Nerve Bundles

A popliteal sciatic nerve block done with the Sonosite SII ultrasound machine is a clinically valuable technique that results in anesthesia of the calf, tibia, fibula, ankle, and foot. Anesthesiologist Dr. David Auyong MD of Seattle, Washington here reviews scanning techniques and sonographic landmarks for the procedure, discussing important structures, techniques to visualize the popliteal vein, types of probe used, and needle/injection choices. The Sonosite II allows precise placement of local anesthetic, much reducing patient discomfort, providing superior visualization of the nerve and the needle during block placement.

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- The Popliteal Sciatic Nerve Block
is a good block to do for the sciatic nerve
because this is where the sciatic nerve
is found most shallow.
This block can be performed for post year knee pain
after knee surgery, as well as, calf, foot
and ankle surgery.
This is the main nerve that supplies the lower leg.
I find a lateral position gives you good control
of the patients airways if you sedate them
as well as good ergo-dynamics to do the block.
Here we have our patient positioned laterally
with a pillow between the legs for comfort.
To do the Popliteal Sciatic Nerve Block
we use a linear probe.
The linear probe allows us to see structures well
in the shallow plane,
but gives us a wide field of view
to see our needle approaching the nerve.
To perform the Politeal Sciatic Nerve Block
we put the probe directly in the back of the knee.
Placement of the probe in the back of the knee
reveals a structure of the nerve, the vein, the artery.
I call this structure, the snowman in the back of the knee.
You have three circles on top of each other.
The upper most circle represented by the tibial
component of the sciatic nerve.
The middle structure represented by the vein
and the deep structure represented by the popliteal artery.
If we put color Doppler on the screen
we are able to see the pulsating artery
in this area.
Sometimes it's difficult to see the popliteal vein
because this is a low-flow state,
such as we see here.
To visualize the popliteal vein better
we can squeeze the back of the calf,
increasing venous flow through the popliteal vein,
such as this.
There we can see increased venous flow
through the popliteal vein represented better
by color Doppler.
Now, as I mentioned, this is only the tibial component
of the sciatic nerve.
We wanna get the nerve where it comes together
and has both components, the peroneal
and the tibial component.
As we scan up the leg, here we now see
the peroneal component laterally,
the tibial component medially,
the popliteal vein and popliteal artery.
On the medial side we see the semitendinosus
and semimembranosus muscles.
On the lateral side we see
the biceps femoris, long and short heads.
As we keep going up the leg
the tibial and peroneal components join into one nerve.
Sometimes we block the nerve at this level
where the two components are joining.
This allows us to get both components
with a single injection at the nerve.
My needle approach for these blocks
are gonna be from lateral to medial.
What I typically do is measure the depth
of the sciatic nerve in this setting.
Here the sciatic nerve is approximately
one-and-a-half to two centimeters deep to the probe.
So if I measure one-and-a-half to two centimeters deep,
my needle is gonna come in completely perpendicular
and have a very bright view of the needle
and needle shaft as it advances to the nerve.
Now, I typically like to inject deep to the nerve
as well as superficial to the nerve
in order to get complete surrounding
of the popliteal sciatic nerve
for the most rapid onset for this block.
Typical volumes used are 20 to 30 milliliters
of local anesthetic.
This block takes some time to onset
and studies have shown even with complete surrounding
of the nerve, it takes up to 30 minutes
for the nerve block to onset in most patients.
Here we see the popliteal sciatic nerve
surrounded by the biceps femoris laterally
and the semitendinosis/semimembranosis medially.
Our needle is advanced directly above the nerve
and the local anesthetic is injected,
pushing the nerve deeper.
We then withdraw the needle
and readvance the needle again close to the nerve
so we can get local anesthetic spreading
to the medial side of the nerve,
which is more of the tibial component.
Now you can visualize both the peroneal and tibial component
with a local anesthetic completely surrounding the nerves.

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5508136021001

https://youtube.com/watch?v=X0wqmWXEcTg

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S Series: Sciatic Nerve Gluteal Level

S Series: Sciatic Nerve Gluteal Level

M-Turbo: Popliteal Nerve Block with Needle

M-Turbo: Popliteal Nerve Block with Needle

M-Turbo: Femoral Nerve and Artery

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S Series: Brachial Plexus Supraclavicular Level 1

S Series: Brachial Plexus Supraclavicular Level 1

M-Turbo: Brachial Plexus Supraclavicular Injection

M-Turbo: Brachial Plexus Supraclavicular Injection

M-Turbo: Brachial Plexus Interscalene Level 5

M-Turbo: Brachial Plexus Interscalene Level 5

M-Turbo: Brachial Plexus Interscalene Level 4

M-Turbo: Brachial Plexus Interscalene Level 4

M-Turbo: Brachial Plexus Interscalene Level - 3

M-Turbo: Brachial Plexus Interscalene Level - 3

M-Turbo: Axillary Nerve Post Injection

M-Turbo: Axillary Nerve Post Injection

How To Perform A Popliteal Nerve Block

How To Perform A Popliteal Nerve Block

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