System, method and apparatus for electrosurgical instrument with movable fluid delivery sheath

• US 8,323,279 B2
• Filed: 09/25/2009
• Issued: 12/04/2012
• Est. Priority Date: 09/25/2009
• Status: Active Grant

• Current Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Original Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Inventors: Dahla, Robert H., Gutierrez, Irma
• Primary Examiner(s): Dvorak, Linda
• Assistant Examiner(s): DELLA, JAYMI E
• Application Number:
  US12/566,946
• Publication Number:
  US 20110077646A1
• Time in Patent Office: 1,166 Days
• Field of Search: 606/48, 606/50, 604/33, 604/27, 604/35, 604/158, 604/163, 604/164.02, 604/181, 604/183, 604118-121, 604/30, 604/40, 604/508, 251/267
• US Class Current: 606/48
• CPC Class Codes: A61B 18/1402 Probes for open surgery
• CPC Class Codes: A61B 2018/00583 Coblation, i.e. ablation using a cold plasma
• CPC Class Codes: A61B 2018/1472 for use with liquid electrolyte, e.g. virtual electrodes

Abstract

An electrosurgical instrument with a movable fluid delivery sheath assembly for variable fluid supply during surgical procedures is disclosed. The instrument comprises at least one active electrode and at least one return electrode, positioned on the instrument distal end. The sheath assembly has an outer sheath that is external to the instrument shaft, to provide a lumen. The sheath assembly lumen is axially movable between first and second positions relative to a fluid delivery element, for varying target site treatment and fluid delivery. In the first position the shaft distal end is axially distal to a leading edge of the sheath assembly. In the second position the sheath assembly distal leading edge is positioned axially adjacent or distal to the end of the shaft. The fluid delivery element comprises an inner lumen extending through at least a portion of the shaft, and at least one port extending radially through the shaft. The port is in communication with the inner lumen. A fluid supply source provides fluid through the port, sheath lumen and inner lumen.

Claims

1. A system for treating tissue, comprising:

an electrosurgical instrument having a shaft with a proximal end and a distal end portion;

an electrode assembly positioned on the distal end portion of the shaft comprising at least one active electrode and at least one return electrode axially spaced from the at least one active electrode;

a fluid delivery element for delivering electrically conductive fluid to the active electrode comprising an inner lumen extending through a portion of the shaft, and first and second ports extending radially through the shaft in fluid communication with the inner lumen; and

a sheath assembly disposed adjacently to the fluid delivery element and comprising at least one radial seal to sealingly engage the shaft and the sheath assembly, the sheath assembly being axially moveable relative to the fluid delivery element from a first position to a second position;

wherein the fluid delivery element further comprises a fluid source connected to the sheath assembly proximal to the at least one radial seal and, when the sheath assembly is in the second position, the fluid source flows through a sequential fluid delivery path, through the sheath assembly proximal to the at least one radial seal, the first port, the inner lumen, the second port, the sheath assembly that is distal to the radial seal and via a distal opening disposed adjacent the electrode assembly.

2. A system according to claim 1, wherein a distal leading edge of the sheath assembly is spaced axially proximal from the distal end portion of the shaft when the sheath assembly is in the first position, and the distal leading edge of the sheath assembly is disposed substantially axially adjacent to the distal end portion of the shaft when the sheath assembly is in the second position.

3. A system according to claim 1, wherein the first port comprises a plurality of ports that are located axially adjacent the distal end portion of the shaft and axially spaced from the electrode assembly.

4. A system according to claim 1, wherein the sheath assembly comprises a tube that is slidably movable relative to and concentric with the shaft, the tube defining an outer lumen between the tube and the shaft and the at least one radial seal being disposed between an outer surface of the shaft and an inner surface of the tube and sealingly engaging the shaft and the tube.

5. A system according to claim 4, wherein the at least one radial seal comprises a plurality of o-rings that are seated in an axial series of radial grooves formed in the inner surface of the tube, the radial grooves being axially spaced from each other.

6. A system according to claim 1, the first position operable to deliver fluid at a distance spaced away from the electrode assembly and the second position operable to deliver fluid adjacent to the active electrode.

7. A system according to claim 1, wherein the sheath assembly has a range of motion between the first and second positions that provides a variable level of fluid delivery, from a minimal level of fluid delivery in the first position, to a maximum level of fluid delivery in the second position.

9. A system according to claim 1, wherein the first and second ports each comprise a plurality of ports, with the second port being located adjacent the distal end portion of the shaft and axially spaced from the electrode assembly, and the first port being located proximal to the second port.

10. A system according to claim 1, wherein the electrode assembly comprises an ablation electrode and a coagulation electrode, wherein the ablation electrode and the coagulation electrode are spaced axially from the return electrode.

8. A system for treating tissue, comprising:

an electrosurgical instrument having a shaft with a proximal end and a distal end portion;

an electrode assembly positioned on the distal end portion of the shaft comprising at least one active electrode and at least one return electrode axially spaced from the at least one active electrode;

a fluid delivery element for delivering electrically conductive fluid to the active electrode; and

a sheath assembly disposed adjacently to the fluid delivery element, the sheath assembly being axially moveable relative to the fluid delivery element from a first position to a second position;

wherein the fluid delivery element comprises an inner lumen extending through a portion of the shaft, and first and second ports extending radially through the shaft in fluid communication with the inner lumen, the first and second ports axially spaced apart; and

wherein the sheath assembly comprises a tube that is slidably movable relative to and concentric with the shaft, the tube defining an outer lumen between the tube and the shaft and having at least one radial seal, the at least one radial seal being disposed in the outer lumen between an outer surface of the shaft and an inner surface of the tube and sealingly engaging the shaft and the tube;

and further comprising a fluid source connected to the outer lumen proximal to the radial seal and, when the sheath assembly is in the second position, the fluid source provides a sequential fluid delivery path through the outer lumen proximal to the radial seal, the first port, the inner lumen, the second port, the outer lumen that is distal to the radial seal and via a distal opening disposed at the distal end of the shaft.

11. An electrosurgical instrument for removing tissue from a target site within or on a patient'"'"'s body comprising:

a shaft having proximal and distal end portion;

an electrode assembly comprising at least one active electrode positioned on the distal end portion of the shaft and a return electrode positioned on the shaft and axially spaced from the at least one active electrode;

a fluid delivery element for delivering fluid to the target site, the fluid delivery element comprising an inner lumen disposed along a portion of the shaft and a first and second plurality of orts extending radially through the shaft, the plurality of ports in fluid communication with the inner lumen;

a movable sheath assembly disposed adjacent to the shaft and defining an annular space around the shaft, the annular space having at least one radial seal disposed therein, the sheath assembly having a leading edge and being movable from a first position wherein the leading edge is retracted proximally from the electrode assembly to a second position wherein the leading edge is adjacent to the electrode assembly;

wherein the first and second plurality of ports are fluidly bypassed in the first position.

12. The electrosurgical instrument of claim 11, wherein the sheath assembly comprises a tube that is slidably movable relative to and concentric with the shaft, the tube defining an outer lumen between the tube and the shaft, the at least one radial seal being disposed between an outer surface of the shaft and an inner surface of the tube and sealingly engaging the shaft and the tube.

14. A system according to claim 11, wherein the electrode assembly comprises at least one ablation electrode and at least one coagulation electrode located on the shaft, wherein the ablation electrode and the coagulation electrode are axially spaced from the return electrode.

15. A system according to claim 11, wherein the sheath assembly further comprises a grip operable to slide the sheath assembly into position.

13. An electrosurgical instrument for removing tissue from a target site within or on a patient'"'"'s body comprising:

a shaft having proximal and distal end portions;

an electrode assembly comprising at least one active electrode positioned on the distal end portion of the shaft and a return electrode positioned on the shaft and axially spaced from the at least one active electrode;

a movable sheath assembly disposed adjacent to the shaft and defining an annular space around the shaft, the sheath assembly having a leading edge and being movable from a first position wherein the leading edge is retracted proximally from the electrode assembly to a second position wherein the leading edge is adjacent to the electrode assembly, wherein the sheath assembly comprises a tube that is slidably movable relative to and concentric with the shaft, the tube defining an outer lumen between the tube and the shaft and having at least one radial seal, the at least one radial seal being disposed between an outer surface of the shaft and an inner surface of the tube and sealingly engaging the shaft and the tube;

a fluid delivery element for delivering fluid to the target site;

said delivery element comprising an inner lumen disposed along a portion of the shaft and a plurality of ports extending radially through the shaft, the plurality of ports in fluid communication with the inner lumen and the annular space;

wherein the first and second plurality of ports are fluidly bypassed in the first position, and wherein the first and second plurality of ports are fluidly connected to the outer lumen proximal to at least one radial seal in the second position.