Flexible electrosurgical ablation and aspiration electrode with beveled active surface
Disclosed herein is a flexible single piece active element for use in connection with aspirating electrosurgical ablators, particularly those configured for bulk tissue vaporization. The active electrode elements of the present invention provide a simple construction suitable for use with a wide array of electrosurgical components and adjustable to wide range of angled positions to permit access to a variety of tissues, in an array of diverse environments and address a host of ablation needs. Additionally, the novel geometry and positioning of both ablation surface and aspiration ports permit aspiration flow to remove primarily waste heat rather than process heat, to thereby improve vaporization efficiency and reduce procedure time. Thus, active electrodes and ablation devices of the present invention maximize efficiency and adaptability while minimizing manufacturing cost and device profile.
1. An active electrode for connection to an electrosurgical device for the bulk vaporization of tissue, the electrosurgical device comprising an elongate cannulated tubular member having a proximal end, a distal end and a tubular lumen extending therebetween, wherein said active electrode is formed from a metallic material as a single, continuous homogenous element and comprises an open proximal end, a closed distal end and a central lumen extending therebetween, and is further characterized by the following features:
a. a cylindrical distal portion having a longitudinal axis, an outer diameter, and an inner diameter and a beveled distal-most ablation surface that forms an acute angle with said longitudinal axis of said cylindrical distal portion,
b. a raised flange portion proximally adjacent to said cylindrical distal portion having a outer diameter greater than the outer diameter of said cylindrical distal portion and a distal-facing surface that projects in a direction transverse to said longitudinal axis so as to serve as an insulator stop,
c. a cylindrical middle portion proximally adjacent to said flange portion comprising a longitudinal axis, an outer diameter, and an inner diameter, wherein said cylindrical middle portion and said cylindrical distal portion are not coaxial, further wherein the longitudinal axis of the cylindrical middle portion forms a pre-determined acute angle with the longitudinal axis of said cylindrical distal portion,
d. a cylindrical proximal portion configured for attachment to the elongate cannulated tubular member of said electrosurgical device, and
e. a lateral opening formed in a side wall of said cylindrical distal portion and positioned fully proximal to the entirety of said beveled distal-most ablation surface, said opening extending through the side wall of said distal portion into said central lumen.
2. The active electrode of claim 1 in which said lateral opening is immediately adjacent to said beveled distal-most ablation surface.
3. The active electrode of claim 1 in which said lateral opening is displaced proximally a predetermined distance from said beveled distal-most ablation surface.
4. The active electrode of claim 1 , wherein said beveled distal-most ablation surface is configured with machined contours.
5. The active electrode of claim 4 , wherein said machined contours comprise a series of parallel grooves.
6. The active electrode of claim 4 , wherein said machined contours comprise an array of protruding pins.
7. The active electrode of claim 4 , wherein said machined contours comprise an array of raised ribs.
8. An electrosurgical assembly for the bulk vaporization of tissue comprising:
a. the active electrode of claim 1 ;
b. a cylindrical insulator formed from a suitable dielectric material having an open proximal end characterized by a first proximal-most surface and an open distal end characterized by a second distal-most surface, wherein said insulator is positioned about the cylindrical distal portion of said active electrode such that the first proximal-most surface of said insulator abuts the distal-facing surface of said flange portion, and said second distal-most surface of said insulator is slightly proximal to said beveled ablation surface of said active electrode, and
c. an elongate cannulated tubular element affixed to the cylindrical proximal portion of said active electrode, and
d. an optional dielectric coating covering the exterior of the elongate cannulated tubular element, the portion of the active electrode proximal to said insulator, and a proximal portion of said insulator,
wherein said lateral opening, said active electrode central lumen, and the cannulated tubular element provide a continuous aspiration path allowing the flow of vaporization by-products from the region adjacent to the beveled ablation surface and to the proximal end of the elongate cannulated tubular element.
9. The electrosurgical device of claim 8 , wherein said cylindrical middle portion is provided with an area of reduced wall thickness that affords flexibility to said active electrode, permitting the formation of said pre-determined acute angle with the longitudinal axis of said cylindrical distal portion.
10. The electrosurgical device of claim 8 , wherein said lateral opening comprises an aspiration port configured to remove byproducts of ablation from the region surrounding said beveled distal-most ablation surface.
11. A method for forming the active electrode of claim 1 , said method comprising the steps of:
a. on a screw-machine, lathe or other suitable turning machine, forming a metal blank having (i) cylindrical distal portion of a predetermined length and outer diameter, (ii) a raised flange portion having an outer diameter greater than the outer diameter of said cylindrical distal portion and having a distal-facing surface, said flange portion being proximally adjacent to said cylindrical distal portion, (iii) a cylindrical middle portion proximal to said flange portion, (iv) a cylindrical proximal-most portion formed for attachment to an elongated cannulated member, and (v) a central lumen extending from the proximal end of said active electrode to a predetermined depth;
e. beveling the distal end of said blank to form an angled distal most surface on said blank;
f. forming a lateral opening between the exterior surface of said cylindrical distal portion and the central lumen, wherein said a lateral opening is fully proximal to the entirety of said angled distal-most ablation surface; and
g. bending the cylindrical middle portion a pre-determined acute angle such that cylindrical distal portion and said cylindrical middle portion are not coaxial to thereby give rise to the active electrode as set forth in claim 1 .
12. The method of claim 11 , further comprising the step of providing said cylindrical middle portion with an area of reduced wall thickness that affords flexibility to said active electrode, thereby enabling the bending of step (d).
13. The method of claim 11 , wherein said lateral opening comprises an aspiration port configured to remove byproducts of ablation from the region surrounding said beveled distal-most ablation surface.
14. The active electrode of claim 1 , wherein said cylindrical middle portion is provided with an area of reduced wall thickness that affords flexibility to said active electrode, permitting the formation of said pre-determined acute angle with the longitudinal axis of said cylindrical distal portion.
15. The active electrode of claim 1 , wherein said lateral opening comprises an aspiration port configured to remove byproducts of ablation from the region surrounding said beveled distal-most ablation surface.