Solid-state deformation processing of crosslinked high molecular weight polymers such as UHMWPE, for example by extrusion below the melt transition, produces materials with a combination of high tensile strength and high oxidative stability. A command point sequence is divided into a plurality of segments and a segment curve corresponding to each segment command point sequence is created. The ramp has magnetic disk retainers each having slide surfaces and counter surfaces respectively facing the recording surfaces of the magnetic disk. A terminal portion of a final revolution of the distal portion has less curvature than previous portions of the distal portion for anchoring to an anatomical cavity lining of an anatomical cavity. The rigid outer tube supports the smaller flexible inner tube and allows a user to easily grasp the invention during use.