Electrosurgical instrument

Patent metadata

Field	Value
Publication number	US-2021307820-A1
Application number	US-202117349356-A
Country	US
Kind code	A1
Filing date	Jun 16, 2021
Priority date	Oct 19, 2015
Publication date	Oct 7, 2021
Grant date	—

Abstract

Electrical instrument for applying radiofrequency and/or microwave frequency energy to tissue, comprising: a distal part comprising an instrument tip for applying radiofrequency and/or microwave frequency energy to tissue, the instrument tip comprising first and second conductive elements; a coaxial feed cable comprising an inner conductor, a tubular outer conductor coaxial with the inner conductor, and dielectric material separating the inner and outer conductors, the coaxial feed cable being for conveying radiofrequency and/or microwave frequency energy to the distal part; wherein: the inner conductor is electrically connected to the first conductive element and the outer conductor is electrically connected to the second conductive element through a rotatable connection between the distal part and the coaxial feed cable that allows rotation of the distal part relative to the coaxial feed cable; and the instrument comprises an actuator for rotating the distal part in a first rotational direction relative to the feed cable.

First claim

1 .- 50 . (canceled)

51 . An electrosurgical instrument for applying radiofrequency energy and/or microwave frequency energy to biological tissue, the instrument comprising:
a distal part comprising an instrument tip for applying radiofrequency energy and/or microwave frequency energy to biological tissue, wherein the instrument tip comprises a first conductive element and a second conductive element; a coaxial feed cable comprising an inner conductor, a tubular outer conductor coaxial with the inner conductor, and a dielectric material separating the inner and outer conductors, the coaxial feed cable being for conveying radiofrequency energy and/or microwave frequency energy to the distal part; wherein: the inner conductor is electrically connected to the first conductive element and the outer conductor is electrically connected to the second conductive element through a rotatable connection between the distal part and the coaxial feed cable that allows rotation of the distal part relative to the coaxial feed cable about a central axis of the distal part; the instrument comprises an actuator for rotating the distal part in a first rotational direction relative to the coaxial feed cable; and the rotatable connection comprises a flexible transmission line, the flexible transmission line having a first conductive path electrically connecting the inner conductor to the first conductive element and a second conductive path electrically connecting the outer conductor to the second conductive element.

52 . The electrosurgical instrument according to claim 51 , wherein the flexible transmission comprises a flexible strip.

53 . The electrosurgical instrument according to claim 52 , wherein the flexible transmission line is elastically resilient.

54 . The electrosurgical instrument according claim 51 , wherein:
the flexible transmission line comprises a flexible microwave substrate having a first conductive path on a first surface thereof and a second conductive path on an opposite second surface thereof; the first conductive path electrically connects the inner conductor to the first conductive element; and the second conductive path electrically connects the outer conductor to the second conductive element.

55 . The electrosurgical instrument according to claim 54 , wherein:
a distal end of the inner conductor protrudes from a distal end of the coaxial feed cable; and the first conductive path is connected to the protruding distal end of the inner conductor.

56 . The electrosurgical instrument according to claim 54 , wherein:
the flexible microwave substrate is a laminate structure comprising two layers laminated together; and the two layers are delaminated at a distal end of the flexible microwave substrate to form a first layer having the first conductive path and a second layer having the second conductive path.

57 . The electrosurgical instrument according to claim 54 , wherein:
the first conductive path is connected to the first conductive element on a first surface of the instrument tip; and the second conductive path is connected to the second conductive element on an opposite second surface of the instrument tip.

58 . The electrosurgical instrument according to claim 51 , wherein:
the instrument comprises an actuator element for rotating the distal part relative to the coaxial feed cable; the actuator element is configured to be moved axially along the instrument; and the distal part comprises an interface for converting axial movement of the actuator element into rotational movement of the distal part.

59 . The electrosurgical instrument according to claim 51 , wherein the instrument tip comprises a planar body made of a dielectric material separating the first conductive element on a first surface thereof from the second conductive element on a second surface thereof, the second surface facing in the opposite direction to the first surface.

60 . The electrosurgical instrument according to claim 59 , wherein:
the distal part further comprises a protective hull mounted to cover the underside of the planar body; the protective hull has a smoothly contoured convex under surface facing away from the planar body; the planar body has a tapering distal edge; and the underside of the planar body extends beyond the protective hull at the tapering distal edge.

61 . The electrosurgical instrument according to claim 51 , wherein a length of the instrument tip is substantially equal to

λ
2

,

where λ is the wavelength of microwave frequency energy having a predetermined frequency in the instrument tip.

62 . The electrosurgical instrument according to claim 51 , wherein:
a characteristic impedance of the instrument tip is substantially equal to a characteristic impedance of the coaxial feed cable; and the distal part comprises an impedance matching section for matching the characteristic impedance of the coaxial feed cable to the impedance of a tissue load in contact with the instrument tip at the predetermined frequency of microwave frequency energy, wherein the impedance matching section comprises:
a length of coaxial transmission line connected to a proximal end of the instrument tip; and
a short circuited stub.

Assignees

• Creo Medical Ltd

Inventors

• Hancock Christopher
• Morris Steven
• Burn Patrick
• Turner Louis
• Ullrich George
• Webb David

Classifications

• A61B18/14 Primary

  Probes or electrodes therefor · CPC title

• A61B2017/0034

  adapted to be inserted through a working channel of an endoscope · CPC title

• A61B2018/1823

  Generators therefor · CPC title

• A61B2018/00755

  Resistance or impedance · CPC title

• A61B2090/035

  preventing further rotation · CPC title