Devices, systems, and methods for immobilizing an implanted catheter tip while a catheter stylet is withdrawn from the catheter. In one embodiment, a cannula system is included that incorporates a catheter retainer securable to an immobilized guide cannula. The retainer may include one or more surfaces that operatively engage the catheter and effectively restrain the catheter relative to a head of the guide cannula. Other embodiments may also include a stylet holder operable to engage the stylet with a consistent and repeatable clamping force that is independent of clinician-applied force.
