Power allocation method

Abstract

Disclosed herein is a method and apparatus for using a generator that is insufficiently powerful to power multiple electrosurgical probes during ramping of the probes to a set point temperature. The method includes reducing energy delivery to the probes by temporarily disabling energy delivery to at least one probe. Some embodiments include a method of delivering energy to at least two electrosurgical probes connected to at least two channels of a generator, wherein the generator has a maximum output, the method comprising: (a) activating a channel to be activated; (b) checking for a disable condition; and (c) if the disable condition exists, disabling the channel that consumes the least power among all active channels.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Application Serial No. 62 / 782,663, filed December 20, 2018, the disclosure of which is incorporated herein by reference. Technical Field

[0003] The present disclosure relates to electrosurgical methods. In particular, the present disclosure relates to power distribution to multiple electrosurgical probes. Summary of the invention

[0004] Reducing energy delivery to at least one probe by temporarily halting (or disabling) energy delivery to the probe solves the problem of insufficient generator power to power multiple electrosurgical probes (e.g., 2, 3, or 4) during the ramp-up period to a set-point temperature.

[0005] In a first broad aspect, embodiments of the invention include a method of delivering energy to at least two electrosurgical probes connected to at least two channels of a generator, wherein the generator has a maximum output, the method comprising:

[0006] (a) Activation channel;

[0007] (b) checking for disabling conditions; and

[0008] (c) If a disabling condition exists, disabling at least one channel, such as a channel occupying the least power, a channel occupying the most power, or another channel from all active channels.

[0009] Typically, step (a) comprises activating all channels simultaneously. In typical embodiments, step (b) comprises checking whether at least two electrosurgical probes are active and whether at least one channel is in a ramp-up phase. Typical embodiments further comprise step (b) comprising checking whether the total requested power of all channels is greater than the maximum output of the generator, and step (b) comprises checking whether any channel has been disabled, enabled or stopped by a user within a first system reaction time (e.g., within the last X seconds).

[0010] In some embodiments of the first broad aspect, step (b) includes checking: whether the temperature error of all active channels in the ramp-up is greater than the programmed temperature error of Y degrees within Z seconds; if the temperature error in all active channels is greater than the programmed temperature error of Y degrees within Z seconds; or if the total requested power of all channels is greater than the output power limit of the generator within a time period of Z' seconds.

[0011] Typical embodiments of the method of the first broad aspect further comprise the step (d) of checking for an enable condition and the step (e) of re-enabling the most recently disabled channel if the enable condition exists.

[0012] In a typical embodiment, step (d) further comprises checking whether at least one channel has been disabled by the algorithm within a second system reaction time (eg, the last XX seconds) or checking whether any channel has been disabled, enabled, or stopped by the user.

[0013] In a typical embodiment of the first broad aspect, checking the enable condition (step (d)) includes checking whether the total power used by all active channels is less than (Ptotal-safety factor YY×system wait time enabled ZZ seconds Plast), where Ptotal is the total requested power in all channels at time T, and where Plast is the last output power of the channels disabled at time T, and where time T is the time when the most recently disabled and currently non-enabled channels were turned off.

[0014] In some embodiments of the method, step (d) includes checking whether the total power used by all active channels is less than a selected power level threshold with a safety factor (eg, YY' Watts).

[0015] In a second broad aspect, embodiments of the invention include an electrosurgical system for delivering energy to tissue, the electrosurgical system comprising:

[0016] a generator having a maximum output and at least two channels;

[0017] at least two probes operable to connect to the at least two channels such that the two channels are operable to deliver energy; and

[0018] a control system, wherein when the at least two probes are connected to the at least two channels, the control system is operable to

[0019] (a) Activation channel;

[0020] (b) checking for disabling conditions; and

[0021] (c) If a disabling condition exists, disabling at least one channel, for example, the channel using the least power, or the channel using the greatest power, or some other channels among all active channels.

[0022] Typically, step (a) comprises activating the channels simultaneously. In an exemplary embodiment of the second broad aspect, the control system is operable to perform further functions comprising the step (d) of checking for an enable condition, and the step (e) of re-enabling a most recently disabled channel if the enable condition exists. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order that the present invention may be easily understood, embodiments of the present invention are shown by way of example in the accompanying drawings, in which:

[0024] Figure 1 is a diagram of an embodiment of a system;

[0025] Figure 2 is a flow chart of an embodiment of a method; and

[0026] Figure 3 is a schematic diagram of an embodiment of a generator. DETAILED DESCRIPTION

[0027] The problem of the generator not having sufficient power to power multiple probes (e.g., 2, 3, or 4) during the ramp up to the set point temperature can be addressed by temporarily stopping (or disabling) the energy delivery to at least one probe to reduce the energy delivery to the probe. During the ramp up (i.e., ramp up phase), power is supplied to the probes to increase their temperature to the set temperature (predetermined threshold).

[0028] Radiofrequency (RF) ablation is a minimally invasive procedure for treating patients with chronic pain. In this technique, one or more electrodes of one or more electrosurgical probes are placed adjacent to a target nerve. Radiofrequency current is delivered to the target nerve through the electrodes to produce thermal damage, which is neurodestructive and causes interruption of pain signals to the brain, thereby eliminating pain. Anatomical targets require thermal damage of different sizes as the size of the target changes. Existing systems on the market typically support up to four electrodes at the same time. In most cases, a high-power RF generator is required to perform a procedure using four electrodes at the same time. However, due to regulatory constraints, a typical existing generator has a power limit of 50W, which is insufficient to handle situations where several simultaneous large lesions are required to complete the operation. Generators with a power limit higher than 50 watts (e.g., a 100 watt power limit) may also have similar situations where the generator power limit is insufficient. The method disclosed herein may also be used with such a generator.

[0029] This underpowered situation has led to the development of a method in which the system activates the channels in a staggered manner, with one electrode starting RF delivery while the other electrodes are disabled. Once the active channel has completed the ramp-up time that requires the highest power, the second electrode becomes active and starts RF delivery. This process continues step by step until all electrodes have become active. Staggered activation may be able to handle underpowered situations, but it results in significant delays in program duration (e.g., it may double the duration of some programs). Although staggered activation appears to be a practical method for handling underpowered situations, there are some situations in which the system can handle the simultaneous activation of 2 or 3 electrodes, and then enable the other electrodes once the active electrode has passed the ramp-up time. In this case, staggered activation will unnecessarily increase the program time. In addition, the staggered activation method cannot handle underpowered situations in which the total steady-state power (the power after the ramp-up change is completed) is greater than the total output power of the generator.

[0030] The inventors have conceived and simplified a practical embodiment of a system and method for all multiple probes that reach a set temperature (predetermined threshold) when powered by a generator, the system and method including an algorithm for a controller of a generator system. In a typical embodiment, the set temperature of each channel can be different. The disclosed method may include checking a combination of different conditions to determine the state of the system. There are two states in the program where the system may need to be adjusted: 1) when the system power is limited and a channel needs to be disabled (i.e., the algorithm determines that there is a power shortage and disables the condition of the active channel), and 2) when the system has enough available power to enable the disabled channel. In a typical embodiment, the disabled channel does not deliver energy, i.e., zero energy. In some alternative embodiments, the disabled channel delivers energy at a low level. Typically, the channel is disabled by the algorithm and the generator, and the channel is stopped by the user. For a typical embodiment of the algorithm, the channel stopped by the user will not be re-enabled. The algorithm can be used with unipolar energy delivery, bipolar energy delivery, or a combination of unipolar and bipolar.

[0031] Reference will now be made in particular detail to the accompanying drawings, emphasizing that the details are shown by way of example and for the purpose of illustrative discussion of certain embodiments of the invention. Before explaining at least one embodiment of the invention in detail, it should be understood that the invention is not limited in its application to the details of the construction and arrangement of the components set forth in the following description or shown in the accompanying drawings. The invention can have other embodiments or be practiced or carried out in various ways. Moreover, it should be understood that the words and terms used herein are for descriptive purposes and should not be considered restrictive.

[0032] Figure 1An exemplary embodiment of an electrosurgical system 100 implementing the disclosed method is shown. The electrosurgical system 100 includes a hub 101 that is a cooled RF hub and allows connection of up to four cooled RF probes 106. Alternative embodiments of the system 100 do not include the hub 101, and the probes are electrically connected to the generator at the RF board. Some alternative embodiments of the system include standard (uncooled) probes and appropriate corresponding equipment.

[0033] The generator 102 is electrically connected to the hub 101 via a cable (or other device) not shown in the figure. A GUI 103 (graphical user interface) is on the generator 102 and allows user interaction. Some embodiments of the GUI include a user interface specifically configured for cooling RF energy delivery. In some embodiments, when RF energy is delivered on each of the channels, the GUI 103 can display the status of four different channels (temperature, power, impedance and remaining program time), and each of the channels has a corresponding graph on the screen showing the power and temperature changes over time. The cooled RF probe 106 is used to deliver radio frequency electrical energy for cooled RF ablation. Figure 1 Each probe 106 is shown having a conduit 105 extending thereto from a pumping unit 104, which allows cooling as water passes through the probe.

[0034] Figure 3 is a schematic diagram of an embodiment of a generator 102 . Figure 3 The example of generator 102 includes 4 channels 120, each channel 120 has a single probe line 122 connected thereto. Alternative embodiments of the generator may, for example, include two, three or more than four channels. Typically, each channel 120 has only one probe 106 connected thereto. Each probe line 122 is contained in a cable connected to the channel 120. Typical embodiments of the generator 102 are operable for monopolar and bipolar energy delivery. For monopolar energy delivery, a single line 122 is connected to the probe 106, and a ground pad is attached to the outside of the patient. Bipolar energy delivery can be achieved using two probes (double probe bipolar), wherein each probe 106 is connected to a unique channel 120 (i.e., two probes are connected to two channels), whereby one probe 106 is an active probe, and the second probe is a return probe. Alternatively, a single probe 106 (single probe bipolar) with an active electrode and a return electrode can be used to achieve bipolar energy. A probe 106 configured for single probe bipolar can be connected to two channels, with one channel active and the other channel used for return, or alternatively, the probe 106 can be connected to a single channel for single probe bipolar energy delivery using an adapter (also called a dongle). In the case of dual probe bipolar energy delivery (each probe 106 is connected to a unique channel 120), the algorithm only accepts the temperature reading of one of the two probes as input. The control system software algorithm is typically included in the generator 102.

[0035] The algorithm is operable for cooled RF energy delivery. In alternative embodiments, the algorithm is operable for standard (uncooled) energy delivery. Some alternative embodiments of the generator 101 provide power outside the radio frequency range. The disclosed method can be used in systems that require energy sources to be distributed over multiple channels but the total available power is insufficient to satisfy all channels. The disclosed method can include an algorithm that can be implemented in software of the generator. The algorithm is operable to determine when the system is underpowered and when the system has sufficient power available to activate disabled channels.

[0036] An embodiment of an electrosurgical system 100 includes: a generator 102 having a maximum output and at least two channels; at least two probes 106, the at least two probes being operable to connect to the at least two channels 120 so that the two channels are operable to deliver energy; and a control system. When the at least two probes are connected to the at least two channels, the control system is operable to (a) activate the channel to be activated; (b) check for a disable condition; and (c) if the disable condition exists, disable the channel using the least power among all active channels. Typically, step (a) includes activating the channels simultaneously. In an alternative embodiment of the system, step (c) includes disabling the channel using the most power among all active channels or disabling another channel.

[0037] In one embodiment, the disclosed method may employ a combination of checking different conditions to determine the state of the system. Two possible important states that may occur during a procedure that typically results in a system change are: 1) the system is power limited (i.e., insufficient power), which results in a channel being disabled, and 2) the system has sufficient power available to enable a previously disabled channel. Figure 2 is a flow chart of an embodiment of an algorithm for a method of controlling power distribution. Figure 2 , details are provided below regarding exemplary conditions that may cause the system to disable or re-enable a channel.

[0038] The procedure begins at step 200, which comprises the generator activating at least two of the channels of the generator. Typically, step (a) comprises activating the channels (which are to be activated) simultaneously.

[0039] Disable Channel

[0040] The conditions for disabling a channel are described with respect to steps 210 to 240. If the conditions of steps 210 to 240 are met, the channel in the ramp-up phase is disabled and the minimum power is used among all active channels in the ramp-up (step 250). In an alternative embodiment of the method, step 250 includes disabling the channel using the maximum power among all active channels or disabling another channel.

[0041] Step 210 of the algorithm includes checking whether at least one channel is in the ramp-up phase (i.e., powered to reach the set point temperature). The reason for this is that typical embodiments of the algorithm are intended to address the situation of insufficient power during the ramp-up phase of the program. Step 210 also includes checking whether any probes are disabled. If any probes are disabled or at least one channel is in the ramp-up phase, the algorithm proceeds to step 220.

[0042] If none of the conditions of step 210 are met, the algorithm branches to step 300, which involves stopping the algorithm.

[0043] Step 220 includes determining whether the power is at its limit by checking whether the total power required by all probes is greater than the power that the generator can produce. The requested power for each channel is the power that the controller algorithm determines that the channel should receive to maintain the control (or target) temperature and minimize the temperature error. The controller defines the requested power for each channel based on the temperature error of the channel and the controller parameters assigned by the generator specific to the channel. Typically, the temperature error is the difference between the control temperature (i.e., the selected set point) and the measured temperature, where the temperature is typically measured by a sensor in the probe connected to the channel. In a typical embodiment of the system, the user can select the set point temperature and ramp time for each probe, and the system has default values ​​for the probe. Certain factors may affect the controller parameters applied to a specific channel, including probe size, probe type, and channel configuration (monopolar or bipolar). In the case of dual-probe bipolar energy delivery, each probe typically has a temperature sensor, and the temperature reading of the sensor with the higher temperature is read for control purposes.

[0044] Step 220 also includes checking whether the system is involved in an active multi-probe impairment (e.g., checking whether more than one probe is active) because the algorithm is designed to be used with at least two channels. The algorithm is intended for use with multiple RF cooled probes or multiple standard probe impairment modes. If only one probe is active or connected (single probe mode), steps 230 and 240 of the algorithm are not required. If only one probe is active or the generator is capable of producing more power, the algorithm branches to step 260 so that conditions can be checked to see if it is possible to re-enable the probe (steps 260 to 290 are performed to check if conditions are met to re-enable a disabled probe).

[0045] Step 230 includes checking whether the temperature error in all active channels in the ramp is greater than Y degrees (preset temperature error) within Z seconds, where "Y degrees" and "Z seconds" are parameters that are typically preset in the system. In some alternative embodiments of the system, these parameters may be selected by the user. Meeting this condition indicates that the active channels are not being provided with enough power for the channels to achieve the programmed ramp rate due to an underpower condition.

[0046] Step 240 includes checking that no channel has been disabled, enabled, or stopped by the user within the last X seconds (first system reaction time), where "X seconds" is a parameter that is typically preset in the system. In some alternative embodiments of the system, this parameter may be selected by the user. This check helps provide or ensure sufficient time for the system to adapt to changes in conditions.

[0047] Step 250 includes disabling a channel. If the conditions of steps 210 to 240 are met, the channel in the ramp-up phase is disabled and all active channels (which are in the ramp-up) use minimum power. In an alternative embodiment of the method, step 250 includes disabling the channel using the maximum power among all active channels or disabling another channel. After step 250, the algorithm loops back (returns) to step 210.

[0048] Enable a disabled channel

[0049] Regarding steps 260 to 290 ( Figure 2 ) The following conditions described by determine when the system can re-enable the most recently disabled channel without affecting other active channels. As described above, the algorithm branches from step 220 to step 260.

[0050] Step 260 includes checking that at least one channel is currently disabled by the algorithm, as typically only currently disabled channels that have been previously disabled by the generator / algorithm are re-enabled. In a typical embodiment of the algorithm, the algorithm does not re-enable channels that have been disabled by user intervention.

[0051] Step 270 includes checking whether any channel has been disabled, enabled, or stopped by the user within the last second system reaction time of XX seconds, where "XX seconds" is a parameter that is usually preset in the system. In some alternative embodiments of the system, this parameter can be selected by the user. If no channel has been disabled, enabled, or stopped within the specified time, the algorithm proceeds to step 280. The reason for this test is to provide the system with enough time to adapt to the change in conditions.

[0052] The purpose of step 280 is to check whether the system currently has enough power to activate another channel. Step 280 includes checking this using the following formula:

[0053] Total power (currently used by all active channels) < (P total -YY×system waiting time enabling P in ZZ seconds last ),in:

[0054] (a)P total is the total requested power in all channels at time T,

[0055] (b) YY is a safety factor margin used to buffer available power to avoid underpower conditions where the value of YY is greater than 1. For example, YY = 1.3 provides a 30% buffer, and YY = 1.2 provides a 20% buffer;

[0056] (c)P last is the final output power of the channel disabled at time T;

[0057] (d) time T is the time at which the most recently disabled and currently unenabled channel was closed; and

[0058] (e) ZZ is the system waiting time enabling System waiting time enabling Is the period of time the system waits after any state change before enabling another channel. The purpose of having a system wait time is to provide system stability.

[0059] In a typical embodiment, P total is the total requested power in all channels. In some alternative embodiments, P total is the total power used in all channels (which is the same as the total output power). In some other alternative embodiments, P total is the maximum output power.

[0060] If the test / check of steps 260 to 280 is positive, the algorithm proceeds to step 290. Step 290 comprises enabling the channel previously disabled in step 250. In a typical embodiment, the channel enabled is the channel that was most recently disabled. This step may also be described as re-enabling or restarting because the channel was previously enabled before being disabled. In some alternative embodiments, the channel enabled is the first disabled channel. In other alternative embodiments, the channel enabled may be a channel other than the first or last disabled channel, such as a random channel. After step 290, the algorithm returns to step 210 (as described above).

[0061] Alternative embodiments of the algorithm

[0062] In a first alternative embodiment, the algorithm is simplified by changing the test of step 230 (checking if the temperature error in all active channels in the ramp-up is greater than Y degrees for Z seconds) to a test of "checking if the power is at its limit for Z' seconds", which is usually used to check if the total requested power of all channels is greater than the output power limit of the generator for a period of Z' seconds. The situation where the generator is at its highest capacity for a period of time may indicate that the generator cannot provide enough power to supply the requested power.

[0063] In a second alternative embodiment, by testing step 280 "total power (currently used by all active channels) is less than Ptotal -YY× system waiting time enabling P in ZZ seconds last ” is changed to test “the total power used by all active channels is less than the power level threshold YY′ watts” to simplify the algorithm. There is more than one way to determine the power level threshold YY′. YY′ can be calculated using the formula YY′=P_max-P_avg_cannula, where P_max=the maximum output power of the system and P_avg_cannula=the average of the peak powers that all sleeve models (or cooling probe models) need to reach their nominal set temperature. YY′ can also be calculated using the formula YY′=P_max-P_max_cannula, where P_max_cannula=the peak power that all sleeve models (or cooling probe models) need to reach their nominal set temperature.

[0064] In a third alternative embodiment, the algorithm is simplified by omitting step 230 of checking whether the temperature error in all active channels in the ramp-up is greater than Y degrees for Z seconds.

[0065] In a fourth alternative embodiment, step 220 is simplified by removing one of the conditional checks. Specifically, the test for "total requested power > power limit" is removed from step 220, leaving a test that checks for multi-probe impairment by determining if "more than one probe is active."

[0066] In a fifth alternative embodiment, step 230 is changed by removing "ramp up" from the test, so that the test "whether the temperature error in all active channels in the ramp up is greater than the preset temperature error Y degrees within Z seconds" is changed to "the temperature error in all active channels is greater than the preset temperature error Y degrees within Z seconds." In other words, the test is expanded to include channels that are not ramped up.

[0067] In a sixth alternative embodiment, step 230 is changed by removing "ramp up" from the test, and using the average value of the temperature error, so that the test "whether the average temperature error in all active channels in the ramp up is greater than the preset temperature error Y degrees within Z seconds" is changed to "the temperature error in all active channels is greater than the preset temperature error Y degrees within Z seconds".

[0068] The changes of the above-mentioned first, second, third, fourth, fifth and sixth alternative embodiments may be implemented individually or in feasible combinations, for example, the first and third alternative embodiments are usually not implemented at the same time.

[0069] Other Examples

[0070] 1. A method of delivering energy to at least two electrosurgical probes connected to at least two channels of a generator, wherein the generator has a maximum output, the method comprising the steps of:

[0071] (a) activating the channel to be activated;

[0072] (b) checking for disabling conditions; and

[0073] (c) If a disabling condition exists, at least one of all active channels is disabled.

[0074] 2. The method of Example 1, wherein step (a) comprises activating the channels simultaneously.

[0075] 3. The method of example 1 or example 2, wherein step (b) comprises checking whether at least two electrosurgical probes are active.

[0076] 4. The method according to any one of Examples 1 to 3, wherein step (b) comprises checking whether at least one channel is in a ramp-up phase.

[0077] 5. The method according to any one of examples 1 to 4, wherein step (b) comprises checking whether the total requested power of all channels is greater than the maximum output of the generator.

[0078] 6. A method according to any one of Examples 1 to 5, wherein step (b) includes checking whether any channel has been disabled, enabled or stopped by a user within the first system reaction time.

[0079] 7. The method of any one of examples 1 to 6, wherein step (b) comprises checking whether the temperature error in all active channels in the ramp-up is greater than a preset temperature error.

[0080] 8. The method according to any one of examples 1 to 6, wherein step (b) comprises checking whether the temperature error of all active channels is greater than a preset temperature error.

[0081] 9. The method of any one of examples 1 to 8, wherein step (b) comprises checking whether the total requested power of all channels is greater than the output power limit of the generator for a period of time.

[0082] 10. The method of any one of examples 1 to 9, wherein step (c) comprises disabling a channel that occupies the least power among all active channels.

[0083] 11. The method of any one of examples 1 to 9, wherein step (c) comprises disabling a channel that occupies the most power among all active channels.

[0084] 12. The method of any one of examples 1 to 9, wherein step (c) comprises disabling all active channels except for a channel occupying the minimum power or the maximum power.

[0085] 13. The method of any one of examples 1 to 12, wherein step (c) comprises disabling one or more channels among all active channels.

[0086] 14. A method according to any one of Examples 1 to 13, wherein step (c) includes temporarily disabling the channel.

[0087] 15. The method according to any one of examples 1 to 14, further comprising a step (d) of checking an enabling condition.

[0088] 16. The method of example 15, further comprising the step (e) of re-enabling the most recently disabled channel if an enabling condition exists.

[0089] 17. A method according to example 15 or example 16, wherein step (d) includes checking whether there is at least one disabled channel.

[0090] 18. The method of any one of Examples 15 to 17, wherein step (d) comprises checking whether any channel has been disabled, enabled or stopped by a user within the second system reaction time.

[0091] 19. The method of any one of instances 15 to 18, wherein step (d) comprises checking whether the total power used by all active channels is less than (P total - Safety factor YY × system waiting time enabling P last ), where time T is the time when the most recently disabled and currently unenabled channel was closed, and where P total is the total requested power in all channels at time T, and where P last is the final output power of the channel disabled at time T.

[0092] 20. The method of any one of examples 15 to 19, wherein step (d) comprises checking whether the total power used by all active channels is less than a selected power level with a safety factor.

[0093] 21. An electrosurgical system for delivering energy to tissue, comprising:

[0094] a generator having a maximum output and at least two channels;

[0095] at least two probes operable to connect to the at least two channels such that the two channels are operable to deliver energy; and

[0096] A control system, when the at least two probes are connected to the at least two channels, the control system is operable to:

[0097] (a) activating the channel to be activated;

[0098] (b) checking for disabling conditions; and

[0099] (c) If a disabling condition exists, at least one of all active channels is disabled.

[0100] 22. An electrosurgical system according to Example 21, wherein the control system is operable to activate the channels simultaneously.

[0101] 23. An electrosurgical system according to Example 21 or Example 22, wherein the control system is operable to check whether at least two electrosurgical probes are active.

[0102] 24. An electrosurgical system according to any one of Examples 21 to 23, wherein the control system is operable to check whether at least one channel is in a ramp-up phase.

[0103] 25. An electrosurgical system according to any one of Examples 21 to 24, wherein the control system is operable to check whether the total requested power of all channels is greater than the maximum output of the generator.

[0104] 26. An electrosurgical system according to any of Examples 21 to 25, wherein the control system is operable to check whether any channel has been disabled, enabled, or stopped by a user within a first system reaction time.

[0105] 27. An electrosurgical system according to any one of Examples 21 to 26, wherein the control system is operable to check whether the temperature error in all active channels in the ramp-up is greater than a preset temperature error.

[0106] 28. An electrosurgical system according to any one of Examples 21 to 26, wherein the control system is operable to check whether the temperature error of all active channels is greater than a preset temperature error.

[0107] 29. An electrosurgical system according to any of Examples 21 to 28, wherein the control system is operable to check whether the total requested power of all channels is greater than the output power limit of the generator for a period of time.

[0108] 30. An electrosurgical system according to any one of Examples 21 to 29, wherein the control system is operable to disable the channel that consumes the least power among all active channels.

[0109] 31. An electrosurgical system according to any one of Examples 21 to 29, wherein the control system is operable to disable the channel that consumes the most power among all active channels.

[0110] 32. An electrosurgical system according to any one of Examples 21 to 29, wherein the control system is operable to disable all active channels except for the channel occupying the minimum power or the maximum power.

[0111] 33. An electrosurgical system as described in any of Examples 21 to 32, wherein the control system is operable to disable one or more channels among all active channels.

[0112] 34. An electrosurgical system according to any one of Examples 21 to 33, wherein the control system is operable to temporarily disable the channel.

[0113] 35. An electrosurgical system according to any one of Examples 21 to 34, wherein the control system is further operable to check an activation condition.

[0114] 36. An electrosurgical system as described in Example 35, wherein if an enabling condition exists, the control system is operable to re-enable a most recently disabled channel.

[0115] 37. An electrosurgical system according to Example 35 or Example 36, wherein the control system is operable to check whether at least one disabled channel exists.

[0116] 38. An electrosurgical system according to any of Examples 35 to 37, wherein the control system is operable to check whether any channel has been disabled, enabled or stopped by a user within a second system reaction time.

[0117] 39. An electrosurgical system according to any one of Examples 35 to 38, wherein the control system is operable to check whether the total power used by all active channels is less than (P total - Safety factor YY × system waiting time enabling P last ), where time T is the time when the most recently disabled and currently unenabled channel was closed, and where P total is the total requested power in all channels at time T, and where P last is the final output power of the channel disabled at time T.

[0118] 40. An electrosurgical system according to any of Examples 35 to 39, wherein the control system is operable to check whether the total power used by all active channels is less than a selected power level with a safety factor.

[0119] In another broad aspect, some embodiments of the disclosed method deliver energy to at least two electrosurgical probes connected to at least two channels of a generator, wherein the generator has a maximum output, the method comprising: (a) activating the channels; (b) checking for a disable condition; and (c) if the disable condition exists, disabling the channel that uses the least power among all active channels. Typically, step (a) includes activating the channels simultaneously. In alternative embodiments of the method, step (c) includes disabling the channel that uses the most power among all active channels or disabling another channel.

[0120] In another broad aspect, some embodiments of the disclosed electrosurgical system deliver energy to tissue using components that include: a generator having a maximum output and at least two channels; at least two probes operable to connect to the at least two channels so that the two channels are operable to deliver energy; and a control system operable to (a) activate a channel to be activated when the at least two probes are connected to the at least two channels; (b) check for a disable condition; and (c) if the disable condition exists, disable the channel using the least power among all active channels. Typically, step (a) includes activating the channels simultaneously. In alternative embodiments of the system, step (c) includes disabling the channel using the most power among all active channels or disabling another channel.

[0121] Although the description herein focuses primarily on the use of the system in neurotomy procedures, the disclosed methods and apparatus are relevant to and can be used in other procedures including tumor ablation procedures.

[0122] The above embodiments are exemplary only. Therefore, the scope of the present invention is limited only by the scope of the appended claims.

[0123] Although the present invention has been described in conjunction with its specific embodiments, it is apparent that many replacements, modifications and variations are apparent to those skilled in the art. Therefore, the present invention is intended to include all of these replacements, modifications and variations that fall within the broad scope of the appended claims. All publications, patents and patent applications mentioned in this specification are incorporated by reference in their entirety into this specification, to the extent that each individual publication, patent or patent application is specifically and individually indicated to be incorporated by reference herein. In addition, the citation or identification of any reference in this application should not be construed as admitting that these references can be used as prior art of the present invention.

[0124] It should be understood that the various aspects disclosed herein can be combined in combinations different from those specifically presented in the specification and drawings. It should also be understood that, depending on the embodiment, certain actions or events in any process or method described herein can be performed in a different order, can be added, merged, or completely ignored (e.g., not all described actions or events are necessary to implement the technology). In addition, although certain aspects of the present disclosure are described as being performed by a single module or unit for clarity, it should be understood that the technology of the present disclosure can be performed by a combination of units or modules associated with, for example, a medical device.

[0125] In one or more examples, the described techniques may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored as one or more instructions or codes on a computer-readable medium and executed by a hardware-based processing unit. A computer-readable medium may include a non-transitory computer-readable medium, which corresponds to a tangible medium, such as a data storage medium (e.g., RAM, ROM, EEPROM, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and can be accessed by a computer).

[0126] Instructions may be executed by one or more processors, such as one or more digital signal processors (DSPs), general purpose microprocessors, application specific integrated circuits (ASICs), field programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuits. Thus, the term "processor" as used herein may refer to any of the foregoing structures or any other physical structure suitable for implementing the described techniques. Moreover, the techniques may be fully implemented in one or more circuits or logic elements.

Claims

1. A computer readable medium comprising instructions stored thereon, which when executed by a processing unit causes the processing unit to perform a method of delivering energy to at least two electrosurgical probes connected to at least two channels of a generator, wherein the generator has a maximum output, the method comprising the steps of: (a) activating at least one channel of the at least two channels to be activated; (b) Check for disabling conditions; as well as (c) if a disable condition associated with an underpower condition of the generator exists, disabling at least one of the at least two channels from all active channels, wherein the disabled channel does not deliver energy.

2. The computer-readable medium of claim 1, wherein step (a) comprises activating all of the at least two channels simultaneously.

3. The computer readable medium of claim 1 or claim 2, wherein step (b) comprises checking whether at least two electrosurgical probes are active.

4. The computer-readable medium according to any one of claims 1 to 2, wherein step (b) comprises checking whether at least one of the at least two channels is in a ramp-up phase.

5. The computer readable medium of any one of claims 1 to 2, wherein step (b) comprises checking whether a total requested power of all channels of the at least two channels is greater than the maximum output of the generator.

6. The computer readable medium of any one of claims 1 to 2, wherein step (b) comprises checking whether any channel has been disabled, enabled or stopped by a user within the first system reaction time.

7. The computer-readable medium of any one of claims 1 to 2, wherein step (b) comprises checking whether the temperature error in all active channels in the ramp-up is greater than a preset temperature error.

8. The computer-readable medium according to any one of claims 1 to 2, wherein step (b) comprises checking whether the temperature error of all active channels is greater than a preset temperature error.

9. The computer readable medium of any one of claims 1 to 2, wherein step (b) comprises checking whether the total requested power of all channels of the at least two channels is greater than the maximum output of the generator for a period of time.

10. The computer-readable medium of any one of claims 1 to 2, wherein step (c) comprises disabling a channel of the at least two channels that occupies the least power from all active channels.

11. The computer-readable medium of any one of claims 1 to 2, wherein step (c) comprises disabling a channel of the at least two channels that occupies the most power from all active channels.

12. The computer-readable medium of any one of claims 1 to 2, wherein step (c) comprises disabling channels of the at least two channels except for a channel occupying a minimum power or a maximum power from all active channels.

13. The computer-readable medium of any one of claims 1 to 2, wherein step (c) comprises disabling one or more of the at least two channels from all active channels.

14. The computer-readable medium of any one of claims 1 to 2, wherein step (c) comprises temporarily disabling a channel of the at least two channels.

15. The computer-readable medium according to any one of claims 1 to 2, wherein: The method further comprises the step (d) of checking an enabling condition.

16. The computer readable medium of claim 15, further comprising the step of re-enabling the most recently disabled channel if an enable condition exists.

17. The computer-readable medium of claim 15, wherein step (d) comprises checking whether there is at least one disabled channel among the at least two channels.

18. The computer-readable medium of claim 15, wherein step (d) comprises checking whether any of the at least two channels has been disabled, enabled, or stopped by a user within the second system reaction time.

19. The computer-readable medium of claim 15, wherein step (d) comprises checking whether the total power used by all active channels is less than (P total - Safety factor YY × system waiting time enabling P last ), where time T is the time when the most recently disabled and currently unenabled channel was closed, and where P total is the total requested power in all channels at time T, and where P last is the final output power of the channel disabled at time T, where the system waits for enabling is the period of time that the system waits after any state change before enabling another channel, and the safety factor YY is the margin used to buffer the available power to avoid power shortage conditions.

20. The computer-readable medium of claim 15, wherein step (d) comprises checking whether the total power used by all active channels is less than a selected power level with a safety factor.

21. An electrosurgical system for delivering energy to tissue, comprising: a generator having a maximum output and at least two channels; at least two probes operable to connect to the at least two channels such that the two channels are operable to deliver energy; as well as A control system, when the at least two probes are connected to the at least two channels, the control system is operable to: (a) activating at least one channel of the at least two channels to be activated; (b) Check for disabling conditions; as well as (c) if a disable condition associated with an underpower condition of the generator exists, disabling at least one of the at least two channels from all active channels, wherein the disabled channel does not deliver energy.

22. An electrosurgical system as recited in Claim 21, wherein the control system is operable to activate all of the at least two channels simultaneously.

23. An electrosurgical system according to claim 21 or claim 22, wherein the control system is operable to check whether at least two electrosurgical probes are active.

24. An electrosurgical system according to any one of claims 21 to 22, wherein the control system is operable to check whether at least one of the at least two channels is in a ramp-up phase.

25. An electrosurgical system according to any one of claims 21 to 22, wherein the control system is operable to check whether the total requested power of all of the at least two channels is greater than the maximum output of the generator.

26. An electrosurgical system according to any one of claims 21 to 22, wherein the control system is operable to check whether any channel has been disabled, enabled or stopped by a user within a first system reaction time.

27. An electrosurgical system according to any one of claims 21 to 22, wherein the control system is operable to check whether the temperature error in all active channels in the ramp-up is greater than a preset temperature error.

28. An electrosurgical system according to any one of claims 21 to 22, wherein the control system is operable to check whether the temperature error of all active channels is greater than a preset temperature error.

29. An electrosurgical system according to any one of claims 21 to 22, wherein the control system is operable to check whether the total requested power of all of the at least two channels is greater than the maximum output of the generator for a period of time.

30. An electrosurgical system according to any one of Claims 21 to 22, wherein the control system is operable to disable the least powered of the at least two channels from among all active channels.

31. An electrosurgical system according to any one of claims 21 to 22, wherein the control system is operable to disable the channel of the at least two channels occupying the most power from all active channels.

32. An electrosurgical system according to any one of claims 21 to 22, wherein the control system is operable to disable channels of the at least two channels except for the channel occupying minimum power or maximum power from all active channels.

33. An electrosurgical system according to any one of claims 21 to 22, wherein the control system is operable to disable one or more of the at least two channels from all active channels.

34. An electrosurgical system according to any one of Claims 21 to 22, wherein the control system is operable to temporarily disable a channel of the at least two channels.

35. An electrosurgical system according to any one of Claims 21 to 22, wherein the control system is further operable to check an enabling condition.

36. An electrosurgical system as described in Claim 35, wherein the control system is operable to re-enable a most recently disabled channel if an enable condition exists.

37. An electrosurgical system as recited in Claim 35, wherein the control system is operable to check for the presence of at least one disabled channel of the at least two channels.

38. An electrosurgical system as recited in Claim 35, wherein the control system is operable to check whether any of the at least two channels has been disabled, enabled, or stopped by a user within a second system reaction time.

39. An electrosurgical system according to claim 35, wherein the control system is operable to check whether the total power used by all active channels is less than (P total - Safety factor YY × system waiting time enabling P last ), where time T is the time when the most recently disabled and currently unenabled channel was closed, and where P total is the total requested power in all channels at time T, and where P last is the final output power of the channel disabled at time T, where the system waits for enabling is the period of time that the system waits after any state change before enabling another channel, and the safety factor YY is the margin used to buffer the available power to avoid power shortage conditions.

40. An electrosurgical system as recited in Claim 35, wherein the control system is operable to check whether the total power used by all active channels is less than a selected power level with a safety factor.

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