Patent ID: 8262574

Claim:
A needle electrode deployment shaft comprising: a central member having a proximal end, a distal end, a longitudinal axis therebetween, an outer surface, and a plurality of needle electrode advancement channels, each channel having an axially aligned proximal portion and an outwardly directed distal ramp portion; and a plurality of peripheral needle electrodes having tissue penetrating tips slidably received in said channels; wherein each proximal portion of each channel is straight and wherein each ramp portion of each channel follows a spiral path relative to the longitudinal axis and has (1) a ramp entrance located at a first angular orientation relative to the longitudinal axis and at a preselected radial distance between the longitudinal axis of the central member and the ramp entrance and (2) a ramp exit located at a second angular orientation angularly offset from the first angular orientation and on an outer surface of the central member.