| CPC A61B 18/1477 (2013.01) [A61B 2018/00601 (2013.01); A61B 2018/1427 (2013.01); A61B 2018/1475 (2013.01)] | 20 Claims |

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1. An instrument, comprising:
a sheath having a distal end;
a fluid cannula at the distal end of the sheath; and
a cutting electrode at the distal end of the sheath, wherein at least one of: (i) an exterior surface of the fluid cannula, or (ii) a cutting electrode surface that faces the exterior surface, is longitudinally slidable along the other of the exterior surface and the cutting electrode surface during movement of at least one of the cutting electrode or the fluid cannula relative to the other of the cutting electrode and the fluid cannula, wherein the fluid cannula includes an enlarged distal portion at a distal end of a tubular portion of the fluid cannula, wherein the enlarged distal portion is wider than the tubular portion, and wherein a distal end of the enlarged distal portion includes a sharpened tip,
wherein the fluid cannula and the cutting electrode are movable from a first configuration, in which the fluid cannula and the cutting electrode are independently movable, to a second configuration, in which the fluid cannula and the cutting electrode are coupled so as to move in unison,
wherein the cutting electrode includes a protrusion on a distal end of the cutting electrode,
wherein an entirety of the protrusion is non-conductive, and
wherein at least one of the cutting electrode or the fluid cannula is movable relative to the other of the cutting electrode and the fluid cannula between respective extended configurations and respective retracted configurations relative to the distal end of the sheath, wherein a distal portion of the protrusion includes a recess, and wherein (a) when the fluid cannula and the cutting electrode are in the retracted configurations, (1) a proximal face of the protrusion abuts a distal face of the sheath, (2) the recess receives at least a portion of the enlarged distal portion such that a proximal face of the enlarged distal portion abuts an annular distal face of the recess of the protrusion, and (3) the sharpened tip of the distal end of the fluid cannula extends distally of a distal end of the protrusion of the cutting electrode; and
and (b) when the fluid cannula and the cutting electrode are in the extended configurations (1) the recess receives at least a portion of the enlarged distal portion such that a proximal face of the enlarged distal portion abuts an annular distal face of the recess of the protrusion, and (2) the sharpened tip of the distal end of the fluid cannula extends distally of a distal end of the protrusion of the cutting electrode.
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