HK1112717A - Device and method for thermal ablation of biological tissue using spherical ablation patterns - Google Patents

Description

Biological tissue thermal ablation apparatus and method using spherical ablation patterns

Cross reference to related applications

This application claims priority from U.S. provisional patent application 60/644,722 filed on 18/1/2005.

Technical Field

The present invention relates generally to devices and methods for tissue ablation, and more particularly to devices for surrounding target biological tissue.

Background

Standard surgical procedures, such as tissue resection for the treatment of benign and malignant tumors of the liver and other organs, present some key disadvantages that affect efficacy, morbidity, and mortality. The basic problem with these disadvantages is that resection cannot be performed in many cases. To help overcome this limitation, a range of monopolar Radiofrequency (RF) devices are designed for tissue ablation and resection. However, these monopolar devices are of limited use in a typical clinical setting because they are overly complex and difficult to use, and result in a time-consuming procedure that may cause additional injury to the patient through grounding pad burns (grouping padburs). Moreover, these monopolar tissue ablation devices have limitations in the range and size of ablations that can be produced, and exhibit poor consistency of ablation results and overall inefficiencies. Commonly known ablation devices are designed to penetrate into the target tissue and ablate the tissue from the inside out. This approach can result in uneven heating of the target tissue and can result in tumor seeding due to repeated punctures and retractions from the malignant tissue (tumor seeding). Accordingly, there is a need for a tissue ablation system that overcomes the disadvantages of these single-pole tissue ablation devices.

Drawings

Fig. 1 is a tissue ablation device according to one embodiment including a handpiece, a deployment sled, a delivery member/tube, and a plurality of energy conduits in a stowed state and connected between an energy source and a distal tip.

Fig. 2 is a tissue ablation device according to the embodiment of fig. 1, including a handpiece, a deployment sled, a delivery member/tube, and a plurality of energy conduits in a deployed state and connected between an energy source and a distal tip.

Fig. 3 is a distal portion of a tissue ablation device according to the embodiment of fig. 1, including a delivery member/tube and a plurality of energy conduits in a stowed state.

Fig. 4 is a distal portion of a tissue ablation device including a delivery member/tube and a plurality of energy conduits in a deployed state, according to the embodiment of fig. 1.

Fig. 5 shows an enlarged view of a distal portion of a tissue ablation device including a central deployment rod and a plurality of energy conduits in a deployed state, according to the embodiment of fig. 1.

Fig. 6 shows an enlarged view of an intermediate section of a tissue ablation device including a central deployment rod and a plurality of energy conduits in a deployed state, according to the embodiment of fig. 1.

Fig. 7 shows an exploded view of the distal end of a tissue ablation device according to the embodiment of fig. 1, including a central deployment rod, a rotated side view of a delivery member/tube including a plurality of energy conduits and deployment rod, and a distal tip.

Figure 8 is an end view of a plurality of deployed energy conduits having diameters of 5, 6, and 7 centimeters (cm) according to the embodiment of figure 1.

Fig. 9 is a cross-sectional view of an energy conduits configured to at least one of cut, separate, and divide tissue when pressed or impacted against the tissue, according to an embodiment.

Fig. 10 is a distal portion of a tissue ablation device including a delivery member/tube and a plurality of energy conduits in a deployed state according to an alternative embodiment.

Fig. 11 is a distal portion of a tissue ablation device including a delivery member/tube and a plurality of energy conduits in a deployed state according to another alternative embodiment.

Fig. 12 is a flow diagram of a tissue ablation procedure using a tissue ablation device according to an embodiment.

Fig. 13 illustrates a helical electrode ablation device according to one embodiment.

Fig. 14 illustrates a combination electrode ablation device including a fluid path according to an embodiment.

Fig. 15A shows a two-stage ablation device for surrounding a target point, according to one embodiment.

Fig. 15B illustrates an end view of the ablation device of fig. 15A, according to one embodiment.

Fig. 15C illustrates an end view of the ablation device of fig. 15A according to an alternative embodiment.

Fig. 16A shows an ablation device including a surrounding electrode and a piercing electrode according to one embodiment.

Fig. 16B shows an ablation device including a surrounding electrode and a fluid delivery element according to one embodiment.

Fig. 17 illustrates an ablation device with electrodes extending through the side of the trocar according to one embodiment.

Fig. 18 is an ablation device with electrodes extending through the tip of a trocar according to one embodiment.

Fig. 19A is a side view of a trocar having a helical electrode extending from a trocar tip according to one embodiment.

Figure 19B is a top view of the embodiment shown in figure 19A showing the electrodes surrounding the target tissue.

Fig. 20 illustrates an ablation system with a combination helical electrode, according to one embodiment.

Fig. 21 shows a spiral electrolytic ablation device according to a second alternative embodiment.

Fig. 22 illustrates a combination ablation device including two independent trocars surrounding a target tissue, according to one embodiment.

Fig. 23A is a side view of a combination ablation device including two independent trocars surrounding a target tissue according to an alternative embodiment.

Fig. 23B is an end view of the alternative embodiment of fig. 23A.

Fig. 24A illustrates a multi-trocar system including two single element electrodes configured to at least partially surround a target tissue, according to one embodiment.

FIG. 24B shows an alternative embodiment of a multi-trocar system in which one electrode extends through the side of the trocar.

Fig. 25A shows a three cannula needle system configured to at least partially surround a target tissue according to one embodiment.

FIG. 25B is an end view of the three cannula needle system of FIG. 25A.

In the drawings, like reference numbers identify identical or substantially similar elements or acts. To facilitate discussion of any particular element or action, the most significant digit or digits in a reference number refer to the figure number in which that element is first introduced (e.g., element 108 is first introduced and discussed in FIG. 1).

Detailed Description

A tissue ablation system including a plurality of components and methods for surrounding a target tissue and producing a tissue ablation volume in various biological tissues is described herein. The biological tissue includes tissues of various organs of the human body including, but not limited to, the liver, spleen, kidney, lung, breast and other organs. In the following description, numerous specific details are introduced to provide a thorough understanding and enabling description for embodiments of the tissue ablation system. One skilled in the relevant art will recognize, however, that the tissue ablation system can be practiced without one or more of the specific details, or with other components and systems. In other instances, well-known structures or operations are not shown or described in detail to avoid obscuring aspects of the tissue ablation device.

Fig. 1 is a tissue ablation system 100 according to one embodiment. The tissue ablation system 100 includes a tissue ablation device 101 connected to at least one energy source 112. According to one embodiment, the tissue ablation device 101 includes a handpiece 102, a deployment sled 104, a delivery member/tube 106, a plurality of energy conduits 108, and a distal tip 110. The energy conduits 108 (also referred to herein as electrodes 108) are in a stowed state, but are not so limited. Fig. 2 is a tissue ablation device having an energy conduit 108 in a deployed state according to one embodiment. The tissue ablation device 101 may also include other components known in the art and suitable for procedures involving the tissue ablation device 101.

The components of the tissue ablation system 100 are described in sequence with respect to fig. 1 and 2. The handpiece 102 of the tissue ablation device 101 includes a handle for a user to hold the tissue ablation device 101. The handpiece 102 provides a connection between an energy source 112 and one or more energy conduits 108, and the energy conduits 108 may or may not be connected to at least one of the handpiece 102 and the energy source 112. The deployment sled 104 or advancement mechanism 104 (which in one embodiment is integrated into the handpiece 102) deploys or stows the energy conduits 108 when activated.

The tissue ablation device 101 also includes a delivery member/tube 106 that supports placement of an energy conduit 108 in the target tissue, but is not so limited. The material used to form the delivery member/tube 106 is at least one of electrically conductive, conditioned, and coated to allow electrical conduction through the electrode. For example, the material used to form the delivery member/tube 106 is at least one of stainless steel, nickel titanium, alloys, and plastics including Ultem, polycarbonate, and liquid crystal polymers, but is not limited thereto. The delivery member/tube 106 has a diameter of about 0.05-0.5 inches and a length of about 0.1-20 inches and is adapted to be stretched into an area of the body suitable for the treatment procedure. For example, the delivery member/tube 106 in one embodiment has a diameter of about 0.08 to 0.3 inches and a length of about 2 to 12 inches.

The energy conduits 108, which are configured for insertion into a particular tissue type, are formed of one or more materials that are shaped, sized, and patterned to support attachment to the target tissue and to allow the energy conduits 108 to deliver sufficient energy to ablate the target tissue. The energy conduits 108 comprise a material selected from, for example, conductive or plated metals and/or plastics, superalloys including shape memory alloys, and stainless steel. For example, the energy conduits 108 comprise a nickel titanium alloy, but may be formed from a variety of materials including stainless steel, nickel titanium, and various alloys, or any combination thereof.

The energy conduits 108 of an embodiment (which may be referred to collectively as the electrode array 108) may have a variety of different dimensions (including length and diameter) depending on the energy delivery parameters (current, impedance, etc.) of the corresponding system. The use of energy conduits 108 of different diameters allows balancing the energy/energy density in the target tissue. Thus, the use of energy conduits 108 of different diameters provides a way to control the energy balance of the target tissue in addition to the spacing between the energy conduits 108. The one or more energy conduits 108 in one embodiment have an outer diameter of about 0.005 to about 0.093 inches, but are not limited thereto. Furthermore, the length of the energy conduits 108 in one embodiment is sufficient to produce or manufacture an ablation diameter of about 1-15 centimeters, but is not so limited. For example, one embodiment of the energy conduits 108 has an outer diameter of about 0.01 to about 0.025 inches and a length sufficient to produce or produce an ablation diameter of about 3 to about 9 centimeters.

The energy conduits 108 in various alternative embodiments may include materials that support the bending and/or shaping of the energy conduits 108. Furthermore, the energy conduits 108 of alternative embodiments may include insulating materials, coatings, and/or coverings in multiple segments and/or portions along the axis of the energy conduits 108 that are tailored to the respective procedure and/or energy delivery requirements of the target tissue type.

The energy source 112 (also referred to as the generator 112 or generator 112) of one embodiment delivers a predetermined amount of energy at a selectable frequency to ablate tissue, but is not so limited. The energy source 112 includes at least one of a variety of energy sources including generators operating in the Radio Frequency (RF) range. More specifically, the energy source 112 includes an RF generator having an operating frequency of about 375 kHz to about 650 kHz, an operating current of about 0.1 Amp to about 5 Amp, and an operating impedance of about 5 ohms to about 100 ohms, but is not limited thereto. For example, one embodiment of the energy source 112 may operate at a frequency of about 400 kHz to about 550 kHz and at a current of about 0.5 amperes to about 4 amperes, but is not limited thereto. The selection of electrical output parameters from the energy source 112 to monitor or control the tissue ablation process can vary widely depending on the tissue type, the experience, technique and/or preference of the operator.

The tissue ablation system 100 may include a number of other components, such as a controller (not shown) that semi-automatically or fully automatically controls the delivery of energy from the energy source 112. For example, the controller may increase power output to the energy conduits 108, control temperature when the energy conduits 108 include temperature sensors or receive temperature from remote sensors, and/or monitor or control impedance, power, current, voltage, and/or other output parameters. The controller's functionality may be integrated with the functionality of the energy source 112, may be integrated with other components of the tissue ablation system 100, or may be in the form of a separate device connected between components of the tissue ablation system 100, but is not limited thereto.

In addition, the tissue ablation system 100 may include an operator display (not shown) that displays heating parameters such as temperature of one or more energy conduits 108, impedance of the energy source 112 output, power, current, voltage, timing information, and/or voltage. The display may be integrated with the functionality of energy source 112, integrated with other components of tissue ablation system 100, or may be in the form of a separate device connected between components of tissue ablation system 100, but is not limited thereto.

In operation, the user moves the deployment slider 104 forward and, in response, the energy conduits 108 are forced into the deployed state, or released from the stowed state to the deployed state in the case of pre-shaped energy conduits. As shown in fig. 2, the shape of the deployed energy conduits may form a series of approximately hemispherical quadrants which when folded together form a spherical profile. The tissue ablation device produces a spherical volume of ablated tissue upon application of energy to the deployed electrodes.

Fig. 3 is a distal portion of a tissue ablation device 101 according to the embodiment of fig. 1, including a delivery member/tube 106, a deployment member or rod 112, a plurality of energy conduits 108 in a stowed state (only two energy conduits are shown for simplicity, but the embodiment is not so limited), and a distal tip 110. The energy conduits 108 are individually or collectively connected to an energy source or generator (not shown). When the energy conduits 108 are in the stowed state, the distal portion of the tissue ablation device presents a very streamlined profile that is well suited for penetrating tissue, advancing/deploying into or near an area that may contain a malignant or non-malignant tumor. By penetrating the tumor, the distal tip may be placed just outside the tumor.

Fig. 4 is a distal portion of a tissue ablation device 101 according to the embodiment of fig. 1, including a delivery member/tube 106, a deployment member or shaft 102, a plurality of energy conduits 108 in a deployed state, and a distal tip 110. The energy conduits 108 are individually or collectively connected to an energy source or generator (not shown). After the distal portion of the tissue ablation device is positioned in the target tissue suitable for the associated medical procedure, the user moves a deployment sled (not shown) forward to deploy the energy conduits 108 to completely encompass the volume of tissue to be ablated.

With respect to deployment of the energy conduits 108, some or all of the energy conduits 108 may be deployed in response to advancement of the deployment sled. For example, all of the energy conduits 108 in one embodiment deploy simultaneously in response to advancement of the deployment sled. As another example, one set of energy conduits 108 may be deployed to form a sphere having a first diameter, and another set of energy conduits 108 may be deployed to form a sphere having a second diameter. Other alternative embodiments may use other deployment schemes known in the art.

The energy conduits 108 of one embodiment deliver Radio Frequency (RF) current to the target tissue, again with alternating current polarity. The alternating polarity sequence of the energy conduits comprises a sequence combination of various alternating polarities. For example, in an embodiment using 10 energy conduits, the alternating polarities are: positive (+) and negative (-) polarities (+), +, -, +, -, +, -, and-are shown. One alternative polarity sequence is: +,+, -, -,+,+, -, -,+,+. Yet another alternative polarity sequence is: -, -,+,+, -, -,+,+, -, -. Yet another alternative polarity sequence is: +,+,+,+,+, -, -, -, -, -. These examples are merely illustrative of possible polar configurations and the tissue ablation system 100 described herein is not limited to 10 electrodes or these alternating polar configurations.

The energy conduits of an alternative embodiment conduct current having a single electrical polarity, while the deployment rod 112 conducts current having a polarity opposite to that of the energy conduits. In another alternative embodiment, the deployable energy conduits are switched between the same electrical polarity (with the deployment rod of the other polarity) and alternating polarity (between the deployable energy conduits). In yet another embodiment, the deployment rod and the deployable energy conduits have a single electrical polarity and are used simultaneously with one or more secondary ground pads to provide members of opposite polarity.

Various alternative embodiments may use any number of energy conduits simultaneously in a procedure to create a volume of ablated tissue shaped and sized for the treatment procedure. Those skilled in the art will recognize that there are a number of alternatives to the tissue ablation devices described herein.

Fig. 5 shows a distal region or distal portion of the tissue ablation device 101 according to the embodiment of fig. 1, including a central deployment rod 112, a plurality of energy conduits 108 in a deployed state (only two energy conduits are shown for simplicity, but the embodiment is not so limited), a conduit insulator 504, and a distal tip 110. To support the delivery of electrical energy of alternating polarity through the energy conduits 108, the conduit insulator 504 is mechanically coupled to the distal ends of the energy conduits 108 while maintaining electrical isolation between each energy conduit 108. In this tissue ablation device, a deployable energy catheter 108 is connected to a catheter insulator 504. The combination of the energy conduit 108 and the conduit insulator 504 is connected to the non-conductive retention disc 502, which is connected to the conductive deployment member 112. Also attached to the deployment member 112 in this embodiment is a conductive distal tip 110 adapted to pierce tissue. The deployment slider is moved forward so that the deployable energy conduits or electrodes 108 are subjected to compressive loads. When this force increases to greater than the column strength of the deployable energy conduits 108, the energy conduits 108 bend and deploy outward in a controlled manner.

Alternatively, the energy conduits 108 may be pre-formed into a desired shape when made of a suitable material, such as nickel titanium alloy (NiTi). With a pre-shaped electrode, moving the deployment slider forward allows the deployable electrode to resume the pre-shaped shape. Application of a small amount of energy, such as RF current, can help facilitate deployment of the electrodes through tissue.

Fig. 6 shows a mid-section of a tissue ablation device 101 according to the embodiment of fig. 1, including a delivery member/tube 106, a deployment member 112, and a plurality of energy conduits 108 in a deployed state (for simplicity, only two energy conduits are shown, but the embodiment is not so limited). The proximal end 604 of the energy conduit 108 is coupled to the electrical insulator 602 or insulating material 602, but is not so limited.

Fig. 7 shows an exploded view of the distal region of the tissue ablation device 101 including a rotated side view of the deployment member 112, the distal tip 110, and the energy catheter retention disc 502 according to the embodiment of fig. 1. While there are a variety of methods of connecting the components of the tissue ablation device 101 at the distal tip, one such method is to configure a simple thread 702 to receive the distal tip of the deployment member 112. Alternatively, press fit or interference fit between the mating parts or the use of various adhesives may be employed. The retention tray 502 described above with reference to fig. 5 is configured to couple with the deployment member 112 and the distal tip 110.

Fig. 8 is an end view of the tissue ablation device 101 with the energy conduits 108 deployed according to the embodiment of fig. 1, the energy conduits 108 forming a sphere having diameters of about 5, 6, and 7 centimeters. The tissue ablation device 101 of one embodiment provides substantially uniform spacing between the energy conduits 108, but alternative embodiments may support any number/combination of energy conduit 108 configurations. The tissue ablation device 101 of one embodiment provides control over the degree of deployment of the deployable energy conduits by the deployment sled to support a variety of spherical deployment sizes, but is not so limited.

Fig. 9 is a cross-section of an energy conduits 900 according to an embodiment, the energy conduits 900 being configured to at least one of cut, separate and divide tissue when pressed or impacted against the tissue. The energy conduits 900 are used to form the energy conduits 108 described above with reference to fig. 1. As the energy conduits 900 are advanced from the stowed state (fig. 3) to the deployed or expanded state (fig. 4), the energy conduits 900 penetrate or separate the surrounding tissue. In one embodiment, such penetration is accomplished by using an energy catheter having a geometry suitable for separating or cutting the surrounding tissue. In an alternative embodiment, penetration of the tissue by the energy conduits 900 is accomplished by applying energy, such as RF energy, to the energy conduits 900, thereby facilitating the energy conduits to cut tissue as they are advanced. Another alternative embodiment includes using an energy conduit 900 having a cutting geometry and simultaneously applying suitable electrical energy to the energy conduit 900.

Fig. 10 is a distal portion 1000 of a tissue ablation device according to an alternative embodiment, including a delivery member/tube and a plurality of energy conduits a, B, C, D, E, F, and G (collectively referred to as a-G) in a deployed state. For example, the energy conduits a-G comprise nitinol, but may be formed from any number/combination of materials. Further, the energy conduits A-G of one embodiment have an outer diameter of about 0.010 to 0.040 inches, but are not so limited.

As described above, the delivery member/tube 1006 provides sufficient support for the configuration of the energy conduits a-G. Advancement of a deployment sled (not shown) advances and deploys the energy conduits a-G to a deployed shape. The shape of the energy conduits a-G may form a series of approximately hemispherical quadrants, which in one embodiment, when brought together, form the outline of a sphere 1099 that completely encompasses the targeted ablated tissue volume. Application of RF energy to the energy conduits a-G generates or forms a spherical volume of ablated tissue.

The energy conduits a-G in one embodiment are configured such that each energy conduit has an alternating electrical polarity. The energy conduits of an alternative embodiment have a single electrical polarity, while the delivery member/tube 1006 conducts an opposite polarity. In another alternative embodiment, the energy conduits a-G are independently switched between the same electrical polarity and the delivery member/tube 1006 delivers opposite/alternating polarity to the energy conduits a-G. In yet another alternative embodiment, the delivery member/tube 1006 and energy conduits a-G have a single electrical polarity and are used with one or more secondary ground pads to provide members of opposite polarity.

In operation, the tissue ablation system of one embodiment delivers energy to the target tissue through the energy conduits a-G. For example, the energy includes Radio Frequency (RF) energy, but is not limited thereto. The energy is delivered by any of a variety of techniques. The energy may be applied by a pulsed waveform and/or a continuous waveform, but is not limited thereto.

In one example procedure involving use of the tissue ablation system, energy can be applied to the energy conduits A-G during deployment of the energy conduits A-G into the target tissue. The energy may be applied automatically as the procedure progresses and in a manner appropriate for the procedure, or alternatively, manually. Also, the energy delivered to the target tissue can be adjusted during the procedure by adjusting any of the power level, the waveform, and the combination of the power level and the waveform.

In another example procedure involving use of the tissue ablation system, energy can be applied to the energy conduits A-G after deployment of the energy conduits A-G into the target tissue. The energy may be applied automatically in a manner appropriate to the procedure, or alternatively, manually. Also, the energy delivered to the target tissue can be manually and/or automatically adjusted during the procedure by adjusting any of the power level, the waveform, and the combination of the power level and the waveform.

In addition to the components of the tissue ablation device 1000, various sensing techniques may be employed to guide or control the progress of tissue ablation. For example, a temperature sensor may be embedded in or attached to at least one of the energy conduits a-G and the delivery member/tube 1006 to provide feedback to a user and/or an energy controller. In addition, a variety of sensors can be deployed from the tissue ablation device 1000 into the tissue of the target tissue.

In addition to the components of the tissue ablation system described above, various sensing techniques may be used with and/or in conjunction with the tissue ablation system to guide or control the progress of the tissue ablation. For example, a temperature sensor can be embedded in or attached to the deployable energy conduit and provide feedback to the user and/or the energy controller. Various sensors may also be deployed from the device into tissue within the target tissue, in this case a sphere.

Fig. 11 is a distal portion 1100 of a tissue ablation device according to another alternative embodiment, including a delivery member/tube 1106, a plurality of primary energy conduits R, S, T, U, W, X, Y, Z (collectively R-Z), and a secondary energy conduit H, I, J, K, L, M, N in a deployed state, and P (collectively H-P) and Q. For clarity, electrodes H, I, K, M, P, S, T, U, X, Y, and Z have been omitted from the side view of the device shown in FIG. 11. For example, the primary R-Z and secondary H-P energy conduits comprise nitinol, but may be formed from any number of materials or any combination of materials, some of which are described above. Further, the primary R-Z and secondary H-P energy conduits of an embodiment have diameters of about 0.010 to 0.080 inches, but are not so limited.

As described above, the delivery member/tube 1106 provides sufficient support for placement of the primary energy conduits R-Z. Also, the primary energy conduits R-Z provide sufficient support for placement of the secondary energy conduits H-P. While the tissue ablation device of one embodiment deploys one secondary energy catheter from one or more distal ends and/or sides in the distal region of each primary energy catheter, alternative embodiments of the tissue ablation device may deploy more than one secondary energy catheter from one or more distal ends and/or sides in the distal region of each primary energy catheter. As previously described, advancement of the deployment sled (not shown) advances the energy conduits R-Z, H-P and Q into the target tissue and into a deployed state or deployed shape. The energy conduits R-Z, H-P in the deployed state form a series of approximately hemispherical quadrants, which when brought together in this embodiment form spheres 1199 that completely surround the ablation volume of the target tissue. Application of RF energy to the energy conduits R-Z, H-P and Q generates or forms a spherical ablated tissue volume.

The energy conduits R-Z, H-P and Q of an embodiment are configured such that each energy conduit has an alternating electrical polarity. The energy conduits of an alternative embodiment transmit electrical energy having a single electrical polarity, while the delivery member/tube 1106 delivers electrical energy having an opposite polarity. In yet another alternative embodiment, the energy conduits H-P and R-Z are independently switched between the same electrical polarity and the electrode Q is connected to deliver electrical energy of opposite/alternating polarity to the energy conduits H-P and R-Z. In yet another alternative embodiment, all of the energy conduits R-Z, H-P and Q have a single electrical polarity and are used with one or more secondary ground pads to provide members of opposite polarity. In another embodiment, electrode Q is absent and energy is passed in the remaining electrodes.

In operation, the tissue ablation system of one embodiment delivers energy to the target tissue through the energy conduits R-Z, H-P, and Q. For example, the energy includes Radio Frequency (RF) energy, but is not limited thereto. The energy is delivered by any of a variety of techniques, some of which are described herein. The energy may be applied by a pulsed waveform and/or a continuous waveform, but is not limited thereto.

In one example procedure involving the use of the tissue ablation system, energy conduits R-Z, H-P and Q may be energized during deployment of the energy conduits R-Z, H-P and Q into the target tissue. The energy may be applied automatically as the procedure progresses and in a manner appropriate for the procedure, or alternatively, manually. Also, the energy delivered to the target tissue can be adjusted during the procedure by adjusting any of the power level, the waveform, and the combination of the power level and the waveform.

In another example procedure involving the use of the tissue ablation system, energy can be applied to energy conduits R-Z, H-P and Q after deployment of the energy conduits R-Z, H-P, and Q into the target tissue. The energy may be applied automatically in a manner appropriate to the procedure, or alternatively, manually. Also, the energy delivered to the target tissue can be manually and/or automatically adjusted during the procedure by adjusting any of the power level, the waveform, and the combination of the power level and the waveform.

In addition to the components of the tissue ablation device 1100, various sensing techniques may be employed to guide or control the progress of tissue ablation. For example, temperature sensors may be embedded in or attached to at least one of the energy conduits R-Z, H-P and Q and the delivery member/tube 1106 to provide feedback to a user and/or an energy controller. In addition, a variety of sensors can be deployed from the tissue ablation device 1100 into the tissue of the target tissue.

In addition to the components of the tissue ablation system described above, various sensing techniques may be used with and/or in connection with the tissue ablation system to guide or control the progress of the tissue ablation. For example, a temperature sensor can be embedded in or attached to the deployable energy conduit and provide feedback to the user and/or the energy controller. Various sensors may also be deployed from the device into tissue within the target tissue, in this case a sphere.

Fig. 12 is a flowchart of a tissue ablation procedure using a tissue ablation device, in accordance with one embodiment. In operation, typically a user positions a tissue ablation device within a target biological tissue suitable for performing a medical procedure, block 1202. Placing the tissue ablation device within the target tissue may include, but is not limited to, using various imaging methods such as sonography, Computed Tomography (CT), and Magnetic Resonance Imaging (MRI).

After placing the device in the target tissue, the user deploys the electrodes in the target tissue, block 1204. Power or energy is applied to the target tissue via the electrodes, see block 1206. The energy produces an ablated tissue volume having a shape and size suitable for the deployed electrode structure, see pane 1208. The user retracts the electrodes and removes the device from the target tissue, block 1210.

In one or more other embodiments, the tissue-ablating electrode may be configured to at least partially surround the target tissue depending on the location and distribution of the target tissue to be ablated. For these embodiments, one or more monopolar or bipolar electrodes may be configured to completely encompass or partially encompass a target tissue, such as a tumor, and application of energy through the electrodes directly produces a spherical or relatively spherical ablation zone surrounding and including the target tissue. Such relatively spherical regions may comprise elongated spherical regions (e.g., diamonds). The ablation region may also include a closed compound curved surface. One or more ablation devices, each containing one or more electrode arrays, are used to encompass at least a portion of the target tissue or ablation volume and thereby ablate the portion upon deployment of the electrodes and application of energy from the energy source. Thus, each such device produces an ablation pattern along one or more planes of the target tissue or ablation volume, and the device may be referred to as a "planar" device or electrode assembly.

Fig. 13 illustrates a helical electrode ablation device according to an embodiment. The device 1300 includes a trocar 1302, or similar piercing device (also referred to as an "introducer" or "delivery member"). Generally, trocars are sharp-pointed rods with three-sided tips and can be placed in a cannula for insertion into body tissue; however, trocar 1302 may represent any suitable introducer or puncture device that can house one or more electrode elements. The first electrode 1304 extends from the distal end of the trocar 1302 in a helical configuration and in a plane perpendicular to the longitudinal axis of the trocar 1302. A second electrode 1308 also extends from the body of the trocar 1302 in a helical configuration and is parallel to the electrode 1304. A third electrode 1306 is positioned between the first and second electrodes 1304 and 1308 and extends in a spiral configuration and parallel to these electrodes. The diameter of electrode 1306 is larger than the diameter of electrodes 1304 and 1308 so that the ablation pattern on target tissue 1310 is spherical or nearly spherical. By varying the relative sizes of electrodes 1304, 1306 and 1308, as well as the relative positions on the trocar, ablation patterns of various shapes and sizes can be produced. Generally, the electrodes 1304 and 1308 are equal in diameter, and the electrode 1306 is larger in diameter than the two terminal electrodes. The spacing between the electrodes may be equidistant or offset so that electrode 1306 is closer to one end electrode or the other. Electrodes 1304, 1306 and 1308 may be energized to have a particular polarity with respect to each other. In one embodiment, terminal electrodes 1304 and 1308 can be negatively charged while intermediate electrode 1306 is positively charged, or vice versa.

The trocar 1302 is configured and used to initially position the target tissue site 1310 and is connected to an energy source, such as an RF generator having a suitable frequency, to ablate the target tissue through the electrodes. By including a dispersion pad, the device 1300 can be used as a monopolar or bipolar device. Thermal sensors may be included in one or more of the electrodes for feedback or control, as well as impedance sensors for this purpose. One or more of the electrodes 1304, 1306 and 1308 can be made of an electrically conductive material, such as stainless steel, NiTi, etc., and can be formed in the form of round-section wire, flat wire, round tube, or flattened tube. For the embodiment shown in fig. 13, a three electrode configuration is shown. Alternatively, only two electrodes of the same or different polarity may be used to create a non-precisely spherical ablation pattern around the target tissue 1310, or more than three electrodes with different polarity configurations may be used to further modify or define the ablation pattern. The electrodes are shown in FIG. 13 as lying in a plane perpendicular to the axis of the trocar 1302, although one or more of the electrodes may be offset at an angle relative to the axis to further modify or define the ablation pattern. In addition, the number of coils making up the electrode can be varied to accommodate different energy sources and to meet the requirements of the target tissue.

In yet another alternative embodiment of the device shown in FIG. 13, one or more helical devices can be configured to deploy along the body of a trocar 1302 by spiraling around the trocar in a direction parallel to the longitudinal axis of the trocar.

The structure and composition of an ablation device configured to surround or at least partially surround a target tissue may be achieved by various embodiments. Fig. 14 illustrates a combination electrode ablation device including a fluid path according to an embodiment. With device 1400, two or more separate electrodes extend from the distal end of trocar 1402. Each electrode includes a combined electrode having a positively charged portion and a negatively charged portion connected by an insulating member. Thus, fig. 14 shows a device in which the first electrode comprises a first portion 1403 and a second portion 1404 having an insulating member 1405 and the second electrode comprises a first portion 1406 and a second portion 1409 having an insulating member 1407. First portions 1403 and 1406 can apply energy to a first polarity (e.g., negative polarity) and second portions of the electrodes can apply energy to an opposite polarity (e.g., positive polarity). A second portion (e.g., 1404) of the electrode may fit within and deploy through a lumen of a first portion (e.g., 1403) of the electrode; inserting an insulating sleeve (e.g., 1405) around the cavity to maintain electrical insulation also allows the second electrode portion to be physically supported in the first electrode portion.

Although two bipolar electrodes are shown in FIG. 14, it should be noted that a plurality of such combined electrodes may extend from trocar 1402 or be replaced with a plurality of monopolar electrodes. Furthermore, the cannula needle itself can be connected to an additional electrode. For the embodiment shown in FIG. 14, electrode 1408 is connected to the body of trocar 1402 and is electrically isolated from electrodes 1404 and 1406 and 1402. A fluid path 1410 is formed between the trocar 1402 and the electrode 1408 to deliver a fluid, such as electrically conductive saline. Discrete electrodes may be included in the device 1400 to form a monopolar device or a monopolar/bipolar device.

In one embodiment, the ablation device may be formed by the process of: one electrode is defined as a portion of a trocar and energized to have a polarity and one or more electrodes configured to extend from an end or portion of the trocar body are of opposite polarity. The device creates an ablation pattern in a tissue region near the trocar when the extended electrodes are deployed and energized relative to electrodes formed within the trocar body. Thus, with reference to the embodiment of FIG. 14, if electrode 1408 has a negative polarity and one or both of electrodes 1404 and 1406 and 1402 have a positive polarity, deployment and application of energy to the electrodes will result in ablation of the area surrounding the electrodes. The shape and size of the regions can be defined by varying the number, length or size, and configuration of the electrodes, as well as the type and power of the energy source. For the embodiment shown in fig. 14, where electrodes 1403/1404 and 1406/1409 are themselves combined electrodes, it may not be necessary to provide separate electrodes of a particular polarity (e.g., electrode 1408) to form a bipolar device. Also, the electrodes 1408 may be connected by a conductive fluid 1410 as shown, or they may be integrally molded or adhesive based with a second insulating member (not shown) to maintain electrical insulation between the electrodes and the trocar body 1402.

To form electrodes that can have two or more polarities in a single element, the projecting electrodes shown in fig. 13 or 14 can be made of a flat substrate, such as a spring/metal sheet or the like. A conductive coating may be applied to the substrate through an insulating layer such that a single electrode may be configured to have two different polarities upon application of energy.

Fig. 15A is a two-stage ablation device for surrounding a target site according to one embodiment. The device 1500 includes a set of electrode arrays deployed from a trocar 1502 to at least partially surround a target tissue 1510. The first set of electrodes 1504 and 1505 constitutes stage 1 of the array and the second set of electrodes 1506 and 1507 constitutes stage 2 of the array. The stage 2 electrode is mechanically connected within the stage 1 electrode and extends from the stage 1 electrode in a telescoping manner when deployed. The stage 1 electrodes 1504 and 1505 may be comprised of circular or oval tubes that may be formed in a suitable shape and size to accommodate the internal stage 2 electrodes. The level 2 electrodes 1506 and 1507 may be comprised of round or flat wires that conform to the internal dimensions and shape of the level 1 electrodes.

Multiple stage 1 and stage 2 electrodes can be configured to be deployed from the tip of the trocar 1502 to surround the target tissue 1510 and create a suitable ablation pattern 1512. Fig. 15B shows an end view of the ablation device of fig. 15A with four flat wire electrodes 1514 deployed from the end of the trocar 1502 in a square pattern, according to one embodiment. Fig. 15C shows an end view of the ablation device of fig. 15A in accordance with an alternative embodiment, wherein 12 electrodes 1516 are deployed from the end of the trocar 1502 in a relatively circular pattern. As can be seen in fig. 15B and 15C, the more electrodes deployed, the more nearly circular the pattern created around the trocar tip, thereby creating a more spherical ablation pattern 1512 around the target tissue 1510.

In the embodiment shown in fig. 15A, the electrode is configured to at least partially surround the target tissue. In an alternative embodiment, one or more electrodes may be configured to penetrate the target tissue while other electrodes surround the tissue to create an ablation pattern 1512. Fig. 16A shows an ablation device including a surrounding electrode and a piercing electrode according to one embodiment. In the device 1600, the electrodes 1604 and 1606 are configured to surround the target tissue 1610 when deployed from the trocar 1602 to form an ablation pattern 1612. A piercing electrode 1608 is deployed from the distal end of the trocar 1602 and includes a piercing member for piercing the target tissue 1610. The electrodes 1604, 1606 and 1608 may be configured as monopolar or bipolar electrodes to form a monopolar or bipolar device. One or more of the electrodes may also include a fluid delivery element for delivering fluid to the target tissue. This is shown in fig. 16B, where trocar 1603 includes fluid delivery element 1618. The element 1618 may be a delivery tube that is electrically neutral with respect to the other electrodes 1616 and 1619, or may be an electrode having a lumen that applies energy to a particular polarity with respect to the other electrodes 1616 and 1619 and/or the cannula needle 1603.

In general, a plurality of individual surrounding electrodes may be configured to extend from the side or end of the trocar. Fig. 17 shows an ablation device with electrodes extending from the side of the trocar. As shown in fig. 17, four electrodes 1702-1708 extend substantially laterally from the side of the trocar 1700 to at least partially surround the target tissue. Electrodes 1702-1708 may be electrically isolated from each other to form a bipolar system, and various electrode polarity combinations may be fabricated for bipolar ablation. For example, the polarities of the four electrodes 1702, 1704, 1706, and 1708 may be: , +, +, -, or +, -, +, -, or-, -, +, +, etc. In one embodiment, the generator connected to the cannula needle 1700 may have multiple channels so that each electrode may have independent power levels and associated impedance or thermal sensing capabilities. Based on system feedback, the polarity and relative power level of each electrode can be switched or changed by a control circuit or control software.

In an alternative embodiment to the embodiment shown in fig. 17, the electrodes may be configured to extend from the distal end of the trocar. Fig. 18 shows an ablation device with electrodes deployed from the trocar tip. As shown in fig. 18, four electrodes 1802 and 1808 extend generally laterally from the top of the trocar 1800 to at least partially surround the target tissue.

As shown in fig. 17 and 18, the electrodes may be relatively straight metal strips that are deployed from the side or end of the trocar to surround the target tissue region. In some examples, more complex target tissue surrounding may be achieved using curved or spiral electrodes. Fig. 19A is a side view of an ablation device with a helical electrode deployed from the tip of a trocar. Figure 19B is a top view of the embodiment shown in figure 19A showing the electrodes surrounding the target tissue. As shown in fig. 19A, electrodes 1904 and 1910 extend outwardly from the end opening of the trocar 1902. The device shown in FIG. 19A has four electrodes, although any number of electrodes may be shown, for example 2-6 electrodes. Fig. 19B is a top view showing an example of how the two electrodes 1904 and 1906 surround the target tissue 1912. The spacing and length of the electrodes when deployed may be configured to suit a particular application. Also, as shown in FIG. 19B, the length and tightness of each electrode spiral is different from one another, depending on the particular needs and application. The polarity of the spiral electrodes may be arranged as positive or negative electrodes in a uniform or alternating manner, for example electrodes 1904-1910 may be arranged as +, -, -or +, -, -etc., respectively.

For the embodiment shown in fig. 19A, each electrode is shown as a single element electrode. In an alternative embodiment, one or more of the electrodes may be a composite electrode comprising a first stage having one polarity and a second stage having an opposite polarity, such as the embodiment shown in fig. 15A. For this embodiment, the second secondary electrode may be housed within the first primary electrode by a mechanical connection that maintains electrical isolation of the two nested electrodes. Fig. 20 illustrates an ablation system with a combination helical electrode, according to one embodiment. In FIG. 20, the primary electrode 2002 is deployed extending from the end of the trocar 2000. The second secondary electrode 2004 extends across the electrode 2002 in a curved or helical direction to surround the target tissue 2010. The insulating barrier 2006 electrically isolates the electrode 2002 and the electrode 2004 to form a bipolar device, where the electrode 2002 has a first polarity (e.g., a positive pole) and the electrode 2004 has an opposite polarity (e.g., a negative pole). Alternatively, the electrodes 2002 and 2004 may protrude together from the end of the trocar 2000 when deployed.

Fig. 21 shows a helical electrode ablation device according to a second alternative embodiment. For the embodiment shown in fig. 21, two helical electrodes 2102 and 2104 extend from the end of the trocar 2100 when deployed. Rather than each electrode surrounding the target tissue 2110, they each surround one side or plane of the target tissue, so that all of the electrodes together create an ablation region surrounding the target tissue. Each electrode individually forms a partially spherical pattern around the target tissue. When energy is applied, they together form a spherical or relatively spherical ablation pattern. The electrodes used as shown in fig. 21 may have a monopolar or bipolar configuration.

Although the embodiment shown in fig. 21 shows 2 helical electrodes, it should be noted that more electrodes (e.g., 4 or 6) of similar configuration may be provided to define an ablation zone around the target tissue. In general, for any embodiment that includes a coiled electrode, it should be noted that the electrode may be made of a material that allows it to be preformed, such as a shape memory metal, a spring, a flat wire, and the like.

For the embodiment shown in any of figures 13-21, the electrodes can be deployed by a trigger in the handle connected to the end of the trocar, as shown in figure 1. The electrodes in the device are connected to lead wires or other transmission mechanisms. These electrodes are deployed by moving the guide wire outward and are retracted by pulling the guide wire back into the trocar. A gear mechanism connects a trigger such as a slider or button (e.g., actuator 104 shown in fig. 1) to the lead or similar push/pull rod that extends or retracts the electrode.

The devices shown in the embodiments of FIGS. 13-21 generally illustrate a single trocar device. In one embodiment, an ablation device comprising a plurality of electrodes configured to surround a target tissue or volume of ablated tissue may comprise more than one trocar, wherein each trocar contains one or more electrodes surrounding the target tissue or portion of the target tissue. Two or more trocars may be connected to a single handle and trigger, or the trocars may each be connected with their own handle and trigger. Typically, a user manipulates two or all of the trocar bodies comprising a multi-trocar device to place electrodes around the target tissue or within the tissue volume to create a desired ablation pattern.

Fig. 22 illustrates a combination ablation device including two independent trocars for surrounding or partially surrounding a target tissue or defining an ablation pattern, according to one embodiment. Trocar 2202 and trocar 2204 are deployed in a side-by-side fashion such that respective electrode arrays 2206 and 2208 surround the target tissue. The trocars may be rotated relative to each other as desired, such as with the electrodes facing each other as shown, away from each other, or in any direction relative to each other. The shape, length, composition and number of electrodes in the electrode array may be configured according to the application or characteristics of the target tissue. For example, the electrodes may be straight, as shown in arrays 2206 and 2208. Alternatively, the electrodes may be helical electrodes, or a combination of straight and helical electrodes. Each individual trocar may have the same array structure for a symmetric system or each trocar may employ a different structure of electrodes for an asymmetric system. The polarities of these arrays may be opposite to each other, such as shown in fig. 22, where electrode array 2206 is negatively charged and electrode array 2208 is positively charged, or each array may include electrodes of different polarities. In operation, the electrode array is configured to define an ablation region around a portion of the target tissue such that together they form a complete or spherical ablation pattern around the target tissue. As shown in fig. 22, each trocar is connected to its own handle, which may include a trigger for deploying the respective electrode. Alternatively, the two cannula bodies 2202 and 2204 may be connected by a handle to position and deploy the electrodes.

In one embodiment, a guide structure may be provided to connect trocar bodies such as trocars 2202 and 2204 in a fixed orientation relative to one another. This stabilizes the trocar and allows the user to independently deploy the electrodes of the trocar without the need to laterally stabilize the trocar when deployed. The guide structures can be configured to allow the trocars to slide longitudinally relative to each other so that one trocar can extend farther within the tissue relative to the other. The guide structure may be further configured to allow some movement of the trocar bodies closer together or further apart, or even to allow one trocar to pivot relative to another trocar.

The electrode array of each trocar may extend from either the end or the side of the device (as shown in fig. 17 and 18), or both. Further, the electrodes in each array may be a single device of a single polarity, or a composite device having a portion of a first polarity and a second portion of an opposite polarity.

Fig. 23A shows a multi-trocar ablation device using one or more helical electrodes in an array extending from the distal end of each trocar. The illustrated device includes a first trocar 2302 having two or more helical electrodes 2304 and 2305 extending from an end of the trocar at a particular angle relative to a longitudinal axis of the trocar. The second trocar 2306 also has two or more helical electrodes 2308 and 2309 projecting from the end of the trocar at a particular angle relative to the longitudinal axis of the trocar. The angle of extension and the electrode array itself are shaped and configured to surround the target tissue 2310 and create a spherical or near-spherical ablation pattern within the tissue volume surrounding the target tissue 2310. Fig. 23B is an end view of the multiple trocar ablation device of fig. 23A. As shown in fig. 23B, electrodes 2304 and 2305 extend from trocar body 2302 at an angle 2312 relative to each other as defined by the longitudinal axis of the trocar; and the electrodes 2308 and 2309 extend from the trocar body 2306 at an angle 2314 relative to each other as defined by the longitudinal axis of the trocar. The angle at which the electrode pairs are deployed relative to each other, as well as the length of the electrodes and the tightness of the helix, may vary depending on the application and the characteristics of the target tissue 2310. The electrodes may each have a single polarity, with alternating polarity electrodes being used in each electrode pair or array for each trocar, or the electrodes may be combination electrodes having different polarity portions within each electrode. Thus, for example, for the embodiment shown in fig. 23B, electrodes 2305 and 2309 may both be positively charged, electrodes 2304 and 2308 may both be negatively charged, or electrodes 2305 and 2308 may both be positively charged while electrodes 2304 and 2309 are negatively charged.

Figure 24A shows a multi-trocar system including two single element electrode devices configured to at least partially surround a target tissue. The trocar of fig. 24A is deployed in an opposite manner, with trocar 2402 accessing target tissue 2410 from one side and trocar 2404 accessing target tissue 2410 from the opposite side. The electrode 2403 is deployed from the trocar 2402 to partially surround the target tissue 2410 on one side, while the electrode 2405 is deployed from the trocar 2404 to partially surround the target tissue 2410 from the opposite side of the electrode 2403. Both electrodes produce a partially surrounding ablation pattern that together surround the target tissue 2410 in a spherical or relatively spherical pattern. One or more of the electrodes may extend from the side of the trocar. FIG. 24B shows an alternative embodiment of a multi-trocar system in which an electrode extends through the side of the trocar. As shown in fig. 24B, the electrode 2409 extends through a side opening of the trocar 2408, the trocar 2408 and the trocar 2402 being oppositely disposed about the target tissue 2410.

The size, shape, number and orientation of the electrodes shown in fig. 24A and 24B deployed from the trocar may vary depending on the shape, orientation and location of the target tissue and the access point to the target tissue and ablation region.

While the embodiment of fig. 22 and 23A shows an ablation system including two independent trocar devices, it should be noted that more than two trocars (e.g., 3 or 4) may be used depending on the application and the characteristics of the target tissue. In addition, each trocar in a multi-trocar ablation system may use a different configuration of electrode arrays to access or surround difficult to access target tissue or to surround target tissue having different sizes and configurations.

Fig. 25A shows a side view of a three cannula needle system configured to at least partially surround a target tissue, according to one embodiment. Trocar 2502 deploys electrode array 2503, trocar 2504 deploys electrode array 2505, and trocar 2506 deploys electrode array 2507. The shape and orientation of the electrodes in each electrode array is such that, upon application of energy, the electrodes of each trocar produce an ablation pattern that constitutes a partially spherical pattern. The three trocars are oriented or directed within the ablation region around the target tissue such that their respective electrode arrays together create a spherical or relatively spherical ablation region. FIG. 25B shows an end view of the three trocar system shown in FIG. 25A. As can be seen in fig. 25B, the three electrode arrays are arranged in a generally triangular orientation relative to each other so as to surround the target tissue and/or create a relatively spherical ablation pattern. It should be noted that the electrodes shown in fig. 25A and 25B may be straight electrodes, spiral electrodes, single element electrodes, or combined electrodes, or any combination of these. The composition and configuration of these electrodes, as well as the polarity of the respective electrodes relative to each other or to any other trocar electrode, may be set to either a positive or negative polarity depending on the requirements of the target tissue or region.

Although fig. 25B shows a triangular orientation of the three trocar system, it should be noted that any two or three trocars may be oriented at any position relative to each other such that their electrodes create an area sufficient to surround the target tissue or create a desired ablation pattern. For example, two trocars may be placed on either side of the target tissue to create a relatively spherical or elongated spherical ablation pattern substantially surrounding the target tissue. If the target tissue or region is large enough, the trocars may be arranged with their respective electrode arrays located at opposite ends of the target tissue to ablate a portion of the target tissue or a target tissue plane.

As described above, the tissue ablation system of one embodiment delivers energy to the target tissue through an energy catheter or electrode. The energy includes, for example, Radio Frequency (RF) energy, but is not limited thereto. For example, other types of energy may include microwave energy. The energy is delivered by any of a variety of techniques. The energy may be applied by a pulsed waveform and/or a continuous waveform, but is not limited thereto.

In one example procedure that includes use of the tissue ablation system, energy can be applied to the energy conduits during deployment of the energy conduits into the target tissue. The energy may be applied automatically as the procedure progresses and in a manner appropriate for the procedure, or alternatively, manually. Also, the energy delivered to the target tissue can be adjusted during the procedure by adjusting any of the power level, the waveform, and the combination of the power level and the waveform.

In another example procedure involving use of the tissue ablation system, energy can be applied to the energy catheter after deployment of the energy catheter into the target tissue. The energy may be applied automatically in a manner appropriate to the procedure, or alternatively, manually. Also, the energy delivered to the target tissue can be manually and/or automatically adjusted during the procedure by adjusting any of the power level, the waveform, and the combination of the power level and the waveform.

As described above, the energy applied to the target tissue according to one embodiment is controlled automatically and/or manually according to a variety of procedures. The first type of procedure uses a predetermined pattern of energy delivery according to a schedule. The second type of procedure varies the energy applied to the target tissue volume based on temperature information or feedback parameters of the tissue. A third type of procedure varies the energy applied to the target tissue volume in accordance with impedance information or feedback parameters of the tissue in combination with elapsed time. A fourth type of procedure varies the energy applied to the target tissue volume according to impedance information or feedback parameters of the tissue. A fifth type of procedure varies the energy applied to the target tissue volume based on temperature and impedance information or feedback parameters of the tissue.

It should be noted that patient and procedure selection is the responsibility of the medical professional/user, and the outcome depends on a number of factors, including patient anatomy, pathology, and surgical technique. Use of the tissue ablation devices, systems, and methods described herein may result in localized temperature increases that cause thermal damage to the skin. In addition, tissues or organs adjacent to the ablated tissue may also be thermally damaged. To minimize the likelihood of thermal damage to the skin or adjacent tissue, the physician may introduce temperature-modifying measures as appropriate. These measures may include, but are not limited to, cooling and/or separating tissue using sterile ice packs or saline-wetted gauze. The purpose of tissue ablation may be to destroy tissue inside or surrounding a malignant tissue, such as a tumor with carcinogenic cells.

The tissue ablation devices and methods described herein include a tissue ablation device comprising an energy source; an introducer connected to the energy source, the introducer having a body, a proximal end, and a distal end; and an electrode array coupled to the introducer and comprising a plurality of electrodes, wherein each electrode of the plurality of electrodes is configured to extend from a body of the introducer when moving from a stowed state to a deployed state, and is configured to at least partially surround a portion of a desired ablation at least partially surrounding a target tissue when extending to the deployed state, and to form a relatively spherical ablation pattern within a tissue volume surrounding the target tissue upon application of energy by the energy source.

A tissue ablation device of embodiments includes electrodes extending longitudinally from the distal end of the introducer body or electrodes extending laterally from the introducer body.

The energy source of one embodiment comprises a Radio Frequency (RF) generator.

The tissue ablation devices and methods described herein include a bipolar electrode array configured to be connected to an energy source, wherein the array is configured to create a relatively spherical ablation pattern around at least a portion of a target tissue and around a volume of tissue including the target tissue, and to ablate the target tissue from an outer surface of the target tissue toward an interior of the target tissue upon application of energy by the electrode through the energy source.

The system of one embodiment further comprises a controller connected between the RF generator and the bipolar electrodes to automatically control the energy delivered to each bipolar electrode.

The bipolar electrode in one embodiment comprises a helical metal strip and the electrode array comprises two or more helical metal strips arranged in an alternating polarity sequence comprising at least one bipolar electrode of a first polarity and at least one bipolar electrode of a second polarity in series therewith.

The tissue ablation device of one embodiment includes two or more introducers connected to a single handle and trigger mechanism that allows a user to deploy or stow the electrode array.

An alternative embodiment of the tissue ablation device includes two or more introducers coupled to a handle and a trigger mechanism, respectively, that allow a user to deploy or stow portions of the electrode array coupled to each introducer, respectively.

Unless the context clearly requires otherwise, throughout the description and the claims, the terms "comprise", "comprising", and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; in other words, the meaning of "includes, but is not limited to (including)". Terms used in the singular or plural number also include the plural and singular number, respectively. Furthermore, the terms "herein (herein)", "below (hereunder)", "above (above)", "below (below)" and terms having these meanings refer to the entire text of the present application, and not to any particular part of the present application. When the term "or" is used to recite two or more elements, the term includes all interpretations of the following term: any one of the listed elements, all of the listed elements, and any combination of the listed elements.

The above description of example embodiments of tissue ablation devices and methods is not intended to be exhaustive or to limit the systems and methods to the precise form disclosed. Specific embodiments and examples of the tissue ablation devices and methods described herein are for illustrative purposes, and various equivalent modifications can be made within the scope of the present systems and methods, as will be recognized by those skilled in the art. The teachings of the tissue ablation devices and methods provided herein are also applicable to other medical systems, not just the medical systems described above.

The elements and operations of the various embodiments described above can be combined to provide further embodiments. These and other changes can be made to the tissue ablation devices and methods in light of the above detailed description. For example, the following are one or more examples of additional embodiments of the tissue ablation devices, each of which can be used alone or in combination with other embodiments described herein.

The tissue ablation devices and methods also include making the devices useful for creating ablation in tissue to encompass, surround, or otherwise create a three-dimensional perimeter around a volume of tissue, such as a tumor, without penetrating or traversing the volume.

The tissue ablation devices and methods also include the ability and methods for switching the monopolar or bipolar configuration of the device between different electrodes, thereby creating different sets of active electrodes and creating different current paths after application of energy to the target tissue.

The tissue ablation devices and methods also include the ability and methods for switching between different electrodes for a monopolar or bipolar configuration of the device, thereby creating different sets of active electrodes and creating different current paths after application of energy to the target tissue, and/or continuing to switch in any combination or any number of times.

The tissue ablation devices and methods also include the ability and methods for switching between different electrodes for a monopolar or bipolar configuration of the device, thereby creating different sets of active electrodes and creating different current paths after application of energy to the target tissue, and/or the ability and methods to continue switching in any combination or any number of times, and/or the ability to frequently switch with or without a reduction in applied power.

The tissue ablation devices and methods also include the ability and ability for the monopolar or bipolar configuration of the device to switch between different electrodes, thereby creating different sets of active electrodes and creating different current paths after application of energy to the target tissue, and/or the ability and method to continue switching in any combination or any number of times, and/or the ability to frequently switch with or without a reduction in applied power, and/or the ability and method to vary the applied energy prior to switching.

The tissue ablation devices and methods also include the ability and methods for switching the monopolar or bipolar plate structure of the device between different electrodes, thereby creating different sets of active electrodes and creating different current paths after application of energy to the target tissue, and/or the ability and methods to continue switching in any combination or any number of times, and/or the ability to frequently switch with or without a reduction in applied power, and/or the ability to change the applied energy prior to switching, and/or the methods and capabilities to switch based on fixed or changing tissue characteristics including, but not limited to, tissue temperature, impedance, rate of temperature change, rate of impedance change, and the like.

The tissue ablation devices and methods also include the use of electrode coatings and other methods to locally reduce the impedance around them without significantly reducing the impedance away from the electrode (a few electrode diameters or widths away); for example, energy is applied in a manner and for the purpose of releasing conductive tissue fluids or coating salt crystals on the electrodes.

The tissue ablation devices and methods further include applying energy followed by a reduction or pause time followed by application or reapplication of energy to facilitate application of higher energy. This may be implemented using various waveforms, such as saw-tooth waves, square waves, etc., including but not limited to controlling energy delivery at a zero (0) or near zero level.

The tissue ablation devices and methods further include applying energy followed by a reduction or pause time followed by application or reapplication of energy to facilitate application of higher energy. This may be implemented using various waveforms, such as saw-tooth waves, square waves, etc., including but not limited to controlling energy delivery at a zero (0) or near zero level, and/or increasing energy between other electrodes or electrode pairs, or between some current and other electrodes within the device, while the delivered energy is reduced or eliminated.

The tissue ablation devices and methods further include applying energy followed by a reduction or pause time followed by application or reapplication of energy to facilitate application of higher energy. This may be implemented using various waveforms, such as saw-tooth waves, square waves, etc., including but not limited to controlling energy delivery at a zero (0) or near zero level, and/or increasing energy between other electrodes or electrode pairs while the delivered energy is reduced or eliminated, or some current flow within the device and energy between other electrodes, for any combination, duration, fixed or varying power levels, and for any duration and number of cycles.

The tissue ablation devices and methods also include the use of high energy levels that otherwise cannot be maintained due to increased tissue impedance or tissue charring, followed by a reduction in delivered energy, including a reduction or pause time, followed by application or reapplication of energy to facilitate the application of higher energy. This may be implemented using various waveforms, such as saw-tooth waves, square waves, etc., including but not limited to controlling energy delivery at a zero (0) or near zero level.

The tissue ablation devices and methods also include the ability to change the deployed shape of the electrode, e.g., the diameter of the deployed electrode can be changed by, for example, pulling ("pull wire"), pushing ("push wire"), differential heating element, and subsequent expansion of the off-axis element to obtain various sizes of ablated tissue (e.g., 3 cm diameter, 5 cm diameter, 7.5 cm diameter, and 15 cm diameter).

The tissue ablation devices and methods also include making the devices useful for creating ablation in tissue to encompass, surround or otherwise create a three-dimensional perimeter around a volume of tissue, such as a tumor, without penetrating or passing through the volume, wherein the electrode structure creates a nominal predetermined shape when in a predetermined manner.

The elements and operations of the various embodiments described above can be combined to provide further embodiments. These and other changes can be made in the thermal ablation apparatus and methods in light of the above detailed description.

Claims (35)

1. A tissue ablation device comprising:

an energy source;

an introducer connected to the energy source and having a body, a proximal end, and a distal end; and

an electrode array coupled to the introducer and comprising one or more electrodes, each of the one or more electrodes configured to protrude from a body of the introducer when moved from a stowed state to a deployed state and configured to at least partially surround a portion of a desired ablation that will at least partially encompass a target tissue when extended to a deployed state and form a shaped ablation pattern within a tissue volume surrounding the target tissue when energy is applied by the energy source.

2. The tissue ablation device of claim 1, wherein the electrode extends longitudinally from the distal end of the introducer body.

3. The tissue ablation device of claim 1, wherein the electrode extends from a side of the introducer body.

4. The tissue ablation device of claim 1, wherein the ablation pattern comprises one of a generally spherical pattern, an elongated spherical pattern, and a closed compound curve pattern.

5. The tissue ablation device of claim 1, wherein the electrode comprises a curved metal strip and the electrode array comprises two or more curved metal strips arranged in an alternating polarity sequence comprising at least one bipolar electrode of a first polarity and at least one bipolar electrode of a second polarity in series therewith.

6. The tissue ablation device of claim 5, wherein the electrode comprises one of a flat wire electrode, a circular wire electrode, a flat tube electrode, and a circular tube electrode.

7. The tissue ablation device of claim 5, wherein the electrodes are bipolar electrodes and one or more of the electrodes comprise at least one lumen.

8. The tissue ablation device of claim 1, further comprising an advancement device coupled to the introducer body to control the configuration of the electrode, wherein the electrode is placed in a stowed state with the advancement device prior to placement of the device within the tissue volume, and wherein the electrode is placed in a deployed state with the advancement device.

9. The tissue ablation device of claim 1, wherein the energy generated by the energy source comprises one of radiofrequency energy and microwave energy.

10. A tissue ablation device comprising:

a bipolar electrode array configured to be connected to an energy source;

wherein the array is configured to at least partially surround a portion of a desired ablation that will at least partially encompass a target tissue, and to generate an ablation pattern around a tissue volume that includes the target tissue, and to ablate the target tissue from an outer surface of the target tissue to an interior of the target tissue upon application of energy to the electrode by the energy source.

11. The tissue ablation device of claim 10, wherein the ablation pattern comprises one of a generally spherical pattern, an elongated spherical pattern, and a closed compound curve pattern.

12. The tissue ablation device of claim 11, wherein the energy source connected to the array produces energy of alternating polarity.

13. The tissue ablation device of claim 12, wherein the bipolar electrode comprises a helical metal strip and the electrode array comprises two or more helical metal strips arranged in an alternating polarity sequence comprising at least one bipolar electrode of a first polarity and at least one bipolar electrode of a second polarity in series therewith.

14. The tissue ablation device of claim 12, wherein the bipolar electrode comprises a straight metal strip and the electrode array comprises two or more straight metal strips arranged in an alternating polarity sequence comprising at least one bipolar electrode of a first polarity and at least one bipolar electrode of a second polarity in series therewith.

15. The tissue ablation device of claim 14, wherein the bipolar electrode comprises a first electrode portion connected to a second electrode portion by an electrically insulated physical connector, and wherein upon application of energy from the energy source, the first electrode portion is energized to a first polarity and the second electrode portion is energized to an opposite polarity.

16. The tissue ablation device of claim 11, further comprising a piercing electrode configured to pierce a surface of the target tissue when advanced from the array.

17. The tissue ablation device of claim 11, wherein the array is comprised of two or more array sections contained within two or more introducers, each introducer configured to deploy the array to an extended position upon activation by a user and to retract the array to a retracted position upon retraction by a user.

18. The tissue ablation device of claim 17, wherein the two or more introducers are connected to a single handle and trigger mechanism configured to allow a user to deploy or stow the array.

19. The tissue ablation device of claim 17, wherein the two or more introducers are each coupled to a respective handle and trigger mechanism, each trigger mechanism configured to allow a user to deploy or retract the corresponding array portion through an introducer coupled to the handle.

20. A method of ablating tissue, comprising:

placing a first electrode array around a first portion of a target tissue;

placing a second electrode array around a second portion of the target tissue;

applying energy to the first and second electrode arrays to form an ablation pattern around a tissue volume including the target tissue; and

applying sufficient energy to the first and second electrode arrays to ablate the target tissue from an outer surface to an inner surface of the target tissue.

21. The method of claim 20, wherein the ablation pattern comprises one of a generally spherical pattern, an elongated spherical pattern, and a closed compound curve pattern.

22. The method of claim 21, wherein the first array comprises one or more individual electrodes extending along a first plane of the device and the second array comprises one or more individual electrodes extending along a second plane of the device.

23. The method of claim 22, wherein the first and second arrays are contained in a single introducer device and are deployed by a trigger device connected to a handle connected to the introducer device.

24. The method of claim 22, wherein the first array is contained in a first introducer device and the second array is contained in a second introducer device, wherein the first electrode array is deployed by a triggering device within the first introducer device and the second electrode array is deployed by a triggering device within the second introducer device, wherein a user places the first electrode array relative to the second electrode array by using the triggering device of the first introducer and the triggering device of the second introducer.

25. The method of claim 21, wherein applying energy to the first and second arrays comprises the step of applying radio frequency energy through the first and second arrays.

26. The method of claim 25, further comprising the step of applying alternating polarity to the electrodes comprising the first and second electrode arrays.

27. An apparatus for generating ablation in tissue, comprising:

a trocar assembly;

a handle assembly having a trigger integrated therewith and connected to the trocar assembly; and

a planar electrode assembly coupled to the trocar assembly and configured to be coupled to a source of energy and extendable from a stowed position to a deployed position within the trocar assembly upon activation of the trigger device, the planar electrode assembly being comprised of one or more single electrodes that collectively define a relatively spherical ablation pattern within the tissue upon application of energy from the source of energy.

28. The device of claim 27, wherein the trocar assembly comprises two or more introducer elements, each connected to a respective handle assembly and integrated trigger device, wherein a first portion of the planar electrode assembly is housed in a first introducer element and a second portion of the planar electrode assembly is housed in a second introducer element.

29. The device of claim 28, further comprising a guide element configured to support a first introducer element of the two or more introducer elements and an opposing second introducer element relative to each other to facilitate positioning of the first portion of the planar electrode assembly relative to the second planar electrode assembly.

30. The device of claim 27, wherein the planar electrode assembly comprises two or more helical electrodes extending from the trocar assembly, each helical electrode being energized to a predetermined polarity upon application of energy from the energy source.

31. The device of claim 27, wherein the planar electrode assembly comprises two or more straight electrodes extending from the trocar assembly, each straight electrode being energized to a predetermined polarity upon application of energy from the energy source.

32. The device of claim 27, wherein the planar electrode assembly comprises two or more electrodes extending from the trocar assembly, each electrode having a first portion that is energized to a first predetermined polarity when energy from the energy source is applied and a second portion that is energized to a second predetermined polarity when energy from the energy source is applied.

33. The device of claim 27, wherein the relatively spherical ablation pattern comprises an elongated spherical ablation pattern.

34. The device of claim 27, wherein the energy source is configured to generate energy of alternating polarity to the planar electrode assembly.

35. The apparatus of claim 34, wherein the energy source generates radiofrequency energy.