JP4166458B2 - Method for driving an ultrasonic system to improve the capture of blade resonance frequency at start-up - Google Patents

Description

Related applications
The present invention relates to US Provisional Patent Application No. 60 / 241,895, filed Oct. 20, 2000, which has the same title as the present invention and is incorporated herein by reference. , Claim priority based on this.
[0001]
BACKGROUND OF THE INVENTION
The present invention relates generally to the field of ultrasound equipment, and more particularly to a method for improving the ability of an ultrasound system to sweep and lock to a resonant frequency of a blade that is relatively heavily loaded at start-up. .
[0002]
[Prior art]
It is known that an electrosurgical scalpel and laser can be used as a surgical device to perform two functions of simultaneously incising and hemostasis soft tissue by cauterizing tissue and blood vessels. However, such devices produce vaporization and fuming and splashing due to the use of extremely high temperatures to form a solidified state. Furthermore, the use of such a device often forms a relatively wide area of thermal tissue damage.
[0003]
Cutting and cauterizing tissue with a surgical blade that vibrates at high speed with an ultrasonic drive mechanism is also well known. One example of a problem associated with such an ultrasonic cutting device is unadjusted or undamped vibration and heat, and the resulting material fatigue. Attempts have been made in the past to control the heating problem by including a cooling process of the system with a heat exchanger for cooling the blades within the environment of the operating space. For example, in one example of a known system, the ultrasonic cutting and tissue fragmentation system requires a cooling system with a circulating water jacket and means for irrigation and aspiration of the cutting site. Another known system requires the supply of cryogenic fluid to the cutting blade.
[0004]
It is known to limit the current supplied to a transducer as a means to limit the heat generated in the transducer. However, this can cause insufficient power to be supplied to the blade when the patient needs the most effective treatment. US Pat. No. 5,026,387, issued to Thomas, which is assigned to the assignee of this patent application and is incorporated herein by reference, controls the driving energy supplied to the blade to control the coolant. A system for adjusting fever in an ultrasonic surgical cutting and hemostasis system without use is disclosed. In the system according to this patent, the ultrasonic generator is equipped with an ultrasonic generator that generates an electrical signal of a specific voltage, current and frequency of, for example, 55,500 cycles per second. The generator is connected to a hand piece via a cable, which contains a piezoelectric ceramic element to form an ultrasonic transducer. In response to a foot switch connected to the generator by a switch on the hand piece or another cable, the generator signal is fed to the transducer, causing longitudinal vibrations in the element. A structure connects the transducer to the surgical blade, which causes the surgical blade to vibrate at an ultrasonic frequency when a signal from the generator is supplied to the transducer. Furthermore, since the structure is configured to resonate at a predetermined frequency, the operation started by the transducer can be amplified.
[0005]
The signal supplied to the transducer is controlled to provide an output to the transducer as appropriate in response to continuous or periodic sensing information about the blade loading condition (tissue contact or retraction). As a result, the apparatus reaches from a low-power idling state to a high-power cutting state that can be selected automatically depending on whether or not the surgical knife is in contact with the tissue. The third high power coagulation mode can be selected manually with automatic return to idling power level when the blade is not in contact with tissue. Since this ultrasonic power is not continuously supplied to the blade, sufficient energy can be supplied to the tissue for incision and cauterization as needed while reducing ambient heat generation.
[0006]
The control system in the Thomas patent is an analog type. A phase lock loop (including voltage controlled oscillator, frequency divider, power switch, matching network and phase detector) stabilizes the frequency supplied to the hand piece. Parameters such as frequency, current, and voltage supplied to the hand piece vary with the load on the blade, and the microprocessor controls the amount of output by sampling them.
[0007]
The output versus load curve in a generator in a typical ultrasonic surgical system as described in the Thomas patent has two parts. The first part has a positive slope indicating a steady current supply where the output increases with increasing load. The second part has a negative slope indicating a steady or saturated output voltage where the output decreases with increasing load. The current adjusted corresponding to the first part is fixed by the design of each electronic component, and the voltage of the second part is limited by the maximum output voltage in the design. The above configuration is inflexible because the output-to-load characteristics at the output of such a system cannot be optimized for various hand piece transducers and ultrasonic blades. The performance of conventional analog ultrasound output systems for surgical devices is affected by component tolerances and variability in the electronics of the generator due to operating temperature changes. In particular, temperature changes cause a variety of changes in important system parameters including frequency lock range, drive signal level, and other system performance measurements.
[0008]
In order to operate the ultrasonic surgical system in an efficient manner, the resonant frequency is positioned by sweeping a range of signal frequencies supplied to the hand piece transducer at startup. When this position is found, the generator phase lock loop is locked to its resonant frequency and the transducer current is continuously monitored for voltage phase angle to drive the transducer at that resonant frequency. To keep the device in resonance. Important functions in such systems are maintaining the transducer in resonance in the presence of a load and temperature changes that change the resonant frequency. However, these conventional ultrasonic drive systems have little or no flexibility for adaptive frequency control. Such flexibility is important in the system's ability to identify unwanted resonances. In particular, these systems can only search in response to resonance in one direction, i.e., these search patterns are fixed with increasing and decreasing frequencies. This system cannot (i) jump over irrelevant resonance modes, or any heuristic decisions such as which resonances to jump over or lock, and (ii) at the appropriate frequency The output cannot be reliably supplied only when the locking is performed.
[0009]
Furthermore, prior art ultrasonic generator systems have little flexibility in amplitude control that allows the use and decision operation of adaptive control algorithms in the system. For example, these fixed systems lack the ability to make heuristic decisions on output drive elements, such as current or frequency, based on the current on the load and / or voltage phase angle on the blade. This also limits the system's ability to set an optimum transducer drive signal level corresponding to a certain efficient performance that extends the useful life of the transducer and establishes safe operating conditions for the blade. Furthermore, this lack of control over amplitude and frequency reduces the system's ability to assist in diagnostic testing and overall troubleshooting for the transducer / blade system.
[0010]
The ultrasonic system described in US patent application Ser. No. 09 / 693,621, filed Oct. 20, 2000, which is incorporated herein by reference, sweeps the output drive frequency to produce an ultrasonic transducer. And the ability to monitor the blade frequency response, extract parameters from this response, and use these parameters as system diagnostic information. This frequency sweep and response measurement mode is achieved via a digital code, whose output drive frequency can be graded with high resolution, accuracy, and repeatability that do not exist in prior art ultrasound systems.
[0011]
[Problems to be solved by the invention]
There are problems associated with existing ultrasound systems, for example, it may be difficult to start the system when the blade is in a particular load condition. The blade is loaded when the blade is in contact with the skin tissue or as a result when debris or the like is sandwiched between the blade and the blade sheath. The main disadvantage that users of such ultrasonic generators are complaining about is that they cannot be started under conditions of moderate to heavy loads. Also, in the presence of a light or moderate load, debris between the blade and blade sheath will load the blade and reduce the blade's starting performance or the starting ability of the blade in a free normal condition. there is a possibility.
[0012]
An acoustic system with a minimum attenuation level is heavily loaded, i.e. it can start operating more easily than a system with attenuation. Furthermore, the electronic components used to drive such transducers work best when used with hand pieces / blades that can be easily started. Also, an acoustic system that is heavily loaded with a relatively high voltage / current value operates relatively easily and can operate even larger than with a relatively low voltage / current value. The ability to lock on can be increased. However, it is not possible to start using a hand piece / blade that is heavily loaded at low voltage. Further, handpieces / blades that are heavily loaded after having continuously resonated can continue to resonate.
[0013]
In general, the voltage applied to the transducer is relatively low when making an initial attempt to position the blade resonance by sweeping over a range of frequencies. This causes the following conditions. First, the start-up in a loaded condition is limited by insufficient current feedback signal levels. In this case, the blade and load impedance values are such that the voltage level applied to the hand piece at resonance produces a current feedback signal that is too small to be read by a detection circuit in the generator.
[0014]
Second, another limiting factor is “sticktion”, ie, the blade sticks against the load. In this case, the energy supplied to the hand piece is insufficient to initiate blade operation and the hand piece / blade responds as if there is a very large mechanical load. This condition results in a highly damped hand piece / blade, where the phase angle between current and voltage does not cross zero, and resonance detection by zero crossing is not possible. On the other hand, when the blade is in operation, this “static inertia” force or “static frictional” force is less than its starting value. At this point, the drive signal can be decreased by increasing the load without disabling the resonance lock. Yet another limiting action is sticking on the blade, ie, blood and other debris sticking between the blade and the sheath, increasing the load on the blade. Furthermore, this adhesion itself imposes a load on the blade and reduces the ability of the blade to effectively start in a loaded state.
[0015]
In addition, since the primary resonance frequency of the blade is unknown at an early stage, the generator often performs sweeping over a considerably wide frequency range. This “wide sweep” approach has several disadvantages. First, it takes time to position the resonance. If the main resonance position is at the other end when the sweep is started at one end of the sweep range, a considerable amount of time is spent until the main resonance position is found. Second, secondary resonance (unrequired resonance) can be mistaken for primary resonance. Because there are other blade resonances (referred to herein as secondary resonances), secondary resonances can be detected before primary resonances are detected by the frequency sweep described above. There is sex. By limiting this sweep range, the possibility of accidental locks on secondary resonances can be reduced. However, such limitation of the sweep range complicates the blade configuration and narrows the degree of freedom in order to narrow the allowable primary resonance range in the blade.
[0016]
Furthermore, another problem with conventional ultrasound devices is that the stability of the frequency control lock relative to the output is affected by transducer "ringing" as the frequency approaches the resonance region of the blade.
[0017]
[Means for Solving the Problems]
The present invention is a method for improving the ability of an ultrasound system to sweep and lock against the resonant frequency of a heavily loaded blade during startup. This can be achieved by supplying a high drive voltage or high drive current. By increasing the drive signal for the hand piece, an improved and clearer resonance as seen with a spectrum analyzer is obtained. That is, in a state where a load is applied, the maximum phase is further increased (more inductive) due to the increased drive signal, the minimum impedance is further reduced, and the maximum impedance is further increased. Therefore, the increase in excitation drive signal for the hand piece / blade at start-up significantly mitigates the limiting factors associated with the ultrasound generator, thereby increasing the maximum load tolerance at start-up.
[0018]
According to the present invention, the blade is driven by a progressively stronger signal, which allows a faster and more accurate recognition of the resonance in the actual operation of the blade, and makes another resonance the desired resonant vibration. Accidental mistakes with numbers can be avoided. Undesired vibration modes, such as modes across resonance (ie, vibrations along an axis perpendicular to the longitudinal axis of the hand piece / blade vibration) result in a substantial level of energy levels that cause the blades to vibrate. Not excited until. This action can be advantageously used to initially drive the blade ultrasonically at a very low level within the known resonance frequency range of the blade. Resonance during the operation of the target blade can be recognized by measuring the resonance impedance during the sweep process, and the impedance value at this resonance is higher than that of another unwanted resonance that requires more energy to resonate efficiently. Is more robust and has a high probability of identification. If the resonance position is not determined at all, another sweep process is performed with the drive strength increased. This method is continuously repeated at higher drive levels until blade resonance is obtained.
[0019]
In one example of an embodiment of the present invention, a moderate to strong drive signal (rather than starting a sweep with a low level drive signal) is supplied to the blade during the sweep process to position the resonant frequency. If a large number of resonances are detected, the sweep is repeated progressively at lower levels until a primary resonance is seen. Further, the method using this embodiment of the present invention improves the starting performance of the ultrasound system while minimizing transducer ringing, which has a high system Q value (ie, minimum system impedance value) and phase-vibration. This is particularly noticeable in the “no-load” state when the phase response gradient in the few plots is large. Yet another advantage of initiating sweeps at higher drive levels is the ability to obtain a more robust resonant frequency in heavily damped blades that allows for faster resonant frequency recognition and locking. .
[0020]
In another embodiment of the present invention, a progressively widening sweep process is performed and a drive signal whose intensity changes based on the observed resonance is used. Such a combination can provide both the benefits of a narrow sweep that saves time and the benefits of a high power that ensures that the blade can resonate. For example, a narrow sweep at a high drive level is initially performed, and if no resonance is found, the sweep is further expanded. When a large number of resonances are detected, the signal level is lowered. This type of sweep process facilitates quick recognition of the desired resonant frequency in the damped blade without accidentally driving the blade at an undesirable resonant frequency.
[0021]
In another embodiment of the invention, the sweep process for the resonance starts at the most central or ideal resonance frequency of the blade. If the position of resonance is not determined, it will be very close to a frequency range very close to the ideal resonant frequency at a constant increased distance from the center frequency of the blade or the ideal frequency position. The frequency is inspected by the sweep process. Even in this case, if no resonance is observed, the frequency of the position slightly outside of the initial frequency range is inspected. If no resonance is found at all, the swept frequency range is expanded and the resonance frequency is searched again. In order to save time, the frequency already performed in the sweeping process of the frequency that spreads in a signal manner is skipped, and only the uninspected frequency within the expanded range to be re-inspected is concentrated. As a result, most blades have a primary resonance frequency that is statistically close to the center frequency or the ideal frequency position, so that the recognition process of this resonance frequency is accelerated.
[0022]
The method of the present invention provides an ultrasound system that has starting capability in the presence of even greater loads. This method also provides a system that has the ability to start more quickly and lock to the blade's resonant frequency more easily, eliminating problems associated with “gunk” or debris that has entered between the blade and the sheath. Reducing and increasing the load tolerance at the blade tip after the blade is applied to the tissue. That is, the system can remain locked to the resonant frequency of the blade during use in the presence of a larger load. In addition, the tolerance of tissue loading and the avoidance of unlocking by “gunk” are greatly improved, allowing the user to handle and operate relatively easily during operation of the ultrasonic surgical blade system. Can be done. In addition, secondary resonances can be placed near the center frequency of the blade or near the ideal resonant frequency without the traditional risk of locking the generator to secondary resonances, Blade design can be simplified. In addition, since the primary resonant frequency of the blade can be arranged further away from the center frequency, it can also be recognized by a progressively expanding search for the resonant frequency.
These and other features and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments of the invention based on the accompanying drawings.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a system for carrying out the method according to the invention. A set of wires in the cable 20 sends electrical energy, i.e., drive current, from the console 10 to the hand piece 30 where the electrical energy is transferred to a surgical device such as a surgical scalpel blade 32. Is subjected to ultrasonic vibration along the longitudinal direction. The blade 32 can be used for simultaneous tissue dissection and cauterization. The ultrasonic current can be supplied to the hand piece 30 under the control of a switch 34 disposed on the hand piece 30, which switch 34 is connected to the inside of the console 10 via a wire in the cable 20. Connected to generator. Furthermore, the generator 10 can be controlled by a foot switch 40, which is connected to the console 10 via another cable 50. Thus, in use, the surgeon operates the switch 34 on the hand piece with his / her finger or operates the foot switch 40 with his / her foot to provide an ultrasonic electrical signal to the hand piece. Thus, the blade can be vibrated along the longitudinal direction at a constant ultrasonic frequency.
[0024]
The generator console 10 includes a liquid crystal display 12, which indicates a cutting power level selected in various means such as a maximum cutting power rate or a numerical power level associated with the cutting power. Can be used for The liquid crystal display device 12 can also be used to display other parameters in the system. The output switch 11 is used to start the device. In the warm-up state, the “standby” light 13 is lit. When ready for operation, the “ready” indicator 14 is lit and the standby light is extinguished. When the device supplies maximum output, the MAX button 15 is pressed. If less output is required, the MIN button 17 is activated. Further, the output level when the MIN button 17 is operated is set by the button 16.
[0025]
When output is supplied to the ultrasonic hand piece by the operation of either switch 34 or switch 40, the assembly causes the surgical scalpel or blade to vibrate along the length of about 55.5 kHz. The amount of movement in the direction changes in proportion to the amount of drive output (current) selected to be adjustable by the user. The blade is designed to move longitudinally in the range of about 40 microns to 100 microns at its ultrasonic vibration speed when a relatively high cutting power is provided. Heat is generated when the blade contacts the tissue due to the ultrasonic vibration of the blade. That is, as the blade accelerates in the tissue, the mechanical energy of the moving blade is converted into thermal energy within a very narrow localized region. This localized heat forms a narrow region of coagulation, which can reduce or eliminate bleeding in blood vessels smaller than 1 millimeter in diameter. The cutting efficiency and the degree of hemostasis of this blade will vary depending on the level of drive power delivered, the surgeon's cutting speed, the nature of the tissue and the vessel distribution.
[0026]
As shown in more detail in FIG. 2, the ultrasonic hand piece 30 houses a piezoelectric transducer 36 for converting electrical energy into mechanical energy to produce a vibrating motion along the longitudinal direction at each end of the transducer. is doing. The transducer 36 is in the form of a stacked ceramic piezoelectric element having a motion null point located at a specific point along the stack. This transducer stack is mounted between two cylinders 31 and 33. Further, a cylinder 35 is attached to the cylinder 33, and the cylinder 35 is attached to the inside of the housing at another operation zero point 37. Further, the horn 38 is attached to the zero point 37 on one end side thereof, and is attached to the coupler 39 on the other end side. The blade 32 is fixed to the coupler 39. As a result, the blade 32 vibrates along the longitudinal direction at a constant ultrasonic frequency by the transducer 36. Each end of the transducer performs maximum operation with the portion of the stack that forms the stationary node when driven by a constant maximum current at the resonant frequency of the transducer. However, the current for this maximum operation varies with each hand piece and is a valve stored in the hand piece's non-volatile memory that the system can use.
[0027]
Each part of the hand piece is designed so that its combination vibrates at the same resonant frequency. In particular, each element is tuned so that the final length of each of these elements is ½ wavelength. The longitudinal movement along the longitudinal direction is amplified as the diameter of the acoustic mounting horn 38 closer to the blade 32 decreases. Accordingly, the horn 38 and the blade / coupler are shaped and dimensioned to amplify the blade motion and provide a tuned resonant vibration for the rest of the acoustic system, thereby providing proximity to the blade 32. Maximum back-and-forth motion occurs at the end of the acoustic mounting horn 38. Operation in the transducer stack is amplified by the horn 38 and travels from about 20 microns to 25 microns. In addition, movement in the coupler 39 is amplified by the blade 32 and the blade moves from about 40 microns to 100 microns.
[0028]
A system for generating an ultrasonic electrical signal for driving a transducer in the hand piece is shown in FIGS. This drive system is flexible and can generate drive signals at the desired frequency and output level setpoints. The DSP 60 or microprocessor in the system is used to monitor the appropriate output parameters and vibration frequency to produce the appropriate output level that is supplied in either the cutting or coagulation mode of operation. The DSP 60 or microprocessor also stores a computer program that is used to perform diagnostic tests on components in the system such as transducers / blades.
[0029]
For example, under the control of a program such as a phase correction algorithm stored in the DSP or the microcomputer 60, the starting frequency can be set to a specific value, for example, 50 kHz. This can be done by sweeping at a specific rate until a change in impedance indicating close to resonance is detected. Thereafter, the sweep rate is decreased so that the system does not overshoot the resonant frequency, eg, 55 kHz. This sweep rate can be achieved, for example, by obtaining a frequency change in increments of 50 cycles. If a relatively slow speed is desired, the program can reduce the increase to, for example, 25 cycles, and both cases can be adapted based on the measured magnitude and phase of the impedance. Of course, a greater speed can be achieved by increasing the magnitude of the increase. Further, the sweep speed can be changed by changing the update speed corresponding to the increase in the frequency.
[0030]
For example, if it is known that an undesired resonance mode exists at 51 kHz, the program can find the resonance by sweeping the frequency down, for example, from 60 kHz. Furthermore, the system can sweep from 50 kHz and jump over 51 kHz where unwanted resonance exists. In either case, the system has a high degree of flexibility.
[0031]
In operation, the user sets a specific power level for use in the surgical device. This process is performed by the output level switch 16 on the front panel of the console. This switch generates a signal 150 that is supplied to the DSP 60. After that, the DSP 60 displays a predetermined output level by sending a signal on the wiring 152 (FIG. 4) to the display device 12 of the console front panel. In addition, the DSP or microprocessor 60 generates a digital current level signal 148 that is converted to an analog signal by a digital-to-analog converter (DAC) 130. The obtained reference analog signal is supplied to the summing node 132 as a current set point. A signal indicating the average output current from circuit 120 is provided to the negative input of node 132. The output of node 132 is a current error signal or amplitude control signal that is fed directly to a digital synthesis (DDS) circuit 128 to adjust the amplitude of that output, and the frequency at that output is wired from the DSP or microprocessor 60. Controlled by the signal on 146. Adjustment of the signal provided by the current level signal 148, DAC 130, summing node 132, and average output voltage 122 allows adjustment of the output current by the DSP or microprocessor 60, as desired when not in a steady current mode. Output vs. load curve can be created.
[0032]
In order to actually vibrate the surgical blade, the user activates the foot switch 40 or the hand piece switch 34. By this operation, a signal is sent on the wiring 154 in FIG. This signal is useful for providing an output from push-pull amplifier 78 to transducer 36. When the DSP or microprocessor 60 locks the handpiece transducer's resonant frequency and the output is continuously supplied to the handpiece transducer, an audio drive signal is sent on line 156. This causes the sound indicating means in the system to generate a sound, notifying the user that the output is supplied to the hand piece and that the scalpel is in operation.
[0033]
Under the control of a program stored in a DSP or microprocessor in the system shown in FIGS. 3 and 4, the method of the present invention causes the transducer 36 to operate at a relatively high voltage level, such as 140 volts, or a relatively high current level. Implemented by sweeping to deal with loads on the blade 32 that are present at start-up, eg, on the blade, such as “drag” and inertial effects, to cause a recognizable and lockable resonant action. Trigger enough motion. A heavily loaded blade forms a highly damped system, where the impedance of the transducer is relatively high. The higher the voltage, the more current can flow through its relatively high impedance, resulting in a suitable current that can be easily measured. A DSP 60 or microprocessor is used to monitor the appropriate parameter, which in this case is the resonant frequency of the transducer, and this value is indicated by the magnitude of the maximum phase or minimum impedance of the frequency.
[0034]
FIG. 5 is a flow chart illustrating a preferred embodiment of the method of the present invention. In step 400, a drive signal is first supplied to the hand piece / blade. Next, at step 410, a frequency sweep is performed to locate the handpiece / blade resonant frequency. In addition, as shown at step 420, a test is performed to determine whether the DSP or microprocessor 60 is locking. If the lock is done, the method ends. If the DSP or microprocessor 60 is not locking, at step 430, the drive frequency level is increased and step 410 is repeated. Thus, the method continues in a “loop” until the DSP or microprocessor 60 locks.
[0035]
In another embodiment of the present invention, starting in a loaded condition with a progressively higher current / voltage during each sweep process until the blade 36 is locked onto the resonant frequency is performed. As a result, it is avoided that the blade 36 is driven by a signal that is too large to cause an overshoot due to an accidental displacement of the blade due to the limitation of the feedback control circuit. Resonance in the intended operation of the blade can be recognized by measuring the resonant impedance during the sweep. Therefore, if the blade resonance cannot be positioned after sweeping over the frequency range involved by a particular drive current, an attempt to detect this resonance is made at a higher current level. Furthermore, these steps are repeated at continuously elevated drive levels until blade resonance is obtained. Alternatively, the maximum phase or minimum magnitude of the impedance within the specific frequency range can be detected, and resonance is detected by increasing the drive current at this frequency. In positioning the resonant frequency, the current drive signal is reduced as necessary to the required operating level. In this way, a quicker and more accurate recognition of the actual operational resonance of the blade and avoidance of accidental confusion with other resonances can be achieved.
[0036]
FIG. 6 is a flow chart illustrating another embodiment of the method of the present invention. In this case, rather than starting a sweep at a low drive current level, a moderate to strong drive signal is supplied to the blade. As shown in step 500, such a drive signal is first supplied to the hand piece / blade. Next, in step 510, a frequency sweep is performed to position the handpiece / blade resonant frequency. Thereafter, in step 520, a test is performed to determine if there are multiple resonances in the hand piece / blade. Further, in step 540, if there are multiple resonances, the level of the drive signal is lowered and returned to step 510. If there are not many resonances in the hand piece / blade, a test is performed to determine if the DSP or microprocessor 60 is locking, as shown in step 530. If the lock is done, the method ends. If the DSP or microprocessor 60 is not locked, the drive signal level is increased in step 540 and step 510 is repeated. In this manner, the above method continues in a “looping” until one primary resonance is found and the DSP or microprocessor 60 can lock. The sweeping process in this manner can substantially reduce the processing time. Another advantage of starting the sweep process at a higher drive level is the ability to obtain a more robust resonant frequency in a highly damped blade, which allows for faster resonance recognition and locking. .
[0037]
FIG. 7 is a flow chart illustrating another embodiment of the method of the present invention. In this case, a sweeping process that spreads progressively is performed, and a driving signal having an intensity that gradually increases and tilts upward is used to drive the blade. Such a combination can provide the advantages of both a time-saving narrow sweep range and a high power that can reliably resonate the blade. In step 600, a drive signal is provided to the hand-piece / blade. As shown in step 610, a narrow frequency sweep is performed to position the handpiece / blade resonant frequency. Next, as shown in step 620, a test is performed to determine whether the DSP or microprocessor 60 is locking. If the lock is done, the method ends. If there is no lock, a test is performed to determine if there are multiple resonances in the hand piece / blade, as shown in step 630. If there are not many resonances in the hand piece / blade, the input signal is reduced at step 640 and the method proceeds to step 650. If there are multiple resonances in the hand piece / blade, the method proceeds directly to step 650 and proceeds to step 610 after the frequency sweep range is narrowed in the step. In this way, the method continues “looping” until the DSP or microprocessor 60 locks. This embodiment according to the invention facilitates the rapid recognition of the desired resonance of the damped blade without accidentally driving the blade in an unwanted resonance.
[0038]
FIG. 8 is a flow chart showing yet another embodiment of the method of the present invention. In an embodiment of the invention, the resonance sweep process begins with the most central position or ideal oscillation in the blade. As shown in step 700, a constant drive frequency is first supplied to the hand piece / blade. Next, at step 710, the resonance frequency of the hand piece / blade is positioned by performing a frequency sweep, starting with the ideal or central resonance frequency of the hand piece / blade. In addition, in step 720, a test is performed to determine whether the DSP or microprocessor 60 has already locked. If the lock is done, the method ends. If there is no lock, then in step 730, a sweep is performed approximately in the vicinity of the handpiece / blade resonant frequency. Thereafter, as shown in step 740, the test is again performed to determine if the DSP or microprocessor 60 has already locked. If the lock is done, the method ends.
[0039]
In step 750, if the lock is not performed, a sweep is performed in the outward direction (that is, the frequency range is expanded) from the previous sweep frequency. Further, at step 760, the test is performed again to determine whether the DSP or microprocessor 60 is locking. If the lock is done, the method ends. If no lock has been made, return to step 750. This method continues "looping" in this manner until the DSP or microprocessor 60 locks. To save time, each progressively expanding frequency sweep skips already processed frequencies and concentrates only on unexamined frequencies within the expanded range to be re-inspected. Thus, the recognition of the resonant frequency can be accelerated because most blades have a primary resonant frequency that is relatively close to the hand piece / blade center or ideal frequency.
[0040]
By the method of the present invention, an accelerated resonance frequency can be swept. This is partly due to the fact that a more robust electrical response of the transducer / acoustic system is obtained when driven by a relatively large voltage / current, resulting in a more clarified transducer response. Further, the signal track can be easily performed, and the resonance frequency can be easily locked.
[0041]
While the invention has been illustrated and described in detail above, it should be understood that these are for purposes of illustration and are not intended to be limiting. The scope and spirit of the invention is limited only by the terms of the claims and the embodiments described herein.
[0042]
  Embodiments of the present invention are as follows.
  (A) In a method for driving an ultrasound system to improve blade resonance capture at start-up,
Supplying a drive signal to an ultrasonic hand piece / blade by an ultrasonic generator;
Performing a frequency sweep to position the resonant frequency of the blade;
Determining whether a microprocessor located in the generator has already captured the resonant frequency of the blade;
If the microprocessor is not capturing the blade's resonant frequency, the method includes increasing the drive signal level and continuously performing a frequency sweep until the microprocessor captures the blade's resonant frequency.
  (1) The step of supplying the driving signal includes exciting the hand piece / blade with an ultrasonic signal at a predetermined driving frequency.Embodiment (A)The method described in 1.
  (2) The method of embodiment (1), wherein the drive signal has a voltage level of about 140 volts.
  (3) Start in a loaded state at a driving current / voltage level that progressively increases during each sweep process until the blade is locked to the resonant frequency.Embodiment (A)The method described in 1.
(B) In a method for driving an ultrasound system to improve handpiece / blade resonance capture at start-up,
Supplying a medium to strong drive signal to an ultrasonic hand piece / blade by an ultrasonic generator;
Performing a frequency sweep to position the handpiece / blade resonant frequency;
Determining whether multiple resonant frequencies are present in the hand piece / blade;
Continuously reducing the drive frequency level and performing a frequency sweep when multiple resonances are present in the hand piece / blade;
To determine if the microprocessor located in the generator has already captured the resonant frequency of the hand piece / blade when multiple resonances are not present in the hand piece / blade A process of inspecting,
If the microprocessor is not capturing the handpiece / blade resonant frequency, increasing the drive signal level and continuing the frequency sweep until the microprocessor captures the blade resonant frequency. Including methods.
(C) In a method for driving an ultrasound system to improve handpiece / blade resonance capture at start-up,
Supplying a drive signal to an ultrasonic hand piece / blade by an ultrasonic generator;
Performing a narrow frequency sweep to position the handpiece / blade resonant frequency;
Determining whether a microprocessor located in the generator has already captured the resonant frequency of the blade;
Determining whether multiple resonant frequencies are present in the hand piece / blade if the microprocessor is not capturing the resonant frequency of the hand piece / blade;
Increasing the drive signal level to increase the sweep frequency when multiple resonances are not present in the hand piece / blade;
Reducing the frequency sweep range when multiple resonances are present in the hand piece / blade;
Returning to the step of positioning the resonant frequency of the hand piece / blade by performing a narrow frequency sweep.
(D) Supersonics to improve handpiece / blade resonance capture at start-up In a method for driving a wave system,
Supplying a drive signal to an ultrasonic hand piece / blade by an ultrasonic generator;
Performing a frequency sweep from the ideal frequency at the hand piece / blade to position the resonant frequency of the hand piece / blade;
Determining whether a microprocessor located in the generator has already captured the resonant frequency of the blade;
If the microprocessor is not capturing the resonant frequency of the hand piece / blade, sweeping approximately in the vicinity of the ideal frequency at the hand piece / blade
Determining whether the microprocessor has already captured the resonant frequency of the blade;
Performing a frequency sweep in an outward direction from a previous sweep frequency if the microprocessor has not captured the resonant frequency of the hand piece / blade;
Determining whether the microprocessor has already captured the resonant frequency of the blade;
Returning to the step of performing a frequency sweep outward from the previous sweep frequency if the microprocessor has not captured the resonant frequency of the hand piece / blade.
  (4) The ideal frequency is about 55 kHz.Embodiment (D)The method described in 1.
  (5) The method according to embodiment (4), wherein the step of sweeping the frequency outward from the previous sweep frequency includes increasing a certain frequency range.
[0043]
【The invention's effect】
Thus, the present invention provides a method for driving an ultrasound system to improve handpiece / blade resonance capture at start-up.
[Brief description of the drawings]
FIG. 1 is a perspective view of a console and hand piece and foot switch for an ultrasonic surgical cutting and hemostasis system for carrying out the method of the present invention.
2 is a schematic cut-away view of an ultrasonic surgical scalpel hand piece of the ultrasonic surgical cutting and hemostasis system of FIG. 1; FIG.
3 is a block diagram illustrating a system for driving a transducer in the hand piece of the ultrasonic surgical cutting and hemostasis system of FIG. 1. FIG.
4 is a block diagram illustrating a system for driving a transducer in the hand piece of the ultrasonic surgical cutting and hemostasis system of FIG. 1; FIG.
FIG. 5 is a flow chart of a preferred embodiment of the method of the present invention.
FIG. 6 is a flow chart of another embodiment of the method of FIG.
FIG. 7 is a flow chart of another embodiment of the method of FIG.
FIG. 8 is a flow chart of another embodiment of the method of FIG.
[Explanation of symbols]
10 Console
20 cables
30 hand piece
32 Blade for surgical knife
40 foot switch
50 cables

Claims (9)

In a method for driving an ultrasound system to improve blade resonance capture at start-up,
Supplying a drive signal to an ultrasonic hand piece / blade by an ultrasonic generator;
Performing a frequency sweep to determine the resonant frequency of the blade;
Determining whether a microprocessor located in the generator has already captured the resonant frequency of the blade;
When the microprocessor captures the resonance frequency of the blade, the driving signal level is adjusted to a value required for the operation level on the resonance frequency; and
If the microprocessor is not capturing the blade's resonant frequency, the method includes increasing the drive signal level and continuously performing a frequency sweep until the microprocessor captures the blade's resonant frequency. The method of claim 1, wherein providing the drive signal comprises exciting the hand piece / blade with an ultrasonic signal at a predetermined drive frequency. The method of claim 2, wherein the drive signal has a voltage level of about 140 volts. 2. A method according to claim 1, wherein starting is performed under load at a driving current / voltage level that progressively increases during each sweeping process until the resonance frequency of the blade is locked. In a method for driving an ultrasound system to improve handpiece / blade resonance capture at start-up,
Supplying a medium to strong drive signal to an ultrasonic hand piece / blade by an ultrasonic generator;
Performing a frequency sweep to determine the handpiece / blade resonant frequency;
Determining whether multiple resonant frequencies are present in the hand piece / blade;
Continuously reducing the drive frequency level and performing a frequency sweep when multiple resonances are present in the hand piece / blade;
For determining whether a microprocessor located in the generator is not capturing the resonance frequency of the hand piece / blade when multiple resonances are not present in the hand piece / blade An inspection process;
If the microprocessor is not capturing the handpiece / blade resonant frequency, increasing the drive signal level and continuing the frequency sweep until the microprocessor captures the blade resonant frequency. Including methods. In a method for driving an ultrasound system to improve handpiece / blade resonance capture at start-up,
Supplying a drive signal to an ultrasonic hand piece / blade by an ultrasonic generator;
Performing a narrow frequency sweep to determine the handpiece / blade resonant frequency;
Determining whether a microprocessor located in the generator has already captured the resonant frequency of the blade;
Determining whether multiple resonant frequencies are present in the hand piece / blade if the microprocessor is not capturing the resonant frequency of the hand piece / blade;
Increasing the drive signal level to increase the sweep frequency when multiple resonances are not present in the hand piece / blade;
Reducing the frequency sweep range when multiple resonances are present in the hand piece / blade;
Returning to the step of determining the resonant frequency of the hand piece / blade by performing a narrow frequency sweep. In a method for driving an ultrasound system to improve handpiece / blade resonance capture at start-up,
Supplying a drive signal to an ultrasonic hand piece / blade by an ultrasonic generator;
Performing a frequency sweep from an ideal frequency in the hand piece / blade to determine a resonance frequency of the hand piece / blade;
Determining whether a microprocessor located in the generator has already captured the resonant frequency of the blade;
If the microprocessor is not capturing the resonant frequency of the hand piece / blade, sweeping approximately in the vicinity of the ideal frequency at the hand piece / blade;
Determining whether the microprocessor has already captured the resonant frequency of the blade;
Performing a frequency sweep in an outward direction from a previous sweep frequency if the microprocessor has not captured the resonant frequency of the hand piece / blade;
Determining whether the microprocessor has already captured the resonant frequency of the blade;
Returning to the step of performing a frequency sweep outward from the previous sweep frequency if the microprocessor has not captured the resonant frequency of the hand piece / blade. The method of claim 7, wherein the ideal frequency is about 55 kHz. 9. The method of claim 8, wherein performing a frequency sweep outward from the previous sweep frequency includes increasing a constant frequency range.

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