Electrosurgical instrument
阅读说明:本技术 电外科器械 (Electrosurgical instrument ) 是由 C·P·汉考克 帕特里克·伯恩 P·沙阿 于 2019-06-27 设计创作,主要内容包括:一种电外科器械,具有带有增强的柔韧性的辐射尖端。在第一方面中,这通过使所述辐射尖端中的介电材料成形为有利于所述辐射尖端弯曲来实现。在第二方面中,这通过将所述辐射尖端的介电主体和外护套形成为单独的部分以允许所述部分之间的运动和挠曲来实现。通过提高所述辐射尖端的所述柔韧性,可提高所述电外科器械的可操纵性。(An electrosurgical instrument has a radiating tip with enhanced flexibility. In a first aspect, this is achieved by shaping the dielectric material in the radiating tip to facilitate bending of the radiating tip. In a second aspect, this is achieved by forming the dielectric body and the outer sheath of the radiating tip as separate parts to allow movement and flexing between the parts. By increasing the flexibility of the radiating tip, the maneuverability of the electrosurgical instrument may be increased.)
1. An electrosurgical instrument, the electrosurgical instrument comprising:
a coaxial feed cable for conveying microwave and/or radio frequency energy, the coaxial feed cable having an inner conductor, an outer conductor, and a dielectric material separating the inner conductor from the outer conductor; and
a radiating tip disposed at a distal end of the coaxial feed cable to receive the microwave energy and/or the radio frequency energy, the radiating tip comprising:
an energy delivery structure configured to deliver the microwave energy and/or the radiofrequency energy received from the coaxial feed cable from an outer surface of the radiating tip, wherein the energy delivery structure comprises an elongate conductor electrically connected to the inner conductor and extending beyond the distal end of the coaxial feed cable in a longitudinal direction; and
A dielectric body disposed about the elongated conductor,
wherein the dielectric body includes a cavity therein disposed adjacent the elongate conductor to facilitate deflection of the radiating tip.
2. The electrosurgical instrument of claim 1, wherein the cavity is disposed about the elongated conductor.
3. An electrosurgical instrument according to claim 1 or 2, wherein the cavity comprises a lumen extending longitudinally in the dielectric body.
4. The electrosurgical instrument of claim 3, wherein the dielectric body comprises an inner sleeve surrounding the elongated conductor, and wherein the lumen is spaced from the elongated conductor by a radial thickness of the inner sleeve.
5. An electrosurgical instrument according to claim 3 or 4, wherein the lumen has an annular cross-section.
6. The electrosurgical instrument of claim 3, wherein the lumen forms a longitudinally extending groove disposed at an outer surface of the dielectric body.
7. An electrosurgical instrument according to claim 1 or 2, wherein the cavity is formed by a recess in the dielectric body.
8. The electrosurgical instrument of claim 7, wherein the recess forms a circumferential groove extending around the dielectric body.
9. An electrosurgical instrument according to claim 7 or 8, wherein the dielectric body comprises a corrugated surface, and wherein the depressions are formed by corrugations in the corrugated surface.
10. The electrosurgical instrument of any preceding claim, wherein the radiating tip further comprises an outer sheath disposed about an outer surface of the dielectric body, wherein the outer sheath is spaced from the dielectric body to allow relative movement between the outer sheath and the dielectric body.
11. An electrosurgical instrument, the electrosurgical instrument comprising:
a coaxial feed cable for conveying microwave and/or radio frequency energy, the coaxial feed cable having an inner conductor, an outer conductor, and a dielectric material separating the inner conductor from the outer conductor; and
a radiating tip disposed at a distal end of the coaxial feed cable to receive the microwave energy and/or the radio frequency energy, the radiating tip comprising:
an energy delivery structure configured to deliver the microwave energy and/or the radiofrequency energy received from the coaxial feed cable from an outer surface of the radiating tip, wherein the energy delivery structure comprises an elongate conductor electrically connected to the inner conductor and extending beyond the distal end of the coaxial feed cable in a longitudinal direction; and
A dielectric body disposed about the elongated conductor; and
an outer jacket disposed about an outer surface of the dielectric body, wherein the outer jacket is spaced apart from the dielectric body to allow relative movement between the outer jacket and the dielectric body.
12. The electrosurgical instrument of claim 10 or 11, wherein the dielectric body is formed of a first dielectric material and the outer sheath is formed of a second dielectric material different from the first dielectric material.
13. The electrosurgical instrument of claim 12, wherein the first dielectric material has a higher melting temperature than the second dielectric material.
14. The electrosurgical instrument of claim 13, wherein the first dielectric material is polytetrafluoroethylene and the second dielectric material is fluorinated ethylene propylene.
15. The electrosurgical instrument of any one of claims 10-14, wherein the outer sheath comprises a distal tip arranged to cover a distal end of the dielectric body.
16. The electrosurgical instrument of any one of claims 10 to 15, wherein the outer sheath is configured to form a seal around the outer surface of the dielectric body.
17. The electrosurgical instrument of any one of claims 11 to 16, wherein the dielectric body comprises a helical body through which the elongate conductor extends.
18. An electrosurgical instrument, the electrosurgical instrument comprising:
a coaxial feed cable for conveying microwave and/or radio frequency energy, the coaxial feed cable having an inner conductor, an outer conductor, and a dielectric material separating the inner conductor from the outer conductor; and
a radiating tip disposed at a distal end of the coaxial feed cable to receive the microwave energy and/or the radio frequency energy, the radiating tip comprising:
an energy delivery structure configured to deliver the microwave energy and/or the radiofrequency energy received from the coaxial feed cable from an outer surface of the radiating tip, wherein the energy delivery structure comprises an elongate conductor electrically connected to the inner conductor and extending beyond the distal end of the coaxial feed cable in a longitudinal direction; and
a dielectric body disposed about the elongated conductor;
wherein the dielectric body comprises a helical body through which the elongate conductor extends.
19. An electrosurgical instrument according to any preceding claim, wherein:
the energy delivery structure comprises a proximal tuning element and a distal tuning element, each of the proximal tuning element and the distal tuning element electrically connected to the elongate conductor, the proximal tuning element and the distal tuning element longitudinally spaced apart by a length of the elongate conductor; and is
The dielectric body includes a first dielectric spacer disposed between the proximal tuning element and the distal tuning element.
20. The electrosurgical instrument of any one of claims 1 to 18, wherein:
the energy delivery structure comprises a distal electrode and a proximal electrode disposed on a surface of the dielectric body, the distal and proximal electrodes being physically separated from each other by an intermediate portion of the dielectric body;
the proximal electrode is electrically connected to the outer conductor; and is
The distal electrode is electrically connected to the inner conductor via the elongated conductor.
21. The electrosurgical instrument of claim 20, further comprising a tuning element mounted in the middle portion of the dielectric body.
22. An electrosurgical apparatus for treating biological tissue, the electrosurgical apparatus comprising:
an electrosurgical generator arranged to supply microwave energy and/or radiofrequency energy; and
an electrosurgical instrument according to any preceding claim, connected to receive the microwave energy and/or the radiofrequency energy from the electrosurgical generator.
23. The electrosurgical apparatus of claim 22, further comprising a surgical scoping device comprising a flexible cord having an instrument channel, wherein the electrosurgical instrument is sized to fit within the instrument channel.
Technical Field
The present invention relates to an electrosurgical instrument for delivering microwave energy and/or radiofrequency energy to biological tissue for ablating target tissue. The probe may be inserted through a channel of an endoscope or catheter, or may be used in laparoscopic or open surgery. The device may be used for pulmonary or gastrointestinal applications, but is not limited thereto.
Background
Electromagnetic (EM) energy and in particular microwave and Radio Frequency (RF) energy has been found to be useful in electrosurgery because of its ability to cut, coagulate and ablate body tissue. Generally, an apparatus for delivering EM energy to body tissue includes a generator containing a source of EM energy, and an electrosurgical instrument connected to the generator for delivering energy to the tissue. Conventional electrosurgical instruments are often designed to be inserted percutaneously into a patient's body. However, it may be difficult to position the instrument percutaneously in the body, for example, if the target site is in a moving lung or a thin-walled section of the Gastrointestinal (GI) tract. Other electrosurgical instruments may be delivered to the target site by a surgical scoping device (e.g., an endoscope) that may extend through a channel within the body, such as the airway or the lumen of the esophagus or colon. This allows for minimally invasive treatment, which can reduce patient mortality and reduce intraoperative and postoperative complication rates.
The use of microwave EM energy for tissue ablation is based on the fact that biological tissue is composed primarily of water. Human soft organ tissue typically has between 70% and 80% moisture. Water molecules have a permanent electric dipole moment, which means that there is a charge imbalance across the molecule. This charge imbalance causes the molecules to move in response to the force generated by the application of the time-varying electric field, as the molecules rotate to align their electric dipole moment with the polarity of the applied field. At microwave frequencies, rapid molecular oscillations can lead to frictional heating and consequent dissipation of field energy in the form of heat. This is called dielectric heating.
This principle is used in microwave ablation therapy, where water molecules in the target tissue are rapidly heated by applying a local electromagnetic field at microwave frequencies, resulting in tissue coagulation and cell death. It is known to use microwave emitting probes to treat various diseases in the lungs and other organs. For example, in the lung, microwave radiation may be used to treat asthma and ablate tumors or lesions.
The RF EM energy may be used for cutting and/or coagulating of biological tissue. The method of cutting using RF energy operates on the following principle: when an electric current (assisted by the ionic content of the cells, i.e., sodium and potassium) passes through the tissue matrix, the resistance to electron flow across the tissue generates heat. When a pure sine wave is applied to the tissue matrix, sufficient heat is generated within the cells to evaporate the water of the tissue. Therefore, the internal pressure of the cell, which cannot be controlled by the cell membrane, is sharply increased, thereby causing the cell to rupture. When this occurs over a large area, it is foreseeable that the tissue has already been severed.
RF coagulation operates by: a less efficient waveform is applied to the tissue, whereby instead of evaporation, the cell contents are heated to about 65 ℃. This dries the tissue by the desiccant and also denatures the proteins in the vessel wall and the collagen that makes up the cell wall. Denaturing the protein serves as a stimulus to the coagulation cascade, and thus coagulation is enhanced. At the same time, collagen in the cell wall is denatured from rod-like molecules to coil molecules, which constricts the vessel and reduces the size, giving the clot an anchoring point and a smaller occluded area.
Disclosure of Invention
Most generally, the present invention provides an electrosurgical instrument having a radiating tip with enhanced flexibility. In a first aspect of the invention, this may be achieved by shaping the dielectric material in the radiating tip to facilitate bending of the radiating tip. In a second aspect of the invention, this is achieved by forming the dielectric body and the outer sheath of the radiating tip as separate parts to allow movement and flexing between the parts. By increasing the flexibility of the radiation tip, the maneuverability of the electrosurgical instrument may be increased.
The electrosurgical instrument of the present invention may be used to ablate target tissue in the body. To effectively ablate the target tissue, the radiation tip should be positioned as close to (and in many cases inside) the target tissue as possible. To reach target tissue (e.g., in the lungs), it may be necessary to guide the device through a passageway (e.g., an airway) and around obstacles within the body. Thus, making the radiation tip more flexible can facilitate directing the radiation tip to the target tissue. For example, where the target tissue is in the lung, this may facilitate maneuvering of the instrument along a potentially narrow and tortuous pathway (such as a small bronchus). By positioning the radiation tip as close as possible to the target tissue, irradiation of surrounding healthy tissue can be avoided or reduced.
According to a first aspect of the present invention there is provided an electrosurgical instrument comprising: a coaxial feed cable for conveying microwave and/or radio frequency energy, the coaxial feed cable having an inner conductor, an outer conductor, and a dielectric material separating the inner conductor from the outer conductor; and a radiating tip disposed at a distal end of the coaxial feed cable to receive microwave energy and/or radio frequency energy, the radiating tip comprising: an energy delivery structure configured to deliver microwave energy and/or radiofrequency energy received from the coaxial feed cable from an outer surface of the radiating tip, wherein the energy delivery structure comprises: an elongated conductor electrically connected to the inner conductor and extending beyond the distal end of the coaxial feeder cable in the longitudinal direction; and a dielectric body disposed about the elongate conductor, wherein the dielectric body includes a cavity therein disposed adjacent the elongate conductor to facilitate flexing of the radiating tip.
The energy delivery structure may be configured to deliver only microwave energy, or only radiofrequency energy. Also in embodiments, the energy delivery structure may be configured to be capable of delivering both microwave energy and radiofrequency energy, either separately or simultaneously. The elongated conductor may be configured as an antenna for radiating microwave energy, or as a member that provides an electrical connection with the active electrode to deliver radio frequency energy (e.g., in combination with a return electrode connected to the outer conductor).
Electrosurgical instruments may be suitable for ablating confined or inaccessible locations, particularly in the human body, such as tissue in the lungs or uterus. However, it is understood that the instrument may be used to ablate tissue in other organs.
The coaxial feed cable may be a conventional low loss coaxial cable connectable at one end to an electrosurgical generator. In particular, the inner conductor may be an elongate conductor extending along a longitudinal axis of the coaxial feeder cable. The dielectric material may be disposed 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 disposed on a surface of a dielectric material. The coaxial feeder cable may also include an outer protective jacket for insulating and protecting the cable. In some examples, the protective sheath may be made of or coated with a non-stick material to prevent tissue from adhering to the cable. A radiating tip is located at the distal end of the coaxial feed cable and is used to deliver EM energy transmitted along the coaxial feed cable into the target tissue. The radiating tip may be permanently attached to the coaxial feed cable, or the radiating tip may be removably attached to the coaxial feed cable. For example, a connector may be provided at the distal end of the coaxial feeder cable, the connector being arranged to receive the radiating tip and make the required electrical connection.
The dielectric body may include a channel for conveying the elongated conductor. The instrument may be assembled by feeding an elongated conductor through the channel or by depositing a dielectric body on the elongated conductor.
The dielectric body may be substantially cylindrical, but other shapes are possible. The dielectric body may be attached to a distal end of the coaxial feed cable. In some examples, the dielectric body 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 may simplify the construction of the radiating tip and avoid reflection of EM energy at the boundary between the radiating tip and the coaxial feed cable. In other examples, a second dielectric material spaced apart from the dielectric material of the coaxial feed cable may be used to form the dielectric body. 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 delivering microwave energy into the target tissue. The dielectric body may also include a plurality of different pieces of dielectric material selected and arranged to shape the radiation profile in a desired manner. The dielectric body may be made of or coated with a non-stick material (e.g., PTFE) to prevent tissue adhesion to the dielectric body.
The dielectric body extends in a longitudinal direction, i.e. in a direction parallel to the longitudinal axis of the coaxial feeder cable. An elongated conductor extends within the passage in the dielectric body. The channel may be a passage extending through a portion of the dielectric body. The elongated conductor may 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 body. In some embodiments, the elongate conductor may be a distal portion of the inner conductor that extends beyond the distal end of the coaxial feeder cable. In other words, the inner conductor may extend beyond the distal end of the coaxial feeder cable and into the dielectric body to form an elongated conductor. This may facilitate the formation of a radiating tip at the distal end of the coaxial feeder cable, as it may make it unnecessary to connect a separate conductor to the distal end of the inner conductor.
The radiating tip may be configured to act as a microwave radiator, i.e. the radiating tip may be configured to radiate microwave energy transmitted by the coaxial feed cable. In particular, microwave energy delivered from the coaxial feed cable to the radiating tip may radiate along the length of the elongate conductor. The outer conductor may terminate at the distal end of the coaxial feeder cable such that the elongate conductor extends beyond the distal end of the outer conductor. In this way, the radiating tip may act as a microwave monopole antenna. Thus, microwave energy delivered to the radiating tip may radiate from the elongate conductor into the surrounding target tissue.
Additionally or alternatively, the radiating tip may be configured to cut or ablate the target tissue using RF energy. For example, the radiation tip may include a pair of exposed electrodes (e.g., bipolar RF electrodes) arranged to cut or ablate the target tissue. One of the electrodes may be electrically connected to the inner conductor (e.g., via the elongated conductor), and another of the electrodes may be electrically connected to the outer conductor. In this manner, biological tissue located between or around the electrodes can be cut and/or ablated by delivering radio frequency energy to the proximal and distal electrodes. In some cases, the radiating tip may be configured to deliver both microwave energy and RF energy, either separately or simultaneously. This may allow the functionality of the electrosurgical instrument to be rapidly changed by switching between or varying the application of RF energy and microwave energy.
The cavity may be formed in a portion of the dielectric body disposed around the elongate conductor, i.e., the cavity may be located in a portion of the dielectric body having a channel through which the elongate conductor extends. The cavity may be spaced from the channel in a transverse (e.g., radial) direction that is perpendicular to the longitudinal direction. For example, where the dielectric body is cylindrical, the passage may be substantially centered about a central axis of the cylindrical body, and the cavity may be radially spaced from the passage. The cavity may be a void formed within or on a surface of the dielectric body, e.g., a region where the dielectric material of the dielectric body is not present. For example, the cavity may be a recess or depression on the surface of the dielectric body. The cavity may be formed in an outer surface of the dielectric body. Alternatively, the cavity may be formed in an inner surface of the dielectric body, e.g. in a wall of the channel. Where a cavity is formed within the dielectric body, the cavity may be a void or cavity enclosed within the dielectric body.
The cavity may reduce the amount of material in the portion of the dielectric body surrounding the elongated conductor. For example, the cavity may reduce the overall thickness in the lateral direction of the material forming the dielectric body in the portion of the dielectric body surrounding the elongate conductor. This may reduce the stiffness of the dielectric body surrounding the elongated conductor. The cavity may also act as a bending point or flexure that facilitates bending of the dielectric body. The cavity may thus serve to increase the flexibility of the dielectric body. This may facilitate bending of the radiation tip, which in turn may facilitate guiding of the electrosurgical instrument through a narrow and tortuous pathway in the body. This may enable the radiation tip to be positioned as close to the target tissue as possible to ensure efficient energy delivery to the target tissue. The volume of the cavity may be relatively small compared to the total volume of the dielectric material. In this way, the cavity may increase the flexibility of the dielectric body without significantly affecting the impedance matching properties of the dielectric body. Thus, the radiation profile of the radiation tip may not be significantly affected by the presence of the cavity.
The cavity may be empty (e.g., the cavity may be filled with air). In some cases, the cavity may be filled with a deformable material to increase the flexibility of the dielectric body.
In some cases, a plurality of cavities may be formed in the dielectric body. The cavities may be arranged along the length of the dielectric body, for example, the cavities may be longitudinally spaced apart. This may provide multiple bending points along the length of the dielectric body to facilitate bending of the dielectric body along its length. The cavity may also be disposed about a longitudinal axis of the dielectric body. This may facilitate bending of the dielectric body in different directions relative to the longitudinal direction. Thus, having multiple cavities may further improve the flexibility of the dielectric body. The plurality of cavities may be evenly spaced apart, or the plurality of cavities may be arranged in any manner. The cavity may be disposed on the dielectric body to facilitate bending of the dielectric body in a particular direction. For example, placing the cavity on the side of the dielectric body may facilitate bending of the dielectric body toward the side, e.g., by reducing the stiffness of the dielectric body on the side with the cavity. The plurality of cavities may be arranged about a longitudinal axis of the dielectric body to facilitate bending of the dielectric body in a plurality of directions.
The cavity (or cavities) may be formed during the fabrication of the dielectric body. For example, the dielectric body may be molded to include one or more cavities. Alternatively, the cavity may be formed by drilling a hole in the dielectric body and/or cutting away a portion of the dielectric body.
In some embodiments, the cavity may be formed by a lumen extending longitudinally in the dielectric body. The dielectric body may include an inner sleeve that surrounds the elongated conductor (i.e., provides a passage through which the elongated conductor extends). The lumen may be spaced from the elongated conductor by a radial thickness of the inner sleeve. The lumen may extend along all or a portion of the dielectric body to increase the flexibility of the dielectric body. The internal cavity may be a passage or channel extending through a portion of the dielectric body. The cavity may be a closed cavity, i.e., the cavity may be formed inside the dielectric body. Alternatively, the cavity may be an open cavity, i.e. the cavity may be formed at a surface of the dielectric body. In some examples, the lumen may be parallel to the channel in the dielectric body. In other examples, the lumen may have a helical shape such that the lumen wraps around the channel in the dielectric body. The lumen may have a circular cross-section, or the lumen may have a cross-section of another shape. Advantageously, the lumen may be used to convey wiring or other inputs through the radiation tip. The lumen in the dielectric body and the lumen in the coaxial feed cable may be continuous such that the input end may be conveyed from the proximal end of the electrosurgical instrument to the radiating tip. For example, the lumen may be used to convey a fluid (e.g., a coolant fluid for cooling the tip). The lumen may be used to deliver a control wire (e.g., to control a blade or other mechanism located at the distal end of the radiation tip).
There may be multiple lumens (e.g., where there are multiple cavities) extending longitudinally in the dielectric body. The lumens may be arranged such that the lumens are spaced around the channel in the dielectric body, for example, the lumens may be evenly spaced around the channel. This may facilitate bending of the radiation tip in multiple directions relative to the longitudinal axis.
In some embodiments, the inner cavity can have an annular cross-section that surrounds a portion of the dielectric body in which the channel is formed. In other words, the dielectric body may include: an inner portion having a channel formed therein containing an elongated conductor; and an outer part forming a sleeve around the inner part. The outer portion may be spaced apart from the inner portion to form an inner cavity between the inner and outer portions. The outer portion may be spaced from the inner portion, for example using a spacer. By providing the inner cavity with an annular cross-section surrounding the inner portion of the dielectric body, a cavity can be effectively formed around the longitudinal axis of the dielectric body. This may result in the stiffness of the dielectric body being substantially symmetric about the longitudinal axis, which may facilitate bending of the dielectric body relative to the longitudinal axis, e.g., there may be no preferential bending direction. The lumen may be arranged such that its annular cross-section is substantially centered on the longitudinal axis of the dielectric body such that the lumen is axially symmetric about the longitudinal axis. This may further improve the isotropy of the stiffness of the dielectric body around the longitudinal axis.
In some embodiments, the lumen may be disposed on an outer surface of the dielectric body. For example, the internal cavity may form a longitudinally extending groove on the outer surface of the dielectric body. The cavity may thus be an open cavity on the outer surface of the dielectric body. Where the dielectric body includes a plurality of cavities, a plurality of trenches may be formed on the outer surface. In addition to facilitating bending of the radiation tip, the grooves may also serve as engagement features. For example, the outer protective sheath of the electrosurgical instrument may have one or more protrusions engaged in the groove to secure the outer protective sheath relative to the radiation tip. In another example, the channel can be used to guide the radiation tip along an instrument channel of a surgical scoping device and/or to maintain a desired orientation of the radiation tip. The grooves on the surface of the dielectric body may also be used to hold the radiation tip, e.g. to rotate the radiation tip.
In some implementations, the cavity can be formed by a recess in the dielectric body. The recess may be formed in a surface of the dielectric body. The recess may be a recess or notch formed in a surface of the dielectric body. The depression may serve as a bending point or flexure of the dielectric body, e.g., the depression may constitute a region of less resistance to bending than other regions of the dielectric body (e.g., due to the reduced thickness of the dielectric body at the depression). The length of the recess may be perpendicular to the longitudinal direction to facilitate bending of the dielectric body relative to the longitudinal direction. A plurality of recesses may be formed in the dielectric body to provide a plurality of bending points or flexures. In this manner, bending the dielectric body at multiple points along the length of the dielectric body may be facilitated.
In some implementations, the recess can be formed in an outer surface of the dielectric body. In other embodiments, the recess may be formed in an inner surface of the dielectric body, for example, in a wall of a channel formed in the dielectric body. Where there are multiple depressions, some of the depressions may be formed in the outer surface while some of the depressions may be formed in the inner surface.
In some implementations, the recess can form a trench extending around a circumference of the dielectric body. The trench may be formed in an outer surface of the dielectric body. The trench may form a ring or annulus around the circumference of the dielectric body. In this case, the grooves may be oriented in a direction perpendicular to the longitudinal direction. In other cases, the trench may have a spiral shape such that the trench wraps around the dielectric body along a length of the dielectric body. By forming the trench around the circumference of the dielectric body, the stiffness of the dielectric body may be substantially symmetric about the longitudinal axis. This may facilitate bending of the dielectric body relative to the longitudinal axis.
In some embodiments, the dielectric body may include a corrugated surface, and the depressions may be formed by corrugations in the corrugated surface. The outer surface of the dielectric body may be corrugated, and/or the inner surface (wall of the channel) may be corrugated. In some cases, both the outer surface and the inner surface of the dielectric body may be corrugated. For example, a portion of the dielectric body may be formed from a length of corrugated tubing or pipe. Suitable bellows or tubing may be made of PTFE, FEP or PFA. The corrugated surface may comprise a series of corrugations or ridges arranged to form a series of peaks and valleys. The depressions may correspond to valleys formed between adjacent corrugations/ridges. Since the corrugated surface may include a plurality of corrugations, a plurality of depressions may be formed in the corrugated surface. The depressions may serve as bending points or flexures for the dielectric body, as discussed above. Bellows are widely commercially available. This may facilitate the production of flexible radiation tips at low cost.
In some embodiments, the radiating tip can further include an outer jacket disposed about the outer surface of the dielectric body, the outer jacket being spaced apart from the dielectric body to allow relative movement between the outer jacket and the dielectric body. The outer sheath may serve to protect the radiating tip from the environment and to isolate the radiating tip from the environment. The outer sheath may be made of or coated with a non-stick material (e.g., PTFE) to prevent tissue from adhering to the outer sheath. The outer jacket may be a sleeve of insulating material covering the outer surface of the dielectric body. For example, the outer jacket may be formed from a length of heat shrink tubing shrunk around the dielectric body. The outer sheath is spaced from the dielectric body, which means that the outer sheath is formed separately from the dielectric body, i.e. the outer sheath and the dielectric body are formed as separate components. Further, there may be no adhesive or other connecting member to secure the outer jacket to the dielectric body. The outer jacket may be retained on the dielectric body via friction between the outer jacket and the dielectric body. Thus, a small amount of relative movement between the outer surface of the dielectric body and the outer sheath may be possible. In this way, the outer jacket may move relative to the surface of the dielectric body when the dielectric body is bent to avoid stress buildup in the outer jacket. For example, the outer jacket may "bunch up" around the inside of the bend in the dielectric body. Thus, the outer sheath may not provide any significant resistance to bending of the radiating tip, i.e. the outer sheath may not significantly increase the stiffness of the radiating tip. Forming the outer sheath separately from the dielectric body may thus facilitate bending of the radiating tip. Additionally, this may avoid stress concentrations at the interface between the dielectric body and the outer jacket that may cause cracking of the dielectric body and/or tearing of the outer jacket.
The outer sheath may be attached at one end to the distal end of the coaxial feeder cable to fix the position of the outer sheath relative to the coaxial feeder cable. For example, the outer jacket may be attached to the protective jacket of the coaxial feeder cable. In some cases, the outer jacket may be a continuation of the protective jacket of the coaxial feed cable, e.g., the outer jacket may be a distal portion of the protective jacket of the coaxial feed cable that extends beyond the distal end of the coaxial feed cable. Where a cavity is formed on the outer surface of the dielectric body, an outer jacket may be used to cover the cavity. In this way, the radiation tip may have a smooth outer surface despite the presence of the cavity in the dielectric body.
The configuration of the outer sheath may provide an independent aspect of the invention. According to this aspect, there is provided an electrosurgical instrument comprising: a coaxial feed cable for conveying microwave and/or radio frequency energy, the coaxial feed cable having an inner conductor, an outer conductor, and a dielectric material separating the inner conductor from the outer conductor; and a radiating tip disposed at a distal end of the coaxial feed cable to receive microwave energy and/or radio frequency energy, the radiating tip comprising: an energy delivery structure configured to deliver microwave energy and/or radiofrequency energy received from the coaxial feed cable from an outer surface of the radiating tip, wherein the energy delivery structure comprises: an elongated conductor electrically connected to the inner conductor and extending beyond the distal end of the coaxial feeder cable in the longitudinal direction; and a dielectric body disposed around the elongated conductor; and an outer jacket disposed around an outer surface of the dielectric body, wherein the outer jacket is spaced from the dielectric body to allow relative movement between the outer jacket and the dielectric body.
Features of the first aspect of the invention may be shared with the second aspect of the invention and will not be discussed. In particular, the dielectric body of the electrosurgical instrument of the second aspect of the invention may comprise a cavity (or cavities) as discussed above for the first aspect of the invention.
Embodiments of the first or second aspect of the invention set out above may include the following features.
In some embodiments, the dielectric body can be formed of a first dielectric material and the outer jacket can be formed of a second dielectric material different from the first dielectric material. The first dielectric material and the second dielectric material may be selected to improve impedance matching of the radiating tip to the target tissue. The first dielectric material and the second dielectric material may also be selected to facilitate bending of the radiation tip. For example, the second dielectric material may have a lower stiffness than the first dielectric material. This may ensure that the outer sheath does not significantly increase the overall stiffness of the radiating tip.
In some embodiments, the first dielectric material may have a higher melting temperature than the second dielectric material. This may enable the outer jacket to be formed by melting or shrinking the second dielectric material over the dielectric body. For example, the outer jacket may be formed from a heat shrink material tube made from a second dielectric material. A heat shrink tube may be placed over the dielectric body and then shrunk over the dielectric body by the application of heat. Since the melting temperature of the first dielectric material is higher than the melting temperature of the second dielectric material, the dielectric body does not melt when the outer jacket is formed over the dielectric body. This may ensure that the outer sheath fits well over the dielectric body, while keeping them as separate components to allow relative movement between them. This may facilitate the manufacturing of the radiation tip.
In some embodiments, the first dielectric material may be Polytetrafluoroethylene (PTFE) and the second dielectric material may be Fluorinated Ethylene Propylene (FEP). PTFE has a higher melting temperature than FEP. FEP is generally softer than PTFE and therefore may be able to bend easily. Using this combination of materials, the outer jacket can be formed by melting the FEP over the dielectric body (e.g., using a die) to form the outer jacket directly on the dielectric body. Alternatively, a length of heat shrink tubing made of FEP may be used to form the outer jacket over the dielectric body.
In some embodiments, the outer sheath can include a distal tip disposed to cover the distal end of the dielectric body. Thus, the outer jacket can cover both the outer surface (e.g., side) and the distal end of the dielectric body. In this way, the outer jacket can form a cap on the dielectric body. The distal tip may be made of the same dielectric material (e.g., a second dielectric material) as the rest of the outer sheath. The distal tip may be pointed to facilitate insertion of the radiation tip into the target tissue. Optionally, the distal tip may be rounded or flat. The distal tip may be used to improve impedance matching with the target tissue. The distal tip may also be used to prevent fluid in the environment surrounding the radiation tip from entering the space (e.g., cavity) between the outer sheath and the dielectric body.
In some embodiments, the outer jacket can be configured to form a seal around an outer surface of the dielectric body. The outer jacket may thus encapsulate the outer surface of the dielectric body. The outer sheath may be used to prevent fluid in the environment surrounding the radiating tip from entering the space between the outer sheath and the dielectric body. For example, a seal may be formed between the outer jacket and the dielectric body at the proximal end of the dielectric body and at the distal end of the dielectric body. Where the outer sheath includes a distal tip, sealing may only be required at the proximal end of the dielectric body. In some cases, a seal may be formed between the outer jacket and the distal end of the coaxial feed cable to prevent leakage at the interface between the coaxial feed cable and the radiating tip.
Where the cavity is on an outer surface of the dielectric body, the outer jacket may serve to trap air (or some other fluid) in the cavity, and to prevent fluid in the surrounding environment from entering the cavity.
In some embodiments, the radiating tip may also include a dielectric choke. The dielectric choke may be a piece of electrically insulating material mounted relative to the outer conductor (e.g., between the outer conductor and the proximal electrode) to reduce the propagation of EM energy reflected back down the coaxial feed cable at the radiating tip. This may reduce the amount by which the radiation profile of the radiating tip extends along the coaxial feeder cable and provide an enhanced radiation profile.
The dielectric body may comprise a helical body through which the elongate conductor extends. In other words, a portion of the dielectric body may be formed as a helix, wherein the helix is wound around a length of elongated conductor. The channel through which the elongate conductor extends may thus be formed by the coil of the helix. The helical shape of the dielectric body may facilitate bending of the dielectric body and may provide a substantially symmetric stiffness of the dielectric body about a longitudinal axis of the dielectric body. The helical body may act as a helical spring, providing a high degree of flexibility of the radiation tip. Furthermore, the helical shape of the dielectric body may facilitate the dielectric body returning to its original shape after being bent. For example, after bending to traverse a serpentine path, the radiation tip may straighten back due to the resiliency of the dielectric body.
The spiral dielectric body may constitute a third independent aspect of the invention. According to this aspect, there is provided an electrosurgical instrument comprising: a coaxial feed cable for conveying microwave and/or radio frequency energy, the coaxial feed cable having an inner conductor, an outer conductor, and a dielectric material separating the inner conductor from the outer conductor; and a radiating tip disposed at a distal end of the coaxial feed cable to receive microwave energy and/or radio frequency energy, the radiating tip comprising: an energy delivery structure configured to deliver microwave energy and/or radiofrequency energy received from the coaxial feed cable from an outer surface of the radiating tip, wherein the energy delivery structure comprises: an elongated conductor electrically connected to the inner conductor and extending beyond the distal end of the coaxial feeder cable in the longitudinal direction; and a dielectric body disposed around the elongated conductor; wherein the dielectric body comprises a helical body through which the elongate conductor extends.
Features of the first and second aspects of the invention may be shared with the third aspect of the invention and will not be discussed.
In some embodiments of the electrosurgical instrument of any aspect of the invention discussed above, the energy delivery structure may comprise a proximal tuning element and a distal tuning element, each of the proximal tuning element and the distal tuning element being electrically connected to the elongate conductor, the proximal tuning element and the distal tuning element being longitudinally spaced apart by a length of the elongate conductor. The dielectric body may include a first dielectric spacer disposed between the proximal tuning element and the distal tuning element.
The proximal tuning element may be a piece of electrically conductive material (e.g. metal) located near the proximal end of the radiation tip. The distal tuning element may be a piece of conductive material (e.g., metal) located near the distal end of the radiation tip. Thus, the distal tuning element may be further away from the distal end of the coaxial feed cable than the proximal tuning element. Both the proximal and distal tuning elements are electrically connected to the elongate conductor. For example, the proximal and distal tuning elements may each be disposed on or around the elongate conductor. The proximal and distal tuning elements may be electrically connected to the elongate conductor by any suitable means. For example, the proximal and distal tuning elements may be welded or brazed to the elongate conductor. In another example, the proximal and distal tuning elements may be connected to the elongate conductor using a conductive adhesive (e.g., a conductive epoxy). The proximal and distal tuning elements are spaced apart by a length of the elongate conductor in the longitudinal direction. In other words, a certain section of the elongated conductor is disposed between the proximal and distal electrodes. The proximal and distal tuning elements may be covered by a portion of the dielectric body such that the proximal and distal tuning elements are isolated/protected from the environment.
The proximal and distal tuning elements may be used to shape the profile of the microwave energy emitted by the radiating tip. In particular, the inventors have found that placing longitudinally spaced tuning elements on an elongated conductor can be used to create a radiation profile that is concentrated around the radiating tip. The radiation profile may have an approximately spherical shape. The tuning element may also serve to reduce the tail of the radiation profile that extends back along the coaxial feed cable. In this way, microwave energy delivered to the radiating tip may be emitted from the radiating tip and ablate surrounding target tissue in a well-defined volume around the radiating tip. The shape, size and position of the tuning element may be selected to obtain a desired microwave radiation profile.
The first dielectric spacer may be a portion of the dielectric body located between the proximal tuning element and the distal tuning element. The channel in the dielectric body may be formed partially or completely in the first dielectric spacer. In some cases, the proximal tuning element may be spaced apart from the distal end of the coaxial feed cable. In this case, the dielectric body may comprise a second dielectric spacer disposed between the distal end of the coaxial feed cable and the proximal tuning element.
Where a cavity is formed in the dielectric body, the cavity may be formed in the first dielectric spacer. In some cases, the cavity may be formed in the second dielectric spacer. Optionally, the cavity may be formed in both the first dielectric spacer and the second dielectric spacer. This may further improve the flexibility of the radiation tip.
Where the radiating tip includes an outer sheath, the outer sheath may cover an outer surface of the first dielectric spacer. The outer jacket may be spaced apart from the first dielectric spacer to allow relative movement between the outer jacket and the first dielectric spacer. Where the dielectric body further comprises a second dielectric spacer, the outer jacket may also cover an outer surface of the second dielectric spacer. The outer jacket may also cover the outer surfaces of the proximal and distal tuning elements to protect them from the environment and isolate them from the environment.
In some embodiments of the electrosurgical instrument of any aspect of the invention discussed above, the energy delivery structure may include a distal electrode and a proximal electrode disposed on a surface of the dielectric body, the distal electrode and the proximal electrode being physically separated from each other by a middle portion of the dielectric body. The proximal electrode may be electrically connected to the outer conductor. The distal electrode may be electrically connected to the inner conductor via an elongated conductor.
Since the proximal and distal electrodes are electrically connected to the outer and inner conductors, respectively, the proximal and distal electrodes may receive RF energy transmitted along the coaxial feed cable to function as bipolar RF electrodes. In this manner, biological tissue located between or around the electrodes may be ablated and/or coagulated by transmitting radiofrequency energy to the proximal and distal electrodes. Further, the longitudinal spacing between the proximal and distal electrodes enables the proximal and distal electrodes to function as poles of a dipole antenna when microwave energy is transmitted along the coaxial feed cable. Thus, the radiating tip may act as a microwave dipole antenna when microwave energy is transmitted along the coaxial feed cable. The spacing of the proximal and distal electrodes may depend on the microwave frequency used, as well as the load induced by the target tissue. This configuration of the radiating tip thus allows the use of both RF and microwave energy to treat tissue. The inventors have also found that by switching between RF energy and microwave energy it is possible to change the radiation profile (also referred to as "ablation profile") of the instrument. In other words, the size and shape of the volume of tissue ablated by the electrosurgical instrument can be adjusted by switching between RF energy and microwave energy. This may enable the ablation profile to be changed in situ without having to change the instrument during surgery.
The intermediate portion of the dielectric body may be a dielectric spacer located between the proximal electrode and the distal electrode. The channel in the dielectric body may be partially or completely formed in the middle portion of the dielectric body.
Where a cavity is formed in the dielectric body, the cavity may be formed in a middle portion of the dielectric body. Where the radiating tip includes an outer sheath, the outer sheath may cover an outer surface of the middle portion of the dielectric body. The outer jacket may be spaced apart from the middle portion to allow relative movement between the outer jacket and the dielectric body. The outer sheath may be arranged such that it does not cover the proximal and distal electrodes, i.e. the proximal and distal electrodes are exposed at the surface of the radiation tip. The outer sheath may be arranged such that it is flush with the surfaces of the proximal and distal electrodes such that the radiating tip has a smooth outer surface.
In some embodiments, the radiating tip may further include a tuning element mounted in the middle portion of the dielectric body. The tuning element can be used to shape the radiation profile and improve the impedance match between the radiating tip and the target tissue. The tuning element may comprise a conductive body mounted within the intermediate portion of the dielectric body, the conductive body being electrically connected to the elongate conductor. The tuning element may have dimensions selected to introduce a capacitance to improve the coupling efficiency of the radiating tip. For example, the conductive body may be a sleeve mounted around a portion of the elongate conductor between the proximal and distal electrodes.
The electrosurgical instrument of any aspect of the invention discussed above may form part of a complete electrosurgical system. For example, the electrosurgical system may include: an electrosurgical generator arranged to supply microwave energy and/or radiofrequency energy; and an electrosurgical instrument of the invention connected to receive microwave energy and/or radiofrequency energy from an electrosurgical generator. The electrosurgical apparatus may also include a surgical scoping device (e.g., an endoscope) having a flexible cord for insertion into the body of a patient, wherein the flexible cord has an instrument channel extending along a length thereof, and wherein the electrosurgical instrument is sized to fit within the instrument channel.
In the present specification, "microwave" may be widely used to indicate a frequency range of 400MHz to 100GHz, but is preferably a range of 1GHz to 60 GHz. Preferred point frequencies for microwave EM energy include: 915MHz, 2.45GHz, 3.3GHz, 5.8GHz, 10GHz, 14.5GHz and 24 GHz. 5.8GHz may be preferred. In contrast, the present specification uses "radio frequency" or "RF" to indicate a frequency range that is at least three orders of magnitude lower (e.g., up to 300 MHz). Preferably, the RF energy has a frequency that is high enough to prevent nerve stimulation (e.g., greater than 10kHz) and low enough to prevent tissue whitening or thermal spread (e.g., below 10 MHz). A preferred frequency range for the RF energy may be between 100kHz and 1 MHz.
Herein, the terms "proximal" and "distal" refer to the ends of the electrosurgical instrument that are farther away and closer to the treatment site, respectively. Thus, in use, the proximal end of the electrosurgical instrument is closer to the generator for providing RF and/or microwave energy, while the distal end is closer to the treatment site, i.e. the target tissue within the patient.
The term "conductive" is used herein to mean electrically conductive, unless the context indicates otherwise.
The term "longitudinal" as used herein refers to a direction along the length of the electrosurgical instrument that is parallel to the axis of the coaxial transmission line. The term "transverse" as used herein refers to a direction perpendicular to the longitudinal direction, e.g., radially outward from the longitudinal axis of the coaxial transmission line. The term "inner" means radially closer to the center (e.g., axis) of the instrument. The term "outer" means radially further from the center (axis) of the instrument.
The term "electrosurgery" is used with respect to instruments, devices or tools that are used during surgery and that utilize microwave and/or radio frequency Electromagnetic (EM) energy.
Drawings
Examples of the invention are discussed below with reference to the accompanying drawings, in which:
fig. 1 is a schematic view of an electrosurgical system for tissue ablation as an embodiment of the present invention;
FIG. 2 is a schematic cross-sectional side view of an electrosurgical instrument as an embodiment of the present invention;
FIG. 3 is a schematic cross-sectional side view of an electrosurgical instrument as another embodiment of the present invention;
FIG. 4a is a schematic cross-sectional side view of an electrosurgical instrument as an embodiment of the present invention;
FIG. 4b is a cross-sectional view of a dielectric spacer of the electrosurgical instrument of FIG. 4 a;
FIGS. 5 a-5 c are cross-sectional views of dielectric spacers that may be used in an electrosurgical instrument according to embodiments of the present invention;
FIG. 6 is a schematic cross-sectional side view of an electrosurgical instrument as another embodiment of the present invention;
FIGS. 7a and 7b are perspective views of a dielectric spacer of the electrosurgical instrument of FIG. 6;
FIG. 8 is a diagram illustrating a simulated radiation profile of the electrosurgical instrument of FIG. 2;
FIG. 9 is a diagram illustrating a simulated radiation profile of the electrosurgical instrument of FIG. 6;
FIG. 10 is a schematic cross-sectional side view of an electrosurgical instrument as another embodiment of the present invention; and is
Fig. 11a and 11b show perspective views of dielectric spacers that may be used in an electrosurgical instrument according to embodiments of the present invention.
Detailed Description
Fig. 1 is a schematic view of a
The
The
The
The
The system described above is one way of introducing an instrument into the body of a patient. Other techniques are possible. For example, a catheter may also be used to insert the instrument.
Fig. 2 shows a cross-sectional side view of an electrosurgical instrument 200 as an embodiment of the present invention. The electrosurgical instrument 200 is configured to ablate biological tissue by radiating microwave energy into the tissue. The distal end of the electrosurgical instrument may, for example, correspond to the
A radiating
A
A
Both
The
Microwave energy transmitted along the
The
In summary, the dielectric spacer 228 and the
The ability of the dielectric body to flex may facilitate bending of the
The
Fig. 3 shows a cross-sectional side view of an
A radiating
The
The
A distal portion of the
When the proximal and
Additionally, the radiating
The
Similar to instrument 200, this configuration of
The
The flexibility of the radiating tip of an electrosurgical instrument may also be improved by modifying the shape of the dielectric material in the radiating tip. In particular, one or more cavities may be formed in the dielectric material of the radiating tip to facilitate bending.
Fig. 4a shows a cross-sectional view of an electrosurgical instrument 400 as an embodiment of the present invention. Electrosurgical instrument 400 is similar to electrosurgical instrument 200 described above, except that the dielectric spacer of the electrosurgical instrument includes an annular lumen extending therethrough. Reference numerals corresponding to those used in fig. 2 are used in fig. 4a to indicate features of the electrosurgical instrument 400 corresponding to those described above with respect to fig. 2.
Electrosurgical instrument 400 includes a
The
In addition to the
Fig. 5a shows a cross-sectional view of the
Fig. 5b shows a cross-sectional view of another dielectric spacer 510. The dielectric spacer 510 includes a central passage 512 through which the
Figure 5c shows a cross-sectional view of another
The cavity or lumen need not extend along the entire length of the dielectric spacer. For example, the lumen or cavity may extend along only a portion of the dielectric spacer, or may have one or more radial support arms spanning therethrough. In some cases, multiple lumens or cavities may be provided that extend along different portions of the dielectric spacer. Different types of cavities or lumens may be combined within the dielectric spacer. Where it is desired that the radiating tip be able to preferentially bend in a particular direction, a cavity or lumen may be provided on the corresponding side of the dielectric spacer to reduce the stiffness of the spacer on that side. In some embodiments (not shown), a lumen may be formed in the
Fig. 6 shows a cross-sectional view of an electrosurgical instrument 600 as another embodiment of the present invention. Electrosurgical instrument 600 is similar to electrosurgical instrument 200 described above, except that the dielectric spacers of the electrosurgical instrument include a shape to enhance its flexibility. Reference numerals corresponding to those used in fig. 2 are used in fig. 6 to indicate features of the electrosurgical instrument 600 that correspond to features described above with respect to fig. 2.
Electrosurgical instrument 600 includes a dielectric spacer 602 in its radiating
The
In other embodiments (not shown), a large number of trenches may be provided in the outer surface of the dielectric spacer to provide additional bending points for the dielectric spacer. Trenches may also be formed on the inner surface of the dielectric spacer, e.g., on the walls of the channel 603 through which the
Fig. 8 shows a simulated radiation profile of the electrosurgical instrument 200 in the target tissue. The radiation profile was simulated for a microwave frequency of 5.8GHz using finite element analysis software. The radiation profile indicates the resulting volume of tissue ablated by microwave energy. As can be seen in fig. 8, the radiation profile is concentrated around the radiation tip and defines an approximately spherical area.
Fig. 9 shows a simulated radiation profile of an electrosurgical instrument 600 in a target tissue. The radiation profile was simulated for a microwave frequency of 5.8GHz using finite element analysis software. Similar to the radiation profile shown in fig. 8, the radiation profile of electrosurgical instrument 600 is centered around the radiation tip and defines an approximately spherical area. The shape of the radiation profile of the electrosurgical instrument 600 is not significantly affected by the presence of the first and second trenches 604, 606 in the dielectric spacer 602. Thus, the first and second grooves 604, 606 may increase the flexibility of the radiation tip without significantly affecting the radiation profile of the radiation tip.
Fig. 10 shows a cross-sectional view of an
The
Fig. 11a and 11b show perspective views of a dielectric spacer 800 that may be used in an electrosurgical instrument as an embodiment of the invention. For example, the dielectric spacer 800 may replace the dielectric spacer 228 in the electrosurgical instrument 200. The dielectric spacer 800 has a helical body 802 formed as a coil made of a flexible dielectric material (e.g., PTFE). The helical body 802 defines a passage 804 that extends along an axis of the helical body and through which an elongate conductor (e.g., the
In some embodiments (not shown), only a portion of the dielectric spacer may have a spiral shape. The concept of using helically shaped dielectric material in the radiating tip to facilitate bending of the radiating tip may be incorporated into other electrosurgical instruments. For example,
- 上一篇:一种医用注射器针头装配设备
- 下一篇:用于对身体的组织进行治疗的装置