Resistively heated cutting and coagulating surgical instrument

• US 5,807,392 A
• Filed: 03/13/1997
• Issued: 09/15/1998
• Est. Priority Date: 03/02/1995
• Status: Expired due to Term

• Current Assignee: Philip E. Eggers
• Original Assignee: Philip E. Eggers
• Inventors: Eggers, Philip E.
• Primary Examiner(s): Cohen, Lee S.
• Application Number:
  US08/816,300
• Time in Patent Office: 551 Days
• Field of Search: 606/28, 606/29, 606/31, 219/230, 219/233, 219/235-239, 219/241
• US Class Current: 606/31
• CPC Class Codes: A61B 17/3211 Surgical scalpels, knives; Accessories therefor
• CPC Class Codes: A61B 18/082 Probes or electrodes therefor
• CPC Class Codes: A61B 18/10 Power sources therefor
• CPC Class Codes: A61B 18/14 Probes or electrodes therefor
• CPC Class Codes: A61B 2018/00083 low, i.e. electrically insulating
• CPC Class Codes: A61B 2018/00119 with metal oxide nitride
• CPC Class Codes: A61B 2018/00136 with polymer
• CPC Class Codes: A61B 2018/00178 Electrical connectors
• CPC Class Codes: A61B 2018/00642 with feedback, i.e. closed loop control

Abstract

A surgical instrument having a resistively-heated heating component responsive to a power source for generating thermal excitation effective for cutting tissue and carrying out hemostasis. The surgical instrument includes a support assembly having two leg extensions connected in heat transfer relationship with the heating component. Two thermal transition regions are provided within the heating component and have extents effective to provide a decreasing temperature gradient and to restrict temperature levels exhibited at the support assembly. The support assembly is formed of high thermally conductive material and extends from the transition regions to an elongate shaft. This shaft is in heat transfer relationship with the support assembly and is formed from a high thermally conductive material. Together, the shaft and support assembly act as a heat buffer such that temperature levels exhibited at the support assembly are restricted to levels atraumatic to tissue while the heating component is heated to temperatures effective for cutting and hemostasis. A hand engagable handle connects to the shaft. The surgical instrument may be powered from existing, conventional electrosurgical generators having bipolar outputs, and, in this regard, additionally includes circuit components selected for effecting power transfer impedance matching between the electrosurgical generator and the heating component.

Claims

1. A system for carrying out the thermal and hemostatic cutting of tissue, comprising:

an electrosurgical generator having bipolar output terminals exhibiting a load impedance to voltage characteristic, said generator exhibiting an operating frequency range characteristic at said output terminals within a range from about 350 KHz to 1 MHz;

a surgical instrument including an electrical resistance heating component having a region responsive to an applied variable voltage and current to attain a temperature below Curie temperature effective to cut said tissue upon entering contact therewith and exhibiting a predetermined load impedance to said current;

a support assembly coupled at a first end with said heating component for effecting its support and applying said current thereto, and having a shaft portion with electrical input terminals disposed at a second end;

a hand engageable instrument handling portion having circuit components selected for effecting power transfer impedance matching within said range of frequencies between said bipolar output terminals and said heating component, said circuit components including a transformer having a primary to secondary turns ratio selected within a range of about 5;

1 to about 10;

1 and including a capacitor coupled with said transformer having a capacitance value selected with respect to said operating frequency range for optimizing power transfer to said heating component, said instrument handling portion having an instrument output coupled with said support assembly electrical input terminals, and having an instrument input; and

an elongate cable connectable in electrical power transfer relationship between said bipolar output terminals of said electrosurgical generator and said instrument input of said instrument handling portion.

2. The system of claim 1 in which:

said electrical resistance heating component is formed of thermally autoregulating material; and

said electrosurgical generator given load impedance to voltage characteristic promotes the thermal autoregulation of said electrical resistance heating component.

3. The system of claim 1 in which:

said instrument output of said instrument handling portion includes two electrical output connectors which are removably connectable in electrical communication with said electrical input terminals of said support assembly;

said instrument input of said instrument handling portion includes two electrical input connectors; and

said cable includes two connectors removably connectable in electrical communication with said two electrical input connectors.