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EP-3629969-B1 - ELECTROSURGICAL INSTRUMENT FOR ABLATION AND RESECTION

EP3629969B1EP 3629969 B1EP3629969 B1EP 3629969B1EP-3629969-B1

Inventors

  • HANCOCK, CHRISTOPHER PAUL
  • WHITE, MALCOLM
  • BURN, Patrick
  • CLEGG, PETER

Dates

Publication Date
20260506
Application Date
20180601

Claims (7)

  1. An electrosurgical instrument for delivering radiofrequency (RF) electromagnetic (EM) energy and microwave EM (114) energy for resection and ablation of biological tissue, the instrument (100) comprising: a coaxial transmission line for conveying the RF EM energy and the microwave EM (114) energy, the coaxial transmission line comprising an inner conductive layer (104), an outer conductive layer (106) and a dielectric layer (108) separating the inner conductive layer (104) from the outer conductive layer (106); characterized by a ball-shaped instrument tip (200) at a distal end of the energy conveying cable structure, the instrument tip (200) comprising: a first conductive hemisphere (202) electrically connected to the inner conductive layer (104); a second conductive hemisphere (204) electrically connected to the outer conductive layer (106); and a planar dielectric layer (206) located in a physical separation gap between the first conductive hemisphere (202) and the second conductive hemisphere (204), wherein the first conductive hemisphere (202) and the second conductive hemisphere (204) are configured to: radiate the microwave EM (114) energy as a substantially spherical field, and provide respectively an active electrode (208) and a return electrode (210) on opposing sides of the separation gap for delivering the RF EM energy.
  2. An electrosurgical instrument according to claim 1, wherein the ball-shaped instrument tip (200) has a diameter equal to or less than 3 mm.
  3. An electrosurgical instrument according to claim 1 or 2, wherein the first conductive hemisphere (202) and the second conductive hemisphere (204) are symmetrically mounted on the planar dielectric layer (206).
  4. An electrosurgical instrument according to any one of claims 1 to 3 including: a first electrical connector mounted on a first surface of the planar dielectric layer (206), the first electrical connector electrically connecting the inner conductive layer (104) to the first conductive hemisphere (202); and a second electrical connector mounted on a second surface of the planar dielectric layer (206) opposite to the first surface, the second electrical connector electrically connecting the outer conductive layer (106) to the second conductive hemisphere (204).
  5. An electrosurgical instrument according to any one of claims 1 to 4, wherein the coaxial transmission line includes a fluid flow passage for conveying a fluid to the instrument tip (200).
  6. An electrosurgical instrument according to claim 5, wherein the instrument tip (200) includes a fluid flow outlet (212) connected to the fluid flow passage.
  7. An electrosurgical instrument according to claim 6, wherein the fluid passage is through the planar dielectric layer (206).

Description

FIELD OF THE INVENTION The invention relates to a combined ablation and resection instrument, and an energy delivery system to enable ablation and resection by the instrument. BACKGROUND TO THE INVENTION Surgical resection is a means of removing sections of unwanted tissue associated with organs within the human or animal body, such as the liver or the spleen or the bowel. When tissue is cut (divided or transected) small blood vessels called arterioles are damaged or ruptured. Initial bleeding is followed by a coagulation cascade where the blood is turned into a clot in an attempt to plug the bleeding point. During an operation, it is desirable for a patient to lose as little blood as possible, so various devices have been developed in an attempt to provide blood free cutting. For example, the Hemostatix® Thermal Scalpel System combines a sharp blade with a haemostatic system. The blade is coated with a plastic material and connected to a heating unit which accurately controls the temperature of the blade. The intention is for the heated blade to cauterise the tissue as it is cut. Other known devices that cut and stop bleeding at the same time do not use a blade. Some devices use radiofrequency (RF) energy to cut and/or coagulate tissue. Other devices (known as harmonic scalpels) use a rapidly vibrating tip to cut tissue. The method of cutting using RF energy operates using the principle that as an electric current passes through a tissue matrix (aided by the ionic contents of the cells), the impedance to the flow of electrons across the tissue generates heat. When a pure sine wave is applied to the tissue matrix, enough heat is generated within the cells to vaporise the water content of the tissue. There is thus a huge rise in the internal pressure of the cell that cannot be controlled by the cell membrane, resulting in the cell rupturing. When this occurs over a wide area it can be seen that tissue has been transected. RF coagulation operates by applying a less efficient waveform to the tissue, whereby instead of being vaporised, the cell contents are heated to around 65°C. This dries out the tissue by desiccation and also denatures the proteins in the walls of vessels and the collagen that makes up the cell wall. Denaturing the proteins acts as a stimulus to the coagulation cascade, so clotting is enhanced. At the same time the collagen in the wall is denatured from a rod like molecule to a coil, which causes the vessel to contract and reduce in size, giving the clot an anchor point, and a smaller area to plug. The application of heat energy to biological tissue is also an effective method of killing cells. For example, the application of microwaves can heat and thus ablate (destroy) biological tissue. This method may in particular be used for the treatment of cancer as the cancerous tissue can be ablated in this way. US 2013/289557 A1 discloses an electrosurgical instrument with dual radiofrequency and microwave electromagnetic energy. GB 2 531 434 A refers to a cable for conveying radiofrequency and/or microwave frequency energy to an electrosurgical instrument. US 2002/077626 A1 discloses a bipolar electrosurgical handpiece for treating tissue. WO 2015/066311 A1 refers to systems and methods for neuromodulation and treatment of abnormal growths. US 2010/004650 A1 refers to an angioplasty and tissue ablation apparatus and method. US 2017/014184 A1 discloses a surgical snare with the ability to deliver electromagnetic energy and/or thermal plasma into biological tissue. EP 2716251 A1 discloses a bipolar needle-shaped microwave surgical instrument. KR 20150001453 U discloses a disposable electrosurgical handpiece for treating tissue. SUMMARY OF THE INVENTION At its most general, the present invention provides an electrosurgical instrument which is capable of simultaneously ablating an area of tissue with microwave energy and performing resection with RF energy. In particular, the invention is concerned with structure for conveying both RF and microwave energy to an instrument tip that is configured to emit the microwave energy in a manner suitable for ablation (e.g. as a substantially spherical field) and to emit the RF energy in a more focussed manner to enable accurate and controllable resection to be performed. The invention is defined in claim 1 while the dependent claims describe preferred embodiments of the invention. According to an aspect, there is provided an electrosurgical instrument for delivering radiofrequency (RF) electromagnetic (EM) energy and microwave EM energy for resection and ablation of biological tissue, the instrument comprising: an energy conveying cable structure comprising: a coaxial transmission line for conveying microwave energy, the coaxial transmission line comprising an inner conductive layer, an outer conductive layer and a dielectric layer separating the inner conductive layer from the outer conductive layer, wherein the inner conductive layer is formed around a hollow