A control circuit of a surgical device is disclosed. The control circuit includes a first circuit portion coupled to at least one switch operable between an open state and a closed state. The first circuit portion communicates with a surgical generator over a conductor pair to receive a control signal to determine a state of the at least one switch.

Surgical generator for ultrasonic and electrosurgical devices

A surgical instrument. The surgical instrument may comprise a transducer and an end effector. The transducer may be configured to provide vibrations along a longitudinal axis at a predetermined frequency and may comprise a piezoelectric stack positioned along the longitudinal axis. The transducer also may comprise a first metallic end mass positioned along the longitudinal axis adjacent a first end of the piezoelectric stack and a second metallic end mass positioned along the longitudinal axis adjacent a second end of the piezoelectric stack. The length of the transducer may be greater than or equal to of one wavelength and less than ½ of one wavelength. The end effector may be coupled to the transducer and may extend along the longitudinal axis. The length of the transducer and the end effector may be a multiple of ½ of one wavelength.

Ultrasonic surgical instruments

A surgical instrument for supplying energy to tissue may comprise a handle, a trigger, an electrical input, and a shaft extending from the handle. The surgical instrument may comprise and end effector first and second tissue engaging surfaces that are slanted with respect to a transection plane. The end effector may, for example, have an electrode defining a V-shaped cross sectional profile. The end effector may comprise a plurality of raised surfaces that are received by a plurality of indentions when the end effector is in the closed position. The end effector may comprise a cutting member having a plurality of bands. A surgical instrument for supplying energy to tissue may comprise a handle, a trigger, an electrical input, and a shaft extending from the handle. The surgical instrument may comprise an end effector. The end effector may comprise a cammed compression surface. The end effector may comprise an electrode comprising a tapered tissue contacting surface. Some surgical instruments may comprise an overload member.

Surgical instrument with jaw member

Various embodiments described herein are directed to ultrasonic blades. For example, an ultrasonic blade may comprise a proximally positioned straight section extending along a longitudinal axis and a distally positioned curved section coupled to the straight section and curved away from the longitudinal axis. The curved section may define a radius of curvature and subtend a first angle. A point of tangency between the curved section and the straight section may be positioned at either a node of the ultrasonic blade or an anti-node of the ultrasonic blade.

Surgical instruments with articulating shafts

Various embodiments are direct to a surgical instrument comprising and end effector, an articulating shaft and an ultrasonic transducer assembly. The end effector may comprise an ultrasonic blade. The articulating shaft may extend proximally from the end effector along a longitudinal axis and may comprise a proximal shaft member and a distal shaft member pivotably coupled at an articulation joint. The ultrasonic transducer assembly may comprise an ultrasonic transducer acoustically coupled to the ultrasonic blade. The ultrasonic transducer assembly may be positioned distally from the articulation joint.

Ultrasonic surgical instruments with distally positioned transducers

A method of controlling electrosurgical power delivery based on a comparison of sensed tissue impedance to various impedance threshold values is provided. Energy is delivered to tissue in a sealing cycle as a series of pulses. An initial pulse has a profile with a preset energy starting value that increases at a ramping rate to a preset end value. Sensed impedance data are monitored throughout each pulse and compared to each of an impedance threshold value for RF setpoint, an impedance threshold value for cumulative time, and an impedance threshold value for energy cutback. Based on sensed impedance during a pulse, the profile of a subsequent pulse can be modified. In the event of a high impedance event that reflects low tissue presence, energy may be cutback. A sealing cycle is stopped when a cumulative amount of time with an impedance value over the impedance cumulative time threshold value reaches a sealing cycle duration limit.

Impedance mediated control of power delivery for electrosurgery

An adaptive algorithm monitors the rate of tissue impedance change during an electrosurgical procedure. Impedance levels are examined to determine an impedance ramp and/or slope rate, which indicates the rate at which a target tissue is undergoing a phase or state change. The level of electrosurgical energy applied to the target tissue is adjusted in real time. Energy is applied to the target tissue at levels that allow tissue phase or state change to occur in an optimum fashion. Undesired results such as thermal damage and defective sealing are mitigated. Another embodiment determines impedance achieved within a specific interval and adjusts the electrosurgical energy applied to the tissue after a threshold impedance has been maintained or exceeded for a predetermined interval. A further aspect of the invention provides mitigation during processing for partial tissue coverage of device electrodes or thin tissue.

Roseanne Varner

Papers

Impedance mediated control of power delivery for electrosurgery

Impedance mediated power delivery for electrosurgery