Abstract: A catheter set including an epidural cannula having a dull leading end; i.e., a leading end without a cutting grinding. A first trocar, only the tip of which projects beyond the epidural cannula, may be inserted into the epidural cannula for puncturing. The leading end of the epidural cannula may abut against the dura without the dura being perforated by the tip of the trocar. Thereafter, the first trocar may be removed and the dura may be punctured by a second trocar which is longer than the first trocar and which may be inserted into the cannula. After removal of the second trocar, a catheter may be inserted through the punctured dura into the spinal area, using the epidural cannula as a guide cannula. The puncture caused by the second trocar is entirely closed by the catheter. This opening remains small, since the epidural cannual has no grinding to cut the dura.

Abstract: A spinal cannula adapted for insertion into an epidural cannula that may be advanced up to the dura. In placing the end of the spinal cannula intrathecally, the dura is pierced by the spinal cannula. Then, a guide wire is advanced to that intrathecal position through the spinal cannula. After removal of the spinal cannula, a spinal catheter is advanced over the guide wire and within the epidural cannula. The epidural cannula imparts the necessary directional stability to the catheter upon its advancement and facilitates the passage through the dura already perforated by the spinal cannula.