Toggle

Anterior approach (according to Meier)

Print

The anterior approach to the sciatic nerve is advantageous in patients who cannot be reasonably placed in the lateral recumbent position due to pain or their condition.

 

Anatomical landmarks

Posterior superior iliac spine, symphysis, greater trochanter

anterior1

 

Block technique

The patient is supine on his back, with the leg in a neutral position, not rotated outwardly like in the femoral nerve block. The line connecting the anterior superior iliac spine and the symphysis is marked. A parallel to this line is drawn to the greater trochanter. The length of the first line (between the anterior superior iliac spine and the symphysis) is divided into thirds. A perpendicular line is drawn from the medial third point to the distal. This perpendicular line intersects the second guideline. This puncture is made at the point of intersection. Use finger of one hand to feel along the muscle compartment between the rectus femoris muscle and the vastus medialis and/or the sartorius muscle, taking the femur as a counter point. By doing so, the neurovascular bundle is forced to the medial. The puncture is made lateral to this, thereby minimising the risk of hitting a vessel. Insert the stimulation needle (Stimuplex® D 120 mm) into the skin at a 75-85° angle, guiding it in a dorsocranial direction. Stimulation of parts of the femoral nerve is possible in the superficial areas. At a depth of 6-10 cm, you reach the dorsal thigh compartment. The sciatic nerve is encountered by advancing the needle a bit further. The tip of the needle is positioned correctly when plantar flexion (tibial part) and dorsal flexion (peroneal part) are elicited.