Medical Bipolar Electrode Assembly With A Cannula Having A Bipolar Active Tip And A Separate Supply Electrode And Medical Monopolar Electrode Assembly With A Cannula Having A Monopolar Active Tip And A Separate Temperature-Transducer Post

• US 20070016185A1
• Filed: 05/01/2006
• Published: 01/18/2007
• Est. Priority Date: 04/29/2005
• Status: Active Grant

• Current Assignee: Stryker Corporation
• Original Assignee: Stryker Corporation
• Inventors: Cramlet, Eland, Staunton, Douglas, Fickes, Nicole, Staats, Andy, Gamhewage, Chamara, Tullis, Philip
• Granted Patent: US 7,918,852 B2
• Time in Patent Office: Days
• US Class Current: 606/41
• CPC Class Codes: A61B 18/1477 Needle-like probes
• CPC Class Codes: A61B 2017/00212 using remote controls
• CPC Class Codes: A61B 2017/00867 shape memory effect for prostheses A61F2210/0014
• CPC Class Codes: A61B 2018/00434 Neural system
• CPC Class Codes: A61B 2018/0044 Spinal cord
• CPC Class Codes: A61B 2018/00821 measured by a thermocouple
• CPC Class Codes: C08L 2201/12 Shape memory

Abstract

An electrosurgical system preferably used for denervation procedures of nerve tissue has a control unit and a pluggable electrode assembly. The electrode assembly has a preferably disposable cannula and a preservable supply electrode assembly. The cannula has a tubular body that projects axially from a preferably pointed distal end for piercing tissue to a proximal end engaged to a first coupling assembly of the cannula. The body carries a first contact exposed directly to the nerve tissue and connected electrically to a terminal of the first coupling assembly. The supply electrode assembly has a second coupling assembly and a supply electrode that projects axially and removably into a through-bore of the body when the tool is in an operating state. The second coupling assembly carries a terminal that abuts the first coupling assembly when the coupling assemblies are mated. Preferably the supply electrode carries a temperature sensor for temperature measurement of the targeted tissue and processing by the control unit. Preferably, the electrode assembly also includes a stylet having a rod that fits into the through-bore of the body when the supply electrode assembly is removed and the tool is in a tissue penetrating state.

Claims

1. An electrode assembly comprising:

a cannula having a first coupling assembly and an elongated tubular body having a proximal end mounted to a hub of the first coupling assembly and projecting outward to a distal end;

first and second spaced apart and oppositely charged contacts disposed adjacent to the distal end;

a supply electrode having spaced apart proximal and distal ends, the supply electrode dimensioned to be slidably inserted in the body so as to be positioned to electrically contact the first contact;

a second coupling assembly attached to the proximal end of the supply electrode, the first and second coupling assemblies configured to releasably interlock;

a first conductive terminal seated in the hub and electrically connected to the second contact; and

a second conductive terminal attached to the second coupling assembly, the first and second conductive terminals being collectively positioned so that when the coupling assemblies interlock, the conductive terminals abut.

2. The electrode assembly set forth in claim 1 further comprising:

an inner tube of the body having the first contact; and

a through-bore defined by and extending co-axially with the inner tube.

3. The electrode assembly set forth in claim 2 wherein the supply electrode is disposed at least in-part in the through-bore.

4. The electrode assembly set forth in claim 3 further comprising an outer cylindrical shell of the supply electrode being in electrical contact with an inner cylindrical wall of the inner tube.

5. The electrode assembly set forth in claim 4 wherein a clearance between the outer cylindrical shell and the inner cylindrical wall is less than 0.001 inches.

6. The electrode assembly set forth in claim 3 wherein the through bore communicates through the distal end of the body.

7. The electrode assembly set forth in claim 6 wherein the distal end of the supply electrode is generally axially aligned to the distal end of the cannula when the first and second coupling assemblies are interlocked.

8. The electrode assembly set forth in claim 7 further comprising a temperature sensor orientated in the supply electrode near the distal end of the supply electrode for measuring tissue temperature.

9. The electrode assembly set forth in claim 7 further comprising first and second stops carried by the respective first and second coupling assemblies for maintaining consistent axial alignment of the distal end of the supply electrode with the distal end of the body.

10. A cannula for use with a matable supply electrode assembly having a coupling assembly connected to a cable that connects the supply electrode assembly to a control console, said cannula comprising:

an outer tube with opposed proximal and distal ends and a through bore;

an insulating sleeve disposed over the outer tube and proximal to the distal end so as to provide a distal active contact;

a hub attached to the proximal end of the outer tube, the hub dimensioned to releasably engage with the coupling assembly; and

a contact disposed in the hub for establishing a conductive path from the outer tube to a complimentary contact in the coupling assembly.

11. A cannula of an electrosurgical system having a matable supply electrode assembly for axial insertion into the cannula during a denervation procedure, said cannula comprising:

an axis;

an electrically conductive and elongated outer member spaced radially outward from the axis and extending axially forward to a first distal end of the outer member;

an electrically conductive inner tube disposed concentrically to the axis and radially inward from the outer member and extending axially forward to a second distal end of the inner tube;

an elongated electrical insulating member disposed radially between and extending longitudinally with the inner tube and the outer member; and

an axially extending through-bore is defined by the inner tube for receipt of the supply electrode assembly.

12. The cannula set forth in claim 11 further comprising:

a trailing proximal hub;

a first proximal end of the conductive outer member in the hub; and

a second proximal end of the conductive inner tube seated in the hub.

13. The cannula set forth in claim 12 further comprising a flexible electrical terminal housed in the hub and biased resiliently between the conductive outer member and an abutting terminal of the electrode assembly when the cannula is in the operational state.

14. The cannula set forth in claim 13 further comprising an inner cylindrical wall of the inner tube being in electrical contact with the electrode assembly when the cannula is in the operational state.

15. The cannula set forth in claim 14 wherein the conductive outer member is an outer tube disposed concentrically to the inner tube and the insulating member is an insulating inner sleeve disposed concentrically to the inner tube.

16. The cannula set forth in claim 15 further comprising:

an annular distal end of the inner sleeve that falls axially short of the second distal end of the inner tube; and

wherein the second distal end is a second ring-shaped contact facing radially outward and exposed directly to the tissue.

17. The cannula set forth in claim 16 wherein the annular distal end of the inner sleeve is tapered for less obtrusive penetration by the cannula into the tissue.

18. The cannula set forth in claim 16 further comprising an insulating outer sleeve located radially outward from the outer tube.

19. The cannula set forth in claim 18 further comprising:

an annular distal end of the outer sleeve that falls axially short of the fist distal end; and

wherein the first distal end is a first ring-shaped contact spaced axially rearward of the second ring-shaped contact by the insulating inner sleeve and being directly exposed radially outward with the tissue.

20. The cannula set forth in claim 19 wherein the annular distal end of the outer sleeve is tapered for less obtrusive penetration by the cannula into the tissue.

21. The cannula set forth in claim 18 wherein the insulating outer sleeve has an outer diameter of sixteen gauge or less.

22. A method of operating a bipolar electrosurgical system comprising the steps of:

penetrating tissue with a pointed tubular body of a cannula;

locating the body to targeted tissue;

inserting a supply electrode of a supply electrode assembly in a through-bore of the body;

making electrical contact between a shell of the supply electrode and a first electrode of the cannula that is exposed at least in part to the targeted tissue;

further inserting the supply electrode into the through-bore; and

making electrical contact between a first terminal supported by a first coupling assembly of the cannula and a second terminal supported by a second coupling assembly of the supply electrode assembly.