Electrosurgical resection instrument

Patent metadata

Field	Value
Publication number	US-10251697-B2
Application number	US-201314411327-A
Country	US
Kind code	B2
Filing date	Jun 25, 2013
Priority date	Jul 3, 2012
Publication date	Apr 9, 2019
Grant date	Apr 9, 2019

Abstract

An electrosurgical resection instrument for applying to biological tissue radiofrequency electromagnetic energy has a protective hull comprising a shaped piece of dielectric material mounted to cover an underside of an instrument tip of the instrument. The protective hull acts as a shield to protect tissue that may lie under the instrument tip from damage during treatment. The instrument may be particularly useful in procedures performed in a gastrointestinal tract, where bowel perforation is a concern, or in the pancreas, where damage to the portal vein or the pancreatic duct may occur when a tumor or other abnormality is being resected, dissected or removed.

First claim

The invention claimed is:

1. An electrosurgical resection instrument for applying to biological tissue radiofrequency (RF) electromagnetic (EM) energy, the instrument comprising:
an instrument tip comprising a planar body made of a first dielectric material separating a first conductive element on a first surface thereof from a second conductive element on a second surface thereof, the second surface facing in an opposite direction to the first surface;
a coaxial feed cable comprising an inner conductor, an outer conductor coaxial with the inner conductor and a second dielectric material separating the inner and outer conductors, the coaxial feed cable being for conveying an RF signal; and
a protective hull comprising a third piece of dielectric material mounted to form an underside of the instrument tip,
wherein the formed underside of the instrument tip further comprises a smoothly contoured convex undersurface facing away from the planar body of the instrument tip, and a pair of ridges extending in a direction away from the planar body of the instrument tip and forming a recessed channel parallel to and below the planar body of 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
characterised in that the first and second conductive elements extend up to a distal side edge of the planar body to form an RF cutting portion in which the first and second conductive elements act as active and return electrodes to emit RF EM radiation corresponding to the RF signal from the distal side edge of the planar body.

2. An instrument according to claim 1 , wherein the smoothly contoured convex undersurface of the protective hull smoothly tapers at a perimeter to meet the distal side edge of the planar body.

3. An instrument according to claim 1 , wherein thickness of the protective hull decreases towards the distal end of the instrument tip.

4. An instrument according to claim 1 , wherein separation of the first and second conductive elements at the distal side portion edge is less than 1 mm.

5. An instrument according to claim 1 , wherein the first and second conductive elements each comprise a layers of metallisation, the layers of metallisation being formed on opposite surfaces of the first dielectric material.

6. An instrument according to claim 5 , wherein layer of metallisation comprises a plated region formed from a metal having a melting point higher than 1500° C.

7. An instrument according to claim 6 , wherein the first conductive element comprises a first connecting portion between the plated region and the inner conductor and the second conductive element comprises a second connecting portion between the plated region and the outer conductor, wherein the first and second connecting portions are made from a conductive material having melting point less than 1200° C.

8. An instrument according to claim 1 , wherein the protective hull is formed from ceramic or biocompatible plastic.

9. An instrument according to claim 1 , wherein the protective hull and first dielectric material are formed in one piece as a unitary body.

10. An instrument according to claim 3 , wherein the instrument tip has a curved distal edge.

11. An instrument according to claim 1 including a fluid feed conduit for conveying fluid to the instrument tip for delivery out of the instrument.

12. An instrument according to claim 11 , wherein the fluid feed conduit comprises a sleeve that defines a lumen for transporting fluid to the instrument tip, the sleeve having the instrument tip body and protective hull secured at a distal end thereof, and being arranged to carry the coaxial cable in the lumen.

13. An instrument according to claim 12 including a fluid delivery mechanism mounted at the distal end of lumen of the sleeve, the fluid delivery mechanism being operable to deliver fluid from the lumen through the protective hull.

14. An instrument according to claim 13 , wherein the fluid delivery mechanism includes a retractable needle mounted beneath the planar body in the recessed channel of the protective hull.

15. An instrument according to claim 14 , wherein the retractable needle is movable in the longitudinal direction between a deployed position in which the retractable needle protrudes beyond the distal end of the instrument tip and a retracted position in which the retractable needle is set back from the distal edge of the instrument tip.

16. An instrument according to claim 12 , wherein the sleeve has longitudinal braids therein to assist in a transfer of torque from a proximal end to the instrument tip.

17. An instrument according to claim 12 , wherein the sleeve comprises a multi lumen tube.

18. An instrument according to claim 17 , wherein the sleeve includes an extruded separator element inserted inside a single lumen tube, the extruded separator element including a U-shaped channel for guiding the coaxial cable and one or more longitudinal passages for fluid to flow along the sleeve.

19. An instrument according to claim 12 , wherein sleeve has an outer diameter of 2.8 mm or less.

20. An instrument according to claim 12 including a element at the distal end of the sleeve, the cap element covering an electrical joint between the coaxial cable and the first and second conductive elements.

21. An instrument according to claim 12 wherein the cap element is formed from an impermeable insulating potting material.

22. An instrument according to claim 1 , wherein coaxial cable is arranged to convey a microwave signal separately from simultaneously with the RF signal, and wherein the first and second conductive elements are arranged on the first dielectric element to act as an antenna to radiate microwave EM radiation corresponding to the received microwave signal.

23. An instrument according to claim 1 for removing abnormalities from the lower and/or upper GI tracts.

24. An instrument according to claim 1 for performing resection or removal of tumours in close proximity to the portal vein or the pancreatic duct.

25. An instrument according to claim 23 , wherein the abnormalities are sessile polyps.

26. An instrument according to claim 6 , wherein the metal is at least one of titanium or tungsten.

27. An instrument according to claim 7 , wherein conductive material is at least one of silver or gold.

Assignees

• Creo Medical Ltd

Inventors

• Hancock Christopher Paul
• Morris Steven
• Fitzsimmons Duncan
• Saunders Brian
• Pacey Andrew
• White Malcolm

Classifications

• A61B2218/002

  Irrigation · CPC title

• A61B2018/1892

  Details of electrical isolations of the antenna · CPC title

• A61B2018/1876

  with multiple frequencies · CPC title

• A61B2018/1405

  Electrodes having a specific shape · CPC title

• A61B2018/128

  generating two or more frequencies · CPC title