Resecting loop electrode and method for electrosurgical cutting and ablation
First Claim
1. An electrosurgical resecting instrument comprising:
- a shaft having a proximal end and a distal end;
at least one active electrode having an elongate body with first and second ends disposed near the distal end of the shaft, the elongate body having an active portion with a surface geometry configured to promote substantially high electric field intensities between the active portion and the target site when a high frequency voltage is applied to the electrode, wherein the electric field intensities are sufficient to vaporize an electrically conducting fluid in contact with the active portion of the electrode; and
a connector disposed near the proximal end of the shaft for electrically coupling the electrode to a high frequency voltage source.
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Accused Products
Abstract
An electrosurgical resecting instrument is provided having a resecting loop electrode on the distal end of a shaft and coupled to a high frequency voltage source. The loop electrode is configured to fit within a working end of a resectoscope (discussed below) and to remove small portions of tissue (e.g., chips of tissue). The loop electrode includes an active portion with a surface geometry configured to promote substantially high electric field intensities and associated current densities between the active portion and the target site when a high frequency voltage is applied to the electrode. The edges of the electrode are oriented substantially parallel to the shaft so that they will face the tissue as the electrode is moved axially in the cutting direction. This orientation facilitates formation of the vapor layer between the electrode edges and the tissue. The opposite or non-active side of the electrode may include an insulating layer to selectively reduce undesirable current flow from the non-active portion into tissue or surrounding electrically conducting liquids.
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Citations
51 Claims
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1. An electrosurgical resecting instrument comprising:
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a shaft having a proximal end and a distal end; at least one active electrode having an elongate body with first and second ends disposed near the distal end of the shaft, the elongate body having an active portion with a surface geometry configured to promote substantially high electric field intensities between the active portion and the target site when a high frequency voltage is applied to the electrode, wherein the electric field intensities are sufficient to vaporize an electrically conducting fluid in contact with the active portion of the electrode; and a connector disposed near the proximal end of the shaft for electrically coupling the electrode to a high frequency voltage source. - View Dependent Claims (2, 3, 4, 5, 6, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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7. An electrosurgical resecting instrument comprising:
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a shaft having a proximal end and a distal end; at least one active electrode having an elongate body with first and second ends disposed near the distal end of the shaft wherein the active electrode comprises a loop electrode having a semi-circular shape and being formed from a shaped wire having a non-circular, transverse cross-sectional shape; and a connector disposed near the proximal end of the shaft for electrically coupling the electrode to a high frequency voltage source.
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20. An electrosurgical resecting instrument comprising:
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a shaft having a proximal end and a distal end; at least one loop electrode having first and second ends and an elongate body therebetween, the first and second ends being disposed near the distal end of the shaft, the elongate body defining an obtuse angle with the shaft; and a connector disposed near the proximal end of the shaft for electrically coupling the electrode to a high frequency voltage source. - View Dependent Claims (21, 22, 23, 24, 25, 26)
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27. An electrosurgical system for use with a high frequency power supply, the system comprising:
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an electrosurgical resecting instrument comprising a shaft having a proximal end and a distal end, an active electrode having an elongate body with first and second ends disposed near the distal end of the shaft, and a connector near the proximal end of the shaft for electrically coupling the active electrode to the electrosurgical power supply; an electrically conducting outer sheath circumscribing the shaft and being adapted for electrical coupling to the electrosurgical power supply, the electrically conducting outer sheath having inner and outer surfaces and a distal end portion spaced proximal from the active electrode; and an insulating layer covering the inner and outer surfaces of the outer sheath, the insulating layer exposing the distal end portion of the outer sheath such that, when a voltage difference is applied between the distal end portion and the active electrode, electrical current flows between the active electrode and the distal end portion. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 37, 42)
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- 35. The system of claim 35 wherein the active electrode is formed from a hollow tube such that the elongate body has a semi-annular cross-section with first and second ends and an inner slot therebetween, the first and second ends each having a pair of edges for promoting localized high electric field intensities near the edges.
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38. A method for resecting tissue at a target site within a patient'"'"'s body, the method comprising:
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positioning a loop electrode and a return electrode into at least close proximity with the target site in the presence of electrically conductive fluid; applying high frequency voltage to the loop electrode and the return electrode such that an electrical current flows from the loop electrode, through the electrically conductive fluid, and to the return electrode; and translating the loop electrode to resect or ablate a portion of the tissue. - View Dependent Claims (39, 40, 41, 43, 44, 45, 46, 47, 48, 49, 50, 51)
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Specification