Bipolar cannula for use with an electrode assembly having a separate supply electrode

• US 7,918,852 B2
• Filed: 05/01/2006
• Issued: 04/05/2011
• Est. Priority Date: 04/29/2005
• Status: Active Grant

• Current Assignee: Stryker Corporation
• Original Assignee: Stryker Corporation
• Inventors: Cramlet, Eland, Fickes, Nicole, Staats, Andy, Staunton, Douglas Alan, Gamhewage, Chamara, Tullis, Philip James
• Primary Examiner(s): Dvorak; Linda C
• Assistant Examiner(s): DELLA, JAYMI E
• Application Number:
  US11/381,064
• Publication Number:
  US 20070016185A1
• Time in Patent Office: 1,800 Days
• Field of Search: 606/48, 606/50, 606/41
• 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. A cannula for use with a console that generates an RF signal, said cannula including:

a hub formed from electrically insulating material shaped to be releasably coupled to a coupling member that extends from the console, said hub having a proximal end and defining;

a bore having an opening at said proximal end for receiving a supply electrode that extends forward from the console coupling member; and

an alcove that opens at said proximal end for receiving a terminal integral with the console coupling member, wherein said bore and said alcove are separated from one another;

an inner tube formed from electrically conductive material, said inner tube extending forward from said hub and having;

a through-bore coincidental with said hub bore and dimensioned to receive the supply electrode and dimensioned so that the supply electrode electrically connects to said inner tube when the supply electrode is received in said through-bore; and

a distal end that is spaced from said hub;

an inner sleeve formed from electrically insulating material that is disposed over said inner tube, said inner sleeve having a distal end that is spaced proximal to said distal end of said inner tube so that said distal end of said inner tube is exposed so as to function as a first active contact;

an outer tube formed from electrically conductive material disposed over said inner sleeve, said outer tube having a proximal end seated in said hub alcove and a distal end that is spaced from said hub;

an outer sleeve formed from electrically insulating material disposed over said outer tube, said outer sleeve having a distal end that is spaced proximal to said distal end of said outer tube so that said distal end of said outer tube is exposed so as to function as a second active contact; and

a conductive terminal that is mounted to said hub and that is positioned in said hub alcove so that when said hub is coupled to the console coupling member and the supply electrode is in said through-bore, the console coupling member terminal engages said conductive terminal and said conductive terminal is electrically connected to said outer tube.

2. The cannula as set forth in claim 1, wherein said conductive terminal is spring-loaded and configured to be biased resiliently against said conductive outer tube by the console coupling member terminal.

3. The cannula as set forth in claim 1, wherein said inner tube has an inner cylindrical surface around said through-bore configured for being in electrical contact with the supply electrode when the supply electrode is received in said through-bore.

4. The cannula of claim 1, wherein said electrically insulating material of said hub electrically separates said conductive terminal from said inner tube.

5. A cannula for use with a console that generates an RF signal, said cannula including:

a hub formed from electrically insulating material and having;

a proximal end;

a collar extending from said proximal end; and

a bore defined through said collar and dimensioned to releasably receive a post of a coupling member that extends from the console;

an inner tube formed from electrically conductive material, said inner tube extending forward from said hub and having;

a through-bore open to said hub bore and dimensioned to receive a supply electrode that extends forward from the console coupling member post and dimensioned so that the supply electrode electrically connects to said inner tube when the supply electrode is received in said through-bore and the console coupling member post is received in said hub bore; and

a distal end that is spaced from said hub;

said hub is formed so that as said hub bore extends distally toward said through-bore a diameter of said hub bore decreases for facilitating insertion of the supply electrode into said through-bore when mating the console coupling member with said cannula;

an inner sleeve formed from electrically insulating material that is disposed over said inner tube, said inner sleeve having a distal end that is spaced proximal to said distal end of said inner tube so that said distal end of said inner tube is exposed so as to function as a first active contact;

a second active contact that is disposed over said inner sleeve; and

a conductive terminal that is mounted to said hub and that is positioned so that when said hub is coupled to the console coupling member and the supply electrode is in said through-bore, a terminal integral with the console coupling member engages said conductive terminal and said conductive terminal is electrically connected to said second active contact.

6. The cannula as set forth in claim 5, wherein said inner tube has an inner cylindrical surface extending from said hub bore and configured for being in electrical contact with the supply electrode.

7. The cannula of claim 5, wherein said electrically insulating material of said hub electrically separates said conductive terminal from said inner tube.

8. The cannula of claim 5, including:

an outer tube formed from electrically conductive material disposed over said inner sleeve, said outer tube having a proximal end that is connected to said conductive terminal in said hub and a distal end located adjacent said distal end of said inner sleeve; and

an outer sleeve formed from electrically insulating material disposed over said outer tube so that that said distal end of said outer tube is exposed so as to function as said second active contact.