An implantable tensile device and method of use thereof for flexibly securing skeletal parts. The device includes a planar tensile portion between fixation ends adapted to be fastened to skeletal parts. The tensile portion includes flexure slots extending from its sides beyond a longitudinal central axis to a terminal bottom. The flexure slots are keyhole shaped. The fixation ends are fastened to the skeletal parts with screw fasteners. The device can be fastened to the skeletal parts after pre-tensioning with an extension tool such that the skeletal parts to which the fixation ends are fastened are biased toward one another. Without pre-tensioning, the skeletal parts are flexibly secured and further expansion thereof is resisted. Abutment elements on the fixation ends are engaged by the extension tool for pre-tensioning.
