Electrosurgical device with a distal opening

Abstract

A method and apparatus are provided for delivering fluid forward through an electrosurgical device while preventing coring when delivering energy to the electrosurgical device. The device has a distal surface defining an opening, the distal surface including at least one cutting portion and at least one non-cutting portion. An embodiment of an electrosurgical device for piercing tissue includes an elongate member defining a lumen for receiving fluid, a distal surface defining at least one opening, the distal surface including at least one cutting portion and at least one non-cutting portion, which cooperate to effect an elongate cut in the tissue when electrical energy is delivered to the distal surface while preventing coring of the tissue.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the benefit of priority of International Application No. PCT / IB2014 / 059641, filed on March 11, 2014, the entire disclosure of which is incorporated herein by reference.

[0002] The present disclosure relates to methods and devices that can be used for energy delivery into a patient's body. More particularly, the present invention relates to an electrosurgical piercing device.

Summary of the Invention

[0003] Disclosed herein are embodiments of a surgical device that, while achieving elongation (non - circular) piercing, dilation, and forward fluid delivery, prevents core - drilling. The device generally comprises a distal face that defines an opening, and the distal face of the device includes at least one elongated cutting portion and at least one non - cutting portion.

[0004] In a broad aspect, embodiments of the present disclosure include an electrosurgical device for piercing tissue, the electrosurgical device comprising: an elongated member defining a lumen for receiving fluid; and a distal face defining at least one opening, the distal face including at least one cutting portion and at least one non - cutting portion, the at least one cutting portion and the at least one non - cutting portion cooperating such that when electrical energy is delivered to the distal face, an elongated cut is created in the tissue while preventing core - drilling of the tissue.

[0005] As a feature of this aspect, some embodiments include at least one cutting portion, and at least one cutting portion is substantially arcuate and is located along the inner surface of the elongated member.

[0006] As another feature of this aspect, some embodiments include a distal end of the elongate member, the distal end of the elongate member being asymmetrically cut at the tip so as to define a stepped distal surface, the stepped distal surface having a leading portion and a recessed portion, the leading portion having at least one cut portion, and the recessed portion having at least one non-cut portion.

[0007] As another feature of this aspect, some embodiments further include a protruding electrode that defines a leading surface at the distal end of the elongate member, the leading surface including at least one cut portion.

[0008] As another feature of this aspect, some embodiments include at least one cut portion that is arcuate and partially surrounds an opening, the at least one cut portion including at least one active electrode and at least one return electrode operable to deliver energy bipolarly.

[0009] As yet another feature of this aspect, some embodiments include at least one cut portion, the at least one cut portion including an active electrode and a return electrode that are parallel to each other and extend substantially across the opening, the active electrode and the return electrode being operable to deliver energy bipolarly.

[0010] As another feature of this aspect, some embodiments include an elongate member, the elongate member including a conductive tubular member at least partially covered by an insulating material, and at least one non-cut portion of the distal surface including an insulating layer.

[0011] As another feature of this aspect, some embodiments include an elongate member, the elongate member including a conductive tubular member at least partially covered by an insulating material, the conductive tubular member having a notch portion proximal to the distal surface, the electrosurgical device further including an insulating insert located in the notch portion, the distal surface of the electrosurgical device including the distal surface of the tubular member, the distal surface of the tubular member defining at least one cut portion, and the distal surface of the insulating insert defining at least a portion of at least one non-cut portion.

[0012] In another broad aspect, embodiments of the present invention include an electrosurgical device for piercing tissue, the electrosurgical device comprising: an elongate member defining a lumen for receiving fluid and comprising a non-conductive material; and a distal surface defining an opening, the distal surface including at least one cut portion and at least one non-cut portion, the at least one cut portion and the at least one non-cut portion cooperating to produce an elongate cut in the tissue when electrical energy is delivered to the distal surface while configured to prevent coaxialization of the tissue.

[0013] In another broad aspect, embodiments of the present invention include an electrosurgical device for piercing tissue, the electrosurgical device comprising: an elongate member defining a lumen for receiving fluid; and a distal surface of the elongate member defining an opening and a conductive portion at least partially surrounding the opening, the conductive portion defining a biased electrode configured to produce a non-coaxializing cut in the tissue when energy is delivered to the distal surface.

[0014] To facilitate understanding of the present invention, embodiments of the present invention in the accompanying drawings are shown by way of example.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2a

Figure 2b

Figure 2c

Figure 3a

Figure 3b

Figure 3c

Figure 3d

Figure 4a

Figure 4b

Figure 4c

Figure 4d

Figure 4e

Figure 4f

Figure 4g

Figure 5a

Figure 5b

Figure 5c

Figure 6a

Figure 6b

Figure 7a

Figure 7b

Figure 7c

Figure 8

Figure 9a

Figure 9b

Figure 10a

Figure 10b

Figure 11

Figure 12

Figure 13a

Figure 13b

DETAILED DESCRIPTION OF THE INVENTION

[0016] Devices used for puncturing tissue, such as transseptal tissue of a patient's heart, are typically either mechanical devices or electrosurgical devices. Some electrosurgical devices incorporate side ports and do not have a forward lumen opening, so, for example, when the device is confined inside an expander lumen where it fits tightly, it is not possible to effectively inject fluid or monitor fluid pressure. Further, in some cases, a guide wire can be passed through the side port and accepted by the side port, but generally, devices without a forward opening are not easily used with a guide wire. In contrast, devices having a forward opening are typically more effective for fluid injection and pressure monitoring and typically make it easier to use a guide wire than side port devices.

[0017] Conventional Brockenbrough transseptal needles having an acutely angled tip have a forward-facing opening and can be used for fluid injection or pressure monitoring. However, conventional transseptal needles typically use mechanical force for tissue puncture, and this force is not effective for tissue puncture in some situations. To address the problem of tissue puncture that does not facilitate mechanical puncture, some physicians have used an electrosurgical generator or the like to charge a mechanical needle and thereby create a dedicated electrosurgical device having a forward-facing opening. One drawback of charging a Brockenbrough needle is the risk of tissue coring. A tissue core (or plug) is typically excised from the surrounding tissue during energy delivery and then taken into the lumen of the electrosurgical device as the needle advances through the tissue. The tissue core can be released from the lumen by flushing, but in some cases, it can cause embolization, increasing the risk of stroke or some other ischemic event. Additionally, a charged Brockenbrough needle without insulation poses an increased risk of further hazards such as burns to the patient and the physician.

[0018] The present disclosure includes various embodiments of an electrosurgical device that includes a distal face that provides an elongated first puncture portion, the elongated first puncture portion being configured to expand when the device is advanced while reducing the risks of tissue coring and embolization. Embodiments of the device also have a forward-facing lumen opening, enable pressure monitoring, forward delivery of fluid, and facilitate use with a guide wire.

[0019] In a typical embodiment, the distal surface of the electrode defines at least one elongated portion (when viewed from the end), and the device provides at least one elongated portion and a corresponding puncture portion, thereby defining a flap of one or more tissues, which flap can be laterally displaced by the distal surface of the device when the device is advanced. The term "elongated electrode" is used to describe an electrode that is non-circular and has one dimension longer than the other. In some embodiments, the distal surface of the electrode generally defines an elongated shape that is C-shaped, U-shaped, semi-circular, shaped like a segment of a circle, shaped like an arc, arcuate, crescent-shaped, rectangular-shaped, generally straight, or star-shaped (i.e., having segments radiating from a central point). Some embodiments have a pair of generally parallel electrodes that are generally straight (or rectangular-shaped) and are operable to deliver bipolar energy. While the present disclosure describes an electrosurgical device having a generally circular cross-section, the concepts and claims of the present disclosure apply to non-circular devices, such as square-shaped or oval-shaped devices. Further, some embodiments are configured such that the electrode used for tissue puncture does not completely surround or enclose the forward lumen opening, thereby avoiding having a ring-shaped electrode that could cause tissue coring.

[0020] Accordingly, the inventors have devised and come to implement a surgical device for puncturing tissues such as the atrial septum, which enables forward fluid delivery for septum coloring and has a lower risk of tissue coring compared to a charged Brockenbrough needle or similar device. The device includes a distal surface that defines at least one opening, the distal surface including at least one cut portion and at least one non-cut portion, the at least one cut portion and the at least one non-cut portion cooperating to provide an elongated cut in the tissue when electrical energy is delivered to the distal surface while preventing tissue coring. A typical embodiment can be advanced over a guide wire to the treatment site.

[0021] Next, with specific reference to the drawings, it is emphasized that the matters shown are by way of example only and are for the purpose of illustrative explanation of specific embodiments of the present invention. Before explaining the embodiments of the present invention in detail, it should be understood that the present invention is not limited to the structural details and the configurations of the components shown in the following description or drawings. The present invention is capable of other embodiments or of being practiced or carried out in various ways. Also, it should be understood that the language and terminology used herein are for the purpose of description and should not be regarded as limiting.

[0022] FIG. 1 is a diagram of one embodiment of a device including a handle and a shaft. The electrosurgical device 120 of FIG. 1 is composed of an elongate member 102, an insulating material 105, and a distal portion 110. The handle 101 is mechanically coupled to the proximal end of the elongate member 102. The elongate member 102 defines a lumen (FIG. 4a). The distal portion 110 includes an electrode 103 and a distal surface 104 that defines an opening (further described below in this specification). The embodiment is operable to direct fluid forward as represented by fluid streamline 140. The forward opening facilitates use of the device with a guide wire.

[0023] Some embodiments of the electrosurgical device 120 include an insulating material 105 that covers a portion of the shaft of the elongate member 102 and / or the distal surface 104 of the device. It will be understood by those skilled in the art that the insulating material is an effective insulating material and may be a 100% insulating material or a partial insulating material. When a partial insulating material layer is located on the distal surface 104, the partial insulating material functions as an effective insulating material when using the device by allowing only limited electrical energy to flow through the partial insulating material, such that the electrical energy is insufficient to heat adjacent tissue and create a cavity within the tissue while advancing and passing the electrosurgical device.

[0024] Generally, in the present disclosure, the term "distal face" is used to refer to the end surface of the electrosurgical device as viewed from the distal end (rather than the internal or side surfaces) with reference to the entire electrosurgical device. The term "distal surface" is used to refer to the end surface of a particular portion of the device as viewed from the distal end of that portion. In some embodiments, the distal surface of the elongate member 102 and the distal face 104 refer to the same surface, such as in the embodiment of FIG. 3a for example.

[0025] Various embodiments of the present disclosure include an electrosurgical device 120 for puncturing tissue, the electrosurgical device 120 including an elongate member 102 defining a lumen 109 for receiving fluid; a distal face 104 of the electrosurgical device defining at least one opening 107, the distal face 104 including at least one cut portion 103a and at least one non-cut portion 105a, the at least one cut portion 103a and the at least one non-cut portion 105a cooperating to provide an elongate cut in the tissue when electrical energy is delivered to the distal face 104 while preventing coaring of the tissue. Some embodiments have only one distal opening, while other embodiments have two or more openings. In some examples, the device can be described as having an opening that is divided into two or more portions.

[0026] Various embodiments of the present disclosure further include at least one cut portion 103a configured to provide a first partial puncture upon energy delivery, the first partial puncture substantially corresponding to the at least one cut portion. The "first partial puncture" is the puncture provided by energy delivery prior to expanding or laterally displacing the tissue when advancing the electrosurgical device after energy delivery. The first partial puncture is fairly small and the device cannot be received without expanding or laterally displacing the tissue. As described above, the distal face 104 is configured to advance while preventing coaring of the tissue as the elongate member 102 is advanced. The first puncture is expanded by the distal face 104 of the electrosurgical device 120 when advancing the device. When the shaft of the elongate member is tapered, typically there is further expansion by the shaft during advancement.

[0027] In some embodiments, the elongate member 102 has a length ranging from about 30 cm to about 100 cm to facilitate puncture of the heart septum. In some embodiments, the elongate member has an outer diameter ranging from about 0.40 mm to about 1.5 mm and, for example, minimizes hemodynamic instability upon puncture, such as by ensuring that the hemodynamics are not destabilized by the puncture after removal of the electrosurgical device 120. In some embodiments, the electrosurgical device 120 is a rigid, elongate needle.

[0028] Some embodiments of the electrosurgical device 120 have a bending stiffness of at least about 0.016 Nm 2 such as about 0.017 Nm 2 and include an elongate member 102 having a bending stiffness that provides a palpable response to the user of the device.

[0029] Some embodiments of the device have markers that highlight important locations on the electrosurgical device 120. Such markers can include the location where the elongate member 102 begins to curve, the location of the electrode 103, or the location of the proximal edge of the angled distal face. In some embodiments, the markers are radiopaque. The image markers can be of different shapes including, but not limited to, ring-shaped hollow bands or coils. Alternative embodiments include disk-shaped, rectangular, and elongate image markers that define other geometric shapes or symbols.

[0030] The elongate member 102, which can be composed of one or more layers / components of plastic, other polymers, metal, or other materials, can have markers embedded within the sidewalls of the elongate member 102, which sidewalls may all be metal or substantially (mostly) metal. For example, the sidewalls that receive the markers can be covered with a relatively thin layer of polymer, such as a sidewall covered with an insulating layer. Since all metals are to some extent radiopaque, the radiopaque marker should be more opaque than the metal that makes up the elongate member in order to function properly. Generally, for any embodiment of a device having a radiopaque marker, the radiopaque marker can be composed of a material that is more opaque than any of the materials that make up the elongate member 102.

[0031] The embodiment of FIG. 1 is an elongate member 102 that is entirely straight, while in an alternative embodiment, the elongate member includes a curved section. In some examples, the curved section has a curved length of from about 10 to about 25 cm and spans from about 20° to about 40° of a circle. In some other examples, the curved section has a curved length of from about 4 to about 7 cm and spans from about 70 to about 110 degrees of a circle.

[0032] Typically, the handle 101 includes a connector that receives an electrical plug or other electrical connector and a fluid port that receives a second connector, such as a luer lock. Electrical energy can be delivered from an energy source through the connector located within the handle 101 and typically through a wire (not shown). The electrical energy is then transmitted to the elongate member 102 and the electrode 103.

[0033] Some embodiments of the handle 101 include a relatively large grippable surface having a ridge, for example to more efficiently transmit a tactile response that can be sensed by the transmission of vibration.

[0034] In some embodiments, one end of the tube is operably coupled to a fluid source (not shown), such as a syringe, pump, intravenous fluid bag, etc., and the other end of the tube is operably coupled to a connector to the fluid port of the handle 101. The fluid port is in fluid communication with the lumen 109 of the elongate member 102 via a conduit (not shown) of the handle, whereby the tube and the lumen 109 are in fluid communication with each other, thus enabling fluid to flow between the external device and the lumen 109.

[0035] In some embodiments, the opening 107 and the lumen 109 (e.g., FIG. 8) together realize a pressure transmission lumen coupled to an external tube by a connector, and the tube is in fluid communication with a pressure sensing device, such as a pressure transducer.

[0036] Figures 2a through 2c show a distal portion of one embodiment of the electrosurgical device 120, and the elongate member 102 is a conductive tubular member. The elongate member 102 defines a lumen 109 for receiving fluid. The fluid within the lumen (FIG. 2b) can be injected, withdrawn, or left substantially stationary. In some embodiments, the conductive tubular member is composed of stainless steel.

[0037] The conductive tubular member is at least partially covered by an insulating material 105, and the distal portion of the conductive tubular member is not covered (i.e., electrically exposed) to define the electrode 103. The non-cut portion 105a of the distal surface is provided with an insulating layer. In some embodiments (e.g., FIGS. 2a through c), the insulating layer is the same as the insulating material 105 that covers the shaft of the tubular member. The tubular member includes both the insulating material 105 that covers the shaft of the tubular member extending across the distal surface 104 and the insulating material that covers the distal surface 104, and these are the same type of individually applied materials. In an alternative embodiment, the insulating layer covering the distal surface 104 is a different type of insulating material.

[0038] The distal surface 104 of the electrosurgical device defines an opening 107 that communicates with the lumen 109. Referring to FIG. 2b, the insulating layer (non-cut portion 105a) has the shape of a segment of a circle, whereby the conductive tubular member (cut portion 103a in FIG. 2b) and the insulating layer define the opening 107.

[0039] In the embodiment of FIGS. 2a through c, the distal surface 104 is inclined and is composed of an electrically exposed conductive cut portion 103a and an insulating non-cut portion 105a. The distal surface of the electrode 103 forms the cut portion 103a, which in this embodiment is generally C-shaped or arcuate when viewing the distal surface 104 from the distal end. The cut portion 103a is elongated, i.e., non-circular, and has a length greater than its width. Further, the cut portion 103a does not completely surround or enclose or encircle the opening 107, but rather partially surrounds the opening.

[0040] The proximal portion 143 (FIG. 2c) of the distal surface 104 is composed of the non-cut portion 105a. The insulating portion 105a extends from the peripheral edge 145 of the distal surface 104 and partially covers the end surface of the tubular member. In some embodiments, the non-cut portion 105a is composed of a polymeric insulating material, which may be a heat-shrinkable material, a spray-painted material, or a material selectively coated by vapor deposition. In some alternative embodiments, the non-cut portion 105a comprises a ceramic. In some embodiments, the distal surface of the conductive tubular member has a stepped recess for receiving the insulating layer therein, thereby providing a flat distal surface 104 (i.e., making it so there is no stepped surface).

[0041] When advancing the electrosurgical device into the tissue, the cutting portion 103a is configured such that the energy delivered by the electrically exposed cutting portion 103a pierces the tissue without substantially occluding the lumen 109. Specifically, the cutting portion 103a is the leading surface of the electrode 103, and the leading surface defines a cutting surface (i.e., the cutting portion 103a) of the electrode that actually cuts through the tissue when delivering energy while advancing the energy delivery device. The outer peripheral portion of the distal surface of the electrode 103 defines (not all of) a portion of the periphery of the distal surface 104 (FIG. 2a), whereby the device provides a puncture portion corresponding to (not all of) a portion of the periphery of the distal surface 104. For this reason, the puncture portion defines a flap of tissue, and when advancing the device, the inclined distal surface laterally displaces this flap.

[0042] The embodiment of the electrosurgical device 120 of FIG. 2c includes a substantially rounded or atraumatic distal tip 146. This is because the device does not need to have a sharp tip on the device for puncturing. The rounded tip reduces the risk of accidentally puncturing the tissue and abandoning the support of the dilator. In other words, the distal portion 142 of the distal surface is substantially rounded. In some alternative embodiments, the tip of the device is sharp. Further, the flat surface of the distal surface 104 is substantially atraumatic.

[0043] In the embodiments of FIGS. 2a - c, the distal surface is inclined, while in some alternative embodiments, the distal surface comprises a flat tip. In such embodiments, the configuration of the distal surface enables the electrosurgical device 120 to operate to electrically puncture and laterally displace the tissue without creating a coaling when advancing the device.

[0044] Figures 3a-d illustrate an embodiment of an electrosurgical device 120, where the conductive material forms a cutting portion 103a and the non-cutting portion 105a comprises an insulating coating 106 on the distal surface of the device. In each of Figures 3a-d, the distal surface of the elongate member 102 includes one cutting portion 103a and one non-cutting portion 105a. Alternative embodiments include two or more cutting portions 103a and / or two or more non-cutting portions 105a. In some embodiments, the insulating coating 106 comprises a non-polymer layer of a material selected from the group including oxides, nitrides, and ceramics. More specific examples include layers of materials such as metal oxides, silicon oxides, silicon dioxide, or diamond thin films. In other embodiments, the insulating coating 106 can be any solid-state insulator.

[0045] In some embodiments, the elongate member 102 comprises a conductive tubular member (e.g., stainless steel), at least one non-cutting portion 105a comprises an insulator disposed along a portion of the distal surface of the elongate member 102, and further, the electrically exposed portion of the distal surface of the elongate member 102 forms at least one cutting portion 103a. Such embodiments can be made by a layer of insulating oxide deposited on the conductive metal tube by a method including (but not limited to) evaporation, chemical vapor deposition, or sputtering. This layer can be deposited only on the distal surface of the tube or on the sides of the tube. One or more portions of the insulating coating 106 are removed by a method including (but not limited to) laser ablation, chemical etching, or plasma etching to form at least one cutting portion 103a. Alternatively, during the deposition process, masking is used to cover at least one cutting portion 103a, and after deposition, the masking is removed to expose the electrode while the remainder of the distal surface is covered with an insulator to form at least one non-cutting portion 105a.

[0046] Figures 3a and 3b are a side perspective view and a front perspective view, respectively, of the electrosurgical device 120, and the distal surface 104 has an inclined surface. The non-cutting portion 105a (on the shaft of the elongate member 102) and the insulating material 105 are both composed of an insulating coating 106. The cutting portion 103a is composed of the distal surface of the electrode 103. In the embodiment of FIG. 3c, the distal portion of the insulating material 105 on the shaft of the elongate member 102 is composed of the insulating coating 106 (described above), and the proximal portion is composed of a polymer 105b. In the embodiment of FIG. 3d, the distal surface 104 of the device has a substantially flat tip.

[0047] In some alternative embodiments, at least one cutting portion is located on the distal surface 104 along the inner surface of the elongate member 102, i.e., the cutting portion 103a is an adjacent opening 107 while not extending to the outer periphery of the distal surface 104.

[0048] The non-polymer coatings (such as ceramics, oxides, and diamond thin films) described above can function as effective insulators in a thinner layer state than typical polymers. In some examples of the electrosurgical device 120, the insulating coating comprises a layer having a thickness of less than about 1 micron. In some specific examples, the insulating coating comprises a layer having a thickness from about 100 nanometers to about 1 micron. In some other examples, the insulating coating comprises a layer having a thickness from about 1 micron to about 50 microns. In some specific examples, the insulating coating comprises a layer having a thickness from about 1 micron to about 25 microns, and in some more specific examples, the insulating coating comprises a layer having a thickness from about 1 micron to about 10 microns.

[0049] In some alternative embodiments where at least one cutting portion comprises a conductive material, at least one non-cutting portion of the distal surface is composed of a partial insulating layer. When sufficient tissue heating occurs such that electricity flows through the electrodes to electrically puncture (i.e., without a pushing force) the tissue and is applied to the effective partial insulating layer on the distal surface 104 of the device, it results in some current flowing through the partial insulating layer, but this current is insufficient to heat the tissue and create a cavity within the tissue while advancing the electrosurgical device through.

[0050] Figures 4a - g are for an electrosurgical device 120 that punctures tissue. The device 120 includes an elongate member 102 that defines a lumen 109 (Figure 4a) for receiving fluid. The distal surface of the elongate member 102 defines an opening 107 and a conductive portion (the distal surface of electrode 103) that at least partially surrounds the opening. The conductive portion defines a biased electrode 103 that is configured to create a non-coaxial cutting portion within the tissue when energy is delivered to the distal surface. The distal surface includes a non-cutting portion 105a and a cutting portion 103a, as described below. Further, the distal surface of the elongate member 102 is configured to advance while preventing coaxialization during advancement of the elongate member.

[0051] Figures 4a - d show embodiments having a conductive elongate member 102 that has an insulating material layer 105 covering the shaft of the elongate member. In the example of Figure 4c, the distal surface of the elongate member 102 is shown by the electrode 103 (which is also the conductive portion), and the distal surface 104 of the electrosurgical device 120 includes the insulating material 105. The embodiment of Figure 4e includes the distal surface 104, and the insulating material 105 extends across a portion of the electrode 103.

[0052] In a typical embodiment where the opening is eccentric, the conductive portion (electrode 103) defines an outer peripheral portion, the narrow region of the conductive portion includes a part of the outer peripheral portion closest to the opening (for example, the bottom of the electrode 103 in FIG. 4c), and the wide region of the conductive portion includes a part of the outer peripheral portion farthest from the opening (for example, the upper part of the electrode 103 in FIG. 4c), thereby defining a narrow conductive region and a wide conductive region respectively.

[0053] When power is supplied to the distal surface of the conductive portion, the voltage is the same in the narrow conductive region and the wide conductive region, while the intensity of the electric field and the current are more concentrated when passing through the narrow conductive region and entering the adjacent tissue than when passing through the wide conductive region. Thereby, the tissue adjacent to the narrow conductive region is heated to a higher temperature than the tissue adjacent to the wide conductive region. As an example, in some cases, the tissue adjacent to the wide conductive region is heated to 50 degrees Celsius without electrically perforating the tissue, while the tissue adjacent to at least a part of the narrow conductive region is heated to 300 degrees Celsius for electrically perforating the tissue. Therefore, when the conductive portion is configured such that more current is concentrated in the narrow conductive region than in the wide conductive region, a biased electrode is defined, the narrow conductive region includes at least a part of the cut portion 103a, and the wide conductive region includes at least a part of the non-cut portion 105a.

[0054] Some alternative embodiments include an elongate member 102 that is substantially composed of a non-conductive material. In the examples of FIGS. 4f and 4g, the electrosurgical device 120 includes an elongate member formed from an insulating material 105 (typically a polymer) and a wire 111 operable to supply electricity to the electrode 103. The electrode 103 has an overall plate form and is composed of a conductive material, such as metal. The electrode 103 has no sharp corners or edges so as not to generate hot spots due to interruptions. In the embodiments of FIGS. 4f and 4g, the electrode 103 covers the end surface of the insulating material 105 such that the distal surface of the electrode 103 forms the distal face 104 of the electrosurgical device 120. Some embodiments include at least a portion of a narrow conductive region that is arcuate in shape. In the example of FIG. 4g, a portion of the narrow conductive region that is arcuate in shape includes a portion having a substantially constant radial width or thickness.

[0055] The embodiment of FIG. 4d has an inclined distal face 104, while the embodiments of FIGS. 4a and 4f each have a distal face 104 with a tip having a substantially flat surface.

[0056] Figures 5a through 5c illustrate another embodiment of the electrosurgical device 120, where the elongate member 120 comprises a conductive tubular member 112 that is at least partially covered by an insulating material 105. The conductive tubular member 112 has a notch portion proximal to the distal face 104 (of the electrosurgical device 120), and the electrosurgical device 120 further comprises an insulating insert 144 positioned in the notch portion. The distal face 104 of the electrosurgical device comprises the distal surface of the conductive tubular member that defines at least one cutting portion 103a, and at least a portion of the distal surface of the insulating insert 144 that defines at least one non-cutting portion 105a. The distal face 104 of the electrosurgical device 120 is inclined. In some alternative embodiments, the distal face 104 defines a flat tip. Typically, the insulating insert 144 is a polymer. In some embodiments, the insulating insert 144 is a rigid plastic, and in some particular embodiments, it is reflow FEP (fluorinated ethylene propylene). Figure 5c, which is a rotated side view, shows the device having a partially notched insulating material 105 and shows how the insulating insert 144 of the conductive tubular member 112 is received.

[0057] Figure 5b is a cutaway side view showing the electrode 103 extending from the conductive tubular member 112. The side views of Figures 5a and 5b show that the electrode 103 is an electrically exposed portion of the tubular member 112 (i.e., the electrode is continuous with the conductive tubular member 112) and is not covered by the insulating material 105.

[0058] The end view of Figure 5a shows the insulating insert 144 positioned between the layer of insulating material 105 and the electrode 103. Figures 5b and 5c show how the insulating insert 144 fits into the notch portion of the conductive tubular member 112 and show that the insulating material 105 surrounds both the conductive insert 44 and the conductive tubular member 112.

[0059] As shown in the end view of FIG. 5a, the insulating portion 105a of the distal surface 104 is composed of the end surfaces of both the insulating material 105 and the insulating insert 144. The electrically exposed conductive portion 103a is composed of the distal surface of the electrode 103. The end view of FIG. 5 shows that the electrically exposed conductive portion 103a has the shape of a segment of a circle, and the insulating portion 105a extends radially from the opening 107 to the peripheral edge 145 of the distal surface 104. The insulating insert 144 defines the opening 107. The electrically exposed conductive portion 103a is not completely or partially surrounding the opening 107, but is lateral to the opening 107, and thus does not form a ring-shaped electrode that can core tissue and make a hole.

[0060] FIGS. 6a and 6b show an embodiment of the electrosurgical device 120, where the distal end of the elongate member 102 is asymmetrically cut at the tip, defining a stepped distal surface 104 (of the electrosurgical device 120), and this stepped distal surface 104 has a leading portion 104a and a recessed portion 104b. The leading portion 104a includes the cut portion 103a, and the recessed portion 104b includes the non-cut portion 105a. In the example of FIGS. 6a and 6b, the leading portion 104a is arcuate in shape. Typically, the elongate member 102 comprises a conductive tubular member at least partially covered by an insulating material 105. In some embodiments, the non-cut portion 105a comprises an insulating polymer layer.

[0061] In the embodiment of FIG. 6a, the recessed portion 104b defines a substantially flat surface with the non-cut portion 105a, and the leading portion 104a defines a flat tip.

[0062] In the embodiment of FIG. 6b, the leading portion 104a defines an inclined corner 147, and the recessed portion 104b defines a sloped surface that at least partially defines at least one non-cut portion.

[0063] In some alternative embodiments (not shown), the leading portion 104a is inclined.

[0064] Figures 7a through 7c illustrate an example of an electrosurgical device 120, where at least one cutting portion 103a is substantially arcuate and is positioned along the inner surface of the elongate member 102. Typically, at least one cutting portion 103a comprises a conductive material and at least one non-cutting portion 105 comprises an insulating layer and is disposed along the distal surface of the elongate member.

[0065] In the embodiment of FIG. 7b, the cutting portion 103a is crescent-shaped. FIG. 7c shows an embodiment where the distal surface 104 is inclined. All of the examples of FIG. 7 have a forward-facing opening 107.

[0066] Some alternative embodiments (not shown) include a cutting portion 103a embedded within the wall of the elongate member 102.

[0067] Some other alternative embodiments (not shown) include an elongate member 102 that comprises a conductive tubular member at least partially covered by an insulator 105, where at least one non-cutting portion 105a comprises an insulator disposed along a portion of the distal surface of the elongate member 102, and the electrically exposed portion of the distal surface of the elongate member 102 forms at least one cutting portion 103a that is positioned along the inner surface of the elongate member 102 to the distal surface 104, i.e., the cutting portion 103a is adjacent to the opening 107 on one side and does not extend to the outer peripheral portion of the distal surface 104.

[0068] In some other alternative embodiments, the elongate member 102 is composed of a non-conductive material (e.g., a polymer) and a conductive wire that extends to an electrode to supply power to the electrode, and at least one cutting portion 103a is an electrode that is substantially arcuate and is positioned along the inner surface of the elongate member 102.

[0069] The embodiment of FIG. 8 is for an electrosurgical device 120, which comprises an elongate member 102 made of a non-conductive material and defining a lumen 109 for receiving fluid; a distal surface 104 defining an opening, the distal surface 104 including at least one cutting portion 103a and at least one non-cutting portion 105a, the at least one cutting portion 103a and the at least one non-cutting portion 105a cooperating to deliver electrical energy to the distal surface 104 to result in an elongate cut in the tissue while being configured to prevent coreling of the tissue. The distal end surface of the elongate member 102 defines an opening 107. Typically, the elongate member 102 is composed of a polymer. In the embodiment of FIG. 8, the distal end surface of the electrode 103 is located at the distal end of the elongate member 102 and includes at least one cutting portion 103a. The illustrated embodiment has an inclined distal surface 104. In some embodiments, the distal end surface of the electrode 103 is crescent-shaped, while in some other embodiments, the distal end surface has the shape of a segment of a circle.

[0070] In the embodiment of FIG. 8, the wire 111 is embedded within the sidewall of the elongate member 102 and is connected to the electrode 103 to deliver energy to the electrode 103. In some alternative embodiments, the wire 111 is housed within a lumen of appropriate size.

[0071] In the illustrated embodiment, the non-cutting portion 105a is located at the proximal portion of the distal surface 104 and is composed of the distal surface of the elongate member 102. Typically, the non-cutting portion 105a is composed of a polymer. When viewed from the end, the non-cutting portion 105a surrounds the opening 107, while the cutting portion 103a does not surround the opening 107 and is lateral to the opening 107, thus not forming a ring-shaped electrode that can core the tissue.

[0072] The related embodiments of FIGS. 9 and 10 are for an electrosurgical device 120, which includes a protruding electrode 103 that defines a tip surface 104c (FIGS. 9a and 10b) distal to the elongate member 102, and the tip surface 104c includes at least one cut portion 103a. The distal surface 104 includes a subsequent surface 104d (FIGS. 9a and 10b) defined by the distal end surface of the elongate member 102. The subsequent surface 104d includes an insulating material 105 that forms a non-cut portion 105a. In some embodiments, the tip surface 104c is substantially flat. In some examples, the protruding electrode 103 is connected to a rotation mechanism so that the tip surface 104c can rotate during energy delivery. The distal surface 104 of the electrosurgical device includes the tip surface 104c and the subsequent surface 104d.

[0073] In the embodiments of FIGS. 9a and b, the protruding electrode 103 substantially bisects the opening 107 into two portions. The protruding electrode 103 is, in practice, rectangular in shape when viewed from the end. In some examples, the tip surface 104c is substantially rectangular in shape.

[0074] Some embodiments of the electrosurgical device 120 include a protruding electrode 103 that includes at least three elongate portions that radiate from a central point 103b. Some such devices include a protruding electrode 103 that substantially divides the opening 107 into at least three pie-slice shaped wedges. Some embodiments include a protruding electrode 103 that defines the tip surface 104c as having at least three elongate portions that radiate from a central point 103b. The example of FIG. 10 has six elongate portions of the electrode 103 that radiate from the central point 103b and divides the opening 107 into six wedge-shaped segments. Some embodiments further include at least three elongate portions of the tip surface 104c that are proximally tapered as they radiate from the central point 103b.

[0075] Some embodiments of FIGS. 9 and 10 include an elongate member 102, which comprises a conductive tubular member having an insulating material 105 that forms a non-cut portion 105a on the distal surface of the tubular member. Some alternative embodiments include an elongate member 102 comprising a non-conductive material, such as a polymer.

[0076] An embodiment of the electrosurgical device of FIG. 11 includes at least one cutting portion 103a that is in an arcuate shape and partially surrounds an opening 107, and the at least one cutting portion 103a comprises at least one active electrode 103 (shown by "A" in FIG. 11) and at least one return electrode 103 (shown by "R" in FIG. 11) that are operable to deliver energy bipolarly. Typically, embodiments have pairs of electrodes, one being an active electrode and one being a return electrode, and typical embodiments have 2, 4, 8, 10 or more electrodes.

[0077] In some embodiments, such as the example of FIG. 11, the cutting portion 103a comprises a 180-degree arc. The cutting portion 103a of FIG. 11 includes four active electrodes and four return electrodes arranged in an alternating pattern.

[0078] In a typical embodiment, the non-cut portion 105a comprises an insulating material 105.

[0079] The example shown in FIG. 12 is for another bipolar device. The electrosurgical device of FIG. 12 includes at least one cutting portion 103a, and the at least one cutting portion 103a comprises an active electrode 103 (shown by "A" in FIG. 12) and a return electrode 103 (shown by "B" in FIG. 12) that are parallel to each other and extend substantially across the opening 107, and the active electrode and the return electrode are operable to deliver energy bipolarly. In a typical embodiment, the opening 107 is between the active electrode and the return electrode as shown.

[0080] In some embodiments, both the portion of the distal surface 104 between the active electrode and the elongate member 102 and the portion of the distal surface between the return electrode and the elongate member 102 are composed of the insulating material 105. In the embodiment of FIG. 12, the above-described insulating material 105 between the electrode and the elongate member 102 and the insulating material 105 on the distal surface together form an uninterrupted portion 105a. The distal surface 104 of the electrosurgical device includes the above-described cut portion 103a and the uninterrupted portion 105a.

[0081] FIGS. 13a and 13b illustrate one embodiment of a method of piercing tissue. The method includes (a) delivering energy to tissue 141 at a target site through the electrically exposed conductive portion 103a of the electrosurgical device 120, resulting in a puncture portion that substantially corresponds to the elongate cut portion of the distal surface of the electrosurgical device; and (b) expanding or widening the puncture portion without coring the tissue, primarily by advancing the flat or angled distal surface of the electrosurgical device. In some embodiments, the step of delivering energy includes causing a flap in the tissue, and the step of expanding or widening is completed without further energy delivery. In some embodiments, the target site is tissue within the heart, and in some particular embodiments, the tissue is the atrial septum 132. Typically, the method uses an outer cannula, such as the outer cannula 130 of FIG. 7a. The term "expand" is used herein to mean "make wider, make larger, or open wider".

[0082] An alternative embodiment of the tissue piercing method includes (a) delivering energy to the tissue at the target site through the cut portion of the distal surface of the electrosurgical device, resulting in an elongate puncture in the tissue while preventing energy delivery from the non-cut portion of the distal surface; and (b) advancing the electrosurgical device through the tissue by laterally displacing the flap of tissue defined by the puncture. The energy delivery step includes causing one or more incisions in the tissue (using the embodiment of FIG. 10).

[0083] Expansion of the piercing portion typically involves displacing tissue. In some embodiments, expansion involves cutting into and separating a surrounding portion of the tissue, thereby compressing the surrounding portion outwardly.

[0084] Some embodiments of the method include the use of a medical imaging modality to guide the electrosurgical device 120 to the target site. Some embodiments include measuring pressure to position the electrosurgical device 120 at the target site. In some embodiments, the method includes the use of a radiopaque marker 160 to position the electrosurgical device 120. Some embodiments include advancing the electrosurgical device to the target site over a guide wire.

[0085] In some embodiments, the method includes advancing the electrosurgical device 120 to the target site through the dilator 128; positioning the electrosurgical device 120 such that the cutting portion 103a is aligned with or slightly protrudes from the distal end of the dilator 128; and delivering fluid through the opening 107 (e.g., FIG. 3) at the distal end of the electrosurgical device 120 to stain the tissue. The fluid is typically delivered longitudinally forward through the electrosurgical device. Some embodiments further include the step of withdrawing fluid through the open distal face of the electrosurgical device.

[0086] In some embodiments, the distal surface of the electrically exposed conductive portion 103a is generally C-shaped, and step (b) includes providing a generally C-shaped piercing portion. In some other embodiments, the distal surface of the electrically exposed conductive portion is generally crescent-shaped, and step (b) includes providing a generally crescent-shaped piercing portion. In still other embodiments, the distal surface of the electrically exposed conductive portion is generally arcuate-shaped, and step (b) includes providing a generally arcuate-shaped piercing portion.

[0087] In some embodiments of the broad aspect, both the aperture 107 and the lumen 109 comprise a pressure transmission lumen, and the method further includes measuring the fluid pressure of the pressure transmission lumen using a pressure sensing mechanism.

[0088] In an RF piercing or puncturing procedure, unlike RF ablation, energy is applied to rapidly increase the tissue temperature to the extent that intracellular fluid is converted to vapor, which includes cell lysis due to increased pressure within the cell. When cell lysis and rupture occur, a cavity is created, allowing the tip of the catheter to penetrate the tissue. To achieve this effect, the RF piercing device must apply a high voltage to the tissue region for a short period of time. Also, the tip of the device used should be relatively small in order to increase the impedance of the device. This is in contrast to RF ablation, which uses a device with a larger tip to deliver a low impedance and high power signal to the area involved. Further, in contrast to RF piercing, which creates a cavity within the tissue through which the device can advance, the purpose of RF ablation is to create a large non-penetrating lesion within the tissue to disrupt electrical conduction. Thus, for the purposes of the present invention, piercing is defined as creating a cavity within a substance.

[0089] Embodiments of the present invention are operable to effect such a puncture or cavity without substantially removing a plug or core of material from the tissue at the target site. This is because, as described above herein, the punctures obtained from the device are typically in a C-shaped or similar configuration, such as a cut, which substantially corresponds to the shape(s) of the cutting portion(s) of the distal face of the electrosurgical device.

[0090] The electrosurgical device 120 can be used with a radiofrequency energy source suitable for piercing substances within a patient's body. The energy source can be a radiofrequency (RF) generator, which is operable in the range from about 100 kHz to about 1000 kHz and is designed to generate a high voltage in a short period of time. More specifically, in some embodiments, the voltage generated by the generator increases from about 0 V (peak-to-peak) to exceed about 75 V (peak-to-peak) in less than about 0.6 seconds. The maximum voltage generated by the generator can be between about 180 V peak-to-peak and about 3000 V peak-to-peak. The waveforms generated can be various, and can include, among others, for example, sine waves, rectangular waves or pulse rectangular waves. During the delivery of radiofrequency energy, for example, due to damage to the tissue near the target site or the formation of a water vapor layer after cell rupture, the impedance load of the generator may increase. The generator is operable to continue increasing the voltage even when the impedance load increases. For example, the energy can be delivered to the body tissue at a voltage that rapidly increases from about 0 V (RMS) to about 220 V (RMS) over a period between about 0.5 seconds and about 5 seconds.

[0091] While not limited to a particular theory of operation, in certain situations such as those described hereinabove, dielectric breakdown and arcing may occur upon delivery of radio frequency energy, which may thereby cause polar molecules to be separated. The combination of these factors may result in the formation of an insulating water vapor layer around the electrodes, resulting in an increase in impedance, for example, the impedance may increase up to and exceeding 4000 Ω. In some embodiments, despite this high impedance, the voltage continues to increase. A further increase in voltage may be desirable to increase the intensity of the RF treatment and to enable an increase in the perforation rate and the generation of punctures. An example of a suitable generator for this application is the BMC RF Perforation Generator (model number RFP-100A, Baylis Medical Company, Montreal, Canada). This generator delivers continuous RF energy at approximately 460 kHz.

[0092] When the generator operates in monopolar mode, the ground pad or dispersive electrode can be electrically coupled to the generator and brought into contact with or attached to the patient's body to provide a return path for the RF energy.

[0093] Further details regarding the devices and methods can be found in U.S. Application No. 13 / 468,939, filed May 10, 2012; U.S. Application No. 11 / 905,447, filed October 1, 2007 (now issued as U.S. Patent No. 8,192,425); U.S. Application No. 13 / 113,326, filed May 23, 2007; U.S. Application No. 11 / 265,304, filed November 3, 2005 (now U.S. Patent No. 7,947,040); U.S. Application No. 10 / 666,301, filed September 19, 2003 (now issued as U.S. Patent No. 7,048,733); U.S. Application No. 10 / 760,479, filed January 21, 2004 (now issued as U.S. Patent No. 7,270,662); U.S. Application No. 10 / 666,288, filed September 19, 2003; U.S. Application No. 10 / 347,366, filed January 21, 2003 (now issued as U.S. Patent No. 7,112,197); U.S. Provisional Application No. 60 / 522,753, filed November 3, 2004; and Provisional Application No. 60 / 884,285, filed January 10, 2007; No. 60 / 827,452, filed September 29, 2006; and No. 61 / 653967, filed May 31, 2012; No. 61 / 681,512, filed August 9, 2012. The entire contents of all applications and patents named above are hereby incorporated by reference into this specification in their entirety.

[0094] Thus, as described hereinabove, the problem of delivering fluid forward while piercing tissue without causing core formation is solved by an electrosurgical device having a distal face defining at least one opening, the distal face including at least one cutting portion and at least one non-cutting portion, the at least one cutting portion and the at least one non-cutting portion cooperating to provide an elongated cut in the tissue when electrical energy is delivered to the distal face while preventing core formation of the tissue.

[0095] Example 1: An embodiment having the configuration of FIG. 2 was tested and it was found that the tissue was punctured without substantially any coring occurring. Also, a charged broken blow needle was tested and it was found that the tissue was cored during puncture. The tests revealed that the embodiment of FIG. 2, when viewed from the side, cuts a C-shaped puncture portion corresponding to the shape of the electrode, resulting in a skin flap, and this flap is laterally displaced by the proximal portion of the distal face 104 when the electrosurgical device 120 is advanced, thereby expanding the C-shaped puncture portion.

[0096] The above-described embodiments of the present invention are for illustrative purposes only. Accordingly, it is intended that the scope of the present invention be limited only by the appended claims.

[0097] It will be appreciated that the specific features of the invention described in the context of individual embodiments for clarity may also be provided in combination within a single embodiment. Conversely, the various specific features of the invention described in the context of a single embodiment for brevity may also be provided individually or in any suitable partial combination.

[0098] Although the invention has been described with respect to specific embodiments, it is obvious that many alternative, modification, and variation forms will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternative, modification, and variation forms that fall within the broad scope of the appended claims. All publications, patents, and patent applications mentioned in this specification are hereby incorporated by reference in their entirety to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. Further, any citation or identification of a reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention.

Claims

**Claim 1** An electrosurgical device for puncturing tissue, comprising an elongated member having a conductive tubular member defining a lumen for receiving fluid, the elongated member having a distal end including a stepped distal surface, the stepped distal surface including an arcuate leading portion and a recessed portion defining an opening, and the elongated member. The arcuate leading portion of the stepped distal surface includes an elongated cutting portion including an electrode protruding in the distal direction, and the recessed portion of the stepped distal surface includes a non-cutting portion including an insulating material. The elongated cutting portion partially surrounds the opening and defines a flat tip, an electrosurgical device. **Claim 2** **Claim 3** The conductive tubular member has a bending stiffness of at least 0.016 Nm in order to enable tactile feedback to the user of the electrosurgical device. ２ The electrosurgical device according to claim 1, having such bending stiffness. The elongated member includes a shaft covered with a first insulating material, and the insulating material includes a second insulating material different from the first insulating material. The electrosurgical device according to claim 1. **Claim 4** The second insulating material is made of a polymer insulating material. The electrosurgical device according to claim 3. **Claim 5** The polymer insulating material is a heat-shrinkable material. The electrosurgical device according to claim 4. **Claim 6** The polymer insulating material is a spray coating material. The electrosurgical device according to claim 4. **Claim 7** The polymer insulating material is a ceramic. The electrosurgical device according to claim 4. **Claim 8** The stepped distal surface has a stepped recess for receiving an insulating layer therein. The electrosurgical device according to any one of claims 3 to 7. **Claim 9** The second insulating material is made of a non-polymer layer. The electrosurgical device according to claim 3. **Claim 10** The non-polymer layer is a material selected from the group consisting of oxides, nitrides, and ceramics. The electrosurgical device according to claim 9. **Claim 11** The non-polymer layer is selected from the group consisting of metal oxides, silicon oxides, and silicon dioxide. The electrosurgical device according to claim 9. **Claim 12** The non-polymer layer is a diamond thin film. The electrosurgical device according to claim 9. **Claim 13** The non-polymer layer has a thickness of less than 1 micrometer. The electrosurgical device according to any one of claims 9 to 12. **Claim 14** The non-polymer layer has a thickness of 1 micrometer to 50 micrometers. The electrosurgical device according to any one of claims 9 to 12. **Claim 15** ​ The electrosurgical device according to any one of claims 9 to 12, wherein the non-polymer layer has a thickness of 1 micrometer to 25 micrometers.

16. The electrosurgical device according to any one of claims 9 to 12, wherein the non-polymer layer has a thickness of 1 micrometer to 10 micrometers.

Images