In an implantable medical device, a locking mechanism with enhanced frictional stabilization comprises a substantially spherical elongating spring adapted to expand from a collapsed state to an elongated state, wherein the spring volume is increased in the elongated state for increasing a frictional contact with a surrounding surface. A screw or other protruding element is inserted into the spherical elongating spring for driving the expansion thereof. Locking methods include the expansion of a spring within an aperture of a device body for increasing frictional stabilization therein.
