Electrosurgical instrument with dual radiofrequency and microwave electromagnetic energy

Patent metadata

Field	Value
Publication number	US-9636176-B2
Application number	US-201213997915-A
Country	US
Kind code	B2
Filing date	Jan 9, 2012
Priority date	Jan 11, 2011
Publication date	May 2, 2017
Grant date	May 2, 2017

Abstract

An electrosurgical instrument for delivering radiofrequency (RF) electromagnetic (EM) energy and microwave frequency EM energy from a coaxial feed cable through an instrument tip into tissue. The instrument tip comprises a dielectric body separating first and second conductive elements, which act as active and return electrodes to convey the RF EM radiation by conduction, and as an antenna to radiate the microwave EM radiation. The instrument also has a fluid feed incorporated into its tip, e.g. in an additional dielectric element mounted on the underside of the tip, for delivering fluid. The delivered fluid may be a gas plasma to assist treatment or a liquid to plump up a tissue region before treatment. The instrument may fit in an endoscope.

First claim

The invention claimed is:

1. An electrosurgical resection instrument for applying to biological tissue radiofrequency (RF) electromagnetic (EM) energy having a first frequency and microwave EM energy having a second frequency higher than the first frequency, the instrument comprising:
an instrument tip comprising a body made of a first dielectric material separating a first conductive element from a second conductive element;
a coaxial feed cable comprising an inner conductor, an outer conductor coaxial with the inner conductor, and a second dielectric material separating the outer conductor and the inner conductor, the coaxial feed cable being for conveying, simultaneously or separately, an RF signal having the first frequency and a microwave signal having the second frequency;
a fluid feed conduit for delivering fluid to the instrument tip;
wherein the inner conductor is electrically connected to the first conductive element and the outer conductor is electrically connected to the second conductive element to enable the instrument tip to receive the RF signal and the microwave signal, and
wherein the first conductive element and the second conductive element are arranged to act:
as an active electrode and a return electrode to convey RF EM radiation corresponding to the RF signal, and
as an antenna to radiate microwave EM radiation corresponding to the microwave signal,

wherein the fluid feed conduit is arranged to deliver liquid to the instrument tip, the fluid feed conduit having an outlet at the distal end of the instrument tip for introducing the liquid into the biological tissue,
wherein the instrument tip further comprises a planar transmission line element in which the body of the first dielectric material is a substantially planar element, the first conductive element is a first conductive layer on a first surface of the substantial planar element, and the second conductive element is a second conductive layer on a second surface of the substantial planar element that is opposite to the first surface, and
wherein the first surface of the substantially planar element and the second surface of the sustainably planer element extend between the first conductive element and the second conductive element in a direction parallel to a longitudinal axis of the coaxial feed cable;
wherein both the first conductive layer and the second conductive layer extend up to at least one edge of the planer element in a region designated as an RF cutting portion, and are set back from the edges of the planer element except at the RF cutting portion; and
wherein the instrument further comprises a common carrier tube for conveying the fluid flow conduit and the coaxial cable together to the instrument tip body.

2. The instrument according to claim 1 , wherein both the first conductive element and the second conductive element extend to one or both edges of the first dielectric material.

3. The instrument according to claim 1 , wherein the distal end of the first dielectric material is rounded.

4. The instrument according to claim 1 , wherein the fluid feed conduit is arranged to deliver liquid saline to the instrument tip.

5. The instrument according to claim 1 comprising a third dielectric material mounted on the underside of the instrument tip body, the third dielectric member curving upwards along its length towards the instrument tip.

6. The instrument according to claim 5 , wherein the third dielectric material includes a longitudinal passage for receiving the fluid feed conduit.

7. The instrument according to claim 1 , wherein the fluid feed conduit comprises a tip section movable in a longitudinal direction relative to the instrument tip body between an extended position in which the outlet is located at the distal tip of the instrument, and a retracted position in which the outlet is set back from the distal tip of the instrument.

8. The instrument according to claim 7 , wherein the tip section comprises a needle.

9. The instrument according to claim 1 , wherein the common carrier tube has an outside diameter of less than 2.5 mm.

10. The instrument according to claim 9 , wherein the common carrier tube comprises a first longitudinal bore for receiving the coaxial cable and a second longitudinal bore for receiving the fluid flow conduit.

11. The instrument according to claim 9 comprising a rotation knob secured to the common carrier tube for rotating the common carrier tube in an instrument channel of an endoscope.

12. The instrument according to claim 1 , wherein the fluid feed conduit is arranged to deliver gas into a plasma generation region located between the first and second conductive elements in the instrument tip, and wherein the first conductive element and the second conductive element are configured to create an electric field from the received RF signal or the microwave signal that is capable of ionising the gas to generate a thermal or non-thermal plasma.

13. The instrument according to claim 12 , wherein the plasma generation region either:
is enclosed within the instrument tip, the plasma being used to provide a local return path for the RF signal to facilitate cutting the biological tissue, or
includes an outlet for permitting non-thermal or thermal plasma to be delivered to the biological tissue.

14. The instrument according to claim 1 , wherein the coaxial feed cable and the fluid feed conduit have a combined diameter that is less than 2.5 mm, and the instrument tip extends out of the coaxial feed cable by 12 mm or less, and has a width of 2.0 mm or less and a thickness of 0.5 mm or less.

15. The instrument according to claim 1 , wherein the fluid feed conduit is arranged to deliver gas into a plasma generation region located between the first and second conductive elements in the instrument tip, and wherein the first conductive element and the second conductive element are configured to create an electric field from the received RF signal and the microwave signal that is capable of ionising the gas to generate a thermal or non-thermal plasma.

Assignees

• Hancock Christopher Paul
• Booton Martin Wynford
• Creo Medical Ltd

Inventors

• Hancock Christopher Paul
• Booton Martin Wynford

Classifications

• H01Q21/06

  Arrays of individually energised antenna units similarly polarised and spaced apart · CPC title

• H01Q13/08

  Radiating ends of two-conductor microwave transmission lines, e.g. of coaxial lines, of microstrip lines · CPC title

• A61B2018/1892

  Details of electrical isolations of the antenna · CPC title

• A61B2018/1876

  with multiple frequencies · CPC title

• H01Q1/36

  Structural form of radiating elements, e.g. cone, spiral, umbrella; {Particular materials used therewith}(H01Q1/08, H01Q1/14 take precedence) · CPC title