WO2025235783A1

WO2025235783A1 - Tissue ablation systems and methods to prevent or minimize risk of skin burns by dispersive electrodes

Info

Publication number: WO2025235783A1
Application number: PCT/US2025/028441
Authority: WO
Inventors: Amer HAMMUDI; Oren MOSHER; Diane King; Taraneh Farazi
Original assignee: Gynesonics Inc
Current assignee: Gynesonics Inc
Priority date: 2024-05-10
Filing date: 2025-05-08
Publication date: 2025-11-13
Anticipated expiration: 2026-11-10

Abstract

Disclosed herein is a tissue ablation system configured to reduce a risk of burns on a patient during an ablation procedure. The tissue ablation system can include a radio frequency (RF) generator; an ablation device configured to deliver ablation energy originating from the RF generator to a target tissue; and a plurality of dispersive electrode portions. One or more hardware processors can be configured to: monitor an initial resistance between each of the dispersive electrode portions at a beginning of an ablation; monitor a real-time resistance between each of the dispersive electrode portions during the ablation; monitor a total ablation energy provided from the RF generator to the ablation device; and terminate the ablation in response to determining that the real-time resistance satisfies a condition relative to the initial resistance and the total ablation energy provided from the RF generator to the ablation device exceeds an energy threshold.

Description

TISSUE ABLATION SYSTEMS AND METHODS TO PREVENT OR MINIMIZE RISK OF SKIN BURNS BY DISPERSIVE ELECTRODES

INCORPORATION BY REFERENCE

[0001] All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extend as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference.

BACKGROUND

[0002] The present disclosure relates to tissue ablation systems and methods, particularly to prevent or minimize risk of skin bums associated with dispersive electrodes.

[0003] Tissue ablation can include the removal or destruction of a body part or tissue or its function. Tissue ablation can be a procedure doctors use to destroy abnormal tissue that can be present in many conditions. For example, a doctor might use an ablation procedure to destroy a small amount of heart tissue that is causing irregular heartbeats or to treat tumors in the lung, breast, thyroid, liver, uterus or other areas of the body.

[0004] Tissue can be ablated by the delivery of ablative energy. The ablative energy may comprise electrical energy (e.g., radiofrequency energy', laser energy, or micro wave energy), freezing energy (e.g., cryo energy ), ultrasound energy, high intensity- focused ultrasound (HIFU), or radiation. Preferably, the ablative energy- can comprise electrical energy, such as radiofrequency (RF) energy.

[0005] Electrical ablative energy-, such as RF energy', can be delivered to tissue using a treatment needle. Preferably, the treatment needle comprises at least one electrically conductive electrode that delivers electrical ablative energy. Electrical ablative energy can be delivered to target tissue from an electrical power source (e.g.. an RF generator) in multiple ways, including in a bipolar fashion and/or in a monopolar fashion. A bipolar configuration can include two adjacent electrodes. A monopolar configuration can include a single electrode and at least one distant dispersive electrode, which, in some embodiments, can be affixed to the back or to the thigh.

[0006] When electrical ablative energy (e.g., RF energy) is delivered in a bipolar fashion, the electrical ablative energy is delivered between two adjacent electrodes (e.g., needles). The two adjacent electrodes can be placed in proximity to the target tissue. In such a bipolar configuration, the electrical ablative energy flows from the power source (e.g., RF generator), to one of the two adjacent electrodes, through the target tissue, then to the second of the two adjacent electrodes before returning to the power source to complete the circuit.

[0007] When electrical ablative energy (e.g., RF energy) is delivered in a monopolar fashion, the electrical ablative energy can be delivered to a single electrode, electrode array or “active electrode” (e.g., a single needle or an array of needles), and at least one dispersive electrode can be placed distant from the target tissue, for example to the thigh or back. The dispersive electrode can serve as the grounding electrode or neutral electrode, providing the return path for electrical ablative energy (e.g.. RF energy) that is delivered from the electrical power source (e.g., RF generator). In some embodiments, more than one dispersive electrode can be used. The active electrode, e.g., a needle array, can be placed in proximity to the target tissue. In such a monopolar configuration, the electrical ablative energy flows from the power source (e.g.. RF generator), to the active electrode, through the target tissue, then to the distant dispersive electrode before returning to the power source.

SUMMARY

[0008] The embodiments disclosed herein each have several aspects no single one of which is solely responsible for the disclosure’s desirable attributes. Without limiting the scope of this disclosure, its more prominent features will now be briefly discussed. After considering this discussion, and particularly after reading the section entitled “Detailed Description,” one will understand how the features of the embodiments described herein provide advantages over existing systems, devices, and methods.

[0009] The present disclosure relates to medical systems, devices, and methods, particularly for but not limited to uterine fibroid ablation. Embodiments of the present disclosure provide systems and methods to prevent or minimize risk of skin bums by dispersive electrodes. Such systems and methods can prevent or minimize such risk by monitoring properties of dispersive electrodes or portions thereof, and responding to such monitoring.

[0010] In certain aspects, the present disclosure relates to monopolar tissue ablation systems and methods, particularly to prevent or minimize risk of skin bums associated with using one or more dispersive electrodes. Embodiments of the present disclosure provide a hardware processor in electrical communication with the one or more dispersive electrodes. In some embodiments, the hardware processor can be configured to monitor properties (e.g., electrical properties) of the one or more dispersive electrodes. In some embodiments, the hardware processor can prevent or minimize risk of skin bums associated with using one or more dispersive electrodes by being responsive to the monitored properties if threshold conditions are satisfied. In some embodiments, if threshold conditions are satisfied, the hardware processor can respond by, for example, alerting a user, reducing the power used by the tissue ablation system, and/or turning off the power used by the tissue ablation system.

[0011] There is provided in accordance with one aspect of the invention, a tissue ablation system. The tissue ablation system can be configured to reduce a risk of bums on a patient during an ablation procedure. The tissue ablation system can include a radio frequency (RF) generator configured to generate ablation energy. The tissue ablation system can include an ablation device configured to be electrically coupled with the RF generator and configured to receive the ablation energy from the RF generator. The ablation device can include an active electrode configured to deliver the ablation energy originating from the RF generator to a target tissue of the patient to ablate the target tissue. The tissue ablation system can include a plurality of dispersive electrode portions configured to be coupled to the skin of the patient, wherein each dispersive electrode portion is configured to be coupled to the skin of the patient at a location not overlapping with any other dispersive electrode portion. Each dispersive electrode portion can be configured to conduct an electrical current between the skin of the patient where the dispersive electrode portion is coupled and the RF generator. The RF generator can include one or more hardware processors. The one or more hardware processors can be configured to monitor an initial resistance between each of the dispersive electrode portions at a beginning of an ablation, monitor a real-time resistance between each of the dispersive electrode portions during the ablation, and/or monitor a total ablation energy provided from the RF generator to the ablation device. The one or more hardware processors can also be configured to terminate the ablation in response to determining that the real-time resistance satisfies a condition relative to the initial resistance, and the total ablation energy provided from the RF generator to the ablation device exceeds an energy threshold.

[0012] In the above tissue ablation system or in other implementations as described herein, one or more of the following features can also be provided. In some embodiments, the plurality' of dispersive electrode portions includes a plurality' of dispersive electrodes. In some embodiments, the plurality of dispersive electrode portions includes one split dispersive electrode. In some embodiments, the one or more hardware processors are configured to monitor a real-time temperature of at least one dispersive electrode portion. In some embodiments, the plurality of dispersive electrode portions includes a first electrode and a second electrode, wherein the first electrode is configured to be coupled to the skin of the patient at a first location and configured to conduct a first electrical current between the skin of the patient at the first location and the RF generator, and wherein the second electrode is configured to be coupled to the skin of the patient at a second location and configured to conduct a second electncal current between the skin of the patient at the second location and the RF generator. In some embodiments, the one or more hardware processors are configured to determine that the real-time resistance satisfies the condition if a difference between the real-time resistance and initial resistance exceeds a resistance threshold. In some embodiments, the resistance threshold is about 4.5 Ohms. In some embodiments, the one or more hardware processors are configured to determine that the real-time resistance satisfies the condition if a ratio of the real-time resistance to the initial resistance exceeds a resistance threshold. In some embodiments, the one or more hardware processors are configured to determine that the real-time resistance satisfies the condition if the following ratio exceeds a resistance threshold wherein R(t) is the real-time resistance, and w erein bi is the initial resistance between each of the dispersive electrode portions at a beginning of an ablation. In some embodiments, the resistance threshold is about 3%. In some embodiments, the energy threshold is between 30kJ and 50kJ. In some embodiments, the total ablation energy comprises a total amount of ablation energy provided since the beginning of the ablation. In some embodiments, the one or more hardware processors are configured to terminate the ablation in response to determining that an expected ablation energy exceeds an energy threshold. In some embodiments, the one or more hardware processors are configured to allow the ablation to continue in response to determining that an expected ablation energy is within an energy threshold. In some embodiments, the target tissue is a uterine fibroid, and wherein the active electrode is configured to deliver the ablation energy to the uterine fibroid. In some embodiments, the active electrode is configured to deliver the ablation energy to the uterine fibroid transcervically.

[0013] There is provided in accordance with another aspect of the invention, a computer-implemented method performed under control of one or more hardware processors executing program instructions. The computer-implemented method includes monitoring an initial resistance at a beginning of an ablation between a first dispersive electrode portion coupled to the skin of the patient at a first location and a second dispersive electrode portion coupled to the skin of the patient at a second location. The computer- implemented method includes monitoring a real-time resistance between the first dispersive electrode portion and the second dispersive electrode portion during the ablation. The computer-implemented method includes monitoring a total ablation energy provided from the RF generator to the ablation device. And the computer-implemented method includes terminating the ablation in response to determining that the real-time resistance satisfies a condition relative to the initial resistance, and the total ablation energy provided from the RF generator to the ablation device exceeds an energy' threshold.

[0014] There is provided in accordance with another aspect of the invention, a tissue ablation system. The tissue ablation system can be configured to reduce a risk of bums on a patient during an ablation procedure. The tissue ablation system can include a radio frequency (RF) generator configured to generate ablation energy. The tissue ablation system can include an ablation device configured to be electrically coupled with the RF generator and configured to receive the ablation energy from the RF generator. The ablation device can include an active electrode configured to deliver the ablation energy originating from the RF generator to a target tissue of the patient to ablate the target tissue. The tissue ablation system can include a plurality' of dispersive electrode portions configured to be coupled to the skin of the patient, wherein each dispersive electrode portion is configured to be coupled to the skin of the patient at a location not overlapping with any other dispersive electrode portion. Each dispersive electrode portion can be configured to conduct an electrical current between the skin of the patient where the dispersive electrode portion is coupled and the RF generator. The RF generator can include one or more hardware processors. The one or more hardware processors can be configured to monitor the electrical cunent conducted from each dispersive electrode portion during an ablation. The one or more hardware processors can be configured to monitor a total ablation energy provided from the RF generator to the ablation device. The one or more hardware processors can terminate the ablation in response to determining that the electrical current conducted from any dispersive electrode portion exceeds the electrical current conducted by any other dispersive electrode portion by more than a current threshold, and the total ablation energy provided from the RF generator to the ablation device exceeds an energy threshold.

[0015] In the above tissue ablation system or in other implementations as described herein, one or more of the following features can also be provided. In some embodiments, the plurality of dispersive electrode portions includes a plurality of dispersive electrodes. In some embodiments, the plurality of dispersive electrode portions includes one split dispersive electrode. In some embodiments, the one or more hardware processors are configured to monitor a real-time temperature of at least one dispersive electrode portion. In some embodiments, the plurality of dispersive electrode portions includes a first electrode and a second electrode, wherein the first electrode is configured to be coupled to the skin of the patient at a first location and configured to conduct a first electrical current between the skin of the patient at the first location and the RF generator, and wherein the second electrode is configured to be coupled to the skin of the patient at a second location and configured to conduct a second electrical current between the skin of the patient at the second location and the RF generator. In some embodiments, the one or more hardware processors are configured to determine that first electrical current exceeds the second electrical current by more than the current threshold if a ratio of the first electrical current to the second electrical current exceeds the current threshold. In some embodiments, the one or more hardware processors are configured to determine that first electrical current exceeds the second electrical current by more than the current threshold if a ratio of a square of the first electrical current to a square of the second electrical current exceeds the current threshold. In some embodiments, the current threshold is 1.35. In some embodiments, the energy threshold is between 40kJ and 60kJ. In some embodiments, the total ablation energy comprises a total amount of ablation energy’ provided since the beginning of the ablation. In some embodiments, the one or more hardware processors are configured to terminate the ablation in response to determining that an expected ablation energy exceeds an expected energy threshold. In some embodiments, the one or more hardware processors are configured to allow the ablation to continue in response to determining that an expected ablation energy is within an expected energy' threshold. In some embodiments, the target tissue is a uterine fibroid, and wherein the active electrode is configured to deliver the ablation energy to the uterine fibroid. In some embodiments, the active electrode is configured to deliver the ablation energy to the uterine fibroid trans cervically. [0016] There is provided in accordance with another aspect of the invention, a computer-implemented method performed under control of one or more hardware processors executing program instructions. The computer-implemented method includes monitoring a first electrical current conducted from a first dispersive electrode portion coupled to a patient at a first location during an ablation. The computer-implemented method includes monitoring a second electrical current conducted from a second dispersive electrode portion coupled to the patient at a second location during the ablation. The computer-implemented method includes monitoring a total ablation energy provided from the RF generator to the ablation device. The computer-implemented method also includes terminating the ablation in response to determining that the first electrical current exceeds the second electrical current by more than a current threshold, and the total ablation energy provided from the RF generator to the ablation device exceeds an energy threshold.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The novel features of the present disclosure are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present disclosure will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which:

[0018] FIGURE 1 shows a monopolar tissue ablation system, configured to ablate uterine fibroids, according to embodiments disclosed herein.

[0019] FIGURE 2 shows a block diagram of an RF generator of a tissue ablation system, according to embodiments disclosed herein.

[0020] FIGURE 3 shows a flow diagram of a mechanism for preventing or minimizing risk of skin bums at dispersive pads, according to embodiments disclosed herein.

[0021] FIGURE 4 shows a flow diagram of a mechanism for preventing or minimizing risk of skin bums at dispersive pads, according to embodiments disclosed herein.

[0022] FIGURE 5 shows a flow diagram of a mechanism for preventing or minimizing risk of skin bums at dispersive pads, according to embodiments disclosed herein. DETAILED DESCRIPTION

Tissue Ablation Examples

[0023] Tissue ablation has a wide variety of medical applications. As noted elsewhere herein, tissue ablation can be used to treat cardiac arrythmia and/or to destroy abnormal tissue. Such abnormal tissue can include, but is not limited to, benign tumors (e.g., fibroids) or metastatic tumors. Such abnormal tissue can be located in various regions of the body, including but not limited to tissues in and/or around the heart, lungs, breast, thyroid, liver, kidneys, bones, adrenal glands, endometrium and/or uterus.

[0024] Unless expressly stated otherwise, all principles and embodiments disclosed herein are not limited to ablation of only one specific type of tissue or to tissue in and/or around only one organ or region of the body. Instead, the skilled artisan will appreciate that the principles and embodiments disclosed herein can be applied to the ablation of different types of tissues in various regions of the body. Nonetheless, for purposes of explanation and clarity, a nonlimiting example of uterine fibroid ablation is illustrated in Figure 1 and discussed herein.

[0025] Uterine fibroids are benign tumors of the uterine myometria (i.e., muscle) and are the most common tumor of the female pelvis. Fibroid tumors affect up to 30% of women of childbearing age and can cause significant symptoms such as discomfort, pelvic pain, mennorhagia, pressure, anemia, compression, infertility and miscarriage. Fibroids may be located in the myometrium (i.e., intramural), adjacent to the endometrium (i.e., submucosal), or in the outer layer of the uterus (i.e.. subserosal). Most commonly fibroids are a smooth muscle overgrowth that arise intramurally and can grow to be several centimeters in diameter.

[0026] Uterine fibroids can be reduced and/or eliminated by ablation, for example, with electrical energy (e.g., RF energy). Electrical energy (e.g., RF energy) can be delivered to uterine fibroids from an electrical power source (e.g., an RF generator) in electrical communication with an active electrode, such as a needle or an array of needles. The active electrode (e.g., a needle or array of needles) can be transcervically delivered in proximity to a fibroid (e.g., through the vagina, through the cervix, and into/around the uterine cavity). The active electrode (e.g., a needle or array of needles) can be laparoscopically delivered into proximity to a fibroid. The power source can be configured to deliver monopolar or bipolar electrical energy, as described above. The delivery of the active electrode into the uterine cavity and/or into the fibroid can be aided with medical imaging, such as ultrasound imaging. An ultrasound transducer can be coupled to the active electrode. One example of a treatment device is the Sonata® treatment device available from Gynesonics, Inc. of Redwood City, CA.

[0027] Embodiments of the present disclosure are applicable to the Sonata® System available from Gynesonics, Inc. of Redwood City, CA and like systems, devices, and methods described in the following co-assigned U.S. Patents and Patent Applications, which are incorporated herein by reference in their entireties: U.S. Patent Numbers 7,918,795; 9,357.977; 7,815,571; 7,874,986; 10.058,342; 8,088,072; 8,206,300;

9,861,336; 8.992,427; 11,219.483; and 11,612.431; and U.S. Patent Publication Number 2019/0350648.

[0028] Figure 1 shows a tissue ablation system configured for ablation of uterine fibroids. The tissue ablation system comprises multiple components that complete an electrical circuit. The tissue ablation system shown in Figure 1 has a monopolar configuration. The tissue ablation system comprises an RF generator, an ablation device, and dispersive electrode pads. The RF generator is an electrical power source. The RF generator is in electrical communication with the ablation device. The ablation device shown in Figure 1 is inserted transcervically into the uterus of a patient. The uterus shown in Figure 1 has fibroids. The distal portion of the ablation device (the portion of the ablation device inside the uterus) comprises an active electrode. The active electrode is placed in proximity to (e.g., within) the fibroid to be ablated. The tissue ablation system shown in Figure 1 shows two dispersive electrode pads, which sen e as dispersive electrodes in the displayed monopolar configuration. Dispersive electrodes or dispersive pads can interchangeably be referred to as grounding electrodes, neutral electrodes, or return electrodes. The two dispersive pads shown in Figure 1 are shown as affixed to the anterior thighs of the patient. The dispersive pads are in electrical communication with the RF generator. The electrical signal (e.g., RF signal) is delivered in a circuit: from the RF generator to the active electrode of the ablation device, through the target tissue (e.g., a fibroid) to the dispersive pads, then back to the RF generator.

[0029] The tissue ablation system shown in Figure 1 shows two dispersive electrode pads, which may also be considered dispersive electrode portions. In some embodiments, a tissue ablation system comprises one dispersive electrode. In some embodiments, one dispersive electrode can be split and comprise multiple dispersive electrode portions (e.g., multiple dispersive electrode pads). In some embodiments, atissue ablation system comprises more than two or more dispersive electrodes, and each of the dispersive electrodes can comprise one or more dispersive electrode portions (e.g., multiple dispersive electrode pads). In some embodiments, a plurality of dispersive electrode portions can be coupled to the skin of a patient in a plurality of non-overlapping locations.

[0030] In some embodiments, a dispersive electrode pad can comprise at least one thermocouple. A thermocouple can measure the temperature at a location on the dispersive electrode pad. Information from a thermocouple can be used to prevent or minimize risk of skin bums.

Skin Bum Prevention Algorithm

[0031] One complication of monopolar electrical ablation (e.g., monopolar RF ablation) can include thermal skin injuries (e.g., bums) near the dispersive electrode(s). The incidence of thermal skin injuries near the dispersive electrode(s) can be reduced by monitoring the properties (e.g., the electrical and/or mechanical properties) of the dispersive electrodes.

[0032] Figure 2 is a block diagram illustrating example radio frequency (RF) generator 200 which can include similar structural and/or operational features as example RF generator shown and/or described in Figure 1. The RF generator 200 can include a hardware processor 201, a storage unit 203, a display unit 205, an energy generator 207, a user input unit 209, a speaker 211, an electrode input 213, an energy' output 215, and a power source 217.

[0033] The hardware processor 201 can comprise one or more integrated circuits. The hardware processor 201 may comprise and/or have access to memory. The hardware processor 201 may comprise and/or be embodied as one or more chips, controllers such as microcontrollers (MCUs), and/or microprocessors (MPUs). The hardware processor 201 may comprise a central processing unit (CPU). In some implementations, the hardware processor 201 may be embodied as a system-on-a-chip (SoC). The hardware processor 201 may be configured to implement an operating system which may allow multiple processes to execute simultaneously. The hardware processor 201 can be configured to execute program instructions to cause the RF generator 200 (or components thereof) to perform one or more operations. The hardware processor 201 can be configured, among other things, to process data, execute instructions to perform one or more functions, and/or control the operation of the RF generator 200 or components thereof. For example, the hardware processor 201 can process data originating from dispersive electrodes and received via electrode input 213 and can execute instructions to perform functions related to tissue ablation based on the data. In some implementations, the hardware processor 201 may be remote to the RF generator 200.

[0034] The hardware processor 201 can be configured to monitor various properties of the dispersive electrodes. As one example, the hardware processor 201 can monitor whether the dispersive electrode pad(s) is/are in sufficient contact with the patient's skin. As another example, the hardware processor 201 can monitor whether the dispersive pad(s) is/are connected to the RF generator (e.g.. the electrode input 213 of the RF generator 200). Moreover, the hardware processor 201 can be configured to be responsive to one or more triggering events. A triggering event can occur when a property⁷ being monitored by the hardware processor 201 exceeds a trigger threshold. The hardware processor 201 can be configured to respond to certain triggering events in certain ways. For example, a more severe triggering event may call for a more urgent response from the hardware processor 201 (e.g., stopping the tissue ablation procedure), while a less severe triggering event may call for a less urgent response from the hardware processor 201 (e.g., a warning signal to the user).

[0035] A trigger threshold, when exceeded, can lead to a triggering event. A trigger threshold can be associated with any monitored property. A trigger threshold can be associated with a property⁷ being directly measured, such as electrical resistance, electrical current, duration, etc. A trigger threshold can be associated with a property that is indirectly monitored (e.g., internally calculated), such as total energy delivered, expected time remaining for the present ablation, etc. A trigger threshold can be pre-programmed. A trigger threshold can be retrieved from a look-up table. A trigger threshold can be entered by a user. A trigger threshold can be set during calibration. A trigger threshold can be derived by the system, based, for example, on other information available to the system, which can include, e.g., patient age, patient weight, fibroid size, etc.

[0036] The storage unit 203 can include any computer readable storage medium and/or device (or collection of data storage mediums and/or devices), including, but not limited to, one or more memory devices that store data, including without limitation, dynamic and/or static random-access memory⁷ (RAM), programmable read-only memory (PROM), erasable programmable read-only^ memory (EPROM), electrically erasable programmable read-only memory⁷ (EEPROM), optical disks (e.g., CD-ROM, DVD-ROM, etc.), magnetic disks (e.g., hard disks, floppy disks, etc ), emory circuits (e.g., solid state drives, random-access memory' (RAM), etc.), and/or the like. The storage unit 203 can store data including resistance measurements originating from dispersive electrodes, for example. The storage unit 203 can store program instructions that when executed by the hardware processor 201 cause the RF generator 200 to perform one or more operations.

[0037] The display unit 205 can display user interfaces, such as any of the example user interfaces, or aspects thereof, that are shown and/or described herein. The display unit 205 can include an LED screen, an LCD screen, an OLED screen, a QLED screen, a plasma display screen, a quantum dot display screen, or the like. The display unit 205 may be responsive to touch. For example, the display unit 205 may comprise a touchscreen such as a resistive touchscreen, a capacitive touchscreen, an infrared touchscreen, a surface acoustic wave touchscreen, or the like. The display unit 205 can display user interfaces, including notifications or alerts, based on data originating from hardware processor 201 and/or storage unit 203. The hardware processor 201 can generate user interface data for rendering interactive graphical user interfaces via the display unit 205. The hardw are processors 201 can cause the display unit 205 to notify the user based on one or more conditions to reduce or minimize the risk of burning the patient with dispersive electrodes. Types of notifications can include but are not limited to, for example, a display message, instructions, warnings, cautionary statements, etc.

[0038] The energy generator 207 can generate energy' to provide to an ablation device connectable to the RF generator 200 (e.g., via the energy output 215). The energy generator 207 can generate radio frequency energy. The energy generator 207 can generate energy automatically or in response to a user input (e.g., via user input unit 209). The hardware processor 201 can control operation of the energy' generator 207 including controlling an amount of energy generation and/or terminating energy' generation.

[0039] The user input unit 209 can include an actuator that can be actuated by a user. The hardware processor 201 can monitor a state of the user input unit 209 and can generate instruction to control operation of the RF generator 200 based on actuation of the user input unit 209. The user input unit 209 can be disposed on a housing of the RF generator 200. The user input unit 209 can be connectable to the RF generator 200 (e.g., via a wire or cable). The user input unit 209 can be, for example, a button, a lever, a dial, or a pedal. The user input unit 209 can be operable by a finger or hand of a user. The user input unit 209 can be operable by a foot of a user. The user input unit 209 can be physically actuated to change a physical state (e g., physically moved between positions). The user input unit 209 can be an interactive graphical user interface operable by a user via a display screen responsive to touch.

[0040] The speaker 211 can emit audio including notifications or alerts. The audio can include verbal instructions or suggestions. The audio can include one or more sounds, beeps, tones, or the like. The hardware processor 201 can cause the speaker 211 to emit audio based on one or more conditions to reduce or minimize the risk of burning the patient with dispersive electrodes.

[0041] The electrode input 213 can include one or more ports configured to mechanically and/or electrically couple the RF generator 200 to one or more dispersive electrodes. The electrode input 213 can receive measurements of electrical current from the dispersive electrodes. The hardware processors 201 can monitor dispersive electrodes, such as current and/or resistance based on information received from the electrode input 213. In embodiments in which a dispersive electrode pad comprises at least one thermocouple, the hardware processors 201 can monitor temperature information received from the electrode input 213.

[0042] The energy output 215 can connect the RF generator 200 to an ablation device. The energy output 215 can include a port configured to mechanically and/or electrically couple the RF generator 200 to an ablation device. The energy output 215 can provide power from the RF generator 200 (e.g., from the energy' generator 207) to an ablation device.

[0043] The power source 217 can provide power for components of the RF generator 200. The power source 217 can include a battery. In some implementations, the power source 217 may be external to the RF generator 200. For example, the RF generator 200 can include or can be configured to connect to a cable which can itself connect to an external power source to provide power to the RF generator 200.

[0044] Figure 3 is a flowchart illustrating an example process 300 of monitoring dispersive electrode resistance during ablation to minimize undesirable heating of the dispersive electrodes. This process, in full or parts, can be executed by one or more hardware processors, whether they are associated with a singular or multiple computing devices, and even devices in remote or wireless communication. By way of example, the one or more hardware processors executing process 300 can be associated with any of the example RF generators shown and/or described herein. The implementations of this process may vary and can involve modifications like omiting blocks, adding blocks, and/or rearranging the order of execution of the blocks. Process 300 serves as an example and is not intended to restrict the present disclosure.

[0045] At block 301 a computing device (e.g., one or more hardware processors of a computing device executing program instructions) can monitor resistance between dispersive electrodes when the electrodes are placed on the tissue of a patient (e.g., on a patient's legs or back). Dispersive electrodes can be placed on the tissue of a patient before ablation. This resistance can be referred to as bO. The resistance bO can be a moving average of a plurality of resistance measurements over a period of time, such as about 1 second, about 2 seconds, about 3 seconds, about 4 seconds, about 5 seconds, about 6 seconds, about 7 seconds, about 8 seconds, or more. Monitoring resistance upon initial electrode placement can ensure that the dispersive electrodes have been properly placed on the tissue of patient prior to ablation.

[0046] At block 303 the computing device can monitor real-time resistance between dispersive electrodes. This resistance can be referred to as R(t) and can be a moving average of a plurality of resistance measurements over a period of time, such as about 1 second, about 2 seconds, about 3 seconds, about 4 seconds, about 5 seconds, about 6 seconds, about 7 seconds, about 8 seconds, or more. The computing device can monitor R(t) prior to any ablations. The real-time resistance R(t) can depend on a number of factors including how dispersive electrodes are placed on the patient.

[0047] At decision block 305 the computing device can determine whether the real-time resistance R(t) satisfies a condition. The condition can be relative to the resistance bO. For example, the condition can be satisfied if a difference (e.g., an absolute difference) between R(t) and bO exceeds a resistance threshold. As another example, the condition can be satisfied if a ratio of R(t) to bO exceeds a resistance threshold. Monitoring the real-time resistance between electrodes relative to the initial resistance when the dispersive electrodes are first placed on the patient can indicate how the resistance has changed since placing the dispersive electrodes. Significant changes in resistance, whether increases or decreases, can correspond to changes in the amount of current flowing from the electrodes which can correspond to increases in temperature at the electrodes which may risk burning the patient.

[0048] In some implementations, the condition can be satisfied if ' ^R(~^_o ^b° ' > X, where X can be equal to any value between 1% and 10%, between 1% and 8%, between 1% and 6%, between 2% and 5%, between 2% and 4%, or about 3%. If R(t) satisfies the condition relative to bO at decision block 305, the process 300 can proceed to block 307. If R(t) does not satisfy the condition relative to bO at decision block 305, the process 300 can proceed to decision block 309.

[0049] At block 307 the computing device can generate a notification which can indicate to a user to adjust placement of one or more of the dispersive pads on the patient. The notification can include visual indicators such as LED illumination and/or visual indicia displayed on a display screen. The notification can include audio generated from a speaker and can include verbal commands.

[0050] At decision block 309 the computing device can determine whether a time since measuring bO exceeds a time threshold. The time threshold can be between <7i and di , such as between 60 seconds and 180 second, between 90 seconds and 150 seconds, or about 120 seconds. If the time has exceeded the time threshold at block 309, the process 300 can proceed to block 311 where the process 300 can terminate. If the time has not exceeded the time threshold at block 309, the process 300 can return to block 303.

[0051] Figure 4 is a flowchart illustrating an example process 400 of monitoring dispersive electrode resistance during ablation to minimize undesirable heating of the dispersive electrodes. This process, in full or parts, can be executed by one or more hardware processors, whether they are associated with a singular or multiple computing devices, and even devices in remote or wireless communication. By way of example, the one or more hardware processors executing process 400 can be associated with any of the example RF generators shown and/or described herein. The implementations of this process may vary and can involve modifications like omitting blocks, adding blocks, and/or rearranging the order of execution of the blocks. Process 400 serves as an example and is not intended to restrict the present disclosure.

[0052] In some embodiments, dispersive electrode resistance is monitored by measuring a real-time resistance during an ablation, and comparing the real-time resistance to a baseline resistance measured before the ablation began or during the first few seconds of the ablation. The baseline resistance can include measurements immediately preceding providing energy to an ablation device, at the time of providing energy to an ablation device, and/or while providing energy to the ablation device immediately after commencing to provide the energy. A new baseline resistance can be measured for each ablation. For example, a first baseline (bl) can be measured for the first ablation. A second baseline (b2) can be measured for a second ablation. And more generally, an i* baseline (bi) can be measured for an i^th ablation, where i > 1. An ablation can refer to any period of time wherein energy is provided to an ablation device. For example, while ablating one or more fibroids, an RF generator can provide energy to an ablation device during one or more ablations. The number of ablations required to ablate a fibroid may vary with characteristics of the fibroid, such as size. For example, multiple ablations may be required to ablate a single large fibroid. This baseline resistance (bl and/or bi) defines a Contact Quality Monitor (CQM). CQM can be a moving average of a plurality of resistance measurements over a period of time, such as about 1 second, about 2 seconds, about 3 seconds, about 4 seconds, about 5 seconds, about 6 seconds, about 7 seconds, about 8 seconds, or more.

[0053] At block 401 a computing device (e.g., one or more hardware processors of a computing device executing program instructions) can monitor a baseline resistance between dispersive electrodes at the beginning of a first ablation (bl).

[0054] At block 403 the computing device can optionally monitor a baseline resistance between dispersive electrodes at the beginning of an i^th ablation (bi), where i > 1.

[0055] At block 405 the computing device can monitor real-time resistance between dispersive electrodes. This resistance can be referred to as R(t) and can be a moving average of a plurality of resistance measurements over a period of time, such as about 1 second, about 2 seconds, about 3 seconds, about 4 seconds, about 5 seconds, about 6 seconds, about 7 seconds, about 8 seconds, or more. The computing device can monitor R(t) during one or more ablations, such as during ablations corresponding to bl and/or bi. The computing device can monitor R(t) between ablations.

[0056] At block 407 the computing device can monitor energy provided to an ablation device (e.g., from an RF generator). The computing device can monitor a cumulative energy provided to the ablation device during a period of time, during a single ablation, and/or during multiple ablations. For example, an RF generator can provide between 40kJ and 70kJ of energy over the course of an ablation. In some implementations, the computing device can monitor a rate at which energy' is provided to the ablation device (e.g., in Watts). Real time resistance R(t) can depend on a number of factors including how dispersive electrodes are placed on a patient, the amount of energy provided during an ablation, temperature at the dispersive electrodes, etc. and thus may change during an ablation procedure. [0057] At decision block 409 the computing device can determine whether the real-time resistance R(t) satisfies a condition. The condition can be relative to the resistance bl. For example, the condition can be satisfied if a difference between R(t) and bl exceeds a resistance threshold. As another example, the condition can be satisfied if a ratio of R(t) to b 1 exceeds a resistance threshold. Monitoring the real-time resistance between electrodes relative to the resistance at the beginning of the first ablation can indicate how the resistance has changed since commencing the first ablation. Significant changes in resistance, whether increases or decreases, can correspond to changes in the amount of current flowing from the electrodes which can correspond to increases in temperature at the electrodes which may risk burning the patient.

[0058] In some implementations, the condition can be satisfied if > x, where X can be equal to any value between 1% and 10%, between 1% and 8%, between 1% and 6%, between 2% and 5%, between 2% and 4%, or about 3%. Increases or decreases in resistance of more than about 3% since commencing the first ablation can correspond to temperature increases at the dispersive electrodes posing a risk of bums to the patient.

[0059] In some implementations, the condition can be satisfied if R(t) - bl > X, where X can be equal to any value between xi and X2, such as between 3 Ohms and 6 Ohms, between 3.5 Ohms and 5.5 Ohms, between 4 Ohms and 5 Ohms, or about 4.5 Ohms. Increases in resistance of more than about 4.5 Ohms since commencing the first ablation can correspond to temperature increases at the dispersive electrodes posing a risk of bums to the patient.

[0060] In some implementations, the condition can be satisfied if bl - R(t) > X, where X can be equal to any value between xi and X2, such as between 1 Ohms and 4 Ohms, between 1.5 Ohms and 3.5 Ohms, between 2 Ohms and 3 Ohms, or about 2.5 Ohms. Decreases in resistance of more than about 2.5 Ohms since commencing the first ablation can correspond to temperature increases at the dispersive electrodes posing a risk of bums to the patient.

[0061] In some implementations, the condition can be satisfied if |R(t) - bl | > X, where X is large enough to indicate a more urgent risk of skin bum. In such implementations, X can be equal to any value between xi and X2, such as between 3 Ohms and 10 Ohms, between 4 Ohms and 7 Ohms, between 4 Ohms and 6 Ohms, or about 5 Ohms. If the condition is satisfied, process 400 can bypass one or more intermediate threshold tests and proceed directly to block 417. [0062] In some implementations, the condition can be relative to various other parameters. In some implementations, the parameters can be measured in various ways. In some embodiments, the parameter can be measured as an absolute value. In some embodiments, the parameter can be measured as a value imbalance. In some embodiments, the parameter can be measured as a shift ratio. In some embodiments, the parameter can be measured as velocity of change over time (e.g., the rate of change of resistance over time). In some embodiments, the parameter can be measured as a positive shift value from each established level. In some embodiments, the parameter can be measured as a negative shift value from each established level. In some embodiments, the parameter can be measured as total integrated delivered power (e.g., RF power). In some embodiments, the condition can be relative to a heat factor ratio (HFR) value. An HFR quantifies a specific disparity between two currents, such as a first current (II) flowing from a first dispersive electrode pad and a second current (12) flowing from a second dispersive electrode pad, where II is equal to or greater than 12 by convention. Disparities between II and 12 can correspond to increases in temperature at a dispersive electrode that can pose bum risks to the patient. The HFR is defined as the quantity of (~)² ■ By way of a first example, if the current flowing from both dispersive electrode pads is equal, the HFR is 1. By way of a second example, if Il is 20% greater than 12, the HFR is (~)²- ^or 1-44. In some embodiments, the parameter can be measured as a rolling average. In some embodiments, the parameter can be measured as a sliding window of a property, such as minimum, maximum, upward slope, downward slope, and area under the curve. In some embodiments, the parameter can be measured as total data points.

[0063] If R(t) satisfies the condition relative to bl at decision block 409, the process 400 can proceed to block 413. If R(t) does not satisly the condition relative to bl at decision block 409, the process 400 can proceed to decision block 41 1.

[0064] At decision block 411 the computing device can optionally determine whether the real-time resistance R(t) satisfies a condition. The condition can be relative to the resistance bi. For example, the condition can be satisfied if a difference between R(t) and bi exceeds a resistance threshold. As another example, the condition can be satisfied if a ratio of R(t) to bi exceeds a resistance ratio threshold. Monitoring the real-time resistance between electrodes relative to the resistance at the beginning of the i^th ablation can indicate how the resistance has changed since commencing the i* ablation. Significant changes in resistance, whether increases or decreases, can correspond to changes in the amount of current flowing from the electrodes which can correspond to increases in temperature at the electrodes which may risk burning the patient.

[0065] In some implementations, the condition can be satisfied if ' ^R(~^. ^bl ' > X, where X can be equal to any value between xi and X2, such as between 1% and 10%, between 1% and 8%, between 1% and 6%, between 2% and 5%. between 2% and 4%, or about 3%. Increases or decreases in resistance of more than about 3% since commencing the i^th ablation can correspond to temperature increases at the dispersive electrodes posing a risk of bums to the patient.

[0066] In some implementations, the condition can be satisfied if R(t) - bi > X, where X can be equal to any value between xi and 2, such as between 3 Ohms and 6 Ohms, between 3.5 Ohms and 5.5 Ohms, between 4 Ohms and 5 Ohms, or about 4.5 Ohms. Increases in resistance of more than about 4.5 Ohms since commencing the 1^th ablation can correspond to temperature increases at the dispersive electrodes posing a risk of bums to the patient.

[0067] In some implementations, the condition can be satisfied if bi - R(t) > X, where X can be equal to any value between xi and X2, such as between 1 Ohms and 4 Ohms, between 1.5 Ohms and 3.5 Ohms, between 2 Ohms and 3 Ohms, or about 2.5 Ohms. Decreases in resistance of more than about 2.5 Ohms since commencing the i^th ablation can correspond to temperature increases at the dispersive electrodes posing a risk of bums to the patient.

[0068] In some implementations, the condition can be satisfied if |R(t) - bi| > X, where X is large enough to indicate a more urgent risk of skin bum. In such implementations. X can be equal to any value between xi and X2, such as between 3 Ohms and 10 Ohms, between 4 Ohms and 7 Ohms, between 4 Ohms and 6 Ohms, or about 5 Ohms. If the condition is satisfied, process 400 can bypass one or more intermediate threshold tests and proceed directly to block 417.

[0069] In some implementations, the condition can be relative to various other parameters. In some implementations, the parameters can be measured in various ways. In some embodiments, the parameter can be measured as an absolute value. In some embodiments, the parameter can be measured as a value imbalance. In some embodiments, the parameter can be measured as a shift ratio. In some embodiments, the parameter can be measured as velocity of change over time (e.g., the rate of change of resistance over time). In some embodiments, the parameter can be measured as a positive shift value from each established level. In some embodiments, the parameter can be measured as a negative shift value from each established level. In some embodiments, the parameter can be measured as total integrated delivered power (e.g., RF power). In some embodiments, the condition can be relative to a heat factor ratio (HFR) value. In some embodiments, the parameter can be measured as a rolling average. In some embodiments, the parameter can be measured as a sliding window of a property, such as minimum, maximum, upward slope, downward slope, and area under the curve. In some embodiments, the parameter can be measured as total data points.

[0070] In some implementations, the computing device can determine whether R(t) satisfies the condition at block 411 based on an amount of energy provided to the ablation device, such as at every increment of lOkJ of energy⁷ provided to the ablation device. For example, during a first ablation, the process 400 can proceed without optional block 411. During a first ablation, the process 400 can be executed continuously. Executing process 400 continuously during a first ablation can help ensure a first ablation proceeds safely. During subsequent ablations, such as a second ablation (e.g., i = 2), the process 400 can be executed at an interval, rather than continuously. In some implementations, the process 400 can be executed at an interval of every E kilojoule (such as every 5kJ, every lOkJ, every 15kJ, etc.) of ablation. For example, the process 400 can be executed once after 40kJ of ablation, then again after 50kJ of ablation, then again after 60kJ of ablation, and so on.

[0071] During the optional execution of decision block 411, if R(t) satisfies the condition relative to bi, the process 400 can proceed to block 413. If R(t) does not satisfy the condition relative to bi at decision block 41 1 , the process 400 can return to decision block 405.

[0072] At block 413 the computing device can determine whether the energy provided to the ablation device exceeds an energy threshold. Temperature at a dispersive electrode can depend on energy provided during to an ablation device. The energy threshold can be between A'i and E2, such as between 30kJ and 50kJ, between 35kJ and 45kJ, or about 40kJ. Advantageously, monitoring changes in resistance in combination with amount of energy provided to an ablation device can provide a more accurate indication of the risk associated with bums of the patient’s skin. For example, the risk associated with bums of the patient’s skin can be lower if less ablative energy has been delivered to the patient, as compared to if more ablative energy⁷ has been delivered to the patient. If the energy⁷ exceeds re the energy threshold, the process 400 can proceed to block 415. If the energy does not exceed the energy threshold, the process 400 can return to block 405.

[0073] At block 415 the computing device can determine whether energy expected to be output to the ablation device exceeds an expected energy threshold. The expected energy threshold can be between E\ and Eb, such as between 50kJ and 70kJ, between 55kJ and 65kJ, or about 60kJ. The computing device can determine the expected energy output based on an estimated time remaining to complete an ablation. The computing device can determine the expected energy output based on a user input, such as an expected energy amount (e.g.. in kJ), an expected ablation time, and/or a size of a fibroid. The computing device can determine the expected energy output prior to commencing an ablation procedure and/or can dynamically update the expected energy output during an ablation procedure. If the amount of energy expected to complete an ablation is minimal (e.g., if the current ablation is nearly complete), completing the ablation may not pose a significant risk of bums to the patient. Advantageously, monitoring risk of bums to the patient during an ablation procedure based on at least expected energy output can improve controlling the ablation procedure. If the expected energy output exceeds the expected energy threshold, the process 400 can proceed to block 417. If the expected energy does not exceed the expected energy threshold, the process 400 can proceed to block 419.

[0074] At block 417 the computing device can terminate the ablation such as by causing the RF generator to stop providing energy to the ablation device.

[0075] At block 419 the computing device can allow the current ablation to finish such as by causing the RF generator to continue providing energy to the ablation device.

[0076] At block 421 the computing device can prevent subsequent ablations. Preventing subsequent ablation can be conditional. For example, the computing device can prevent subsequent ablations until a time period has expired, until a user input is received, until a user has replaced dispersive electrodes, until a user has acknowledged an alarm, etc.

[0077] At block 423 the computing device can generate a notification. The notification can include one or more auditory and/or visual indicators. For example, the computing device can generate an audio notification from a speaker. As another example, the computing device can cause a display screen to display a notification via a user interface. The notification can indicate a status of an ablation procedure (e.g., terminated, conditionally terminated, paused, continuing, etc.). The notification can indicate one or more reasons for an ablation procedure status (e.g., ablation terminated because of bum risk). The notification can indicate one or more actions for a user to take such as replacing dispersive electrodes on the patient, an amount of energy to user in future ablations, etc.

[0078] Figure 5 is a flowchart illustrating an example process 500 of monitoring dispersive electrode resistance during ablation to minimize undesirable heating of the dispersive electrodes. This process, in full or parts, can be executed by one or more hardware processors, whether they are associated with a singular or multiple computing devices, and even devices in remote or wireless communication. By way of example, the one or more hardware processors executing process 500 can be associated with any of the example RF generators shown and/or described herein. The implementations of this process may vary and can involve modifications like omitting blocks, adding blocks, and/or rearranging the order of execution of the blocks. Process 500 serves as an example and is not intended to restrict the present disclosure.

[0079] At block 501 a computing device (e.g., one or more hardware processors of a computing device executing program instructions) can monitor an electrical current from dispersive electrodes. The electrical current from a first dispersive electrode can be referred to as II and the electrical current from a second dispersive electrode can be referred to as 12. Electrical cunent from dispersive electrodes can vary depending on a number of factors including how the dispersive electrodes are placed on a patient. For example, a dispersive electrode that has less electrically conductive contact with a patient may conduct less electrical current than a dispersive electrode that has a greater electrically conductive contact with the patient. Dispersive electrodes that conduct greater amounts of electrical current can increase in temperature more than dispersive electrodes that conduct less electrical current. Accordingly, monitoring electrical current conducted from dispersive electrodes can indicate risk of bums to a patient.

[0080] At decision block 503 the computing device can determine whether II exceeds 12 by more than a current threshold. Disparities between II and 12 can correspond to increases in temperature at the dispersive electrodes that can pose bum risks to the patient. The current threshold can be based on a ratio of II to 12. In some implementations, the current threshold can be exceeded if > X, where X can be between xi and X2, such as between 1.0 and 2.0, between 1.2 and 1.7, between 1.3 and 1.5, between 1.3 and 1.4, or about 1.35. If the condition is satisfied at block 503. the process can proceed to block 505. If the condition is not satisfied at block 503, the process can return to block 501 . [0081] Alternatively, the current threshold can be based on a percentage difference between II and 12. In some implements, the current threshold can be exceeded if ^{|n 721} > X. where X can be equal to anv value between xi and X2. such as between 1% and 15%, between 2% and 10%, between 5% and 10%, between 6% and 9%, or about 8%. In some implementations, if X is large enough to indicate a more urgent risk of skin bum (e.g., about 8%), process 500 can skip blocks 505 and 507, and proceed directly to block 509.

[0082] At block 505 the computing device can determine whether the energy provided to the ablation device exceeds an energy’ threshold. Temperature at a dispersive electrode can depend on energy provided during to an ablation device. The energy threshold can be between £i and £2, such as between 40kJ and 60kJ, between 45kJ and 55kJ, or about 50kJ. Advantageously, monitoring changes in electrical current in combination with amount of energy provided to an ablation device can provide a more accurate indication of the risk associated with bums of the patient's skin. For example, the risk associated with bums of the patient’s skin can be lower if less ablative energy’ has been delivered to the patient, as compared to if more ablative energy has been delivered to the patient.. If the energy exceeds the energy’ threshold, the process 500 can proceed to block 507. If the energy does not exceed the energy threshold, the process 500 can return to block 501.

[0083] At block 507 the computing device can determine whether energy expected to be output to the ablation device exceeds an expected energy threshold. The expected energy’ threshold can be between £1 and £2, such as between 50kJ and 70kJ, between 55kJ and 65kJ, or about 60kJ. The computing device can determine the expected energy output based on an estimated time remaining to complete an ablation. The computing device can determine the expected energy output based on a user input, such as an expected energy’ amount (e.g., in kJ), an expected ablation time, and/or a size of a fibroid. The computing device can determine the expected energy output prior to commencing an ablation procedure and/or can dynamically update the expected energy output during an ablation procedure. If the amount of energy expected to complete an ablation is minimal (e.g., if the current ablation is nearly complete), completing the ablation may’ not pose a significant risk of bums to the patient. Advantageously, monitoring risk of bums to the patient during an ablation procedure based on at least expected energy output can improve controlling the ablation procedure. If the expected energy output exceeds the expected energy threshold, the process 500 can proceed to block 509. If the expected energy does not exceed the expected energy threshold, the process 500 can proceed to block 511.

[0084] At block 509 the computing device can terminate the ablation such as by causing the RF generator to stop providing energy to the ablation device.

[0085] At block 511 the computing device can allow the current ablation to finish such as by causing the RF generator to continue providing energy to the ablation device.

[0086] At block 513 the computing device can prevent subsequent ablations. Preventing subsequent ablation can be conditional. For example, the computing device can prevent subsequent ablations until a time period has expired, until a user input is received, until a user has replaced dispersive electrodes, until a user has acknowledged an alarm, etc.

[0087] At block 515 the computing device can generate a notification. The notification can include one or more auditory and/or visual indicators. For example, the computing device can generate an audio notification from a speaker. As another example, the computing device can cause a display screen to display a notification via a user interface. The notification can indicate a status of an ablation procedure (e.g., terminated, conditionally terminated, paused, continuing, etc.). The notification can indicate one or more reasons for an ablation procedure status (e.g., ablation terminated because of bum risk). The notification can indicate one or more actions for a user to take such as replacing dispersive electrodes on the patient, an amount of energy⁷ to user in future ablations, etc.

[0088] In some implementations, the systems and methods described above and as described in the Summary may not terminate the ablation upon determination of a specified condition. For example, step 417 of Figure 4 or step 509 of Figure 5 may be optional. Upon determination of a specified condition, the ablation may be allowed to be completed if an expected amount of energy is minimal, and/or subsequent ablations may be prevented. The systems and methods may also or alternatively provide a notification to a user as described above.

[0089] Although the example processes 400, 500 have been described above as only monitoring a resistance of dispersive electrodes or only monitoring an electrical current from dispersive electrodes during ablation to minimize undesirable heating of the dispersive electrodes, it should be appreciated that optional processes may concurrently monitor both the resistance of dispersive electrodes and the electrical current from dispersive electrodes during an ablative procedure to further minimize undesirable heating of the dispersive electrodes. For example, during a single ablation procedure, steps 401- 411 of the example process 400 can be performed in conjunction with steps 501-503 of the example process 500 to concurrently monitor both the resistance of the dispersive electrodes and the electrical current from the dispersive electrodes, and determine whether the conditions with respect to the resistance and the current have been satisfied. If either the condition with respect to the resistance or the condition with respect to the current has been satisfied, this optional example process can determine whether the total ablation energy delivered to the ablation device exceeds an energy threshold. If the expected energy output to the ablation devices exceeds an energy threshold the processor will terminate ablation and provide a notification based thereon (e.g., steps 413-423 or steps 505-515).

[0090] The foregoing description and examples has been set forth merely to illustrate the disclosure and are not intended as being limiting. Each of the disclosed aspects and embodiments of the present disclosure may be considered individually or in combination with other aspects, embodiments, and variations of the disclosure. In addition, unless otherwise specified, none of the steps of the methods of the present disclosure are confined to any particular order of performance. Modifications of the disclosed embodiments incorporating the spirit and substance of the disclosure may occur to persons skilled in the art and such modifications are within the scope of the present disclosure.

[0091] Terms of orientation used herein, such as “top,” “bottom,” “horizontal,” “vertical,” “longitudinal,” “lateral,” and “end” are used in the context of the illustrated embodiment. However, the present disclosure should not be limited to the illustrated orientation. Indeed, other orientations are possible and are within the scope of this disclosure. Terms relating to circular shapes as used herein, such as diameter or radius, should be understood not to require perfect circular structures, but rather should be applied to any suitable structure with a cross-sectional region that can be measured from side-to- side. Terms relating to shapes generally, such as “circular” or “cylindrical” or “semicircular” or “semi-cylindrical” or any related or similar terms, are not required to conform strictly to the mathematical definitions of circles or cylinders or other structures, but can encompass structures that are reasonably close approximations.

[0092] Conditional language used herein, such as, among others, “can,” “might.” “may,” “e.g.,” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that some embodiments include, while other embodiments do not include, certain features, elements, and/or states. Thus, such conditional language is not generally intended to imply that features, elements, blocks, and/or states are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without author input or prompting, whether these features, elements and/or states are included or are to be performed in any particular embodiment.

[0093] Conjunctive language, such as the phrase “at least one of X, Y, and Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to convey that an item. term. etc. may be either X, Y, or Z. Thus, such conjunctive language is not generally intended to imply that certain embodiments require the presence of at least one of X, at least one of Y, and at least one of Z.

[0094] The terms “approximately,'’ “about,” and “substantially” as used herein represent an amount close to the stated amount that still performs a desired function or achieves a desired result. For example, in some embodiments, as the context may dictate, the terms “approximately”, “about”, and “substantially” may refer to an amount that is within less than or equal to 10% of the stated amount. The term “generally” as used herein represents a value, amount, or characteristic that predominantly includes or tends toward a particular value, amount, or characteristic. As an example, in certain embodiments, as the context may dictate, the term “generally parallel” can refer to something that departs from exactly parallel by less than or equal to 20 degrees.

[0095] Where the term “about” is utilized before a range of two numerical values, this is intended to include a range between about the first value and about the second value, as well as a range from the first value specified to the second value specified.

[0096] Unless otherwise explicitly stated, articles such as “a” or “an” should generally be interpreted to include one or more described items. Accordingly, phrases such as “a device configured to” are intended to include one or more recited devices. Such one or more recited devices can be collectively configured to carry out the stated recitations. For example, “a processor configured to carry out recitations A, B, and C” can include a first processor configured to carry out recitation A working in conjunction with a second processor configured to carry out recitations B and C.

[0097] The terms “comprising.” “including,” “having.” and the like are synonymous and are used inclusively, in an open-ended fashion, and do not exclude additional elements, features, acts, operations, and so forth. Likewise, the terms “some,” “certain,” and the like are synonymous and are used in an open-ended fashion. Also, the term “or” is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term "or" means one, some, or all of the elements in the list.

[0098] Overall, the language of the claims is to be interpreted broadly based on the language employed in the claims. The language of the claims is not to be limited to the non-exclusive embodiments and examples that are illustrated and described in this disclosure, or that are discussed during the prosecution of the application.

[0099] Although systems, devices, and methods for endovascular implants and accurate placement thereof have been disclosed in the context of certain embodiments and examples, this disclosure extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses of the embodiments and certain modifications and equivalents thereof. Various features and aspects of the disclosed embodiments can be combined with or substituted for one another in order to form varying modes of systems, devices and methods for endovascular implants and accurate placement thereof. The scope of this disclosure should not be limited by the particular disclosed embodiments described herein.

[0100] Certain features that are described in this disclosure in the context of separate implementations can be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can be implemented in multiple implementations separately or in any suitable subcombination. Although features may be described herein as acting in certain combinations, one or more features from a claimed combination can. in some cases, be excised from the combination, and the combination may be claimed as any subcombination or variation of any subcombination.

[0101] While the methods and devices described herein may be susceptible to various modifications and alternative forms, specific examples thereof have been shown in the drawings and are herein described in detail. It should be understood, however, that the invention is not to be limited to the particular forms or methods disclosed, but, to the contrary, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the various embodiments described and the appended claims. Further, the disclosure herein of any particular feature, aspect, method, property, characteristic, quality, attribute, element, or the like in connection with an embodiment can be used in all other embodiments set forth herein. Any methods disclosed herein need not be performed in the order recited. Depending on the embodiment, one or more acts, events, or functions of any of the algorithms, methods, or processes described herein can be performed in a different sequence, can be added, merged, or left out altogether (e.g., not all described acts or events are necessary for the practice of the algorithm). In some embodiments, acts or events can be performed concurrently, e.g., through multi -threaded processing, interrupt processing, or multiple processors or processor cores or on other parallel architectures, rather than sequentially. Further, no element, feature, block, or step, or group of elements, features, blocks, or steps, are necessary or indispensable to each embodiment. Additionally, all possible combinations, subcombinations, and rearrangements of systems, methods, features, elements, modules, blocks, and so forth are within the scope of this disclosure. The use of sequential, or time-ordered language, such as ‘‘then,'’ "next.'’ “after,"’ “subsequently,” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to facilitate the flow of the text and is not intended to limit the sequence of operations performed. Thus, some embodiments may be performed using the sequence of operations described herein, while other embodiments may be performed following a different sequence of operations.

[0102] Moreover, while operations may be depicted in the drawings or described in the specification in a particular order, such operations need not be performed in the particular order shown or in sequential order, and all operations need not be performed, to achieve the desirable results. Other operations that are not depicted or described can be incorporated in the example methods and processes. For example, one or more additional operations can be performed before, after, simultaneously, or between any of the described operations. Further, the operations may be rearranged or reordered in other implementations. Also, the separation of various system components in the implementations described herein should not be understood as requiring such separation in all implementations, and it should be understood that the described components and systems can generally be integrated together in a single product or packaged into multiple products. Additionally, other implementations are within the scope of this disclosure.

[0103] Some embodiments have been described in connection with the accompanying figures. Certain figures are drawn and/or shown to scale, but such scale should not be limiting, since dimensions and proportions other than what are shown are contemplated and are within the scope of the embodiments disclosed herein. Distances, angles, etc. are merely illustrative and do not necessarily bear an exact relationship to actual dimensions and layout of the devices illustrated. Components can be added, removed, and/or rearranged. Further, the disclosure herein of any particular feature, aspect, method, property, characteristic, quality, attribute, element, or the like in connection with various embodiments can be used in all other embodiments set forth herein. Additionally, any methods described herein may be practiced using any device suitable for performing the recited steps.

[0104] The methods disclosed herein may include certain actions taken by a practitioner; however, the methods can also include any third-party instruction of those actions, either expressly or by implication. For example, actions such as “positioning an electrode” include “instructing positioning of an electrode.”

[0105] In summary⁷, various embodiments and examples of endovascular implants and devices and methods for accurate placement have been disclosed. Although the systems, devices and methods for endovascular implants and accurate placement thereof have been disclosed in the context of those embodiments and examples, this disclosure extends beyond the specifically disclosed embodiments to other alternative embodiments and/or other uses of the embodiments, as well as to certain modifications and equivalents thereof. This disclosure expressly contemplates that various features and aspects of the disclosed embodiments can be combined with, or substituted for, one another. Thus, the scope of this disclosure should not be limited by the particular disclosed embodiments described herein, but should be determined only by a fair reading of the claims that follow or that are presented in the future.

[0106] The ranges disclosed herein also encompass any and all overlap, subranges, and combinations thereof. Language such as “up to,” “at least,” “greater than,” “less than,” “between,” and the like includes the number recited. Numbers preceded by a term such as “about” or “approximately” include the recited numbers and should be interpreted based on the circumstances (e.g., as accurate as reasonably possible under the circumstances, for example ±5%, ±10%, ±15%, etc.). For example, “about 1 V” includes “1 V.” Phrases preceded by a term such as “substantially” include the recited phrase and should be interpreted based on the circumstances (e g., as much as reasonably possible under the circumstances). For example, “substantially perpendicular” includes “perpendicular.” Unless stated otherwise, all measurements are at standard conditions including temperature and pressure. NUMBERED EMBODIMENTS OF THE INVENTION

[0107] 1. A tissue ablation system configured to reduce a risk of bums on a patient during an ablation procedure, the tissue ablation system comprising: a radio frequency (RF) generator configured to generate ablation energy; an ablation device configured to be electrically coupled with the RF generator and configured to receive the ablation energy from the RF generator, the ablation device comprising an active electrode configured to deliver the ablation energy' originating from the RF generator to a target tissue of the patient to ablate the target tissue; and a plurality of dispersive electrode portions configured to be coupled to the skin of the patient, wherein each dispersive electrode portion is configured to be coupled to the skin of the patient at a location not overlapping with any other dispersive electrode portion, and wherein each dispersive electrode portion is configured to conduct an electrical current between the skin of the patient where the dispersive electrode portion is coupled and the RF generator; wherein the RF generator comprises one or more hardware processors configured to: monitor an initial resistance between each of the dispersive electrode portions at a beginning of an ablation; monitor a real-time resistance between each of the dispersive electrode portions during the ablation; monitor a total ablation energy provided from the RF generator to the ablation device; and terminate the ablation in response to determining that: the real-time resistance satisfies a condition relative to the initial resistance; and the total ablation energy’ provided from the RF generator to the ablation device exceeds an energy threshold.

[0108] 2. The tissue ablation system of embodiment 1, yvherein the plurality of dispersive electrode portions comprises a plurality of dispersive electrodes.

[0109] 3. The tissue ablation system of embodiment 1, wherein the plurality’ of dispersive electrode portions comprises one split dispersive electrode. [0110] 4. The tissue ablation system of any of embodiments 1-3, wherein the one or more hardware processors are further configured to monitor a real-time temperature of at least one dispersive electrode portion.

[0111] 5. The tissue ablation system of embodiment 2, wherein the plurality of dispersive electrode portions comprises: a first dispersive electrode configured to be coupled to the skin of the patient at a first location and configured to conduct a first electrical current between the skin of the patient at the first location and the RF generator; and a second dispersive electrode configured to be coupled to the skin of the patient at a second location and configured to conduct a second electrical current between the skin of the patient at the second location and the RF generator.

[0112] 6. The tissue ablation system of any of embodiment 1-5, wherein the one or more hardware processors are configured to determine that the real-time resistance satisfies the condition if a difference between the real-time resistance and initial resistance exceeds a resistance threshold.

[0113] 7. The tissue ablation system of embodiment 6, wherein the resistance threshold is about 4.5 Ohms.

[0114] 8. The tissue ablation system of any of embodiments 1-5, wherein the one or more hardware processors are configured to determine that the real-time resistance satisfies the condition if a ratio of the real-time resistance to the initial resistance exceeds a resistance threshold.

[0115] 9. The tissue ablation system of embodiment 8, wherein the one or more hardware processors are configured to determine that the real-time resistance satisfies the condition if the following ratio exceeds a resistance threshold: wherein R(t) is the real-time resistance, and wherein bi is the initial resistance between each of the dispersive electrode portions at a beginning of an ablation.

[0116] 10. The tissue ablation system of embodiment 9, wherein the resistance threshold is about 3%.

[0117] 11. The tissue ablation system of any of embodiments 1-10, wherein the energy threshold is between 30kJ and 50kJ. [0118] 12. The tissue ablation system of any of embodiment 1-11, wherein the total ablation energy’ comprises a total amount of ablation energy provided since the beginning of the ablation.

[0119] 13. The tissue ablation system of any of embodiments 1-12, wherein the one or more hardware processors are configured to terminate the ablation in response to determining that an expected ablation energy exceeds an expected energy' threshold.

[0120] 14. The tissue ablation sy stem of embodiment 13, wherein the one or more hardware processors are configured to allow the ablation to continue in response to determining that an expected ablation energy is within an expected energy threshold.

[0121] 15. The tissue ablation system of embodiment 1, wherein the target tissue is a uterine fibroid, and wherein the active electrode is configured to deliver the ablation energy to the uterine fibroid.

[0122] 16. The tissue ablation system of embodiment 15. wherein the active electrode is configured to deliver the ablation energy to the uterine fibroid trans cervically.

[0123] 17. A computer-implemented method performed under control of one or more hardware processors executing program instructions, the computer-implemented method comprising: monitoring an initial resistance at a beginning of an ablation between a first dispersive electrode portion coupled to the skin of the patient at a first location and a second dispersive electrode portion coupled to the skin of the patient at a second location; monitoring a real-time resistance between the first dispersive electrode portion and the second dispersive electrode portion during the ablation; monitoring a total ablation energy provided from the RF generator to the ablation device; and terminating the ablation in response to determining that: the real-time resistance satisfies a condition relative to the initial resistance; and the total ablation energy' provided from the RF generator to the ablation device exceeds an energy threshold.

[0124] 18. A tissue ablation system configured to reduce a risk of bums on a patient during an ablation procedure, the tissue ablation system comprising: a radio frequency (RF) generator configured to generate ablation energy'; an ablation device configured to be electrically coupled with the RF generator and configured to receive the ablation energy from the RF generator, the ablation device comprising an active electrode configured to deliver the ablation energy originating from the RF generator to a target tissue of the patient to ablate the target tissue; a plurality of dispersive electrode portions configured to be coupled to the skin of the patient, wherein each dispersive electrode portion is configured to be coupled to the skin of the patient at a location not overlapping with any other dispersive electrode portion, and wherein each dispersive electrode portion is configured to conduct an electrical current between the skin of the patient where the dispersive electrode portion is coupled and the RF generator; wherein the RF generator comprises one or more hardware processors configured to: monitor the electrical cunent conducted from each dispersive electrode portion during an ablation; monitor a total ablation energy provided from the RF generator to the ablation device; and terminate the ablation in response to determining that: the electrical current conducted from any dispersive electrode portion exceeds the electrical current conducted by any other dispersive electrode portion by more than a current threshold; and the total ablation energy provided from the RF generator to the ablation device exceeds an energy threshold.

[0125] 19. The tissue ablation system of embodiment 18, wherein the plurality of dispersive electrode portions comprises a plurality⁷ of dispersive electrodes.

[0126] 20. The tissue ablation system of embodiment 18, wherein the plurality of dispersive electrode portions comprises one split dispersive electrode.

[0127] 21. The tissue ablation system of embodiment 18, wherein the one or more hardware processors are further configured to monitor a temperature of at least one dispersive electrode portion.

[0128] 22. The tissue ablation system of embodiment 18. wherein the plurality of dispersive electrode portions comprises: a first dispersive electrode configured to be coupled to the skin of the patient at a first location and configured to conduct a first electrical current between the skin of the patient at the first location and the RF generator; and a second dispersive electrode configured to be coupled to the skin of the patient at a second location and configured to conduct a second electrical current between the skin of the patient at the second location and the RF generator.

[0129] 23. The tissue ablation system of embodiment Error! Reference source not found., wherein the one or more hardware processors are configured to determine that first electrical current exceeds the second electrical current by more than the cunent threshold if a ratio of the first electrical current to the second electrical current exceeds the current threshold.

[0130] 24. The tissue ablation system of embodiment Error! Reference source not found., wherein the one or more hardware processors are configured to determine that first electrical current exceeds the second electrical current by more than the cunent threshold if a ratio of a square of the first electrical current to a square of the second electrical current exceeds the cunent threshold.

[0131] 25. The tissue ablation system of embodiment Error! Reference source not found., wherein the cunent threshold is 1.35.

[0132] 26. The tissue ablation system of embodiment Error! Reference source not found., wherein the energy' threshold is between 40kJ and 60kJ.

[0133] 27. The tissue ablation system of embodiment Error! Reference source not found., wherein the total ablation energy comprises a total amount of ablation energy provided since the beginning of the ablation.

[0134] 28. The tissue ablation system of embodiment Error! Reference source not found., wherein the one or more hardware processors are configured to terminate the ablation in response to determining that an expected ablation energy exceeds an expected energy threshold.

[0135] 29. The tissue ablation system of embodiment Error! Reference source not found., wherein the one or more hardware processors are configured to allow the ablation to continue in response to determining that an expected ablation energy is within an expected energy threshold. [0136] 30. The tissue ablation system of embodiment Error! Reference source not found., wherein the target tissue is a uterine fibroid, and wherein the active electrode is configured to deliver the ablation energy' to the uterine fibroid.

[0137] 31. The tissue ablation system of embodiment Error! Reference source not found., wherein the active electrode is configured to deliver the ablation energy' to the uterine fibroid transcervically.

[0138] 32. A computer-implemented method performed under control of one or more hardware processors executing program instructions, the computer-implemented method comprising: monitoring a first electrical current conducted from a first dispersive electrode portion coupled to a patient at a first location during an ablation; monitoring a second electrical current conducted from a second dispersive electrode portion coupled to the patient at a second location during the ablation; monitoring a total ablation energy provided from the RE generator to the ablation device; and terminating the ablation in response to determining that: the first electrical cunent exceeds the second electrical current by more than a current threshold; and the total ablation energy^ provided from the RF generator to the ablation device exceeds an energy' threshold.

Claims

WHAT IS CLAIMED IS:

1. A tissue ablation system configured to reduce a risk of bums on a patient during an ablation procedure, the tissue ablation system comprising: a radio frequency (RF) generator configured to generate ablation energy; an ablation device configured to be electrically coupled with the RF generator and configured to receive the ablation energy from the RF generator, the ablation device comprising an active electrode configured to deliver the ablation energy originating from the RF generator to a target tissue of the patient to ablate the target tissue; and a plurality of dispersive electrode portions configured to be coupled to the skin of the patient, wherein each dispersive electrode portion is configured to be coupled to the skin of the patient at a location not overlapping with any other dispersive electrode portion, and wherein each dispersive electrode portion is configured to conduct an electrical current between the skin of the patient where the dispersive electrode portion is coupled and the RF generator; wherein the RF generator comprises one or more hardware processors configured to: monitor at least one of a real-time resistance between the dispersive electrode portions during the ablation and real-time currents conducted by the dispersive electrode portions during the ablation; monitor a total ablation energy' provided from the RF generator to the ablation device; and terminate the ablation in response to determining that: one of the at least one of the real-time resistance and the real-time currents satisfies a condition; and the total ablation energy provided from the RF generator to the ablation device exceeds an energy threshold.

2. The tissue ablation system of claim 1, wherein the plurality of dispersive electrode portions comprises a plurality of dispersive electrodes.

3. The tissue ablation system of claim 1, wherein the plurality of dispersive electrode portions comprises one split dispersive electrode.

4. The tissue ablation system of claim 1. wherein the one or more hardware processors are further configured to monitor a real-time temperature of the dispersive electrode portions.

5. The tissue ablation system of claim 1, wherein the at least one of the real-time resistance and the real-time currents comprises the real-time resistance; wherein the one or more hardware processors are configured to monitor an initial resistance between the dispersive electrode portions at a beginning of an ablation; and wherein the one or more hardware processors are configured to determine that the real-time resistance satisfies the condition if a difference between the real-time resistance and the initial resistance exceeds a resistance threshold.

6. The tissue ablation system of claim 5. wherein the one or more hardware processors are configured to determine that the real-time resistance satisfies the condition if a difference between the real-time resistance and the initial resistance exceeds a resistance threshold.

7. The tissue ablation system of claim 5. wherein the one or more hardware processors are configured to determine that the real-time resistance satisfies the condition if a ratio of the real-time resistance to the initial resistance exceeds a resistance threshold.

8. The tissue ablation system of claim 7, wherein the one or more hardware processors are configured to determine that the real-time resistance satisfies the condition if the following ratio exceeds a resistance threshold: wherein R(t) is the real-time resistance, and wherein bi is the initial resistance between the dispersive electrode portions at a beginning of an ablation.

9. The tissue ablation system of claim 1, wherein the total ablation energy comprises a total amount of ablation energy provided since the beginning of the ablation.

10. The tissue ablation system of claim 1, wherein the one or more hardware processors are configured to terminate the ablation in response to determining that an expected ablation energy exceeds an energy threshold.

11. The tissue ablation system of claim 1, wherein the one or more hardware processors are configured to allow the ablation to continue in response to determining that an expected ablation energy is within an energy threshold.

12. The tissue ablation system of claim 1, wherein the at least one of the real-time resistance and the real-time currents comprises the real-time currents: and wherein the one or more hardware processors are configured to determine that the real-time currents satisfy the condition if a function of the electrical current conducted from any dispersive electrode portion exceeds a function of the electrical current conducted by any other dispersive electrode portion by more than a current threshold.

13. The tissue ablation system of claim 12, wherein the current threshold is a current threshold ratio.

14. The tissue ablation system of claim 12, wherein the function of the electrical current conducted from any dispersive electrode portion is square of the electrical current conducted from any dispersive electrode portion, and wherein the function of the electrical current conducted by any other dispersive electrode portion is a square of the electrical current conducted by any other dispersive electrode portion.

15. The tissue ablation system of claim 1, wherein the at least one of the real-time resistance and the real-time currents comprises both the real-time resistance and the realtime currents.