Control

The authors systematically use opacification catheter before injection of local anesthetic solution in order to check the proper position of the catheter as well as the space of diffusion (Figures 4 and 5 demonstrate the psoatic opacification of space). The form in spindle corres-ponds to the drawing of the muscle psoas with the pool showing the space between the muscle psoas and the quadratus lumbarum. It is important to rule out the epidural spread, as well intra-peritoneal, epidural or too cephalad placement of the catheter. For this purpose we use 25 to 30 ml of radio opaque -- not neuro toxic solution.