Anterior

- The Sciatic Nerve Block can be used for surgery of the
leg, knee, foot and ankle.
To do the Sciatic Nerve Block,
you can block it at the Popliteal region
or you can block it higher.
Some benefits of blocking it higher
are to be above the tourniquet,
so you don't have to worry so much about nerve ischemia.
You may also get the Posterior Femoral Cutaneous nerve
of the thigh, which comes off very high on the Sciatic nerve
and it's also medial to the Sciatic nerve, as well high up.
This way, you can cover any kind of pain of incision
in the upper thigh area.
To position patients for Subgluteal Sciatic Nerve Block,
we position the patient lateral.
This way, the patient is comfortable,
they can be well-sedated and you can place a probe
on the posterior side of the leg and advance the needle
from lateral to medial.
The probe we use for a Sciatic Nerve Block
is a curvilinear low-frequency probe.
The reason we use this probe is because
it penetrates deeper and this is useful in larger patients.
So some of the landmarks we use
for the Subgluteal Sciatic Nerve Block
are the Greater Trochanter laterally,
the Ischial Tuberosity medially, and
directly in between these two is where we place the probe
The initial view we see is the Greater Trochanter
on the left side of the screen.
On the right side of the screen,
we see the Ischial Tuberosity.
There is a large muscle, the Gluteus Maximus
at the superficial level of the screen.
Underneath the Gluteus Maximus is a hyperechoic nerve,
the Sciatic Nerve.
Between the two bony landmarks is the Quadratus Femoris.
So on this level, the nerve is sandwiched between
the Gluteus Maximus and the Quadratus Femoris.
The nerve here can appear wide, flat or triangular.
It is not a circular structure like some people imagine.
Needle approaches for the Sciatic Nerve Block,
whether is be here, at the Mid-Femoral region,
or higher up at the Subgluteal region,
are performed from a lateral-to-medial approach.
The lateral-to-medial approach usually starts
three to four centimeters away from the probe in this angle.
Now, higher up we'll use the same needle approach.
We can see the triangular Sciatic Nerve here,
and we'll start the needle angle about here.
Now you typically put my nerve
on the distal side of the screen from where my needle
is entering, in order to see the needle better
and travelling across the screen to the nerve.
Typical volumes are 20 to 30 milliliters
of local anesthetic.
Because this nerve is so deep in some people,
some anesthesiologists like to approach this nerve
from an Out-of-Plane needle angle.
And Out-of-Plane needle angle would be in this direction
into the Sciatic Nerve.
Other people like to turn this probe in a longitudinal
direction and see the nerve in long axis.
So here we are turning the probe in the long axis
and following that nerve in the longitudinal pattern here.
So now we see the Sciatic Nerve going down the leg.
The needle approach in this orientation would be in
this angle in plane of the ultrasound beam
down to the Sciatic nerve.
- (Dr. Auyong) Here you can see the Greater Trochanter
on the left side of the screen, the Ischial Tuberosity
on the right side of the screen, the Gluteus Maximus
superficial and a 21 gauge needle
advancing to the Sciatic Nerve.
The Sciatic Nerve is below the Gluteus Maximus
and above the Quadratus Femoris.
Our needle is advancing above the Sciatic Nerve
to attempt to get local anesthetic to spread
to the medial side of the nerve.
Which would be more likely to get the larger
Tibial component, as well as the posterior femoral
cutaneous nerve of the thigh.
Now you can see the nerve, which very hyperechoic,
below the local anesthetic.

Brightcove ID

5508120191001

https://youtube.com/watch?v=IL4qqETpb0k

Body

Dr. David Auyong reviews scanning techniques and sonographic landmarks for an ultrasound guided nerve block .

3D How To: Gluteal Sciatic Nerve Block

Read more about 3D How To: Gluteal Sciatic Nerve Block

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3D animation demonstrating an ultrasound guided Gluteal Sciatic nerve block.

Clinical Specialties

Anesthesiology (Regional)

Media Library Type

How To Videos

Subtitles

- [Voiceover] A curved array transducer
with a nerve exam type is used to perform
a ultrasound guided sciatic nerve block.
The target depth is approximately four to six centimeters
in an 80 kilogram adult.
The patient is positioned in a lateral decubitus position
with the hip and knee flexed.
The transducer is placed between the greater trochanter
and the ischial tuberosity in a transverse position
just proximal to the gluteal fold
with the orientation marker directed laterally.
The bony landmarks will appear
as bright hyperechoic crescents with posterior shadowing.
There are several layers of tissue
between the bony landmarks, which should be identified
from superficial to deep, including adipose tissue,
the gluteus maximus muscle and quadratus femoris muscle.
The sciatic nerve lies deep to the gluteus maximus
and superficial to the quadratus femoris muscle.
It appears as a bright hyperechoic oval
or triangular shaped density.
The transducer should be moved slightly cranially
or caudally from the initial position
by slightly rocking the transducer
so the beam is perpendicular to the nerve
for the best echo reflection if it is difficult to identify.
When the transducer is moved distally in the thigh,
the sciatic nerve becomes more oval in shape
and is found more superficially between the biceps femoris
and abductor magnus muscles.
The needle is advanced using an in plane technique.
The needle is positioned one to two centimeters lateral
to the transducer and advanced slowly under the transducer.
The initial end point for the needle
is just lateral and deep to the nerve.
The local anesthetic is injected incrementally
close to the nerve.
For a successful block, a spread of locals
should be observed around the medial side
or tibial component of the nerve.

Brightcove ID

5508134308001

https://youtube.com/watch?v=xvAY_bu_S7A

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S Series: Sciatic Nerve Gluteal Level

S Series: Sciatic Nerve Gluteal Level

How to: Subgluteal Sciatic Nerve Block

How to: Subgluteal Sciatic Nerve Block

3D How To: Gluteal Sciatic Nerve Block

3D How To: Gluteal Sciatic Nerve Block

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