A stylet instrument is positionable within a catheter to facilitate placement of the catheter during a surgical procedure. The stylet instrument has application in a hemodialysis procedure where the catheter is positioned via a subcutaneous tunneling technique. The stylet instrument includes a hub, first and second stylet members extending from the hub and operatively connected to permit positioning within corresponding lumens of a catheter, and securing means associated with the hub to releasably secure the catheter to the hub. The securing means includes at least one locking detent.