A catheter system includes a positioning catheter for receiving an injection needle into its lumen. The injection needle incorporates a web member mounted directly onto its shaft. As the injection needle is moved in a distal direction to exit from the lumen of the catheter, the web member is biased to transition from a folded configuration, and into a flared configuration. Specifically, this transition occurs when the injection needle is deployed more than a predetermined distance "d" beyond the distal end of the catheter. In its flared configuration, the web member is disk-shaped and is oriented perpendicular to the needle. Thus, it acts as a barrier to limit the depth of insertion of the needle into target tissue of a patient, to a depth less than "d", and to prevent perforation of the target tissue by the catheter tip.
