Patent ID: 7569053

Claim:
Apparatus for retrieving a tissue volume, comprising: a delivery assembly with a delivery member having a member exterior surface surmounting an interior channel assembly extending from a proximal portion along an axis to a forward region having a distal end supporting an electrically insulative heat resistant forward surface and said member exhibiting a member widthwise extent; a capture component positioned at said delivery member forward region, having a forward portion extending to a forwardly disposed tip region with a pursing cable assembly energizable to define an electrosurgical cutting leading portion, said cable assembly including tensionable cables extending from said forward portion at a deployment location thence along said interior channel assembly to a cable terminator, said forward portion being drivably extendable from an initial position, wherein portions of said cables extend about said member exterior surface at said deployment location, outwardly from said exterior surface and forwardly at a tip region angle of attack, while creating an electrosurgical arc, toward an intermediate position while drawing said cables along a laterally outwardly expanding locus of travel, said electrosurgical cutting leading portion defining a cutting profile of maximum effective diametric extent in correspondence with said intermediate position, and subsequently being drivably extendable while being drawn in contraction toward said axis at tip region inwardly directed pursing angles of attack by pursing stress at said cable assembly to a capture position; a precursor assembly comprised of two or more straight electrosurgical electrodes, each extending generally normally to and from the vicinity of said longitudinal axis to an electrode tip located a distance from said axis less than one-half said member widthwise extent and spaced axially forwardly from said portions of cables a distance, x, effective to avoid arc-over from said electrosurgical electrodes to said positions of cables extending about said member exterior surface when said precursor assembly is electrosurgically excited and said pursing cable assembly is not electrosurgically excited; and a control assembly actuatable to energize and de-energize said precursor electrodes having a drive portion in driving engagement with said capture component and actuatable to drive said capture component forward portion from said initial position into said capture position while effecting the electrosurgical energization thereof and de-energization of said pursing cable assembly.