Introducers for electrosurgical instruments

Abstract

Various embodiments provide an introducer for introducing an electrosurgical instrument into a patient's body, the introducer including a tubular member defining a lumen through which the electrosurgical instrument can be inserted, and a cooling assembly configured to remove heat from the tubular member. Other embodiments provide an electrosurgical system including the electrosurgical instrument and the introducer.

Description

[Technical field]

[0001] The present invention relates to an introducer for introducing electrosurgical instruments into a patient's body. The introducer may be used to perform percutaneous electrosurgery and electrosurgery involving surgical inspection devices. [Background technology]

[0002] Electromagnetic (EM) energy, specifically certain microwave and radio frequency (RF) energy, has proven useful in electrosurgery for its ability to cut, coagulate, and ablate body tissue. Typically, devices for delivering EM energy to body tissue include a generator with a source of EM energy and an electrosurgical instrument connected to the generator to deliver the energy to the tissue. Conventional electrosurgical instruments are often designed to be inserted percutaneously into the patient's body. However, it can be difficult to place the instrument percutaneously within the body, for example, when the target site is within a moving, thin-walled section of the lung or gastrointestinal (GI) tract. Other electrosurgical instruments can be delivered to the target site by a surgical inspection device (e.g., an endoscope) that can pass through body channels, such as the airways or lumens of the esophagus or colon. This allows for minimally invasive treatments, which can reduce patient mortality and reduce operative and postoperative complication rates.

[0003] Tissue ablation using microwave EM energy is based on the fact that living tissue is largely composed of water. Human soft organ tissue is typically between 70% and 80% water. Water molecules have a permanent electric dipole moment, meaning that an imbalance of charge exists across the molecule. This charge imbalance causes the molecule to move in response to the force generated by the application of a time-varying electric field. The reason for this is that the molecule rotates to align its electric dipole moment with the polarity of the applied electric field. At microwave frequencies, the fast molecular vibrations lead to frictional heating and the resulting dissipation of the field energy in the form of heat. This is known as dielectric heating. Water (the main component of blood) has a much higher dipole moment than fatty tissue, so heating of water molecules in blood occurs more quickly than heating of fatty molecules for the same electric field.

[0004] This principle is utilized in microwave ablation therapy, where water molecules in targeted tissue are rapidly heated by application of a localized electromagnetic field at microwave frequencies, leading to tissue coagulation and cell death. It is known to use microwave emitting probes to treat a variety of conditions in the lungs and other organs. For example, in the lungs, microwave radiation can be used to treat asthma and to ablate tumors or lesions.

[0005] RFEM energy can be used for cutting and / or coagulation of biological tissue. Methods of cutting using RF energy work on the principle that when an electric current (aided by the ionic content of the cells) is passed through a tissue matrix, the impedance to the flow of electrons across the tissue generates heat. When a pure sine wave is applied to the tissue matrix, enough heat is generated within the tissue to evaporate the water in the tissue. This causes a large increase in the internal pressure of the cells. This cannot be controlled by the cell membrane and leads to the rupture of the cells. When this occurs over a large area, the tissue is seen to be cut transversely.

[0006] One of the challenges in delivering microwave and / or RF energy to a treatment site located within the body is how to prevent undesirable effects caused by losses from the cables that transport the microwave energy to the treatment site. These losses often manifest as heating of the cables, which in turn can heat and potentially damage the surrounding biological tissue. Summary of the Invention [Means for solving the problem]

[0007] In its most general form, the present invention provides an introducer for introducing an electrosurgical instrument into a patient's body, the introducer including a cooling assembly configured to remove heat from the introducer. During operation of the electrosurgical instrument, the electrosurgical instrument may heat up due to, for example, losses in the instrument's transmission line (or cable) used to deliver microwave and / or RF energy to the emitting tip of the instrument. When the electrosurgical instrument is introduced into the patient's body via an introducer of the present invention, the cooling assembly may be used to efficiently remove heat generated by the electrosurgical instrument. The introducer may also act as a cryo-barrier between the electrosurgical instrument and the patient, such that the introducer may act to reduce the transfer of heat from the electrosurgical instrument to the patient. In this manner, it may be possible to avoid heating of tissue along the length of the electrosurgical instrument to avoid tissue damage outside of the targeted treatment area.

[0008] According to a first aspect of the present invention, there is provided an introducer for introducing an electrosurgical instrument into a patient's body, the introducer comprising: a tubular member defining a lumen through which the electrosurgical instrument can be inserted; and a cooling assembly configured to remove heat from the tubular member.

[0009] The tubular member may be any suitable hollow member defining a lumen for receiving an electrosurgical instrument. The tubular member may, for example, have a substantially cylindrical shape. The lumen may be a channel defined within the tubular member along a length of the tubular member, the channel being dimensioned to receive an electrosurgical instrument.

[0010] The lumen is sized such that when the electrosurgical instrument is inserted through the lumen, an outer surface of the electrosurgical instrument contacts an inner surface of the tubular member. For example, the cross-sectional area of ​​the lumen may be configured to substantially match a cross-sectional area of ​​the electrosurgical instrument. This may ensure that heat generated by the electrosurgical instrument may be transferred to the tubular member when the electrosurgical instrument is inserted into the lumen. In some cases, the lumen may be sized to form an interference fit with the electrosurgical instrument when the electrosurgical instrument is inserted into the lumen.

[0011] In use, an electrosurgical instrument may be introduced into a patient's body via the introducer. The electrosurgical instrument may be inserted through a lumen within the tubular member until the emitting tip of the electrosurgical instrument protrudes beyond the distal end of the tubular member and reaches the target treatment site.

[0012] The tubular member may be configured to be percutaneously inserted into the patient's body. In such a case, an introducer may first be percutaneously inserted into the patient's body. An electrosurgical instrument may then be inserted through a lumen in the tubular member until the emitting tip of the electrosurgical instrument reaches a target treatment site within the patient.

[0013] In some cases, the tubular member may be configured to be inserted into a patient's body via an examination device, such as a laparoscope. In such cases, the tubular member may be sized to fit within a working channel of the examination device. After inserting the tubular member into the examination device, an electrosurgical instrument may then be inserted through a lumen within the tubular member until the emitting tip of the electrosurgical instrument reaches a target treatment location within the patient.

[0014] The tubular member may include a thermally conductive material. For example, the tubular member may be at least partially formed of a thermally conductive material. For example, the tubular member may be formed of a metal (e.g., aluminum, copper, brass, gold, diamond) or other thermally conductive material. In some cases, the tubular member may be formed of a hollow cylindrical tube formed of a thermally conductive material.

[0015] In some embodiments, the tubular member may include a thermally conductive dielectric (e.g., non-metallic) material. This may minimize interference of the tubular member with microwave energy radiated by the radiating tip of the electrosurgical instrument and may prevent back-propagation of microwave energy along the length of the tubular member. For example, the tubular member may be formed of a thermally conductive dielectric material. As one example, alumina (or aluminum oxide) may be a suitable thermally conductive dielectric material.

[0016] As used herein, a thermally conductive material has a thermal conductivity of at least 10 W.m -1 .K -1 Therefore, the tubular member may be made of a material having a thermal conductivity of at least 10 W.m -1 .K -1 In some embodiments, the thermally conductive material may include a material having a thermal conductivity of at least 20 W.m -1 .K -1 , 40W.m -1 .K -1 , 60W.m -1 .K -1, 80W.m -1 .K -1 , 100W.m -1 .K -1 , 120W.m -1 .K -1 , 140W.m -1 .K -1 , 160W.m -1 .K -1 , 180W.m -1 .K -1 , or 200W.m -1 .K -1 A higher thermal conductivity may allow for more efficient removal of heat from the electrosurgical instrument inside the lumen of the tubular member. An example of a suitable thermally conductive material is copper (thermal conductivity ≈ 398 W.m -1 .K -1 ), aluminum (thermal conductivity ≒ 237 W.m -1 .K -1 ), brass (thermal conductivity ≒ 109 W.m -1 .K -1 ), gold (thermal conductivity ≒ 315 W.m -1 .K -1 ), diamond (thermal conductivity ≒ 1000~2200W.m -1 .K -1 ), alumina (thermal conductivity ≒ 30W.m -1 .K -1 ). Other thermally conductive materials may also be used.

[0017] The rate of thermal conductivity through the tubular member may depend on the wall thickness of the tubular member, and therefore the wall thickness of the tubular member may be adjusted to achieve a desired rate of thermal conductivity through the tubular member.

[0018] The cooling assembly may include any suitable active and / or passive components configured to remove heat from the tubular member. This may serve to ensure that the temperature of the tubular member does not rise excessively, which may result in damage to the surrounding tissue. This may also serve to remove heat from the electrosurgical instrument to maintain the electrosurgical instrument at an acceptable temperature during use. Removal of heat from the electrosurgical instrument may improve the performance of the electrosurgical instrument and avoid damage to the electrosurgical instrument caused by excessive heating. This may also allow the electrosurgical instrument to deliver higher power levels through the emitting tip. This may allow, for example, to treat a larger target area.

[0019] The cooling assembly may include a heat sink thermally coupled to the tubular member. As such, the heat sink may serve to extract heat from the tubular member to reduce the temperature of the tubular member. The heat sink may be formed of a thermally conductive material, for example a metal such as copper, aluminum, or brass. The heat sink may be in the form of a block of thermally conductive material thermally coupled to the tubular member. In some cases, the heat sink may include one or more fins. The one or more fins may serve to increase the surface area of ​​the heat sink, which may facilitate cooling of the heat sink, for example, when the heat sink is cooled by a fan and / or a coolant.

[0020] The heat sink may be thermally coupled to the tubular member via any suitable link that allows for the transfer of heat from the tubular member to the heat sink. For example, the heat sink may be thermally coupled to the tubular member via a wire or cable formed of a thermally conductive material (e.g., metal). In some cases, the heat sink may be directly connected to, e.g., in contact with, the tubular member.

[0021] The heat sink may have a higher thermal capacity than the tubular member, which may cause heat to flow from the tubular member to the heat sink, thereby allowing heat to be efficiently removed from the tubular member.

[0022] The heat sink may be provided at or near the proximal end of the tubular member. In use, the proximal end of the tubular member may be located outside the patient, while the distal end of the tubular member may be located inside the patient's body. Thus, locating the heat sink at or near the proximal end of the tubular member may ensure that heat is removed from the tubular element to a location outside the patient's body and facilitate cooling of the heat sink.

[0023] The heat sink may be provided in a handle of the tubular member. This may facilitate integration of the heat sink into the introducer and improve handling and maneuverability of the tubular member. The handle may be provided at a proximal end of the tubular member such that, in use, a user may grip the tubular member by the handle to facilitate positioning and insertion of the tubular member into a patient. The handle may be formed by the heat sink. Alternatively, the heat sink may be contained within the handle.

[0024] The heat sink may be thermally coupled to the tubular member via a heat pipe. This may provide a strong thermal link between the tubular member and the heat sink to allow efficient removal of heat from the tubular member. The heat pipe may be a conventional heat pipe configured to transfer heat from the tubular member to the heat sink. A first end of the heat pipe may be connected to the tubular member, while a second end of the heat pipe may be connected to the heat sink. In some cases, the second end of the heat pipe may comprise the heat sink.

[0025] The cooling assembly may be configured to actively cool the heat sink. Actively cooling the heat sink may allow for more efficient removal of heat from the heat sink, which in turn may allow for more heat to be removed from the tubular member (and any electrosurgical instrument contained within the tubular member). Active cooling may refer to a type of cooling that requires electrical power. Active cooling may involve contacting a fluid flow with the heat sink to remove heat from the heat sink.

[0026] The cooling assembly may include a fan configured to actively cool the heat sink. The fan may be arranged to generate an airflow directed at the heat sink such that the heat sink is cooled by the airflow. This may allow for efficient removal of heat from the heat sink.

[0027] The cooling assembly may be configured to actively cool the heat sink with a coolant fluid. The cooling assembly may be configured to have a flow of coolant fluid remove heat from the heat sink. Thus, the heat sink may act as a heat exchanger between the tubular member and the coolant fluid. In some cases, the coolant fluid may come into direct contact with the heat sink, e.g., flow over and / or through it. In other cases, the coolant fluid may not come into direct contact with the heat sink, but may flow through tubes or conduits that are in thermal contact with the heat sink.

[0028] The coolant fluid may be a liquid or a gas. For example, suitable coolant fluids may include water, liquid or gaseous nitrogen, and liquid or gaseous helium.

[0029] The cooling assembly may include a coolant fluid source arranged to provide a flow of coolant fluid. The coolant source may be connected to the heat sink via one or more conduits such that the coolant fluid may flow from the coolant fluid source to the heat sink. As one example, the coolant fluid source may be in the form of a pressurized container containing the coolant fluid. As another example, the coolant fluid source may be in the form of a coolant fluid container having a pump or other suitable mechanism for flowing the coolant fluid to the heat sink.

[0030] The heat sink may include one or more channels formed therein through which a coolant fluid may flow, which may facilitate heat exchange between the coolant fluid and the heat sink.

[0031] The cooling assembly may include a heat exchanger configured to actively cool a heat sink. The heat sink may be thermally coupled to the heat exchanger such that heat is removed from the heat sink by the heat exchanger. For example, the heat exchanger may include a hot end and a cold end, with the heat sink thermally coupled to the cold end of the heat exchanger.

[0032] Alternatively, the heat sink may be passively cooled. For example, the heat sink may be placed in air such that the heat sink is cooled by the air. In some cases, the heat sink may be contacted with a coolant. For example, the heat sink may be placed in a vessel that contains a coolant. Suitable coolants may include, for example, water, liquid nitrogen, or liquid helium.

[0033] The cooling assembly may include a heat pump configured to remove heat from the tubular member. For example, the heat pump may be a thermoelectric heat pump, such as a Peltier cooler. The heat pump may be mounted directly on a surface of the tubular member, for example near a proximal end of the tubular member. In cases where the cooling assembly includes a heat sink, the heat pump may be configured to remove heat from the heat sink, for example, the heat pump may be mounted on a surface of the heat sink.

[0034] The tubular member may include one or more channels defined on or in a sidewall of the tubular member, and the cooling assembly may be configured to circulate a coolant fluid through the one or more channels to remove heat from the tubular member. By circulating the coolant fluid through the one or more channels, heat may be removed from the tubular member. The one or more channels may extend along a length of the tubular member. This may allow for heat removal along the length of the tubular member, which may lead to a substantially uniform temperature along the length of the tubular member. For example, the one or more channels may extend from a proximal end of the tubular member to a location at or near a distal end of the tubular member.

[0035] The cooling assembly may include a coolant fluid source configured to circulate a coolant fluid through one or more channels. The coolant fluid may be a liquid or a gas. For example, suitable coolant fluids may include water, liquid or gaseous nitrogen, and liquid or gaseous helium.

[0036] The one or more channels may include a first channel ("into channel") through which coolant fluid may be introduced into the tubular member, and a second channel ("outto channel") through which coolant fluid may exit the tubular member. The first and second channels may be connected together via a connecting channel, e.g., located near the distal end of the tubular member. The inlet of the first channel may be connected at its proximal end to a coolant fluid source to receive the coolant fluid from the coolant fluid source. The outlet of the second channel may be suitably connected to collect or recirculate exhaust coolant fluid exiting the second channel.

[0037] The tubular member may include one or more contact elements disposed within the lumen and arranged to bear against an exterior surface of the electrosurgical instrument when the electrosurgical instrument is inserted through the lumen. The one or more contact elements may serve to provide a thermal link between the tubular member and the electrosurgical instrument when the electrosurgical instrument is received within the lumen. The one or more contact elements may be formed of a thermally conductive material, such as a metal.

[0038] The one or more contact elements may include a resilient material, which may serve to ensure that contact is maintained with the electrosurgical instrument while facilitating insertion of the electrosurgical instrument through the lumen. For example, each of the one or more contact elements may include a spring or spring-like element configured to urge the contact element against an outer surface of the electrosurgical element when the electrosurgical instrument is inserted through the lumen.

[0039] The tubular member may include a distal end formed of a dielectric material. This may minimize interference of the distal end of the tubular member with microwave energy radiated by the radiating tip of the electrosurgical instrument and may reduce back propagation of microwave energy along the length of the tubular member. For example, the distal end of the tubular member may be formed of a ceramic material (e.g., zirconia) or a polymeric material (e.g., polyetheretherketone, or PEEK).

[0040] The tubular member may include a pointed distal end. The pointed distal end may enable the tubular member to pierce the skin to facilitate percutaneous insertion of the tubular member into the patient. In this manner, the tubular member may be used to pierce the skin of a patient and to percutaneously introduce an electrosurgical instrument into the patient. When the tubular member includes a distal end formed of a dielectric material, the pointed distal end may be formed of the dielectric material.

[0041] The pointed distal end may be integrally formed with the remainder of the tubular member, for example if the distal end is formed of the same material as the remainder of the tubular member, or alternatively if the distal end is formed of a different material than the remainder of the tubular member, the distal end may be secured to the distal end of the tubular member via any suitable means (e.g., via an adhesive or a mechanical fastening mechanism).

[0042] The tubular member may include an outer layer formed of a biocompatible material. For example, the tubular member may include an inner layer formed of a thermally conductive material coated or covered with a biocompatible material. The thermally conductive material may be a metal (e.g., aluminum, copper, brass). The biocompatible material may be a metal (e.g., gold or silver) or the biocompatible material may be a polymeric material (e.g., polytetrafluoroethylene-PTFE). The biocompatible material may serve to protect the tubular member. In some cases, the biocompatible material may be a non-stick material (e.g., PTFE) to facilitate insertion of the tubular member into a patient.

[0043] The tubular member may include an inner layer formed of a thermally conductive material and an outer layer formed of an insulating material. In this manner, the thermally conductive inner layer may absorb and transfer heat from the electrosurgical instrument when the electrosurgical instrument is received within the lumen. The insulating outer layer may act as a thermal barrier against heat generated by the electrosurgical instrument to minimize heating of surrounding tissue. The inner and outer layers may be formed of different materials secured together.

[0044] The thermal conductivity of the thermally conductive material may be greater than the thermal conductivity of the insulating material. Any of the thermally conductive materials described above may be used as the thermally conductive material for the inner layer (e.g., copper, brass, aluminum, etc.). Examples of suitable insulating materials include polystyrene (thermal conductivity ≈ 0.0081-0.026 Wm -1 .K -1 ), polyurethane (thermal conductivity ≒ 0.032~0.05Wm -1 .K -1 ), glass (thermal conductivity ≒ 0.18~0.96Wm -1 .K -1 ), mica (thermal conductivity ≒ 0.71 Wm -1 .K -1 ), PTFE (thermal conductivity ≒ 0.25 Wm -1 .K -1), but other insulating materials may also be used. Generally, insulating materials are required to have a thermal insulation capacity of 10 W.m -1 .K -1 Preferably, the insulating material has a thermal conductivity of less than 1 W.m -1 .K -1 The thermal conductivity of the material may be less than 1000 .mu.m.

[0045] The inner and outer layers may be formed as concentric tubes, which may be secured together, for example, via a suitable adhesive or epoxy.

[0046] In some cases, the inner layer may be formed as a coating on the inner surface of the outer layer. For example, the outer layer may be formed by a hollow tube of thermally insulating material (e.g., mica). The inner layer may thus be formed by coating the inner surface of the hollow tube with a thermally conductive material (e.g., gold).

[0047] The thickness of the outer layer may be greater than the thickness of the inner layer, which may reduce heat leakage from the electrosurgical instrument to the surrounding tissue. For example, the thickness of the inner layer may be between 15% and 25% of the thickness of the outer layer.

[0048] If the tubular member includes an outer layer formed of a biocompatible material, the biocompatible outer layer may be formed of a thermally insulating material, for example, the outer layer may be formed of PTFE.

[0049] When the tubular member includes the inner and outer layers described above, the cooling assembly may be configured to remove heat from one or both of the inner and outer layers of the tubular member. In some cases, the cooling assembly may be directly coupled to the inner layer to more efficiently remove heat from the inner layer. For example, the outer layer may include one or more holes through which the cooling assembly is thermally coupled to the inner layer.

[0050] When the tubular member includes the inner layer and the outer layer as described above, and the tubular member includes the one or more channels as described above, the one or more channels may be defined in the inner layer and / or the outer layer of the tubular member. In one embodiment, the one or more channels may include a first channel ("inward channel"), through which the coolant fluid is introduced into the tubular member and the first channel is formed in the inner layer of the tubular member. The one or more channels may also include a second channel ("outward channel"), through which the coolant fluid may exit the tubular member and the second channel is formed in the outer layer of the tubular member. In this manner, the coolant fluid first passes through the inner layer and then through the outer layer, so that heat can be more efficiently removed from the inner layer.

[0051] In some embodiments, the proximal portion of the tubular member may be flexible and the distal portion of the tubular member may be rigid. The rigidity of the distal portion of the tubular member may be greater than the rigidity of the proximal portion of the tubular member. In use, the rigid distal portion of the tubular member may be inserted into a patient while the flexible proximal portion of the tubular member may be located outside of the patient. The rigid distal portion of the tubular member may facilitate insertion of the distal portion into the patient. The flexible proximal portion may facilitate handling of the introducer. In particular, the flexible portion of the tubular member may be beneficial when the electrosurgical instrument includes a long cable or transmission line because the flexible portion of the tubular member may allow the cable of the electrosurgical instrument to flex or bend. This may facilitate connection of the electrosurgical instrument to the electrosurgical generator. The length of the proximal portion may be greater than the length of the distal portion, for example, to facilitate receipt of the cable of the electrosurgical instrument within the proximal portion.

[0052] The distal portion of the tubular member may comprise a rigid thermally conductive material, for example, a rigid metal tube.

[0053] The proximal portion of the tubular member may comprise a flexible, thermally conductive material. As used herein, flexible material may refer to a material that is bendable or pliable. For example, the proximal portion of the tubular member may be formed of a braided material, such as a metallic braid, to provide flexibility to the proximal portion.

[0054] The length of the tubular member may be 30 cm or more. Such a length may facilitate percutaneous insertion of the tubular portion into the patient's body and ensure that the patient's body is adequately protected from heat generated by the electrosurgical instrument.

[0055] The introducer of the first aspect of the invention may form part of an electrosurgical system. Thus, according to a second aspect of the invention, there is provided an electrosurgical system comprising an electrosurgical instrument having a transmission line for delivering microwave and / or radio frequency electromagnetic (EM) energy and a radiating tip attached to a distal end of the transmission line configured to receive and deliver microwave and / or radio frequency EM energy to living tissue, and an introducer according to the first aspect of the invention, wherein the electrosurgical instrument is insertable through the lumen of the tubular member. Any of the features of the introducer described above with respect to the first aspect of the invention may be shared with the second aspect of the invention.

[0056] The electrosurgical instrument may be configured to deliver microwave and / or radio frequency EM energy to the living tissue. The microwave and / or radio frequency EM energy may be transferred along a transmission line to a radiating tip. The radiating tip is configured to deliver the EM energy to the living tissue. The radiating tip may include one or more electrodes positioned to deliver the EM energy to the living tissue.

[0057] The transmission line may be any suitable cable for transporting microwave and / or radio frequency EM energy. For example, the transmission line may be a flexible coaxial cable. A distal end of the transmission line may be electrically connected to the radiating tip to transport the EM energy from the transmission line to the radiating tip.

[0058] The electrosurgical instrument may be sized such that it is insertable through the lumen of the tubular member. For example, the outer diameter of the electrosurgical instrument may be equal to or less than the diameter of the lumen of the tubular member. In use, a portion of the transmission line may be received within the lumen of the tubular member, while the emitting tip may protrude from the distal end of the tubular member. In this manner, the emitting tip may deliver EM energy to the targeted tissue, while the tubular member may act to protect the patient's body from heat generated within the transmission line.

[0059] The system may further include an electrosurgical generator configured to generate microwave and / or radio frequency EM energy, and the electrosurgical generator may be electrically connected to a proximal end of the transmission line to deliver EM energy to the transmission line.

[0060] According to a third aspect of the present invention, there is provided a method of introducing an electrosurgical instrument into a patient's body comprising inserting a tubular member of an introducer into the patient's body, inserting the electrosurgical instrument through a lumen of the tubular member such that an emitting tip of the electrosurgical instrument protrudes beyond a distal end of the tubular member, and removing heat from the tubular member using a cooling assembly of the introducer.

[0061] The introducer may be an introducer according to the first aspect of the invention. The introducer and the electrosurgical instrument may be part of an electrosurgical system according to the second aspect of the invention.

[0062] The tubular member may be inserted percutaneously into the patient's body. Alternatively, the tubular member may be inserted into the patient's body via a surgical exploration device, for example via a laparoscope.

[0063] An electrosurgical instrument may be inserted through the lumen of the tubular member until the emitting tip of the electrosurgical instrument protrudes beyond the distal end of the tubular member. In this manner, the emitting tip may be exposed such that it may come into contact with the targeted tissue.

[0064] Thus, heat may be removed from the tubular member using a cooling assembly of the introducer. This may include passively and / or actively removing heat from the tubular member, depending on the configuration of the cooling assembly used. If the cooling assembly includes an active component (e.g., a fan), removing heat from the tubular member may include activating the active component of the cooling assembly.

[0065] As used herein, the term "inner" may refer to a location radially closer to the center (e.g., axis) of the tubular member and / or electrosurgical instrument, and the term "outer" may refer to a location radially farther from the center (axis) of the tubular member and / or electrosurgical instrument.

[0066] The term "conductive" is used herein, unless the context indicates otherwise, to mean electrically conductive.

[0067] As used herein, the terms "proximal" and "distal" refer to the ends of the tubular member or electrosurgical instrument. In use, the proximal end is closer to a generator for providing RF and / or microwave energy, while the distal end is further from the generator. In particular, the proximal ends of the tubular member and electrosurgical instrument may be located outside the patient's body, while the distal ends of the tubular member and electrosurgical instrument may be located inside the patient's body, e.g., proximal to the target tissue.

[0068] "Microwave" may be used generally herein to refer to the frequency range of 400 MHz to 100 GHz, with the range of 1 GHz to 60 GHz being preferred. Preferred spot frequencies for microwave EM energy include 915 MHz, 2.45 GHz, 3.3 GHz, 5.8 GHz, 10 GHz, 14.5 GHz, and 24 GHz. 5.8 GHz may be preferred. The device may deliver energy at two or more of these microwave frequencies.

[0069] The term "radio frequency" or "RF" is sometimes used to indicate frequencies between 300 kHz and 400 MHz.

[0070] Embodiments of the present invention are discussed below with reference to the accompanying drawings. [Brief description of the drawings]

[0071] [Figure 1] FIG. 1 is a schematic diagram of an introducer according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic diagram of an introducer according to an embodiment of the invention. [Diagram 3] FIG. 3 is a schematic diagram of an introducer according to an embodiment of the invention. [Figure 4] FIG. 4 is a cross-sectional view of a tubular member that may form part of an introducer according to an embodiment of the invention. [Diagram 5]FIG. 5 is a cross-sectional view of a tubular member that may form part of an introducer according to an embodiment of the invention. [Figure 6] FIG. 6 is a schematic diagram of an introducer according to an embodiment of the invention. [Figure 7] FIG. 7 is a schematic diagram of an introducer according to an embodiment of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0072] 1 is a schematic diagram of an introducer 100 according to an embodiment of the present invention. The introducer 100 includes a tubular member 102 defining a lumen 104 through which an electrosurgical instrument 106 can be inserted.

[0073] The tubular member 102 is formed by a hollow tubular tube of a thermally conductive material. For example, the tubular member may be formed of copper, aluminum, or brass. The tubular member may be coated with a non-stick biocompatible material, such as PTFE, to facilitate percutaneous insertion of the tubular member into a patient's body.

[0074] A lumen 104 within the tubular member 102 is sized to receive an electrosurgical instrument 106. Specifically, the lumen 104 is sized such that an outer surface of the electrosurgical instrument 106 contacts the walls of the lumen 104 when the electrosurgical instrument 106 is inserted through the lumen 104. For example, the cross-sectional area of ​​the lumen 104 may substantially match the cross-sectional area of ​​the electrosurgical instrument 106. In this manner, the electrosurgical instrument 106 may be thermally coupled to the tubular member 102 such that heat may flow from the electrosurgical instrument 106 to the tubular member 102. The lumen 104 and the electrosurgical instrument 106 may have a substantially circular cross-sectional area.

[0075] The tubular member 102 includes a pointed distal end 108 formed of a dielectric material, such as, for example, PEEK. The pointed distal end 108 may be secured to the remainder of the tubular member 102 via a suitable adhesive. The pointed distal end 108 may facilitate piercing a patient's skin to allow the tubular member to be percutaneously inserted into the patient.

[0076] The tubular member 102 further includes a heat sink 110 attached to a proximal end of the tubular member 102. The heat sink 110 is thermally coupled to the tubular member 102 such that heat may flow from the tubular member 102 to the heat sink 110. The heat sink 110 is in the form of a block of thermally conductive material (e.g., copper, aluminum, brass). The heat sink 110 is configured such that it has a higher thermal capacity than the tubular member 102 such that heat may preferentially flow from the tubular member 102 to the heat sink 110. In this manner, the heat sink 110 may efficiently remove heat from the tubular member 102.

[0077] Because the heat sink 110 is attached to the proximal end of the tubular member 102, the heat sink 110 may also serve as a handle for the tubular member 102. As such, a user may grip the tubular member via the heat sink 110, which may facilitate manipulation of the tubular member 102. The heat sink 110 may be ergonomically shaped to facilitate gripping the heat sink 110. Additionally, the heat sink 110 may be covered with a gripping (e.g., non-slip) material, such as rubber, to facilitate gripping the heat sink 110.

[0078] The heat sink 110 includes passages (not shown) defined therein through which a coolant fluid may flow to remove heat from the heat sink 110. The passages defined in the heat sink 110 extend between an inlet 112 and an outlet 114 of the heat sink 110. The passages in the heat sink 110 may define a spiral passage to maximize the removal of heat from the heat sink 110 by the coolant fluid passing through the passages.

[0079] The introducer 100 further includes a coolant fluid source 116 configured to flow coolant fluid through passages in the heat sink 110. The coolant fluid source 116 is coupled to the inlet 112 of the heat sink 110 via a first conduit 118 (or tube) such that the coolant fluid may flow from the coolant fluid source 116 to the inlet 112 of the heat sink 110. A second conduit 120 is connected to the outlet 114 of the heat sink 110 such that the coolant fluid may flow out of the heat sink 110 via the second conduit 120 as illustrated by arrow 122. The coolant fluid exiting via the second conduit 120 may be captured, for example, in a reservoir for draining coolant fluid. As another example, the coolant fluid exiting via the second conduit 120 may be recirculated back to the coolant fluid source 116 so that the coolant fluid may be reused.

[0080] The coolant fluid source 116 includes a reservoir (or tank) that contains the coolant fluid. The coolant fluid may include a gas or a liquid. Suitable coolant fluids may include, for example, water, liquid or gaseous nitrogen, and liquid or gaseous helium. The coolant fluid source 116 is configured to flow the coolant fluid contained in the reservoir through a passageway in the heat sink 110. For example, the coolant fluid in the reservoir may be pressurized, and the coolant fluid source 116 may include a valve for controlling the flow of the coolant fluid out of the reservoir and into the first conduit 118. As another example, the coolant fluid source 116 may include a pump or other mechanism for flowing the coolant fluid from the reservoir into the first conduit 118. The heat sink 110, the coolant fluid source 116, and the conduits 118, 120 may together form a cooling assembly of the introducer 100.

[0081] In use, the tubular member 102 may be first inserted into a patient's body. The pointed distal end 108 may be used to pierce the patient's skin. The tubular member 102 may be inserted to a desired depth such that the pointed distal end 108 of the tubular member 102 is proximal to the target biological tissue within the patient. The electrosurgical instrument 106 may then be inserted through the lumen 104 within the tubular member 102.

[0082] The electrosurgical instrument 106 is configured to deliver RF and / or microwave energy to biological tissue. The electrosurgical instrument includes a transmission line 124 and an emitting tip 126 disposed at a distal end of the transmission line 124. The transmission line 124 is configured to transport RF and / or microwave energy from an electrosurgical generator connected at a proximal end of the transmission line 124. For example, the transmission line 124 may be a suitable coaxial cable. The emitting tip 126 is electrically connected to the transmission line 124 for receiving the RF and / or microwave energy and delivering the RF and / or microwave energy to the target tissue. The emitting tip may include one or more electrodes (not shown) for delivering the RF and / or microwave energy to the biological tissue. The one or more electrodes may be configured depending on the type of energy being delivered and the type of electrosurgical procedure being performed.

[0083] The electrosurgical instrument 106 may be inserted through the lumen 104 of the tubular member 102 until the emitting tip 126 protrudes beyond the pointed distal end 108 of the tubular member 102, as shown in FIGURE 1. In this manner, the emitting tip 126 may be exposed such that the emitting tip 126 may deliver RF and / or microwave power to the target tissue. In this configuration, a portion of the transmission line 124 is received within the lumen 104 of the tubular member 102. The portion of the transmission line 124 within the lumen 104 is in direct contact with the tubular member 102, such that they are in thermal contact with each other.

[0084] The cooling assembly of the introducer 100 may be activated, for example, by activating the coolant fluid source 116 such that coolant fluid is flowed through passages in the heat sink 110. This serves to remove heat from the heat sink 110.

[0085] As RF and / or microwave energy is transferred along the transmission line 124 and delivered to the target tissue via the emitting tip 126, the electrosurgical instrument 106 may heat up, for example, due to losses in the transmission line 124. As a result, heat may flow from the electrosurgical instrument 106 to the tubular member 102, which may cause the tubular member 102 to heat up. The heat may then flow from the tubular member 102 to the heat sink 110. To remove heat from the heat sink 110, the coolant fluid source 116 may be activated to flow coolant fluid through passages in the heat sink 110. As the coolant fluid flows through the passages in the heat sink 110, it may absorb heat from the heat sink 110. In this manner, the heat sink 110 may be efficiently cooled, thereby allowing the heat sink to continue to absorb heat from the tubular member 102. As a result, the tubular member 102 may be maintained at a relatively low temperature, which may avoid damage to surrounding tissue. Additionally, heat generated by the electrosurgical instrument 106 may be efficiently removed via the tubular member 102 and the heat sink 110, which may serve to maintain the electrosurgical instrument 106 at a suitable operating temperature. The flow rate of coolant fluid through passages in the heat sink 110 may be controlled (e.g., by controlling the coolant fluid source 116) to control the cooling of the heat sink 110, such that the heat sink 110 (and thus the tubular member 102) may be maintained at a desired temperature.

[0086] The electrosurgical instrument 106 and introducer 100 together may form part of an electrosurgical system, which is one embodiment of the present invention. Such an electrosurgical system may further include an electrosurgical generator connected (or connectable) at the proximal end of the transmission line 124 and configured to deliver RF and / or microwave energy to the transmission line 124.

[0087] 2 is a schematic diagram of an introducer 200 according to another embodiment of the present invention. Introducer 200 includes a tubular member 202 defining a lumen 204 through which an electrosurgical instrument 206 can be inserted. Electrosurgical instrument 206 includes a transmission line 224 and an emitting tip 226, and is similar in construction to electrosurgical instrument 106 discussed above.

[0088] Similar to the tubular member 102 discussed above, the tubular member 202 is formed of a hollow tubular tube of thermally conductive material, which may be coated with a non-stick biocompatible material. A pointed distal tip 208 formed of a dielectric material (e.g., PEEK) is provided at the distal end of the tubular member 202.

[0089] The lumen 204 is dimensioned to receive the electrosurgical instrument 206. For example, the cross-sectional area of ​​the lumen 204 may be slightly larger than the cross-sectional area of ​​the electrosurgical instrument 206. A plurality of contact elements 210 are provided on the wall of the lumen 204 and are positioned to press against an outer surface of the electrosurgical instrument 206 when the electrosurgical instrument 206 is inserted through the lumen 204. The contact elements 210 are formed of a thermally conductive material and serve to provide a thermal link between the electrosurgical instrument 206 and the tubular member 202. The contact elements 210 may be formed of a resilient (e.g., flexible) material. This may facilitate inserting the electrosurgical instrument 206 into the lumen 204 while ensuring that thermal contact is maintained between the electrosurgical instrument 206 and the tubular member 202. Each of the embodiments illustrated in Figures 1, 3, 4a, 4b, and 5 may be modified to include a contact element similar to contact element 210 within the lumen of the tubular member.

[0090] The introducer 200 further includes a heat sink 212. The heat sink 212 is thermally coupled to the tubular member 202 via a thermal link in the form of a heat pipe 214. The heat sink 212 is in the form of a block of thermally conductive material (e.g., copper, aluminum, brass) and has a thermal capacity that is greater than the thermal capacity of the tubular member 202. The heat sink 212 includes a series of fins (not shown) disposed on a surface thereof to increase the surface area of ​​the heat sink 212. The heat pipe 214 may be any suitable conventional heat pipe and serves to transfer heat from the tubular member 202 to the heat sink 212. The heat pipe 214 is connected to the tubular member 202 near the proximal end of the tubular member 202.

[0091] The introducer 200 further includes a fan 216 configured to actively cool the heat sink 212. Specifically, the fan 216 is configured to blow air onto the heat sink 212, as illustrated by arrow 218, to cool the heat sink 212. The fan 216 may be any suitable conventional fan, for example, an electric fan. The fan 216 may be powered by an external power source (not shown). The heat pipe 214, the heat sink 212, and the fan 216 may together form a cooling assembly of the introducer 200.

[0092] In the configuration shown in FIG. 2, the electrosurgical instrument 206 is inserted into the lumen 204 of the tubular member 202 such that a portion of the transmission line 224 is disposed within the lumen 204 and the emitting tip 226 protrudes beyond the pointed distal end 208 of the tubular member 202. During use of the electrosurgical instrument 206, heat generated by the electrosurgical instrument 206 may be transferred to the tubular member 202 via the contact elements 210. The heat may then flow from the tubular member 202 to the heat sink 212 via the heat pipes 214. The fan 216 may be activated to blow air across the heat sink 212 to remove heat from the heat sink 212, thereby allowing the heat sink to efficiently absorb heat from the tubular member 202. In this manner, the tubular member 202 may be maintained at a relatively low temperature, which may avoid damage to the surrounding tissue. Furthermore, heat generated by the electrosurgical instrument 206 may be efficiently removed through the tubular member 202 and the heat sink 212, which may serve to maintain the electrosurgical instrument 206 at a suitable operating temperature.

[0093] In an alternative embodiment (not shown), instead of actively cooling the heat sink with the fan 216, the heat sink 212 may be passively cooled using a coolant fluid. For example, the heat sink 212 may be submerged in a vessel containing a coolant fluid (e.g., water, liquid nitrogen, or liquid helium). In this manner, the coolant fluid may cool the heat sink 212 such that it may efficiently absorb heat from the tubular member 202.

[0094] Together, the electrosurgical instrument 206 and the introducer 200 may form part of an electrosurgical system, which is one embodiment of the present invention. Such an electrosurgical system may further include an electrosurgical generator connected (or connectable) at the proximal end of the transmission line 224 and configured to deliver RF and / or microwave energy to the transmission line 224.

[0095] 3 is a schematic diagram of an introducer 300 according to another embodiment of the present invention. Introducer 300 includes a tubular member 302 defining a lumen 304 through which an electrosurgical instrument 306 can be inserted. Electrosurgical instrument 306 includes a transmission line 324 and an emitting tip 326, and is similar in construction to electrosurgical instrument 106 discussed above.

[0096] Similar to tubular members 202 and 102 discussed above, tubular member 302 is formed from a hollow tubular tube of thermally conductive material, which may be coated with a non-stick biocompatible material. A pointed distal tip 308, formed from a dielectric material (e.g., PEEK), is provided at the distal end of tubular member 302.

[0097] A lumen 304 within tubular member 302 is dimensioned to receive an electrosurgical instrument 306. Specifically, lumen 304 is dimensioned such that an outer surface of electrosurgical instrument 306 contacts a wall of lumen 304 when electrosurgical instrument 306 is inserted through lumen 304. For example, the cross-sectional area of ​​lumen 304 may substantially match the cross-sectional area of ​​electrosurgical instrument 306.

[0098] The tubular member 304 includes a first channel 310 and a second channel 312 defined in a sidewall of the tubular member 302. The first channel 310 and the second channel 312 extend from a proximal end of the tubular member 302 toward a distal end of the tubular member 302. The proximal end of the first channel 310 is connected to a coolant fluid source 314 via a first conduit 316 such that coolant fluid can flow from the coolant fluid source 314 into the first channel 310.

[0099] The first channel 310 and the second channel 312 are connected together near the distal end of the tubular member 302 via a connecting channel 318 (shown by a dashed line in FIG. 3 ). The connecting channel 318 is defined in a sidewall of the tubular member 302 and extends between the first channel 310 and the second channel 312. In this manner, coolant fluid may flow from the first channel 310 into the second channel 312 via the connecting channel 318. The second conduit 320 is connected to a proximal end of the second channel 312 such that coolant fluid may flow from the second channel into the second conduit 320. In this manner, the first conduit 316, the first channel 310, the connecting channel 318, the second channel 312, and the second conduit 320 form a flow path along which coolant fluid may flow.

[0100] The coolant fluid source 314 is configured to circulate the coolant fluid along the flow path such that the coolant fluid flows through the first channel 310 and the second channel 312 in the tubular member 302. The coolant fluid source 314 may have a configuration similar to the coolant fluid source 116 described above. For example, the coolant fluid source 314 may include a reservoir containing the coolant fluid, and the coolant fluid source 314 may be configured to flow the coolant fluid from the reservoir to the first conduit 316. This may be accomplished by pressurizing the reservoir and controlling the flow of the coolant fluid out of the reservoir through a valve, or by providing a pump or other mechanism for causing the coolant fluid to flow out of the reservoir. The coolant fluid may include a gas or a liquid. Suitable coolant fluids may include, for example, water, liquid or gaseous nitrogen, and liquid or gaseous helium.

[0101] In the configuration shown in FIG. 3 , the electrosurgical instrument 306 is inserted into the lumen 304 of the tubular member 302 such that a portion of the transmission line 324 is disposed within the lumen 304 and the emitting tip 326 protrudes beyond the pointed distal end 308 of the tubular member 302. During use of the electrosurgical instrument 306, heat generated by the electrosurgical instrument 306 may be transferred to the tubular member 302. The coolant fluid source 314 may be actuated to flow the coolant fluid along the flow path such that the coolant fluid flows along the first channel 310 and the second channel 312. As the coolant fluid flows along the first channel 310 and the second channel 312, the coolant fluid may absorb heat from the tubular member 302 such that the tubular member 302 is cooled. In this manner, the tubular member 302 may be maintained at a safe temperature to avoid damage to the surrounding tissue.

[0102] During operation of the electrosurgical instrument 306, the coolant fluid source 314 may be configured to continuously flow coolant fluid along the flow path such that heat is continuously removed from the tubular member 302. The flow rate of coolant fluid along the flow path may be adjusted (e.g., by controlling the coolant fluid source 314) to control the cooling of the tubular member 302, such that the tubular member 302 may be maintained at a desired temperature.

[0103] The exhausted coolant fluid may then exit via a second conduit 320, as indicated by arrow 322. The coolant fluid exiting via the second conduit 320 may be captured, for example, in a reservoir for exhausted coolant fluid. As another example, the coolant fluid exiting via the second conduit 320 may be recirculated to the coolant fluid source 314 so that the coolant fluid may be reused.

[0104] Together, the electrosurgical instrument 306 and the introducer 300 may form part of an electrosurgical system, which is one embodiment of the present invention. Such an electrosurgical system may further include an electrosurgical generator connected (or connectable) at the proximal end of the transmission line 324 and configured to deliver RF and / or microwave energy to the transmission line 324.

[0105] 4 and 5 illustrate tubular members including different configurations of channels that may be used to circulate a coolant fluid. FIG. 4 illustrates a cross-sectional view of a tubular member 402 that may form a portion of an introducer according to an embodiment of the present invention. The tubular member 402 is formed by a hollow tubular tube of thermally conductive material. The tubular member 402 defines a lumen 404 extending along the length of the tubular member 402 through which an electrosurgical instrument may be inserted. A first pair of channels 406a, 406b and a second pair of channels 408a, 408b are defined in a sidewall 410 of the tubular member 402.

[0106] Similar to the first channel 310 and the second channel 312 discussed above, the channels 406a, 406b, 408a, and 408b extend along the length of the tubular member 402, i.e., from a proximal end of the tubular member 402 to a location near the distal end of the tubular member 402. The first pair of channels 406a, 406b may be fluidly connected to the second pair of channels 408a, 408b via a set of connecting channels (not shown) defined in a sidewall 410 of the tubular member 402 near the distal end of the tubular member 402. For example, a first connecting channel may be disposed to connect channel 406a to channel 408a, and a second connecting channel may be disposed to connect channel 406b to channel 408b.

[0107] The first pair of channels 406a, 406b may be used as an "inward channel" through which coolant fluid may be introduced into the tubular member 402, while the first pair of channels 408a, 408b may be used as an "outward channel" through which coolant fluid may exit the tubular member 402. For example, a coolant fluid source (e.g., similar to the coolant fluid source 314) may be connected to the proximal end of the first pair of channels 406a, 406b through a pair of conduits, and such coolant fluid may flow from the coolant fluid source into the first pair of channels 406a, 406b. The coolant fluid may then flow along the first pair of channels 406a, 406b toward the distal end of the tubular member 402. At the distal end of the tubular member 402, coolant fluid may be passed into the second pair of channels 408a, 408b via a set of connecting channels and then flow back toward the proximal end of the tubular member 402 where the coolant fluid may exit the tubular member 402. Similar to the above discussion of the first channel 310 and the second channel 312, as the coolant fluid flows through channels 406a, 406b, 408a, and 408b, heat may be removed from the tubular member 402 (and thus from the electrosurgical instrument received within the lumen 404).

[0108] The first pair of channels 406a, 406b are disposed at diametrically opposed locations within the sidewall 410 relative to the longitudinal axis of the tubular member 402. Similarly, the second pair of channels 408a, 408b are disposed at diametrically opposed locations within the sidewall 410 relative to the longitudinal axis of the tubular member 402. Such a configuration may lead to more uniform heat removal around the circumference of the tubular member.

[0109] 5 illustrates a cross-sectional view of a tubular member 502 that may form a portion of an introducer according to an embodiment of the present invention. The tubular member 502 is formed from a hollow tubular tube of thermally conductive material. The tubular member 502 defines a lumen 504 extending along the length of the tubular member 502, through which an electrosurgical instrument may be inserted.

[0110] A pair of concentric channels are defined within a sidewall 510 of the tubular member 502. Specifically, the tubular member 502 includes a first annular channel 506 concentrically disposed about a lumen 504 and a second annular channel 508 concentrically disposed about the first annular channel 506. The first annular channel 506 is separated from the lumen 504 by an inner wall 512. The inner wall 512 also serves to define the lumen 504. The first annular channel 506 is separated from the second annular channel 508 by a separation wall 514. The first annular channel 506 and the second annular channel 508 extend along the length of the tubular member 502, i.e., from a proximal end of the tubular member 502 to a location near the distal end of the tubular member 502. The first annular channel 506 and the second annular channel 508 are connected together near the distal end of the tubular member, for example, via one or more connecting passages formed in the separation wall 514. In this manner, the first annular channel 506 and the second annular channel 508 define a flow path along which a coolant fluid may be flowed.

[0111] For example, the first annular channel 506 may include an inlet (not shown) disposed near the proximal end of the tubular member 502. A coolant fluid source (e.g., similar to the coolant fluid source 314) may be connected to the inlet of the first annular channel 506, such that coolant fluid may flow from the coolant fluid source into the first annular channel 506. The coolant fluid may then flow along the first annular channel 506 toward the distal end of the tubular member 502. At the distal end of the tubular member 502, the coolant fluid may pass through a connecting passage in the separation wall 514 into the second annular channel 508. The coolant fluid may flow back along the second annular channel 508 toward the proximal end of the tubular member 502. The coolant fluid may exit the second annular channel 508 via an outlet of the second annular channel 508 located near the proximal end of the tubular member 502. As the coolant fluid flows along the first and second annular channels 506, 508, heat may be removed from the tubular member 502 (and thus from the electrosurgical instrument received within the lumen 504). In an alternative configuration, an inlet connected to the second annular channel 508 and an outlet may be connected to the first annular channel 506 such that coolant fluid may be introduced from a coolant fluid source into the second annular channel 508 and the coolant fluid may exit via the first annular channel 506.

[0112] Because the first annular channel 506 and the second annular channel 508 are arranged concentrically around the lumen 504, heat may be removed from the tubular member 502 by the coolant fluid in a substantially uniform manner around the longitudinal axis of the tubular member 502.

[0113] Figure 6 is a schematic diagram of an introducer 600 according to another embodiment of the present invention. The introducer 600 includes a tubular member 602 formed with a proximal portion 602a and a distal portion 602b joined together. The tubular member 602 defines a lumen 604 through which an electrosurgical instrument can be inserted. For purposes of illustration, the electrosurgical instrument is not shown in Figure 6.

[0114] Both the proximal portion 602a and the distal portion 602b of the tubular member 602 are formed of a thermally conductive material. The proximal portion 602a of the tubular member 602 is flexible (e.g., bendable and / or pliable), while the distal portion 602b of the tubular member 602 is rigid. In particular, the distal portion 602b may be formed of a material having a higher rigidity than the proximal portion 602a. For example, the distal portion 602b may be formed of a hollow cylindrical metal tube (e.g., formed of aluminum, copper, or brass), while the proximal portion 602a may be formed of a braided metal sleeve. The bond between the proximal portion 602a and the distal portion 602b is configured to conduct heat such that heat may flow between the proximal portion and the distal portion. For example, the proximal portion 602a and the distal portion 602b may be welded together.

[0115] The lumen 604 extends through both the proximal and distal portions 602a, 602b of the tubular member such that an electrosurgical instrument may be inserted through the tubular member 602. The lumen 604 is dimensioned such that when the electrosurgical instrument is inserted through the lumen 604, an outer surface of the electrosurgical instrument contacts the walls of the lumen 604. In this manner, the electrosurgical instrument may be thermally coupled to the tubular member 602 when the electrosurgical instrument is inserted within the tubular member 602 such that heat may flow from the electrosurgical instrument to the tubular member 602.

[0116] The pointed distal end 608 is secured to the distal end of the distal portion 602b of the tubular member 602. The pointed distal end 608 may be formed of a dielectric material, such as PEEK. The rigid distal portion 602b may facilitate percutaneous insertion of the distal portion 602b into a patient. The pointed distal end 608 may serve to pierce the patient's skin to further facilitate percutaneous insertion. Meanwhile, the flexible proximal portion 602a may allow the transmission line of the electrosurgical instrument to bend, which may facilitate handling of the electrosurgical instrument. For example, allowing the transmission line of the electrosurgical instrument to bend within the proximal portion 602a of the tubular member may facilitate connecting the transmission line to an electrosurgical generator.

[0117] The introducer 600 further includes a heat sink 612 thermally coupled to the proximal portion 602a of the tubular member 602 via a heat pipe 614. The introducer also includes a fan 616 configured to blow air over the heat sink 612 (as indicated by arrow 618) to actively cool the heat sink 612. The heat pipe 614, heat sink 612, and fan 616 may function in a manner similar to the heat pipe 214, heat sink 212, and fan 216 of the introducer 200 described above. In this manner, heat from the tubular member 602 may flow through the heat pipe 614 into the heat sink 612, which is cooled by the fan 616. Heat from the distal portion 602b of the tubular member may flow into the proximal portion 602a, which is then removed via the heat pipe 614. As a result, tubular member 602 may be maintained at a relatively low temperature, thereby avoiding damage to surrounding tissue. This may also allow for efficient removal of heat from an electrosurgical instrument received in lumen 604, thereby allowing the electrosurgical instrument to be maintained at a proper operating temperature.

[0118] In other embodiments, the heat sink 612 may be thermally coupled to the distal portion 602b instead of the proximal portion 602a. The heat pipes 614, the heat sink 612, and the fan 616 together may form a cooling assembly for the introducer 600.

[0119] 7 is a schematic diagram of an introducer 700 according to another embodiment of the present invention. Introducer 700 is similar in construction to introducer 200 described above, except that tubular member 702 of introducer 700 includes multiple layers formed of different materials.

[0120] The tubular member 702 of the introducer 700 includes an inner layer 704 concentric with an outer layer 706. The inner layer 704 is formed of a thermally conductive material, and the outer layer 706 is formed of a thermally insulating material. In one embodiment, the outer layer 706 is formed by a hollow cylindrical tube of thermally insulating material, such as mica. The tube of thermally insulating material may have a wall thickness of about 0.2 mm. The inner layer 704 may thus be formed as a coating of a thermally conductive material (e.g., gold) deposited on the inner wall of the hollow cylindrical tube. The coating of thermally conductive material may have a thickness of about 0.05 mm, such that the overall wall thickness of the tubular member 702 is 0.25 mm. A biocompatible coating may also be applied to the outer surface of the outer layer 706.

[0121] The tubular member 702 defines a lumen 708 through which an electrosurgical instrument 710 can be inserted. The lumen 708 is defined by an inner surface of the inner layer 704. The lumen 708 is dimensioned such that when the electrosurgical instrument 710 is received within the lumen 708, an outer surface of the electrosurgical instrument 710 contacts an inner surface of the inner layer 704. For example, a cross-sectional area of ​​the lumen 708 may match a cross-sectional area of ​​the electrosurgical instrument 710. In this manner, the electrosurgical instrument 710 may be thermally coupled to the inner layer 704 such that heat may flow from the electrosurgical instrument 710 to the inner layer 704. The electrosurgical instrument 710 includes a transmission wire 712 and an emitting tip 714, and is similar in configuration to the electrosurgical instrument 106 discussed above.

[0122] A pointed distal tip 716, formed from a dielectric material (e.g., PEEK), is provided at the distal end of tubular member 702. In some cases, pointed distal tip 716 may be formed from the same material as outer layer 706. For example, both outer layer 706 and pointed distal tip 716 may be formed from mica. In such an embodiment, pointed distal tip 716 may be integrally formed with outer layer 706.

[0123] The introducer 700 further includes a heat sink 718 thermally coupled to the proximal end of the tubular member 702 via a heat pipe 720. The introducer 700 also includes a fan 722 configured to blow air over the heat sink 718 (as indicated by arrow 724) to actively cool the heat sink 718. The heat pipe 720, heat sink 718, and fan 722 may function in a manner similar to the heat pipe 214, heat sink 212, and fan 216 of the introducer 200 described above. In this manner, heat from the tubular member 702 may flow through the heat pipe 720 into the heat sink 718, which is cooled by the fan 722.

[0124] The heat pipes 720 are connected (i.e., thermally coupled) to the inner layer 704 of the tubular member 702 through holes 726 formed in the outer layer 706. In this manner, heat may flow directly from the inner layer 704 to the heat sink 718 through the heat pipes 720, thereby efficiently removing heat from the inner layer 704. The heat pipes 720 may also be connected to the outer layer 706, such that heat from both the inner layer 704 and the outer layer 706 may flow through the heat pipes 720 to the heat sink 718.

[0125] Because the thermal conductivity of the inner layer 704 is greater than that of the outer layer 706, heat may flow preferentially along the inner layer 704. In this manner, the outer layer 706 may act as a thermal barrier between the electrosurgical instrument 710 and the surrounding tissue. Thus, the tubular member 702 may allow heat from the electrosurgical instrument 710 to be efficiently removed through the inner layer 704 of the tubular member 702 while minimizing heating of the surrounding tissue. The concept of a tubular member having a thermally conductive inner layer and an insulating outer layer may be applied to any of the other embodiments described herein.

[0126] The electrosurgical instrument 710 and the introducer 700 together may form part of an electrosurgical system, which is one embodiment of the present invention.

[0127] In the embodiments discussed above, various configurations of cooling assemblies have been described. In further embodiments, features of the various cooling assemblies discussed above may be combined to further enhance heat removal from the tubular member.

[0128] In the embodiments discussed above, the introducer may be used for percutaneous surgery, for example, where the tubular member of the introducer is percutaneously inserted into the patient's body. However, the above embodiments may be adapted such that they are suitable for use with a surgical examination device, such as a laparoscope. For example, the tubular member of the introducer of the above embodiments may be dimensioned such that it fits into the working channel of the surgical examination device. Furthermore, the tubular member may be provided without a sharp distal end to avoid damage to the surgical examination device.

Claims

1. 1. An introducer for introducing an electrosurgical instrument into a patient's body, comprising: a tubular member defining a lumen through which the electrosurgical instrument is insertable; and a cooling assembly configured to remove heat from the tubular member; Equipped with the cooling assembly includes a heat sink thermally coupled to the tubular member, the heat sink being formed of a thermally conductive material and having a higher heat capacity than the tubular member; The introducer, wherein the tubular member includes an inner layer formed of a thermally conductive material and an outer layer formed of a thermally insulating material.

2. The introducer of claim 1 , wherein the heat sink is located at or near a proximal end of the tubular member.

3. An introducer according to claim 1 or claim 2, wherein the heat sink is provided within a handle of the tubular member.

4. 4. An introducer according to any one of claims 1 to 3, wherein the heat sink is thermally coupled to the tubular member via a heat pipe.

5. An introducer according to any one of claims 1 to 4, wherein the cooling assembly is configured to actively cool the heat sink.

6. The introducer of claim 5 , wherein the cooling assembly includes a fan configured to actively cool the heat sink.

7. 7. An introducer according to claim 5 or claim 6, wherein the cooling assembly is configured to actively cool the heat sink with a coolant fluid.

8. 8. An introducer according to any one of claims 5 to 7, wherein the cooling assembly includes a heat exchanger configured to actively cool the heat sink.

9. An introducer according to any preceding claim, wherein the cooling assembly includes a heat pump configured to remove heat from the tubular member.

10. 10. An introducer as described in any one of claims 1 to 9, wherein the tubular member includes one or more channels defined on or in a side wall of the tubular member, and the cooling assembly is configured to circulate a coolant fluid through the one or more channels to remove heat from the tubular member.

11. The introducer of any one of claims 1 to 10, wherein the tubular member includes one or more contact elements disposed within the lumen and positioned to bear against an outer surface of the electrosurgical instrument when the electrosurgical instrument is inserted through the lumen.

12. An introducer according to any preceding claim, wherein the tubular member includes a distal end formed from a dielectric material.

13. An introducer according to any preceding claim, wherein the tubular member includes a pointed distal end.

14. An introducer according to any preceding claim, wherein the tubular member includes an outer layer formed from a biocompatible material.

15. An introducer according to any preceding claim, wherein a proximal portion of the tubular member is flexible and a distal portion of the tubular member is rigid.

16. An introducer according to any one of claims 1 to 15, wherein the length of the tubular member is 30 cm or more.

17. 1. An electrosurgical system comprising:

1. An electrosurgical instrument comprising: a transmission line for transporting microwave and / or radio frequency electromagnetic (EM) energy; and a radiating tip attached to a distal end of the transmission line configured to receive and deliver the microwave and / or radio frequency EM energy to biological tissue; the electrosurgical instrument comprising:

17. An introducer according to any one of claims 1 to 16, wherein the electrosurgical instrument is insertable through the lumen of the tubular member; The electrosurgical system comprises:

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