Electrosurgical device

• US 4,331,149 A
• Filed: 06/28/1976
• Issued: 05/25/1982
• Est. Priority Date: 01/23/1975
• Status: Expired due to Term

• Current Assignee: DENTSPLY International Incorporated (Astrazeneca PLC)
• Original Assignee: DENTSPLY International Incorporated (Astrazeneca PLC)
• Inventors: Gonser, Donald I.
• Primary Examiner(s): Cohen, Lee S.
• Application Number:
  US05/700,608
• Time in Patent Office: 2,157 Days
• Field of Search: 128/303.13, 128/303.14, 128/303.17, 128/303.18, 128/2.1 P, 128/908, 317/18 R, 317/18 A, 317/18 B, 317/18 D, 361/42
• US Class Current: 606/35
• CPC Class Codes: A61B 18/16 Indifferent or passive electrodes for grounding

Abstract

A radio-frequency electrosurgical device which includes an active electrode, a passive electrode, and a radio-frequency generator. The radio-frequency generator induces a radio-frequency potential on a primary winding of an isolation transformer. The secondary winding of the isolation transformer powers the active electrode. One end of the second winding of the isolation transformer is coupled to a return lead connected to the passive electrode and also is coupled to ground through a primary winding of a second transformer. If the passive electrode is disconnected from the return line, there can be an alternate radio-frequency current return path to ground, and a potential is developed across the primary winding of the second transformer. This potential is used to energize a relay to actuate an alarm and to disable the radio-frequency generator if the passive electrode becomes disconnected.

Claims

1. A radio-frequency electrosurgical device which comprises a radio-frequency generator having a power output means and a power return means for supplying a radio-frequency potential between the power output means and the power return means, an active power lead, means for coupling the active power lead to the power output means, a return lead, means for coupling the return lead to the power return means, an active electrosurgical electrode, means for coupling the active power lead to the active electrosurgical electrode to power the active electrosurgical electrode, a passive electrode, means for coupling the passive electrode to the return lead, alternate path return means for coupling the return lead to ground, an electrical shield surrounding the active power lead, means for connecting the shield to ground through the return lead and the alternate path return means, and monitor means in the alternate path return means for indicating a predetermined radio-frequency current return in the alternate path return means.

2. A radio-frequency electrosurgical device as in claim 1 wherein the active power lead is an inner conductor of a coaxial cable and the electrical shield is an outer conductor of the coaxial cable.

3. A radio-frequency electrosurgical device as in claim 1 wherein the means for indicating a predetermined radio-frequency current return includes means for disabling the radio-frequency generator from powering the active power lead when the radio-frequency current return in the alternate path return means exceeds a predetermined value.

4. A radio-frequency electrosurgical device as in claim 1 wherein said means for coupling the active power lead to the power output means includes a first capacitor, and wherein said means for coupling the passive electrode to the return lead includes a second capacitor.