Ultrasonic device for cutting and coagulating with stepped output
View Patent ↗An apparatus, system, and method for driving an end effector in a surgical instrument are disclosed. The method comprises generating a first ultrasonic drive signal by a generator, actuating the ultrasonic transducer with the first ultrasonic drive signal for a first period, generating a second ultrasonic drive signal by the generator, and actuating the ultrasonic transducer with the second ultrasonic drive signal for a second period, subsequent to the first period. The first drive signal second drive signal are different over the first and second periods. The first and second drive signals define a step function waveform over the first and second periods. The apparatus comprises a generator to couple to an ultrasonic instrument. The system comprises a generator coupled to an ultrasonic instrument comprising an ultrasonic drive system comprising an ultrasonic transducer coupled to a waveguide and an end effector. The ultrasonic drive system resonates at a resonate frequency.
1. An apparatus for driving an end effector coupled to an ultrasonic drive system of a surgical instrument, the method comprising:
a generator configured to couple to an ultrasonic drive system of an ultrasonic instrument, the ultrasonic drive system comprising an ultrasonic transducer coupled to a waveguide and an end effector coupled to the waveguide;
wherein the generator is configured to:
generate a first ultrasonic drive signal;
actuate the ultrasonic transducer with the first ultrasonic drive signal for a first period;
generate a second ultrasonic drive signal by the generator; and
actuate the ultrasonic transducer with the second ultrasonic drive signal for a second period, subsequent to the first period;
wherein the first drive signal is different from the second drive signal over the respective first and second periods; and
wherein the first and second drive signals define a step function waveform over the first and second periods.
2. The apparatus of claim 1 , comprising a measurement module to monitor a measurable characteristic of the ultrasonic drive system, wherein the generator is configured to generate any one of the first and second drive signals based on a measured characteristic.
3. The apparatus of claim 2 , wherein the measurement module comprises:
a radio frequency (RF) generator coupled to the end effector, the radio frequency generator configured to generate a subtherapeutic RF signal; and
a clamp arm assembly coupled to a distal end of the ultrasonic drive system, the clamp arm assembly comprising an electrically conductive portion forming a return electrode coupled to the RF generator, the clamp arm assembly being operatively coupled to the end effector to grasp tissue therebetween.
4. The apparatus of claim 2 wherein the measurement module comprises:
a voltage sense module;
a current sense module;
an analog-to-digital converter (ADC) coupled to the voltage sense module and the current sense module; and
a processor coupled to the ADC, the processor being configured to measure impedance.