Energy control device and treatment system

An energy control device for an ultrasonic treatment tool which includes an ultrasonic transducer and an end effector that performs a treatment using the ultrasonic vibration generated by the ultrasonic transducer comprises a first power supply configured to supply an electric power to the ultrasonic transducer, and a circuit. The circuit is configured to measure an output duration, monitor a characteristic parameter representing a situation of the treatment, set a time threshold value based on the characteristic parameter, and perform, when the output duration exceeds the time threshold value, at least one of: stopping or reducing the output of electric power from the first power supply to the ultrasonic transducer and notifying that the output duration has exceeded the time threshold value.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an energy control device for an ultrasonic treatment tool and a treatment system comprising the same.

2. Description of the Related Art

Known have been ultrasonic treatment tools having a pair of grasping pieces for grasping living tissue to be treated, one of the grasping pieces vibrating ultrasonically to promote coagulation, incision or the like of the living tissue being grasped. Continued vibration of the grasping pieces of this kind of ultrasonic treatment tools despite the treatment being completed and the living tissue being successfully incised is undesired. Vibration of the grasping pieces while in direct mutual contact may cause damage to the grasping pieces.

An example of such ultrasonic treatment tool is disclosed in International Publication No. 2015/122306. In this ultrasonic treatment tool, completion of the treatment is detected as follows. That is, electrical impedance of an ultrasonic transducer of the ultrasonic treatment tool is obtained. This impedance gradually increases and then gradually decreases. The ultrasonic treatment tool detects an excision of the grasped living tissue based on the impedance variation and adjusts the output.

BRIEF SUMMARY OF THE INVENTION

According to an aspect of the invention, an energy control device provides an electric power to an ultrasonic treatment tool. The ultrasonic treatment tool comprises an ultrasonic transducer that generates an ultrasonic vibration by being supplied with the electric power and an end effector that performs a treatment using the ultrasonic vibration generated by the ultrasonic transducer. The energy control device comprises a first power supply configured to supply the electric power to the ultrasonic transducer, and at least one circuit. The circuit is configured to measure an output duration related to a time during which the first power supply continues outputting, monitor a predetermined characteristic parameter representing a situation of the treatment, set a time threshold value based on the characteristic parameter, wherein the time threshold value is set sequentially based on the characteristic parameter monitored repeatedly until the output duration exceeds the time threshold value, and perform, when the output duration exceeds the time threshold value, at least one of: stopping or reducing the output of electric power from the first power supply to the ultrasonic transducer and notifying that the output duration has exceeded the time threshold value.

DETAILED DESCRIPTION OF THE INVENTION

First Embodiment

A first embodiment of the present invention will be described with reference to the drawings. The first embodiment relates to a treatment system for treating living tissue using ultrasonic vibration.

Treatment System Configuration

FIG. 1is a schematic view showing a treatment system1. As shown inFIG. 1, the treatment system1comprises an ultrasonic treatment tool2and an energy control device3that supplies power to the ultrasonic treatment tool2.

The ultrasonic treatment tool2comprises a housing5, a shaft6connected to the housing5, and an end effector7provided at the end of the shaft6. The side on which the end effector7is provided will be referred to as the distal end side and the side on which the housing5is provided will be referred to as the proximal end side. The housing5is provided with a grip11so that a user can hold the ultrasonic treatment tool2, and a handle12that is opened and closed with respect to the grip11.

On the proximal end side of the housing5, an ultrasonic transducer unit8is provided. The ultrasonic transducer unit8has an ultrasonic transducer13including at least one piezoelectric element. The ultrasonic transducer unit8is detachably connected to the energy control device3via a cable9. AC power is supplied from the energy control device3to the ultrasonic transducer13of the ultrasonic transducer unit8, thereby causing the ultrasonic transducer13to vibrate.

A rod member14is connected to the ultrasonic transducer13. The rod member14passes through the inside of the housing5and the shaft6and reaches the end effector7. That is, the distal end portion of the rod member14constitutes a first grasping piece15of the end effector7. The rod member14is formed of a material having a high vibration transmission property such as a titanium alloy. The ultrasonic vibration generated by the ultrasonic transducer13is transmitted to the rod member14. As a result, the first grasping piece15vibrates. The first grasping piece15vibrates at a resonance frequency of the vibration system that is designed arbitrarily. The frequency of this resonance is not limited to this, and may, for example, be approximately several tens of kHz, for example, equal to or greater than 46 kHz and equal to or less than 48 kHz (approximately 47 kHz).

A second grasping piece16is attached to the distal end portion of the shaft6that is opened and closed with respect to the first grasping piece15. The second grasping piece16and the handle12are connected by a movable member17passing inside the shaft6. By opening or closing the handle12with respect to the grip11, the movable member17moves to the distal end side or the proximal end side, and the second grasping piece16rotates with respect to the shaft6to open or close with respect to the first grasping piece15. In this manner, the opening and closing operations of the handle12with respect to the grip11causes the first grasping piece15and the second grasping piece16of the end effector7to open and close. The end effector7is configured to grip the living tissue to be treated by the first grasping piece15and the second grasping piece16constituting a pair of grasping pieces.

The second grasping piece16comprises a pad member21and a holder member22to which the pad member21is attached. The pad member21is formed of a resin such as polytetrafluoroethylene (PTFE). When the first grasping piece15and the second grasping piece16close, the pad member21of the second grasping piece16comes into contact with the first grasping piece15, while the other regions of the second grasping piece16do not come into contact with the first grasping piece15.

FIGS. 2A and 2Bare views showing a cross section perpendicular to the longitudinal axes of the first grasping piece15and the second grasping piece16when using the ultrasonic treatment tool2.FIG. 2Ashows a state in which a tissue O1to be treated is sandwiched between the first grasping piece15and the second grasping piece16. While sandwiching the tissue O1between the first grasping piece15and the second grasping piece16, the ultrasonic treatment tool2can incise the tissue O1and at the same time promote coagulation of the same by the ultrasonic vibration from the first grasping piece15.FIG. 2Bshows a state in which the tissue is incised into a first tissue piece O2and a second tissue piece O3. At this moment, the pad member21is in contact with the first grasping piece15.

As shown inFIG. 1, the housing5is provided with an operating button19. The operating button19is actuated to switch the supply of electric power from the energy control device3to the ultrasonic transducer unit8on or off. The treatment system1may be provided with a foot switch having the same function as the operating button19instead of or together with the operating button19.

FIG. 3is a schematic diagram showing an example of a configuration of the treatment system1pertaining to the supply of electric power from the energy control device3to the ultrasonic treatment tool2.

As described above, the ultrasonic treatment tool2is provided with the ultrasonic transducer13, the first grasping piece15, and the second grasping piece16. The ultrasonic treatment tool2is further provided with a switch20and a storage medium25as shown inFIG. 3, The ultrasonic transducer13is an ultrasonic transducer as a vibration source provided in the ultrasonic transducer unit8described above. The switch20is provided inside the housing5of the ultrasonic treatment tool2. By actuating the operating button19, the switch20is switched on or off. The storage medium25stores information on the treatment tool. The ultrasonic treatment tool2is provided as needed with various sensors28. The sensors28may, for example, be sensors for detecting the amount with which the handle12is being gripped, indicative of the amount of displacement of the handle12. This gripping amount is represented, for example, by the amount of displacement of the handle12from the most open position with respect to the grip11. The sensors28may further be sensors for detecting the amount of force with which the tissue is being grasped, indicative of the force with which the living tissue to be treated is being grasped by the first grasping piece15and by the second grasping piece16.

The energy control device3comprises a control circuit40for controlling the operations of the treatment system1, and a storage medium48. The control circuit40operates based on, for example, a program stored in the storage medium48to control the operations of each part of the energy control device3. Stored in the storage medium48are a processing program used in the control circuit40, parameters and tables used for calculations performed in the control circuit40, and the like.

The energy control device3further comprises a first power supply51. Under the control of the control circuit40, the first power supply51supplies AC power to the ultrasonic transducer13of the ultrasonic treatment tool2, a frequency of the AC power corresponding to ultrasonic frequency. The electric power supplied from the first power supply51causes the ultrasonic transducer13to vibrate at the resonant frequency, whereby the first grasping piece15vibrates at a frequency in the ultrasonic range to treat the living tissue with which the first grasping piece15is in contact.

The energy control device3may further comprise a second power supply52. The second power supply52applies a predetermined voltage between the first grasping piece15and the second grasping piece16under the control of the control circuit40. When the output from the second power supply52is a sufficiently strong high-frequency power output, a high-frequency current flows into the living tissue that is grasped between the first grasping piece15and the second grasping piece16, by which the living tissue can be treated by a Joule heat generated in the living tissue. The second power supply52may be configured to output an energy small enough to measure the impedance between the first grasping piece15and the second grasping piece16.

The energy control device3comprises a first detection circuit53. The first detection circuit53comprises a voltage detection circuit, a current detection circuit, and an A/D converter. The first detection circuit53detects the output voltage and the output current of the first power supply51and transmits the detection result to the control circuit40as a digital signal. The control circuit40controls the output of the first power supply51based on the voltage value and the current value detected by the first detection circuit53, the impedance value calculated therefrom, and the like.

The energy control device3may further comprise a second detection circuit54. The second detection circuit54comprises a voltage detection circuit, a current detection circuit, and an A/D converter. The second detection circuit54detects the output voltage and the output current of the second power supply52and transmits the detection result to the control circuit40as a digital signal. The control circuit40can calculate the impedance value of the living tissue grasped between the first grasping piece15and the second grasping piece16based on the voltage value and the current value detected by the second detection circuit54. The calculated impedance value is used for controlling the outputs of the first power supply51and the second power supply52. The second detection circuit54may detect the output voltage and the output current which is related to the output of the second power supply52that outputs the high frequency power for treating the living tissue grasped by the end effector7. The second detection circuit54may further detect the output voltage and the output current which is related to the output of the second power supply52that outputs a weak power for measuring the impedance of the living tissue grasped by the end effector7.

The energy control device3further comprises an input unit62and a notification unit64. The input unit62is a unit that receives an input by the user to the energy control device3. The input unit62includes, for example, a touch panel, a button switch, a keyboard, or the like. The notification unit64is a unit for announcing information to the user. The notification unit64includes, for example, a display or a speaker.

The energy control device3according to the first embodiment performs the following operations. When the switch20of the ultrasonic treatment tool2is switched on, the energy control device3detects this and starts supplying the electric power to the ultrasonic treatment tool2. Subsequently, the energy control device3measures the duration of treatment, that is, the duration of power supply from the start, and after a predetermined time has elapsed, it determines that the treatment has completed, at which point it puts out a notification that the output has been stopped or reduced, that the treatment has been completed or the like. The control circuit40performs calculations related to these operations of the energy control device3.

The control circuit40comprises a clock unit41, a monitoring unit42, a threshold value setting unit43, and an output control unit44. The clock unit41measures the output duration related to the time during which the first power supply51continues to output. In the first embodiment, the duration of output from the time that the first power supply51began outputting is measured as the output duration.

The monitoring unit42monitors a predetermined characteristic parameter. Such a characteristic parameter may be the current supplied from the first power supply51to the ultrasonic transducer13(referred to as ultrasonic current), correlating with the vibration amplitude of the ultrasonic transducer13, namely the amplitude of the first grasping piece15. Such a characteristic parameter may further be the amount with which the handle12is being gripped, obtained by the sensors28of the ultrasonic treatment tool2. Such a characteristic parameter may even further be the amount of force with which the living tissue is being grasped by the first grasping piece15and by the second grasping piece16, obtained by the sensors28of the ultrasonic treatment tool2. Such a characteristic parameter may yet even further be the initial value or the like, of, for example, the impedance value between the first grasping piece15and the second grasping piece16calculated from the current value and the voltage value detected by the second detection circuit54, that is, the impedance value related to the living tissue.

The threshold value setting unit43sets a time threshold value being a threshold value related to the time measured by the clock unit41based on the characteristic parameter. The output control unit44controls the outputs of the first power supply51and the second power supply52. In particular, when the output duration measured by the clock unit41exceeds the time threshold value set by the threshold value setting unit43, the output control unit44stops the output of power to the ultrasonic transducer13from the first power supply51. The output control unit44may, instead of stopping the output, reduce the output or notify, by using the notification unit64, the user of the circumstance that the output duration has exceeded the time threshold value.

The control circuit40includes an integrated circuit such as a central processing unit (CPU), an application specific integrated circuit (ASIC), or a field programmable gate array (FPGA). The control circuit40may be constituted by a single integrated circuit or the like, or a combination of a plurality of integrated circuits or the like. The operations of these integrated circuits are performed by a program recorded in, for example, the storage medium48or in a recording area in the integrated circuit.

Treatment System Operations

The operations of the treatment system1according to the first embodiment will be described. When treating the treatment target such as living tissue by using the treatment system1, the user holds the grip11and the handle12, and inserts the end effector7into a body cavity such as an abdominal cavity or the like. The user places the treatment target such as living tissue between the first grasping piece15and the second grasping piece16, and closes the handle12with respect to the grip11. As a result, the second grasping piece16is closed with respect to the first grasping piece15, and the living tissue is grasped between the first grasping piece15and the second grasping piece16.

In this state, the user switches on the operating button19. At this point, the control circuit40detects that the switch20has been switched on. The output control unit44of the control circuit40causes the first power supply51to start outputting power. The first power supply51supplies the power to the ultrasonic transducer13under the control of the control circuit40. As a result, the ultrasonic transducer13generates ultrasonic vibration and the generated ultrasonic vibration is transmitted to the first grasping piece15via the rod member14. When the first grasping piece15starts ultrasonically vibrating while the tissue to be treated is being grasped between the first grasping piece15and the second grasping piece16, frictional heat is being generated between the first grasping piece15and the tissue being grasped. The frictional heat denatures the protein in the living tissue, thereby both promoting coagulation of the living tissue and incising the living tissue.

The control circuit40may further cause the second power supply52to output power together with the first power supply51, when the energy control device3has the second power supply52that outputs the high-frequency power. In that case, under the control of the control circuit40, the second power supply52applies a high-frequency voltage between the first grasping piece15and the second grasping piece16. As a result, a high-frequency current flows through the living tissue grasped between the first grasping piece15and the second grasping piece16. By this high frequency current, a Joule heat is generated in the living tissue. This heat also promotes coagulation of the living tissue.

When the tissue to be treated has been incised, the first grasping piece15and the second grasping piece16are in contact, as shown inFIG. 2B. In this state, the pad member21of the second grasping piece16or the like may suffer damage when the first grasping piece15continues vibrating ultrasonically. Therefore, in the first embodiment, the control circuit40estimates the point in time at which the tissue will be incised. Based on the time during which the treatment is being performed, that is, based on the elapsed time since the first power supply51began outputting power, the control circuit40causes to stop the supply of electric power to the ultrasonic transducer13or to be decreased, or it notifies the user that the tissue has presumably been incised.

Output Control Process

The output control performed by the control circuit40will be described with reference to the flowchart shown inFIG. 4. The output control process shown inFIG. 4starts when, for example, the user pushes the operating button19.

In step S101, the control circuit40initializes the various parameters. For example, the parameter T representing the elapsed time of the treatment is set to 0, and the second time threshold value Tth2indicative of the timing at which to reduce the output is set to Tave, namely the standard value.

In step S102, the output control unit44of the control circuit40causes the first power supply51to start outputting power. Under the control of the control circuit40, the first power supply51supplies a predetermined power to the ultrasonic transducer13. As a result, the first grasping piece15vibrates at a frequency in the ultrasonic range to perform the living tissue treatment. In step S103, the clock unit41of the control circuit40starts measuring the elapsed time T of the treatment. That is, the clock unit41starts counting the parameter T. Using the elapsed time T, the continued duration of power output by the first power supply51since the output began is measured.

Generally, when performing a treatment, the temperature of the first grasping piece15increases gradually and the state of the living tissue contacting the first grasping piece15also changes, so that the resonant frequency of the first grasping piece15changes. The control circuit40thus causes the first power supply51to scan the output frequency, and then start controlling for which the phase-locked loop (PLL) is used for causing the first power supply51to output electric power. That is, the output control unit44of the control circuit40causes the first power supply51to output power while gradually changing the output frequency, for example, from high frequency to low frequency in the vicinity of the resonant frequency of the vibration system including the ultrasonic transducer13. The control circuit40obtains the current and voltage at that point from the first detection circuit53and obtains the frequency at which the phases of the current and the voltage coincide, that is, the resonant frequency of the vibration system. The control circuit40renders the obtained resonant frequency the initial value and uses the PLL even subsequent to that so as to cause the output frequency to follow the resonant frequency of the vibration system. Subsequently, the first grasping piece15is caused to vibrate at the resonant frequency using the PLL. Generally, since the temperature of the first grasping piece15gradually increases, the resonant frequency of the vibration system gradually decreases.

In step S104, the control circuit40determines whether or not the elapsed time T exceeds a predetermined first time threshold value Tth1. If the elapsed time T is not greater than the predetermined first time threshold value Tth1, the process in step S104is repeated. That is, the process is in stand-by until the elapsed time T exceeds the first time threshold value Tth1. When the elapsed time T exceeds the first time threshold value Tth1, the process continues to step S105.

In step S105, the monitoring unit42of the control circuit40obtains a characteristic parameter X. Although the characteristic parameter X will be described later, it is, for example, the ultrasonic vibration amplitude of the ultrasonic transducer13represented by the output current to the ultrasonic transducer13or of the first grasping piece15, the amount with which the handle12is being gripped, the amount of force with which the living tissue is being grasped by the end effector7, the electrical impedance initial value of the living tissue being grasped by the end effector7etc.

The timing of obtaining the characteristic parameter X defined by the first time threshold value Tth1may be any timing. For example, it may be after starting the PLL control. It may also be immediately after turning on the output switch.

In step S106, if it is determined that the characteristic parameter X is equal to or greater than the predetermined second threshold value x2and equal to or less than the predetermined first threshold value x1(that is greater than the second threshold value x2), the process continues to step S108. In step S108, the threshold value setting unit43of the control circuit40sets the second time threshold value Tth2to Tave, namely to the standard value set at the time of initialization. Subsequently, the process continues to step S110.

In step S106, if it is determined that the characteristic parameter X is greater than the predetermined first threshold value x1, the process continues to step S109. In step S109, the threshold value setting unit43of the control circuit40sets the value of the second time threshold value Tth2to the value Tdown that is less than the standard value Tave. Subsequently, the process continues to step S110.

In step S110, the control circuit40determines whether the elapsed time T exceeds the second time threshold value Tth2set in step S107, step S108or step S109. If the elapsed time T is not greater than the second time threshold value Tth2, step S110of the process is repeated. That is, until the elapsed time T exceeds the second time threshold value Tth2, the treatment is continued. If the elapsed time T exceeds the second time threshold value Tth2, the process continues to step S111.

In step S111, the output control unit44of the control circuit40performs output reduction. The output reduction operations are, for example, stopping the output of power from the first power supply51or lowering the output of power from the first power supply51. The output reduction operations may be notifying the user, by the notification unit64, that the elapsed time T has reached the second time threshold value Tth2. This operation may be, for example, outputting a display to a screen, outputting a notifying sound from a speaker, and the like. The output reduction operations may yet further be a combination of stopping or lowering the output power and notifying. After the process in step S111, the output control process ends.

The characteristic parameter X may be the amplitude of the ultrasonic vibration of the ultrasonic transducer13or the first grasping piece15. Since this amplitude correlates with the current value supplied to the ultrasonic transducer13, the characteristic parameter X may be the current value supplied to the ultrasonic transducer13. As the amplitude of the ultrasonic vibration increases, the treatment of the living tissue grasped by the end effector7progresses more quickly. Therefore, the greater the amplitude of the ultrasonic vibration is, the shorter the second time threshold value Tth2(namely the threshold value of the output duration) is set, and the less the amplitude of the ultrasonic vibration is, the longer it is set.

The characteristic parameter X may further be the amount with which the handle12is being gripped, obtained by the sensors28of the ultrasonic treatment tool2. The greater the amount with which the handle12is being gripped, the stronger the living tissue is grasped by the first grasping piece15and the second grasping piece16of the end effector7. The greater the end effector7grasps, the faster the treatment proceeds. Therefore, the greater the amount with which the handle12is being gripped is, the shorter the second time threshold value Tth2(namely the output duration threshold value) is set, and the less the amount with which the handle12is being gripped, the longer it is set.

The force with which the living tissue is being grasped by the end effector7is not limited to being obtained by the amount with which the handle12is being gripped, but may be directly obtained by the sensors28of the ultrasonic treatment tool2. That is, the characteristic parameter X may be the amount with which the living tissue is being grasped by the first grasping piece15and the second grasping piece16of the end effector7, obtained by the sensors28of the ultrasonic treatment tool2. The greater the amount of grasping force is, the shorter the second time threshold value Tth2(namely the output duration of the threshold value) is set, and the less the amount of grasping force is, the longer it is set.

The characteristic parameter X may even further be the impedance value between the first grasping piece15and the second grasping piece16calculated from the current value and the voltage value detected by the second detection circuit54, that is, it may be the impedance value of the living tissue being grasped by the end effector7. This impedance value may, for example, be the initial value or various values representing the characteristics of the impedance value when it is varying. As the moisture content of the living tissue increases, the impedance value decreases. The greater the moisture content of the living tissue, the longer the treatment takes. Therefore, the lower the impedance value is, the longer the second time threshold value Tth2(namely the threshold value of the output duration) is set, and the higher the impedance value is, the shorter it is set.

The second time threshold value Tth2may be set to respective predetermined values according to the value of the characteristic parameter X being either: less than the predetermined second threshold value x2, equal to or greater than the second threshold value x2and equal to or less than the first threshold value x1, or greater than the first threshold value x1. The second time threshold value Tth2may further be set based on the relationship between the second time threshold value Tth2and the characteristic parameter X determined in advance according to the value of the characteristic parameter X being either: less than the predetermined second threshold value x2, equal to or greater than the second threshold value x2and equal to or less than the first threshold value x1, or greater than the first threshold value x1. That is, for example, even if the value of the characteristic parameter X is less than the predetermined second threshold value x2, the second time threshold value Tth2may be configured to differ according to the value of the characteristic parameter X. Besides, although the above example scenario has been classified into three different scenarios depending on the value of the characteristic parameter X, the present example scenario may be classified into four or more.

As for any of the above-mentioned cases of the characteristic parameter X, there is a tendency to set the second time threshold value Tth2to a lesser value the greater the value of the characteristic parameter X is, and to set the second time threshold value Tth2to a greater value the less the characteristic parameter X is.

It should be noted that the characteristic parameter X is not limited to the above example, but that it may be any parameter as long as it represents a treatment situation of the ultrasonic treatment tool2and as long as it affects the treatment time. The second time threshold value Tth2is appropriately set depending on whether the treatment time increases or decreases with the parameter.

In the treatment system1according to the first embodiment, when the treatment of the living tissue to be treated is completed and the tissue is incised or nearly incised, the ultrasonic vibration of the first grasping piece15is stopped or reduced, or a notice etc. to that effect is made. In this way, ultrasonic vibration of the first grasping piece15while the first grasping piece15and the pad member21of the second grasping piece16are in contact with each other is prevented. As a result, a lid is kept on abrasion and deformation of the pad member21.

The determination, here, as to whether or not to stop the ultrasonic vibration of the first grasping piece15or the like is made based on the elapsed time from the start of the treatment. The threshold for determining the elapsed time, here, is set based on the characteristic parameter which reflects the situation of the treatment. The situation of the treatment varies depending on the type or characteristics of the targeted tissue, on how the user uses the ultrasonic treatment tool2, and the like. Since the threshold value for the determination is set according to the situation of the treatment, the treatment system1according to the first embodiment can appropriately control the output according to the treatment situation.

Second Embodiment

A second embodiment and its differences from the first embodiment will be described. In this regard, same elements will be denoted by the same reference symbols and descriptions of same elements will be omitted. In the first embodiment, the characteristic parameter X is obtained once at a predetermined timing, and, based thereon, the second time threshold value Tth2is set only once. In contrast to this, in the second embodiment, the value of the characteristic parameter X is obtained repeatedly, and, based thereon, the second time threshold value Tth2is set sequentially. The other operations are the same as in the first embodiment.

The output control process according to the second embodiment will be described with reference to the flowchart shown inFIG. 6. The process related to steps S201to S210is similar to the process related to steps S101to S110of the output control process according to the first embodiment described with reference toFIG. 4. The following is a brief explanation.

In step S201, the control circuit40initializes the various parameters. In step S202, the output control unit44of the control circuit40causes the first power supply51to start outputting. In step S203, the clock unit41of the control circuit40starts measuring the elapsed time T of the treatment. In step S204, the control circuit40determines whether or not the elapsed time T exceeds the predetermined first time threshold value Tth1. If the elapsed time T exceeds the first time threshold value Tth1, the process continues to step S205.

In step S205, the control circuit40obtains the characteristic parameter X. In step S206, the control circuit40evaluates the characteristic parameter X. If the characteristic parameter X is less than the predetermined second threshold value x2, the control circuit40sets, in step S207, the value of the second time threshold value Tth2to the value Tup greater than the standard value Tave. If it is determined that the characteristic parameter X is equal to or greater than the predetermined second threshold value x2and equal to or less than the predetermined first threshold value x1that is greater than the second threshold value x2, the control circuit40sets, in step S208, the second time threshold value Tth2to the standard value Tave set at the time of initialization. If the characteristic parameter X is greater than the predetermined first threshold value x1, the control circuit40sets, in step S209, the value of the second time threshold value Tth2to the value Tdown that is less than the standard value Tave set at the time of initialization.

In step S210, the control circuit40determines whether or not the elapsed time T exceeds the set second time threshold value Tth2. If the elapsed time T does not exceed the second time threshold value Tth2, the process continues to step S211. In step S211, the control circuit40waits for a predetermined interval period ΔT to adjust the timing. That is, the elapsed time T is T+ΔT. Therefore, ΔT may, for example, be approximately 10 microseconds to 10 seconds.

Subsequent to the process of step S211, the process returns to step S205. In this manner, the process from step S205to step S211is repeated until the elapsed time T exceeds the second time threshold value Tth2. That is, the control circuit40obtains the characteristic parameter X repeatedly, and resets the second time threshold value Tth2based thereon.

If the elapsed time T exceeds the second time threshold value Tth2, the control circuit40performs the output reduction operations in step S212. Subsequently, the output control process ends.

In the second embodiment, the same effects as in the first embodiment are achievable. According to the second embodiment, the second time threshold value Tth2for adjusting the timing of stopping the output of the ultrasonic treatment tool2and the like is adjusted, according to the characteristic parameter X changing constantly during the treatment. As a result, it is possible to perform an output reduction operations by which the output is stopped at the optimal timing and the like.

Third Embodiment

A third embodiment and its differences from the first embodiment will be described. In this regard, same elements will be denoted by the same reference symbols and descriptions of same elements will be omitted. In the first embodiment, the value of the characteristic parameter X is compared to a predetermined threshold value, and, according to the magnitude, the second time threshold value Tth2is determined. In contrast to this, in the third embodiment, the second time threshold value Tth2is determined as a function of the characteristic parameter X. The other operations are the same as in the first embodiment.

The output control process according to the third embodiment will be described with reference to the flowchart shown inFIG. 7. The process related to steps S301to S305is the same as the process related to steps S101to S105of the output control process according to the first embodiment described with reference toFIG. 4. The following is a brief explanation.

In step S301, the control circuit40initializes the various parameters. In step S302, the output control unit44of the control circuit40causes the first power supply51to begin outputting. In step S303, the clock unit41of the control circuit40begins measuring the elapsed time T of the treatment. In step S304, the control circuit40determines whether or not the elapsed time T exceeds the predetermined first time threshold value Tth1. If the elapsed time T exceeds the first time threshold value Tth1, the process continues to step S305. In step S305, the control circuit40obtains the characteristic parameter X.

In step S306, the control circuit40determines the second time threshold value Tth2based on the function Tth2=T(X) indicating the second time threshold value Tth2with respect to the characteristic parameter X and the obtained characteristic parameter X.

An example of the relationships between examples for the characteristic parameter X and the function T(X) is shown inFIG. 8. As in the case of the first embodiment, the characteristic parameter X is obtained by calculating the ultrasonic vibration amplitude (current value supplied to the ultrasonic transducer13), the amount with which the handle12is being gripped, the amount of force with which the living tissue is being grasped by the end effector7, the impedance value of the living tissue, and the like. Whichever of the above examples the characteristic parameter X is, the function T(X) is negative. The function T(X) may be of the n-th order, exponential, logarithmic, or any other.

In step S307, the control circuit40determines whether or not the elapsed time T exceeds the set second time threshold value Tth2. If the elapsed time T does not exceed the second time threshold value Tth2, the control circuit40continues the treatment. If the elapsed time T exceeds the second time threshold value Tth2, the control circuit40performs the output reduction operations in step S308. Subsequently, the output control process ends.

In the third embodiment, the same effects as in the first embodiment are achievable. According to the third embodiment, the second time threshold value Tth2is appropriately adjusted based on the function T(X) and the characteristic parameter X. As a result, it is possible to perform an output reduction operations by which the output is stopped at the optimal timing and the like.

Fourth Embodiment

A fourth embodiment and its differences from the third embodiment will be described. In this regard, same elements will be denoted by the same reference symbols and descriptions of same elements will be omitted. In the third embodiment, the characteristic parameter X is obtained once at a predetermined timing, and, based thereon, the second time threshold value Tth2is set only once. In contrast to this, in the fourth embodiment, as in the second embodiment, the value of the characteristic parameter X is obtained repeatedly, and, based thereon, the second time threshold value Tth2is set sequentially. The other operations are the same as in the third embodiment.

The output control process according to the fourth embodiment will be described with reference to the flowchart shown inFIG. 9. The process related to steps S401to S407is the same as the process related to steps S301to3307of the output control process according to the third embodiment described with reference toFIG. 7. The following is a brief explanation.

In step S401, the control circuit40initializes the various parameters. In step S402, the output control unit44of the control circuit40causes the first power supply51to begin outputting. In step S403, the clock unit41of the control circuit40begins measuring the elapsed time T of the treatment. In step S404, the control circuit40determines whether or not the elapsed time T exceeds the predetermined first time threshold value Tth1. If the elapsed time T exceeds the first time threshold value Tth1, the process continues to step S405. In step S405, the control circuit40obtains the characteristic parameter X. In step S406, the control circuit40determines the second time threshold value Tth2based on the function Tth2=T(X) indicating the second time threshold value Tth2with respect to the characteristic parameter X and the obtained characteristic parameter X.

In step S407, the control circuit40determines whether or not the elapsed time T exceeds the set second time threshold value Tth2. If the elapsed time T does not exceed the second time threshold value Tth2, the process continues to step S408. In step S408, the control circuit40waits for the predetermined interval period ΔT to adjust the timing. That is, the elapsed time T is T+ΔT. Subsequently, the process returns to step S405. In this manner, the control circuit40obtains the characteristic parameter X repeatedly, and, based thereon, resets the second time threshold value Tth2.

If the elapsed time T exceeds the second time threshold value Tth2, the control circuit40performs the output reduction operations in S409. Subsequently, the output control process ends.

In the fourth embodiment, the same effects as in the third embodiment are achievable. According to the fourth embodiment, the second time threshold value Tth2for adjusting the timing of stopping the output of the ultrasonic treatment tool2or the like is adjusted according to the characteristic parameter X varying constantly during the treatment. As a result, it is possible to perform an output reduction operations by which the output is stopped at the optimal timing and the like.

Modifications

Several modifications of the above first to fourth embodiments will be described. These modifications may be applied in combination with each other as long as they do not contradict.

In the above embodiments, examples in which the output reduction operations have been performed according to the elapsed time T from the start of output of the ultrasonic treatment tool2have been described. However, the elapsed time T may not be measured from the start of output. The elapsed time T may, for example, be measured from the start of the above PLL control. The elapsed time T may also be measured from the time at which the obtained electrical impedance of the ultrasonic transducer13indicates the minimum value or the maximum value. That is, the output duration related to the time during which the first power supply51continued outputting may be measured as the elapsed time T.

The relationship between the characteristic parameter X and the second time threshold value Tth2may be different for each model of the ultrasonic treatment tool2. Therefore, the relationships between the characteristic parameter X and the second time threshold value Tth2may be determined as follows. That is, in the storage medium25of the ultrasonic treatment tool2, for example, identification information indicating the model of the ultrasonic treatment tool2is stored. Further, in the storage medium48of the energy control device3, the relationships between the characteristic parameters X and the second time threshold values Tth2for the models are stored. The control circuit40reads the model identification information from the storage medium25of the ultrasonic treatment tool2and uses the relationship between the characteristic parameter X and the second time threshold value Tth2corresponding to the identification information.

It should be noted that, even if the model information of the ultrasonic treatment tool2is not stored in the storage medium25, different resistors may, for example, be provided in the ultrasonic treatment tool2depending on the model of the ultrasonic treatment tool2, and the energy control device3may discriminate the model of the ultrasonic treatment tool.2by obtaining the resistance value of the resistor at the time of connecting to the ultrasonic treatment tool2. The relationship between the characteristic parameter X and the second time threshold value Tth2may further be stored in the storage medium25of the ultrasonic treatment tool2, and the control circuit40may read this information to set the second time threshold value Tth2.

Moreover, the energy control device3may be configured such that the type of output reduction operations according to the above embodiment or the presence or absence thereof can be switched based on instructions by the user input via the input unit62.

Moreover, in the above embodiments, the case has been shown in which only a single second time threshold value Tth2is set. However, two or more second time threshold values Tth2may be set. For example, the energy control device3may be configured to reduce the output if the elapsed time T exceeds the first second time threshold value Tth21, and to stop the output if the elapsed time T exceeds the second time threshold value Tth22.

Further, in the above embodiments, a single parameter has been obtained as the characteristic parameter X, and, based thereon, the second time threshold value Tth2has been determined. However, the present invention is not limited to this. A plurality of parameters may be obtained as the characteristic parameter X, and the second time threshold value Tth2may be determined by a combination of these parameters.

It should be noted that in the above embodiments, the ultrasonic treatment tool2has been described as a tool performing treatment by the first grasping piece15that ultrasonically vibrate. However, the present invention is not limited to this. In the case where the energy control device3has the second power supply52, the ultrasonic treatment tool2may also serve as a high-frequency treatment tool applying, in addition to the ultrasonic vibration, a high-frequency voltage between the first grasping piece15and the second grasping piece16. The high-frequency treatment tool performs treatment with a Joule heat generated by current flowing through the tissue to be treated by applying a high-frequency current to the tissue. The ultrasonic treatment tool.2may further be a treatment tool provided with a heater on the first grasping piece15or the second grasping piece16for treating the tissue to be treated by both the heat from the heater and the ultrasonic vibration.