Bipolar electrosurgical knife

• US 4,228,800 A
• Filed: 04/04/1978
• Issued: 10/21/1980
• Est. Priority Date: 04/04/1978
• 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, Howard E. Jr.
• Primary Examiner(s): Cohen, Lee S.
• Application Number:
  US05/893,422
• Time in Patent Office: 931 Days
• Field of Search: 128/303.13-303.18, 128/40 J, 128/800
• US Class Current: 606/48
• CPC Class Codes: A61B 18/1402 Probes for open surgery
• CPC Class Codes: A61B 2018/00107 Coatings on the energy applicator
• CPC Class Codes: A61B 2018/00922 by switching or controlling the treatment energy directly within the hand-piece
• CPC Class Codes: A61B 2018/1412 Blade

Abstract

An electrosurgical instrument comprising a handle which holds a blade assembly comprising a plurality of electrodes and insulation members positioned between the electrodes.

The blade assembly comprises a center electrode of specified thickness, insulation members secured to the center electrode and a plurality of side electrodes secured to the insulation members. The center electrode and insulation members are cut to form a cutting edge having a composite angle of less than 120° thus allowing easier electrosurgical performance.

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. A bipolar electrosurgical instrument comprising an electrically insulated housing, constructed of a nonconductive material and having a substantially pencil shaped configuration, a blade assembly mounted in said housing and projecting from said housing, said blade assembly comprising a center electrode, insulation means on opposite sides of said electrode and side electrodes ranging in width from 0.047 inches to 0.100 inches secured to said insulation means so that they are symmetrically disposed with respect to said center electrode and separated from said center electrode by said insulation means, said blade assembly center electrode being formed with a substantially rectangular linear shape with linearly oriented beveled edges and connected to said insulation means, said insulation means comprising two insulator members of substantially rectangular linear shape positioned on each side of said center electrode with aligned beveled edges, said two insulator members being composed of at least 99% pure Al₂ O₃, a source of energy, means for connecting said electrodes to said source of energy so that an output circuit of the source of energy comprising a high frequency electrical current is completed through tissue intervening between and in contact with said electrodes, said side electrodes being shorted together within said housing and acting as return electrodes during operation of this instrument and switch means connected to said source of energy for selectively energizing said electrodes.

2. A surgical instrument as claimed in claim 1 wherein said center electrode is tantalum and said side electrodes are silver.

3. A surgical instrument as claimed in claim 1 wherein said center electrode is stainless steel and said side electrodes are silver.

4. A surgical instrument as claimed in claim 1 wherein said center electrode has a beveled cutting edge forming a 60°

angle.

5. A surgical instrument as claimed in claim 1 wherein said center electrode has a thickness ranging from 0.005 to 0.015 inches.

6. A surgical instrument as claimed in claim 1 wherein said center electrode has a thickness of substantially 0.010 inches.

7. A surgical instrument as claimed in claim 1 wherein said center electrode and insulator members edge form a blade assembly edge having a wedge angle which is not greater than 120°

.

8. A surgical instrument as claimed in claim 1 wherein said center electrode and insulator members edges form a blade assembly cutting edge having a wedge angle of substantially 60°

.

9. A surgical instrument as claimed in claim 1 wherein said two insulator members are bonded to said center electrode on opposite sides of said center electrode to form a residual compressive stress in the Al₂ O₃ insulator members.

10. A surgical instrument as claimed in claim 9 wherein said bonding is with a high temperature epoxy.

11. A bipolar electrosurgical instrument comprising an insulated handle, and blade assembly mounted in said handle and projecting from said handle, said blade assembly comprising a linearly shaped, center electrode body ranging from 0.005 to 0.015 inches in thickness, platelike insulation members composed of at least 99% pure Al₂ O₃ secured to opposite sides of said center electrode and outer electrodes of silver composition secured to said insulation members in symmetrical relationship to said center electrode and separated from said center electrode by said insulation members, said center electrode and insulation members being beveled to form a blade assembly with proximal and distal ends having an edge wedge angle which does not exceed 120°

with the center electrode extending past the insulation members at the distal end and edges of the blade assembly, a source of energy, means for connecting said electrodes to said source of energy so that an output circuit of said source of energy comprising a high frequency electrical current is completed and maintained through tissue intervening between and in contact with said electrodes, said source of energy comprising means to selectively generate wave forms to said electrodes and switch means adapted to select said wave forms for transmission into said electrodes for performance of the desired electrosurgical function.

12. A surgical instrument as claimed in claim 11 wherein said center electrode is tantalum and said insulation members are Al₂ O₃.

13. A surgical instrument as claimed in claim 11 wherein said center electrode is stainless steel and insulation members are Al₂ O₃.

14. A bipolar electrosurgical instrument comprising an insulated handle, and blade assembly mounted in said handle and projecting from said handle, said blade assembly comprising a linearly shaped center electrode body about 0.010 inches in thickness with a beveled edge, insulation members having a composition of Al₂ O₃ of at least 99% purity bonded to opposite sides of said center electrode with a high temperature epoxy and outer electrodes secured to said insulation members and separated by said insulation members from said center electrode, said electrodes and insulation members forming a blade assembly in which the edges of the insulation members are beveled and cooperate with the center electrode beveled edge to form an angle of about 60°

, a source of energy, means for connecting said electrodes to said source of energy so that an output circuit of the source of energy comprising a high frequency electrical current is completed through tissue interventing between and in contact with said electrodes, said source of energy comprising means to generate cutting 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.

15. A surgical instrument as claimed in claim 14 wherein said outer electrodes are about 0.062 inches in width.

16. A bipolar blade assembly suitable for use with a bipolar electrosurgical instrument comprising a linearly shaped center electrode body with a substantially semicircular distal end ranging about 0.010 inches in thickness with a beveled edge, two identical insulation members of lesser length and width than said center electrode formed with an insulator material of about 99% pure Al₂ O₃ composition, said insulation members presenting a substantially trapezoidal cross-section configuration and defining beveled edges, said insulation members being secured to opposite sides of said center electrode leaving a center electrode tip area exposed and beveled side edges of the center electrode exposed and outer electrodes of lesser length and width than said center electrode secured to said insulation members and separated from said center electrode by said insulation members, said outer electrodes being symmetrically disposed with respect to said center electrode and formed with a width ranging from 0.047 to 0.10 inches, said center electrode and insulation members forming a blade wedge angle of about 60°

, a source of energy, means for connecting said electrodes to said source of energy so that an output circuit of the source of energy comprising a high frequency electrical current is completed through tissue intervening between and in contact with said electrodes, said source of energy comprising means to generate cutting 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.

17. A blade assembly as claimed in claim 16 wherein said center electrode is tantalum and said outer electrodes are silver with said center electrode, insulation members and outer electrodes being bonded together with a high temperature epoxy.