Electrosurgical cutting instruments

Abstract

Various embodiments provide an electrosurgical ablation instrument comprising a shaft defining a lumen, an energy transmission structure for transmitting electromagnetic (EM) energy through the shaft lumen, and an instrument tip attached to the distal end of the shaft. The instrument tip comprises a stationary portion including a first blade element and a movable portion including a second blade element, the movable portion being movable relative to the stationary portion between a closed position in which the first blade element and the second blade element are positioned alongside one another and an open position in which the second blade element is spaced from the first blade element by a gap for receiving biological tissue. The instrument tip also includes a travel limiting mechanism operable to limit a maximum range of relative motion between the second blade element and the first blade element in the open and / or closed positions. The instrument tip further comprises a first electrode, a second electrode, and a planar dielectric, the first and second electrodes being spaced apart and electrically isolated from one another by the planar dielectric, the first and second electrodes being connected to an energy transfer structure for delivering EM energy from the instrument tip. The instrument further comprises an actuator for controlling the relative motion between the movable and stationary parts.

Description

[Technical Field]

[0001] The present invention relates to an electrosurgical cutting instrument for cutting, coagulating, and ablating biological tissue using electromagnetic (EM) energy. In particular, the present invention relates to an electrosurgical cutting instrument having first and second blade elements movable relative to one another between open and closed positions, and further having a movement-limiting mechanism operable to limit the maximum range of relative movement between the first and second blade elements in the open and / or closed positions. [Background technology]

[0002] Surgical resection is a procedure for removing a portion of an organ from the human or animal body. Organs may contain numerous blood vessels. When tissue is cut (i.e., separated or dissected), small blood vessels may be injured or ruptured. Initial bleeding is followed by a clotting cascade, in which blood is converted into a clot in an attempt to plug the bleeding. During surgery, it is desirable for the patient to lose as little blood as possible, so various devices have been developed to attempt to provide bleeding-free resection. Furthermore, in endoscopic procedures, bleeding and the inability to quickly address bleeding are undesirable because blood flow can obstruct the surgeon's view. It is known to use RF energy, instead of a sharp blade, to cut biological tissue. Cutting methods using RF energy work on the principle that when an electric current (assisted by ionic cellular contents) passes through a tissue matrix, the impedance to electron flow in 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 tissue's water content. This results in a large increase in intracellular pressure that cannot be contained by the cell membrane, leading to cell rupture. When this occurs over a large area, tissue can be seen to be dissected.

[0003] While these procedures work admirably in lean tissue, they are less efficient in adipose tissue, which lacks the ionic components that support the electron passage. This means that the latent heat of vaporization of fat is much greater than that of water, requiring significantly more energy to vaporize the cellular contents. RF coagulation works by applying an inefficient waveform to tissue, which heats it to approximately 65°C instead of vaporizing the cellular contents, desiccating the tissue and denaturing proteins in the blood vessel walls. This denaturation acts as a stimulus for the clotting cascade, thereby promoting clotting. At the same time, the collagen in the walls denatures, changing from rod-shaped to coil-shaped molecules, causing the blood vessel to contract and reduce in size, providing anchor points for the clot and reducing the area to be blocked.

[0004] However, RF coagulation is less effective in the presence of fatty tissue because the electrical effect is reduced. Therefore, it can be very difficult to seal blood vessels that are bleeding fatty. The tissue has a burnt, dark appearance instead of having clean white edges. Summary of the Invention [Means for solving the problem]

[0005] Most generally, the present invention provides an expansion on the concept of an electrosurgical cutting instrument described in GB 2567480. The electrosurgical cutting instrument has an energy delivery structure that uses electromagnetic (EM) energy to facilitate cutting and sealing of biological tissue. In particular, the present invention relates to a combined actuation mechanism and energy delivery mechanism that is compact enough to allow the instrument to be inserted into the instrument channel of a surgical scope device such as an endoscope, gastroscope, or bronchoscope. The device can also be used in laparoscopic or open surgery, i.e., to perform bloodless resection of liver lobes with the abdominal cavity open.

[0006] The electrosurgical cutting instrument has an instrument tip having first and second blade elements movable relative to one another between open and closed positions, and in a further development may include a movement limiting mechanism operable to limit the maximum range of relative movement between the first and second blade elements in the open and / or closed positions. In this way, excessive stress on the jaws of the cutting instrument can be avoided and smooth and predictable jaw movement can be ensured.

[0007] Additionally, the electrosurgical cutting instrument may include a control rod for controlling the relative motion between the first and second blade elements, and a development may include a set of overlapping tubes secured to the instrument tip that provide a channel through which the control rod can slide. In this way, movement of the control rod can be smooth and predictable.

[0008] According to a first aspect of the present invention, there is provided an instrument comprising a shaft defining a lumen, an energy transmission structure for transmitting electromagnetic (EM) energy through the lumen of the shaft, an instrument tip attached to a distal end of the shaft, the instrument tip comprising a stationary portion including a first blade element and a movable portion including a second blade element, the movable portion being movable relative to the stationary portion between a closed position in which the first blade element and the second blade element are positioned alongside one another and an open position in which the second blade element is spaced from the first blade element by a gap to receive biological tissue, and / or An electrosurgical cutting instrument is provided that includes: a travel-limiting mechanism operable to limit the maximum range of relative motion between the second blade element and the first blade element in a closed position; an instrument tip including a first electrode, a second electrode, and a planar dielectric, the first and second electrodes being spaced apart and electrically isolated from one another by the planar dielectric, the first and second electrodes being connected to an energy transmission structure for delivery of EM energy from the instrument tip; and an actuator for controlling the relative motion between the movable and stationary parts. The actuator may be a separate element from the instrument tip but connected to the instrument tip for opening and closing the blade elements.

[0009] Optionally, one of the first blade element and the second blade element comprises a longitudinally extending planar dielectric having a first electrode on a first lateral surface thereof, and in the closed position the other of the first blade element and the second blade element is located adjacent to a second lateral surface of the longitudinally extending planar dielectric opposite the first lateral surface thereof.

[0010] Optionally, the second blade element has a length corresponding to the length of the first blade element.

[0011] Optionally, the energy transfer structure includes a coaxial transmission line extending longitudinally through the lumen, the coaxial transmission line comprising an inner conductor separated from an outer conductor by a dielectric material, the inner conductor connected to one of the first and second electrodes and the outer conductor connected to the other of the first and second electrodes for delivering EM energy from the device tip.

[0012] Optionally, the energy transfer structure is for transmitting radio frequency (RF) electromagnetic (EM) energy and microwave EM energy, and the first and second electrodes are operable as active and return electrodes for delivering RF energy transferred from the energy transfer structure, and as a microwave field emission structure for delivering microwave energy transferred from the energy transfer structure. The electrosurgical cutting instrument may provide multiple modes of operation to facilitate cutting and sealing of biological tissue using radio frequency (RF) electromagnetic energy and / or microwave EM energy. In one embodiment, the electrosurgical cutting instrument may include a pair of blade elements providing a scissor-like mechanism capable of providing three complementary modes: (i) gliding RF-based cutting with the blade elements closed; (ii) scissor cutting using a combination of RF energy and applied pressure on tissue grasped between the blade elements; and (iii) coagulation or vessel sealing using a combination of microwave energy and applied pressure on tissue grasped between the blade elements. Furthermore, RF and / or microwave energy can be delivered in either of these modes at a power level sufficient to cause tissue ablation. By appropriately positioning a pair of electrodes on the blade elements, the RF or microwave energy delivered in each operating mode can be focused to the desired area. A pair of electrodes may both be on the same blade element, or there may be an electrode on each blade element. However, it should be understood that in some embodiments, only RFEM energy or only microwave EM energy may be delivered.

[0013] In this configuration, the first and second blade elements may resemble a scissors-type closure mechanism. Accordingly, the second blade element may be arranged to move in shear with the first blade element during movement between the open and closed positions, resulting in mechanical cutting, for example, by application of a shear force. The movable portion may be movable relative to the stationary portion in a plane parallel to the plane defined by the planar dielectric. As used herein, the term "stationary" may mean fixed relative to the distal end of the shaft during use (i.e., when the second blade element is moved between the open and closed positions).

[0014] The shaft may be flexible, suitable for bending or other steering, for example, to reach a treatment site. A flexible shaft may allow the device to be used with a surgical scope device, such as an endoscope. In other examples, the shaft may be rigid, for example, for use in open surgery or laparoscopy.

[0015] The first electrode and the second electrode may be disposed at the cutting interface. In one embodiment, both electrodes are on the same blade element, which may be on either the moving or stationary portion. For example, the second electrode may be disposed on a second lateral surface of a longitudinally extending planar dielectric. This may help provide uniform energy delivery at the cutting interface. When both electrodes are on one blade element, the other blade element may be electrically inactive and may be made of, for example, plastic or other insulator.

[0016] In another example, a first electrode may be on one blade element and a second electrode may be on the other blade element. For example, a longitudinally extending planar dielectric may be on the first blade element and a second electrode may extend along the side of the second blade element.

[0017] Thus, the first and second electrodes may be positioned along either side of the cutting interface with a planar dielectric between them. In this configuration, when RFEM energy is applied to the electrodes, the RFEM energy flows preferentially across the cutting interface between the first and second blade elements. Similarly, when microwave EM energy is applied with the blade elements open, the microwave field emitted from the electrodes has a much higher field strength in the gap between the blade elements than elsewhere.

[0018] In the closed position, the second electrode is separated from the first electrode along the majority of its length by a planar dielectric. When RFEM energy is applied in this position, it flows preferentially to the distal tips and side edges of the closed blade elements, facilitating RF-only gliding cutting by sliding the instrument tip through tissue.

[0019] The movable portion, and thus the second blade element, may be formed from an insulator-coated conductive material that is further coated with Parylene N. For example, the movable portion may be a casting of stainless steel with a ceramic (e.g., alumina spray), synthetic resin (e.g., Bakelite), diamond-like carbon (DLC), enamel coating, or silicone-based paint coating. The second electrode may be formed on a side portion of the second blade element from which the insulator coating and Parylene N coating have been removed. The second electrode may be the exposed conductive material of the movable portion, or may comprise an additional conductive layer (e.g., gold) deposited or otherwise applied to the exposed conductive material.

[0020] The second blade element may include a laterally protruding flange along a side portion thereof, i.e., the flange protrudes toward the first blade element when in the closed position, and the second electrode may be formed on a laterally facing edge of the laterally protruding flange.

[0021] The travel limiting mechanism may be a feature of the instrument tip. Accordingly, structural features of the instrument tip can cooperate to define the relative positions of the first and second blade elements in the open and / or closed positions. This results in uniform open and / or closed positions that do not change between applications. This may differ from conventional techniques in which an actuator or control rod defines these relative positions by having a limited amount of travel. That is, conventionally, the distance a control rod can slide within a shaft may be limited, for example, by a handpiece at the proximal end of the shaft. Such a mechanism may result in variable open and / or closed positions given the flexing of various elements within the shaft, which may be undesirable for certain precision tasks performed with the instrument tip. The travel limiting mechanism may be formed by one or more pairs of cooperating structures formed on the stationary and movable portions. That is, in each pair, one cooperating structure is formed on the stationary portion and the other cooperating structure is formed on the movable portion. One pair of cooperating structures may function to limit the maximum range of relative movement between the second blade element and the first blade element in the open position, while another pair of cooperating structures may function to limit the maximum range of relative movement between the second blade element and the first blade element in the closed position. The travel limiting mechanism may limit the maximum angle between the first blade element and the second blade element in the open position to about 60 degrees.

[0022] The first pair of cooperating structures may include a raised protrusion and a cooperating stop surface (which may be substantially flush with the surrounding surface), which are configured or arranged to abut each other in the open position during use. That is, moving the movable part to the open position causes the raised protrusion to move into contact with the stop surface, preventing further opening of the first and second blade elements. That is, the second blade element is prevented from moving further past the first blade element. The stop surface and / or raised protrusion may be specially formed structures sized and / or shaped to limit the distance the first and second blade elements can move. In embodiments, the movable part includes the raised protrusion and the stationary part includes the stop surface. Specifically, the raised protrusion may be formed on an upper surface of the movable part, distal to a connection (e.g., a pivotal connection) between the movable part and the stationary part. Alternatively, the stop surface may be formed on an upper surface of the stationary part, proximal to the connection between the movable part and the stationary part. The stop surface may be provided by a slot formed in the stationary part by a support arm to which the movable part is attached.

[0023] The second pair of cooperating structures may include a pair of abutment surfaces configured to abut each other in a parallel arrangement in the closed position during use. That is, when the movable portion is moved to the closed position, the two abutment surfaces contact each other and move together substantially parallel to each other. Contact along a surface rather than a point can provide a strong and reliable closure mechanism for the instrument, which may be advantageous, for example, when the first and second blade elements are used to cut tissue. In embodiments, the first abutment surface is formed on an upper surface of the movable portion proximal to a connection (e.g., a pivotal connection) between the movable portion and the stationary portion. The first abutment surface may be formed as an upper surface of a mounting plate of the movable portion, the mounting plate being a proximal extension of the movable portion that extends proximal to the connection to the stationary portion. The mounting plate may be sized and / or shaped to limit the distance the second blade element can move past the first blade element in the closing direction (i.e., the direction of movement from the open position to the closed position). Additionally, a second abutment surface may be formed on the underside of the stationary portion proximal to the connection between the movable portion and the stationary portion. The second abutment surface may be formed as the underside of a support arm of the stationary portion. The support arm may be a lateral and forward (i.e., distally extending) extension of the stationary portion that defines a slot for accommodating movement of the movable portion relative to the stationary portion. The movable portion may be connected (e.g., pivotally connected) to the stationary portion by the support arm. The support arm may be sized and / or shaped to limit the distance that the second blade element can move past the first blade element in the closing direction (i.e., the direction of movement from the open position to the closed position).

[0024] As described above, the stationary portion may include a support arm to which the movable portion is attached, and the support arm may define a slot in the stationary portion for receiving a portion of the movable portion. The length of the slot (i.e., the dimension along the shaft length) may be between 1 mm and 3 mm (preferably less than about 2 mm). The width of the slot (i.e., the dimension along the pivot axis) may be between 0.2 mm and 1.2 mm (preferably greater than about 0.7 mm). The depth of the slot may be between 0.2 mm and 1.2 mm (preferably greater than about 0.6 mm). The slot may be necessary to provide space for a portion of the movable portion (e.g., a proximal portion) to move relative to the stationary portion between the open and closed positions. The support arm may form part of the electrical connection between the energy transfer structure and the second electrode. For example, the stationary portion (e.g., the support arm) may be formed from an insulator-coated conductive material further coated with Parylene N, and may include a proximal contact portion from which the insulator coating and Parylene N coating are removed and electrically connected to the inner or outer conductor of a coaxial transmission line. An advantage of limiting the slot dimensions is that it can ensure a higher quality coating (e.g., of dielectric and / or Parylene N). For example, it is easier to ensure the integrity and uniformity of the coating. The stationary portion (e.g., the support arm) may have a proximal recess for attachment to the distal end of the coaxial transmission line. Other types of electrical connections may also be used. For example, a flexible conductor may be connected between the energy transfer structure (e.g., the inner or outer conductor of the coaxial transmission line) and the first electrode or the second electrode. Preferably, the length of any flexible conductor is no more than one-eighth of the wavelength of the microwave energy to prevent it from affecting the emitted field.

[0025] The coaxial transmission line can be adapted to transmit either or both RFEM energy and microwave EM energy. Alternatively, the energy transmission structure may include different paths for RFEM energy and microwave EM energy. For example, microwave EM energy can be transmitted by a coaxial transmission line, while RFEM energy can be transmitted via a twisted pair, or the like. When separate energy transmission paths are provided, the first and second electrodes may include separate RF and microwave electrode portions to allow RF and microwave energy to be transmitted from different regions of the instrument tip. For example, microwave energy can be transmitted from one of the blade elements, while RF energy can be transmitted between the blade elements. In another embodiment, the electrosurgical instrument is dedicated to transmitting only one of RFEM energy and microwave EM energy.

[0026] The movable part may be attached to the support arm via a pivot connection. For example, the support arm may provide a clevis-type structure that supports a pivot axle to which the movable part is attached. An electrical connection between the energy transfer structure and the second electrode may pass through the pivot connection. For example, the pivot axle may be formed from a conductive material, and the insulator coating (and Parylene N coating) may be removed from the portions of the movable part and the support arm where they contact the pivot axle.

[0027] The dielectric material and inner conductor of the coaxial transmission line may extend beyond the distal end of the outer conductor, and the inner conductor may include an exposed distal portion that is electrically connected to the first electrode, for example, by directly overlapping and contacting the proximal portion of the first electrode.

[0028] Movement between the movable and stationary portions may be rotational or translational, or a combination of the two. In one example, the movable portion is pivotable relative to the stationary portion, such that the second blade element may be angled relative to the first blade element in the open position. This example may be similar to a conventional scissor-type closure mechanism. The second blade element may be movable only through acute angles (i.e., not obtuse angles) between the open and closed positions. In embodiments, the movement limiting mechanism may be configured to limit this acute angle to between 90 degrees and 40 degrees, preferably between 80 degrees and 50 degrees, and more preferably to about 60 degrees. Additionally or alternatively, the movement limiting mechanism may be configured to limit the maximum distance between the jaws in the open position to about 3.5 mm.

[0029] The actuator may include a control rod slidably mounted on a flexible shaft. The control rod may have an attachment mechanism that engages the movable portion, such that longitudinal movement of the control rod within the shaft causes movement of the movable portion relative to the stationary portion. The attachment mechanism may be a hook or any suitable engagement mechanism for transmitting pushing and pulling forces to the movable portion. The movable portion may include an opening (e.g., a circular hole), and the attachment mechanism (e.g., a hook) may be configured to fit within the hole to drive movement of the second blade element past the first blade element. The diameter of the circular hole may be only slightly larger than the diameter of the control rod, thereby preventing the attachment mechanism (e.g., a hook) from moving longitudinally within the hole. This may ensure smooth and predictable jaw movement, since most or all of the longitudinal sliding movement of the control rod is translated into jaw movement.

[0030] The stationary portion may include a support arm that provides a mounting base (e.g., a pivot base) for the movable portion. The planar dielectric may be a separate piece of material attached (e.g., glued or otherwise affixed) to the support arm. The planar dielectric may be formed from a ceramic (e.g., alumina). As used herein, reference to a "planar" material may mean a flat piece of material having a thickness that is substantially less than its width and length. A planar dielectric may have a length dimension parallel to the longitudinal direction, a thickness dimension parallel to the lateral direction, and a width dimension orthogonal to both the length and thickness dimensions. The plane of a planar dielectric refers to the plane in which the length and width dimensions lie, i.e., the plane orthogonal to the width dimension.

[0031] The first electrode may be a conductive material (e.g., gold) deposited or otherwise attached to a first lateral surface of the planar dielectric, a second lateral surface of the planar dielectric facing in an opposite direction to the first lateral surface may be exposed at the cut interface.

[0032] The instrument tip may include a shield attached around the stationary portion. The shield may include an insulating sheath attached around the stationary portion. For example, the insulating shield may cover the support arm of the stationary portion. The insulating shield may also be used to partially cover the first electrode, for example, to ensure that the exposed portion of the first electrode has a desired shape for controlling the delivery of RF or microwave energy. The insulating sheath may have one or more electric field shielding conductive regions, e.g., metalized patches, on its outer surface. These conductive regions may provide electric field shielding, for example, to prevent energy leakage from the instrument in unwanted locations. The shield may be molded to cover the instrument tip after assembly. Alternatively, the shield may be formed from a tube of insulating material that can be cut (e.g., laser cut) to the desired shape and then attached over the blade element. The shield may be formed from a suitable insulating plastic, such as PEEK. The shield material may preferably be able to withstand high temperatures.

[0033] The first blade element may be shaped as a longitudinally extending finger having an upstanding tooth at its distal-most end. The second blade element may be shaped correspondingly, for example, as an elongated finger having a depending tooth at its distal-most end. The distal-most tooth may help to hold tissue in the gap between the jaws when the jaws are closed. Additionally, the second blade element may be shaped to include a second depending tooth at a midpoint between the distal-most end and the proximal-most end. For example, the second depending tooth may be located at or near the midpoint along the second blade element between the distal-most end and the proximal-most end. The upstanding tooth and the two depending teeth may interdigitate to provide improved tissue retention in the gap between the jaws when the jaws are closed.

[0034] A longitudinally extending insert may be attached to the lumen of the flexible shaft to prevent relative motion between the actuator or coaxial cable and the shaft from causing wasted or jerky movement of the instrument tip. The insert may include a tubular body having a plurality of longitudinal sub-lumens formed therein, each of the plurality of longitudinal sub-lumens cutting through the outer surface of the tubular body. The tubular body is sized to fit snugly within the lumen such that the cut circumferential surface of the tubular body defines a plurality of feet that abut the inner surface of the shaft and resist relative motion therebetween.

[0035] The coaxial transmission line may comprise a coaxial cable attached to a first secondary lumen of the tubular body. The actuator may comprise a control rod slidably attached within a second secondary lumen of the tubular body. The control rod may have a low-friction coating (e.g., PTFE, etc.) to facilitate longitudinal sliding relative to the insert. Alternatively, the second secondary lumen may have a low-friction tube (also known as the first tube) attached therein, and the control rod may be slidably attached within the low-friction tube.

[0036] The electrosurgical cutting instrument may include a pair of overlapping tubes that together provide a channel through which a control rod can slide to open and close the jaws. The pair of overlapping tubes may be joined to the instrument tip (e.g., a stationary portion) so that the control rod can slide within the channel in a predictable and reliable manner. For example, movement of the channel relative to the instrument tip is prevented, as this would normally impede smooth movement (e.g., sliding) of the control rod and, associated therewith, smooth opening and closing of the jaws. Specifically, a first tube (also known as a guidewire tube), a second tube (also known as a distal guidewire tube), and a third tube (also known as a proximal short tube) may be provided. The first tube surrounds most of the control rod except for its distal end region. The first tube can surround most or all of the control rod except for its distal end region. That is, the first tube may extend all the way to, and possibly into, a handpiece for manually controlling the opening and closing of the jaws. The distal end region of the control rod may be the last 4 mm to 8 mm (e.g., 5 mm). The first tube may be formed from PTFE or the like. The second tube surrounds the distal end region of the control rod, excluding the control rod's attachment mechanism, and the second tube protrudes proximally from the first tube to define an overlap region where the first tube overlaps the second tube. The attachment mechanism may correspond to the distal-most 2 mm or less of the control rod. The length of the overlap region may be approximately half the length of the second tube, e.g., the overlap region may be approximately 4 mm to 6 mm long, and the second tube may be approximately 8 mm to 12 mm long. The second tube may be formed from PTFE or the like. The third tube surrounds the overlap region and the proximal end region of the stationary portion. The length of the overlap region may be approximately half the length of the third tube, e.g., the overlap region may be approximately 4 mm to 6 mm long, and the third tube may be approximately 8 mm to 12 mm long. The third tube can be formed from polyether block amide (also known as PEBA, PEBAX, or thermoplastic elastomer). The first, second, and third tubes can be bonded to each other and to the stationary part. Bonding can be achieved with an adhesive or pressure-sensitive adhesive and / or by an interference fit between the overlapping tubes.For example, the first tube, the second tube, and the third tube may be substantially clear (i.e., transparent) and may be bonded to the instrument tip (e.g., stationary portion) by ultraviolet adhesive.

[0037] The instrument tip may be sized to fit within the instrument channel of a surgical scope device. Accordingly, a second aspect of the present invention provides an electrosurgical apparatus comprising: an electrosurgical generator for supplying EM energy; a surgical scope device having an instrument cord for insertion into a patient's body, the instrument cord having an instrument channel extending therethrough; and an electrosurgical cutting instrument of the first aspect inserted through the instrument channel of the surgical scope device.

[0038] Optionally, the electrosurgical generator is capable of providing radio frequency (RF) EM energy and microwave EM energy.

[0039] According to a third aspect of the present invention, there is provided an instrument comprising a shaft defining a lumen, an energy transmission structure for transmitting electromagnetic (EM) energy through the lumen of the shaft, an instrument tip attached to a distal end of the shaft, the instrument tip comprising a stationary portion including a first blade element and a movable portion including a second blade element, the movable portion being movable relative to the stationary portion between a closed position in which the first blade element and the second blade element are positioned alongside each other and an open position in which the second blade element is spaced from the first blade element by a gap for receiving biological tissue, a first electrode, a second electrode and a planar dielectric, the first electrode and the second electrode being spaced from each other and electrically insulated by the planar dielectric, the first electrode and the second electrode being connected to the energy transmission structure for delivering EM energy from the instrument tip. an actuator for controlling relative motion between a movable portion and a stationary portion, the actuator including a control rod slidably mounted on a shaft, the control rod having an attachment mechanism that engages the movable portion, whereby longitudinal movement of the control rod within the shaft causes movement of the movable portion relative to the stationary portion; and a first tube, a second tube, and a third tube, the first tube surrounding the control rod except for a distal end region of the control rod, the second tube surrounding the distal end region of the control rod except for the control rod's attachment mechanism, the second tube projecting proximally to the first tube to define an overlap region where the first tube overlaps the second tube, and the third tube surrounding the overlap region and the proximal end region of the stationary portion.

[0040] The third aspect is similar to the first aspect, except that (i) in the third aspect, the travel limiting mechanism is optional, and (ii) in the third aspect, the first tube, the second tube, and the third tube are required. Further features and advantages of the first aspect are equally applicable and translated hereby with respect to the second aspect.

[0041] As used herein, the term "surgical scope device" may refer to any surgical device that includes an insertion tube, which is a rigid or flexible (e.g., steerable) conduit that is introduced into a patient's body during an invasive procedure. The insertion tube may include an instrument channel and an optical channel (e.g., for transmitting light to illuminate the treatment site at the distal end of the insertion tube and / or capture images of the treatment site). The instrument channel may have a diameter suitable for receiving an invasive surgical instrument. The diameter of the instrument channel may be 5 mm or less.

[0042] As used herein, the term "inner" means radially closer to the center (e.g., axis) of the equipment channel and / or coaxial cable. The term "outer" means radially farther from the center (axis) of the equipment channel and / or coaxial cable.

[0043] As used herein, the term "conductive" means electrically conductive, unless the context dictates otherwise.

[0044] As used herein, the terms "proximal" and "distal" refer to the ends of an elongate probe. In use, the proximal end is closer to the generator that provides the RF and / or microwave energy, while the distal end is further from the generator.

[0045] As used herein, "microwave" may be used broadly to denote a frequency range of 400 MHz to 100 GHz, with the range of 1 GHz to 60 GHz being preferred. Specific frequencies considered are 915 MHz, 2.45 GHz, 3.3 GHz, 5.8 GHz, 10 GHz, 14.5 GHz, and 24 GHz. In contrast, this specification uses "radio frequency" or "RF" to denote a frequency range at least three orders of magnitude lower, e.g., up to 300 MHz, preferably 10 kHz to 1 MHz, and most preferably 400 kHz.

[0046] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings. [Brief explanation of the drawings]

[0047] [Figure 1] 1 is a schematic diagram of an electrosurgical system according to an embodiment of the present invention; [Figure 2A] 1 is a perspective view of an instrument tip of an electrosurgical ablation instrument according to an embodiment of the present invention in a closed configuration. [Figure 2B] FIG. 2B is a side view of the instrument tip of FIG. 2A in a closed configuration. [Figure 2C] FIG. 2B is a side view of the instrument tip of FIG. 2A in an open configuration. [Figure 2D] FIG. 2B is a perspective view of the instrument tip of FIG. 2A in an open configuration. [Figure 3A] FIG. 2B is a side view of the instrument tip of FIG. 2A, but with the outer sleeve removed to reveal the internal components. [Figure 3B] FIG. 2B is a perspective view of the instrument tip of FIG. 2A, but with the outer sleeve removed to reveal the internal components. [Figure 4] 1 is a schematic, partially cut-away side view of an electrosurgical ablation instrument according to an embodiment of the present invention; [Figure 5] FIG. 2D is a reproduction, but includes labels corresponding to FIG. 4, to show how the schematic diagram of FIG. 4 translates to the instrument tip of FIG. 2A. [Figure 6A] 1 is a perspective view of the contents of an instrument shaft that can be used in an electrosurgical ablation instrument according to an embodiment of the present invention; FIG. [Figure 6B] FIG. 6B is a cross-sectional view of the instrument shaft shown in FIG. 6A. DETAILED DESCRIPTION OF THE INVENTION

[0048] FIG. 1 is a schematic diagram of a complete electrosurgical system 100 according to an embodiment of the present invention. The system is configured to treat (e.g., cut or seal) biological tissue using electromagnetic (EM) energy (e.g., radio frequency (RF) and / or microwave EM energy) from an instrument tip. The system 100 includes a generator 102 for controllably supplying EM energy (e.g., RF and / or microwave EM energy). A suitable generator for this purpose is described in WO 2012 / 076844, which is incorporated herein by reference. The generator 102 is connected to a handpiece 106 by an interface cable 104. The handpiece 106 may also be connected to receive a fluid supply 107 from a fluid delivery device 108, such as a syringe, although this is not required. Optionally, the handpiece 106 may house an instrument actuation mechanism, such as a thumb-operated slider or plunger, operable by an actuator 109. For example, the instrument actuation mechanism may be used to operate a pivotable blade element of an ablation instrument, as discussed herein. Other mechanisms may also be included in the handpiece. For example, a needle movement mechanism (operable by a suitable trigger on the handpiece) may be provided for positioning a needle with the instrument. The function of the handpiece 106 is to integrate inputs from the generator 102, fluid delivery device 108 and instrument actuation mechanism, along with other inputs that may be required, into a single flexible shaft 112 extending from the distal end of the handpiece 106. The handpiece 106 may be similar to that described in GB 2567480.

[0049] The flexible shaft 112 is insertable through the entire length of the instrument (working) channel of the surgical scope device 114. The flexible shaft 112 has an instrument tip 118 shaped to pass through the instrument channel of the surgical scope device 114 and protrude (e.g., into a patient's body) at the distal end of the insertion tube of the endoscope. The instrument tip 118 includes a pair of blade elements for grasping biological tissue and an energy delivery structure arranged to deliver EM energy (e.g., RF and / or microwave EM energy) transmitted from the generator 102. Optionally, the instrument tip 118 may also include a retractable hypodermic needle for delivering fluid delivered from the fluid delivery device 108. The handpiece 106 includes an actuation mechanism for opening and closing the blade elements of the instrument tip 118. The handpiece 106 may also include a rotation mechanism for rotating the instrument tip 118 relative to the instrument channel of the surgical scope device 114.

[0050] The structure of the instrument tip 118 can be configured to have a maximum outer diameter suitable for passing through the working channel. Typically, the diameter of the working channel of a surgical scope device, such as an endoscope, is less than 4.0 mm, e.g., 2.8 mm, 3.2 mm, 3.7 mm, or 3.8 mm. The flexible shaft 112 can have a smaller maximum diameter, e.g., 2.65 mm. The length of the flexible shaft 112 can be 1.2 m or more, e.g., 2 m or more. In other embodiments, the instrument tip 118 can be attached to the distal end of the flexible shaft 112 after the shaft is inserted through the working channel (and before the instrument cord is introduced into the patient). Alternatively, the flexible shaft 112 can be inserted distally into the working channel before making its proximal connection. In these arrangements, the distal tip assembly 118 can be allowed to have dimensions larger than the working channel of the surgical scope device 114. The above system is one method of introducing an instrument into a patient. Other techniques are possible. For example, the device may be inserted using a catheter.

[0051] Although the examples herein are presented in the context of a surgical scope device, it should be understood that the electrosurgical ablation instrument may be an embodiment of a device suitable for open surgery or for laparoscopic use.

[0052] 2A-2D show different views of an instrument tip 200 of an electrosurgical ablation instrument according to an embodiment of the present invention. FIG. 2A is an isometric view of the instrument tip 200 in a closed position, FIG. 2B is a side view of the instrument tip 200 in a closed position, FIG. 2C is a side view of the instrument tip 200 in an open position, and FIG. 2D is another side view of the instrument tip 200 in the open position. The instrument tip 200 is attached to the distal end of a flexible shaft 204, which may correspond to the flexible shaft 112 described above. In this embodiment, the instrument tip 200 comprises a stationary portion 202 carrying a first electrode 206 (see, e.g., FIG. 2D) and a movable portion 212 carrying a second electrode 214 (see, e.g., FIG. 2D). However, the present invention need not be limited to this configuration. In other embodiments, both electrodes may be provided on either the stationary portion 202 or the movable portion 212.

[0053] The stationary portion 202 has a proximal region that is fixed to the distal end of the flexible shaft 204. The stationary portion 202 extends longitudinally away from the distal end of the flexible shaft 204. At its distal end, the stationary portion 202 defines a first blade element 205, which is a longitudinally extending finger having an upstanding tooth 210 at its distal-most end. The first electrode 206 extends along the outer surface of the first blade element 205. However, in another embodiment, the first electrode 206 may instead extend only along the top surface of the first blade element 205.

[0054] Movable portion 212 is pivotally mounted to stationary portion 202. In this embodiment, movable portion 212 includes second blade element 207 (see, e.g., FIG. 2D ), which is an elongated finger having a length corresponding to first blade element 205. Second blade element 207 has first depending teeth 216 at its distal-most end. Additionally, second blade element 207 has second depending teeth 217 approximately midway along second blade element 207.

[0055] The movable section is pivotable about a pivot axis 219 (see FIGS. 2B and 2C) located at the proximal end of the first blade element 205, thereby allowing the second blade element 207 to swing between an open position (see FIGS. 2C and 2D) in which it is angled away from the first blade element 205, and a closed position (see FIGS. 2A and 2B) in which it is positioned alongside (i.e., laterally adjacent to) the first blade element 205. The movable section's range of motion can be such that the second blade element 207 can adopt an acute angle, e.g., about 60 degrees, with respect to the first blade element 205. This is particularly useful for preventing the jaws from spreading too far, thereby ensuring that the opening and closing mechanism remains smooth and consistent throughout the jaws' range of motion.

[0056] Thus, first blade element 205 and second blade element 207 may feature a scissors-type closure mechanism in which tissue located in the gap between blade elements 205, 207 when in the open position may receive pressure applied thereto as second blade element 207 is moved to the closed position. The upstanding teeth 210 of first blade element 205 and the depending teeth 216, 217 of second blade element 207 act to retain tissue within the gap as second blade element 207 is moved to the closed position.

[0057] The first blade element 205 includes a planar dielectric 208 made, for example, from a ceramic or other suitable electrically insulating material. The planar dielectric 208 defines a plane parallel to the plane about which the second blade element 207 pivots. The planar dielectric 208 provides an insulating barrier between the first electrode 206 and the second blade element 207. For example, the second blade element 207 is positioned to be offset from a first surface of the planar dielectric 208, and the first electrode 206 is formed on a second surface of the planar dielectric 208, the second surface being opposite the first surface of the planar dielectric 208. The first electrode 206 may be made from a highly conductive conductor, such as gold.

[0058] The second electrode 214 extends along the side of the second blade element 207 that slides against the adjacent side of the first blade element 205 (i.e., the first surface of the planar dielectric 208) when the second blade element 207 is moved to the closed position. The second electrode 214 extends along the inner lateral surface of the movable portion 212. The second blade element 207 and the movable portion 212 can be formed from a conductive material coated with an insulating material. For example, they can be made from stainless steel coated with ceramic (e.g., alumina), diamond-like carbon (DLC) coating, enamel coating, or silicone-based paint. The material can then be further coated with Parylene N to seal the insulating coating. For example, the Parylene N coating can have a thickness of between 2 and 10 micrometers, preferably between about 3 and 7 micrometers, and more preferably about 5 micrometers. The Parylene N coating penetrates the pores of the insulating coating, effectively increasing its waterproofing. This in turn increases the breakdown voltage when the insulator coating becomes wet. The insulating and Parylene-N coatings can be removed, for example, by etching, from areas where they are not needed. For example, the second electrode 214 may be formed by etching away the insulating and Parylene-N coatings from the inner bottom edge of the movable portion 212. A layer of gold may be deposited on the etched surface to form the electrode. Other portions of the coating may be removed to allow electrical connection to the outer conductor of the coaxial cable, as described below.

[0059] The flexible shaft 204 defines a lumen through which extend a coaxial cable (not shown) for transmitting EM energy (e.g., RF and / or microwave EM energy) and a longitudinally slidable control rod (shown in FIG. 2C) for controlling the movement of the movable portion 212.

[0060] As will be described in more detail with reference to Figure 4, the first electrode 206 is electrically connected to the inner conductor of a coaxial cable inside the shaft 204, and the second electrode 214 is electrically connected to the outer conductor of the coaxial cable. Thus, the instrument tip provides an energy delivery structure operable to deliver EM energy. For example, RF energy may be delivered along a current path between the first and second electrodes (e.g., through tissue) and / or microwave energy may be delivered via a microwave field emitted by the first and second electrodes.

[0061] The instrument tip 200 can provide three modes of operation. In a first mode, the instrument can be used with the blade elements 205, 207 in a closed position to deliver RFEM energy to cut biological tissue. In this first mode, the RFEM energy passes primarily between the first electrode 206 and the second electrode 214 in the distal cutting zone 230 adjacent the upstanding teeth 210 on the first blade element 205 and the depending teeth 216 on the second blade element 207 (see, e.g., FIG. 2A ). Thus, the instrument can be used to sweep or slide across or through tissue to create a cut.

[0062] In a second mode, the blade elements 205, 207 can be used to perform a grasping cut, i.e., a cut through tissue captured between the blade elements, in which the cut is performed by a combination of physical pressure exerted by closing the blade elements 205, 207 and RFEM energy applied during this closing process.

[0063] In a third mode, the blade elements 205, 207 can be used to grasp and seal tissue, such as blood vessels or the like. In this mode, microwave EM energy is supplied to the electrodes, which produce a microwave field that acts to coagulate tissue held within the blade elements.

[0064] The stationary portion 202 can have a dielectric shield attached to its outer surface. In this example, the dielectric shield is a thermoplastic polymer, such as polyetheretherketone (PEEK). The dielectric shield can be molded onto the device, or it can be a cover (e.g., formed by laser cutting an appropriately sized tube) that slides over the instrument tip when the blade elements are in the closed position. The dielectric shield can be used to control the shape of the first electrode 206, for example, to ensure that the first electrode 206 is substantially only exposed at the top surface of the first blade element 205. This in turn ensures that the EM energy (e.g., RF and / or microwave energy) delivered from the electrode is focused in a desired area.

[0065] Next, the opening and closing operation of the device distal end portion 200 will be described with reference to FIGS. 2A to 2D. 2C and 2D show the instrument tip 200 in an open position with the movable section 212 positioned such that the second blade element 207 is at an acute angle (e.g., 60 degrees) relative to the first blade element 205. As best shown in FIG. 2A, the stationary section 202 includes a longitudinally extending arm 218 that provides a pivot base for the movable section 212. The arm 218 has a pivot axle (not shown) rotatably mounted thereon. The pivot axle defines a laterally extending pivot axis 219 (i.e., the pivot axis is perpendicular to the longitudinal direction defined by the flexible shaft 204).

[0066] The support arm 218 is formed on the stationary portion 202 to define a slot in the stationary portion 202. The slot may be necessary to provide space for a portion of the movable portion 212 (e.g., a proximal portion, such as the mounting plate 222) to move relative to the stationary portion 202 as the movable portion 212 moves between the open and closed positions. The stationary portion 202 and the support arm 218 may form part of an electrical connection between a conductor in the shaft 204 and the second electrode 214. For example, the stationary portion 202 (e.g., the support arm 218) may be formed from an insulator-coated conductive material that is further coated with Parylene N, and may include a proximal contact portion where the insulator coating and Parylene N coating are removed and electrically connected to the conductor in the shaft 204. For example, the Parylene N coating may have a thickness between 2 and 10 micrometers, preferably between about 3 and 7 micrometers, and more preferably about 5 micrometers. As described above, the Parylene N coating may be used to improve waterproofing and increase the breakdown voltage of the insulating coating in wet conditions. To facilitate the creation of a coating that covers the required area of ​​the stationary portion 202 and is uniform, it may be beneficial to limit certain dimensions of the slot so that the coating material can penetrate all interior surfaces of the slot. Accordingly, the length of the slot (i.e., the dimension along the length of the shaft 204) may be between 1 mm and 3 mm (preferably less than 2 mm). The width of the slot (i.e., the dimension along the pivot axis 219) may be between 0.2 mm and 1.2 mm (preferably greater than 0.7 mm). The depth of the slot may be between 0.2 mm and 1.2 mm (preferably greater than 0.6 mm).

[0067] A slidable control rod 220 protrudes from the flexible shaft 204. The stationary portion 202 has a guide channel (not shown) formed therein through which the control rod 220 passes. The control rod 220 has a distal attachment mechanism 223 that engages with the movable portion 212. In this embodiment, the distal attachment mechanism 223 is a hook that engages with a circular opening 224 formed in a mounting plate 222 of the movable portion 212. Other types of engagement may be used. Longitudinal sliding movement of the control rod 220 is translated into pivotal movement of the mounting plate 222. The mounting plate 222 may be integrally formed with the second blade element 207 or may be otherwise operatively coupled to the second blade element 207. The attachment mechanism 223 and opening 224 may be configured to substantially prevent longitudinal movement of the attachment mechanism 223 in the opening 224. For example, the diameter of the control rod can be made very slightly smaller than the diameter of the opening 224 so that the attachment mechanism 223 can rotate within the opening 224 but cannot move longitudinally within the opening 224. In this way, all longitudinal movement of the control rod can be translated into movement of the jaws.

[0068] Figures 2A and 2B show the instrument tip 200 in a closed position. Movement from the open position of Figures 2C and 2D to the closed position of Figures 2A and 2B is accomplished by retracting the control rod 220 into the flexible sleeve 204, for example, through a handpiece such as handpiece 106 of Figure 1.

[0069] 2A-2D also show a travel limiting mechanism for the instrument tip 200. The travel limiting mechanism functions to limit the maximum range of relative motion between the second blade element 207 and the first blade element 205 in the open and closed positions.

[0070] 2B and 2C, stationary portion 202 and movable portion 212 include at least one pair of cooperating structures arranged to collectively provide a travel-limiting mechanism. The first pair of cooperating structures includes a raised protrusion (or shoulder) 240 and a cooperating stop surface 242. Raised protrusion 240 is formed on the upper surface of movable portion 212 distal to the connection between the movable and stationary portions (e.g., distal to pivot axis 219). Stop surface 242 is also formed on the upper surface of stationary portion 202 proximal to the connection between the movable and stationary portions. In an embodiment, stop surface 242 is formed on the upper surface of support arm 218 of stationary portion 202.

[0071] As seen in FIG. 2C , during use, the raised protrusion 240 and the stop surface 242 are configured to abut one another in the open position. In this manner, the first pair of cooperating structures limits the maximum range of relative motion between the second blade element 207 and the first blade element 205 in the open position. That is, the first pair of cooperating structures limits the width to which the jaws can open. In embodiments, the first pair of cooperating structures is configured (e.g., sized, shaped, and positioned) to limit the maximum angle between the first blade element and the second blade element to approximately 60 degrees. Note that, without the first pair of cooperating structures, the jaws may be able to open more widely. Thus, the first pair of cooperating structures can limit the width to which the jaws can open to ensure that operation (e.g., movement) of the jaws is uniform and reliable throughout the allowed range of movement. For example, without the first pair of cooperating structures, the extreme limits of the second blade element's range of motion may become jerky, placing proportionally greater strain on the instrument tip compared to the middle of the range of motion. Therefore, limiting the maximum extent to which the second blade element can rotate away from the first blade element can maintain a more uniform and reliable overall jaw movement. Additionally, it may be desirable to limit the distance the jaws can open to prevent them from becoming stuck or locked in the open position. Furthermore, it may be desirable to limit the distance the jaws can open so that the overall profile of the instrument tip can be kept small, which may be beneficial in tight spaces or locations. Such benefits are particularly important in precision surgical procedures.

[0072] In the illustrated embodiment, the movable portion includes a raised protrusion and the stationary portion includes a stop surface. However, it will be understood that in at least some other embodiments, the raised protrusion may be disposed on the stationary portion and the stop surface may be disposed on the movable portion. Furthermore, in some other embodiments, the first pair of cooperating structures may include two raised protrusions rather than a raised protrusion and a stop surface.

[0073] Additionally, the travel limiting mechanism may include a second pair of cooperating structures including a pair of abutment surfaces 246 and 248. Abutment surface 246 is formed on an upper surface of movable portion 212 proximal to the connection between movable portion 212 and stationary portion 202 (e.g., proximal to pivot axis 219). Abutment surface 248 is formed on a lower surface of stationary portion 202 proximal to the connection between movable portion 212 and stationary portion 202. In an embodiment, abutment surface 248 is formed on the underside of support arm 218.

[0074] 2B , during use, the second pair of cooperating structures are configured to be parallel and abutting each other in the closed position. That is, in the closed position, abutment surface 246 is substantially parallel to and in contact with abutment surface 248. In this manner, movable portion 212 and second blade element 207 are prevented from further movement past stationary portion 202 and first blade element 205. Thus, the second pair of cooperating structures limits the relative position of movable portion 212 and second blade element 207 with respect to stationary portion 202 and first blade element 205 in the closed position. For example, the second pair of cooperating structures may be configured (e.g., sized, shaped, and positioned) to ensure that second blade element 207 (e.g., teeth 216 and / or teeth 217) does not protrude below planar dielectric 208 in the closed position. For example, the dimensions (e.g., length or width) of mounting plate 222 may be set to define the closed position. It should be noted that, without the second pair of cooperating structures, the second blade element 207 may be able to protrude below the bottom surface of the planar dielectric 208 (e.g., considering the orientation shown in FIG. 2B ). This may be undesirable as it may cause unintended damage to tissue located below the instrument tip 200. Additionally, if the second blade element 207 were allowed to pivot downwardly past the planar dielectric 208, subsequent jaw opening could unintendedly cut tissue located between the top surface of the distal tip of the movable portion 212 and the bottom surface of the distal tip of the stationary portion 202.

[0075] Figures 3A and 3B show the mechanism for coupling the control rod 220 to the instrument tip 200. In Figures 3A and 3B, the outer sleeve of the shaft 204 has been omitted for clarity, allowing the elements underneath to be seen. It will be understood that after the arrangement of Figures 3A and 3B is formed, an outer sleeve will be added, as shown in Figures 2A-2C.

[0076] In Figures 3A and 3B, the elements of the instrument tip 200 are as described above and are indicated with corresponding reference symbols. Figures 3A and 3B show how the control rod 220 extends from its connection with the movable portion 212 into the shaft. Additionally, the stationary portion 202 includes a guide channel 250 that receives the control rod 220. At least a portion of the guide channel 250 may be substantially U-shaped to accommodate the control rod 220. A coaxial cable 248 can be seen behind the control rod 220 along the length of the shaft. As described below with reference to Figures 6A and 6B, the control rod 220 extends along the shaft 204 within a guidewire tube (also known as a first tube) 252. The guidewire tube 252 ensures smooth (i.e., reduced friction) movement of the control rod 220 within the shaft 204. The proximal end of the guidewire tube 252 terminates at or within a handpiece (e.g., handpiece 106 of Figure 1). The distal end of guidewire tube 252 terminates at (i.e., just before) the proximal end of stationary portion 202, as shown in FIGS. 3A and 3B. Proximal end region 254 of stationary portion 202 may have a generally circular cross-section and may have a reduced width (e.g., diameter) compared to the features of stationary portion 202 disposed distally therefrom. Proximal end region 254 may also include one or more surface ribs. Because the distal end of guidewire tube 252 terminates just before the proximal end of stationary portion 202, guidewire tube 252 surrounds most or all of control rod 220 except for the distal end region of control rod 220. The distal end region of control rod 220 may be the last 4 mm to 8 mm.

[0077] Distal guidewire tube (also known as second tube) 256 surrounds the distal end region of control rod 220, excluding attachment mechanism 223 of control rod 220. The attachment mechanism may correspond to the distal-most 2 mm or less of control rod 220. Distal guidewire tube 256 also protrudes proximally into guidewire tube 252, defining an overlap region 258 where guidewire tube 252 overlaps distal guidewire tube 256. The length of overlap region 258 may be approximately half the length of distal guidewire tube 256; for example, overlap region 250 may be approximately 4 mm to 6 mm long, and distal guidewire tube 256 may be approximately 8 mm to 12 mm long.

[0078] The proximal short tube (also known as the third tube) 260 surrounds the overlap region 258 and a proximal portion of the proximal end region 254 of the stationary portion 202. The proximal short tube 260 fits around the proximal end region 254 and may be held in place by a frictional engagement reinforced by the aforementioned ribs. The length of the overlap region 258 may be approximately half the length of the proximal short tube 260, and the proximal end of the proximal short tube 260 may extend proximally past the proximal end of the overlap region 258. For example, the overlap region 258 may be approximately 4 mm to 6 mm long, and the length of the proximal short tube 260 may be approximately 8 mm to 12 mm long. The proximal short tube 260 is then bonded to the proximal end region 254 and both the guidewire tube 252 and the distal guidewire tube 256. For example, the bonding may be via an interference fit and / or adhesive. In an embodiment, the three tubes are transparent and are bonded to each other and to the proximal end region 254 using an ultraviolet adhesive. The aforementioned rib feature on the proximal end region 254 may help ensure that the base stub tube 260 remains attached to the stationary portion 202.

[0079] Thus, control rod 220 slides freely within the channel formed by guidewire tube 252 and distal guidewire tube 256. As such, control rod 220 does not catch on or become entangled with any features as it is deployed and retracted within shaft 204 to open and close the jaws. Also, because this channel extends through the connection between shaft 204 and stationary portion 202, it similarly results in preventing catches and entanglements as control rod 220 moves relative to stationary portion 202. Furthermore, because proximal stub tube 260 secures the channel relative to instrument tip 200, the channel cannot move relative to instrument tip 200. As a result, this ensures that the movement of control rod 220 remains smooth and uniform.

[0080] Note that as a final step, the outer sleeve of shaft 204 is placed over the top of proximal stub tube 206, as shown in Figures 2A-2C. The outer sleeve may be bonded in place with an adhesive. In embodiments, guidewire tube 252 and distal guidewire tube 256 may be formed from PTFE or the like, while the proximal stub tube may be formed from polyether block amide (also known as PEBA, PEBAX, or thermoplastic elastomer).

[0081] 4 is a schematic, partially cutaway side view of an instrument tip 300 for an electrosurgical ablation instrument according to an embodiment of the present invention. The instrument tip 300 is at the distal end of a flexible sleeve 302 that carries a coaxial cable 304 and a control rod 312. The control rod 312 is for controlling the pivotal movement of a movable portion 322 relative to a stationary portion 318, in a manner similar to that described above. The stationary portion 318 has a planar dielectric 314 secured thereto, for example by a suitable adhesive, and extending longitudinally away from the stationary portion 318 to form a first blade element. A first electrode 316 is formed on one side of the planar dielectric 314.

[0082] The movable portion 322 is pivotally mounted to the stationary portion 318 via a pivot axle (not visible in FIG. 4 ) on the opposite side of the planar dielectric 314 from the first electrode 316. The movable portion 322 includes a second blade element arranged to slide past the first blade element, similar to the first and second blade elements 205, 207 described above. The movable portion 322 includes a second electrode 324 located thereon adjacent the opposite side of the planar dielectric 314 when the blade elements are in the closed position.

[0083] Coaxial cable 304 includes an inner conductor 306 separated from an outer conductor 310 by a dielectric material 308. Dielectric material 308 and inner conductor 306 extend beyond the distal end of outer conductor 310. The distal end of dielectric material 308 abuts the proximal end of planar dielectric 314. Inner conductor 306 extends distally from this junction to overlap and electrically contact a proximal portion of first electrode 316. The invention need not be limited to this arrangement. In other embodiments, the inner conductor may be electrically connected to an electrode on the movable portion, for example.

[0084] The stationary body 318 includes a support arm to which the movable portion is attached. The planar dielectric 314 may also be attached to the support arm using, for example, an adhesive. The stationary portion (e.g., the support arm) is formed from a conductive material (e.g., stainless steel) with an electrically insulating coating. As described above, this insulating coating may be further coated with Parylene N to improve waterproofing and increase the breakdown voltage of the insulating coating in wet conditions. The coating is removed at the proximal contact portion 320, which is electrically connected to the outer conductor 310 of the coaxial cable 304. The movable portion 322 is also formed from a conductive material (e.g., stainless steel) with an electrically insulating coating. Again, this insulating coating may be further coated with Parylene N. The movable portion 322 is physically engaged with the stationary portion 318 at a pivot connection. The electrical connection between the second electrode 324 and the outer conductor 310 of the coaxial cable 304 passes through the pivot connection. For example, the pivot axle itself may be formed from a conductive material (e.g., stainless steel). The insulating coating and Parylene-N coating of the stationary part 318 may be removed in the area of ​​sliding engagement between the stationary part 318 and the movable part 322 (e.g., an opening or recess for receiving a pivot axle). Similarly, the insulating coating and Parylene-N coating of the movable part 322 may be removed in this area. The second electrode 324 may be the conductive material of the movable part 322 or may be electrically connected to the conductive material of the movable part 322, so that a complete electrical connection to an external conductor can be formed.

[0085] Figure 5 is a reproduction of Figure 2D, showing shaft 302 as partially transparent to illustrate how the schematic features of Figure 4 can be mapped onto the device shown in Figures 2A-2D. Features in common with Figure 4 are given the same reference numerals and will not be described again.

[0086] FIG. 6A is a cutaway perspective view of the instrument shaft 612 as it moves toward the instrument tip. The instrument shaft 612 includes an outer sleeve 648 defining lumens for carrying the coaxial cable 626 and the control rod 636. In this embodiment, the coaxial cable 626 and the control rod 636 are retained within a longitudinally extending insert 650. The insert 650 is an extrusion formed from a deformable polymer such as PEEK or other plastic with similar mechanical properties. As shown more clearly in FIG. 6B, the insert 650 is a cylindrical element having a series of secondary lumens 664 cut out around its outer surface. The secondary lumens 664 penetrate the outer surface of the insert 650 to define a plurality of discrete legs 662 around its circumference. The secondary lumens 664 can be sized to carry components such as the coaxial cable 626 or the control rod 636, or can be for allowing fluid flow along the lumen of the sleeve 648.

[0087] It may be beneficial for the insert to not include any enclosed secondary lumens at all. Fully enclosed secondary lumens tend to retain deformation when stored in a bent state. Such deformation can result in jerky movement during use.

[0088] The insert 650 may include a secondary lumen for receiving the coaxial cable 626. In this example, the coaxial cable 626 includes an inner conductor 658 separated from an outer conductor 654 by a dielectric material 656. The outer conductor 654 may have a protective cover or sheath 652 formed, for example, from PTFE or other suitable low-friction material, to allow relative longitudinal movement between the insert and the coaxial cable as the shaft undergoes flexion.

[0089] Another secondary lumen may be arranged to receive a standard PFTE tube 660 (which may be the guidewire tube 252 of FIGS. 3A and 3B) through which the control rod 636 extends. In an alternative embodiment, the control rod 636 may be provided with a low-friction (e.g., PFTE) coating prior to use, in which case a separate PFTE tube is not required.

[0090] The insert is positioned to fill, i.e., fit snugly within, the lumen of sleeve 648 when installed along with coaxial cable 626 and control rod 636. That is, the insert functions to limit relative motion between the coaxial cable, control rod, and sleeve as shaft 612 flexes and rotates. Additionally, by filling sleeve 648, the insert helps prevent the sleeve from collapsing and losing rotation if over-rotated. The insert is preferably made from a material that exhibits the rigidity to withstand such movement.

[0091] The presence of the insert may further prevent “wasteful” movement of the control rod caused by deformation of the instrument shaft 612 .

[0092] The extrusion insert also provides a cam-like foot that packs inside the sleeve and prevents the control rod from wrapping around the axis of the sleeve, thereby reducing the wasted travel discussed above.

Claims

1. a shaft defining a lumen; an energy transmission structure for transmitting electromagnetic (EM) energy through the lumen of the shaft; an instrument tip attached to a distal end of the shaft, the instrument tip comprising: a stationary portion including a first blade element; a movable part including a second blade element, the movable part being movable relative to the stationary part between a closed position in which the first blade element and the second blade element are positioned alongside each other, and an open position in which the second blade element is spaced apart from the first blade element by a gap for receiving biological tissue; a movement limiting mechanism operable to limit a maximum range of relative movement between the second blade element and the first blade element in the open position, the stationary portion and the movable portion comprise at least one pair of cooperating structures arranged to together provide the movement limiting mechanism; the travel limiting mechanism, wherein a first pair of cooperating structures comprises a raised protrusion and a cooperating stop surface, the raised protrusion and the cooperating stop surface being configured to abut one another in the open position in use; a first electrode, a second electrode, and a planar dielectric, the first electrode and the second electrode being spaced apart and electrically isolated from one another by the planar dielectric, the first electrode and the second electrode being connected to the energy transfer structure for delivering the EM energy from the device tip; the instrument tip portion comprising: an actuator for controlling relative motion between the movable part and the stationary part; Equipped with An electrosurgical cutting instrument, wherein the travel limiting mechanism is arranged to limit a maximum angle between the first blade element and the second blade element to an acute angle.

2. the movement limiting mechanism is operable in the closed position to limit the maximum range of relative movement between the second blade element and the first blade element; 2. The electrosurgical ablation instrument of claim 1, wherein the second pair of cooperating structures includes a pair of abutment surfaces configured to be parallel disposed and abutting each other in the closed position, in use.

3. 3. An electrosurgical cutting instrument according to claim 1 or 2, wherein the movable portion includes the raised protrusion and the stationary portion includes the cooperating stop surface.

4. 4. An electrosurgical cutting instrument according to claim 1, wherein the movable part is pivotable relative to the stationary part such that the second blade element is angled relative to the first blade element in the open position, and wherein in the open position the travel-limiting mechanism is arranged to limit the maximum angle between the first and second blade elements to 60 degrees.

5. An electrosurgical cutting instrument as described in any one of claims 1 to 4, wherein the raised protrusion is formed on the upper surface of the movable part distal to the connection between the movable part and the stationary part, and the cooperating stop surface is formed on the upper surface of the stationary part proximal to the connection between the movable part and the stationary part.

6. a shaft defining a lumen; an energy transmission structure for transmitting electromagnetic (EM) energy through the lumen of the shaft; an instrument tip attached to a distal end of the shaft, the instrument tip comprising: a stationary portion including a first blade element; a movable part including a second blade element, the movable part being movable relative to the stationary part between a closed position in which the first blade element and the second blade element are positioned alongside each other, and an open position in which the second blade element is spaced apart from the first blade element by a gap for receiving biological tissue; a movement limiting mechanism operable to limit a maximum range of relative movement between the second blade element and the first blade element in the closed position, the stationary portion and the movable portion comprise at least one pair of cooperating structures arranged to together provide the movement limiting mechanism; the movement limiting mechanism, wherein a first pair of cooperating structures includes a pair of abutment surfaces, the pair of abutment surfaces being configured to be arranged parallel and abut each other in the closed position in use; a first electrode, a second electrode, and a planar dielectric, the first electrode and the second electrode being spaced apart and electrically isolated from one another by the planar dielectric, the first electrode and the second electrode being connected to the energy transfer structure for delivering the EM energy from the device tip; the instrument tip portion comprising: an actuator for controlling relative motion between the movable part and the stationary part; Equipped with an electrosurgical cutting instrument, wherein a first abutment surface of the pair of abutment surfaces is formed on an upper surface of the movable portion proximal to a connection between the movable portion and the stationary portion, and a second abutment surface of the pair of abutment surfaces is formed on a lower surface of the stationary portion proximal to the connection between the movable portion and the stationary portion.

7. 6. An electrosurgical cutting instrument according to claim 2, wherein a first abutment surface of the pair of abutment surfaces is formed on an upper surface of the movable part proximal to the connection between the movable part and the stationary part, and a second abutment surface of the pair of abutment surfaces is formed on a lower surface of the stationary part proximal to the connection between the movable part and the stationary part.

8. 8. An electrosurgical cutting instrument according to claim 1, wherein one of the first and second blade elements comprises a longitudinally extending planar dielectric having the first electrode on a first lateral surface thereof, and wherein in the closed position the other of the first and second blade elements is located adjacent a second lateral surface of the longitudinally extending planar dielectric opposite the first lateral surface thereof.

9. The electrosurgical cutting instrument of claim 8 , wherein the second electrode is disposed on the second lateral surface of the longitudinally extending planar dielectric.

10. 9. The electrosurgical cutting instrument of claim 8, wherein the longitudinally extending planar dielectric is on the first blade element and the second electrode extends along a side of the second blade element.

11. 11. The electrosurgical cutting instrument of claim 10, wherein the second blade element comprises a conductive material, an insulator coating on the conductive material, and a Parylene N coating on the insulator coating, and the second electrode is formed on a side portion of the second blade element from which the insulator coating and the Parylene N coating have been removed.

12. An electrosurgical cutting instrument according to any preceding claim, wherein the stationary portion includes a support arm to which the movable portion is attached.

13. The support arm defines a slot in the stationary portion for receiving a portion of the movable portion, the slot comprising: The slot has a length of less than 2 mm. The width of the slot is greater than 0.7 mm. The electrosurgical ablation instrument of claim 12, wherein at least one of the following applies: the depth of the slot is greater than 0.6 mm.

14. 14. An electrosurgical ablation instrument according to claim 12 or claim 13, wherein the stationary portion comprises a conductive material, an insulator coating on the conductive material, and a Parylene N coating on the insulator coating, and the support arm includes a proximal contact portion from which the insulator coating and the Parylene N coating are removed to form a portion of an electrical connection between the energy transfer structure and the second electrode.

15. 15. An electrosurgical ablation instrument according to any preceding claim, wherein the actuator includes a control rod slidably mounted on the shaft, the control rod having an attachment mechanism that engages the movable portion such that longitudinal movement of the control rod within the shaft causes movement of the movable portion relative to the stationary portion.

16. 16. The electrosurgical ablation instrument of claim 15, further comprising a first tube, a second tube, and a third tube, wherein the first tube surrounds the control rod except for a distal end region thereof, the second tube surrounds the distal end region of the control rod except for the attachment mechanism of the control rod, the second tube projects proximally into the first tube to define an overlap region where the first tube overlaps the second tube, and the third tube surrounds the overlap region and a proximal end region of the stationary portion.

17. 17. The electrosurgical ablation instrument of claim 16, wherein the first, second and third tubes are substantially transparent and are bonded to the instrument tip with an ultraviolet adhesive.

18. the energy transfer structure includes a coaxial transmission line extending longitudinally through the lumen, the coaxial transmission line including an inner conductor separated from an outer conductor by a dielectric material; 18. The electrosurgical ablation instrument of any preceding claim, wherein the inner conductor is connected to one of the first electrode and the second electrode and the outer conductor is connected to the other of the first electrode and the second electrode for delivering the EM energy from the instrument tip.

19. the energy transfer structure is for transferring radio frequency (RF) electromagnetic (EM) energy and microwave EM energy; The first electrode and the second electrode are an active electrode and a return electrode for delivering the RF energy transmitted from the energy transmission structure; and a microwave field emission structure for transmitting microwave energy transmitted from the energy transmission structure; An electrosurgical cutting instrument according to any preceding claim, operable as follows:

20. an electrosurgical generator for supplying electromagnetic (EM) energy; a surgical scope device having an instrument cord for insertion into a patient's body, the instrument cord having an instrument channel extending therethrough; 20. An electrosurgical ablation instrument according to claim 19 inserted through the instrument channel of the surgical scope device; An electrosurgical device comprising:

21. 21. The electrosurgical device of claim 20, wherein the electrosurgical generator is capable of providing radio frequency (RF) EM energy and microwave EM energy.

22. a shaft defining a lumen; an energy transmission structure for transmitting electromagnetic (EM) energy through the lumen of the shaft; an instrument tip attached to a distal end of the shaft, the instrument tip comprising: a stationary portion including a first blade element; a movable part including a second blade element, the movable part being movable relative to the stationary part between a closed position in which the first blade element and the second blade element are positioned alongside each other, and an open position in which the second blade element is spaced apart from the first blade element by a gap for receiving biological tissue; a first electrode, a second electrode, and a planar dielectric, the first electrode and the second electrode being spaced apart and electrically isolated from one another by the planar dielectric, the first electrode and the second electrode being connected to the energy transfer structure for delivering the EM energy from the device tip. the device tip; an actuator for controlling relative motion between the movable part and the stationary part, the actuator including a control rod slidably mounted on the shaft, the control rod having an attachment mechanism that engages the movable part, whereby longitudinal movement of the control rod within the shaft causes movement of the movable part relative to the stationary part; a first tube, a second tube, and a third tube, wherein the first tube surrounds the control rod except for a distal end region of the control rod, the second tube surrounds the distal end region of the control rod except for the attachment mechanism of the control rod, the second tube protrudes proximally into the first tube to define an overlap region where the first tube overlaps the second tube, and the third tube surrounds the overlap region and a proximal end region of the stationary portion; 1. An electrosurgical ablation instrument comprising:

23. 23. The electrosurgical ablation instrument of claim 22, wherein the first, second and third tubes are substantially transparent and are bonded to the instrument tip with an ultraviolet adhesive.

24. 24. An electrosurgical ablation instrument according to claim 22 or claim 23, wherein the instrument tip further comprises a travel limiting mechanism operable to limit the maximum range of relative movement between the second blade element and the first blade element in the open position and / or the closed position.

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