Lower limb blocks can either be done at the level
of the femoral nerve, in the video we just saw
that was a femoral nerve block, and that will give you
an excellent block of the thigh, down
to the knee. And is good for post-operative
pain control, not a great block
for actual surgery. And then we do our
other blocks tend to be lower in the leg,
behind the knee in the popliteal
fossa or down at the ankle. So
usually, if you've got, if you're going to use a lower
limb block for anesthesia, it's better to just go ahead
and do a spinal or an epidural, and use
that block for the anesthesia for the surgery.
And then do a femoral nerve block or a sciatic
nerve block, or a combination of the both for
post-operative analgesia. I'm showing you how we do
a femoral nerve block. Sciatic nerve block is significantly
more difficult and requires a lot more
skill to do than a femoral nerve block.
So here's a demonstration of femoral nerve
block using just landmarks and palpation rather
than the ultrasound guided technique we showed you
a moment ago. And when you palpate
the inguinal area it's very easy to feel the femoral
artery. And if you consider the femoral
canal, to consist of artery - nerve - ring,
you can think in the position of all these
organs, if you think of Mr. VAN.
So in this acronym
the M stands for median, so right medial
inside the leg. R stands for the femoral
ring. V is the femoral vein.
A is the femoral artery. And N
is the femoral nerve. So if you're feeling the artery,
the nerve should be just lateral to the artery.
This is the position that's often used for the sciatic nerve
block. As I mentioned earlier, this is a more difficult
block. The landmarks are often difficult
to identify, particularly in obese patients.
And it's not commonly done, unless you're actually
a very good regional anesthesiologist.
The ankle block is commonly done
for foot surgery, in which
a tourniquet isn't used to prevent bleeding during the surgery.
And it's a relatively easy block, they're usually
3 needle positions in the front of the foot. One
a little bit lateral, one a little bit medial, and you
can see the three nerves that we try to catch
with that. And that will give quite good anesthesia
to the whole foot. If you need to use a tourniquet
however, and many surgeons require this
to prevent bleeding in the foot, the tourniquet
has to be placed higher than this. And tourniquets
produce a lot of pressure and can become very
uncomfortable in a relatively short period of time.
And this block doesn't prevent the sensation of the tourniquet.
So, if you're going to use a tourniquet, you
really can't use this block.