Devices, systems, and methods for immobilizing an implanted catheter tip while the catheter is anchored relative to surrounding tissue. In one embodiment, a cannula system is included that incorporates a cinch tube for guiding the catheter to a target site within a body. The cinch tube may define a cinch window to receive therein a cinch member operable to immobilize and occlude the catheter. The cinch tube may also include an elongate opening proximate the cinch window. The elongate opening allows extraction of a portion of the catheter and subsequent severing of the catheter above the cinch window/occlusion site.