Electrosurgical instrument

• US 20030144652A1
• Filed: 11/09/2002
• Published: 07/31/2003
• Est. Priority Date: 11/09/2001
• Status: Active Grant

• Current Assignee: Ethicon Endo-Surgery, Inc. (Johnson & Johnson)
• Original Assignee: SurgRx, Inc. (Johnson & Johnson)
• Inventors: Shadduck, John H., Truckai, Csaba, Baker, James A.
• Granted Patent: US 6,926,716 B2
• Time in Patent Office: Days
• US Class Current: 606/28
• CPC Class Codes: A61B 17/32 Surgical cutting instruments A61B18/042 takes precedence; suture cutters A61B17/0467; instruments for ligaturing or cutting A61B17/128; instruments for rupturing the amniotic membrane A61B17/4208; specially adapted knives for eye surgery A61F9/0133
• CPC Class Codes: A61B 18/08 by means of electrically-heated probes
• CPC Class Codes: A61B 18/082 Probes or electrodes therefor
• CPC Class Codes: A61B 18/1442 Probes having pivoting end effectors, e.g. forceps
• CPC Class Codes: A61B 2018/00404 Blood vessels other than those in or around the heart
• CPC Class Codes: A61B 2018/00601 Cutting
• CPC Class Codes: A61B 2018/00619 Welding
• CPC Class Codes: A61B 2018/087 using semiconductors as heating element
• CPC Class Codes: A61B 2018/1455 having a moving blade for cutting tissue grasped by the jaws
• CPC Class Codes: A61B 2218/002 Irrigation

Abstract

A working end of a surgical instrument that carries first and second jaws for delivering energy to tissue. In a preferred embodiment, at least one jaw of the working end defines a tissue-engagement plane that contacts the targeted tissue. The cross-section of the engagement plane reveals that it defines (i) a first surface conductive portion or a variably resistive matrix of a temperature-sensitive resistive material or a pressure-sensitive resistive material, and (ii) a second surface portion coupled to a fixed resistive material that coupled in series or parallel to a voltage source together with the first portion. In use, the engagement plane will apply active Rf energy to ohmically heat the captured tissue until the point in time that a controller senses an electrical parameter of the tissue such as impedance. Thereafter, the controller switches energy delivery to the second surface portion that is resistively heated to thereby apply energy to tissue by conductive heat transfer.

Claims

1. A working end of a surgical thermotherapy instrument, comprising:

first and second jaw members moveable between an open position and a closed position, each jaw defining a jaw body and a jaw surface for engaging tissue;

a first body portion of said at least one jaw comprising a conductive electrode exposed in the jaw surface coupled to a voltage source, the first body portion for providing ohmic heating in engaged tissue; and

a second body portion of at least one jaw comprising a material exposed in the jaw surface having a fixed resistance to electrical flow therethrough, the second body portion for conducting heat from the jaw surface to engaged tissue.

2. The working end of claim 1 wherein said first body portion comprises less that about 50% of the jaw surface.

3. The working end of claim 1 wherein said first body portion comprises less that about 20% of the jaw surface.

4. The working end of claim 1 wherein said second body portion comprises greater that about 50% of the jaw surface.

5. The working end of claim 1 wherein said second body portion comprises greater that about 80% of the jaw surface.

6. The working end of claim 1 further comprising a controller for selectively delivering energy from the voltage source to either the first body portion or the second body portion.

7. The working end of claim 1 wherein said first and second body portions are coupled in serial to said voltage source.

8. The working end of claim 1 wherein said first and second body portions are coupled in parallel to said voltage source.

9. The working end of claim 1 further comprising a third body portion of said at least one jaw that comprises a material having a variable resistance to electrical flow therethrough.

10. The working end of claim 9 wherein said material having a variable resistance to electrical flow therethrough is a temperature-sensitive resistive material.

11. The working end of claim 1 further comprising a third body portion of at least one jaw surface that comprises a material that defines a pressure-sensitive variable resistance to electrical flow therethrough.

12. The working end of claim 11 wherein said first, second and third body portions of said at least one jaw are coupled in serial to said voltage source.

13. The working end of claim 11 wherein a pair of said first, second and third body portions of said at least one jaw are coupled in serial to said voltage source.

14. A working end of a surgical thermotherapy instrument, comprising:

a working end defining an engagement surface for contacting tissue;

a first body portion of the working end comprising a conductive electrode exposed in the engagement surface coupled to a voltage source, the first body portion for providing ohmic heating in contacted tissue; and

a second body portion of the working end comprising a material exposed in the engagement surface having a fixed resistance to electrical flow therethrough, the second body portion for conducting heat from the engagement surface to contacted tissue.

15. The working end of claim 14 wherein said first and second body portions are coupled in serial to said voltage source.

16. The working end of claim 14 wherein said first and second body portions are coupled in parallel to said voltage source.

17. The working end of claim 15 further comprising a control system for providing energy to delivery to either the first body portion or the second body portion.

18. A method for controlled thermotherapy of engaged tissue, comprising the steps of:

providing a working end that defines an engagement surface that contacts tissue, the engagement surface having a first body portion comprising at least one conductor coupled to a voltage source for ohmic heating of tissue and a second body portion of a resistive material coupled to said voltage source for heating the mass of the working end;

engaging tissue with the engagement surface; and

delivering Rf energy to said first body portion to thereby ohmically heat the engaged tissue;

sensing a selected electrical parameter of the engaged tissue with controller system; and

switching energy delivery to the second body portion to thereby conductively heat the engaged tissue.

19. The method of claim 18 further comprising the step of switching between energy delivery back and forth between the first and second body portions in response to the selected electrical parameter.

20. The method of claim 18 wherein electrical parameter is selected from the class consisting of impedance, temperature and/or rates of change thereof.