Name:
ACA- Hadzic- Peripheral Nerve Block 3e- Ultrasound-Guided Popliteal Sciatic Block
Description:
ACA- Hadzic- Peripheral Nerve Block 3e- Ultrasound-Guided Popliteal Sciatic Block
Thumbnail URL:
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Duration:
T00H08M57S
Embed URL:
https://stream.cadmore.media/player/ef7713d4-5498-49b1-a768-ae972051f93a
Content URL:
https://asa1cadmoremedia.blob.core.windows.net/asset-862748b0-2371-499d-94b3-56c94269c1db/ACA- Hadzic- Peripheral Nerve Block 3e- Ultrasound-Guided Po.mov
Upload Date:
2022-02-23T00:00:00.0000000
Transcript:
Language: EN.
Segment:0 .
DIGITAL INTRO TUNE:
DR. HADZIC: We're going to do now a popliteal sciatic block or the sciatic block in the popliteal fossa. As you could see the patient positioning for this particular block is actually in the oblique position or lateral position. In this particular position, the patient can simply be put back after the block performance without needing to reposition all the EKG leads, pulse oximeter and things like that.
DR. HADZIC: So, as you could see, this is a lateral or oblique position with the leg very slightly bent and extremely important is when you use nerve stimulation for monitoring the motor response or needle-nerve contact, it is important to notice that the foot has to be lifted off the bed because oftentimes the only twitch you may perceive, could be a twitch of the tibial nerve or common peroneal, could be a twitch of the tibial nerve or common peroneal, and those could be just very slight or faint twitches of the toes and you have to be able to perceive them if they occur.
DR. HADZIC: So the foot has to be elevated. Yep, okay, so now what we're going to do is we're going to apply a sterile drape. This is the popliteal fossa crease, this is the tendon of the biceps femoris muscle, tendon of the semitendinosus and semimembranosus muscle. The initial probe or transducer placement will always occur 2-3 centimeters above the popliteal fossa crease and very close to the biceps femoris tendon.
DR. HADZIC: So, that will be our intended goal. Here we go, so starting the scan at the popliteal fossa, just slightly above the popliteal fossa crease, very quickly reveals the tibial nerve and the common peroneal nerve. Underneath the tibial nerve you could see there's a very faint image of the popliteal vein. This is very important to notice because oftentimes when the needle is placed inside the popliteal nerve or sciatic nerve sheath, there could be a tendency for the needle to pop through that sheath and lodge into the tibial vein or popliteal vein that is, which needs to be avoided.
DR. HADZIC: And now as we scan slightly proximally here, we get to the image in which the tibial nerve and the common peroneal nerve are clearly seen enveloped by a common tissue sheath which is called the sciatic nerve sheath, and the sciatic nerve sheath is much debated in the literature as to what it is, whether it exists or it doesn't, but clearly there is a connected tissue envelope that connects the two nerves together into a common space that allows a single injection of the local anesthetic for the block of the sciatic nerve.
DR. HADZIC: Let's look at how that looks like on Nysora's Reverse Ultrasound Anatomy. Here we have the tibial nerve and the common peroneal nerve. We see the surrounding muscles and how the sheath has been formed by the myosin of those muscles. And what we want to do with our scanning process is to arrive to the position in which the two nerves are sufficiently separate to allow needle insertion into the sheath, but also close enough together to be inside the sheath, so to allow one single injection of local anesthetic to be successful.
DR. HADZIC: A little bit deeper inside the fossa, we also see the tibial artery, which has no significance because there is no neurovascular sheath. The sciatic nerve is completely independent of the vasculature, but again, here you can see the pressure and release of the pressure of the ultrasound transducer opens and closes the popliteal vein which needs to be avoided.
DR. HADZIC: So, the stock maneuver with this particular block to accomplish the best images is again placement of the transducer about few centimeters above the popliteal fossa crease, pressure, and as you can see, pressure immediately identifies the tibial and common peroneal nerve, and a slight angulation of the transducer usually distally, which really compresses the fascia sheaths usually distally, which really compresses the fascia sheaths and picks up the sciatic nerve sheath in this particular location.
DR. HADZIC: In this image also what we see more superficially is actually the sural nerve, which is at this point in time actually outside of the sciatic nerve sheath. Okay. So, let's find now an image, okay, that actually allows us the needle placement. So you want to place this in the middle, in the middle. Okay. Good. Go slightly below, okay, because you'll want to start seeing these two nerves separate actually, and apply a little bit of pressure and just a little bit of tilt downward, like this.
DR. HADZIC: This will pick up the sheaths, oh you see that? That's now an entirely different image that allows you to see clearly the fascial sheaths right there, and this is where the needle needs to go. Okay. So, let's do that. Keep the image of the nerve in the middle, so that really facilitates the needle placement. Okay.
DR. HADZIC: Okay. So, now we can see the needle is exerting a pressure on the sciatic nerve sheath. Okay, and there's a clearly perceptible pop as you enter the sheath because that sheath is rather thick. Push, push, one more time, push. Okay. When the needle enters the sheath, oftentimes there's a snap back as the needle pierces through the sheath, the sheath eventually pops back into its original position due to its elasticity.
DR. HADZIC: Okay, so this is the time when we do the RAP maneuver, which is aspiration, response is negative, as we don't see any response to the nerve stimulation of the foot, aspiration is negative, and the opening injection pressure is low. Okay. And now with this injection we can see that the local anesthetic spreads inside the sheath, pushes the two nerves away from each other.
DR. HADZIC: We probably could adjust this a little bit by pulling the needle back a tiny bit. That is what you want to see. See this? So, this makes sense, otherwise from here, you don't see anything from above, it's limited. Okay. Good. I like that. Now, if you scan a slightly higher bit over here, there you go, stay there.
DR. HADZIC: Okay, you can see how the local anesthetic is now filling up that sheath and pushes the two nerves away. So, if you continue going up now, more proximally to scan, this is now a position in which the sciatic nerve sheath is now strengthened by the myosin of the surrounding muscles, if your needle position is correct and inside the sheath, here, you definitely are going to see spread of the local anesthetic inside the sheath even more proximal to the site of injection, and there is the image you want to see.
DR. HADZIC: When you see this, you cannot be anywhere else, but inside the sciatic nerve sheath. And that really is what it takes to accomplish a successful popliteal sciatic block. Okay. You can take the needle out. And now we're going to do a joint scanning to demonstrate what happens with the local anesthetic. So in here, you can clearly see the local anesthetic inside the sheath, that's the sheath of the sciatic nerve, that's the local anesthetic, that's the common peroneal nerve and the tibial nerve, and both nerves are clearly enveloped by local anesthetic.
DR. HADZIC: Even if you go proximally where the nerve diverges, you could see the local anesthetic follows the common peroneal nerve in its sheath, and the same happens for the tibial nerve as we go more distal, there's local anesthetic inside the sheath of the tibial nerve.
DIGITAL INTRO TUNE:
