Anchor sleeve for implantable lead

An anchor sleeve for securing a therapy delivery element, such as a stimulation lead or catheter, within a living body, that includes an inner sleeve with pre-formed locations of weakness that facilitate localized deformation. The anchor includes a deformable outer sleeve with a primary lumen extending along an axis. The outer surface of the outer sleeve includes a plurality of suture grooves oriented generally concentric to the axis. The inner sleeve includes a plurality of beams connected at deflection regions arranged around a secondary lumen. The inner sleeve is located in the primary lumen adjacent to the suture grooves so that the secondary lumen is generally concentric with the primary lumen. A plurality of locations of weakness are preformed in each of the beams to facilitate localized deformation in response to a radially inward force applied around the suture grooves by a suture material.