Bipolar electrosurgical knife

• US 4,202,337 A
• Filed: 06/14/1977
• Issued: 05/13/1980
• Est. Priority Date: 06/14/1977
• Status: Expired due to Term

• Current Assignee: Concept, Inc. (Bristol-Myers Squibb Company)
• Original Assignee: Concept, Inc. (Bristol-Myers Squibb Company)
• Inventors: Jenkins, David A., Clark, David E., Hren, John J., Johnson, Paul F. III, Degler, Howead E. Jr.
• Primary Examiner(s): Cohen, Lee S.
• Application Number:
  US05/806,529
• Time in Patent Office: 1,064 Days
• Field of Search: 128/303.13-303.18, 128/405, 128/800
• US Class Current: 606/48
• CPC Class Codes: A61B 18/1402 Probes for open surgery

Abstract

An electrosurgical instrument for cutting, spot coagulation and point coagulation comprising a nonconductive handle which holds a blade assembly comprising a plurality of electrodes and an insulation member separating the electrodes.

The blade assembly comprises an active center electrode of specified thickness with a recessed tip and is mounted to an extruded insulation member so that it extends outwardly from the insulation member to form a cutting edge.

Split side return electrodes are symmetrically mounted to the insulation member and separated from the center electrode by the insulation member. The electrode area ratio of the return electrode area to the active electrode area falls between 0.70 and 2.0 allowing consistent bipolar operation.

The electrodes are connected inside the nonconductive handle to a circuit whose output consists of a high frequency electrical current which forms a circuit through tissue intervening between and in contact with the electrodes when the instrument is used.

Claims

1. An electrosurgical instrument of the type adapted to be selectively connected to a source of energy such as a high frequency electrical current for use in cutting, coagulating or otherwise treating human tissue or the like comprising an insulative handle and blade assembly mounted in said handle and extending therefrom, said blade assembly comprising an insulation member having an alumina composition of at least 96% purity, a linearly shaped active center electrode mounted to said insulation member, a plurality of return electrodes symmetrically mounted to said insulation member spaced apart from said center electrode and each other, a portion of said center electrode extending beyond said insulation member, said center electrode portion and sides of said insulation member forming a blade assembly having a beveled edge, means for connecting said electrodes to an energy source means so that an output circuit of a source of energy comprising a high frequency electrical current is completed through body tissue, said energy source means comprising means to selectively generate and conduct wave forms to said electrodes for performance of the desired electrical function.

2. A surgical instrument as claimed in claim 1 wherein said center electrode is stainless steel.

3. A bipolar electrosurgical device adapted for connection to a high frequency electrical generator having active and return output terminals, said device being used to cut, coagulate, or otherwise treat human tissue or the like, said device comprising a high purity composition of about 96% alumina insulative electrode support means defining a beveled surface;

an active electrically conductive electrode responsive to said active output terminal and return electrodes comprising conductive elements responsive to said return output terminal, said electrodes being supported by said electrode support means, said return electrodes being symmetrically disposed with respect to said active electrode with the active electrode positioned intermediate the return electrodes, said active and return electrodes being rigidly supported a fixed distance apart by said electrode support means, said electrodes being adapted for electrical connection to said tissue, the ratio of the return electrode area adapted to electrically connect to said tissue as compared to the active electrode area adapted to electrically connect to said tissue being in the range of approximately 0.70 to 2.0, and means for connecting said active electrode to said active output terminal and said return electrodes to said return output terminal so that said electrosurgical device can be used to treat said tissue.

4. An electrosurgical device as claimed in claim 3 wherein said ratio has a preferred range of 1.1-1.5.

5. An electrosurgical device as claimed in claim 3 wherein said return electrodes comprise a plurality of spaced apart parallel conductive elements at least 0.015 inches in width positioned on said electrode support means, said electrode support means defining a groove which is located between said spaced conductive elements separating said spaced conductive elements.

6. A bipolar electrosurgical device as claimed in claim 5 wherein said plurality of conductive elements include end sections forming an "L" shaped configuration.

7. An electrosurgical device as claimed in claim 3 wherein said active electrode element is shaped like a tuning fork and mounted around said insulative electrode support means.

8. An electrosurgical device as claimed in claim 7 wherein said active electrode element has its forward cutting edges beveled inward.

9. An electrosurgical device as claimed in claim 3 wherein said insulative electrode support means can withstand a stress of 50,000 p.s.i. and has a dielectric strength greater than 200 volts/mil at 25°

C. and 60 MH_z.

10. An electrosurgical instrument adapted for connection of a high frequency electrical generator having active and return output terminals, said instrument being used to cut, coagulate or treat animal tissue and comprising an insulated handle and blade assembly mounted in said handle and extending from said handle, said blade assembly comprising a linearly formed insulation member, an active electrode mounted to said insulation member and extending from at least two sides of said insulation member 0.0075 to 0.02 inches, said insulation member having an Al₂ O₃ composition ranging from 96 to 99% plus purity, a plurality of spaced outer return electrodes secured to said insulation member and symmetrically positioned on said insulation member, the ratio of the area of said return electrodes to the area of said active electrode ranging from 1.1-2.0, means for connecting said electrodes to said generator so that an output circuit comprising a high frequency electrical current is completed through tissue intervening between and in contact with said electrodes, said generator comprising means to generate cutting or coagulating wave forms to said electrodes and switch means adapted to selectively transmit said wave forms into said electrodes for performance of the desired electrosurgical function.

11. A surgical instrument as claimed in claim 10 wherein said outer return electrodes are a nobel metal combination about 0.015 to 0.018 inches in width and are positioned parallel to each other.

12. A blade assembly suitable for use with a bipolar electrosurgical instrument comprising a linearly shaped active center electrode ranging from 0.0075 to 0.015 inches in thickness and having a substantially "U" shaped configuration, an alumina insulation member of at least 96% purity defining a plurality of grooves, said electrode being mounted in said grooves formed in said alumina insulation member and extending from said alumina insulation member to form a blade edge, a plurality of spaced apart symmetrical side return electrodes secured to opposite sides of said insulation member to form a ratio R with respect to the active center electrode defined by:

space="preserve" listing-type="equation">R=Return electrode area/Active electrode area

with R ranging in value from 1.2-1.8, said center electrode and insulation member forming a blade edge.

13. A blade assembly as claimed in claim 12 wherein said insulation member has a material composition of Al₂ O₃ 99.5% plus purity.

14. An electrosurgical instrument comprising an insulative handle, a blade assembly mounted in said handle and extending therefrom, said blade assembly comprising an alumina insulation structure of at least 96% purity having a dielectric strength greater than 200 volts/mil at 25°

C. and 60 MHz and withstanding a compressive stress of at least 50,000 p.s.i., a linearly shaped active center electrode mounted to and extending from said insulation structure, a plurality of return electrodes symmetrically mounted to said insulation structure spaced apart from said center electrode and each other, said center electrode and insulation structure forming a blade assembly having a beveled edge with the center electrode and return electrodes extending near the tip of the blade assembly and the return electrodes being located proximate to the beveled edge of the insulation structure and means for connecting said electrodes to an energy source means so that an output circuit of a source of energy comprising a high frequency electrical circuit is completed through body tissue.

15. A bipolar electrosurgical device adapted for connection to a high frequency electrical generator having active and return output terminals, said device being used to cut, coagulate, or otherwise treat human tissue or the like, said device comprising an insulative electrode support means of at least 96% purity alumina defining a tip with a front section and beveled sides, said tip being beveled at an approximately 45°

angle with respect to the front section;

an active electrode formed with an outer edge having a thickness not greater than 15 mils responsive to said active output terminal and return electrodes comprising conductive elements responsive to said return output terminal, said electrodes being supported by said electrode support means, said return electrodes being symmetrically disposed with respect to said active electrode with the active electrode positioned intermediate the return electrodes, said active and return electrodes being rigidly supported a fixed distance apart by said electrode support means, said electrodes being adapted for electrical connection to said tissue, the ratio of the return electrode area adapted to electrically connect to said tissue as compared to the active electrode area adapted to electrically connect to said tissue being in the range of approximately 0.70 to 2.0, and means for connecting said active electrode to said active output terminal and said return electrodes to said return output terminal so that said electrosurgical device can be used to treat said tissue.

16. A blade assembly suitable for use with a bipolar electrosurgical instrument comprising a linearly shaped active center electrode body, said electrode body being mounted in a beveled alumina insulation member of at least 96% purity, said electrode body having an exposed width ranging from 0.008 to 0.02 inches, a plurality of spaced apart split symmetrical side return electrodes secured to opposite sides of said insulation member to form a ratio R with the active electrode defined by:

space="preserve" listing-type="equation">R=Return electrode area/Active electrode area

with R ranging in value from 0.7-2.0, said center electrode body being beveled and mounted to said insulation member to form a cutting blade edge, and said return electrodes and said insulation member forming a coagulation blade edge.

17. A blade assembly as claimed in claim 16 wherein said beveled alumina insulation member and said beveled center electrode body form an angle of about 60°

to define the cutting blade edge.

18. A blade assembly suitable for use with a bipolar electrosurgical instrument comprising a linearly shaped active center electrode body ranging from 0.0075 to 0.015 inches in thickness mounted to an alumina insulation member of at least 96% purity, said insulation member defining beveled side portions forming an angle of about 60°

and an angled front section, a plurality of spaced apart symmetrical side return electrodes secured to opposite sides of said insulation member forming an area ratio R with respect to the active center electrode which is defined by;

space="preserve" listing-type="equation">R=Return electrode area/Active electrode area

with R ranging in value from 0.70-2.0, said center electrode and the beveled side portions of said insulation member forming a blade edge for cutting and said side return electrodes forming a coagulation edge.

19. A bipolar electrosurgical instrument for cutting animal tissue comprising an insulative handle and blade assembly mounted in and extending from said handle, said blade assembly comprising a beveled insulation member having an Al₂ O₃ composition of greater than 96% purity, a linearly shaped active center electrode ranging from 0.005 to 0.015 inches in thickness mounted to said insulation member and extending beyond said insulation member, a plurality of return electrodes symmetrically mounted to said insulation member spaced apart from said center electrode and each other, said center electrode and insulation member forming a blade assembly with the proximity of the return electrodes to the bevel allowing shallow cutting when the tissue is under tension, means for connecting said electrodes to an energy source means so that an output circuit of a source of energy comprising a high frequency electrical circuit is completed through body tissue.