According to some embodiments, a medical instrument comprises an elongate body having a proximal end and a distal end and a pair of electrodes or electrode portions (for example, a split-tip electrode assembly). Systems and methods are described herein that perform contact sensing and/or ablation confirmation based on electrical measurements obtained while energy of different frequencies are applied to the pair of electrodes or electrode portions. The contact sensing systems and methods may calibrate network parameter measurements to compensate for a hardware unit in a network parameter measurement circuit or to account for differences in cables, instrumentation or hardware used.

A system includes a signal generator, configured to pass a generated signal, which has two different generated frequencies, through a circuit including an intrabody electrode. The system further includes a processor, configured to identify, while the generated signal is passed through the circuit, a derived frequency, which is derived from the generated frequencies, on the circuit, and to generate, in response to identifying the derived frequency, an output indicating a flaw in the electrode. Other embodiments are also described.

Various embodiments provide an electrosurgical instrument for delivering electromagnetic (EM) energy and ultrasonic vibrations for treating biological tissue. The electrosurgical instrument comprises: an instrument shaft arranged to convey EM energy and an electrical signal for driving a magnetostrictive ultrasound transducer; a distal end assembly arranged at a distal end of the instrument shaft to receive the EM energy from the instrument shaft and deliver the EM energy from the distal end assembly for tissue treatment; and a magnetostrictive ultrasound transducer arranged to receive the electrical signal from the instrument shaft and generate ultrasonic vibrations around the distal end assembly for tissue treatment. Other embodiments provide an electrosurgical generator, and an electrosurgical apparatus comprising the instrument and generator.

An ultrasonic device may include an electromechanical ultrasonic system defined by a predetermined resonant frequency, in which the system may include an ultrasonic transducer coupled to an ultrasonic blade. A method of estimating a state of an end effector of the ultrasonic device may include applying a drive signal defined by a magnitude and a frequency to the ultrasonic transducer, sweeping the frequency of the drive signal from below a first resonance to above the first resonance of the electromagnetic ultrasonic system, measuring and recording, impedance/admittance circle variables R.sub.e, G.sub.e, X.sub.e, and B.sub.e, comparing, the measured impedance/admittance circle variables R.sub.e, G.sub.e, X.sub.e, and B.sub.e to reference impedance/admittance circle variables R.sub.ref, G.sub.ref, X.sub.ref, and B.sub.ref, and determining, a state or condition of the end effector based on the result of the comparison. An electromechanical ultrasonic system may include a control circuit to effect the method.

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.

An electrosurgical generator having an oscillating circuit that is excited by an excitation circuit with a frequency preferably close to the resonance frequency of the oscillating circuit. A regeneration circuit, which may be a voltage multiplier circuit, is used to stop the oscillation as suddenly as possible without losing the energy stored in the oscillating circuit.

Provided is a method for managing radio frequency (RF) and ultrasonic signals output by a generator that includes a surgical instrument comprising an RF energy output and an ultrasonic energy output and a circuit configured to receive a combined RF and ultrasonic signal from the generator. The method includes receiving a combined radio frequency (RF) and ultrasonic signal from a generator, generating a RF filtered signal by filtering RF frequency content from the combined signal; filtering ultrasonic frequency content from the combined signal; generating an ultrasonic filtered signal; providing the RF filtered signal to the RF energy output; and providing the ultrasonic filtered signal to the ultrasonic energy output.

Tumors can be treated with an alternating electric field. The size of cells in the tumor is determined prior to the start of treatment by, for example, biopsy or by inverse electric impedance tomography. A treatment frequency is chosen based on the determined cell size. The cell size can be determined during the course of treatment and the treatment frequency is adjusted to reflect changes in the cell size. A suitable apparatus for this purpose includes a device for measuring the tumor impedance, an AC signal generator with a controllable output frequency, a processor for estimating the size of tumor cells and setting the frequency of the AC signal generator based thereon, and at least one pair of electrodes operatively connected to the AC signal generator such that an alternating electric field is applied to the tumor.

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.

According to some embodiments, a medical instrument (for example, an ablation device) comprises an elongate body having a proximal end and a distal end, an energy delivery member positioned at the distal end of the elongate body, a first plurality of temperature-measurement devices carried by or positioned within the energy delivery member, the first plurality of temperature-measurement devices being thermally insulated from the energy delivery member, and a second plurality of temperature-measurement devices positioned proximal to a proximal end of the energy delivery member, the second plurality of temperature-measurement devices being thermally insulated from the energy delivery member.