Patent ID: 8406900

Claim:
An implantable lead having a proximal end and a distal end, comprising: a conductor having a proximal end and a distal end; and an electrode assembly, arranged at the distal end of the lead, and comprising: a housing defining an internal cavity and having a proximal end and a distal end a helical guide spring arranged in a proximal portion of the cavity and having several spaced turns; and a fixation assembly, which is rotatable relative to the housing, the fixation assembly comprising; a shaft, the shaft extending into the cavity from the proximal end of the housing, and an extendable helical fixation element attached to the shaft at the distal end thereof and protruding beyond the distal end thereof; wherein the fixation assembly has an interaction portion and said guide spring being in mechanical connection with said housing at at least one of said ends of said housing to cause the interaction portion of the fixation assembly to extend into a space between, and slide against, the adjacent turns of the helical guide spring to longitudinally move the fixation assembly, when the shaft is rotated.