Ultrasound-guided popliteal sciatic nerve block positioning

Dapperduane

Moderator
Staff member
Aug 8, 2019
45
1
8
Gilbert, AZ
Mindray was demonstrating their new ultrasound equipment and I was able to use it for a popliteal block. I didn't think the image was anything amazing but I was impressed with all of the features on the machine. It continuously records video so that I could pull images and video clips from "before" I wanted the nurse to hit the record button, pretty neat! Here are a few images and short videos. I like to have the patient supine with the leg bent at the knee by placing a stack of blankets under the lower leg. I then place the probe posteriorly and trace the sciatic nerve, locating cephalad to the bifurcation. I place the blunt needle (typically 22# 80mm is my choice) anterior to the biceps femoris tendon in the groove since the bent knee accentuates this. I approach the nerve tangentially (so that the needle would glance off the nerve if too close) typically aiming under the nerve bundle. If I am able to get the local anesthetic under all the fascial layers to completely bathe the sciatic nerve then it is one shot, if only half of it is bathed (lifting the nerve up in the U/S image)then I will put a final amount in the 2 'oclock position, always aiming tangential. The video shows the filling of LA around the nerve.

202005210934200012NERVE BLOCKS.JPG202005210935060015NERVE BLOCKS.JPG202005210935160016NERVE BLOCKS.JPG202005210935520019NERVE BLOCKS.JPG
View attachment NERVE BLOCKS.mp4
View attachment NERVE BLOCKS2.mp4
 

Dapperduane

Moderator
Staff member
Aug 8, 2019
45
1
8
Gilbert, AZ
Some people like to do these prone. I feel it is safer if the knee is flexed because this gives some slack to the sciatic nerve, allowing it to move if you accidentally "bump" it. So if you do it prone, be sure to put some pillows under the lower leg to create that flex.