An inter-level locking mechanism of a multi- level medical device is disclosed. The locking mechanism includes (a) an elongated element (100) having a plurality of flexing regions, wherein the elongated element assumes a straightened configuration for introduction into the body, and wherein the elongated element assumes a closed helix configuration with a first portion of the elongated element coming in overlapping contact with a second portion of the elongated element in the closed helix configuration, and (b) at least one locking element deployable so as to interconnect the first and second portions of the elongated element so as to tighten together the overlapping portions of the elongated element, thereby stabilizing the closed helix configuration.
