TECHNICAL FIELD

[0001] The disclosure generally relates to systems and methods of delivering energy to electrosurgical devices. More specifically, it relates to delivering energy to a plurality of cooled energy delivery devices.

SUMMARY

[0002] A system effectively delivers electrical energy through multiple cooled probes through the coordination of temperature management (i.e. managing the delivery of cooling fluid to the probes) with multiplexed energy delivery.

[0003] In a first broad aspect, embodiments of the present invention comprise a system for delivering energy to a tissue. The system comprises: at least two electrosurgical devices operable to deliver energy to the tissue; an energy source operable to be connected to the at least two electrosurgical devices and to provide energy to the at least two electrosurgical devices; at least one fluid source operable to be coupled to the at least two electrosurgical devices for providing a fluid to the at least two electrosurgical devices; and a control system. The control system is operable to coordinate delivery of energy from the energy source to the at least two electrosurgical devices with delivery of fluid from the fluid source to the at least two electrosurgical devices.

[0004] In a second broad aspect, embodiments of the present invention comprise a system for use with at least two electrosurgical devices and at least one fluid source, the at least one fluid source providing a fluid to the at least two electrosurgical devices. The system comprises: an energy source operable to be connected to the at least two electrosurgical devices and to provide energy to the at least two electrosurgical devices; and a control system. The control system is operable for coordinating delivery of energy from the energy source to the at least two electrosurgical devices with delivery of fluid from the fluid source to the at least two electrosurgical devices.

[0005] As a feature of the first and second broad aspects, the control system is operable to coordinate the delivery of energy from the energy source to the at least two electrosurgical devices with delivery of fluid from the fluid source to the at least two electrosurgical devices when the delivery of fluid is substantially concurrent with the delivery of energy. In some embodiments, the control system is integral with the energy source. In some embodiments, the control system is operable to multiplex the delivery of energy from the energy source to the at least two electrosurgical devices. [0006] As a feature of the first and second broad aspects, the system further comprises a pumping unit coupled to the at least one fluid source and the at least two electrosurgical devices for delivering the fluid to the at least two electrosurgical devices. In some embodiments, the pumping unit comprises a single pump. In some other embodiments, the pumping unit comprises two pumps, the two pumps both being coupled to the at least one fluid source. In some embodiments, the at least two electrosurgical devices comprise a quantity of electrosurgical devices, and wherein the pumping unit comprises a quantity of pumps equal to the quantity of electrosurgical devices.

[0007] Some embodiments of the first and second broad aspects further comprise tubing for connecting the at least two electrosurgical devices to the pumping unit wherein a first portion of the tubing is operable to connect the pumping unit to a first electrosurgical device of the at least two electrosurgical devices, a second portion of the tubing is operable to connect the first electrosurgical device to a second electrosurgical device of the at least two electrosurgical devices, and a third portion of the tubing is operable to connect the second electrosurgical device to the pumping unit whereby the fluid provided by the at least one fluid source is able to flow into the first electrosurgical device, then subsequently into the second electrosurgical device and then return to the pumping unit. In some such embodiments, the pumping unit comprises at least two pumps and wherein the at least two electrosurgical devices comprise at least two pairs of electrosurgical devices, and wherein each pair of electrosurgical devices are connected to one of the at least two pumps. In some examples, the pumping unit comprises two pumps and wherein the system comprises two pairs of electrosurgical devices.

[0008] In some embodiments of the first and second broad aspects, the at least two electrosurgical devices comprise a third electrosurgical device, the system further comprises tubing for connecting the at least two electrosurgical devices to the pumping unit wherein a first portion of the tubing is operable to connect the pumping unit to a first electrosurgical device of the at least two electrosurgical devices, a second portion of the tubing is operable to connect the first electrosurgical device to a second electrosurgical device of the at least two electrosurgical devices, a third portion of the tubing is operable to connect the second electrosurgical device to the third electrosurgical device, and a fourth portion of the tubing is operable to connect the third electrosurgical device to the pumping unit, whereby the fluid provided by the at least one fluid source is able to flow into the first electrosurgical device, then into the second electrosurgical device, then subsequently into the third electrosurgical device, and then return to the pumping unit.

[0009] As a feature of the first and second broad aspects, the energy is electrical energy. In some such embodiments, the electrical energy is in a radiofrequency range.

[0010] As a feature of the first and second broad aspects, the energy source has at least two channels and the system is operable to simultaneously deliver energy through the at least two channels. In some such embodiments, the at least two channels are accessible through at least two connectors located on the energy source. In some embodiments, the system further comprises a cable hub in electrical communication with the energy source and wherein the at least two channels are accessible through connectors located on the cable hub.

[0011] In some embodiments of the system, at least two electrosurgical devices comprise at least one uncooled electrosurgical device.

[0012] In a third broad aspect, embodiments of the present invention comprise a method for delivering energy to tissue. The method comprises: connecting at least two electrosurgical devices to an energy source; connecting the at least two electrosurgical devices to at least one fluid source; delivering energy from the energy source to tissue via the at least two electrosurgical devices; and delivering fluid to the at least two electrosurgical devices. In some embodiments, the at least two electrosurgical devices comprise four electrosurgical devices.

[0013] In some embodiments of the method, energy is delivered to the tissue through the at least two electrosurgical devices to form a single lesion. Some such embodiments further comprise monitoring a temperature of the single lesion at more than one location and controlling delivering energy and delivering fluid to the at least two electrosurgical devices based on the temperature of the single lesion. Some such embodiments include monitoring a temperature of the single lesion comprises monitoring the temperature at four different locations.

[0014] In some embodiments of the third aspect, the energy is delivered through the at least two electrosurgical devices to form at least two lesions substantially concurrently. In some such embodiments, the at least two lesions comprise four lesions.

[0015] Some embodiments of the method further comprise controlling a temperature of the tissue by delivering the fluid to the at least two electrosurgical devices. In some such embodiments, the at least two electrosurgical devices comprise a cooled electrosurgical device and an uncooled electrosurgical device, and the method comprises substantially concurrently delivering energy through the cooled electrosurgical device and the uncooled electrosurgical device. In some embodiments, the step of delivering fluid to at least one electrosurgical device of the at least two electrosurgical devices is substantially concurrent with the step of delivering energy to the at least one electrosurgical device, wherein the step of delivering fluid to the at least one electrosurgical device ceases substantially upon termination of delivering energy to the at least one electrosurgical device. In some embodiments, the step of delivering fluid to at least one electrosurgical device of the at least two electrosurgical devices is substantially concurrent with at least a portion of the step of delivering energy to the at least one electrosurgical device. [0016] Some embodiments further comprise a step of priming the at least two electrosurgical devices with the fluid prior to delivering energy in order to verify that the at least two electrosurgical devices are properly connected to the fluid source.

[0017] In some embodiments of the method, the step of connecting the at least two electrosurgical devices to at least one fluid source comprises connecting a pair of electrosurgical devices from the at least two electrosurgical devices to the fluid source in a daisy-chained manner to enable fluid flow from a first electrosurgical device of the pair of electrosurgical devices to a second electrosurgical device of the pair of electrosurgical devices, and then from the second electrosurgical device to the fluid source. In some such embodiments, a first pair of electrosurgical devices are daisy chained together and a second pair of electrosurgical devices are daisy chained together for concurrent cooling of the first pair of electrosurgical devices and the second pair of electrosurgical devices while delivering energy.

[0018] Some embodiments of the method further comprise a step of terminating delivering energy when a measured channel impedance is outside of a predetermined range. Some embodiments further comprise the step of terminating delivery of energy and fluid when a measured tissue temperature is outside of a predetermined range.

[0019] In some embodiments of the method, the energy is delivered to at least one electrosurgical device of the at least two electrosurgical devices in a bipolar manner. In some such embodiments, the energy is delivered to the tissue in a bipolar manner using a bipolar electrosurgical device having two or more electrodes wherein at least one electrode is an active electrode and at least one electrode is a return electrode. In some embodiments, the energy is delivered to the tissue in a bipolar manner using a pair of electrosurgical devices wherein the energy flows between the pair of electrosurgical devices.

[0020] In some embodiments of the third aspect, wherein the energy source comprises a control system, the method further comprises using the control system to coordinate multiplexing of the energy being delivered to the at least two electrosurgical devices with management of the fluid being delivered to the at least two electrosurgical devices. In some such embodiments, the control system is operable to substantially concurrently coordinate multiplexing of the energy and management of the fluid.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order that the invention may be readily understood, embodiments of the invention are illustrated by way of examples in the accompanying drawings, in which:

[0022] Fig. 1 is an illustration of an embodiment of a system of the present invention;

[0023] Fig. 2 is an illustration of an embodiment of a GU I during a pump priming generator mode;

[0024] Fig. 3 is an illustration of an embodiment of a GU I during delivery of energy to tissue; and [0025] Fig. 4 is a schematic diagram of an embodiment of a system of the present invention.

DETAILED DESCRIPTION

[0026] Currently, in the pain management field, it is generally not possible to deliver coaxial bipolar or monopolar cooled radiofrequency (RF) electrical energy through multiple channels (e.g. four channels) of an RF generator (i.e. an energy source) simultaneously.

[0027] Using cooled RF technology allows for more power to be safely delivered than with uncooled technology, thereby increasing the ablation size when compared to conventional (uncooled) radiofrequency ablation. The ability to deliver cooled RF electrical energy through multiple channels (e.g. four channels) simultaneously allows for multiple procedures to be performed happen in parallel, thereby saving a physician's time as well as reducing treatment time. Further, the ability to deliver cooled RF through multiple channels simultaneously allows for an increased total lesion size along with the ability to monitor lesion temperature at multiple (e.g. four) different points.

[0028] The present inventors have conceived and reduced to practice a system and method that effectively delivers electrical energy through multiple cooled probes by the coordination of temperature management (i.e. managing the delivery of cooling fluid to the probes) with multiplexed energy delivery. The system for delivering energy to a tissue comprises at least two electrosurgical devices operable to deliver energy to the tissue; an energy source operable to be connected to the at least two electrosurgical devices and to provide energy to the at least two electrosurgical devices; at least one fluid source operable to be coupled to the at least two electrosurgical devices for providing a fluid to the at least two electrosurgical devices; and a control system. The control system is operable to coordinate delivery from the energy source to the at least two electrosurgical devices with delivery of fluid from the fluid source to the at least two electrosurgical devices.

[0029] The electrosurgical system includes a control system which is able to actively manage fluid delivery to all multiple electrosurgical devices (e.g. four probes) while multiplexing between the four channels such that Cooled RF delivery to all four probes can be maintained. In some embodiments both fluid management and channel multiplexing happen simultaneously along with an underlying power distribution algorithm that will allocate power intelligently to ensure that the channels that require more power receive it, without the other channels being significantly affected.

[0030] Furthermore, the control system also maintains USB serial communication with a pumping unit and actively analyzes the state of all active probes in order to verify that proper cooling is being delivered. In addition to the check of whether proper cooling is being applied, the system has built in error logic to prevent and terminate procedures that are outside of a selected impedance or temperature range as a safety precaution. In some embodiments, the system software checks the impedance of a channel, and will give an error if the impedance is above 3000 or under 25 ohms. In some such embodiments, the measurement process comprises an RF pulse being sent approximately every 100 ms at a certain voltage and based on the current output, the impedance is calculated.

[0031] Additionally, before using a pumping unit, a generator priming mode primes fluid through the probes in order to verify that the pump and tubing are functioning properly. The system also includes a user interface such as a graphical user interface (GU I) to provide for output to the user and user input.

[0032] In typical embodiments of the system, the user chooses whether or not to use cooling through the selection of the type of cable hub. If a cooled hub is selected and connected to the electrosurgical devices (e.g. probes), cooled lesion procedures can be performed. If a standard (uncooled) hub is connected, standard lesion procedures can be performed. The control system can modulate various cooling parameters such as flow rate, and switching between pumps, switching cooling between probes that are getting cooled, and termination and initiation of the pumping unit. Inputs to the control system includes the number of probes connected, the power requirements of each probe, the tissue temperature of each probe, the impedance of each channel, the procedure time of each channel and the generator's overall state. Certain embodiments include active control of fluid delivery such that the flow rate is controlled in order to optimize lesion size and/or procedure time. This active control is applied based on various factors such as tissue temperature, power output and impedance.

[0033] The disclosed surgical systems are operable for simultaneous cooled RF energy delivery through multiple channels (e.g. four channels) and typically include a pumping unit, a generator, a tube kit, cooled RF probes (e.g. four probes), and a cooled RF cable hub. When preparing a typical system, the user first connects a cooled RF hub to the generator, and then the cooled RF probes to the cable hub. The tube kit along with the necessary tubing is then connected and the pump is then connected to the generator. Once the generator is turned on, it enters the sensory stimulation mode by default whereby the user can confirm the location of probes relative to sensory nerves. In typical embodiments of the system, the user has the option of simultaneously starting all four probes in cooled lesion mode by pressing a cooled lesion RF button, assuming no errors are present and that pump priming completes successfully. Alternatively, the GU I provides input options which allow a user to select individual probes.

[0034] In typical embodiments, four channels are available through individual ports (i.e. connectors) located on a cooled RF hub, while in alternative embodiments the ports are located directly on the generator. These ports serve as the electrical connectors to the generator. Software logic in the control system of the generator allows four separate channels to deliver Cooled RF simultaneously. Alternative embodiments have fewer or more than four channels. In some embodiments, the apparatus used for4- channel simultaneous cooled RF energy delivery includes two pumps for four probes wherein each pump has two probes daisy chained to it. Alternatively, another method of cooling the four probes is through the use of individual pumps for each of the active channels such that there are four separate pumps for four probes. In alternative embodiments, the number of pumps used is 1, 3, or more than 4.

[0035] Daisy chaining is the connection of several devices together in a linear fashion (in series). In the context of this application, it refers to stringing one end of a pump through two probes and back into the other end of the pump through the use of tubing. In some embodiments, the apparatus for daisy chaining two probes to one pump includes tubing for providing fluid running from the pumping unit to a first probe, and further tubing connecting the first probe to a second probe whereby fluid exiting the first probes enters the second probe, and yet further tubing connecting the second probe to the pumping unit whereby fluid exits the second probe and returns to the pumping unit. In alternative embodiments, a third probe is daisy chained to the second probe by using an additional portion of tubing which connects the second and third probes, and tubing connecting the third probe to the pumping unit whereby fluid can exit the third probe and return to the pumping unit.

[0036] In some other alternative embodiments, more than one probe is attached to a pump and the pump is used to cool the multiple probes by switching the application of cooling between the probes.

[0037] Embodiments of the present invention allow for a single large lesion to be created. For example, a single lesion can be created more rapidly using four channels (and the connected probes) simultaneously than using a single channel. The lesion size is typically larger if the probes are cooled than if a similar 4-channel procedure was performed using conventional (uncooled) RF ablation.

[0038] Furthermore, embodiments of the present invention allow for the creation of four lesions in parallel (simultaneously). Typically each of the lesion sizes is relatively larger if the probes are cooled than if a similar 4-channel procedure is performed using conventional (uncooled) RF ablation.

[0039] In addition, embodiments of the present invention allow for temperature monitoring of a single lesion at up to four different points to provide more information for controlling the procedure.

[0040] By extension, embodiments of the present invention may be used with even more (or less) probes or temperature sensors than the four described herein.

[0041] With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of certain embodiments of the present invention only. Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting. [0042] Figure 1 illustrates an exemplary embodiment of a system 100 of the present invention. System 100 includes

hub 101 which is a cooled RF hub and allows for the connection of up to four cooled RF probes 106. Alternative embodiments of system 100 do not include hub 101 and the probes are electrically connected to the generator at the RF board.

[0043] Generator 102 electrically connects with hub 101 via a cable not shown in the figure. GU I 103 (a graphical user interface) is on the generator 102 and allows for user interaction. Some embodiments of the GU I include a user interface specifically configured for cooled RF energy delivery. In some such embodiments, the GU I 103 is capable of displaying status (temperature, power, impedance, and remaining procedure time) of four different channels when delivering RF energy on each of the channels (see Fig. 3), and each of the channels have corresponding graphs on the screen that show the change in power and temperature over time. Fig. 3 illustrates examples of temperature plot 112 temperature and power plot 110 for a four channel system. A cooled RF probe 106 (Fig. 1) is used to deliver radiofrequency electrical energy for cooled RF ablation. Fig. 1 illustrates each probe 106 having tubing 105 running to it from the pumping unit 104 which allows for cooling when water is passed through.

[0044] The control system software algorithm, is typically included in the generator 102, and is operable for cooled RF energy delivery. It includes a pump priming mode for preparing the pumps, tubing and probes. Pump priming mode checks to verify that the temperature read by the Cooled RF probe is below a threshold (which in some embodiments is below 34 degrees Celsius) to indicate effective cooling i.e. the cooling should drop the temperature below body temperature while not cooling the tissue too much. In some embodiments, the threshold ranges from about 30 degrees Celsius to about 36 degrees Celsius. Fig. 2 illustrates the GUI 103 of a system during pump priming mode.

[0045] Fig. 4 is a schematic diagram which shows a control system (or a controller) of the electrosurgical system. The controller actively manages fluid delivery to all electrosurgical devices (e.g. four probes) while multiplexing between the channels such that cooled RF delivery to all the devices can be maintained. In some embodiments, both fluid management and channel multiplexing happen simultaneously. Some embodiments include only delivering cooling fluid to a probe while it is actually delivering energy to tissue to thereby increase efficiency and minimize fluctuations in power delivery. Some embodiments include only delivering cooling fluid to a probe for a portion of the time it is delivering energy. Fig. 4, also illustrates the connection between the controller and GU I 103 which allows a user to monitor the electrosurgical system and to input into the system. [0046] Typical embodiments of the control algorithm include temperature checks during active ablation to confirm the temperature readings from the cooled RF probes are within an acceptable range for the procedure being performed. The algorithm also verifies that the cooling is applied to all probes.

[0047] The system provides that default settings are available for cooled RF energy delivery so that the user is provided with suggested settings which they can then adjust, if necessary, for the procedure they are performing.

[0048] Pumping unit 104 is connected to the generator, for example via a universal serial bus (USB). In some embodiments, pumping unit 104 comprises two pumps and two probes daisy chained to each pump; allowing for a total of four cooled RF probes to be active at any given time. In other embodiments, more probes may be utilized.

[0049] Tubing 105 allows cooling fluid (e.g. water) to flow from the pumping unit 104 through the probes 106. In some embodiments, to facilitate daisy chaining probes for cooling, tubing 105 and the tubing connectors are designed to withstand the added pressure of having two probes connected to each pump rather than just one probe.

[0050] In alternative embodiments of system 100, the number of probes that can be used simultaneously differs (i.e. it is greater or less than four). In some alternative embodiments, the combination of probes that are used simultaneously varies i.e. instead of all cooled RF probes, a combination of cooled RF and conventional (uncooled) RF probes are used. In some embodiments, each pump cools just one probe, rather than daisy chaining two probes to one pump. Some alternatives comprise energy being delivered in a bipolar manner. For example, using a single probe with two or more electrodes wherein one of the electrodes is active and another is a return electrode. Other bipolar embodiments include using a pair of probes wherein energy flows between the probes to thereby heat tissue.

[0051] The embodiments of the invention described above are intended to be exemplary only. The scope of the invention is therefore intended to be limited solely by the scope of the appended claims.

[0052] It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination.

[0053] Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the broad scope of the appended claims. All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention.