiments, the vacuum chamber 336 surrounds and is isolated from the insulating portion of the working gas circuit 210.

[0080] In various embodiments, after exiting the handle 102, the high-pressure flow of the working fluid travels distally along the insulating region of the shaft via the supply pipe 324. After cooling and expanding in the expansion chamber 106, the working fluid travels proximally back through the insulating region 105 of the shaft 104 in the annular space between the supply pipe 324 and the return pipe 326.

[0081] In various embodiments, the material and size of each layer of shaft 104 can be selected to provide the shaft with sufficient flexibility to bend about its longitudinal axis at the operating temperature of the device.

[0082] In various embodiments, the supply tube 324 (also referred to herein as a capillary) is made of any suitable material or a combination of materials, such as flexible metals, polymers, composite materials, etc. In one embodiment, the supply tube 324 is made of nickel-titanium (NiTi), stainless steel, etc.

[0083] In some embodiments, the inner diameter of the supply tube 324 may be greater than or equal to 0.30 mm, 0.35 mm, 0.40 mm, or 0.45 mm. In some embodiments, the inner diameter of the supply tube 324 may be less than or equal to 0.60 mm, 0.55 mm, 0.50 mm, or 0.45 mm. In some embodiments, the diameter of the supply tube 324 may fall within the range of 0.30 mm to 0.60 mm, or 0.35 mm to 0.55 mm, or 0.40 mm to 0.50 mm, or may be approximately 0.45 mm.

[0084] In some embodiments, the outer diameter of the supply tube 324 may be greater than or equal to 0.38 mm, 0.43 mm, 0.48 mm, 0.53 mm, or 0.58 mm. In some embodiments, the outer diameter may be less than or equal to 0.78 mm, 0.73 mm, 0.68 mm, 0.63 mm, or 0.58 mm. In some embodiments, the outer diameter may fall within the range of 0.38 mm to 0.78 mm, or 0.43 mm to 0.73 mm, or 0.48 mm to 0.68 mm, or 0.53 mm to 0.63 mm, or may be approximately 0.58 mm.

[0085] In some embodiments, the thickness of the supply tube 324 may be greater than or equal to 0.10 mm, 0.11 mm, 0.12 mm, 0.14 mm, or 0.15 mm. In some embodiments, the thickness of the supply tube 324 may be less than or equal to 0.20 mm, 0.19 mm, 0.18 mm, 0.16 mm, or 0.15 mm. In some embodiments, the thickness of the supply tube 324 may fall within the range of 0.10 mm to 0.20 mm, or 0.11 mm to 0.19 mm, or 0.12 mm to 0.18 mm, or 0.14 mm to 0.16 mm, or may be approximately 0.15 mm.

[0086] In various embodiments, the return tube 326 is made of any suitable material or a combination of materials, such as flexible metals, polymers, etc. In various embodiments, the return tube 326 may be made of polyimide, fluorinated ethylene propylene (FEP), Teflon, etc. In one embodiment, the return tube 326 is formed of a polyimide material because it is highly impermeable to gases over a wide temperature range and therefore can contain the working fluid internally and maintain a vacuum externally. In a particular example, the return tube 326 is made of a braided reinforced polyimide tube to enhance gas impermeability, burst strength, and flexibility. In some embodiments, the return tube 326 is formed of a single layer of material. In some embodiments, the return tube 326 may be formed of two or more layers of material selected to optimize the performance of shaft 104. The material layers can be bonded together using any suitable technique or a combination of techniques, such as adhesives, reflow processes, etc.

[0087] In some embodiments, the outer diameter of the return tube 326 may be greater than or equal to 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, or 1.4 mm. In some embodiments, the outer diameter of the return tube 326 may be less than or equal to 1.8 mm, 1.7 mm, 1.6 mm, 1.5 mm, or 1.4 mm. In some embodiments, the outer diameter of the return tube 326 may fall within the range of 1.0 mm to 1.8 mm, or 1.1 mm to 1.7 mm, or 1.2 mm to 1.6 mm, or 1.3 mm to 1.5 mm, or may be approximately 1.4 mm.

[0088] In some embodiments, the inner diameter of the return tube 326 may be greater than or equal to 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, or 1.3 mm. In some embodiments, the inner diameter of the return tube 326 may be less than or equal to 1.7 mm, 1.6 mm, 1.5 mm, 1.4 mm, or 1.3 mm. In some embodiments, the inner diameter of the return tube 326 may fall within the range of 0.9 mm to 1.7 mm, or 1.0 mm to 1.6 mm, or 1.1 mm to 1.5 mm, or 1.2 mm to 1.4 mm, or may be approximately 1.3 mm.

[0089] In some embodiments, the thickness of the return tube 326 may be greater than or equal to 0.10 mm, 0.11 mm, 0.12 mm, 0.14 mm, or 0.15 mm. In some embodiments, the thickness of the return tube 326 may be less than or equal to 0.20 mm, 0.19 mm, 0.18 mm, 0.16 mm, or 0.15 mm. In some embodiments, the thickness of the return tube 326 may fall within the range of 0.10 mm to 0.20 mm, or 0.11 mm to 0.19 mm, or 0.12 mm to 0.18 mm, or 0.14 mm to 0.16 mm, or may be approximately 0.15 mm.

[0090] In various embodiments, the insulating shaft 328 is made of any suitable material or a combination of materials, such as flexible metals, polymers, etc. In various embodiments, the insulating shaft 328 is made of polyimide, fluorinated ethylene propylene (FEP), Teflon, etc. In particular embodiments, the insulating shaft 328 may include polytetrafluoroethylene (PTFE) and / or one or more polyether block amides (known under the trade name Pebax®, hereinafter referred to as "Pebax").

[0091] In some embodiments, the insulating shaft 328 is formed of a single layer of material. In some embodiments, the insulating shaft 328 may be formed of two or more layers of material selected to optimize the performance of the shaft 104. The material layers may be bonded together using any suitable technique or a combination of techniques, such as adhesives, reflow processes, etc.

[0092] In one embodiment, the insulating shaft can be formed using a braided reinforced polyimide tube with a thin Pebax outer layer. This three-layer construction allows for the maintenance of a deep vacuum between the return tube and the insulating shaft without causing the insulating shaft 328 to collapse onto the return tube 326.

[0093] In some embodiments, the outer diameter of the insulating shaft 328 may be greater than or equal to 1.2 mm, 1.4 mm, 1.5 mm, 1.6 mm, or 1.8 mm. In some embodiments, the outer diameter of the insulating shaft may be less than or equal to 2.2 mm, 2.1 mm, 2.0 mm, 1.9 mm, or 1.8 mm. In some embodiments, the outer diameter of the insulating shaft may fall within the range of 1.3 mm to 2.3 mm, or 1.4 mm to 2.1 mm, or 1.5 mm to 2.0 mm, or 1.6 mm to 1.9 mm, or may be approximately 1.8 mm.

[0094] In some embodiments, the inner diameter of the insulating shaft 328 may be greater than or equal to 1.0 mm, 1.2 mm, 1.3 mm, 1.4 mm, or 1.6 mm. In some embodiments, the inner diameter of the insulating shaft 328 may be less than or equal to 2.2 mm, 2.0 mm, 1.9 mm, 1.8 mm, or 1.6 mm. In some embodiments, the inner diameter of the insulating shaft 328 may fall within the range of 1.0 mm to 2.2 mm, or 1.2 mm to 2.0 mm, or 1.3 mm to 1.9 mm, or 1.4 mm to 1.8 mm, or may be approximately 1.6 mm.

[0095] In some embodiments, the thickness of the insulating shaft 328 may be greater than or equal to 0.10 mm, 0.11 mm, 0.12 mm, 0.14 mm, or 0.15 mm. In some embodiments, the thickness of the insulating shaft 328 may be less than or equal to 0.20 mm, 0.19 mm, 0.18 mm, 0.16 mm, or 0.15 mm. In some embodiments, the thickness of the insulating shaft 328 may fall within the range of 0.10 mm to 0.20 mm, or 0.11 mm to 0.19 mm, or 0.12 mm to 0.18 mm, or 0.14 mm to 0.16 mm, or may be approximately 0.15 mm.

[0096] In some embodiments, PEEK filaments 330 are wound around the return tube 326. The pitch of the PEEK filaments 330 may be greater than or equal to 0.5 mm, 1.0 mm, 1.5 mm, or 2.0 mm, or may be an amount falling within any of the aforementioned values. Alternatively, the filaments may be a plurality of discrete pieces attached along the return tube 326. The PEEK filaments 330 prevent direct contact between the return tube 326 and the insulating shaft 328, thereby maintaining their coaxial alignment. In some embodiments, an adhesive (e.g., Loctite) is applied to the filaments at the ends of the return tube 326 and the insulating shaft 328 to attach the PEEK filaments 330. In various embodiments, the PEEK filament winding is configured to minimize or prevent conductive heat transfer from the return tube to the insulating shaft. In alternative embodiments, other insulating polymers may be used as substitutes for the PEEK filaments, such as expanded PTFE (ePTFE), nylon, etc.

[0097] In some embodiments, the diameter of the PEEK filament 330 may be greater than or equal to 0.002 mm, 0.004 mm, or 0.005 mm. In some embodiments, the diameter of the PEEK filament 330 may be less than or equal to 0.007 mm, 0.006 mm, or 0.005 mm. In some embodiments, the diameter of the PEEK filament 330 may fall within the range of 0.002 mm to 0.007 mm, or 0.004 mm to 0.006 mm, or may be approximately 0.005 mm.

[0098] Shaft in expansion chamber ( Figure 5 )

[0099] Now for reference Figure 5 This illustrates sections taken along section 5-5 according to various embodiments herein. Figure 3 A cross-sectional view of the axis. Figure 5 The cross-sectional view depicts the expansion chamber 106 of shaft 104. In various embodiments, the expansion chamber 106 is located distal to the insulating region 105 along shaft 104. The expansion chamber 106 may include an expansion portion of the working fluid circuit 210.

[0100] In various embodiments, after exiting the handle 102, the high-pressure flow of the working fluid travels downward along the supply line 324. After cooling and expanding in the expansion chamber 106, the working fluid travels downward through the expansion chamber 106 and returns in the annular space between the supply line 324 and the outer wall of the expansion chamber. In various embodiments, the expansion chamber 106 is configured to maximize heat transfer between the working gas and the patient tissue by optimizing parameters such as wall thickness and material.

[0101] In various embodiments, the expansion chamber 106 is made of any suitable material or a combination of materials, such as flexible metals, polymers, etc. In various embodiments, the expansion chamber 106 is made of polyimide, fluorinated ethylene propylene (FEP), Teflon, etc. In some embodiments, the expansion chamber 106 includes a continuation of the return tube 326 of the insulating region 105 of the shaft 104. Alternatively, the expansion chamber is a separate component from the return tube 326, which can be connected to the flexible shaft 104 using any suitable joints and / or fittings, such as reflow processes, glue joints, brazing joints, or any other suitable mechanical connection process capable of withstanding cryogenic pressure and temperature.

[0102] In some embodiments, the expansion chamber 106 is formed of a single layer of material. In some embodiments, the expansion chamber 106 is formed of two or more layers of material. The material layers can be bonded together using any suitable technique or a combination of techniques, such as adhesives, reflow processes, etc.

[0103] In some embodiments, the outer diameter of the expansion chamber 106 may be greater than or equal to 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, or 1.7 mm. In some embodiments, the outer diameter of the expansion chamber 106 may be less than or equal to 2.1 mm, 2.0 mm, 1.9 mm, 1.8 mm, or 1.7 mm. In some embodiments, the outer diameter of the expansion chamber 106 may fall within the range of 1.3 mm to 2.1 mm, or 1.4 mm to 2.0 mm, or 1.5 mm to 1.9 mm, or 1.6 mm to 1.8 mm, or may be approximately 1.7 mm.

[0104] In some embodiments, the inner diameter of the expansion chamber 106 may be greater than or equal to 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, or 1.4 mm. In some embodiments, the inner diameter of the expansion chamber 106 may be less than or equal to 1.8 mm, 1.7 mm, 1.6 mm, 1.5 mm, or 1.4 mm. In some embodiments, the inner diameter of the expansion chamber 106 may fall within the range of 1.0 mm to 1.8 mm, or 1.1 mm to 1.7 mm, or 1.2 mm to 1.6 mm, or 1.3 mm to 1.5 mm, or may be approximately 1.4 mm.

[0105] In some embodiments, the thickness of the wall of the expansion chamber 106 may be greater than or equal to 0.20 mm, 0.22 mm, 0.25 mm, 0.28 mm, or 0.30 mm. In some embodiments, the thickness of the wall of the expansion chamber 106 may be less than or equal to 0.40 mm, 0.38 mm, 0.35 mm, 0.32 mm, or 0.30 mm. In some embodiments, the thickness of the wall of the expansion chamber 106 may fall within the range of 0.20 mm to 0.40 mm, or 0.22 mm to 0.38 mm, or 0.25 mm to 0.35 mm, or 0.28 mm to 0.32 mm, or may be approximately 0.30 mm.

[0106] Example of treatment area ( Figure 6 )

[0107] The cryoablation system and structure described herein are flexible and well-suited for cryoablation of areas along body cavities, blood vessels, or channels. This cryoablation system 100 is configured to be sufficiently flexible to approach and ablate many different such structures. The expansion chamber can be shaped and sized to generate ice balls or ice columns with appropriate geometry to ablate structures along the length of the body cavity. Furthermore, the materials and configuration of the probes described herein are selected to protect patient tissue and withstand high operating pressures and low temperatures.

[0108] Now for reference Figure 6 This diagram illustrates a biliary system according to various embodiments thereof. The biliary system includes organs and ducts that produce and store bile (a fluid produced by the liver to help digest fats) and release it into the small intestine. The biliary system includes the gallbladder and bile ducts inside and outside the liver.

[0109] Cholangiocarcinoma, or bile duct cancer, is a rare disease in which cancer cells form in the bile ducts. Treatment outcomes for bile duct cancer are generally poor. Current treatment options, such as Whipple's procedure or bile duct drainage, are high-risk and often ineffective.

[0110] Cryoablation is a promising treatment for cholangiocarcinoma. This cryoablation system 100 is configured with sufficient flexibility to approach and ablate the patient's bile duct. The expandable chamber can be set in shape and size to generate an ice ball with appropriate geometry to ablate the tumor in the bile duct.

[0111] In addition to treating cholangiocarcinoma, the cryoablation system 100 can be used to treat a variety of conditions, including other cancerous tumors (e.g., skin, liver, kidney, bone, lung, prostate, and breast), pain, skin conditions (e.g., atypical nevi, warts, skin tags, or actinic keratosis), and cardiac arrhythmias. The cryoablation system 100 can also ablate benign masses, soft tissue, and healthy tissue.

[0112] Ice hockey formation ( Figure 7 )

[0113] Now for reference Figure 7 This diagram illustrates the growth of ice balls generated by a cryoablation system according to various embodiments of this document. Cryoablation is defined as the use of low temperatures to destroy cells. Ice balls form in the expansion chamber of the cryoablation system, which freezes intracellular and extracellular material to temperatures below 173 Kelvin. The application of these extremely low temperatures leads to cell death. Sufficiently low ablation temperatures must be achieved to induce complete cell death. Lethal temperatures for various tissues have been reported to be between 253 and 233 Kelvin.

[0114] Figure 7 The growth of the ice ball during a cryoablation procedure is illustrated. The time points in this example are 60 seconds, 120 seconds, 180 seconds, and 240 seconds. Isotherms at 273 Kelvin, 253 Kelvin, and 233 Kelvin are plotted for each time interval. As the cryoablation procedure progresses over time, the overall size of the ice ball increases. More importantly, the cell-killing isotherms (253 Kelvin and 233 Kelvin isotherms) grow along the long and short axes of the ice ball.

[0115] It should be noted that Figure 7 The given times and temperatures are for illustrative purposes only. Ice ball formation can be based on the configuration of the cryoablation system and changes in the patient's tissue. Furthermore, ice ball growth can stabilize after a certain ablation time. For example, in some embodiments, the ice ball may reach its maximum diameter approximately 10 minutes after tissue ablation. In some embodiments, the operator of the cryoablation system may terminate the cryoablation procedure when the ice ball reaches its maximum size. In some embodiments, the operator of the cryoablation system may continue the cryoablation procedure for a predetermined amount of time after the ice ball reaches its maximum size, as maintaining tissue at low temperatures for a longer period may have therapeutic benefits.

[0116] In some embodiments, ice pucks are produced, then thawed, and then produced again. In some embodiments, active thawing is used, while in others, passive thawing is used.

[0117] exist Figure 7In the example, the ice puck is elliptical in shape (e.g., it is longer along the primary axis than along the secondary axis). The primary axis of the ice puck corresponds to the length axis of the expansion chamber. The ratio of the height to the diameter of the expansion chamber can be correlated with the shape of the ice puck. In particular, an expansion chamber that is much longer than its width will produce a more elliptical ice puck. Such an ice puck is generally more suitable for treating cholangiocarcinoma because it is more compatible with the anatomy of the bile duct. However, other cryoablation applications may indicate a more spherical ice puck. In such scenarios, the expansion chamber can be modified to have a smaller length-to-diameter ratio.

[0118] In some embodiments, the major axis length of the puck may be greater than or equal to 0.5 mm, 2 mm, 4 mm, 6 mm, 8 mm, or 10 mm, or may be a quantity falling within any of the above values. In some embodiments, the minor axis length of the puck may be greater than or equal to 0.5 mm, 2 mm, 4 mm, 6 mm, 8 mm, or 10 mm, or may be a quantity falling within any of the above values.

[0119] Including the grooved tube section, polymer layer, and reinforcing layer of the cryoablation shaft ( Figure 8 )

[0120] Now for reference Figure 8 This diagram illustrates a schematic representation of the top portion of a cryoablation shaft according to various embodiments herein. In various embodiments, the shaft includes an insulating region 105 and an expansion chamber 106. In various embodiments, the insulating region 105 of the shaft 104 includes a supply tube 324 concentrically located within a return tube 326 concentrically located within an insulating shaft 328. The concentric shaft configuration is designed to isolate the working gas circuit and the active vacuum circuit from each other.

[0121] In various embodiments, after exiting handle 102, the high-pressure flow of the working fluid travels downward along supply pipe 324. The high-pressure flow of the working fluid may expand at or downstream of Joule-Thomson orifice 332 and return along the axis in the annular space between supply pipe 324 and return pipe 326.

[0122] In various embodiments, the expansion chamber 106 of shaft 104 includes a supply tube 324 concentrically located within return tube 326. In various embodiments, return tube 326 includes multiple layers.

[0123] In various embodiments, the innermost layer of the return tube is a slotted tube 830, which includes a slot 840 extending at least a portion of the length of the axis 104. The slot 840 is formed in the tube material by any suitable method, such as laser cutting. The slot 840 can be laser-cut into the axis using any suitable pattern to optimize the strength and flexibility of the return tube 326. The material of the slotted tube 830 can be a metal, such as stainless steel, nitinol, or other durable materials. Many different configurations and patterns of the slotted tube 830 are available, and one with the desired flexibility in this application can be selected. In various embodiments, the slotted tube forms the core of the return tube 326.

[0124] In some embodiments, the slotted tube 830 includes a slot that exists only in the expansion chamber 106. In this embodiment, the portion of the slotted tube 830 extending through the insulating region 105 has a solid wall. Figure 8 This embodiment is illustrated by showing a schematic side view of the slotted tube 830 (including the slot 840 in the expansion chamber 106) and a supply tube 324 within the slotted tube 830 shown in dashed lines. In an alternative embodiment, the slotted tube 830 has a slot along its entire length.

[0125] The slotted tube can be configured to be sufficiently flexible to form a curve with a desired radius of curvature. For example, the slotted tube can be flexible enough that the shaft can form a curve with a minimum radius of curvature less than or equal to 30 mm, 20 mm, 10 mm, 5 mm, or 3 mm. The slotted tube 830 can have different levels of flexibility in the expansion chamber and the insulation region 105.

[0126] In various embodiments, a first polymer layer 842 surrounds the slotted portion of the grooved tube 830 to contain working fluid within the shaft 104. In various embodiments, a reinforcing layer 844 surrounds the first polymer layer 842 and is configured to provide additional strength and reinforcement to the first polymer layer 842, thereby reducing the likelihood of any leakage or breakage occurring in the first polymer layer.

[0127] In various embodiments, the first polymer layer 842 may be formed of any suitable polymer, such as polyethylene terephthalate (PET), PTFE, ePTFE, PEEK, polyetherimide (PEI), polyimide (PI), etc. In various embodiments, the reinforcing layer 844 may be a second polymer layer formed of any suitable polymer, such as PET, PTFE, PEEK, polyetherimide (PEI), polyimide (PI), etc. In various embodiments, the reinforcing layer is gas-impermeable. In various embodiments, the reinforcing layer 844 is not impermeable and may comprise woven polymer materials and / or crimped polymer or metallic materials and / or coatings and encapsulating agents.

[0128] In various embodiments, the return tube may include two, three, four, or more polymer layers. In various embodiments, the return tube may include two, three, four, or more total layers.

[0129] exist Figure 8 In one embodiment, the slotted portion of the slotted tube 830 is located within the expansion chamber, and the first polymer layer 842 and the reinforcing layer 844 extend from just within the insulating region 105 to the distal end. In various embodiments, the first polymer layer 842 is bonded to the slotted tube 830 at a first adhesive portion 846 near the proximal end of the expansion chamber 106 and a second adhesive portion 848 near the tip 108 of the shaft 104.

[0130] In various embodiments, the reinforcing layer 844 is bonded to the slotted tube 830 at a first adhesive portion 847 near the proximal end of the expansion chamber 106 and / or a second adhesive portion 849 near the top end 108 of the shaft 104.

[0131] Additional adhesive portions can be placed at any other suitable location along the axis. The adhesive portions can be formed from any suitable material or a combination of materials, such as Vectran, UHMWPE, PEEK, polyimide, or metal wire. Vectran is a synthetic fiber spun from a liquid crystal polymer, which exhibits increased tensile strength at low temperatures, making it suitable for cryoablation systems. In alternative embodiments, adhesive portions 846, 847, 848, and 849 can be formed using alternative techniques such as crimp rings or spin rings, polymer reflow joints, adhesive joints, brazed joints, etc.

[0132] In various embodiments, the winding material of adhesive portions 846, 847, 848, and 849 may also be wound around the polymer layer, reinforcing layer, or both along the entire length of the expansion chamber. The winding layers may have a higher winding pitch at the adhesive location and extend horizontally at a lower pitch along the remainder of the expansion chamber. The winding may extend from the proximal end to the distal end and then reverse direction and extend back in a proximal direction. The number of winding layers may be one, two, three, four, or more.

[0133] In various embodiments, adhesive portions 846, 847, 848, and 849 are configured to increase the burst strength of each layer of the return tube 326.

[0134] In some embodiments, the burst strength of each of the first polymer layer 842 and the reinforcing layer 844 may be greater than or equal to 12.4 MPa, 13.1 MPa, 13.8 MPa, 14.5 MPa, 15.2 MPa, or 41.4 MPa. In some embodiments, the burst strength of each of the first polymer layer 842 and the reinforcing layer may be less than or equal to 41.4 MPa, 20.7 MPa, 19.3 MPa, 17.9 MPa, 16.5 MPa, or 15.2 MPa. In some embodiments, the burst strength may fall within the range of 12.4 MPa to 41.4 MPa, or 13.1 MPa to 27.6 MPa, or 13.8 MPa to 17.9 MPa, or 14.5 MPa to 16.5 MPa, or may be approximately 15.2 MPa.

[0135] In some embodiments, the burst strength of the bonded first polymer layer 842 and reinforcing layer 844 can be greater than or equal to 12.4 MPa, 13.1 MPa, 13.8 MPa, 14.5 MPa, 15.2 MPa, 27.6 MPa, or 41.4 MPa. In some embodiments, the burst strength of the bonded first polymer layer 842 and reinforcing layer 844 can be less than or equal to 41.4 MPa, 20.7 MPa, 19.3 MPa, 17.9 MPa, 16.5 MPa, or 15.2 MPa. In some embodiments, the burst strength of the bonded first polymer layer 842 and reinforcing layer 844 can fall within the range of 12.4 MPa to 41.4 MPa, or 13.1 MPa to 27.6 MPa, or 13.8 MPa to 17.9 MPa, or 14.5 MPa to 16.5 MPa, or can be about 15.2 MPa.

[0136] In some embodiments, the burst strength of each of the adhesive portions 846, 847, 848, and 849 may be greater than or equal to 1.4 MPa, 4.8 MPa, 8.3 MPa, 11.7 MPa, 15.2 MPa, 27.6 MPa, or 41.4 MPa. In some embodiments, the burst strength of each of the adhesive portions may be less than or equal to 41.4 MPa, 34.8 MPa, 28.3 MPa, 21.7 MPa, or 15.2 MPa. In some embodiments, the burst strength of each of the adhesive portions may fall within the range of 1.4 MPa to 41.4 MPa, or 4.8 MPa to 34.8 MPa, or 8.3 MPa to 28.3 MPa, or 11.7 MPa to 21.7 MPa, or may be approximately 15.2 MPa.

[0137] In some embodiments, all adhesive portions 846, 847, 848, and 849 may have the same burst strength. Alternatively, some of the adhesive portions may have a higher burst strength than the others. For example, proximal adhesive portions 846 and 847 may have a lower burst strength than distal adhesive portions 848 and 849.

[0138] In various embodiments, the return tube 326 can be configured to be sufficiently flexible to form a curve with a desired radius of curvature. For example, the return tube can be sufficiently flexible such that the shaft can form a curve with a minimum radius of curvature less than or equal to 30 mm, 20 mm, 10 mm, 5 mm, or 3 mm.

[0139] The slotted section can extend the entire length of the return pipe.

[0140] Figure 8 The illustration shows a slotted tube 830 comprising a slot only within the expansion chamber 106, but in an alternative embodiment, the slotted tube 830 has a slot extending along its entire length. In this alternative embodiment, the first polymer layer 842 and the reinforcing layer 844 also extend along the entire length of the return tube 326. A reinforcing winding layer, such as a Victora material, may also extend along the entire length of the return tube. It may be desirable to have a slot along the entire length of the return tube to achieve the desired level of flexibility along the return tube.

[0141] Including the slotted tube section and the gradient braided cryoablation shaft ( Figure 9 )

[0142] Now for reference Figure 9 This diagram illustrates a portion of a cryoablation shaft according to various embodiments thereof. In various embodiments, the shaft includes an insulating region 105 and an expansion chamber 106. In various embodiments, the insulating region 105 of the shaft 104 includes a supply tube 324 located within a return tube 326. Figure 9 The return tube 326 includes multiple layers.

[0143] The innermost layer of the return tube 326 is a slotted tube 830, which can be constructed using the options and details described herein. The slotted tube 830 is surrounded by a polymer layer 956, which is concentrically surrounded by a reinforcing gradient braided layer 940.

[0144] In various embodiments, the gradient braided layer 940 includes regions with different braid densities, such that the density increases towards the distal end of the device. A first braided region 958 is present in the insulating region and has the lowest density. A second braided region 960 overlaps with the insulating region 105 and the expansion chamber 106 and has a higher density than the first braided region 958. A third braided region 962 has the highest density and is present in the expansion region. The return tube may include one, two, three, or more braided layers.

[0145] In various embodiments, the polymer layer 956 is configured to contain the working fluid in the return tube and prevent the working fluid from escaping radially through slots in the slotted tube. The polymer layer may be constructed of the options and materials discussed herein with respect to the first polymer layer. In some embodiments, the expansion chamber 106 may include an additional braided layer (not shown in this view) between the slotted tube 830 and the polymer layer 956. The additional braided layer is configured to prevent friction between the polymer layer 956 and the slotted tube 830.

[0146] Examples of braiding materials, braided element diameters, braiding density zones, coils, and burst strength.

[0147] Braided tubing is used in a variety of medical applications. Braided reinforced tubing can improve the functional properties of medical devices, such as strength, stiffness, burst pressure resistance, torque transmission, and kink resistance. These characteristics allow cryoablation shafts to pass through tortuous sections of a patient's anatomy, such as the bile duct. Design considerations such as braid pattern, warp and weft density (ppi), material, wire size, wire size / shape, and plastic stiffness can significantly impact device performance.

[0148] The braided portion of the shaft can be formed from any suitable material or a combination of materials, such as metals (e.g., nitinol, stainless steel, tungsten, MP35N, or other such materials), polymers (e.g., PET, Kevlar, carbon fiber, Victor, or other such materials), etc. The braided material is formed by weaving metal or fiber filaments in a braided pattern. In various embodiments, the cross-section of the filaments is circular; however, other cross-sectional shapes are also possible (e.g., flat, star-shaped, triangular). In some embodiments, the diameter of the filaments can be greater than or equal to 0.01 mm, 0.1 mm, 0.2 mm, 0.3 mm, or 0.5 mm. In some embodiments, the diameter of the filaments can be less than or equal to 2 mm, 1.6 mm, 1.2 mm, 0.8 mm, or 0.5 mm. In some embodiments, the diameter of the filaments can fall within the range of 0.01 mm to 2.00 mm, or 0.1 mm to 1.6 mm, or 0.2 mm to 1.2 mm, or 0.3 mm to 0.8 mm, or can be about 0.5 mm.

[0149] In various embodiments, the density of the braided portion can be varied, with a higher density braid providing greater radial strength and stiffness, and a lower density braid providing greater flexibility. The shaft may include multiple braids with different material properties. In various embodiments, the shaft may include a lightweight braid (e.g., with a relatively low braid density) between the return tube 326 and the polymer layer 956. As mentioned above, the lightweight braid can provide limited structural support but can prevent excessive friction between the slotted return tube 326 and the polymer layer 956.

[0150] In various embodiments, the density of the braided material can increase from the base of the shaft 104 to the tip 108 of the shaft. In the event of a device failure, this configuration increases the likelihood of failure occurring closer to the base of the shaft. For patient safety outcomes, this failure mode is generally more desirable than failure occurring closer to the tip 108 of the shaft.

[0151] In various embodiments, a first gradient braided region 958 spans the insulation region 105 of the shaft 104 (starting from the location where the shaft connects to the handle 102 and terminating at or before the expansion chamber 106). In various embodiments, the gradient braided portion 958 may have a first burst strength. The first burst strength may be constant along the insulation region of the shaft. Alternatively, the first burst strength of the gradient braided portion 958 may increase from the base of the shaft to the expansion chamber. In various embodiments, the gradient braided portion 958 may have a first braid density. The first braid density may be constant along the insulation region of the shaft. Alternatively, the first braid density of the gradient braided portion 958 may increase from the base of the shaft to the expansion chamber.

[0152] In some embodiments, the minimum burst strength of the gradient braided portion 958 may be less than or equal to 20.7 MPa, 13.8 MPa, 6.9 MPa, 5.5 MPa, 4.1 MPa, 2.8 MPa, 1.4 MPa, or 0.7 MPa, or may be an amount falling within the range of any of the aforementioned values. In some embodiments, the maximum burst strength of the gradient braided portion 958 may be greater than or equal to 0.7 MPa, 2.0 MPa, 3.4 MPa, 4.8 MPa, 6.2 MPa, 6.9 MPa, 13.8 MPa, or 20.7 MPa, or may be an amount falling within the range of any of the aforementioned values.

[0153] In various embodiments, the second braided portion 960 spans the expansion chamber 106 of the shaft 104. In some embodiments, the second braided portion 960 may begin at the start of the expansion chamber and terminate at or near the tip 108 of the shaft. Alternatively, the second braided portion 960 may begin toward the distal end of the insulating region 105 of the shaft (e.g., Figure 9(as shown), and terminates at or near the top 108 of the shaft. In some embodiments, the second braided portion 960 is a continuation of the first braided portion 958. Alternatively, the second braided portion 960 may be made of elements physically separate from the elements of the first braided region 958.

[0154] In various embodiments, the second braided portion 960 may have a second burst strength. The second burst strength may be constant along the length of the first braided layer. Alternatively, the second burst strength of the second braided portion 960 may increase along the length of the first braided layer (from the end of the insulating region 105 to the top 108). In various embodiments, the second braided portion 960 may have a second braid density. The second braid density may be constant along the length of the second braided portion. Alternatively, the second braid density of the second braided portion 960 may increase along the length of the second braided portion.

[0155] In some embodiments, the burst strength of the second braided portion 960 may be greater than or equal to 10.3 MPa, 12.9 MPa, 15.5 MPa, 18.1 MPa, 20.7 MPa, or 41.4 MPa. In some embodiments, the burst strength of the second braided portion 960 may be less than or equal to 34.5 MPa, 31.0 MPa, 27.6 MPa, 24.1 MPa, or 20.7 MPa. In some embodiments, the burst strength of the second braided portion 960 may fall within the range of 10.3 MPa to 34.5 MPa, or 12.4 MPa to 31.0 MPa, or 15.5 MPa to 27.6 MPa, or 17.9 MPa to 34.5 MPa, or may be approximately 20.7 MPa.

[0156] In various embodiments, the third braided region 962 spans the expansion chamber 106 of the shaft 104. In some embodiments, the third braided region 962 may begin at the start of the expansion chamber and terminate at or near the top of the shaft 108.

[0157] In various embodiments, the third braided region 962 may have a third burst strength. The third burst strength may be constant along the length of the third braided region. Alternatively, the burst strength of the third braided region 962 may increase along the length of the third braided region. In various embodiments, the third braided region 962 may have a third braid density. The braid density may be constant along the length of the third braided region. Alternatively, the braid density of the third braided region 962 may increase along the length of the first braided layer.

[0158] In some embodiments, the explosive strength of the third braided region 962 may be greater than or equal to 10.3 MPa, 12.9 MPa, 15.5 MPa, 18.1 MPa, or 20.7 MPa. In some embodiments, the explosive strength of the third braided region 962 may be less than or equal to 34.5 MPa, 31.0 MPa, 27.6 MPa, 24.1 MPa, or 20.7 MPa. In some embodiments, the explosive strength of the third braided region 962 may fall within the range of 10.3 MPa to 34.5 MPa, or 12.4 MPa to 31.0 MPa, or 15.5 MPa to 27.6 MPa, or 17.9 MPa to 24.1 MPa, or may be approximately 20.7 MPa.

[0159] In alternative embodiments, any or all of the gradient braided regions 958, 960, 962 may be formed of coils. As defined herein, a coil is a filament of material wound around a shaft. Similar to the braided materials described in detail above, the filament may be selected to have a suitable material and cross-sectional shape, including circular, rectangular, or other shapes. Regions may include coils with different densities, radial strengths, stiffness, and flexibility. Coils may be single-layered or multi-layered. In some embodiments, multi-layered coils may have alternating winding directions (e.g., a first layer wound clockwise and a second layer wound counterclockwise). In various embodiments, the coil pitch may be varied to optimize shaft properties such as flexibility, burst strength, etc. For example, a tighter coil pitch may increase the burst strength of the shaft, while a looser coil pitch may increase the flexibility of the shaft. In various embodiments, the pitch of the coil material may increase from the base of the shaft 104 to the tip 108 of the shaft.

[0160] Transition between woven areas

[0161] In some embodiments, the transition between the first, second, and third braided portions is a density transition of the same physical braided elements, such that a braided region is a continuation of an adjacent braided region. Alternatively, a braided portion may be made of elements that are physically separate from the elements of the adjacent braided regions.

[0162] Composite shaft ( Figure 10 )

[0163] Now for reference Figure 10 This diagram illustrates a portion of a cryoablation shaft according to various embodiments thereof. In various embodiments, the expansion chamber 106 of the shaft 104 includes a supply tube 324 concentrically located within a composite return tube 1064. In various embodiments, the return tube may be a composite shaft. In various embodiments, the composite return tube 1064 is formed of one or more discrete layers. One possible return tube layer is... Figure 10 The braided layer 1066 shown is illustrated.

[0164] In various embodiments, the composite return tube 1064 may be formed of one or more polymer layers and / or braided layers as described in detail herein. After forming the discrete layers, the composite shaft may be heated to a temperature that causes the discrete layers to bond together, thereby forming a single composite layer. In some embodiments, some discrete layers may contribute to the radial strength of the expansion chamber, and other discrete layers may contribute to the gas containment capacity of the expansion chamber. In such embodiments, radial strength and gas containment may be achieved by a single composite layer. Such a configuration can enhance the tunability of the expansion chamber material properties while reducing the diameter of the expansion chamber.

[0165] In some embodiments, an additional braided layer 1066 may be provided on the remainder of the composite return tube 1064. The additional braided layer is selected to have braided properties that enhance the radial strength of the expansion chamber 106.

[0166] Example of a remote accessory ( Figure 10 )

[0167] In various embodiments, a plug 1068 and one or more fittings 1070 may be used to contain the working fluid at the tip 108 of the shaft. In various embodiments, the fittings 1070 and / or the plug 1068 may be made of a material or a combination of materials compatible with the composite return tube 1064 and / or the braided layer 1066 to enhance the seal of the shaft 104. In various embodiments, the fittings 1070 and / or the plug 1068 may be made of a material or a combination of materials that are robust enough to enhance the burst strength of the expansion chamber.

[0168] In various embodiments, the plug 1068 includes a ridge 1072. The ridge 1072 enhances the mechanical strength of the adhesive joint 1070 by providing additional structural support to the adhesive portion to resist pressure within the expansion chamber.

[0169] Leak-then-break seal / Engineering seal

[0170] During cryoablation procedures, some failure modes pose a lesser impact than others. For example, a leak near the proximal end of the shaft poses a far less risk to the patient than a leak near the tip of the shaft or a shaft bursting. In various embodiments, the cryoablation system can be designed to rapidly detect system failures and automatically shut down the system.

[0171] In various embodiments, it is desirable to avoid blockages in the working fluid return path. Such blockages could cause shaft 104 to burst, resulting in adverse patient outcomes. In some embodiments, it may be desirable for the shaft to leak before bursting. If the working fluid is blocked in the return path, pressure will accumulate in the return path until the shaft eventually bursts. For example, under normal operating conditions, the operating pressure of the returning working fluid may be in the range of about 150 psi to 200 psi, but in a blocked scenario, the pressure can rapidly reach values ​​greater than 1500 psi (e.g., about 1800 psi).

[0172] Return to reference Figure 8 In various embodiments, the adhesive portion 847 between the reinforcing layer 844 and the slotted tube 830 may be designed to leak at a specific leakage threshold pressure, which is significantly lower than the burst pressure of the shaft 104. In some embodiments, the leakage threshold pressure may be greater than or equal to 200 psi, 300 psi, 400 psi, or 500 psi. In some embodiments, the leakage threshold pressure may be less than or equal to 1000 psi, 875 psi, 750 psi, 625 psi, or 500 psi. In some embodiments, the leakage threshold pressure may fall within the range of 200 psi to 1000 psi, or 200 psi to 875 psi, or 300 psi to 750 psi, or 400 psi to 625 psi, or may be approximately 500 psi.

[0173] When the adhesive portion 747 leaks, the working fluid will overflow from the reinforcing layer 844 into the space between the slotted tube and the insulating shaft. In various embodiments, the adhesive portion 847 is contained within the insulating portion 105 of the shaft 104. Therefore, the leaked working fluid is contained in the vacuum circuit of the shaft between the slotted tube and the insulating shaft. In various embodiments, the cryoablation system is configured to shut down when the presence of working fluid in the vacuum circuit is detected.

[0174] In various embodiments, seals designed to have sufficiently low burst strength (e.g., significantly lower than the burst strength of the shaft) can be placed at other locations on the shaft where leakage is preferable to bursting or other failure modes. Generally, leakage on the shaft closer to handle 102 has less impact than leakage on the shaft closer to tip 108. This is because leakage closer to handle is detected more quickly and is less likely to penetrate patient tissue. In various embodiments, the shaft may include one, two, three, four, or more engineered seals placed at various locations along the shaft.

[0175] In various embodiments, the adhesive portion 848 between the first polymer layer 842 and the slotted tube 830 has a second leakage threshold pressure, which is significantly higher than the leakage threshold pressure of the adhesive portion 847. In some embodiments, the second leakage threshold pressure may be greater than or equal to 1600 psi, 1750 psi, 1900 psi, 2050 psi, or 2200 psi. In some embodiments, the second leakage threshold pressure may be less than or equal to 2800 psi, 2650 psi, 2500 psi, 2350 psi, or 2200 psi. In some embodiments, the second leakage threshold pressure may fall within the range of 1600 psi to 2800 psi, or 1750 psi to 2650 psi, or 1900 psi to 2500 psi, or 2050 psi to 2350 psi, or may be approximately 2200 psi.

[0176] Use pressure sensors to detect leaks.

[0177] In various embodiments, the cryoablation system can be designed to quickly detect system failures and automatically shut down the system. In various embodiments, the cryoablation system is configured to detect leaks in the first polymer layer 842 and / or the reinforcing layer 844. In various embodiments, a vacuum is operated in the insulating portion 105 of the shaft 104 located between the slotted tube 830 and the insulating shaft 328. In the event of a leak of working fluid through the first polymer layer 842 or the reinforcing layer 844 (e.g., at the adhesive portions 846 and 847), it breaks through the vacuum region between the slotted tube and the insulating shaft. Such an event causes a rapid loss of vacuum pressure, which can be detected at a pressure sensor at the cryoablation system console (as will be described in more detail herein).

[0178] Explosion valve embodiment

[0179] In alternative embodiments, the cryoablation system may include one or more burst valves in any of the shaft 104, handle 102, and console. For example, the cryoablation system may include one, two, three, four, or more burst valves at multiple locations along the entire length of the shaft and / or handle. The burst valves are configured to provide a flow barrier that opens or bursts to release pressure when the pressure in the probe becomes dangerously high. In various embodiments, one or more burst valves are replaceable after each shaft failure event.

[0180] The burst valve can be configured to rupture at a leakage threshold pressure (which may be the same as or different from the leakage threshold pressure at the adhesive section 847, as long as it is sufficiently below the burst strength of the shaft). The burst valve can be configured to send a signal to the control console, or the control console can detect a drop in vacuum pressure in the vacuum circuit. The control console can then automatically shut off the flow of the working gas and the precooling gas to prevent harm to the patient or the system. Other suitable active or passive mechanical features can be used instead of the burst valve.

[0181] In various embodiments, the handle 102 may include one or more burst valves (or other equivalent mechanical components). In various embodiments, the one or more burst valves are configured to leak in the working gas fluid circuit, the precooling fluid circuit, or both.

[0182] In a particular embodiment, the insulating portion 105 of the handle 102 or flexible shaft may include a T-shaped chamber having a T-shaped portion extending radially from the return tube toward the insulating shaft, perpendicular to the axis of the return tube. At the end of the T-shaped portion, a burst valve is present. If abnormal pressure accumulates in the return tube, the burst valve can rupture at a leakage threshold pressure, such as the leakage threshold pressure described herein, to release the pressure.

[0183] Laser-cut window

[0184] In various embodiments, the innermost layer of the return tube may contain one or more laser-cut windows covered with a polymer layer. If abnormal pressure accumulates in the return tube, the polymer layer covering the laser-cut windows can be engineered to leak at a leakage threshold pressure, such as the leakage threshold pressure described herein. For example, the laser-cut windows can be sequentially cut in the return tube through which the working gas exhaust flow occurs.

[0185] Protective lining

[0186] In various embodiments, certain portions of the shaft may include a protective liner. In some embodiments, the inner surface of the insulating shaft 328 may be coated with a protective liner. The protective liner may coat certain portions of the insulating shaft or the entire circumference and length of the insulating shaft. Alternatively or additionally, the inner surface of the return tube 326 may be coated with a protective liner. The protective liner may coat certain portions of the return tube or the entire radius and length of the return tube. The protective liner may be formed of a metal liner, a sputtered coating, a sputter-coated metal liner, etc. In various embodiments, the protective liner is configured to increase the burst strength of the return tube and / or the insulating shaft and reduce the likelihood of device failure. A thin coating may have minimal impact on flexibility.

[0187] Diagnostic tools for measuring hockey formation

[0188] In various embodiments, it is desirable to assess and monitor ice ball formation throughout the duration of the cryoablation procedure. For example, ice ball formation provides an indication of whether the axis 104 (and particularly the expansion chamber 106) is correctly positioned relative to the patient's tissue. If the axis is improperly positioned, the ice ball may not form properly. Monitoring ice ball formation can also be used to verify that the ice adequately covers the tissue and / or tumor and has adequate margins, while protecting critical structures from cryoablation. Furthermore, the ability to monitor time points when the ice ball size stabilizes facilitates the application of accurate and consistent ice ball residence times. These benefits maximize the therapeutic value of cryoablation while minimizing complications.

[0189] In various embodiments, the cryoablation system 100 may include one or more diagnostic tools for measuring the size of the ice ball. In some embodiments, conventional medical imaging, such as computed tomography (or CT), percutaneous ultrasound (TUS), or MRI imaging depending on the application, may be used to monitor ice ball formation for observation as the cryoablation progresses within a tumor or tissue.

[0190] electrode

[0191] In various embodiments, the cryoablation system 100 may include one or more electrodes for measuring puck size. In some embodiments, puck size can be measured by receiving impedance from at least one electrode along axis 104. In various embodiments, axis 104 may include an electrode arrangement. The electrode arrangement includes at least one electrode, but may also include two, three, four, or more electrodes. The electrode arrangement may be positioned at any suitable location along the axis, such as adjacent to expansion chamber 106 or at the top end 108 of the axis. Alternatively, the electrode arrangement may include multiple electrodes positioned along different portions of axis 104. For example, electrodes may be positioned along the axis from handle to top end.

[0192] In various embodiments, the electrode arrangement is configured to engage the ice puck as it forms on the expansion chamber during cryoablation. The progression of ice puck formation results in sensed impedance changes. In various embodiments, the cryoablation system can receive impedance measurements from at least one electrode in the electrode arrangement. Based on the impedance measurements, one or more physical properties of the ice puck can be determined. In various embodiments, one or more physical properties may include at least one of ice puck shape, ice puck size, and ice puck temperature. In particular embodiments, the impedance measurements may be used to track the growth of one or more isotherms of the ice puck (e.g.,...). Figure 7 (As shown). By using an electrode assembly to track the evolving physical properties of the ice puck, the operator can assess the efficacy of cryoablation in real time and make adjustments as needed (e.g., axis position, cryoablation duration).

[0193] By positioning electrodes along the length of the flexible axis and the expansion chamber, the system can monitor the long axis of the ice puck.

[0194] In some embodiments, the electrode assembly (or another suitable heating technique) can also be used to apply heat to the tissue surrounding the expansion chamber 106 or the tip 108. Such heat application reduces the likelihood of cell seeding occurring when the device is withdrawn from the patient's tissue.

[0195] Thermocouple device

[0196] In various embodiments, the cryoablation system may include one or more thermocouple devices. For example, the cryoablation system may include a thermocouple at the tip 108. The thermocouple may be brazed to the tip, glued, or otherwise adhered to the tip using conductive epoxy, or connected to the tip by any other suitable means. The cryoablation system may include additional thermocouple devices along the length of axis 104 and / or in handle 102. Thermocouple devices may be linked to temperature sensing components in the console (in... Figures 11 to 12 (See detailed description below). Temperature sensing components may include many additional component modules, such as resistors, diodes, and thermocouples.

[0197] One or more thermocouple devices positioned at or near the top of the expansion chamber and / or shaft enable temperature measurement of the target nerve or tissue. Such temperature measurement allows the operator to track the progress of the cryoablation procedure. In various embodiments, one or more thermocouple devices positioned in the handle allow the operator to observe the temperature of the precooling fluid and the working fluid. Such temperature measurement enables the operator to ensure that the precooling fluid and the working fluid are sufficiently cold before initiating the cryoablation procedure.

[0198] Overview of cryoablation systems ( Figure 11 )

[0199] Now for reference Figure 11 The diagram illustrates a cryoablation system according to various embodiments thereof. The cryoablation system may include a console operatively connected to a cryoablation catheter and one or more supply sources.

[0200] In one embodiment, the first supply source may be argon or any other suitable cooling fluid (e.g., nitrogen, air, argon, krypton, xenon, N2O, CO2, CF4). The argon supply source is used to supply both the working fluid and the precooling fluid to the cryoablation catheter. In an alternative embodiment, the system may include separate fluid reservoir supply sources or tanks for the working fluid circuit and the precooling circuit of the cryoablation catheter.

[0201] In various embodiments, the second supply source can be helium or any other heating fluid (e.g., hydrogen). In some embodiments, the heating fluid can be used as the working fluid. In this case, the high-pressure flow of the working fluid can be such that expansion via the Joule-Thomson orifice 332 can cause an increase in the temperature of the primary fluid, which correspondingly results in heating of the tissue surrounding the distal working fluid. Such embodiments can be used to thaw frozen tissue.

[0202] The third power source can be any suitable power source configured to power the console and cryoablation catheter.

[0203] console ( Figure 12 )

[0204] Now for reference Figure 12 A schematic diagram of a console for a cryoablation system according to various embodiments herein is shown. Figure 12 Elements of various embodiments of the console described herein are illustrated. However, it should be understood that some embodiments may include... Figure 12 Additional components beyond those shown. Additionally, some embodiments may lack... Figure 12 Some of the components shown are illustrated. In various embodiments, the console may be electrically and fluidly connected to the cryoablation conduit and may include one or more fluid reservoirs, coolant recovery reservoirs, valves, conduits, connectors, heaters, temperature sensors, pressure sensors, flow sensors, power supplies, computing devices, displays, and user input controls (e.g., keyboards, buttons). In various embodiments, the console includes internal and external interfaces. System boundaries separate the internal and external interfaces and provide connectivity to the console.

[0205] In various embodiments, the console includes electrical and software subsystems. The electrical and software subsystems include one or more computing devices. The computing devices may include a microprocessor that communicates with memory via a bidirectional data bus. The memory may include read-only memory (ROM) or random access memory (RAM) for program storage and RAM for data storage. The electrical and software subsystems may be electrically connected to each of the other control subsystems to supply power to the subsystems and to transmit signals between them.

[0206] The electrical and software subsystems can also be electrically connected to the cryoablation catheter and can be configured to control the operating parameters of the cryoablation catheter. In one embodiment, the electrical and software subsystems can be programmed to control various system components, such as one or more valves, to operate according to a work cycle that includes opening and closing one or more valves to regulate the flow of working fluid through the cryoablation catheter.

[0207] In various embodiments, the software subsystem is configured to receive firmware updates and output a data log regarding the status of the cryoablation system. In various embodiments, the electrical subsystem is configured to receive power from a power source and output an audible alarm regarding the status of the cryoablation system.

[0208] In various embodiments, the console includes a gas-to-electricity subsystem. This subsystem may be in fluid communication with an argon and helium fluid supply source. Fluids may circulate between the supply source and the cryoablation conduit via the gas-to-electricity subsystem. Fluids may be discharged from the cryoablation system to the surrounding environment via the gas-to-electricity subsystem. Alternatively, the fluids may be recovered and reused (e.g., by pumping the recovered fluids back to their respective supply sources). In such embodiments, the cryoablation system is effectively a closed-loop system, and no fresh argon and helium supply is required for each use. The gas-to-electricity subsystem may include one or more control gas solenoids to control the flow from the gas supply source. The gas-to-electricity subsystem may be configured to measure the pressure of the system fluids, drive and detect freezing and / or thawing cycles during the cryoablation procedure, and provide control for all system fans (not shown).

[0209] In various embodiments, the console includes a vacuum subsystem. The vacuum subsystem may be in fluid communication with an internal gas interface. The vacuum subsystem is configured to provide a vacuum to the cryoablation catheter via a vacuum connection. In various embodiments, the vacuum subsystem is electrically connected to an electrical subsystem to power a vacuum pump. The vacuum subsystem may also communicate with one or more flow and / or pressure sensors to measure vacuum pressure.

[0210] In various embodiments, the console includes a touchscreen display configured to provide information about the cryoablation system (e.g., operator instructions, status of the cryoablation process) and / or receive input from the operator (e.g., desired ablation time). The touchscreen is configured to display information to the user via visual alarms and to receive feedback and / or commands from the operator. Operator feedback can be collected in any number of suitable ways, such as a touchscreen, keyboard, microphone (for receiving voice commands), etc. In addition to or as an alternative to a touchscreen display, the console may include any other suitable user interface, such as one or more buttons, dials, indicator lights, etc.

[0211] In various embodiments, the console includes a rack and / or trolley frame. In various embodiments, the rack and / or trolley frame is configured to mount a touchscreen display, a vacuum subsystem, a gas subsystem, and an electrical subsystem to the console. In some embodiments, the cryoablation system is mobile, and the trolley frame includes wheels or the like for transporting the system. In some embodiments, the cryoablation system may include one or more accessories (e.g., an imaging system, additional parts, etc.) that may be stacked on the rack and / or trolley frame.

[0212] Redundant security features

[0213] In various embodiments, the cryoablation system may include one or more sensors (e.g., pressure sensors, temperature sensors, flow sensors) throughout the console and / or cryoablation catheter, configured to detect changes in gas flow or vacuum pressure, such as in the event of a leak in any part of the cryoablation system. For example, the console may include one or more multi-stage rupture components (e.g., rupture discs, valves, etc.) integrated into the console and in fluid communication with the working fluid circuit and the precooling fluid circuit. The console is configured to detect a rupture in any of the multi-stage rupture components. Upon detection of a rupture, the console may be configured to automatically shut down the cryoablation system to minimize harm to the system and / or the patient, such as shutting off the supply of working gas, precooling gas, vacuum pump, or more of these.

[0214] In various embodiments, the console is configured to control the extent of the cryoablation procedure (e.g., the size of the ice ball formed in the expansion chamber). For example, the console is configured to collect feedback information from one or more sensors (e.g., electrodes, thermocouple devices) integrated into the cryoablation catheter. Based on the information collected from the one or more sensors, the console is configured to maintain or change cryoablation operating parameters (e.g., cryoablation duration) to improve surgical outcomes.

[0215] In some embodiments, the console enables automated CT scan integration. CT scan integration can enable computer-aided catheter placement and / or puck size determination.

[0216] Fluid connector locking configuration

[0217] In various embodiments, the fluid connectors at the gas subsystem of the console are configured to ensure the operator connects the correct supply gas. In one embodiment, each fluid connector at the gas subsystem may include electronic components. When the correct supply gas is connected to the gas subsystem, the electrical components and / or one or more pressure sensors send a signal to the processor to verify that the connection is complete and correct. Alternatively, when an incorrect supply source is connected to the gas subsystem (e.g., when an argon supply gas is connected to a helium connection), no signal is sent to the processor. In various embodiments, the console will not allow the cryoablation procedure to begin until the correct fluid connection is verified at the processor. In an alternative embodiment, physical measurements of each loop of the gas subsystem are measured and sent to the processor to verify that the connection is correct and complete.

[0218] In one alternative embodiment, each of the gas supply connectors in the gas subsystem may have a different size, and each gas supply source may be configured to connect only to a connector of the appropriate size. In another embodiment, each of the gas supply connectors in the gas subsystem may include a sniffer connected in series with the gas connection conduit. Each sniffer is configured to detect the type of gas (e.g., argon or helium) connected to its respective connector, and the cryoablation procedure can only begin when each sniffer detects the correct gas type. Such connectors make it impossible for the operator to accidentally attach an incorrect gas supply source.

[0219] Redundancy safety features – program

[0220] Switch the vacuum pump to the working gas circuit before the procedure.

[0221] In various embodiments, the console is configured to perform one or more safety procedures to enhance the safety of cryoablation procedures. For example, the console may be configured to perform a vacuum check procedure to ensure the integrity of the probe before performing the cryoablation procedure.

[0222] To perform a vacuum check procedure, during catheter placement to the desired location or after the cryoablation catheter is in place, the console is configured to switch the vacuum pump from purging the insulating sleeve to purging the working gas channel. This is achieved by closing the working gas vent, closing the working gas supply, evacuating the working gas circuit, and using a pressure sensor or flow sensor to check for any changes or deviations in the vacuum pressure (e.g., a decrease in vacuum pressure). A stable vacuum pressure indicates no leaks in the working gas channel. Changes or deviations in the vacuum pressure indicate leaks in the working gas channel. Performing a vacuum check procedure ensures the airtightness of the flexible catheter after placement to the treatment location and before cryoablation. This procedure reduces the risk of any working fluid leakage into the patient's tissue or the surrounding environment.

[0223] The connection between the gas subsystem and the vacuum subsystem can be used to connect a vacuum pump to the working gas circuit to enable this safety procedure. In an alternative embodiment, the user can reconfigure the system to measure the working gas circuit relative to the isolated vacuum circuit.

[0224] The pressurization process connected to the gas supply source

[0225] After checking the working gas passage for seals, the console can connect the working gas supply source to the working fluid loop. For example, an operator can initiate a pressurization procedure by interacting with the console (e.g., via a touchscreen), and the gas loop can switch gas connections without operator intervention. Alternatively, the operator can manually connect the working gas supply source to the working fluid loop. Connecting the working gas supply source to the working fluid loop can potentially lead to leaks, especially if very high-pressure gas is introduced into the system immediately. To mitigate the risk of leaks, the console is configured to use a pressurization process. The console is initially configured to introduce the working gas at a pressure significantly lower than the operating pressure (approximately 600 psi or less). The console or operator is then configured to measure the pressure in the working gas passage, which will display the peak value at the initial gas introduction using a pressure sensor in the console. If there are no leaks in the system, the pressure sensed at the pressure sensor will stabilize over time. After the pressure stabilizes, the console or operator is then configured to gradually increase the gas pressure until the operating pressure is reached (e.g., approximately 1800 psi). Each time the pressure is increased, the console or operator waits for the gas pressure to stabilize. Identifying a period of pressure stabilization before introducing a higher-pressure gas flow helps ensure there are no leaks in the system. A pressurization procedure can replace or be combined with any of the other safety devices and procedures described herein.

[0226] The pressurization process can also be used to introduce gas into a precooled fluid circuit.

[0227] Vacuum chamber integrity check

[0228] In various embodiments, the console can be configured to check the integrity of the vacuum circuit before initiating the cryoablation procedure. When the vacuum pump is started, a vacuum is drawn into the insulated portion of the shaft. In various embodiments, the vacuum may take several minutes to reach the desired pressure and stability. In various embodiments, a pressure sensor is present at some point in the vacuum circuit (either in the console or the cryoablation catheter). The pressure sensor may be electrically connected to the console. In various embodiments, the console is configured to use the pressure sensor to measure the vacuum pressure in the vacuum circuit.

[0229] In one example, the console is configured to monitor the vacuum circuit pressure over a set time period. During this time period, the console is configured to shut off the vacuum. If the pressure increases at a rate exceeding a threshold, the console detects a leak in the vacuum circuit. If the pressure remains constant or decays slowly enough, the console indicates that the vacuum is functioning correctly. After each of the safety checks is performed, the console can allow cryoablation to begin.

[0230] Shaft integrity test procedure ( Figures 13 to 16 )

[0231] In various embodiments, it is desirable to ensure that the cryoablation shaft is a closed system (leak-free) before pumping pressurized working and / or precooled gas through shaft 104. Once the shaft has been inserted into the patient, it is not desirable to use positive pressure to test for leaks in the cryoablation system, because in the event of a leak, pressurized gas may flow through the system and enter the patient's body.

[0232] To avoid such risks, a shaft integrity test can be performed before the pressurized working gas and precooled gas flow through shaft 104. In various embodiments, the shaft integrity test utilizes the shaft's ability to achieve and maintain a vacuum between supply tube 324 and return tube 326 to determine if the probe is a closed system. If the shaft fails to achieve and maintain a sufficiently low vacuum level, it is determined that the shaft is damaged. If the shaft is inside the patient and a leak occurs during the shaft integrity test, fluid from the patient may flow into the shaft. Although such a scenario could damage the cryoablation system, it is unlikely to cause harm to the patient. Systems and methods for performing shaft integrity tests are described in further detail herein.

[0233] Test equipment ( Figure 13 )

[0234] Now for reference Figure 13This document illustrates a schematic diagram of a test apparatus for performing shaft integrity testing according to various embodiments thereof. To perform the shaft integrity test, the cryoablation system is configured to switch the vacuum source 114 between emptying the vacuum circuit (e.g., the space between return pipe 326 and the insulated shaft 328) and emptying the working gas return path (e.g., the space between supply pipe 324 and return pipe 326). In some embodiments, the test apparatus is... Figure 12 A portion of the console shown and described.

[0235] In various embodiments, the test apparatus 1300 may include a vacuum source 114. The vacuum source may be a vacuum pump, etc. In some embodiments, the vacuum source 114 is an active vacuum. For example, the vacuum source 114 may be a vacuum pump, etc. During normal operation, the vacuum source 114 is operatively connected to a vacuum chamber. However, when performing a shaft integrity test, the vacuum source is switched to be operatively connected to a working gas circuit. In an alternative configuration, the cryoablation system 100 may include a first vacuum source for purging the vacuum circuit and a second vacuum source for purging the working return path.

[0236] A vacuum source can be connected to any part of the working gas circuit to perform shaft integrity testing. In various embodiments, the vacuum source is switched to be connected to the gas return path. In various embodiments, the vacuum source is switched to be connected to the supply pipe. The gas return path and the supply pipe are components of the working gas circuit and are in fluid communication with each other.

[0237] In various embodiments, the test apparatus 1300 may include a vacuum pressure sensor 1304. In various embodiments, the pressure sensor is configured to monitor the pressure in the working gas return path and / or the vacuum loop. The pressure sensor 1304 may be any suitable type of pressure sensor, such as a gauge pressure sensor. In some embodiments, the test apparatus may include two, three, or more pressure sensors configured to monitor pressure at various locations or sites within the cryoablation system.

[0238] In various embodiments, the test apparatus 1300 may include a valve 1306. Valve 1306 may be a three-way valve. In various embodiments, valve 1306 may be actuated to switch between a first position connecting a vacuum source to a vacuum chamber and a second position connecting a vacuum source to a working gas circuit. In various embodiments, the test apparatus 1300 may also include a user interface (such as a touchscreen display on a console) that allows the operator of the cryoablation system to selectively actuate valve 1306 via the user interface to switch between the first and second positions.

[0239] In various embodiments, the test apparatus 1300 may include a probe insulating manifold 1310. In various embodiments, the probe insulating manifold 1310 may include one or more mating features (e.g., O-rings) and is configured to be hermetically connected to the cryoablation probe. In various embodiments, when the cryoablation probe is connected to the probe insulating manifold 1310, the vacuum chamber is in fluid communication with the vacuum source 114. Therefore, when the vacuum source 114 is energized and the valve 1306 is switched to its first position, the vacuum source is configured to evacuate the vacuum chamber, thereby providing insulation for the cryoablation shaft 104.

[0240] In various embodiments, the test apparatus 1300 may include an integrity test manifold 1312. In various embodiments, the integrity test manifold 1312 may include one or more mating features (e.g., O-rings) and be configured to be hermetically connected to the cryoablation probe. In various embodiments, the cryoablation shaft may be disconnected from the probe insulating manifold 1310 and connected to the integrity test manifold 1312, or vice versa. In various embodiments, when the cryoablation probe is connected to the probe insulating manifold 1310, the vacuum chamber is in fluid communication with the working gas return path. Therefore, when the vacuum source 114 is energized and the valve 1306 is switched to its second position, the vacuum source is configured to vent the working gas return path, such as when performing a shaft integrity test.

[0241] In various embodiments, the test apparatus 1300 may include a moisture trap 1308. As defined herein, a moisture trap is any device configured to prevent unwanted moisture from entering the system. The moisture trap 1308 can be any suitable type of moisture trap, such as a collection tank, etc. In various embodiments, the moisture trap is positioned within the test apparatus 1300 between the integrity test manifold 1312 and the vacuum source 114. Human anatomy is filled with fluid, and running an axis integrity test on a damaged axis may cause bodily fluids to be drawn into the axis 104. Such fluid can be drawn into the control console via the vacuum source 114 and damage internal components of the cryoablation system. Therefore, placing a moisture trap upstream of vulnerable components (e.g., the vacuum source 114 and pressure sensor 1304) prevents such components from being damaged when performing an axis integrity test on a damaged axis.

[0242] Shaft integrity test method ( Figures 14 to 16 )

[0243] This document envisions many different methods, including, but not limited to, methods for manufacturing a cryoablation system, methods for manufacturing a test system for a cryoablation system, methods for testing a cryoablation system, methods for using a cryoablation system, and methods for using a cryoablation test system. Aspects of system / device operation described elsewhere herein can be performed as operations of one or more methods according to the various embodiments herein.

[0244] In various embodiments, the operations and method steps described herein may be performed as part of a computer-implemented method executed by one or more processors of one or more computing devices. In various embodiments, the operations and method steps described herein may be implemented as instructions stored on a non-transitory, computer-readable medium that, when executed by one or more processors, cause the system to perform the operations and / or steps.

[0245] Now for reference Figure 14 This document illustrates methods for performing axon integrity tests according to various embodiments thereof. In some embodiments, method 1400 may be performed after navigating the cryoablation axis 104 to a cryoablation site within the patient, but before pumping cryogas into the axis to perform the cryoablation procedure. In some embodiments, method 1400 may be performed before navigating the cryoablation axis 104 to the cryoablation site. In various embodiments, the cryoablation procedure may include multiple ablations. In some embodiments, method 1400 may be performed after performing a first ablation within the patient, but before performing a second ablation at the same or a different location. In some embodiments, method 1400 may be performed after a cryoablation procedure has been performed within the patient, but before performing the ablation. In some embodiments, method 1400 may be performed after ablation has been performed at a location within the patient and the cryoablation device has been navigated to a subsequent location, but before performing a subsequent cryoablation procedure.

[0246] In various embodiments, the method is performed using a cryoablation system 100. The cryoablation system may include a shaft 104 having a supply tube 324, a return tube 326, and an insulated shaft 328. The shaft may include an expansion chamber 106 toward a distal end of the shaft, wherein working fluid is configured to travel from the proximal end of the shaft to the distal end, expand in the expansion chamber, and travel between the supply tube 324 and the return tube 326 back to the proximal end of the shaft (also referred to herein as a working gas return path).

[0247] In various embodiments, method 1400 may include step 1402 of positioning vacuum source 114 in fluid communication with return line 326 and supply line 324. If the cryoablation probe is connected to probe insulation manifold 1310, step 1402 may include disconnecting the cryoablation probe from probe insulation manifold 1310 and connecting the cryoablation probe to integrity test manifold 1312. If valve 1306 is in its first position, step 1402 may further include switching the valve to its second position and positioning vacuum source 114 in fluid communication with return line 326 and supply line 324.

[0248] In various embodiments, method 1400 may include verifying that the working fluid source 110 is shut off, such that no working gas is pumped into shaft 104. In various embodiments, method 1400 may include verifying that the precooling fluid source 112 is shut off, such that no precooling fluid is pumped into shaft 104.

[0249] In various embodiments, method 1400 may include a step 1404 of evacuating the supply pipe 324 and the return pipe 326. In various embodiments, evacuation includes energizing a vacuum source 114 and positioning it in fluid communication with the space between the supply pipe 324 and the return pipe 326, such that the vacuum source is configured to evacuate the working gas return path. In various embodiments, evacuating the supply pipe 324 and the return pipe 326 will evacuate any residual fluid (e.g., air, working gas) from the working gas return path.

[0250] In various embodiments, the vacuum source 114 is energized and operated before being connected to the working gas return path via the integrity test manifold 1312. The vacuum source 114 can be set to operate until a steady state is reached before being placed in fluid communication with the supply pipe 324 and the return pipe 326. Once a steady state is reached, valve 1306 can be opened to fluidly connect the vacuum source 114 to the shaft 104.

[0251] In various embodiments, the working fluid return path is evacuated within a predetermined time period. In some embodiments, the predetermined time period may be greater than or equal to 5, 10, 15, 20, or 25 seconds. In some embodiments, the predetermined time period may be less than or equal to 100, 80, 65, 45, or 25 seconds. In some embodiments, the predetermined time period may fall within the range of 5 to 100 seconds, or 10 to 80 seconds, or 15 to 65 seconds, or 20 to 45 seconds, or may be approximately 25 seconds.

[0252] In various embodiments, method 1400 may include step 1406 of measuring the vacuum pressure within supply pipe 324 and return pipe 326 after a predetermined amount of time has evacuated. In some embodiments, waiting for at least a predetermined amount of time allows the vacuum pressure in the shaft to reach a stable state. In various embodiments, the vacuum pressure is measured using pressure sensor 1304.

[0253] In various embodiments, step 1408 may include comparing the measured vacuum pressure with a threshold pressure value. In some embodiments, the threshold pressure value may be greater than or equal to 0.00 Torr, 0.02 Torr, 0.03 Torr, or 0.05 Torr. In some embodiments, the threshold pressure value may be less than or equal to 0.10 Torr, 0.08 Torr, 0.07 Torr, or 0.05 Torr. In some embodiments, the threshold pressure value may fall within the range of 0.00 Torr to 0.10 Torr, or 0.02 Torr to 0.08 Torr, or 0.03 Torr to 0.07 Torr, or may be about 0.05 Torr. The exact threshold pressure value may vary based on the configuration of the cryoablation system, but for illustrative purposes, the threshold pressure value will be set to 0.05 Torr.

[0254] In various embodiments, method 1400 may include step 1410 of determining that there is no leakage in the shaft if the vacuum pressure is equal to or below a threshold pressure value. In various embodiments, a vacuum pressure stabilizing to be equal to or below a threshold pressure value in the space between supply pipe 324 and return pipe 326 indicates that the shaft is able to maintain a vacuum. If the shaft is able to maintain a sufficiently low vacuum pressure, it is highly likely that there is no leakage in the shaft.

[0255] In various embodiments, method 1400 may include step 1412 of determining that there is a leak in the shaft if the vacuum pressure is higher than a threshold pressure value. In various embodiments, a vacuum pressure higher than the threshold pressure value indicates that the shaft cannot maintain a sufficient vacuum. Inability to maintain a sufficiently low vacuum indicates that the shaft is damaged.

[0256] When a leak is determined in the axis, an indication of the presence of a leak in the specific axis can be logged in the console's memory system. In various embodiments, the console stores a log of cryoablation probes and test results associated with each probe, such as failure or pass, and the date and time of the test. Furthermore, an indication that a specific axis cannot be used in a cryoablation procedure after a leak is detected can be logged. In various embodiments, method 1400 may include automatically limiting the operation and / or pumping of precooling gas into the cryoablation axis 104 when a leak is determined in the axis.

[0257] In various embodiments, method 1400 may include the step of recording a leak indication when a leak is determined in the shaft. In some embodiments, the leak indication may include one or more visual and / or auditory alarms given to a system operator. In some embodiments, the leak indication may include instructions given to the operator to perform any of the following: not connecting a working and / or precooling gas supply source to the damaged shaft, removing the damaged shaft from a patient, discarding the damaged shaft, etc.

[0258] In various embodiments, method 1400 may include the step of storing a leak indication on the cryoablation probe. In some embodiments, the leak indication may be stored electronically in a storage device located within the device. For example, the device may include a data chip, such as an electrically erasable programmable read-only memory (EEPROM). In some embodiments, the data chip is housed within the handle 102. When the cryoablation probe with the leak indication is connected to the console, the console software can read the leak indication from the probe and issue an alarm to the system operator for a faulty shaft and / or restrict the pumping of cryogenic gas into the shaft.

[0259] In various embodiments, method 1400 may include continuously monitoring changes in vacuum pressure over time during a predetermined period while evacuating the supply and return tubes. In various embodiments, the cryoablation system is configured to collect data regarding axial pressure versus time, such as... Figures 15 to 16 As shown in the image.

[0260] Now for reference Figure 15 Exemplary graphs of shaft pressure versus time for three different shafts according to various embodiments herein are shown. Graph 1502 corresponds to the vacuum pressure of the first shaft, graph 1504 corresponds to the vacuum pressure of the second shaft, and graph 1506 corresponds to the vacuum pressure of the third shaft.

[0261] In various embodiments, method 1400 may include determining that the shaft is severely damaged when a sustained increase in vacuum pressure toward ambient pressure is measured. A severely damaged shaft cannot maintain any kind of vacuum, and the pressure within the shaft will eventually equal the pressure of its surrounding environment. A shaft may be severely damaged when its distal end is not closed (e.g., the distal operating tip 108 has detached) or when the shaft has significant leakage or breakage. Figure 15 In the example, graph 1502 corresponds to the pressure data of a severely damaged shaft. It can be seen that the shaft pressure increases rapidly towards ambient pressure, and a vacuum is not maintained.

[0262] Now for reference Figure 16 Exemplary graphs of axial pressure versus time for two different shafts according to various embodiments herein are shown. Figure 16 yes Figure 15 An enlarged version, in which graph 1502 has been removed for clarity.

[0263] In various embodiments, method 1400 may include monitoring an initial rise in vacuum pressure and, after the initial rise in vacuum pressure, monitoring whether the vacuum pressure stabilizes to a value above a threshold pressure value. Method 1400 may also include determining that there is a leak in the shaft based on a stable pressure above the pressure threshold. A leaking shaft may sometimes maintain a partial vacuum, but due to the presence of the leak, the vacuum pressure will not equal the vacuum threshold pressure.

[0264] exist Figures 15 to 16 In the example, graph 1504 corresponds to the pressure data of the leaking shaft. Figures 15 to 16 In the example, vacuum source 114 operates in a steady state before opening valve 1306 and connecting the vacuum source to shaft 104. Therefore, the vacuum pressure will be approximately zero until valve 1306 is opened, fluidly connecting vacuum source 114 to shaft 104. When vacuum source 114 empties any fluid (e.g., air, working gas) from shaft 104 and any connected piping, the pressure sensor will detect the initial pressure rise. Figures 15 to 16 In the example, the pressure value then peaks at approximately 13 seconds. The exact peak value of the pressure spike is defined by the volume of the shaft and the volume of any piping between the pressure sensor 1304 and the integrity test manifold 1312.

[0265] After reaching peak vacuum pressure in approximately 14 seconds, curve 1504 stabilizes (over time) at a value of approximately 4 Torr. When the vacuum pressure has stabilized at a value above the threshold pressure (0.05 Torr) (4 Torr), shaft damage (with one or more leaks) is determined.

[0266] In various embodiments, method 1400 may include monitoring an initial rise in vacuum pressure and, after the initial rise in vacuum pressure, monitoring whether the vacuum pressure stabilizes to a value equal to or below a threshold pressure value. The method may also include determining that there is no leakage in the shaft based on a stable pressure value equal to or below the threshold pressure value.

[0267] exist Figures 15 to 16 In the example, graph 1506 corresponds to the pressure data for a closed shaft (no leakage). After reaching peak vacuum in approximately 12 seconds, graph 1506 stabilizes (over time) at a value of approximately 0.01 Torr. When the vacuum pressure has stabilized to a value (0.01 Torr) below the threshold pressure value (0.05 Torr), it is determined that the shaft is undamaged (no leakage).

[0268] Evaluation of the initial vacuum pressure slope

[0269] If possible Figures 15 to 16Observedly, graphs 1502, 1504, and 1506 exhibit different rates of pressure change or slopes. These rates of change can be used to identify probes with open distal ends or leaks. In various embodiments, method 1400 may include monitoring the initial rise in vacuum pressure and measuring the rate of change of that initial rise. If the rate of change exceeds a first threshold rate of change, the method may include determining that there is a leak in the shaft.

[0270] For example, Figure 15 The curve 1502 in the figure rises very rapidly from 0 Torr to approximately 60 Torr in about 5 seconds, which is a rate of change of about 12 Torr / second. In some embodiments, the rate of change of the threshold may be greater than or equal to 5 Torr / second (0.7 kPa / second), 8 Torr / second (1.1 kPa / second), 11 Torr / second (1.5 kPa / second), 14 Torr / second (1.9 kPa / second), 17 Torr / second (2.3 kPa / second), or 20 Torr / second (2.7 kPa / second), or may be a quantity falling within the range of any of the aforementioned values.

[0271] Marking for imaging systems

[0272] Connector 334 ( Figure 3 ) and distal apex 108 ( Figure 8 and Figure 10 The device is configured to be displayed on the imaging system. The connector 334 may include a marking strip made of a radiopaque material, such as tungsten or platinum-iridium, or other suitable material. The material and size of the distal tip 108 can be configured to be displayed on the imaging system. Examples of materials for the distal tip 108 include stainless steel and nitinol. Marking at either end of the active area of ​​the device assists physicians in visually identifying the active area of ​​cryoablation in relation to patient anatomy and the location of the target area for cryoablation. Examples of imaging systems include ultrasound, fluoroscopy, cone-beam CT, and MRI systems.

[0273] Introducing options

[0274] In some embodiments, the catheter system is delivered using a sheath introduction system. An example of a sheath introduction system is a steerable sheath. Alternatively, the catheter system may be steerable. In another embodiment, the catheter system includes a single-track lumen along a portion of the catheter for easy insertion.

[0275] The concepts described herein can be applied and used in conjunction with the cryoablation systems and components described in the following four U.S. non-provisional patent applications, all filed May 22, 2024, the entire contents of which are incorporated herein by reference: U.S. non-provisional patent application No. 18 / 671,489 entitled “Cryoablation Catheter Shaft Construction”; U.S. non-provisional patent application No. 18 / 671,677 entitled “Multi-Gas Circuit Connector and Method for Cryoablation Systems”; U.S. non-provisional patent application No. 18 / 671,727 entitled “Delivery System for Cryoablation Devices”; and U.S. non-provisional patent application No. 18 / 671,742 entitled “Distal Tip Structure for Cryoablation Probes”.

[0276] It should be noted that, as used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural indicators unless otherwise expressly indicated in the content. It should also be noted that the term “or” is generally used in the sense of including “and / or” unless otherwise expressly indicated in the content.

[0277] It should also be noted that, as used in this specification and the appended claims, the term "configured as" describes a system, device, or other structure that is constructed or configured to perform a particular task or employ a particular configuration. The term "configured as" may be used interchangeably with other similar phrases, such as arranged and configured as, constructed and arranged as, constructed as, manufactured and arranged as, etc.

[0278] All disclosures and patent applications in this specification are intended to be at the level of a person skilled in the art to which this invention pertains. All disclosures and patent applications are incorporated herein by reference to the extent that each individual disclosure or patent application is specifically and individually indicated to be incorporated by reference.

[0279] As used herein, a description of a range of numbers represented by endpoints should include all numbers falling within that range (e.g., 2 to 8 includes 2.1, 2.8, 5.3, 7, etc.).

[0280] The headings used herein are provided for compliance with the recommendations of 37 CFR 1.77 or otherwise for providing organizational guidance. These headings should not be construed as limiting or characterizing the invention as set forth in any of the claims arising from this invention. As an example, although the headings refer to the “technical field,” such claims should not be limited by the language chosen under that heading to describe the so-called technical field. Furthermore, the description of the technology in the “Background Art” section does not constitute an endorsement of the fact that “the technology is prior art to any of the inventions herein.” The “Summary of the Invention” is also not considered a characterization of the invention set forth in the published claims.

[0281] The embodiments described herein are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the detailed embodiments below. Rather, these embodiments were chosen and described to enable those skilled in the art to understand and appreciate the principles and practices of the invention. Therefore, various aspects have been described with reference to specific and preferred embodiments and techniques. However, it should be understood that many variations and modifications can be made without departing from the spirit and scope of this document.

Claims

1. A method for detecting leakage in a shaft of a cryoablation system, the shaft including a supply pipe, a return pipe, and an expansion chamber toward a distal end of the shaft, the shaft being configured to allow working fluid to travel from a proximal end of the shaft to the distal end, expand in the expansion chamber, and travel between the supply pipe and the return pipe back to the proximal end of the shaft, the method comprising: The vacuum pump is positioned in fluid communication with the return pipe and the supply pipe; The supply pipe and the return pipe are evacuated. After a predetermined amount of time has evacuated, the vacuum pressure in the supply tube and the return tube is measured. If the vacuum pressure is equal to or lower than the threshold pressure value, it is determined that there is no leakage in the shaft; as well as If the vacuum pressure is higher than the threshold pressure value, then a leak is determined in the shaft.

2. The method of claim 1, further comprising recording a leakage indication when a leakage is determined in the shaft.

3. The method of claim 1, wherein the threshold pressure is about 0.05 Torr (6.67 Pa).

4. The method of claim 1, wherein the predetermined time is between about 10 seconds and about 45 seconds.

5. The method of claim 1, further comprising continuously monitoring the vacuum pressure over time during the predetermined time period while evacuating the supply pipe and the return pipe.

6. The method of claim 5, further comprising determining that the shaft is not closed at the distal end when the vacuum pressure is measured to be continuously increasing toward ambient pressure.

7. The method according to claim 5, further comprising: Monitor the initial rise in the vacuum pressure; Following the initial increase in vacuum pressure, it was detected that the vacuum pressure had stabilized to a value higher than the threshold pressure value; and A leak was found in the shaft.

8. The method according to claim 5, further comprising: Monitor the initial rise in the vacuum pressure; Following the initial increase in vacuum pressure, it was monitored that the vacuum pressure had stabilized to a value equal to or below the threshold pressure value; and It was confirmed that there was no leakage in the shaft.

9. The method according to claim 5, further comprising: Monitor the initial rise in the vacuum pressure; Measure the rate of change of the vacuum pressure during the initial increase; as well as If the rate of change is higher than a threshold rate, then the axis is determined to be damaged.

10. The method of claim 1, wherein the method is performed prior to the introduction of the cryoablation system into the patient.

11. The method of claim 1, wherein the method is performed after the cryoablation system has been introduced into the patient, during or after guiding the cryoablation system to the treatment site.

12. The method of claim 1, wherein the method is performed after a first cryoablation procedure is completed using the cryoablation system and before a second cryoablation procedure is performed using the cryoablation system.

13. A cryoablation system, comprising: Working gas circuit; Vacuum chamber; A vacuum pump configured to evacuate one of the working gas circuit and the vacuum chamber; A control console configured to switch the vacuum pump between the working gas circuit and the vacuum chamber; and A pressure sensor configured to measure the vacuum pressure in the working gas circuit; The console is also configured to: Switch the vacuum pump to the working gas circuit; The vacuum pump is controlled to evacuate the working gas circuit; After a predetermined amount of time has evacuated, the vacuum pressure in the working gas circuit is measured using the pressure sensor; and If the vacuum pressure is higher than the threshold pressure value, the shaft is determined to be damaged.

14. The cryoablation system of claim 13, wherein the control console is further configured to evacuate the working gas circuit and continuously monitor the vacuum pressure over time during the predetermined time period.

15. The cryoablation system of claim 14, wherein the console is further configured to measure a continuous increase in the vacuum pressure toward ambient pressure and to determine that the shaft is not closed at the distal end.

16. The cryoablation system of claim 14, wherein the control console is further configured to: Monitor the initial rise in the vacuum pressure; Following the initial increase in vacuum pressure, it was detected that the vacuum pressure had stabilized to a value higher than the threshold pressure value; and A leak was found in the shaft.

17. A cryoablation system, comprising: Precooling fluid circuit; Working fluid circuit; Vacuum circuit; as well as Shaft, the shaft comprising: An insulating portion, wherein the vacuum circuit is defined within the insulating portion; and An expansion chamber, the expansion chamber comprising: A supply pipe having a distal outlet in the expansion chamber, wherein fluid from the working fluid circuit travels through the supply pipe and expands in the expansion chamber; A first layer, wherein the first layer is configured to contain fluid from the working fluid circuit; and A second layer, wherein the second layer is configured to increase the radial strength of the expansion chamber; The shaft has a lower burst strength at a first position in the insulating portion and a higher burst strength at a second position in the expansion chamber.

18. The cryoablation system of claim 17, wherein the shaft comprises an inner metal tube, and the first layer seals to the inner metal tube at a distal end thereof, wherein the first position is a sealed position located between the first layer and the inner metal tube.

19. The cryoablation system of claim 17, wherein the first layer comprises PET and the second layer comprises a polymer or a woven material.

20. The cryoablation system of claim 17, further comprising a burst valve at the first location.

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