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Devices and techniques for cutting and coagulating tissue

  • US 9,700,343 B2
  • Filed: 11/02/2015
  • Issued: 07/11/2017
  • Est. Priority Date: 04/09/2012
  • Status: Active Grant
First Claim
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1. A method of driving an end effector coupled to an ultrasonic drive system of a surgical instrument, the method comprising:

  • providing, by a generator configured to drive the surgical instrument, a first electrical signal to an ultrasonic transducer acoustically coupled to the end effector;

    detecting, by the generator, that an impedance of the ultrasonic transducer exceeds a threshold impedance;

    storing, by the generator, a first local resonant frequency of the first electrical signal as a baseline resonant frequency;

    monitoring, by the generator, the first electrical signal against a first set of logic conditions comprising a first logic condition and a second logic condition, wherein the first logic condition is defined by a difference between a second local resonant frequency of the first electrical signal and the baseline resonant frequency that is greater than a baseline deviation threshold;

    determining, by the generator, that the first logic condition is met; and

    triggering, by the generator, a first response.

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