SYSTEM, METHOD AND APPARATUS FOR ELECTROSURGICAL INSTRUMENT WITH MOVABLE FLUID DELIVERY SHEATH

• US 20110077646A1
• Filed: 09/25/2009
• Published: 03/31/2011
• 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
• Granted Patent: US 8,323,279 B2
• Time in Patent Office: Days
• US Class Current: 606/50
• 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; 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.

2. A system according to claim 1, wherein the first position comprises positioning a distal leading edge of the sheath assembly axially proximal to the distal end portion of the shaft, and the second position comprises positioning the distal leading edge of the sheath assembly substantially axially adjacent to the distal end portion of the shaft.

3. A system according to claim 1, wherein the fluid delivery element comprises an inner lumen extending though at least a portion of the shaft and at least one port extending radially through the shaft, the at least one port in fluid communication with the inner lumen.

4. A system according to claim 3, further comprising a fluid source connected to the inner lumen for providing fluid though the at least one port and inner lumen.

5. A system according to claim 3, wherein the 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.

6. 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 having a radial seal, the 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.

7. A system according to claim 6, wherein the 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.

8. 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.

9. 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.

10. A system according to claim 1, 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.

11. A system according to claim 10, 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.

12. A system according to claim 10, wherein the first and second ports each comprise a plurality of ports, with the second ports being located adjacent the distal end portion of the shaft and axially spaced from the electrode assembly, and the first ports being located proximal to the second ports.

13. 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.

14. 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;

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.

15. The electrosurgical instrument of claim 14, 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.

16. The electrosurgical instrument of claim 14, wherein the fluid delivery element comprises:

an inner lumen disposed along a portion of the shaft; and

at least one port extending radially through the shaft, the at least one port in fluid communication with the inner lumen and the annular space.

17. The electrosurgical instrument of claim 16, the at least one port comprising a first and second plurality of ports, the first and second plurality of ports axially spaced apart.

18. The electrosurgical instrument of claim 17, 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.

19. A system according to claim 14, 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.

20. A system according to claim 14, wherein the sheath assembly further comprises a grip operable to slide the sheath assembly into position.

22. A method for treating tissue as in claim 20, further comprising positioning a first amount of fluid in the first position, and positioning a second amount a fluid in the second position, wherein the first amount is less than the second amount.

21. A method for treating tissue comprising:

positioning at least one active electrode adjacent to tissue;

positioning a sheath assembly in a first position, the first position creating a fluid delivery region proximal to the at least one active electrode;

delivering fluid to the region proximal to the at least one active electrode;

applying a first high frequency voltage between the at least one active electrode and a return electrode;

deploying the sheath assembly to a second position, the second position creating a fluid delivery region adjacent to the at least one active electrode; and

delivering fluid to the region adjacent to the at least one active electrode.

24. A method of claim 21 further comprising:

retracting the electrode assembly out of channel;

advancing the sheath assembly disposed adjacent to the fluid delivery element to the first position, wherein the first position defines an adjacent fluid delivery region; and

applying the first high frequency voltage between the first active electrode and the return electrode to ablate the surface of the tissue.

23. A method for creating a channel into tissue comprising:

positioning an electrode assembly comprising a first active electrode, a return electrode and a coagulation electrode adjacent to tissue;

positioning a sheath assembly disposed adjacent to a fluid delivery element in a first position, wherein the first position provides at least a portion of electrically conductive fluid at a position adjacent to the first active electrode;

applying a first high frequency voltage between the first active electrode and the return electrode;

during at least a portion of the applying step, advancing the active electrode into the tissue to generate space within the tissue while retracting the sheath assembly proximally to a second position, wherein the second position defines a proximal fluid delivery region; and

during or after the first applying step, applying a second high frequency voltage between the return electrode and the coagulation electrode, the second high frequency voltage insufficient to ablate the tissue.