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

Various embodiments are directed to an apparatus, system, and method for driving an end effector coupled to an ultrasonic transducer in a surgical instrument. The method comprises generating a first ultrasonic drive signal by a generator coupled to an ultrasonic drive system, 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 is different from the second drive signal over the respective 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 configured to couple to an ultrasonic instrument. The system comprises a generator coupled to an ultrasonic instrument. The ultrasonic instrument comprises an ultrasonic drive system comprising an ultrasonic transducer coupled to a waveguide and an end effector coupled to the waveguide, and wherein the ultrasonic drive system is configured to resonate at a resonant frequency.

Ultrasonic device for cutting and coagulating with stepped output

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 conductive, non-stick coating (62) is provided using a ceramic material which is conductive, flexible and provides a surface which exhibits the property of lubricity. A room or near room temperature manufacturing process produces a coating of titanium nitride on a substrate, where the coating is amorphous if the substrate is a solid material including plastics, composites, metals, magnets and ceramics, enabling the substrate to bend without damaging the coating. The coating can also be applied as a conformal coating on a variety of substrate shapes, depending upon the application. The coating is biocompatible and can be applied to a variety of medical devices.

Method and apparatus for providing a conductive, amorphous non-stick coating

An apparatus and method for a centrifugal pump (10) for pumping sensitive biologic fluid, which includes (i) an integral impeller and rotor (21) which is entirely supported by an integral combination of permanent magnets and electromagnetic bearings (52, 54) and rotated by an integral motor (40), (ii) a pump housing and arcuate passages (32, 34, 36) for fluid flow and containment, (iii) a brushless driving motor (40) embedded and integral with the pump housing, (iv) a power supply, and (v) specific electronic sensing of impeller position, velocity or acceleration using a self-sensing method and physiological control algorithm for motor speed and pump performance based upon input from the electromagnetic bearing currents and motor back emf -- all fitly joined together to provide efficient, durable and low maintenance pump operation. A specially designed impeller and pump housing provide the mechanism for transport and delivery of fluid through the pump to a pump output port with reduced fluid turbulence.

Hybrid magnetically suspended and rotated centrifugal pumping apparatus and method

A pump for pumping sensitive fluids, such as blood, having no mechanical contact between the impeller and any other structure. The pump comprises a pump housing (4), an impeller (7) disposed within the pump housing, a magnetic bearing system (5, 6) for supporting and stabilizing the impeller (7) in five degrees of freedom, and a conformally shaped magnetically linked motor for rotating the impeller (7). The magnetic bearing system (5, 6) and motor advantageously comprise electromagnets and permanent magnets (18) for stability and control of the impeller (7) and to reduce size, weight and pump power consumption. Permanent magnets (18) and electromagnets are disposed on the pump housing (4) and permanent magnets (18) are disposed on the impeller (7) such that by controlling electric current through the electromagnets on the housing, the magnetically suspended impeller (7) functions as the rotor and the housing as the stator of a D.C. motor. The system advantageously allows for sensing of relative impeller position and dynamic properties without the need for additional sensors.

Implantable centrifugal blood pump with hybrid magnetic bearings

An inventive blood pump in accordance with this invention includes a housing that has inlet and outlet ports for receiving and discharging blood A rotor is positioned in the housing's interior for pumping blood between the housing's inlet and outlet ports, with the rotor being capable of motion in three translational and three rotational axes An assembly for magnetically suspending and rotating the rotor in a contact-free manner with respect to the housing includes only one electromagnetic bearing that actively controls motion of the rotor with respect to one axis selected from the rotor's three translational and three rotational axes, an electromagnetic motor that actively drives motion of the rotor with respect to one of its three rotational axes, and magnetic bearings for passively controlling motion of the rotor with respect to the remaining four of its translational and rotational axes The inventive blood pump can also be incorporated into an artificial heart

Pump having a magnetically suspended rotor with one active control axis

The response of a continuous flow magnetic bearing supported ventricular assist device, the CFVAD3 (CF3) to human physiologic pressure and flow needs is varied by adjustment of the motor speed. This paper discusses a model of the automatic feedback controller designed to develop the required pump performance. The major human circulatory, mechanical, and electrical systems were evaluated using experimental data from the CF3 and linearized models developed. An open-loop model of the human circulatory system was constructed with a human heart and a VAD included. A feedback loop was then closed to maintain a desired reference differential pressure across the system. A proportional-integral (PI) controller was developed to adjust the motor speed and maintain the system reference differential pressure when changes occur in the natural heart. The effects of natural heart pulsatility on the control system show that the reference blood differential pressure is maintained without requiring CF3 motor pulsatility.

P. Khanwilkar

Papers

Method and apparatus for providing a conductive, amorphous non-stick coating

Hybrid magnetically suspended and rotated centrifugal pumping apparatus and method

Implantable centrifugal blood pump with hybrid magnetic bearings

Pump having a magnetically suspended rotor with one active control axis

Motor feedback physiological control for a continuous flow ventricular assist device.