The position of epidural catheters in obstetric regional anaesthesia.

The fate of plastic catheters threaded into the epidural space was studied radiographically in a total of 125 catheters in 75 patients. The longer the segment of catheter, the less likely it is to reach the intended position, because it may curl up or become deflected. The most reliable technique for accurately placing an epidural catheter at any specific level is to enter the epidural space as close as possible to that level, so that the catheter does not need to be threaded for more than 2--3 cm.