Resistance level communication protocol

Abstract

An electrosurgical system includes a generator and an electrosurgical device, and is configured to establish bidirectional communication using a resistive level communication protocol. The electrosurgical device includes: an electrical connector configured to receive a treatment signal and a continuous signal from a generator; an AC-DC converter configured to convert the continuous signal, and an AC-DC converter configured to convert the continuous signal; a processor configured to receive the converted continuous signal; and a resistor connected to the processor and configured to vary a power current used by the processor over time. The generator is configured to interpret a change in current as data and provide confirmation to the electrosurgical device.

Description

Technical Field

[0001] This application includes subject matter related to U.S. Patent Application No. 18 / 083,287. The entire disclosure of the above application is incorporated herein by reference.

[0002] Embodiments of the present disclosure generally relate to the field of electrosurgical energy delivery and, more particularly, to a resistance-level communication protocol for communication between an electrosurgical handpiece and an electrosurgical generator. Background Art

[0003] Electrosurgical devices for applying electrical energy to tissue are typically used in surgical procedures for hemostatic sealing and coagulation of soft tissue and bone at a surgical site. Such electrosurgical devices can be used in, but are not limited to, plastic surgery, spinal surgery, thoracic surgery, and abdominal surgery.

[0004] An electrosurgical device can include a handpiece having a distal mounting end that includes one or more electrodes. The one or more electrodes can be positioned against tissue such that current is introduced into the tissue. The heat generated can be used to cut, coagulate, or induce metabolic processes in the target tissue. An electrosurgical generator typically provides power and electrical energy in the form of radio frequency (“RF”) energy to one of a monopolar and bipolar handpiece topology.

[0005] The handpiece can include one or more buttons for energy activation. Typically, the internal digital circuitry in an electrosurgical generator is isolated from the front end of the generator, and thus the generator uses a low-frequency signal with an isolation transformer to detect the button status of the handpiece. Conventional methods for powering the handpiece typically use a specific level of resistance to detect a high resistance indicating that a button is released and a low resistance indicating that a button is pressed.

[0006] Conventional electrosurgical handpieces for electrosurgical tissue treatment cannot establish communication with an electrosurgical generator and thus face several challenges. Some of the challenges that arise include the inability to determine the manufacturer and model of the electrosurgical handpiece and the usage time. Understanding device-specific information about the electrosurgical handpiece coupled to the generator is beneficial for safe and consistent treatment delivery.

[0007] Accordingly, improved systems and methods are desired to enhance the communication capabilities of electrosurgical devices without modifying the generator or requiring a second electrical connection to the electrosurgical device. Summary of the Invention

[0008] The technology of the present disclosure generally relates to an electrosurgical device configured to communicate with an electrosurgical generator using existing button press signals to formulate a resistance-level communication protocol to increase the functionality of the electrosurgical device without requiring any changes to the wiring of the electrosurgical generator.

[0009] In one aspect, the present disclosure provides a system configured to establish two-way communication using a resistive-level communication protocol. The system includes a generator and an electrosurgical device. The electrosurgical device includes: an electrical connector configured to receive a treatment signal and a continuous signal from the generator; an AC-DC converter configured to convert the continuous signal into a DC signal; a processor configured to receive the DC signal; and a resistor connected to the processor and configured to vary the power current used by the processor over time. The generator is configured to interpret the variation in current as data and provide an acknowledgement to the electrosurgical device using frequency shift keying (FSK).

[0010] In another aspect, the present disclosure provides a method for two-way communication between an electrosurgical device and a generator. The method includes providing a continuous signal from the generator to the electrosurgical device. Then, at the electrosurgical device, the continuous signal is converted into a DC signal, the converted signal is used to power the processor, a resistor is used to vary the power current used by the processor over time, and the current is provided to the generator. The method further includes: interpreting the variation in the changed current as data at the generator and sending an acknowledgement to the electrosurgical device using frequency shift keying (FSK).

[0011] Details of one or more aspects of the present disclosure are set forth in the following drawings and description. Other features, objects, and advantages of the techniques described in the present disclosure will be apparent from the description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The subject matter of the present invention can be more fully understood when the following detailed description of various embodiments is considered in conjunction with the accompanying drawings, in which:

[0013] Figure 1 is a schematic diagram depicting an electrosurgical device according to the prior art.

[0014] Figure 2 is a schematic diagram depicting an electrosurgical device according to an embodiment.

[0015] Figure 3 is a graph showing the variation of the resistance of an electrosurgical device circuit over time according to an embodiment.

[0016] Figure 4 is a graph showing the variation of the resistance of an electrosurgical device circuit over time represented as binary values according to an embodiment.

[0017] Figure 5 is a schematic diagram depicting an electrosurgical device according to an embodiment.

[0018] Figure 6 is a schematic diagram depicting an electrosurgical device according to an embodiment.

[0019] Figure 7 is a schematic diagram depicting an electrosurgical device according to an embodiment.

[0020] Figure 8 is a flowchart of a method for interactive encryption according to an embodiment.

[0021] Figure 9 is a flowchart of a method for two-way communication between an electrosurgical device and a generator according to an embodiment.

[0022] While various embodiments may adopt various modifications and alternative forms, details thereof have been shown by way of example in the drawings and will be described in detail. However, it should be understood that the intention is not to limit the claimed invention to the specific embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the subject matter as defined by the claims. Detailed Description

[0023] Figure 1 is a partial schematic diagram of an electrosurgical device 100 configured to transmit RF energy at a treatment site to provide hemostatic sealing and coagulation of soft tissue and bone. The electrosurgical device 100 includes a connector 102 and a bipolar handpiece 104 having two electrodes 106.

[0024] The connector 102 includes a large pin 108 and a small pin 110 and is configured to be in electrical communication with an electrosurgical generator (not shown) and the proximal end of the bipolar handpiece 104 such that a power signal is delivered to the electrodes 106 at the distal end of the bipolar handpiece 104. In an embodiment, the connector 102 may be a 3-pin connector capable of providing a high-power treatment signal and a low-power continuous signal via a cable 114. The large pin 108 is for the high-power treatment signal, while the small pin 110 uses the low-power continuous signal to detect button presses on the handpiece. When the button is pressed, the circuit is closed by a switch 112 and a treatment signal is provided. In an embodiment, examples of the treatment signal are 469 KHz and 20 W to 220 W, while an example of the continuous signal is 47 KHz.

[0025] It should be understood that the terms "proximal" and "distal" as used herein are with reference to a clinician grasping the handpiece. Thus, the electrodes 106 are distal relative to the closer proximal handle or grasping portion of the bipolar handpiece 104. However, the surgical device is used in many orientations and positions, and these terms are not intended to be restrictive and absolute.

[0026] Figure 2Depicts a schematic diagram of an electrosurgical device 200 configured to transmit device data to an electrosurgical generator using an RF signal for detecting button presses. The transmitted device data may include one or more of a device ID, the cumulative usage time of the device, manufacturing information, and waveform information.

[0027] The electrosurgical device 200 includes a connector 202 and a bipolar handpiece 204 having two electrodes 206, a switch 212, wires 214, a transformer 216, a digital potentiometer 218, and a controller 220. The connector 202 includes a large pin 208 and a small pin 210 and is configured to be compatible with an existing electrosurgical power supply or a bipolar energy source. For example, crosslinking (transcollation) sealing energy provided by a system (available from Medtronic Advanced Energy of Portsmouth, N.H.) may be used. U.S. Patent Nos. 6,558,385, 6,702,810, 6,953,461, 7,115,139, 7,311,708, 7,537,595, 7,645,277, and 7,811,282 also describe bipolar ablation energy systems suitable for embodiments of the present disclosure.

[0028] Accordingly, the electrosurgical device 200 is connected to an electrical energy source via the connector 202. Since the connector 202 is designed to be compatible with a previously existing generator, the pins are standardized based on the desired generator. In an embodiment, more or fewer large pins and short pins may be used depending on the requirements of the generator. In an embodiment, the small pin 210 is used to detect button activation. Button press detection may be performed by monitoring the resistance level of a low-power signal generated by the electrosurgical generator. For example, the electrosurgical generator may inject a 47 KHz low-power signal between one of the large pins 208 and the small pin 210 and continuously monitor the resistance between the two pins (e.g., every 1 millisecond). If the detected resistance is less than a threshold resistance, the electrosurgical generator may determine that the button is pressed and the switch 212 is closed, otherwise it may determine that the button is released and the switch 212 is open. In an embodiment, the threshold resistance is 400 ohm.

[0029] The current reading at the generator does not have a linear relationship with the resistance threshold. Accordingly, the appropriate resistance threshold should be determined based on the minimum resistance.

[0030] In an embodiment, the generator can detect the resistance between a first pin connected to one side of the button and a second pin connected to the other side of the button. In such an embodiment, the third pin will be connected to electrode 206. The analog-to-digital converter (ADC) inside the generator is configured to convert the detected resistance into a digital count (e.g., for a 12-bit ADC, the conversion will be from 0 to 4095 counts). Then, the processor of the generator is configured to consider any reading equal to or higher than a threshold count as the button being pressed, and any reading less than the threshold count as the button being released. The count represents the current passing through the button, so the lower the resistance, the higher the count. The threshold count is defined as R min . In an embodiment, R min can be 1000 counts. In such an embodiment, each reading between 0 count and 999 counts can be considered an open circuit, although the actual number may be available.

[0031] Adding a parallel resistor (such as digital potentiometer 218 isolated by transformer 216) effectively makes the total resistance between the first pin and the second pin a combination of the two resistors. The total resistance can be expressed as:

[0032]

[0033] In this arrangement, when the button is pressed, R 总 is effectively 0, such that button press detection is effectively equivalent to an electrosurgical device without additional circuitry. However, when the button is released, R 总 equals R DP . If R DP is adjusted to be less than R min , the generator will activate the handpiece without pressing the button. Therefore, the resistance value of the digital potentiometer should be avoided from being less than R min to prevent accidental activation of the electrosurgical device. In practice, a margin should be added to R min to ensure user safety. Therefore, R 低 can be equal to R min and R 裕度的总和 , while R 高 is the maximum resistance that can be adjusted by the digital potentiometer. Therefore, R Figure 3 can be configured as a graph of R 总 versus time as shown.

[0034] When the button is released, the generator will be able to detect the value between R 低 and R 高 , and if the value of R DP is encoded by the controller 220 using a digital message, the generator will be able to receive the message.

[0035] ReferenceFigure 4 , which depicts the change in resistance of a digital potentiometer (such as digital potentiometer 218 corresponding to digital data) over time. In an embodiment, when a button of an electrosurgical device is pressed, the generator resistance reading is not defined in terms of communication, and the resistance will only be regarded as button detection.

[0036] Although as Figure 4 shown, the rise and fall of the resistance theoretically occur immediately, but in reality, the value of the digital potentiometer cannot change immediately, and the rise time and fall time must be considered. In an embodiment, one-third of the resistance range (R 低 -R 高 ) starting from the highest resistance will be considered the digital high threshold R High_Th , and one-third of the resistance range starting from the lowest resistance is considered the digital low threshold R Low_Th . The value between R High_Th and R High_Low can be considered undefined. In an embodiment, up to half of the values in the resistance range can be used as digital thresholds for interpreting communication. However, it is generally preferred that some resistance ranges are not defined to better distinguish digital data. In an embodiment, R High_Th can be one-fourth of the resistance range below R 高 , while R Low_Th can be one-fourth of the resistance range above R 低 .

[0037] To prevent the occurrence of an undefined state, the communication protocol can allow sufficient time for the resistance level to change between a high level and a low level. The stack code of the communication protocol can consider multiple readings over a period of time to ensure that the level is stable. In an embodiment, the period of time can be defined as 10 times the longer of the rise time and the fall time, and will depend on the components used for the digital potentiometer.

[0038] Over time, the controller within the electrosurgical device can change the resistance of the digital potentiometer by mode to transmit device data. In an embodiment, the transmitted device data can include a mode representing the device ID, and then the cumulative usage time. The read range must consider unauthorized areas to prevent unintentional activation. If R DP is adjusted to be less than R min , the generator will activate the handpiece without pressing the button. Therefore, any value less than R min is the unauthorized area of the digital potentiometer.

[0039] Accordingly, the resistance-level communication protocol of the present disclosure enables a peer-to-peer unilateral communication hardware protocol by converting the resistance of a button press signal into digital data without affecting the primary function of the wires used. It is noted that the definition of the resistance-level communication protocol is not limited to using different resistance variations when considering a resistive open circuit for the primary function. This method is merely one way of using the protocol through a hardware parallel digital potentiometer topology. For example, in an embodiment, different resistance variations can be used when considering a resistive closed circuit for the primary function. Additionally, alternative actuation controls such as sliders, switches, or other input mechanisms can be used in place of the button to open and close the circuit.

[0040] Accordingly, embodiments of the present disclosure provide a resistance-level communication protocol to enable communication between an electrosurgical handpiece and an electrosurgical generator. As a result of this communication, the electrosurgical generator can receive data from the electrosurgical handpiece to identify the type of device connected to the bipolar port and other device information. If the electrosurgical device is not recognized, this device identification can cause the electrosurgical generator to prevent operation, thereby enhancing safety by restricting use to known equipment and operating parameters.

[0041] The resistance-level communication protocol can be effectively implemented with only minimal changes to the handpiece without changing the hardware of the electrosurgical generator. The hardware changes to the electrosurgical handpiece do not introduce new wiring from the electrosurgical device 200, thus causing no trouble during operation and storage. Further, since no hardware changes are required to the electrosurgical generator, the resistance-level communication protocol can be extended to pre-existing electrosurgical generators via software updates.

[0042] Alternative arrangements of the electrosurgical device 200 are shown in Figure 5 and Figure 6 . These arrangements introduce a digital potentiometer in series with the main line and the primary function device and utilize the lower side of the resistance. These arrangements can be used if, for the majority of the time, the main application represents a short circuit. For an electrosurgical handpiece or device where the button is pressed most of the time, it is more reasonable to utilize the resistance range when the button is pressed for the ADC inside the generator to detect the communication signal, as this can provide a longer period for the transmission of device data. As shown in Figure 5 , placing the digital potentiometer in series makes this communication possible. Figure 6 depicts a hybrid mode of the resistance communication-level protocol that utilizes communication when the button is pressed and released by having two digital potentiometers and a controller.

[0043] In an embodiment, the controller 220 can measure the button signal impedance by measuring current instead of resistance, and thereby obtain power. Such an embodiment can enhance the microcontroller recording function and can be implemented with a single resistor by the controller 220, thus eliminating the need for an isolation transformer. If the controller in the circuit does not include other components, the frequency range available for transmitting device data is relatively limited. This reduction in range is due to the increased resistance of the controller. In such an embodiment, the reduced frequency range is sufficient to operate with the resistance-level communication protocol described in the present disclosure.

[0044] One disadvantage of unidirectional communication is that the communication signal can be replicated by different circuits, thus introducing a security issue. To address this problem, encryption can be implemented from the electrosurgical handpiece to the generator, but this first requires a handshake (bidirectional communication). The inventors of the present disclosure have discovered a mechanism for creating communication from the generator to the electrosurgical device that can be used as a handshake for the resistance-level communication protocol.

[0045] Figure 7 A schematic diagram of an electrosurgical device 300 configured to facilitate bidirectional communication with an electrosurgical generator is depicted. The electrosurgical device 300 includes a connector 302 and a bipolar handpiece 304 having two electrodes 306, a switch 312, wires 314, an AC-DC converter 316, a processor 318, and a resistor 320. The connector 302 includes a large pin 308 and a small pin 310 and is configured to be compatible with an existing electrosurgical power supply or bipolar energy supply.

[0046] As previously described, the generator uses a signal to detect when the button is pressed, and this signal is the same as the signal used for the resistance-level communication protocol DC power (extracted energy) and the signal for resistance measurement. Neither the generator nor the electrosurgical device 300 depends on the frequency of the button signal, which means that small changes in the frequency of the button detection signal will not change the button detection, the resistance-level communication protocol power, and the function of the resistance-level communication protocol. For example, if the generator typically uses a 47KHz signal to detect button presses, this frequency can be changed to 40KHz instead of 47KHz without interrupting operation. The cut-off frequency of the circuit should be checked to determine the range within which the button detection frequency can be manipulated without affecting operation.

[0047] The button press detection frequency is generated inside the generator from a complex programmable logic device (CPLD) or a field programmable gate array (FPGA). The processor communicates continuously with the CPLD and can notify the CPLD to use a frequency different from the standard operating frequency. Thus, the implementation of changes in the button press detection frequency can be changed through a software update, enabling bidirectional communication to be used with pre-existing generators.

[0048] Techniques for sending digital data by varying the frequency are known as frequency shift keying (FSK). An FSK receiver can be a simple counter that measures the frequency and converts the frequency into data. The counter can be as simple as a pin of processor 318, where a shaping (limiting) circuit 322 converts the sine wave into a square wave. Using this method, two-way communication can be established.

[0049] The high and low level resistances of resistor 320 cause current variations in the power consumption of processor 318 from AC-DC converter 316. As a result, these high and low level resistances can be converted into currents sensed in the generator to implement a resistive level communication protocol.

[0050] Interactive encryption in the acknowledgement message from the generator can be implemented using electrosurgical device 300. Figure 8 A flowchart of method 400 for such interactive encryption according to an embodiment is depicted. Method 400 applies a function to the device ID of the electrosurgical device to create encrypted data. Since the encryption method and the encryption output depend on the device ID, they will vary.

[0051] At 402, the first part (e.g., the first 8 bits) of the device ID is read. In an embodiment, different device-specific static data can be used instead of the device ID.

[0052] At 404, the first part of the device ID can be used to define what encryption algorithm will be used.

[0053] At 406, the selected encryption algorithm is applied to the device ID.

[0054] At 408, the output of the selected encryption algorithm from 406 is truncated to fit a reduced number of bytes. In an embodiment, the output is truncated to fit 2 bytes. This size reduction brings the possibility that the plaintext data decrypted from the encrypted data may not be unique. Since the goal of this encryption is to confirm known plaintext data, it is beneficial to make it non-recoverable.

[0055] Method 400 can output plaintext data that is known to both the electrosurgical device and the generator. This simplifies the handshake to a simple comparison of the outputs from each device. Thus, method 400 provides double-encrypted data that is interactively bound to the plaintext data because the encryption method itself is also encrypted.

[0056] Reference Figure 9 , a flowchart of electrosurgical device operation 500 and generator operation 502 for implementing method 400 according to an embodiment is depicted.

[0057] At 504, the electrosurgical device sends the device ID to the generator using a resistive-level communication protocol.

[0058] At 506, the generator receives the device ID via the resistive-level communication protocol.

[0059] At 508, the generator determines whether the device ID is correct.

[0060] If the device ID is incorrect, an error is displayed to the user or otherwise reported at 510.

[0061] If the device ID is correct, at 512, the generator uses FSK to send an encrypted response and real-time communication (RTC) to the electrosurgical device. Sending this information serves as confirmation of the device ID.

[0062] At 514, the electrosurgical device receives the confirmation.

[0063] At 516, the electrosurgical device determines whether the electrosurgical device has expired.

[0064] If the electrosurgical device has not expired, at 518, the electrosurgical device determines whether the confirmation is correct. If the confirmation is correct, the electrosurgical device returns to 504 and continues to report device data.

[0065] If the electrosurgical device has expired, at 520, the electrosurgical device intentionally sends an incorrect device ID to the generator using the resistive-level communication protocol.

[0066] At 522, the generator receives the incorrect device ID via the resistive-level communication protocol.

[0067] At 524, an error is displayed to the user or otherwise reported. In an embodiment, the incorrect device ID can be a specific code that is configured to cause a unique error such that the user can be made aware that the electrosurgical device has expired.

[0068] 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 example, certain actions or events of any of the processes or methods described herein can be performed in a different order, can be added, combined, or omitted entirely (e.g., not all of the described actions or events may be required to perform these techniques). Additionally, 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 techniques of the present disclosure can be performed by a combination of units or modules associated with, for example, a medical device.

[0069] 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 on a computer-readable medium as one or more instructions or code and executed by a hardware-based processing unit. The computer-readable medium may include non-transitory computer-readable media corresponding to tangible media such as data storage media (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 that can be accessed by a computer).

[0070] The instructions may be executed by one or more processors, such as one or more digital signal processors (DSPs), general microprocessors, application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other equivalent integrated or discrete logic circuitry. Thus, as used herein, the term “processor” may refer to any of the foregoing structures or any other physical structure suitable for implementing the described techniques. Additionally, these techniques may be fully implemented in one or more circuits or logic elements.

Claims

1. A system configured to establish two-way communication using a resistive-level communication protocol, the system comprising: A generator; And An electrosurgical device, the electrosurgical device comprising: An electrical connector configured to receive a treatment signal and a continuous signal from the generator; An AC-DC converter configured to convert the continuous signal into a DC signal; A processor configured to receive the DC signal; and A resistor connected to the processor and configured to change the power current used by the processor over time; Wherein the generator is configured to interpret the change in the current as data and provide an acknowledgement to the electrosurgical device using frequency shift keying (FSK).

2. The system according to claim 1, wherein the data is one or more of the following: device ID, cumulative usage time of the device, manufacturing information, and waveform information.

3. The system according to claim 1, wherein the acknowledgement is based on the data.

4. The system according to claim 3, wherein the acknowledgement includes the output of an encryption algorithm applied to the data.

5. The system according to claim 4, wherein the encryption algorithm is selected based on at least a portion of the data.

6. The system according to claim 1, wherein the acknowledgement is a set number of bytes.

7. The system according to claim 1, wherein the data is based on multiple readings of the current over a period of time.

8. The system according to claim 1, wherein the generator is further configured to limit the frequency of the treatment signal based on the data.

9. The system according to claim 1, wherein the generator is further configured to provide a warning that the electrosurgical device has expired based on the data.

10. A method for two-way communication between an electrosurgical device and a generator, the method comprising: Providing a continuous signal to the electrosurgical device via the generator, and at the electrosurgical device: Converting the continuous signal into a DC signal; Powering the processor with the DC signal; And Changing the power current used by the processor over time using a resistor; Providing the current to the generator via the electrosurgical device, and at the generator: Interpreting the change in the current as data; and Sending an acknowledgement to the electrosurgical device using frequency shift keying (FSK).

11. The method according to claim 10, wherein the data is one or more of the following: device ID, cumulative usage time of the device, manufacturing information, and waveform information.

12. The method according to claim 10, wherein the acknowledgement is based on the data.

13. The method according to claim 12, wherein the acknowledgement includes the output of an encryption algorithm applied to the data.

14. The method according to claim 13, wherein the encryption algorithm is selected based on at least a portion of the data.

15. The method according to claim 10, wherein the acknowledgement is a set number of bytes.

16. The method according to claim 10, wherein the data is based on a plurality of readings of the current over a period of time.

17. The method according to claim 10, wherein the generator is further configured to limit the frequency of the treatment signal provided to the electrosurgical device based on the data.

18. The method according to claim 10, wherein the method further comprises: The generator provides a warning that the electrosurgical device has expired based on the data.

19. A system configured to establish two-way communication using a resistive-level communication protocol, the system comprising: A generator; And An electrosurgical device, the electrosurgical device comprising: An electrical connector configured to receive a treatment signal and a continuous signal from the generator; A transformer configured to isolate the continuous signal; A digital potentiometer configured to receive the isolated continuous signal; and A controller configured to change the resistance of the digital potentiometer over time; Wherein the generator is configured to interpret the change in the resistance as data and provide an acknowledgement to the electrosurgical device using frequency-shift keying (FSK).

20. The system according to claim 19, wherein the data is one or more of the following: a device ID, the cumulative usage time of the device, manufacturing information, and waveform information.

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