Electrosurgery instrument

• US 3,875,945 A
• Filed: 11/02/1973
• Issued: 04/08/1975
• Est. Priority Date: 11/02/1973
• Status: Expired due to Term

• Current Assignee: Joshua Friedman
• Original Assignee: Joshua Friedman
• Inventors: Friedman, Joshua
• Primary Examiner(s): Gaudet, Richard A.
• Assistant Examiner(s): Cohen, Lee S.
• Application Number:
  US05/412,292
• Time in Patent Office: 522 Days
• Field of Search: 128/303.14,303.13,303.17,303.18,303.19,412R,420
• US Class Current: 606/45
• CPC Class Codes: A61B 18/1206 Generators therefor
• CPC Class Codes: A61B 2018/1253 monopolar

Abstract

An electrosurgery instrument having a radio frequency oscillator energized from a power supply controlled by a switching arrangement to produce either dc, full wave rectified ac, or half-wave rectified ac at its output, depending upon whether it is desired to operate in the cut, coagulate, or fulgurate modes, respectively. The level of output voltage of the power supply may be set to any value within a range and thereafter increased by a fixed percentage upon the operation of a remote control switch. The level of output voltage in any mode of operation, once set, is regulated by a feedback control circuit to minimize sparking at the electrode tip. The oscillator output is coupled to an operating probe through an impedance transformer and coaxial cable designed to deliver maximum radio frequency power to the patient without the use of a ground plate. An indicating lamp is connected to points of different potential in the cable and within the probe in order to give a positive indication of the presence of radio frequency power at the probe tip.

Claims

1. An electrosurgery instrument connected to a source of ac power comprising a power supply including a switching means for selectively producing a full wave rectified output voltage, a half wave rectified output voltage and a substantially ripplefree dc output voltage from said source of ac power;

and ac oscillator having input terminals and output terminals;

an operating probe containing a cutting tip, means for coupling said oscillator output terminals to said cutting tip; and

regulator means for connecting a selected one of said output voltages to said oscillator input terminals including feedback means connected to said coupling means for maintaining a substantially constant voltage at said oscillator output terminals independent of variations in load impedance and power line voltage.

2. An electrosurgery instrument in accordance with claim 1 wherein said regulator means includes means for selectively adjusting the magnitude of output voltage from said power supply independent from said switching means.

3. An electrosurgery instrument in accordance with claim 2 wherein said regulator means further includes a feedback circuit comprising a rectifier connected to a portion of said oscillator output voltage, a filter network including a potentiometer connected to said rectifier, an inverting amplifier connected to the slide of said potentiometer and amplifier means controlled by said inverting amplifier for connecting a selected one of said power supply output voltages to said oscillator input terminals.

4. An electrosurgery instrument in accordance with claim 1 wherein said switching means includes a primary switch for selectively producing one of said output voltages at the output of said power supply and a remotely situated control switch having a first stage for energizing said oscillator input terminals with a selected one of said power supply output voltages and a second stage for simultaneously increasing the magnitude of said selected output voltage and for overriding said primary switch to produce said full wave rectified voltage at said output of said power supply when said primary switching means is arranged to select said ripple-free dc output voltage for application to said output of said power supply.

5. An electrosurgery instrument in accordance with claim 4 wherein said oscillator produces a voltage having a frequency in the range of 1 to 4 megacycles.

6. An electrosurgery instrument in accordance with claim 1 wherein said means for coupling said oscillator to said cutting tip includes an impedance transformer to effect a substantial match between the operating impedance seen by said cutting tip and the output impedance of said oscillator, a coaxial cable having a length less than one-quarter the wave length of said oscillator voltage connected between said cutting tip and said impedance transformer and an inductance having a magnitude in the range of 10-40 microhenrys serially connected between the terminal of said cable within said probe and said cutting tip.

7. An electrosurgery instrument in accordance with claim 1 wherein said operating probe comprises a hollow tubular housing fabricated from an electrical insulator material having a translucent band running circumferentially over a portion of its length and an interior lamp adjacent to said band having two terminals connected to points of different potential on said cable.