A method of ultrasonic sealing includes activating an ultrasonic blade temperature sensing, measuring a first resonant frequency of an ultrasonic electromechanical system that includes a transducer coupled to the blade via a waveguide, making a first comparison between the measured first resonant frequency and a first predetermined resonant frequency, and adjusting a power level applied to the transducer based on the first comparison. The first predetermined frequency may correspond to an optimal tissue coagulation temperature. The method may further include measuring a second resonant frequency of the system, making a second comparison between the measured second frequency and a second predetermined frequency, and adjusting the power level based on the second comparison. The second predetermined frequency may correspond a melting point temperature of a clamp arm pad. An ultrasonic instrument and a generator may implement the method.

A method of determining an initial temperature of an ultrasonic blade may include measuring a resonant frequency of an ultrasonic blade prior to activating an ultrasonic transducer, in which the ultrasonic transducer is coupled to the blade via an ultrasonic waveguide, comparing the measured resonant frequency to a baseline resonant frequency, determining an initial temperature of the ultrasonic blade based on a difference between the measured resonant frequency and the baseline resonant frequency, and applying a power level to the blade based on the initial temperature of the blade. The method may further include applying a high power level to the transducer when the initial temperature of the ultrasonic blade is low or applying a low power level to the transducer when the initial temperature of the blade is high. The baseline resonant frequency may be stored in a memory look up table.

A radio frequency (RF) instrument may include a method of classifying a tissue in live time. The method may include activating the instrument for a first period of time T1 when the RF instrument contacts the tissue, plotting at least three electrical parameters associated with the tissue to classify the tissue into distinct groups, and applying a classification algorithm to classify the tissue into a distinct group in live time. The parameters may include an initial impedance of the tissue, a minimum impedance of the tissue, and an amount of time that the impedance slope is ?0. The instrument may collect the parameters during a predetermined amount of time, such as within the first 0.75 seconds of the activation of the device. The classification algorithm may include a support vector machine algorithm that may use a linear, polynomial, or radial basis set.

A method of controlling the application of energy to a radio frequency (RF) instrument based on a surgical technique may include activating the instrument for a first period T1, during which time a portion of an end effector contacts a tissue, plotting at least two electrical parameters associated with the tissue to classify an amount of the end effector in contact with the tissue, applying a classification algorithm to classify the amount of the end effector in contact with the tissue, and applying an amount of energy to the end effector based on the amount of the end effector in contact with the tissue. The parameters may include a minimum impedance of the tissue and an amount of time that the impedance slope is ?0. The end effector may contact the tissue with a tip end or with an entire surface.

A generator, ultrasonic device, and method for controlling a temperature of an ultrasonic blade are disclosed. A control circuit coupled to a memory determines an actual resonant frequency of an ultrasonic electromechanical system comprising an ultrasonic transducer coupled to an ultrasonic blade by an ultrasonic waveguide. The actual resonant frequency is correlated to an actual temperature of the ultrasonic blade. The control circuit retrieves from the memory a reference resonant frequency of the ultrasonic electromechanical system. The reference resonant frequency is correlated to a reference temperature of the ultrasonic blade. The control circuit then infers the temperature of the ultrasonic blade based on the difference between the actual resonant frequency and the reference resonant frequency. The control circuit controls the temperature of the ultrasonic blade based on the inferred temperature

Surgical instruments with ultrasonic cutting and sensing capabilities, as well as related systems and methods, are disclosed herein. In one aspect, the present disclosure provides a surgical instrument including a housing; an ultrasonic transducer contained in the housing and capable of acting as an ultrasonic receiver; an output member at least partially received in the housing and configured to be driven by the ultrasonic transducer; a dissection head having an attachment portion configured to be selectively driven by the ultrasonic transducer; and a controller operable to initiate and stop the ultrasonic transducer according to an alternating duty cycle.

A medical device system that includes an ultrasound transducer and a processor. The ultrasound transducer includes a plurality of electrode plates to which a drive signal is supplied, and a plurality of piezoelectric elements that are alternately arranged with the electrode plates, and that generate ultrasound vibrations according to the drive signal. The ultrasound transducer also includes an electric wiring that electrically connects the electrode plates adjacent to each other, and a memory that stores reference information regarding specific initial characteristics. The processor analyzes the generated ultrasonic vibrations to determine a resonance point of the ultrasound transducer, and detects resonance point information regarding the resonance point. The processor then determines whether an abnormality has occurred in the ultrasound transducer by comparing the stored reference information and the detected resonance point information.

A system for removing occlusive clot from a blood vessel comprises a catheter and an apparatus for generating a pulsatile vacuum force to pulse the pressure gradient at a distal end of the catheter. The pulse generator may be integral with or separate from the vacuum pump. The pulse generator may be applied to a flexible tubing between the vacuum pump and the proximal end of the catheter.

Methods, computing devices, and a computer-readable medium are described herein related to fragmenting or comminuting an object in a subject using a burst wave lithotripsy (BWL) waveform. A computing device, such a computing device coupled to a transducer, may carry out functions for producing a BWL waveform. The computing device may determine a burst frequency for a number of bursts in the BWL waveform, where the number of bursts includes a number of cycles. Further, the computing device may determine a cycle frequency for the number of cycles. Yet further, the computing device may determine a pressure amplitude for the BWL waveform, where the pressure amplitude is less than or equal to 8 MPa. In addition, the computing device may determine a time period for producing the BWL waveform.

A piezoelectric device comprising: (a) a handpiece for holding by a user; (b) a cutting insert for said handpiece; (c) an ultrasound transducer disposed within the handpiece, the ultrasound transducer capable of providing first and second ultrasound frequency vibrations to the cutting insert in response to an electrical signal; and (d) a switch allowing the user to control the electrical signal and thereby provide either said first or second ultrasound frequency vibrations to the cutting insert.
The device is useful in a method of placing an implant into an implant site comprising cutting overlying gingival tissue at a first ultrasound frequency capable of cutting soft tissue, then switching to a second ultrasound frequency capable of cutting the underlying jawbone.