Electrosurgical instruments

Abstract

To provide an electrosurgical instrument having a radiation tip with improved flexibility.SOLUTION: In a first aspect, this is achieved by forming a dielectric material at a radiation tip 212 in order to facilitate bending of the radiation tip. In a second aspect, this is achieved by forming a dielectric body at the radiation tip and an outer sheath 230 as separate components, and by enabling movement between the components and bending. The operability of an electrosurgical instrument 200 can be improved by improving the flexibility of the radiation tip.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an electrosurgical instrument for delivering microwave energy and / or radiofrequency energy to a biological tissue in order to excise a target tissue. The probe can be inserted through the channel of an endoscope or catheter, or can be used in laparoscopic surgery or open surgery. The instrument can be used in pulmonary or gastrointestinal applications, but is not limited thereto.

Background Art

[0002] Electromagnetic (EM) energy, particularly microwave and radiofrequency (RF) energy, has been found to be useful in electrosurgery in its ability to cut, coagulate, and excise body tissue. Typically, a device for delivering EM energy to body tissue includes a generator that includes an EM energy source, and an electrosurgical instrument connected to the generator for delivering the energy to the tissue. Conventional electrosurgical instruments are often designed to be inserted percutaneously into a patient's body. However, for example, when the target site is in a thin-walled portion of the moving lung or gastrointestinal (GI) tract, it can be difficult to place the instrument percutaneously within the body. Other electrosurgical instruments can be delivered to the target site by a surgical scope device (e.g., an endoscope) that can pass through a channel within the body (e.g., the airway, or the lumen of the esophagus or colon). This enables minimally invasive procedures, which can reduce the patient's mortality rate and intraoperative and postoperative complication rates.

Summary of the Invention

Problems to be Solved by the Invention

[0003] Tissue excision using microwave EM energy is based on the fact that the majority of biological tissue is composed of water. The soft tissues of human organs typically have a water content between 70% and 80%. Water molecules have a permanent electric dipole moment; that is, there is an imbalance of charge throughout the molecule. This imbalance of charge causes the molecule to rotate and move in response to the force generated by the time-varying applied electric field, as the electric dipole moment aligns with the polarity of the applied electric field. At microwave frequencies, rapid molecular vibrations generate frictional heat, and the magnetic field energy is dissipated in the form of heat. This is known as dielectric heating.

[0004] This principle is used in microwave ablation therapy, where water molecules in target tissue are rapidly heated by applying a localized electromagnetic field at microwave frequencies, leading to tissue coagulation and cell death. Microwave-emitting probes are known to be used to treat various conditions in the lungs and other organs. For example, in the lungs, microwave radiation can be used to treat asthma and to excise tumors or lesions.

[0005] RF EM energy can be used for cutting and / or coagulating biological tissues. RF energy cutting methods operate on the principle that when an electric current flows through the tissue matrix (assisted by the cellular ion content, i.e., sodium and potassium), the impedance to the flow of electrons through the tissue generates heat. When a pure sine wave is applied to the tissue matrix, sufficient heat is generated within the cells, causing the tissue's water to evaporate. This significantly increases the intracellular pressure, which the cell membrane cannot control, resulting in cell rupture. When this occurs over a wide area, the tissue is transversely cut.

[0006] RF coagulation works by applying a low-efficiency waveform to tissue, where cellular components are heated to approximately 65°C instead of evaporating. This dehydrates the tissue and further denatures the proteins in the blood vessel walls and the collagen that makes up the cell walls. Protein denaturation triggers the coagulation cascade. This acts as a stimulus, strengthening coagulation. At the same time, the collagen in the blood vessel wall denatures from rod-shaped molecules into coils, causing the blood vessel to constrict and shrink, providing anchor points for the blood clot and reducing the area it blocks. [Means for solving the problem]

[0007] Most broadly, the present invention provides an electrosurgical instrument having a radiating tip with improved flexibility. In a first aspect of the present invention, this can be achieved by forming a dielectric material on the radiating tip to facilitate bending of the radiating tip. In a second aspect of the present invention, this can be achieved by forming the dielectric and outer sheath of the radiating tip as separate components, allowing movement and bending between the components. By improving the flexibility of the radiating tip, the operability of the electrosurgical instrument can be improved.

[0008] The electrosurgical instruments of the present invention may be used to excise target tissue within the body. To efficiently excise the target tissue, the radiating tip needs to be positioned as close as possible (often inside) to the target tissue. To reach the target tissue (e.g., in the lungs), the device may need to be guided through passages (e.g., airways) and around obstacles in the body. Therefore, making the radiating tip more flexible can facilitate guiding the radiating tip to the target tissue. For example, if the target tissue is in the lungs, this can facilitate advancing the instrument along passages (e.g., bronchioles) that may be narrow and winding. By positioning the radiating tip as close as possible to the target tissue, irradiation of surrounding healthy tissue can be avoided or reduced.

[0009] According to a first aspect of the present invention, an electrosurgical instrument is provided comprising: a coaxial power supply cable for transmitting microwave energy and / or high-frequency energy, wherein the coaxial power supply cable has an inner conductor, an outer conductor, and a dielectric material separating the inner conductor and the outer conductor; and an energy delivery structure disposed at the distal end of the coaxial power supply cable for receiving microwave energy and / or high-frequency energy, wherein the energy delivery structure includes an elongated conductor electrically connected to the inner conductor and extending longitudinally beyond the distal end of the coaxial power supply cable; and a dielectric disposed around the elongated conductor, wherein the dielectric includes a cavity therein, the cavity being positioned adjacent to the elongated conductor to facilitate bending of the radiating tip.

[0010] The energy delivery structure may be configured to deliver only microwave energy or only high-frequency energy. In further embodiments, the energy delivery structure may be configured to deliver both microwave energy and high-frequency energy separately or simultaneously. The elongated conductor may be configured as an antenna for radiating microwave energy or as a means of providing an electrical connection to an active electrode for delivering high-frequency energy (for example, in combination with a return electrode connected to an outer conductor).

[0011] Electrosurgical instruments may be suitable for removing tissue from enclosed or hard-to-reach areas of the human body (e.g., the lungs or uterus). However, it should be understood that these instruments may also be used to remove tissue from other organs.

[0012] The coaxial power supply cable may be a conventional low-loss coaxial cable that can be connected at one end to an electrosurgical generator. In particular, the inner conductor may be an elongated conductor extending along the longitudinal axis of the coaxial power supply cable. The dielectric material may be arranged around the inner conductor, for example, the first dielectric material may have a channel through which the inner conductor extends. The outer conductor may be a sleeve made of a conductive material arranged on the surface of the dielectric material. The coaxial power supply cable is a cable An outer protective sheath may further be included for insulating and protecting the cable. In some examples, the protective sheath may be made of or coated with a non-adhesive material to prevent tissue from sticking to the cable. The radiating tip is located at the distal end of the coaxial feed cable and serves to deliver EM energy transmitted along the coaxial feed cable to the target tissue. The radiating tip may be permanently attached to the coaxial feed cable or detachably attached to the coaxial feed cable. For example, a connector may be provided at the distal end of the coaxial feed cable, which is configured to house the radiating tip and form the necessary electrical connection.

[0013] The dielectric may have channels for carrying elongated conductors. The apparatus can be assembled by passing the elongated conductors through the channels or by depositing the dielectric on the elongated conductors.

[0014] The dielectric may generally be cylindrical, but other shapes are also possible. The dielectric may be attached to the distal end of the coaxial feed cable. In some examples, the dielectric may include a protruding portion of the dielectric material of the coaxial feed cable that extends beyond the distal end of the coaxial feed cable. This simplifies the structure of the radiating tip and avoids reflection of EM energy at the boundary between the radiating tip and the coaxial feed cable. In other examples, a second dielectric material different from the dielectric material of the coaxial feed cable can be used to form the dielectric. The second dielectric material may be the same as or different from the dielectric material of the coaxial feed cable. The second dielectric material may be selected to improve impedance matching with the target tissue in order to improve the efficiency of microwave energy delivery to the target tissue. The dielectric may also include several different portions of the dielectric material that are selected and arranged to form a radiating profile in a desired manner. The dielectric may be fabricated or coated with a non-adhesive material (e.g., PTFE) to prevent tissue from sticking to it.

[0015] The dielectric extends longitudinally, i.e., parallel to the longitudinal axis of the coaxial power supply cable. An elongated conductor extends within a channel of the dielectric. The channel can be a passage extending through a portion of the dielectric. The elongated conductor can be any suitable conductor having an elongated shape. For example, the elongated conductor may be a wire, rod, or strip of conductive material extending within the dielectric. In some embodiments, the elongated conductor may be the distal portion of an internal conductor extending beyond the distal end of the coaxial power supply cable. In other words, the internal conductor can extend into the dielectric beyond the distal end of the coaxial power supply cable to form an elongated conductor. This makes it easier to form a radiating tip at the distal end of the coaxial power supply cable, as there is no need to connect a separate conductor to the distal end of the internal conductor.

[0016] The radiating tip can be configured to function as a microwave radiator, that is, to radiate microwave energy transmitted by the coaxial feed cable. In particular, the microwave energy carried from the coaxial feed cable to the radiating tip can be radiated along the length of the elongated conductor. The outer conductor can be terminated at the distal end of the coaxial feed cable such that the elongated conductor extends beyond the distal end of the outer conductor. In this way, the radiating tip can function as a microwave unipolar antenna. Thus, the microwave energy carried to the radiating tip can be radiated from the elongated conductor to the surrounding target tissue.

[0017] Additionally or alternatively, the radiating tip may be configured to cut or excise target tissue using RF energy. For example, the radiating tip may include a pair of exposed electrodes (e.g., bipolar RF electrodes) positioned to cut or excise target tissue. One of the electrodes may be electrically connected to an internal conductor (e.g., via an elongated conductor), and the other electrode may be electrically connected to an external conductor. In this way, the radio frequency energy is By transmitting to proximal and distal electrodes, biological tissue located between or around the electrodes can be cut and / or excised. In some cases, the radiating tip can be configured to deliver both microwave and RF energy individually or simultaneously. This can allow for rapid changes in the function of the electrosurgical instrument by switching or changing the application between RF and microwave energy.

[0018] Cavities can be formed in a portion of a dielectric material arranged around an elongated conductor; that is, cavities can be located in a portion of a dielectric material having a channel through which the elongated conductor extends. Cavities may be spaced apart from the channel in a transverse (e.g., radial) direction perpendicular to the longitudinal direction. For example, if the dielectric material is cylindrical, the channel may be substantially centered on the central axis of the cylinder, and cavities may be spaced radially apart from the channel. Cavities may be voids formed inside or on the surface of the dielectric material, for example, in areas where the dielectric material of the dielectric material is absent. For example, a cavity may be a depression or recess on the surface of the dielectric material. Cavities may be formed on the outer surface of the dielectric material. Alternatively, cavities may be formed on the inner surface of the dielectric material, for example, in the wall of a channel. When cavities are formed inside a dielectric material, cavities may be voids or pockets enclosed within the dielectric material.

[0019] Cavities can reduce the amount of material in the dielectric portion surrounding an elongated conductor. For example, a cavity can reduce the total lateral thickness of the material forming the dielectric in the dielectric portion surrounding an elongated conductor. This can potentially reduce the rigidity of the dielectric around the elongated conductor. Cavities can also function as bending points or bends that facilitate the bending of the dielectric. Thus, cavities can help increase the flexibility of the dielectric. This can facilitate the bending of the radiating tip, and then facilitate the guidance of electrosurgical instruments through narrow, winding passages in the body. This can allow the radiating tip to be positioned as close as possible to the target tissue to ensure efficient energy delivery to the target tissue. The volume of the cavity may be relatively small compared to the overall volume of the dielectric material. In this way, cavities can improve the flexibility of the dielectric without significantly affecting the impedance matching of the dielectric. Thus, the radiation profile of the radiating tip may not be significantly affected by the presence of the cavity.

[0020] A cavity can be empty (for example, it can be filled with air). In some cases, a deformable material can be filled into the cavity to improve the flexibility of the dielectric.

[0021] In some cases, multiple cavities may be formed in the dielectric. The cavities may be arranged along the length of the dielectric, for example, they may be spaced apart in the longitudinal direction. This can provide multiple bending points along the length of the dielectric, facilitating the bending of the dielectric along its length. The cavities may be arranged around the longitudinal axis of the dielectric. This can facilitate bending the dielectric in directions different from the longitudinal direction. Therefore, having multiple cavities can further improve the flexibility of the dielectric. The multiple cavities may be arranged at equal intervals, or they may be arranged in any way. The cavities may be arranged on the dielectric to facilitate bending of the dielectric in a particular direction. For example, by arranging cavities on the side of the dielectric, it is possible to facilitate bending of the dielectric toward that side, for example, by reducing the stiffness of the dielectric on the side with the cavities. Arranging multiple cavities around the longitudinal axis of the dielectric can facilitate bending of the dielectric in multiple directions.

[0022] Cavities may be formed during the manufacturing of a dielectric. For example, a dielectric may be molded to contain one or more cavities. Alternatively, cavities may be formed by drilling holes in the dielectric and / or by mechanically cutting a portion of the dielectric.

[0023] In some embodiments, the cavity may be formed by a lumen extending longitudinally in the dielectric. The dielectric may have an inner sleeve surrounding an elongated conductor (i.e., providing a channel through which the elongated conductor extends). The lumen may be spaced from the elongated conductor by the radial thickness of the inner sleeve. The lumen can extend along the whole or part of the dielectric to improve the flexibility of the dielectric. The lumen may be a passage or channel extending through a part of the dielectric. The lumen may be a closed lumen, i.e., formed inside the dielectric. Alternatively, the lumen may be an open lumen, i.e., formed on the surface of the dielectric. In some examples, the lumen may be parallel to the channel in the dielectric. In other examples, the lumen may have a helical shape such that it is wound around the channel in the dielectric. The lumen may have a circular cross-section, or it may have a cross-section of another shape. Advantageously, the lumen can be used to transmit wiring or other inputs through a radiating tip. The dielectric lumen may be continuous with the lumen of the coaxial power supply cable, thereby allowing the input to be supplied from the proximal end of the electrosurgical instrument to the radiating tip. For example, the lumen may be used to carry a fluid (e.g., a coolant for cooling the tip). The lumen may be used to carry control wires (e.g., to control a blade or other mechanism located at the distal end of the radiating tip).

[0024] There may be multiple lumens extending along the longitudinal direction of the dielectric (for example, multiple cavities). The lumens may be arranged so as to be spaced apart around the channel of the dielectric, for example, the lumens may be equally spaced around the channel. This may facilitate the bending of the radial tips relative to the longitudinal axis in multiple directions.

[0025] In some embodiments, the lumen can have an annular cross-section, surrounding a portion of the dielectric in which the channel is formed. In other words, the dielectric can include an inner portion in which a channel including the elongated conductor is formed, and an outer portion that forms a sleeve around the inner portion. The outer portion can be spaced apart from the inner portion to form a lumen therebetween. The outer portion can, for example, be spaced from the inner portion using a spacer. By providing a lumen having an annular cross-section surrounding the inner portion of the dielectric, a cavity can be effectively formed around the longitudinal axis of the dielectric. Thereby, the rigidity of the dielectric becomes substantially symmetric about the longitudinal axis, facilitating the bending of the dielectric with respect to the longitudinal axis, for example, such that there is no preferential bending direction. The lumen can be arranged such that its annular cross-section is substantially centered on the longitudinal axis of the dielectric, and as a result, the lumen is axially symmetric about the longitudinal axis. Thereby, the isotropy of the rigidity of the dielectric around the longitudinal axis can be further improved.

[0026] In some embodiments, the lumen can be disposed on the outer surface of the dielectric. For example, it can form a longitudinally extending groove on the outer surface of the dielectric. Thus, the lumen can be an open lumen on the outer surface of the dielectric. If the dielectric includes a plurality of cavities, a plurality of grooves can be formed on the outer surface. In addition to facilitating the bending of the radiation tip, the grooves can serve as an engagement mechanism. For example, the outer protective sheath of an electrosurgical instrument can have one or more protrusions that engage the grooves to fix the outer protective sheath to the radiation tip. In another example, the grooves can be used to guide the radiation tip along the instrument channel of a surgical scope device and / or to maintain a desired orientation of the radiation tip. The grooves on the surface of the dielectric can, for example, be used to grip the radiation tip in order to rotate the radiation tip.

[0027] In some embodiments, the cavity may be formed by a recess in the dielectric. The recess may be formed on the outer surface of the dielectric. The recess may be a depression or notch formed on the surface of the dielectric. The recess may function as a bending point or a bent portion of the dielectric. For example, it constitutes a region with lower resistance to bending compared to other regions of the dielectric (e.g., for example, because the thickness of the dielectric at the recess is thin). The length of the recess may be perpendicular to the longitudinal direction to facilitate bending of the dielectric in the longitudinal direction. A plurality of recesses may be formed in the dielectric to provide a plurality of bending points or bent portions. In this way, the bending of the dielectric can be promoted at a plurality of points along its length.

[0028] In some embodiments, the recess may be formed on the outer surface of the dielectric. In other embodiments, the recess may be formed on the inner surface of the dielectric, e.g., on the wall of a channel of the dielectric. If there are a plurality of recesses, some of the recesses may be formed on the outer surface and some of the recesses may be formed on the inner surface.

[0029] In some embodiments, the recess can form a groove extending around the dielectric. The groove may be formed on the outer surface of the dielectric. The groove can form a loop or a ring around the dielectric. In this case, the groove can be oriented in a direction perpendicular to the longitudinal direction. In other cases, the groove may have a spiral shape so as to be wound around the dielectric along the length of the dielectric. By forming a groove around the dielectric, the rigidity of the dielectric can be substantially symmetric about the longitudinal axis. This can facilitate bending the dielectric with respect to the longitudinal axis.

[0030] In some embodiments, the dielectric may include a corrugated surface, and recesses may be formed by the corrugations of the corrugated surface. The outer surface of the dielectric may be corrugated, and / or the inner surface (channel wall) may be corrugated. In some cases, both the outer and inner surfaces of the dielectric may be corrugated. For example, part of the dielectric may be formed by a corrugated tube or pipe of a certain length. A suitable corrugated tube or pipe can be made of PTFE, FEP, or PFA. The corrugated surface may include a series of waves or ridges arranged to form a series of peaks and valleys. Recesses may correspond to valleys formed between adjacent waves / ridges. Since the corrugated surface may include multiple waves, multiple recesses may be formed on the corrugated surface. As described above, recesses can function as bending points or bends in the dielectric. Corrugated tubes are widely available commercially. This can facilitate the low-cost and easy manufacture of flexible radiating tips.

[0031] In some embodiments, the radiating tip may further include an outer sheath positioned around the outer surface of the dielectric, the outer sheath separating it from the dielectric and allowing relative movement between the outer sheath and the dielectric. The outer sheath may help protect and isolate the radiating tip from the environment. The outer sheath may be made of or coated with a non-adhesive material (e.g., PTFE) to prevent tissue from sticking. The outer sheath may also be a sleeve of insulating material covering the outer surface of the dielectric. For example, the outer sheath may be formed by a heat-shrinkable tube of a certain length that is shrunk around the dielectric. The outer sheath is separated from the dielectric; that is, it is formed separately from the dielectric; i.e., it is formed as a separate component. Furthermore, there may be no adhesive or other means of fastening the outer sheath to the dielectric. The outer sheath may be held to the dielectric via a frictional force between the outer sheath and the dielectric. As a result, a small amount of relative movement between the outer surface of the dielectric and the outer sheath may be possible. In this way, when the dielectric is bent, the outer sheath can move relative to the surface of the dielectric to avoid stress accumulation in the outer sheath. For example, the outer sheath can "gather" around the inside of the dielectric's bend. Therefore, the outer sheath may not provide any significant resistance to the bending of the radiating tip, i.e., the outer sheath may not be able to significantly increase the stiffness of the radiating tip. Thus, by forming the outer sheath separately from the dielectric, the bending of the radiating tip can be facilitated. Furthermore, this avoids the concentration of stress at the interface between the dielectric and the outer sheath, which could lead to the breakdown of the dielectric and / or cracking of the outer sheath.

[0032] The outer sheath may be attached at one end to the distal end of the coaxial feed cable to fix its position relative to the coaxial feed cable. For example, the outer sheath may be attached to the protective sheath of the coaxial feed cable. In some cases, the outer sheath may be an extension of the protective sheath of the coaxial feed cable. For example, the outer sheath may be the distal portion of the protective sheath of the coaxial feed cable that extends beyond the distal end of the coaxial feed cable. If a cavity is formed on the outer surface of the dielectric, the outer sheath can serve to cover the cavity. In this way, the radiating tip can have a smooth outer surface despite the presence of a cavity in the dielectric.

[0033] The configuration of the outer sheath may provide an independent embodiment of the present invention. According to this embodiment, an electrosurgical device is provided comprising: a coaxial power supply cable for transmitting microwave energy and / or radio frequency energy, wherein the coaxial power supply cable has an inner conductor, an outer conductor, and a dielectric material separating the inner conductor and the outer conductor; and an energy delivery structure, wherein the energy delivery structure includes an elongated conductor electrically connected to the inner conductor and extending longitudinally beyond the distal end of the coaxial power supply cable for receiving microwave energy and / or radio frequency energy, wherein the energy delivery structure includes an elongated conductor electrically connected to the inner conductor and extending longitudinally beyond the distal end of the coaxial power supply cable; a dielectric disposed around the elongated conductor; and an outer sheath disposed around the outer surface of the dielectric, wherein the outer sheath is separated from the dielectric, allowing relative movement between the outer sheath and the dielectric.

[0034] Features of the first aspect of the present invention may be common to those of the second aspect of the present invention and will not be described again. In particular, the dielectric of the electrosurgical instrument of the second aspect of the present invention may include cavities (or a plurality of cavities) as described above in relation to the first aspect of the present invention.

[0035] Any embodiment of the first or second aspect of the present invention described above may include the following features.

[0036] In some embodiments, the dielectric may be formed of a first dielectric material, and the outer sheath may be formed of a second dielectric material different from the first dielectric material. The first and second dielectric materials may be selected to improve impedance matching of the radiating tip with respect to the target tissue. The first and second dielectric materials may also be selected to facilitate bending of the radiating tip. For example, the second dielectric material may have lower stiffness than the first dielectric material. This ensures that the outer sheath does not significantly increase the overall stiffness of the radiating tip.

[0037] In some embodiments, the first dielectric material may have a higher melting temperature than the second dielectric material. This allows the outer sheath to be formed by melting or shrinking the second dielectric material on the dielectric. For example, the outer sheath may be formed by a heat-shrinkable tube made of the second dielectric material. The heat-shrinkable tube can be placed on the dielectric and then shrunk on the dielectric by applying heat. Since the melting temperature of the first dielectric material is higher than that of the second dielectric material, the dielectric does not melt when the outer sheath is formed on it. This ensures a good fit of the outer sheath onto the dielectric while maintaining them as separate components to allow relative movement between them. This can facilitate the fabrication of the radiating tip.

[0038] In some embodiments, the first dielectric material may be polytetrafluoroethylene (PTFE), and the second dielectric material may be fluoroethylene propylene (FEP). PTFE has a higher melting temperature than FEP. FEP is generally softer than PTFE and can therefore be easily bent. Using this combination of materials, FEP can be melted onto the dielectric and then exposed. An outer sheath can be formed directly onto the dielectric by creating a side sheath (for example, using a mold). Alternatively, an outer sheath can be formed onto the dielectric using a heat-shrinkable tube of a certain length made of FEP.

[0039] In some embodiments, the outer sheath may include a distal tip positioned to cover the distal end of the dielectric. Thus, the outer sheath can cover both the outer surface (e.g., the side) and the distal end of the dielectric. In this way, the outer sheath can form a cap on the dielectric. The distal tip may be made of the same dielectric material as the rest of the outer sheath (e.g., a second dielectric material). The distal tip may be pointed to facilitate insertion of the radiating tip into the target tissue. Alternatively, the distal tip may be rounded or flat. The distal tip may help improve impedance matching with the target tissue. The distal tip may also function to prevent fluid present in the environment surrounding the radiating tip from entering the space (e.g., cavity) between the outer sheath and the dielectric.

[0040] In some embodiments, the outer sheath may be configured to form a seal around the outer surface of the dielectric. Thus, the outer sheath can enclose the outer surface of the dielectric. The outer sheath can function to prevent fluids present in the environment surrounding the radiating tip from entering the space between the outer sheath and the dielectric. For example, the seal may be formed between the outer sheath and the dielectric at the proximal and distal ends of the dielectric. If the outer sheath includes a distal tip, the seal may only be required at the proximal end of the dielectric. In some cases, a seal can be formed between the outer sheath and the distal end of the coaxial feed cable to prevent leakage at the interface between the coaxial feed cable and the radiating tip.

[0041] If the cavity is on the outer surface of the dielectric, the outer sheath can function to contain the air (or other fluid) within the cavity and prevent fluids from the surrounding environment from entering the cavity.

[0042] In some embodiments, the radiating tip may further include a dielectric choke. The dielectric choke is a piece of electrically insulating material attached to the outer conductor (for example, between the outer conductor and the proximal electrode) to reduce the propagation of EM energy reflected at the radiating tip back into the coaxial feed cable. This can reduce the amount by which the radiating profile of the radiating tip extends along the coaxial feed cable, providing an enhanced radiating profile.

[0043] A dielectric material may include a helical body through which an elongated conductor extends. In other words, a portion of the dielectric material is formed as a helix, and the helix is ​​wound over the length of the elongated conductor. Thus, a channel through which an elongated conductor extends can be formed by a coil of helical material. The helical shape of the dielectric material can facilitate its bending and provide substantially symmetrical rigidity about the dielectric material's longitudinal axis. The helical body acts as a helical spring, providing a high degree of flexibility to the radiating tip. Furthermore, the helical shape of the dielectric material can facilitate its return to its original shape after being bent. For example, after bending to pass through a winding passage, the elasticity of the dielectric material can cause the radiating tip to straighten again.

[0044] A helical dielectric may include a third independent embodiment of the present invention. According to this embodiment, a coaxial power supply cable for transmitting microwave energy and / or high-frequency energy, wherein the coaxial power supply cable has an inner conductor, an outer conductor, and a dielectric material separating the inner conductor and the outer conductor; and an energy delivery structure, wherein the energy delivery structure includes an elongated conductor electrically connected to the inner conductor and extending longitudinally beyond the distal end of the coaxial power supply cable, and the energy delivery structure includes an elongated conductor electrically connected to the inner conductor and extending longitudinally beyond the distal end of the coaxial power supply cable, and around the elongated conductor An electrosurgical instrument is provided, comprising a dielectric, the dielectric including a spiral body on which an elongated conductor extends, and a radiating tip.

[0045] The features of the first and second aspects of the present invention may be common to the third aspect of the present invention and will not be described again.

[0046] In some embodiments of the electrosurgical instrument of any aspect of the present invention described above, the energy delivery structure may include a proximal adjustment element and a distal adjustment element, each of which is electrically connected to an elongated conductor, and the proximal and distal adjustment elements are spaced longitudinally apart by the length of the elongated conductor. The dielectric may include a first dielectric spacer positioned between the proximal and distal adjustment elements.

[0047] The proximal adjustment element may be a piece of conductive material (e.g., metal) located near the proximal end of the radiating tip. The distal adjustment element may be a piece of conductive material (e.g., metal) located near the distal end of the radiating tip. Therefore, the distal adjustment element may be further from the distal end of the coaxial feed cable than the proximal adjustment element. Both the proximal and distal adjustment elements are electrically connected to an elongated conductor. For example, the proximal and distal adjustment elements may be positioned on or around the elongated conductor, respectively. The proximal and distal adjustment elements can be electrically connected to the elongated conductor by any suitable means. For example, the proximal and distal adjustment elements may be welded or soldered to the elongated conductor. In another example, the proximal and distal adjustment elements may be connected to the elongated conductor using a conductive adhesive (e.g., conductive epoxy). The proximal and distal adjustment elements are spaced longitudinally apart by the length of the elongated conductor. In other words, a portion of the elongated conductor is positioned between the proximal and distal electrodes. The proximal and distal tuning elements may be covered with a portion of the dielectric, thereby isolating / protecting them from the environment.

[0048] Proximal and distal tuners can help shape the microwave energy profile emitted by the radiating tip. In particular, the inventors have found that arranging longitudinally spaced tuners on an elongated conductor can help generate a radiation profile concentrated around the radiating tip. The radiation profile can have a nearly spherical shape. The tuners can also function to reduce the tail of the radiation profile that extends backward along the coaxial feed cable. In this way, the microwave energy delivered to the radiating tip is emitted from the radiating tip and can excise a distinct amount of surrounding target tissue around the radiating tip. The shape, size, and position of the tuners can be selected to obtain a desired microwave radiation profile.

[0049] The first dielectric spacer may be part of a dielectric positioned between a proximal adjustment element and a distal adjustment element. Channels in the dielectric may be formed partially or entirely in the first dielectric spacer. In some cases, the proximal adjustment element may be spaced apart from the distal end of the coaxial feed cable. In such cases, the dielectric may include a second dielectric spacer positioned between the distal end of the coaxial feed cable and the proximal adjustment element.

[0050] When a cavity is formed within the dielectric, the cavity may be formed in the first dielectric spacer. In some cases, the cavity may be formed in the second dielectric spacer. Alternatively, the cavity may be formed in both the first and second dielectric spacers. This can further improve the flexibility of the radiating tip.

[0051] If the radiating tip includes an outer sheath, the outer sheath may cover the outer surface of the first dielectric spacer. The outer sheath may be separated from the first dielectric spacer to allow relative movement between the outer sheath and the first dielectric spacer. If the dielectric also includes a second dielectric spacer, the outer sheath may also cover the outer surface of the second dielectric spacer. The outer sheath also covers the outer surfaces of the proximal and distal adjustment elements, protecting and isolating them from the environment.

[0052] In some embodiments of electrosurgical instruments according to any of the above-described aspects of the present invention, the energy delivery structure may comprise a distal electrode and a proximal electrode disposed on the surface of a dielectric, the distal electrode and the proximal electrode being physically separated from each other by an intermediate portion of the dielectric. The proximal electrode may be electrically connected to an outer conductor. The distal electrode may be electrically connected to an inner conductor via an elongated conductor.

[0053] Since the proximal and distal electrodes are electrically connected to an outer and inner conductor, respectively, they function as a bipolar RF electrode by receiving RF energy transmitted along the coaxial feed cable. In this way, by transmitting high-frequency energy to the proximal and distal electrodes, biological tissue located between or around the electrodes can be excised and / or coagulated. Furthermore, the longitudinal spacing between the proximal and distal electrodes allows them to act as poles of a bipolar antenna when microwave energy is transmitted along the coaxial feed cable. Thus, when microwave energy is transmitted along the coaxial feed cable, the radiating tip can act as a microwave bipolar antenna. The spacing between the proximal and distal electrodes may depend on the microwave frequency used and the load induced by the target tissue. Therefore, this configuration of the radiating tip allows for tissue treatment using both RF and microwave energy. The inventors also discovered that it is possible to change the device's radiation profile (also called the "excision profile") by switching between RF and microwave energy. In other words, the size and shape of the tissue volume removed by the electrosurgical instrument can be adjusted by switching between RF energy and microwave energy. This may allow the resection profile to be changed in situ without the need to change instruments during the surgical procedure.

[0054] The intermediate portion of the dielectric may be a dielectric spacer positioned between the proximal and distal electrodes. Channels in the dielectric may be formed partially or entirely in the intermediate portion of the dielectric.

[0055] If a cavity is formed in the dielectric, the cavity may be formed in the intermediate portion of the dielectric. If the radiating tip includes an outer sheath, the outer sheath may cover the outer surface of the intermediate portion of the dielectric. The outer sheath may be separated from the intermediate portion to allow relative movement between the outer sheath and the dielectric. The outer sheath may be positioned so as not to cover the proximal and distal electrodes, i.e., so that the proximal and distal electrodes are exposed on the surface of the radiating tip. The outer sheath may be positioned coplanar with the surfaces of the proximal and distal electrodes, resulting in the radiating tip having a smooth outer surface.

[0056] In some embodiments, the radiating tip may further include a tuning element mounted in the middle portion of the dielectric. The tuning element may help to shape the radiation profile and improve impedance matching between the radiating tip and the target tissue. The tuning element may comprise a conductor mounted within the middle portion of the dielectric, which is electrically connected to an elongated conductor. The tuning element may have dimensions selected to introduce capacitance to improve the coupling efficiency of the radiating tip. For example, the conductor may be a sleeve mounted around a portion of an elongated conductor located between the proximal and distal electrodes.

[0057] Any electrosurgical instrument according to any of the above embodiments of the present invention may form part of a complete electrosurgical system. For example, an electrosurgical system may include an electrosurgical generator configured to supply microwave energy and / or radio frequency energy, and a device connected to receive microwave energy and / or radio frequency energy from the electrosurgical generator. The present invention may include an electrosurgical instrument, which may further include a surgical scope device (e.g., an endoscope) having a flexible insertion cord for insertion into the patient's body, wherein the flexible insertion cord has an instrument channel extending along its length, and the electrosurgical instrument is sized to fit within the instrument channel.

[0058] In this specification, “microwave” can generally be used to indicate a frequency range of 400 MHz to 100 GHz, but preferably in the range of 1 GHz to 60 GHz. 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. In contrast, in this specification, “high frequency” or “RF” is used to indicate a frequency range at least three orders of magnitude lower, e.g., up to 300 MHz. Preferably, the RF energy has a frequency high enough to prevent nerve stimulation (e.g., above 10 kHz) and a frequency low enough to prevent tissue decolorization or thermal diffusion (e.g., below 10 MHz). The preferred frequency range for RF energy may be between 100 kHz and 1 MHz.

[0059] In this specification, the terms “proximal” and “distal” refer to the ends of the electrosurgical instrument that are far from and near the treatment site, respectively. Therefore, during use, the proximal end of the electrosurgical instrument is closer to the generator that provides RF and / or microwave energy, while the distal end is closer to the treatment site (i.e., the patient’s target tissue).

[0060] The term "conductive" is used herein to mean electrical conductivity unless the context clearly indicates otherwise.

[0061] As used herein, the term “longitudinal direction” refers to the direction parallel to the axis of the coaxial transmission line, along the length of the electrosurgical instrument. As used herein, the term “lateral direction” refers to the direction perpendicular to the longitudinal direction, for example, the direction radially outward from the longitudinal axis of the coaxial transmission line. The term “internal” means near the center of the instrument (e.g., the axis) in the radial direction. The term “external” means far from the center (axis) of the instrument in the radial direction.

[0062] The term "electrosurgery" is used in reference to instruments, devices, or tools used during surgery that utilize microwave and / or high-frequency electromagnetic (EM) energy.

[0063] Examples of the present invention are discussed below with reference to the accompanying drawings. [Brief explanation of the drawing]

[0064] [Figure 1] This is a schematic diagram of an electrosurgical system for tissue resection, which is an embodiment of the present invention. [Figure 2] This is a schematic cross-sectional side view of an electrosurgical instrument, which is an embodiment of the present invention. [Figure 3] This is a schematic cross-sectional side view of an electrosurgical instrument, which is another embodiment of the present invention. [Figure 4a] This is a schematic cross-sectional side view of an electrosurgical instrument, which is an embodiment of the present invention. [Figure 4b] Figure 4a is a cross-sectional view of the dielectric spacer of an electrosurgical instrument. [Figure 5a] This is a cross-sectional view of a dielectric spacer that can be used in an electrosurgical instrument according to an embodiment of the present invention. [Figure 5b] This is a cross-sectional view of a dielectric spacer that can be used in an electrosurgical instrument according to an embodiment of the present invention. [Figure 5c] This is a cross-sectional view of a dielectric spacer that can be used in an electrosurgical instrument according to an embodiment of the present invention. [Figure 6] This is a schematic cross-sectional side view of an electrosurgical instrument, which is another embodiment of the present invention. [Figure 7a]Figure 6 is a perspective view of the dielectric spacer of an electrosurgical instrument. [Figure 7b] Figure 6 is a perspective view of the dielectric spacer of an electrosurgical instrument. [Figure 8] Figure 2 shows the simulated radiation profile of an electrosurgical instrument. [Figure 9] Figure 6 shows the simulated radiation profile of an electrosurgical instrument. [Figure 10] This is a schematic cross-sectional side view of an electrosurgical instrument, which is another embodiment of the present invention. [Figure 11a] A perspective view of a dielectric spacer that can be used in an electrosurgical instrument according to an embodiment of the present invention is shown. [Figure 11b] A perspective view of a dielectric spacer that can be used in an electrosurgical instrument according to an embodiment of the present invention is shown. [Modes for carrying out the invention]

[0065] Figure 1 is a schematic diagram of a complete electrosurgical system 100 capable of supplying microwave and radiofrequency energy to the distal end of an invasive electrosurgical instrument. The system 100 comprises a generator 102 for controllably supplying microwave and / or radiofrequency energy. A suitable generator for this purpose is described in WO2012 / 076844, which is incorporated herein by reference. To measure the appropriate power level to be delivered, the generator may be configured to monitor the reflected signal returned from the instrument. For example, the generator may be configured to calculate the impedance observed at the distal end of the instrument in order to determine the appropriate power delivery level. The generator may be configured to supply power in a series of pulses that are tuned to match the patient's respiratory cycle, so that power is supplied when the lungs contract.

[0066] The generator 102 is connected to the interface joint 106 by an interface cable 104. If necessary, the interface joint 106 can house an instrument control mechanism, which can be operated by sliding a trigger 110, to control the longitudinal (forward and backward) movement of, for example, one or more control wires or push rods (not shown). If there are multiple control wires, the interface joint may have multiple sliding triggers to provide complete control. The function of the interface joint 106 is to combine inputs from the generator 102 and the instrument control mechanism into a single flexible shaft 112 extending from the distal end of the interface joint 106. In other embodiments, other types of inputs may also be connected to the interface joint 106. For example, in some embodiments, a fluid supply may be connected to the interface joint 106 so that the fluid can be delivered to the instrument.

[0067] The flexible shaft 112 can be inserted through the entire length of the instrument (working) channel of the endoscope 114. The flexible shaft 112 has a distal assembly 118 (not shown to scale in Figure 1) formed to protrude (for example, into the patient) at the distal end of the endoscope tube through the instrument channel of the endoscope 114. The distal end assembly includes an operating tip for delivering microwave energy and high-frequency energy into biological tissue. The configuration of the tip is described in detail below.

[0068] The structure of the distal assembly 118 may be configured to have the maximum outer diameter suitable for passing through the working channel. Typically, the diameter of the working channel of a surgical scope device (e.g., endoscope) is less than 4.0 mm (e.g., any one of 2.8 mm, 3.2 mm, 3.7 mm, or 3.8 mm). The length of the flexible shaft 112 may be 0.3 m or more (e.g., 2 m or more). In other examples, the distal assembly 118 may be placed on the distal end of the flexible shaft 112 after the shaft has been inserted through the working channel (and before the instrument cord is introduced into the patient). Alternatively, the flexible shaft 112 may be inserted into the working channel from the distal end before its proximal connection is made. In these arrangements, the distal end assembly 118 This allows the surgical scope device 114 to have dimensions larger than the working channel.

[0069] The system described above is one method of introducing a device into a patient's body. Other techniques are also possible. For example, the device can also be inserted using a catheter.

[0070] Figure 2 shows a cross-sectional side view of an electrosurgical instrument 200, which is an embodiment of the present invention. The electrosurgical instrument 200 is configured to excise biological tissue by radiating microwave energy into the tissue. The distal end of the electrosurgical instrument may correspond to, for example, the distal assembly 118 discussed above. The electrosurgical instrument 200 includes a coaxial feed cable 202 that can be connected at its proximal end to a generator (e.g., generator 102) for transmitting microwave energy. The coaxial feed cable may correspond to the interface cable 104 described above. The coaxial feed cable 202 includes an inner conductor 204 and an outer conductor 206 separated by a dielectric material 208. The coaxial feed cable 202 is preferably low-loss to microwave energy. A choke (not shown) may be provided on the coaxial feed cable 204 to inhibit the backpropagation of microwave energy reflected from the distal end, thereby limiting backheating along the device. The coaxial power supply cable 202 further includes a flexible protective sheath 210 positioned around the outer conductor 206 to protect the coaxial power supply cable. The protective sheath 210 can be made of an insulating material to electrically insulate the outer conductor 206 from its surroundings. The protective sheath 210 can be made of or coated with a non-adhesive material (e.g., PTFE) to prevent tissue from sticking.

[0071] The radiating tip 212 is formed at the distal end 214 of the coaxial power supply cable 202. The dashed line 215 in Figure 2 shows the interface between the coaxial power supply cable 202 and the radiating tip 212. The radiating tip 212 is configured to receive microwave energy carried by the coaxial power supply cable 202 and deliver that energy into biological tissue. The outer conductor 206 of the coaxial power supply cable 202 terminates at the distal end 214 of the coaxial power supply cable 202; that is, the outer conductor 206 does not extend into the radiating tip 212. The radiating tip 212 includes the distal portion 216 of the inner conductor 204 that extends beyond the distal end of the coaxial power supply cable 202. In particular, the distal portion 216 of the inner conductor 204 extends beyond the distal end of the outer conductor 206.

[0072] A proximal adjustment element 218, made of a conductive material (e.g., metal), is electrically connected to the distal portion 216 of the internal conductor 204 near the proximal end of the radiating tip 212. The proximal adjustment element 218 has a cylindrical shape and includes a channel 220 through which the distal portion 216 of the internal conductor 204 passes. The proximal adjustment element 218 can be fixed to the internal conductor 204, for example, using a conductive adhesive (e.g., conductive epoxy), or by soldering or welding. The proximal adjustment element 218 is mounted so that it is centered on the internal conductor 204, thereby being symmetrically positioned about the longitudinal axis of the internal conductor 204.

[0073] The distal adjustment element 222, made of a conductive material (e.g., metal), is electrically connected to the distal portion 216 of the internal conductor 204 near the distal end of the radiating tip 212. Thus, the distal adjustment element 222 is positioned further along the internal conductor 204 than the proximal adjustment element 218. The distal adjustment element 222 is separated from the proximal adjustment element by the length of the distal portion 216 of the internal conductor 204. Like the proximal adjustment element 218, the distal adjustment element has a cylindrical shape and includes a channel 224. As seen in Figure 2, the distal portion 216 of the internal conductor 204 extends into the channel 224. The distal portion 216 of the internal conductor 204 terminates at the distal end of the channel 224, i.e., it does not protrude beyond the distal adjustment element 222. The distal adjustment element 222 can be fixed to the internal conductor 204, for example, using a conductive adhesive (e.g., conductive epoxy), or by soldering or welding. Similar to the proximal adjustment element 218, the distal adjustment element 222 is mounted so that it is centered on the internal conductor 204.

[0074] Both the proximal adjustment element 218 and the distal adjustment element 222 have the same outer diameter. The outer diameters of the proximal adjustment element 218 and the distal adjustment element 222 may be slightly smaller than the outer diameter of the electrosurgical instrument 200. In the illustrated example, the distal adjustment element 222 is longer than the proximal adjustment element 218 in the longitudinal direction of the instrument. For example, the distal adjustment element 222 may be about twice as long as the proximal adjustment element 218. By making the distal adjustment element 222 longer than the proximal adjustment element 218, it becomes possible to concentrate the microwave radiation around the distal end of the radiation tip 212.

[0075] The distal portion 226 of the dielectric material 208 extends into the radiating tip 212 beyond the distal end 214 of the coaxial feed cable 202. The distal portion 226 of the dielectric material 208 functions as a spacer between the proximal adjustment element 218 and the distal end 214 of the coaxial feed cable 202. In some embodiments (not shown), the dielectric material 208 may terminate at the distal end 214 of the coaxial feed cable 202, and a separate spacer may be provided between the distal end 214 of the coaxial feed cable 202 and the proximal adjustment element 218. The dielectric spacer 228 is provided in the radiating tip 212 between the proximal adjustment element 218 and the distal adjustment element 222. The dielectric spacer 228 is a cylindrical piece of dielectric material having a central channel extending through it. Thus, the dielectric spacer 228 may also be a tube of dielectric material. The distal portion 214 of the internal conductor 204 extends through the channel of the dielectric spacer 228. The proximal surface of the dielectric spacer 228 is in contact with the proximal adjustment element 218, and the distal surface of the dielectric spacer 228 is in contact with the distal adjustment element 222. The dielectric spacer 228 has approximately the same outer diameter as the proximal and distal adjustment elements 218 and 222.

[0076] The microwave energy carried along the coaxial power supply cable 202 is radiated along the length of the distal portion 216 of the inner conductor 204, allowing for the excision of target tissue. The radiation profile of the electrosurgical instrument 200 is discussed below in relation to Figure 8.

[0077] The radiating tip 212 further includes an outer sheath 230 provided outside the radiating tip 212. The outer sheath 230 covers the dielectric spacer 228 and the proximal and distal adjustment elements 218, 222, forming the outer surface of the radiating tip 212. The outer sheath 230 can insulate the radiating tip 212 and protect it from the environment. Since the outer diameter of the outer sheath 230 is substantially the same as the outer diameter of the coaxial feed cable 202, the device has a smooth outer surface. In particular, the outer surface of the sheath 230 may be coplanar with the outer surface of the coaxial feed cable 202 at the interface 215. The outer sheath 230 is fixed at its proximal end to the distal end of the protective sheath 210. A seal is formed between the outer sheath 230 and the protective sheath 210 to prevent fluid from leaking into the device at the interface between the coaxial power supply cable 202 and the radiating tip 212. In some embodiments (not shown), the outer sheath 230 may be an extension of the protective sheath 210 of the coaxial power supply cable 202.

[0078] The outer sheath 230 includes a pointed distal tip 232 that covers the distal end of the radial tip 212. The distal tip 232 is connected to a sleeve portion 231 of the outer sheath 230 that covers the outer surface of the dielectric spacer 228. Thus, the outer sheath 230 forms a cap around the outside of the radial tip 212. The distal tip 232 may be pointed to facilitate insertion of the radial tip 212 into the target tissue. However, in other embodiments (not shown), the distal tip may be rounded or flat.

[0079] The dielectric spacer 228 and the distal portion 226 of the dielectric material 208 can together form the dielectric of the radiating tip 212. The outer sheath 230 (including the distal tip 232) is formed separately from the dielectric of the radiating tip. In particular, the outer sheath 230 is not attached to the dielectric of the radiating tip (e.g., via adhesive or otherwise). The outer sheath may also not be fixed to the proximal or distal adjustment elements 218, 222. Thus, the outer sheath 2 The 30 is held on the radiating tip 212 via a connection to the protective sheath 210 and via the frictional force between the outer sheath 230 and the dielectric of the radiating tip 212. As a result, a small amount of relative movement and bending may be possible between the outer sheath 230 and the dielectric of the radiating tip 212. The range of relative movement between the outer sheath 230 and the dielectric may depend on the relative stiffness (flexibility) of the outer sheath and the dielectric.

[0080] The bending ability of the dielectric can facilitate the bending of the radial tip 212, as the movement of the outer sheath 230 relative to the dielectric can allow for the relief of stress in the outer sheath 230 (for example, when the radial tip 212 is bent). For example, the outer sheath 230 can "gather" around the inside of the bend of the radial tip 212 and / or separate from the dielectric around the inside of the bend of the radial tip 212. Furthermore, by allowing relative movement between the outer sheath 230 and the dielectric of the radial tip 212, stress at the interface between the dielectric and the outer sheath 230 can be avoided.

[0081] The outer sheath 230 is made of a dielectric material having a lower melting temperature than the dielectric of the radiating tip 212. For example, the outer sheath 230 may be made of FEP, and the dielectric spacer 228 may be made of PTFE. The outer sheath may be formed by melting or shrinking the dielectric material of the outer sheath 230 on the dielectric. For example, the outer sheath 230 may be formed by a heat-shrinkable tube of a certain length. In this way, the outer sheath 230 may be formed directly on the dielectric of the radiating tip 212, while ensuring that the outer sheath 230 does not fuse with the dielectric during manufacturing. The outer sheath 230 may be formed integrally as a single piece, i.e., the sleeve portion 231 and the distal tip 232 may be formed as a single part. Alternatively, the sleeve portion 231 and the distal tip 232 may be formed separately and then assembled together.

[0082] Figure 3 shows a cross-sectional side view of an electrosurgical instrument 300, which is another embodiment of the present invention. The electrosurgical instrument 300 is configured to deliver both microwave and RF energy to the target tissue separately or simultaneously. The distal end of the electrosurgical instrument may correspond, for example, to the distal assembly 118 discussed above.

[0083] The electrosurgical instrument 300 includes a coaxial feed cable 302 that can be connected at its proximal end to a generator (e.g., generator 102) for transmitting microwave and RF energy. The coaxial feed cable 302 includes an inner conductor 304 and an outer conductor 306 separated by a dielectric material 308. The coaxial feed cable further includes a flexible protective sheath 310 positioned around the outer conductor 306 to protect the coaxial feed cable 302. The coaxial feed cable 302 may be similar to the coaxial feed cable 202 described above.

[0084] The radiating tip 312 is formed at the distal end of the coaxial power supply cable 302. The radiating tip 312 is configured to receive microwave and RF energy carried by the coaxial power supply cable 302 and deliver that energy into biological tissue. The radiating tip 312 includes a proximal electrode 314 located near the proximal end of the radiating tip 312 and a distal electrode 316 located near the distal end of the radiating tip 312. The proximal electrode 314 is a hollow cylindrical conductor that forms an exposed ring around the outer surface of the radiating tip 312. The proximal electrode 314 can be electrically connected to the outer conductor 306 of the coaxial power supply cable 302. For example, the proximal electrode 314 can be welded or soldered to the outer conductor 306. To ensure axial symmetry of the connection, the proximal electrode 314 can be electrically connected to the outer conductor 306 by a region of physical contact extending around the entire circumference of the outer conductor 306. The outer conductor 206 terminates at the proximal electrode 314; that is, it does not extend distally beyond the proximal electrode 314. In some embodiments (not shown), the proximal electrode may be the exposed distal portion of the outer conductor 306.

[0085] The distal electrode 316 is also a hollow cylindrical conductor that forms an exposed ring around the outer surface of the radiating tip 312. Like the proximal electrode 314, the distal electrode 316 is positioned coaxially with the coaxial power supply cable 302. The proximal and distal electrodes 314, 316 may have substantially the same shape and size. The distal electrode 316 is spaced apart from the proximal electrode 314 in the longitudinal direction of the electrosurgical instrument 300. The proximal and distal electrodes 314, 316 have the same outer diameter as the coaxial power supply cable 302, and as a result, the electrosurgical instrument 300 has a smooth outer surface. This prevents tissue from getting caught on the proximal and distal electrodes 314, 316.

[0086] The proximal electrode 314 defines a passage through which the distal projection of the internal conductor 304 passes. In this way, the internal conductor 304 extends into the radiating tip 312, where it is electrically connected to the distal electrode 316. The internal conductor 304 is electrically connected to the distal electrode 316 via a conductor 318 that extends radially (i.e., outward) from the internal conductor 306. The conductor 318 may include one or more branches (e.g., wires or other flexible conductive elements) arranged symmetrically around the axis of the internal conductor 304. Alternatively, the conductor 318 may include a conductive disk or ring mounted around the internal conductor 304 and connected between the internal conductor 304 and the distal electrode 316. The connection between the internal conductor 304 and the distal electrode 316 is preferably symmetrical around the axis defined by the internal conductor 204. This facilitates the formation of a symmetrical magnetic field shape around the radiating tip 312.

[0087] The distal portion of the dielectric material 308 of the coaxial power supply cable 302 also extends beyond the distal end of the outer conductor 306 into the radiating tip 312 via a passage defined by the proximal electrode 314. Thus, the inner conductor 304 and the proximal electrode 314 are insulated by the dielectric material 308. The distal portion of the dielectric material 308 forms the dielectric of the radiating tip 312. The tuning element 320 is located in the intermediate portion 322 of the dielectric of the radiating tip 312, situated between the proximal electrode 314 and the distal electrode 316. The tuning element 320 is a conductive element electrically connected to the inner conductor 304 between the proximal electrode 314 and the distal electrode 316 in order to introduce capacitive reactance. In this example, the conductive tuning element 320 is cylindrical and is positioned coaxially with the inner conductor 304. The tuning element 320 may help improve coupling efficiency (i.e., reduce reflected signals) when the instrument is operated at microwave frequencies.

[0088] Since the proximal electrode 314 and distal electrode 316 are electrically connected to the outer conductor 306 and inner conductor 304, respectively, they can be used as bipolar RF cutting electrodes. For example, the distal electrode 316 can function as the active electrode, and the proximal electrode 314 can function as the return electrode for RF energy transmitted along the coaxial power supply cable 302. In this way, target tissue positioned around the radiating tip 312 can be cut and / or coagulated using RF energy via the above mechanism.

[0089] Furthermore, when microwave energy is transmitted along the coaxial feed cable 302, the radiating tip 312 can act as a microwave bipolar antenna. In particular, the proximal electrode 314 and distal electrode 316 can function as radiating elements of the bipolar antenna at microwave frequencies. Thus, the structure of the radiating tip allows for the delivery of both radiofrequency and microwave energy into the target tissue. This allows for the use of radiofrequency and microwave energy to excise and / or coagulate the target tissue, depending on the type of EM energy transmitted to the radiating tip. The cylindrical shapes of the proximal electrode 314 and distal electrode 316 may function to produce a radiating profile that is symmetrical around the longitudinal axis of the instrument 300.

[0090] The radiating tip 312 includes an outer sheath 324. The outer sheath 324 covers the outer surface of the intermediate portion 322 of the dielectric material 308 between the proximal electrode 314 and the distal electrode 316. The outer sheath 324 is coplanar with the exposed surfaces of the proximal and distal electrodes 314, 316, and as a result, the radiating tip 312 has a smooth outer surface. The outer sheath 324 may function to protect and insulate the portion of the radiating tip 312 between the proximal electrode 314 and the distal electrode 316. The outer sheath 324 is formed separately from the dielectric material 308. In particular, the outer sheath 324 is not attached to the dielectric material 308 (e.g., via adhesive or otherwise). The outer sheath 324 can be held on the radiating tip 312 by the proximal and distal electrodes 314, 316, thereby blocking the longitudinal movement of the outer sheath 324 (since the proximal electrode 314, distal electrode 316 and outer sheath 324 all have the same outer diameter). The outer sheath 324 may also be held in place by frictional forces between the outer sheath 324 and the dielectric material 308. As a result, a small amount of movement and bending may be possible between the outer sheath 324 and the intermediate portion 322 of the dielectric material 308. The range of relative movement between the outer sheath 324 and the intermediate portion 322 may depend on the relative stiffness (flexibility) of the outer sheath 324 and the intermediate portion 322. The radial tip 312 further includes a distal tip 326 at its distal end. The distal tip is pointed to facilitate insertion of the radial tip 312 into the target tissue.

[0091] Similar to the apparatus 200, this configuration of the outer sheath 324 facilitates the bending of the radial tip 312. In particular, by allowing some movement between the outer sheath 324 and the intermediate portion 322 of the dielectric material 308, stresses within the outer sheath 324 that may occur when the radial tip is bent can be relieved. Stresses at the interface between the intermediate portion 322 and the outer sheath 324 can also be avoided.

[0092] The outer sheath 324 may be formed in a similar manner to the outer sheath 230 described above. For example, the outer sheath 324 may be made of FEP, which is melted or shrunk around the intermediate portion 322 of the dielectric material 208. The intermediate portion 322 of the dielectric material 208 may be made of a material having a higher melting temperature than FEP (e.g., PTFE), so as to not melt during the formation of the outer sheath 324.

[0093] The flexibility of the radiating tip of an electrosurgical instrument can also be increased by changing the shape of the dielectric material of the radiating tip. In particular, one or more cavities can be formed in the dielectric material of the radiating tip to facilitate bending.

[0094] Figure 4a shows a cross-sectional view of an electrosurgical instrument 400, which is an embodiment of the present invention. The electrosurgical instrument 400 is similar to the electrosurgical instrument 200 described above, except that its dielectric spacer includes an annular lumen through which it extends. The reference numerals used in Figure 2 are used in Figure 4a to indicate features of the electrosurgical instrument 400 that correspond to the features described above in relation to Figure 2.

[0095] The electrosurgical instrument 400 includes a dielectric spacer 401 at its radiating tip 212 between the proximal adjustment element 218 and the distal adjustment element 222. The dielectric spacer 401 is similar to the dielectric spacer 228 of the electrosurgical instrument 200, except that it includes an annular lumen 402 extending through it. The annular lumen 402 extends longitudinally along the length of the dielectric spacer 401. Figure 4b shows a cross-sectional view of the dielectric spacer 401 of the electrosurgical instrument 400 in a plane perpendicular to the longitudinal direction of the electrosurgical instrument 400. As shown, the annular lumen 402 has an annular (e.g., circular) cross-section surrounding the distal portion 216 of the internal conductor 204. The annular lumen 402 is formed between the inner portion 404 of the dielectric spacer 401 through which the distal portion 216 of the internal conductor extends, and the outer portion 406 of the dielectric spacer 401 which forms a sleeve around the inner portion 404. The annular lumen 402 is coaxially positioned around the distal portion 216 of the internal conductor 204. In other words, the annular lumen 402 is substantially symmetrical with respect to the longitudinal axis of the internal conductor 204.

[0096] The annular lumen 402 forms a cavity (or void) within the dielectric spacer 401, that is, This forms a tubular region within the dielectric spacer 401 where no dielectric material is present. The annular lumen 402 can be filled with air, for example. As a result, the amount of material in the dielectric spacer 401 is reduced (compared to, for example, the dielectric spacer 228 of the electrosurgical instrument 200). In particular, as shown in Figure 4b, the cross-sectional area of ​​the dielectric spacer 401 containing the dielectric material is reduced by an amount corresponding to the cross-sectional area of ​​the annular lumen 402. Generally, the stiffness of a body is proportional to the cross-sectional area of ​​the material forming that body. Therefore, by forming the annular lumen 402 in the dielectric spacer 228, the stiffness of the dielectric spacer 401 can be reduced, which can facilitate the bending of the dielectric spacer 401 along its length. Since the annular lumen 402 is positioned symmetrically about the longitudinal axis of the instrument, the stiffness of the dielectric spacer 401 can be substantially symmetric about the longitudinal axis. As a result, the bending of the dielectric spacer 401 can be facilitated in all directions in a plane perpendicular to the longitudinal axis.

[0097] Other types of lumens or cavities besides the annular lumen 402 shown in Figures 4a and 4b may be used to improve the flexibility of the radial tip. Figures 5a to 5c show cross-sectional views (in a plane perpendicular to the longitudinal axis) of dielectric spacers having different shapes of lumens extending through them. The dielectric spacers shown in Figures 5a to 5c can be replaced, for example, with the dielectric spacer 401 of the electrosurgical instrument 400.

[0098] Figure 5a shows a cross-sectional view of the dielectric spacer 500. The dielectric spacer 500 includes a central channel 502 through which the distal portion 216 of the internal conductor 204 can extend. The dielectric spacer 500 also includes three lumens 504, 506, and 508 arranged around the central channel 502. The lumens 504, 506, and 508 are arranged such that they are substantially rotationally symmetric about their longitudinal axis. The lumens 504, 506, and 508 can extend longitudinally along the length of the dielectric spacer 500. The lumens 504, 506, and 508 can be filled with air. Similar to the annular lumen 402, the lumens 504, 506, and 508 function to reduce the rigidity of the dielectric spacer 500 and improve the flexibility of the radiating tip.

[0099] Figure 5b shows a cross-sectional view of another dielectric spacer 510. The dielectric spacer 510 includes a central channel 512 through which the distal portion 216 of the internal conductor 204 can extend. The central channel 512 may have a larger cross-section than the distal portion 216 of the internal conductor 204, resulting in a space being formed between the wall of the central channel 512 and the distal portion 216. Thus, the central channel 512 can function as a cavity within the dielectric spacer 500 to reduce its rigidity. The dielectric spacer 510 also includes a series of open lumens 514-524 (or grooves) formed on its outer surface. The open lumens 514-524 are arranged such that they are substantially rotationally symmetric about their longitudinal axis. The open lumens 514-524 can reduce the rigidity of the dielectric spacer 510. Air can be trapped in the open lumens by an outer sheath (e.g., outer sheath 230) formed on the outer surface of the dielectric spacer.

[0100] Figure 5c shows a cross-sectional view of another dielectric spacer 526. Dielectric spacer 526 is similar to dielectric spacer 510 in that it includes a central channel 528 through which the distal portion 216 of the internal conductor 204 can extend, and a series of open tubular lumens 530-536 arranged on its outer surface. The open tubular lumens 530-536 are arranged such that they are substantially rotationally symmetric about their longitudinal axis.

[0101] The cavities or lumens do not need to extend along the entire length of the dielectric spacer. For example, the lumens or cavities may extend along only a portion of the dielectric spacer, or may have one or more radial support arms penetrating it. In some cases, there may be multiple lumens or cavities extending along different portions of the dielectric spacer. Different types of cavities or lumens can be combined within the dielectric spacer. The radial tips are specific If preferential flexibility in a particular direction is desired, a cavity or lumen may be positioned on the corresponding side of the dielectric spacer to reduce the rigidity of the spacer on that side. In some embodiments (not shown), a lumen can be formed in the distal portion 226 of the dielectric material 208 to improve the flexibility of the radiating tip 212 near the interface with the coaxial power supply cable 202. The cavities or lumen described above can be incorporated into other electrosurgical instruments to improve the flexibility of the radiating tip. For example, the electrosurgical instrument 300 described above may be modified so that the intermediate portion 322 of the dielectric material 308 includes one or more lumens extending through it.

[0102] Figure 6 shows a cross-sectional view of an electrosurgical instrument 600, which is another embodiment of the present invention. The electrosurgical instrument 600 is similar to the electrosurgical instrument 200 described above, except that its dielectric spacer is formed to improve its flexibility. The reference numerals used in Figure 2 are used in Figure 6 to indicate features of the electrosurgical instrument 600 that correspond to the features described above in relation to Figure 2.

[0103] The electrosurgical instrument 600 includes a dielectric spacer 602 at its radiating tip 212 between the proximal adjustment element 218 and the distal adjustment element 222. The dielectric spacer 602 has a generally cylindrical shape. The dielectric spacer 602 includes a channel 603 passing through its center, on which the distal portion 216 of the internal conductor 204 extends. A first annular groove 604 and a second annular groove 606 are formed on the outer surface of the dielectric spacer 602. The first groove 604 and the second groove 606 each form a loop around the outer surface of the dielectric spacer 602. Figure 7a shows a perspective view of the dielectric spacer 602, and Figure 7b shows a side view of the dielectric spacer 602. The first groove 604 and the second groove 606 form regions within the dielectric spacer 602 where the cross-sectional area of ​​the dielectric spacer 602 is reduced (for example, compared to the area of ​​the dielectric spacer 602 away from the grooves). Therefore, the dielectric spacer 602 may have lower rigidity in grooves 604 and 606 than outside the grooves, and as a result, the bending of the dielectric spacer 602 is promoted in grooves 604 and 606. Thus, the first groove and the second grooves 604 and 606 can function as bending points or bending portions of the dielectric spacer. Thus, the first groove and the second grooves 604 and 606 may help improve the flexibility of the radial tip portion 212.

[0104] The sleeve portion 231 of the outer sheath 230 covers the outer surface of the dielectric spacer 602. In this way, the first groove and the second grooves 604, 606 are covered by the outer sheath 230, and as a result, the radiating tip 212 has a smooth outer surface. Air can be trapped in the first groove and the second grooves 604, 606 by the outer sheath.

[0105] In other embodiments (not shown), more grooves can be provided on the outer surface of the dielectric spacer to provide further bending points in the dielectric spacer. To further improve the flexibility of the dielectric spacer, grooves may be formed on the inner surface of the dielectric spacer, for example, on the walls of a channel 603 through which the distal portion 216 of the internal conductor 204 extends. In the illustrated example, the first and second grooves 604, 606 have rectangular contours, i.e., they have side walls 608, 610 parallel to each other and an inner wall 612 perpendicular to the side walls 608, 610 (see Figure 7b). However, grooves of other shapes can also be used. For example, the side walls 608, 610 may be at an oblique angle to each other. In some cases, the grooves may have triangular or rounded contours. Combinations of grooves with different contours can be used on the same dielectric spacer. In some embodiments (not shown), grooves can be formed in the distal portion 226 of the dielectric material 208 to improve the flexibility of the radiating tip 212 near the interface with the coaxial power supply cable 202. The concept of forming grooves or recesses on the surface of the dielectric spacer can be incorporated into other electrosurgical instruments to improve the flexibility of the radiating tip. For example, the electrosurgical instrument 300 may be modified so that grooves are formed in the middle portion 322 of the dielectric material 308 to provide a bending point in the radiating tip 312.

[0106] Figure 8 shows the simulated radiation profile of the target tissue from the electrosurgical instrument 200. The radiation profile was simulated using finite element analysis software for a microwave frequency of 5.8 GHz. The radiation profile shows the volume resulting from the tissue excised by microwave energy. As seen in Figure 8, the radiation profile is concentrated around the radiation tip, defining a nearly spherical region.

[0107] Figure 9 shows the simulated radiation profile of the electrosurgical instrument 600 on target tissue. The radiation profile was simulated for a microwave frequency of 5.8 GHz using finite element analysis software. Similar to the radiation profile shown in Figure 8, the radiation profile of the electrosurgical instrument 600 is concentrated around the radiation tip, defining a nearly spherical region. The shape of the radiation profile of the electrosurgical instrument 600 is not significantly affected by the presence of the first and second grooves 604 and 606 in the dielectric spacer 602. Therefore, the first and second grooves 604 and 606 can improve the flexibility of the radiation tip without significantly affecting the radiation profile of the radiation tip.

[0108] Figure 10 shows a cross-sectional view of an electrosurgical instrument 700, which is another embodiment of the present invention. The electrosurgical instrument 700 is similar to the electrosurgical instrument 200 described above, except that its dielectric spacer is corrugated to improve its flexibility. The reference numerals used in Figure 2 are used in Figure 10 to indicate features of the electrosurgical instrument 700 that correspond to the features described above in relation to Figure 2.

[0109] The electrosurgical instrument 700 includes a dielectric spacer 702 at its radiating tip 212 between the proximal adjustment element 218 and the distal adjustment element 222. The dielectric spacer 702 is formed from a corrugated (or spiral) tube of a certain length. The corrugated tube of a certain length may be made of, for example, PTFE or PFA. The dielectric spacer 702 defines a channel (or passage) through which the distal portion of the internal conductor 204 extends. The corrugation on the outer surface of the dielectric spacer 702 defines a series of regularly spaced peaks (e.g., peaks 704, 706) and valleys (e.g., valley 708) located between the peaks. The valleys on the corrugated outer surface correspond to grooves or depressions on the outer surface of the dielectric spacer 702, i.e., regions where the dielectric spacer has a smaller outer diameter (e.g., compared to regions where peaks are located). Thus, the valleys (grooves) can function as inflection points or bends in the dielectric 702. Therefore, the corrugated outer surface of the dielectric spacer 702 provides a series of regularly spaced bending points that facilitate the bending of the dielectric spacer 702 along its length. This can result in a highly flexible radial tip 212.

[0110] The outer sheath 230 covers the corrugated outer surface of the dielectric spacer 702, and as a result, the radiating tip 212 has a smooth outer surface. Air can be trapped in the corrugation by the outer sheath 230. In some embodiments (not shown), the outer surface of the dielectric spacer may be smooth, and instead, the corrugation may be formed on the inner surface of the dielectric spacer (e.g., the wall of the channel through which the distal portion 216 of the inner conductor 204 extends). The concept of using a corrugated dielectric material for the radiating tip to increase the flexibility of the radiating tip can be incorporated into other electrosurgical instruments. For example, the electrosurgical instrument 300 can be modified so that the middle portion 322 of the dielectric material 308 has a corrugated surface, providing a series of bending points in the radiating tip 312.

[0111] Figures 11a and 11b show perspective views of a dielectric spacer 800 that may be used in an electrosurgical instrument according to an embodiment of the present invention. For example, the dielectric spacer 800 can replace the dielectric spacer 228 of an electrosurgical instrument 200. The dielectric spacer 800 has a helical body 802 made of a flexible dielectric material (e.g., PTFE) formed in a coil. The helical body 802 extends along its axis and has an elongated conductor (e.g., the distal portion 216 of the internal conductor 208) This defines a passage 804 that can extend through. Due to its helical shape, the dielectric spacer 800 can behave like a helical spring. In particular, the helical shape of the dielectric spacer 800 facilitates the bending of the dielectric spacer 800 with respect to its longitudinal axis. Therefore, by incorporating the dielectric spacer 800 into the radiating tip of an electrosurgical instrument, the bending of the radiating tip can be facilitated. The helical shape of the dielectric spacer can also enhance the elasticity of the dielectric spacer 800. The dielectric spacer 800 can help straighten the radiating tip after it has been bent. For example, after the radiating tip is bent and passes through a winding passage, the elasticity of the dielectric spacer 800 can act to straighten the radiating tip. In this way, the radiating tip can automatically return to its original (e.g., straight) configuration after being bent.

[0112] In some embodiments (not shown), only a portion of the dielectric spacer may have a helical shape. The concept of using a helical dielectric material at the radiating tip to facilitate bending of the radiating tip can be incorporated into other electrosurgical instruments. For example, the electrosurgical instrument 300 may be modified so that the intermediate portion 322 of the dielectric material 308 includes a helical portion to facilitate bending of the radiating tip 312.

Claims

1. It is an electrosurgical instrument, A coaxial power supply cable for transmitting microwave energy and / or high-frequency energy, wherein the coaxial power supply cable has an inner conductor, an outer conductor, and a dielectric material separating the inner conductor and the outer conductor, A radiating tip positioned at the distal end of the coaxial power supply cable for receiving the microwave energy and / or the high-frequency energy, wherein the radiating tip is An energy delivery structure configured to deliver microwave energy and / or high-frequency energy received from the coaxial power supply cable from the outer surface of the radiating tip, wherein the energy delivery structure includes an elongated conductor electrically connected to the internal conductor and extending longitudinally beyond the distal end of the coaxial power supply cable, A dielectric comprising a channel, wherein the elongated conductor extends into the channel such that the dielectric is positioned around at least a portion of the elongated conductor, An outer sheath including a sleeve of insulating material covering the outer surface of the dielectric, wherein the outer sheath is separated from the dielectric to allow relative movement between the outer sheath and the dielectric, and the radiating tip includes the outer sheath, The electrosurgical instrument comprising the above-mentioned equipment.

2. The electrosurgical instrument according to claim 1, wherein the dielectric is formed of a first dielectric material, and the outer sheath is formed of a second dielectric material different from the first dielectric material.

3. The electrosurgical instrument according to claim 2, wherein the first dielectric material has a higher melting temperature than the second dielectric material.

4. The electrosurgical instrument according to claim 3, wherein the first dielectric material is polytetrafluoroethylene and the second dielectric material is fluoroethylene propylene.

5. The electrosurgical instrument according to any one of claims 1 to 4, wherein the outer sheath includes a distal tip portion that is arranged to cover the distal end of the dielectric.

6. The electrosurgical instrument according to any one of claims 1 to 5, wherein the outer sheath is configured to form a seal around the outer surface of the dielectric.

7. The electrosurgical instrument according to any one of claims 1 to 6, wherein the dielectric includes a helical body through which the elongated conductor extends.

8. The electrosurgical instrument according to any one of claims 1 to 6, wherein the dielectric includes a cavity therein, and the cavity is formed in a part of the dielectric that is arranged around the elongated conductor to facilitate the bending of the radiating tip.

9. The energy delivery structure includes a proximal adjustment element and a distal adjustment element for forming the radiation profile of the energy delivery structure, each of which includes a conductive material electrically connected to the elongated conductor, and the proximal adjustment element and the distal adjustment element are spaced apart in the longitudinal direction by the length of the elongated conductor. The electrosurgical instrument according to any one of claims 1 to 8, wherein the dielectric includes a first dielectric spacer disposed between the proximal adjustment element and the distal adjustment element.

10. The energy delivery structure comprises a distal electrode and a proximal electrode disposed on the surface of the dielectric, the dielectric comprises an intermediate portion located between the distal electrode and the proximal electrode, and the intermediate portion physically separates the distal electrode and the proximal electrode from each other. The proximal electrode is electrically connected to the outer conductor, The electrosurgical instrument according to any one of claims 1 to 8, wherein the distal electrode is electrically connected to the internal conductor via the elongated conductor.

11. The electrosurgical instrument according to claim 10, further comprising an adjustment element attached to the intermediate portion of the dielectric, wherein the adjustment element is configured to form a radiation profile of the energy delivery structure, and the adjustment element comprises a conductor electrically connected to the elongated conductor.

12. An electrosurgical device for treating biological tissue, wherein the electrosurgical device is An electrosurgical generator arranged to supply microwave energy and / or high-frequency energy, The electrosurgical apparatus comprising an electrosurgical instrument according to any one of claims 1 to 11, which is connected to receive the microwave energy and / or the high-frequency energy from the electrosurgical generator.

13. The electrosurgical apparatus according to claim 12, further comprising a surgical scope device including a flexible insertion cord for inserting the electrosurgical instrument into the body of a patient, wherein the insertion cord has an instrument channel and is sized to fit the electrosurgical instrument into the instrument channel.

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