Patent Application
20070016235
The present application relates to and incorporates by reference Japanese Patent application No. 2004-351801 filed on Dec. 3, 2004.
1. Field of the Invention
The present invention relates to an ultrasonic surgical apparatus and a method for driving an ultrasonic treatment device, and in particular, to an ultrasonic surgical apparatus for effecting treatment by holding living tissue which is subjected to surgery, and a method for driving an ultrasonic treatment device.
2. Description of Related Art
Ultrasonic surgical apparatuses have been in practical use, by which living tissue is incised by allowing a treatment device to vibrate with ultrasonic mechanical vibration.
An example of such an ultrasonic surgical apparatus is disclosed in Japanese Unexamined Application Publication No. H09-299381. This ultrasonic surgical apparatus has an ultrasonic treatment device which is provided with a gripper and a probe in order to grip a living tissue portion to be treated. An ultrasonic transducer is coupled to the probe to transfer longitudinal vibration of the transducer to the probe. The probe mechanically vibrates when a predetermined electrical signal is supplied to the ultrasonic transducer. When living tissue is gripped between the gripper opened/closed by a drive power and the probe to which ultrasonic vibration is transferred, the living tissue portion can be incised by the frictional heat generated between the vibrating probe and the living tissue portion.
However, the magnitude (amplitude) of ultrasonic vibration generated in a probe is determined by the amplitude of current supplied to an ultrasonic transducer. An electrical signal supplied to an ultrasonic transducer has an ultrasonic frequency which is outputted while a foot switch is being turned on by an operator.
For this reason, an electrical signal has been supplied to an ultrasonic transducer to allow a probe to have constant amplitude while the foot switch is turned on. Therefore, the temperature of a treatment device has often exceeded a desired value.
The present invention has been made in view of the problem described above, and provides an ultrasonic surgical apparatus with improved performance for the control of the heat generation in a treatment device thereof.
One aspect of the present invention is to provide an ultrasonic surgical apparatus comprising an ultrasonic transducer for generating vibration in response to the input of a drive signal, a treatment device having a probe to which the vibration is transferred from the ultrasonic transducer, a signal generator for generating an AC (alternating current) signal for driving the ultrasonic transducer, and a modulator for modulating the AC signal generated by the signal generator to produce the drive signal and for giving the drive signal to the ultrasonic transducer.
Another aspect of the present invention is to provide a method of driving an ultrasonic treatment device provided with an ultrasonic transducer, the method comprising steps of producing an AC (alternating current) signal for driving the ultrasonic transducer, modulating amplitude of the AC signal, so that a duty ratio “T1/(T1+T2)” is 5% to 100% and a period “T1+T2” is 0.1 seconds to 1 seconds (T1=high output period, T2=low output period) to produce a drive signal, and supplying the drive signal to the ultrasonic transducer.
In the appended drawings:
Hereinafter, various embodiments of the ultrasonic surgical apparatus according to the present invention will now be described with reference to the accompanying drawings.
With reference to
The main unit 1 drives the handpiece 2. The handpiece 2 is provided with an elongated sheath 4, with a treatment device 5 being provided at a tip thereof and an operating portion 6 being provided at a base (portion placed in an operator's hand) thereof. A case 7 for accommodating an ultrasonic transducer 2a (see
Inside the sheath 4, an ultrasonic probe 9 is disposed to transfer the ultrasonic vibration generated by the ultrasonic transducer 2a to the treatment device 5. A tip of this probe 9 is exposed from a tip of the sheath 4. Further, a gripper 10 which is opened/closed by a driving power with respect to the tip of the probe 9 is provided at the treatment device 5. The gripper 10 is coupled to a tip of the sheath 4 so as to enable pivotal movement thereof about a pivot pin. As is well known, an arrangement is so made that, by operating the operation handle 8, the gripper 10 is driven to open/close with respect to the tip of the probe 9, so that a living tissue portion can be gripped between the probe 9 and the gripper 10.
As shown in
Among them, the handpiece connecting portion 14 is detachably connected with a connector cable 15 which is connected to the handpiece 2. Specifically, one end of the connector cable 15 is connected to the operating portion 6 of the handpiece 2, and a connector 16 disposed at the other end of the connector cable 15 is detachably connected to the handpiece connecting portion 14.
The operation display panel 13 of the main unit 1 is provided with: a setting switch 17 (which functions as ultrasonic output setting means) for setting or changing the magnitude of ultrasonic output (i.e., vibration energy of the ultrasonic transducer 2a), that is, an amplitude value, in effecting ultrasonic treatment; and a display 18 for digitally displaying the magnitude of ultrasonic output set at the setting switch 17. Among them, the setting switch 17 includes an output increase switch 17a and an output decrease switch 17b for increasing and decreasing, i.e. for changing, the magnitude of ultrasonic output.
It should be understood that, in the present embodiment, the magnitude of ultrasonic output is described as being its ratio to 100% output, and setting or changing of the magnitude of ultrasonic output is described as setting or changing its ratio to 100% output.
As described above, the foot switch 3 is connected to the main unit 1. The foot switch 3 has pedal member 3a. Thus, in response to the stepping operation of an operator onto the pedal member 3a, a control signal is outputted to the main unit 1 from the foot switch 3 to effect on/off control of an output of the ultrasonic vibration from the ultrasonic transducer.
The aforementioned ultrasonic transducer 2a and a resistor 2b for determining a type (shape, size, material, etc.) of the handpiece 2 functioning as a treatment device, are provided inside the handpiece 2.
Among them, the ends of the resistor 2b are electrically connected to the main unit 1 through wires and the connector cable 15. The main unit 1, as shown in
The HP determination circuit 21 and the CPU 22 constitute a principal part of determination means for determining the type of a handpiece. The function of determining a handpiece type is realized by this determination means.
In addition to the function of determining a handpiece type as described above, the main unit 1 has a resonance frequency detecting function, a PLL (phase-locked loop) function and a constant current supplying function.
In order to achieve these functions, the main unit 1 is provided with the following electric circuit components, in addition to the aforementioned HP determination circuit 21 and the CPU 22. Particularly, the main unit 1 further comprises a ROM 22a connected to the CPU 22, resonance frequency detection circuit 23, sweep circuit 24, up/down counter (hereinafter referred to as a U/D counter) 25, direct digital synthesizer (hereinafter abbreviated to DDS) 26, phase comparator 27, digital/analogue converter (hereinafter referred to as a D/A converter) 28, comparator 29, multiplier 30 serving as a modulation member, power amplifier 31, detection circuit 32 and analogue/digital converter (hereinafter referred to as an A/D converter) 33.
Among them, the ROM 22a is a memory for storing waveform pattern data of a drive current supplied to the transducer 2a. It should be understood that a RAM, not shown, is connected to the CPU 22, and that programs for performing various controls are stored in the ROM 22, so that the CPU 22 can perform the programs that have been read out from the ROM 22a using the RAM.
Such circuits as the resonance frequency detection circuit 23, the sweep circuit 24, the phase comparator 27, the D/A converter 28 and the A/D converter 33 are electrically connected to the CPU 22.
Further, the resonance frequency detection circuit 23 is electrically connected not only to the CPU 22, but also to the sweep circuit 24, the U/D counter 25 and the phase comparator 27. A phase signal from the detection circuit 32 mentioned above is supplied to the phase comparator 27 and the resonance frequency detection circuit 23.
A function of resonance frequency detection is described first. The function of resonance frequency detection is performed immediately after commencement of, i.e. at the time of starting, output to the handpiece 2. Particularly, when the pedal member 3a is stepped on, the function of resonance frequency detection is performed.
The CPU 22 permits the resonance frequency detection circuit 23 to operate at this starting time to detect resonance frequency. In particular, at the time of starting, the CPU 22 outputs to the sweep circuit 24 a sweep starting signal SWP and a starting frequency signal SF for indicating a starting frequency FO for starting sweeping. The sweep circuit 24 sets at the U/D counter 25 a count value corresponding to the frequency FO, and varies a counter output value of the U/D counter 25 by supplying an up signal or a down signal to the U/D counter 25 for gradually increasing or decreasing the frequency from the set count value. An output of the count value at the U/D counter 25 is supplied to the DDS 26, and a drive current from the DDS 26 is supplied to the transducer 2a as a drive signal. It should be understood that, when performing the function of resonance frequency detection, the CPU 22 outputs a control signal to the phase comparator 27 to stop signal supply to the U/D counter 25.
While the frequency of a drive current supplied to the transducer 2a is varied, the resonance frequency detection circuit 23 detects resonance frequency. Upon detection of resonance frequency, the resonance frequency detection circuit 23 outputs a PLL-on signal to the U/D counter 25 and the phase comparator 27 to turn on a PLL function. The PLL-on signal is also outputted to the sweep circuit 24 which then stops sweeping operation according to the on signal.
As described above, a principal part of resonance frequency detecting means is constituted by the CPU 22, the resonance frequency detection circuit 23, the sweep circuit 24 and the detection circuit 32 to thereby realize a resonance frequency detection function.
When resonance frequency is determined, PLL function is performed.
After the power switch 12 of the main unit 1 has been turned on, PLL function is performed to maintain the level of the resonance frequency as detected.
The detection circuit 32 detects waveforms of a drive current itself supplied to the transducer 2a and of a voltage corresponding thereto. The detection circuit 32 has a rectangular wave shaping circuit, and based on a current value and a voltage value of the drive current, outputs a rectangular wave signals ΔI and ΔV indicative of the respective waveform phases to the phase comparator 27. The phase comparator 27 then detects a phase shift between the rectangular wave signals ΔI and ΔV, and outputs an up signal or down signal according to the shifting amount, to the U/D counter 25. Accordingly, the U/D counter 25 varies the counter value supplied to the DDS 26, i.e. an oscillating circuit, so that the frequency (current frequency) of a drive current matches the detected resonance frequency.
In this way, the PLL function locks the frequency of a drive current supplied to the transducer 2a at a resonance frequency detected by the resonance frequency detection circuit 23, and controls the frequency so as to match the resonance frequency.
As described above, the CPU 22, the U/D counter 25, the DDS 26, the phase comparator 27 and the detection circuit 32 constitute a principal part of PLL means to achieve the PLL function.
Thus, the CPU 22 sets a predetermined value at the U/D counter 25 based on a resonance frequency detected by the resonance frequency detection function and locked by the PLL function. The DDS 26, i.e. an oscillating circuit, then outputs a predetermined frequency based on the set value. Specifically, the DDS 26 outputs an AC (alternating current) signal having a waveform according to a count value from the U/D counter 25, e.g., an AC signal having a sine waveform whose maximum amplitude is 5V (frequency is 27 kHz, for example). The multiplier 30 then multiplies this signal with an amplitude modulating signal imparted to the multiplier 30 to modulate the amplitude. This amplitude-modulated AC signal is then amplified in power by the power amplifier 31 to turn into the aforementioned drive signal (drive current), which is then supplied to the transducer 2a through the detection circuit 32.
At this time, the detection circuit 32 detects a current waveform of the drive current itself as a drive signal to be supplied to the transducer 2a, and also detects a voltage waveform of the drive signal in terms of voltage, as well as an absolute value of the current.
In other words, the detection circuit 32 monitors the drive signal as a drive current and supplies a signal corresponding to an absolute value of the drive current to the A/D converter 33 and the comparator 29. The A/D converter 33 then supplies the absolute value data of the detected drive current to the CPU 22. A drive signal value set at the setting switch 17 of the front panel 11 by an operator has been outputted to the D/A converter 28 by the CPU 22, and the D/A converter 28 supplies an analogue signal of the set value to the comparator 29. The comparator 29, i.e. a differential amplifier, supplies a signal to the multiplier 30 in accordance with the difference between the supplied set value and the detected absolute value of the drive current (amplitude modulating signal). Thus, amplitude modification as described above is performed in the multiplier 30.
In this regard, a signal fed from the CPU 22 through the D/A converter 28 serves as a reference value. This reference value can be controlled by various waveform patterns as will be described later. These waveform patterns are set so that amplitude of a drive signal to be supplied to the transducer 2a can be changed by an adequate mode relative to a time base. In other words, instead of a drive signal that has conventionally had a temporally invariable amplitude, production of a drive signal having a temporally variable amplitude has been enabled.
It should be understood that the DDS 26, the multiplier 30, and the power amplifier 31 constitute drive signal output means.
Constant current supplying function is described hereunder. The circuit configuration of a principal part related to the amplitude modulation described above also serves as a circuit configuration for realizing this constant current supplying function. Specifically, when a living tissue portion is gripped (held) between the probe 9 of the handpiece 2 and the gripper 10, impedance of the transducer goes up, and thus in turn a current goes down, which unavoidably disables desired treatment. In order to prevent this, an arrangement is made such that the comparator 29 supplies a signal to the multiplier 30 according to a difference between a supplied set value and a detected absolute value of a drive current, and that the multiplier 30 multiplies the signal with a signal from the DDS 26 to maintain the amplitude of the drive current at a set value.
Thus, constant current supplying means is constituted of the detection circuit 32, the A/D converter 33, the CPU 22, the D/A converter 28, the comparator 29 and the multiplier 30 to realize the constant current supplying function.
With the use of the ultrasonic surgical apparatus configured as described above, treatment, such as incision, can be effected to living tissue. Further, according to the type of the handpiece 2, frequency and amplitude of a drive current (i.e., drive signal) to be supplied to the handpiece 2, i.e. the transducer 2a, are differentiated. Accordingly, in the ultrasonic surgical apparatus, when the connector cable 15 of the handpiece 2 is connected to the main unit 1, the CPU 22 disposed in the main unit 1 reads a resistance value of the resistor 2b incorporated in the handpiece 2 and determines the type of the handpiece 2 based on the read resistance value. Furthermore, the CPU 22 can adequately effect incision treatment according to the type of the handpiece 2, and can supply an amplitude-controlled drive current to a transducer so that the heat at the time of treatment is not raised excessively high. In other words, the degree of generation of frictional heat at a portion of a subject being held, can be controlled by the ultrasonic vibration of the transducer 2a.
Hereinafter is described an example of a waveform of a drive current as a drive signal which is supplied to the transducer 2a of the handpiece 2 in an ultrasonic surgical apparatus.
If a conventional method is applied, an ultrasonic surgical apparatus is operated such that, when an operator steps on a pedal of the foot switch 3, for example, supply of a drive current to the handpiece 2 is started with constant amplitude, and when the operator stops stepping on the pedal, the supply of the drive current is stopped. The amplitude of the drive current is constant from the start to the stop of supply.
On the other hand, the main unit 1 of the ultrasonic surgical apparatus according to the present embodiment supplies a drive current given with predetermined modulation to the handpiece 2 when an operator steps on a pedal of the foot switch 3. In particular, in the present embodiment, an amplitude-modulated drive current is supplied to the handpiece 2.
With reference to FIGS. 3 to 23, various examples of waveform patterns applicable to the ultrasonic surgical apparatus according to the present embodiment are described hereunder. These waveform patterns indicate modulation variations in the drive current to be supplied to the transducer 2a of the handpiece 2. These waveform patterns may be preset or selected for each use.
It should be understood that the waveform patterns described hereunder are of AC current, and thus, in the figures, the waveform patterns are created by modulating the amplitude of an AC signal (current signal) having a frequency, for example, of 27 KHz, centering on a central line C at which amplitude is 0 (zero).
In order to supply the drive currents shown in FIGS. 3 to 5 to the transducer 2a of the handpiece 2, the CPU 22 outputs a voltage data to the D/A converter 28, the voltage data corresponding to an amplitude waveform pattern of a current value preset by an operator or preset according to the type of the handpiece 2. The D/A converter 28 supplies a signal corresponding to the value of the received waveform pattern data to the comparator 29. The comparator 29 then supplies an output signal to the multiplier 30, according to the difference between the set value of the waveform pattern data and an absolute value of a detected drive current. The multiplier 30 multiplies the output signal with a signal from the DDS 26, by which amplitude-modulated drive currents having waveform patterns as shown in FIGS. 3 to 5 are created, in which amplitude varies relative to a time base.
FIGS. 6 to 8 show examples of waveform pattern data PD which are outputted from the CPU 22 to the D/A converter 28 to output the respective drive currents shown in FIGS. 3 to 5. Each of the waveform patterns has continuous multiple pulses of a predetermined duty ratio. In each of the figures, the horizontal axis represents a time base and the vertical axis represents a set value of a drive current, i.e. a set value of a maximum output. The set value of a drive current indicates a ratio to 100% output of current supplied to the handpiece 2 from the main unit 1. Thus, since a waveform pattern is set so that a set value is varied with time, a current signal having specific frequency, for example, of 27 KHz is modulated in amplitude so as to be suppressed to the level of set value according to the waveform pattern, and supplied to the transducer 2a of the handpiece 2. The CPU 22 and the D/A converter 28 constitute a principal part of modulating means for effecting modulation of a drive current.
It should be understood that the duty ratio “T1/(T1+T2)” may be 5% to 100%, preferably, 5% to 50%, and that the period T may be 0.1 to 1 second, preferably, 0.4 to 1 second. These numerical values are based on the experiments carried out by the inventors of the present invention.
One example of the results of the experiments is shown in
Because each pulse output of such waveform patterns has a high output period T1 having 100% output of drive current amplitude, the incision capability of the handpiece 2 is not varied. Further, because each pulse output has a low output period T2 having non-100% output of drive current amplitude, the overheating of the treatment device 5 of the handpiece 2 can be suppressed. In particular, generation of frictional heat due to ultrasonic vibration of the probe 9 can be prevented. Accordingly, even when the treatment device 5 is brought into touch with living tissue during operation, transformation is unlikely to occur in the living tissue since the temperature of the treatment device 5 is not high.
FIGS. 9 to 20 show other examples of output waveforms of a drive current supplied to the handpiece 2, and waveform patterns supplied to the D/A converter 28 from the CPU 22.
As shown in FIGS. 21 to 23, after starting treatment, a waveform pattern may be changed between the one in an initial predetermined period Ta and the one in a subsequent period Tb. FIGS. 21 to 23 show examples of the waveform patterns in which waveform patterns are changed in mid-course.
A waveform pattern is changed in mid-course depending on conditions, such as the contents of treatment carried out by an operator, and the way of using treatment devices. For example,
In a twelfth waveform pattern shown in
The pattern shown in
Contrarily, for the cases shown in
Setting of the various pattern data PD described above have been automatically carried out according to the type of the handpiece 2 determined by the HP determining circuit 21, however, an operator may often wish to finely control a waveform pattern or to change the setting to another setting value. In such cases, an operator may allow an automatically selected set value to be indicated on the display 18 with a function switch, not shown, of the front panel 11 shown in
In the description provided above, the waveform pattern data has been stored in the ROM 22a connected to the CPU 22, however, the data may be stored in a rewritable memory, such as a flash memory.
It should be understood that, according to the type of the handpiece 2, modification may be made in the process for changing the maximum amplitude, i.e. 100% output, of a drive current and the frequency of the drive current. For example, an arrangement may be made wherein a waveform pattern data PD of a drive current to be supplied to the handpiece 2 is recorded in advance into a ROM incorporated in the handpiece 2, and the ROM data is transferred to the main unit 1 to allow the main unit 1 to control the drive current based on the ROM data.
Moreover, in the waveform pattern examples described above, either amplitude or a duty ratio has been changed, however, as shown in
Specifically, as shown in
As described above, according to the ultrasonic surgical apparatus of the first embodiment, ultrasonic treatment (incision, coagulation, etc.) can be effected based on a drive current which is controlled in its amplitude so that frictional heat due to the vibration of the probe 9 may not be excessively increased during the treatment. Thus, unlike the conventional ultrasonic treatment based on a drive current having constant amplitude, the inventive device is capable of adequately controlling heat required for the treatment. For this reason, such inconvenience can be avoided as the occurrence of undesired incision prior to coagulation due to the transfer of heat to the inside of a portion to be treated. Particularly, while ensuring amplitude of a drive current at a required level, a time zone, in which amplitude is to be reduced, is set by an adequate mode. The time zone where the amount of heat to be generated is suppressed, efficiently functions by permitting previously generated heat to be sufficiently diffused to the inside. Thus, heat transfer to a treatment device is suppressed to control the timing of incision and coagulation, so that incision can be performed while coagulating the portion to be treated. In particular, incision can be performed substantially in parallel with coagulation.
In addition, incision capability based on the required level of amplitude can also be sufficiently ensured. That is, a good balance can be achieved between suppression of heat generation in a treatment device and retaining incision capability.
Furthermore, according to the present embodiment, incision treatment can be adequately effected according to the type of the handpiece 2.
With reference to
In the circuit configuration shown in
The handpiece 2 is incorporated with a ROM 2c, and the main unit 1 is provided with a ROM data read circuit 41 which is connected to the ROM 2c through the connector cable 15. The ROM data read circuit 41 is connected to the CPU 22 to supply the waveform pattern data PD stored in the ROM 2c thereto. The waveform pattern data PD stored in the ROM 2c are the ones shown in
In addition to the treatment devices utilizing ultrasonic waves, other treatment devices may sometimes be used together. In consideration of such cases, a ROM incorporated into a treatment device may be made capable of recording thereinto an information data of “No modulation”.
It should be understood that, alternatively, an arrangement may be so made that, depending on the contents or the like of surgery, an operator can finely control a waveform pattern determined in advance according to the type of the handpiece 2. The waveform pattern data PD have been set and recorded in the ROM 22a or 2c according to respective types of the handpiece 2. Thus, when the handpiece 2 is connected to the main unit 1, the CPU 22 indicates on the display 18 a minimum value of a drive current and a duty ratio determined according to the type of the handpiece 2.
Accordingly, an operator can finely control and change the displayed individual values by operating the switches 17a and 17b. Then, by inputting a command (not shown) for registering a set value, a waveform pattern can be stored in the RAM of the CPU 22. The display 18 serves as one for indicating and setting a minimum value of a drive current and a duty ratio.
For example, for the waveform patterns shown in FIGS. 6 to 8, an operator may temporarily permit a preset minimum value ratio in the period T2 to be indicated on the display 18 by inputting a predetermined command to the CPU 22. Then, the operator may change and finely control the minimum value ratio by operating the switches 17a, and 17b. Further, an operator may temporarily permit a preset duty ratio to be indicated on the display 18 by inputting a predetermined command to the CPU 22. Then, the operator may change and finely control the duty ratio by operating the switches 17a and 17b. The change of a duty ratio involves, for example, a ratio (%) of the period T1 to one cycle, or a ratio (%) of the period T2 to one cycle. For a sine waveform pattern as well, an arrangement may be so made that a duty ratio can be changed. For example, as shown in
In the examples described above, the preset waveform pattern data PD, or finely controlled waveform pattern data PD according to respective types of the handpiece 2 have been supplied to the CPU 22. Alternatively, an arrangement may be so made that an operator can optionally set a waveform pattern data PD depending on the contents or the like of surgery.
With reference to
A front panel 11A shown in
For example, since a maximum value is determined according to the type of the handpiece 2, an operator may allow the display 18A to indicate a ratio of “50” (%) as a minimum ratio of current amplitude to a maximum output value. Then, the operator may allow the display 18B to indicate a ratio of “60” (%) as a duty ratio, i.e. a ratio of maximum output to one cycle. When a command (not shown) for registering set value is inputted in this state, the waveform pattern data PD can be stored in the RAM of the CPU 22.
In this way, an operator may be able to optionally set a waveform pattern data PD of a drive current of the handpiece 2, depending on the contents or the like of surgery.
With reference to FIGS. 28 to 31, a fourth embodiment of the ultrasonic surgical apparatus according to the present invention is described.
An arrangement may be made such that an operator can optionally select a waveform pattern data PD of a drive current of the handpiece 2 depending on the contents or the like of surgery. FIGS. 28 to 30 illustrate an example in which a waveform pattern is optionally selected.
Similar to the front panel 11 shown in
A process flow which is performed when an operator selects a waveform pattern is described hereunder with reference to
When the selection switch 51 is depressed initially, a first pattern number is indicated (blinked) (step S1) from among a plurality of waveform patterns recorded on a memory, such as a ROM, according to a predetermined sequence. In this case, as shown in
When the selection switch 51 is depressed, the determination at step S3 results in YES, and control returns to step S1 to blinkingly indicate a next pattern number, i.e. “PA2” in this case. When the selection switch 51 is further depressed, step S2 results in NO and step S3 results in YES, so that control again returns to step S1 to blinkingly indicate the next pattern number, i.e. “PA3” in this case. In this way, at step S1, pattern numbers of the waveform patterns stored in the ROM or the like are sequentially indicated (see state 55 in
If the depression of the memory switch 52 takes place, which means an operator's confirmation of entry of a waveform pattern, step S2 results in YES. Then, a registration process is performed (step S4) for storing the pattern number in a memory, such as a RAM. Control then proceeds to step S5 in which the entered pattern number is lit on the display 18 (see state 56 in
For example, if a selected and entered pattern number corresponds to a waveform pattern shown in
As described above, an operator can optionally select a waveform pattern of a drive current of the handpiece 2 depending on the contents or the like of surgery, while the pattern number of a selected waveform pattern is stored in a RAM. Since the waveform pattern data PD corresponding to the stored pattern number is outputted to the D/A converter 28 from the CPU 22, the handpiece 2 turns out to be the one which provides good usability for an operator.
With reference to FIGS. 32 to 34, a fifth embodiment of the ultrasonic surgical apparatus according to the present invention is described below.
An arrangement may be made such that an operator can optionally set a waveform pattern of a drive current of a handpiece 2 depending on the contents or the like of surgery.
FIGS. 32 to 34 illustrate an example in which a waveform pattern data is optionally set.
Similar to the front panel 11 shown in
A process flow for an operator to optionally set a waveform pattern is described with reference to
The CPU 22 determines (step S11) first as to whether or not the selection switch 62 has been depressed, and then stands by until the selection switch 62 is depressed. With the depression of the selection switch 62, a next pattern number is blinkingly displayed at step S12 (see state 72 in
Upon depression of the entry switch 64, determination at step S13 results in YES, so that control proceeds to step S14 to light up a registration pattern number, that is, a pattern number to be registered (see state 73 in
Then, being in a state capable of performing a waveform pattern setting process, the CPU 22 executes setting process (steps S15 and S16) in which an operator can set a waveform pattern using the switches 63a, 63b, 63c and 63d and the entry switch 64.
When the CPU 22 is in the setting process of a waveform pattern, an operator can set a waveform pattern in the following procedures. The switch 63a serves as a button for instructing output decrease, and the switch 63b serves as a button for instructing output increase. The switch 63c serves as a button for instructing decrease in output time, and the switch 63d serves as a button for instructing increase in output time.
For example, assuming that a drive current of 100% output is to be outputted initially for 20 ms (millisecond which also applies to the following description), the initial output is rendered to be 100% by using the switch 63b, and the output time indicated on the display 18C is changed from 0 ms to 20 ms, for example, by using the switch 63d. When the entry switch 64 is depressed at this stage, the output of the first 20 ms period is indicated on the display 18C as an initial waveform pattern shown by an indication 74a in
Similarly, by using the switches 63a, 63b, 63c and 63d, the output and the output time of a second period are set. For example, when a drive current of 70% output with an output time of 30 ms is set, followed by depression of the entry switch 74, a waveform pattern shown by an indication 75a in
The setting process is carried out in this way. During the setting process (step S15), a determination is constantly made (step S16) as to whether or not the memory switch 64 has been depressed for confirming the end of pattern setting. If the memory switch 64 has not been depressed, the determination at step S16 results in NO, and control returns to step S15.
If the entry switch 64 is depressed, the determination at step S16 results in YES, and control proceeds to step S17 where the contents of the set waveform pattern are lit up (see state 77 in
As described above, an operator can optionally set a waveform patter of a drive current of the handpiece 22 depending on the contents or the like of surgery, and the set waveform pattern is stored in a RAM. Since the stored waveform pattern data PD is outputted from the CPU 22 to the D/A converter 28, the handpiece 2 turns out to be the one providing good usability for an operator.
With reference to FIGS. 35 to 37, a sixth embodiment of the ultrasonic surgical apparatus according to the present invention is described.
An arrangement may be so made that an amplitude-modulated current signal is outputted according to a predetermined trigger signal. Specifically, an arrangement may be so made that an operator can detect timing for using a handpiece 2 with a predetermined trigger signal, so that a predetermined amplitude-modulated drive signal (current) is outputted. Various examples of trigger signals are described hereunder.
Hereunder is described an example of a temperature sensor that can be implemented in this embodiment. In this example, an output of the temperature sensor serves as such a trigger signal.
With this configuration, the CPU 22 supplies a drive current of 100% output when a pedal of the foot switch 3 is stopped on. When the temperature of the probe 9 thereafter becomes equal to or more than a predetermined temperature, i.e. the trigger temperature, of 180 degrees in centigrade, for example, the CPU 22 outputs the waveform pattern data PD as described above to the D/A converter 28, so that an amplitude-modulated current signal is supplied to the handpiece 2.
Accordingly, a drive current of 100% output comes to be supplied until the temperature of the treatment device 5 of the handpiece 2 becomes equal to or more than a predetermined temperature.
A modification is described with reference to FIGS. 58 to 60.
The above sixth embodiment can be implemented by making a modification thereto as follows. In the sixth embodiment, heat generation caused at a treatment device by the frictional heat resulting from ultrasonic vibration of the probe 9, has been controlled based on an ideal temperature curve. Alternatively, instead of setting this ideal temperature curve, an Upper limit of generated heat temperature may be set as a target value, and then a duty ratio or amplitude of a waveform pattern data PD may be controlled so that generated heat temperature follows the target value. This amplitude corresponds to the amplitude of voltage inputted to the D/A converter 28.
One example of this control is described in detail hereunder with reference to FIGS. 58 to 60. As shown in
More specifically, the CPU 22 stands by while determining as to whether or not the foot switch 3 is on (step S31). When the foot switch 3 is determined to be on (time T10 in
On the other hand, when the treatment temperature becomes equal to the set temperature Tset (YES at step S33, and time T11 in
Then, the CPU 22 again monitors a detection signal from the temperature detection circuit 84 to compare actual treatment temperature with a set temperature (target temperature) (steps S35 and S36). In particular, the CPU 22 determines whether the treatment temperature is larger than the set temperature (step S36A), whether the treatment temperature is less than the set temperature (step S36B), and whether the temperature is equal to the set temperature (step S36C). Depending on the result of this determination, a command is issued to change or maintain a duty ratio (step S37). Particularly, when the treatment temperature is larger than the set temperature, the CPU 22 sets a duty ratio which decreases at a specific rate for the specific period Tα (step S37A). When the treatment temperature is less than the set temperature, the CPU 22 sets a duty ratio which increases at a specific rate for the specific period Tα (step S37B). When the treatment temperature is equal to the set temperature, the CPU 22 sets a duty ratio which maintains the ratio at the time for the specific period Tα (step S37C). The thus set duty ratio is outputted (step S38). The CPU 22 thereafter repeats the processes of steps S35 to S38 described above until a determination to turn off the foot switch 3 is made (step S39).
Thus, a duty ratio of a waveform pattern PD is changed as shown in
In this way, temperature of a treatment device can be maintained at a desired value with the relatively simple control, i.e. to start control of a duty ratio when the temperature of the treatment device has reached a set temperature. This simple duty ratio control owes to a unique principle of an ultrasonic surgical apparatus, i.e. to perform incision and coagulation by using the frictional heat of the probe 9. This device is different from a surgical instrument, such as an electric cautery, in which treatment temperature drastically increases. In case of an ultrasonic surgical apparatus, its simplicity in duty ratio control owes to the smallness of a time constant of temperature transfer, and the readiness that a duty ratio, whether it is small or large, can be reflected, as it is, to treatment temperature. Such control of a duty ratio allows treatment temperature to be maintained around a set temperature. It should be understood that the temperature curve in
It should also be understood that in the treatment temperature control described above, temperature can be set at any value, and that an appropriate value within a range, for example, of 100 to 150 degrees in centigrade may be set to attain sufficient coagulation. As described above, as an alternative to a duty ratio of a waveform pattern data PD, its amplitude (voltage) may be controlled. In particular, by changing amplitude (VH, VL) shown in
Additionally, the timing for transferring control to the change of duty ratio or amplitude, should not necessarily coincide with the time when treatment temperature becomes equal to a set temperature. For example, the transfer of control to the change of duty ratio or amplitude may be performed at the time when a formula expressed by “treatment temperature=set temperature−predetermined value β” is satisfied. This predetermined value β is provided in view of the time constant of heat transfer of a treatment device described above. By this value β, the transfer of control to the change of duty ratio or amplitude can be performed a little earlier, so that overshooting of treatment temperature with respect to a set temperature can be surely suppressed. This predetermined value β, for example, may be only a few degrees in centigrade.
Instead of controlling a duty ratio or amplitude at the time when treatment temperature has become equal to a set temperature as described above, the ideal temperature profile shown in
With reference to
A temperature sensor 82 may be provided in a gripper 10 rather than in a probe 9.
In the example provided above, a drive current of constant amplitude has been outputted until a trigger signal is generated, and upon generation of a trigger signal, a predetermined amplitude-modulated drive current has been outputted. Alternatively, a first amplitude-modulated drive current may be outputted until a trigger signal is generated, and upon generation of a trigger signal, a second amplitude-modulated drive current, which is different from the first amplitude-modulated drive current, may be outputted.
With reference to
A time-out signal may be used as a predetermined trigger signal.
Is should be understood that the period Ta1, i.e. a period from time t1 to t2, may be set according to a value of a drive current which is outputted when the foot switch 3 is stepped on. In the case shown in
With reference to
When a pedal of the foot switch 3 is stepped on, a timer for counting the predetermined period Ta1 (or Ta11) is turned on, or started up (step S21). This timer may be a software timer counted by the CPU 22, or a hardware timer. Subsequently, a specific drive current, e.g., a digital data corresponding to the 100% drive current in
A determination is the made (step S23) as to whether or not the time set at the timer has run out. If not, control returns to step S22. If the time has run out, the determination at step S23 results in YES. The CPU 22 then outputs (step S24) a waveform pattern data PD corresponding to a set amplitude-modulated drive current to the D/A converter 28 from the CPU 22.
As shown in
With reference to FIGS. 43 to 45, a tenth embodiment of the ultrasonic surgical apparatus according to the present invention is described.
An output signal of an output switch provided at a handpiece 2 may be utilized as a predetermined trigger signal.
A difference from the configuration shown in
In this arrangement, when a pedal of the foot switch 3 is stepped on at time t21, the CPU 22 outputs a 50% drive current, for example, for an initial period after time t21. Thereafter, when the output switch 91 is turned on at time t22, the CPU 22 outputs the above waveform pattern to the D/A converter 28, so that an amplitude-modulated drive signal may be supplied to the handpiece 2.
Accordingly, an amplitude-modulated drive current is outputted to the handpiece 2 only when an operator uses the handpiece 2 to hold living tissue.
With reference to
An output signal of an angle sensor provided at a handpiece 2 may be used as a predetermined trigger signal.
A difference from the configuration shown in
In this arrangement, the timing when an angle made between the two pieces of the operation handle 8 becomes equal to or less than a preset angle, serves as a trigger signal. With this trigger signal, the CPU 22 outputs the waveform pattern data PD as described above to the D/A converter 28, so that an amplitude-modulated drive current is supplied to the handpiece 2.
In the above description, an example has been given in which linearly arranged light receiving elements are used. Alternatively, a single light receiving element may be given at a predetermined angle position to notify the CPU 22 of a presence of an output.
Thus, an amplitude-modulated drive current comes to be outputted to the handpiece 2 only when an operator uses the handpiece 2 to hold living tissue.
With reference to
An output signal of a power sensor provided in a handpiece 2 may be utilized as a predetermined trigger signal.
A difference from the configuration shown in
In this arrangement, the timing when the operation handle 8 is operated by an operator to a physical power equal to or more than a predetermined value, serves as a trigger signal. With this trigger signal, the CPU outputs the waveform pattern data PD described above to the D/A converter 28, so that an amplitude-modulated drive current is supplied to the handpiece 2.
As a result, an amplitude-modulated drive current is outputted to the handpiece 2 only when an operator uses the handpiece 2 to hold living tissue with a predetermined physical power.
With reference to
Impedance of a handpiece 2 may be used as a predetermined trigger signal.
In incision treatment, for example, a living tissue portion is held between a probe 9 and a gripper 10. Since impedance of the handpiece 2 changes by holding living tissue, the change of the impedance can be used as a trigger signal.
A difference from the configuration shown in
In this arrangement, the timing when the operation handle 8 is operated by an operator for a predetermined operation that changes impedance, serves as a trigger signal. With this trigger signal, i.e. with the change of impedance, the CPU 22 outputs the waveform pattern data PD described above to the D/A converter 28, so that an amplitude-modulated drive current is supplied to the handpiece 2.
With reference to
An arrangement may be so made that a preset value of a drive current, i.e. a duty ratio, is changed according to detected impedance.
As a modification, amplitude modulation may be carried out as shown in
In this way, an amplitude-modulated drive current is outputted to the handpiece 2 only when the handpiece 2 is used by an operator to hold living tissue.
As described above, the CPU 22 outputs a waveform pattern data to the D/A converter 28, so that an amplitude-modulated drive current is supplied to the handpiece 2 only when an operator uses the handpiece 2 for incision treatment or the like. In the examples provided above, impedance, an output switch, an angle, physical power and the like have been introduced as a trigger signal, however, other alternatives may be used as a trigger signal.
With reference to
An RF-ID tag may be stuck onto a handpiece 2 with information on the handpiece 2 being recorded on the RF-ID tag. In this case, an arrangement may be so made that an operator and/or nurses can recognize that a handpiece 2 carries an RF-ID tag when the handpiece 2 is placed in a tray or the like.
For this purpose, as shown in
If an operator and/or nurses can recognize that the handpiece 2 is provided with the RF-ID tag 62, they can bring the RF-ID tag 62 close to a reader to transmit information stored therein, such as a waveform pattern data, to the CPU 22 in the main unit 1, so that the main unit 1 can output a waveform pattern data suitable for the handpiece 2.
In order for an operator and/or nurses to recognize that the handpiece 2 carries the RF-ID tag 62, an arrangement may be so made that the FR-ID tag 62 is provided at a position that can be seen when the handpiece 2 is placed in the tray 61 with whichever side thereof being turned up. For example, as shown by a dotted line in
Similar to the foregoing embodiments, according to the fifteenth embodiment, use of the waveform pattern data of a drive current as described above may realize an ultrasonic surgical apparatus which does not allow deterioration of incision capability, while suppressing heat generation of a treatment device.
With reference to
In order to suppress heat generation of a treatment device, the ultrasonic surgical apparatus according to the sixteenth embodiment utilizes frequency modulation for the modulation of a drive current.
An electric circuit configuration of the ultrasonic surgical apparatus according to the present invention is substantially the same as the electric circuit configuration shown in
The phase comparator 27 supplies, in the first place, an up signal or a down signal to the U/D counter 25 so that a phase difference turns to zero, while the CPU 22 changes a value of the up signal or the down signal to be supplied, so that the frequency of a drive current is offset as described above. Further, the DDS 26 outputs a frequency signal based on a value set in the U/D counter 25, while the CPU 22 changes the value set in the U/D counter 25 so that the frequency of a drive current is offset as described above. In particular, the CPU 22 is capable of controlling the frequency of a drive current to periodically repeat increase and decrease centering on the center frequency fr. In this way, in the impedance and phase characteristics shown in
The transducer 2a vibrates with the best energy efficiency when a drive current having the resonance frequency fr is supplied to the handpiece 2. However, when the handpiece 2 is supplied with a drive current whose frequency f varies with respect to the center frequency, repeating increase and decrease as shown in
As shown in
As shown in
Thus, according to the sixteenth embodiment, the frequency f can be periodically varied within a range including the resonance frequency fr. In this way, an ultrasonic surgical apparatus which does not reduce the incision capability but suppresses heat generation of a treatment device can be achieved.
It should be understood that, in the sixteenth embodiment as well, an arrangement may be so made that frequency modulation is performed in response to a preset trigger signal as described in the foregoing embodiments. For example, frequency of a drive current may be changed by using a trigger signal, such as an output from a temperature sensor and a time-out signal from a timer as described referring to FIGS. 34 to 53.
It should also be understood that frequency modulation may be performed in accordance with the type of a handpiece.
Various embodiments and modifications have been described with respect to the ultrasonic surgical apparatus and the method for driving the ultrasonic surgical apparatus according to the present invention. Such devices and methods according the present invention are not necessarily limited to the ones described herein, but may include those which can be implemented with further modification without departing from the spirit of the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2004-351801 | Dec 2004 | JP | national |
