Catheter Over Needle (CON) vs Catheter Through Needle (CTN).

This is a catheter used for peripherical nerve block that is inserted at the same time that the needle is being introduced. When the target is achieved, the needle is retired.

This is the traditional catheter used in this centre for peripheric nerve block. In this catheter the needle is introduced first. When the target is achieved the catheter is then introduced throw the needle and after that the needle is retired.