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

Summary Intracerebral haemorrhage accounts for about 10–15% of all strokes and is associated with high mortality and morbidity. No successful phase 3 clinical trials for this disorder have been completed. In the past 6 years, the number of preclinical and clinical studies focused on intracerebral haemorrhage has risen. Important advances have been made in animal models of this disorder and in our understanding of mechanisms underlying brain injury after haemorrhage. Several therapeutic targets have subsequently been identified that are now being pursued in clinical trials. Many clinical trials have been based on limited preclinical data, and guidelines to justify taking preclinical results to the clinic are needed.

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Intracerebral haemorrhage: mechanisms of injury and therapeutic targets

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

An ultrasound catheter with a lumen for fluid delivery and'or fluid evacuation, and ultrasound radiating elements is used for the delivery of therapeutic compounds to a target location. After the catheter is inserted into a cavity, a therapeutic compound can be delivered to the target location via selective activation of the ultrasound radiating elements. Selective activation of the ultrasound radiating elements can be used to cause fluid flow in a direction proximal and/or distal the catheter. Moreover, selective activating can be used to maintain fluid between certain of the ultrasound radiating elements.

Method and apparatus for drug delivery to a target site

Blood pH measurements present unique challenges due to the lack of a method to determine accuracy. Therefore an operational pH scale has been defined with the use of accepted pH standard buffer solutions in order to achieve precision and consistency. Historically, blood pH has been measured electrochemically with the glass electrode, in-vitro. The glass electrode is subject to drifts and to extraneous potentials that adds uncertainties to the measured values and must rely on frequent recalibrations to provide precision and consistency. A recent commercial entry, the fiber optic fluorescent pH sensor avoids these problems. The result is a stable sensor capable of continuous in-vivo monitoring of blood pH in spite of the intricacies introduced by the use of the operationally defined pH.

Optical pH Measurements In Blood

In one embodiment, a method for treating a vascular occlusion in a patient's body comprises exposing the vascular occlusion to an external ultrasonic energy field that is generated outside the patient's body. The method further comprises positioning an ultrasound radiating member in the patient's body in the vicinity of the vascular occlusion. The method further comprises exposing the vascular occlusion to an internal ultrasonic energy field that is generated by the ultrasound radiating member. The method further comprises using the ultrasound radiating member to detect a first characteristic of the external ultrasonic energy field. The method further comprises adjusting a second characteristic of the external ultrasonic energy field based on the detected first characteristic of the external ultrasonic energy field.

Douglas R. Hansmann

Papers

Method and apparatus for drug delivery to a target site

Optical pH Measurements In Blood

Treatment of vascular occlusions by interacorporeal and extracorporeal application of ultrasound