Concept, Inc.

Medical Research Associates, Ltd. #2

Medical Research Associates, Ltd.

Medical Research Associates, Ltd. #1

Frederick W Rexroth

F Barry Bays

Paul J Altnether

Gary R Hoss

An electrolyte fluid purging electrosurgical device for use with an electrode holder connected to an electrical power source and to a source of a non-electrically conductive fluid and a method of use are disclosed. The fluid purging electrosurgical device enables electrosurgery at a surgical site where an area proximate the surgical site is surrounded by an electrically conductive fluid such as saline irrigation fluids, body fluids, certain injectables and the like. The fluid purging electrosurgical device comprises an electrode shaft with an electrode shaft connector electrically connecting a first end of the electrode shaft to an electrode holder. An insulating material provides electrical insulation between a second end of the electrode shaft and the electrode holder. The insulating material is positioned on the electrode shaft to expose a portion of the second end of the electrode shaft to define an electrode tip to provide electrical current to the surgical site. A duct means is connected to the source of the non-electrically conductive fluid and extends along the electrode shaft to deliver the non-electrically conductive fluid to a region immediately proximate the electrode tip to displace the electrically conductive fluid at the position of the electrode tip in the surgical site to enable electrosurgical treatment thereat.

Electrolyte purging electrode tip

Electrosurgical method using an electrically conductive fluid

A microprocessor controlled electrosurgical generator provides plural ground-isolated and mutually isolated monopolar r-f cutting signals for respective surgical pencils to permit plural surgeons to use the same generator while maintaining independent control over output power and mode selection. A bipolar output signal is also isolated from ground and from the monopolar signals so that the removal of the dispersive patient return pad is not required when changing between monopolar and bipolar operation. Adjustment of the r-f cutting signal power level is effected by providing an adjustable d.c. bias level for an output amplifier. The d.c. bias level is derived from an a.c. control signal which is duty-cycle modulated in accordance with selected r-f power level settings. Digital phase control is employed to change the control signal duty cycle by subdividing the control signal cycle into precise count intervals and triggering a gate to pass the control signal through a rectifier to a filter for only the selected number of count intervals in each cycle as determined by a pre-settable counter. Negative feedback of the cutting signal to the input terminal of the output amplifier provides system stability during open circuit operation.

Microprocessor controlled electrosurgical generator

A pencil for electrosurgical generators includes a push button switch structure useful in selectively bridging spaced printed circuit contacts in spite of oxidized film on the contact surface. A movable concave disk has a sharp peripheral edge that is forced against the contact surface during switch actuation to cut through the oxidized film and reliably bridge the contacts. The disk is carried by an axial projection forming part of a resilient dome surrounding the projection. The dome includes a radial flange which is compressed against the printed circuit board by an annular member projecting axially inwardly from the housing wall around the outside of the dome. The closed end of the dome is connected to the flange by a frusto-conical connecting wall adapted to flex to permit the closed dome end to be pushed toward the open dome end during switch actuation.

Pencil for electrosurgical generator

An electrosurgical generator, having particular utility in surgical procedures on human joints, is provided with an output impedance in the range of 600 to 2,500 Ohms in order to efficiently transfer energy to the high impedance joint. The relatively high output impedance permits much lower power settings to be empolyed than are required by conventional electrosurgical generators so that little or no damage results in surrounding tissue. In the preferred embodiment, the output impedance range is 900 to 1,400 Ohms and is provided by an isolation transformer in which the turns ratio is selected to obtain the desired generator output impedance across the transformer secondary winding.

Electrosurgical generator

An electrosurgical generator, having particular utility in arthroscopic surgical procedures, is provided with a rapid start capability in its pure cut mode by inhibiting secondary modulation for an initial starting interval during which an uninterrupted high frequency cutting signal is applied to the output terminals. Upon expiration of the starting interval, the secondary modulation takes effect to modulate the cutting signal with a low frequency repetitive signal having a predetermined duty cycle. In addition, the generator output isolation transformer is arranged to provide an output impedance of at least 1,000 Ohms to match the impedance of human joints on which arthroscopic surgery is performed.

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Dunedin, FL, United States of America

Frederick W Rexroth