hi my name's max feinstein and i'm an anesthesia resident at the mount sinai
hospital in new york city in this video i'm going to be explaining the difference between spinals,
epidurals, and combined spinal-epidurals. and also what this guy is doing back here. if you find this
video interesting or helpful i'd really appreciate it if you liked it and subscribe to the channel
i'd also recommend that if you don't like looking at videos or images of needles,
you check out a different video of mine -- this probably wouldn't be the one for you
the word epidural actually just refers to a space between two layers of tissue in the back,
namely the ligamentum flavum and the dura. and the epidural space contains a number of different
things including lymphatics, some blood vessels, and nerve roots that travel through it. when
doctors refer to placing epidurals what we're really referring to is placing a piece of
plastic tubing inside of that space so that we can deliver medication through the tubing.
i'm sure what immediately caught your eye as you started watching this video
is the fact that this half mannequin is in a really weird hunched-over position
and the reason for that is that positioning is an enormous part of a successful epidural placement.
if you take a look at this model of a spine right here,
where these are the spinous processes, which is what you would feel on somebody's back,
you can see how when the model is up straight like this there's really no way to pass anything
in between the spinous processes but if you have a patient who is hunched over like this you can
see how the space really opens up in a way that would allow you to pass, in this case, a needle
in between the spinous processes before i show you the relatively large 17 gauge Tuohy needle that we
use to place the epidural catheter, let me first show you the small 27 gauge needle that we use
to inject local anesthetic so that patients don't feel the Tuohy needle going in. this
is that small 27 gauge needle we use to inject local anesthetic. after having placed hundreds
of epidurals i can tell you that what's generally the most painful part is just the bit of stinging
that occurs for about 10 seconds or so from the local anesthetic. once the local anesthetic's
in place then we go ahead and start inserting the 17 gauge Tuohy needle which looks like this
you can appreciate how the Tuohy needle has markings every centimeter so that we can keep
a very close eye on how deep this needle has gone. one of the really important features of
this needle is the special tip that it has which is designed to allow the passage of a plastic
catheter that will go up into the epidural space and not continue forward. a common way to identify
the correct anatomical location for placing either a spinal or an epidural is to start by palpating
the patient's iliac crests. the iliac crests are at approximately the level of the L3 to L4
interspace which is a common place to insert a spinal or an epidural. and so once i've
identified that interspace, i put a finger on either side here. i've got my local anesthetic
which i'll start by injecting superficially to make sure that the patient doesn't feel
the Tuohy needle going in. some people also like to use this needle as a "finder needle" to make
sure that you don't run into any type of bone as you inject deeper. it's worth pointing out
that the epidural space is typically at least five centimeters deep from the skin or possibly
more depending on the patient's BMI and a needle like this is only about four centimeters long
so it's generally not going to be deep enough to even get to the epidural space. now that i've
identified where i'd like to place my Tuohy needle and i've anesthetized that area i'll go ahead and
very carefully insert the Tuohy needle. and i can feel as i'm going past each one of the ligaments
and what i'm feeling for is the ligamentum flavum which has a very distinct hard stop but you have
to be extremely careful when doing this to not advance past the ligamentum flavum which can
lead to an inadvertent dural puncture and result in a complication called a post dural puncture
headache. if you watch closely you can see that my needle meets some resistance right here which
corresponds with the ligamentum flavum. at this point i'll very carefully remove the stylet
from the Tuohy needle. now i can attach a syringe that's filled with either air or saline and in
this case i'll use air so that i can very slowly transverse the ligamentum flavum. and once i've
gotten just to the other side of the ligamentum flavum this air filled syringe will collapse
and allow me to know that i'm in the epidural space. so I advance, tap, advance, tap, advance,
tap, advance, tap, and you can see how the air very easily goes in now allowing me to be quite
confident that i have reached the epidural space. at this point i detach my syringe
and now i'll take my epidural catheter and thread it through the Tuohy needle. the epidural catheter
comes with depth markings on it so i can know exactly how far i have to advance it.
now that i've advanced my epidural catheter i can very carefully remove the Tuohy needle while
simultaneously making sure that the epidural catheter stays exactly where i placed it.
at this point the Tuohy needle itself is out and the epidural catheter remains in place.
now i'll apply sterile adhesive dressing over the epidural catheter so it doesn't move
and then i can continue to infuse medication that goes through this catheter into the epidural
space. there are a number of different medications we can administer through the epidural catheter.
very commonly we'll give a combination of a local anesthetic called bupivacaine as well as an opioid
called fentanyl, both of these in extremely low doses. combining medications like this
allows us to deliver a smaller dose of each one of them because they work synergistically to provide
anesthesia. i should point out that when we do include opioids in our epidurals it's typically
in such low doses that it doesn't cause any amount of euphoria or any kind of feeling
that would evoke addictive behavior. typically the amount of time it takes for the medication
going through an epidural to relieve pain is about 20 minutes, give or take, and that can
really last for as long as we need it to as long as we continuously infuse the medication through
the epidural catheter into the epidural space. that's also why epidurals can be really excellent
choices for pain control after major abdominal or thoracic surgery where we can continue delivering
medication through the epidural for as long as the patient is in the hospital and needs pain relief
the term spinal refers to an injection of medication that goes in the subarachnoid
space which is located deeper than the epidural space. the subarachnoid space
contains cerebrospinal fluid, nerve roots and blood vessels that go to those nerve roots.
it's extremely important to point out that the spinal cord ends at approximately vertebral
level L1 or L2 in most people and so when we're placing spinals we're doing
that below the level of the spinal cord so that we don't cause any damage to it
again start by numbing the area with the small 27 gauge needle and a bit of local anesthetic
and then through the anesthetized area we insert a special short needle called
an introducer. and an introducer allows a longer more flexible needle
to pass through and eventually reach the subarachnoid space. the spinal needle
easily passes through the introducer and once we think that we've reached the subarachnoid space
we remove the orange-tipped stylet that's inside the spinal needle. this allows cerebral spinal
fluid to drip back and let us know that we're in the right location and at that point we go ahead
and connect a syringe to the spinal needle and inject our medication into the subarachnoid space
for placing a spinal, I'll again start by identifying the iliac crest, palpate
the L3-L4 spinous processes and identify the interspace
use a local anesthetic to anesthetize the skin
take my introducer needle and bevel up i will insert the needle into the target area. this
needle should advance all the way in, and then into the introducer i'll take the spinal needle
and here i'm again feeling for ligamentum flavum which i just felt myself go through
and so i'll go ahead and remove the stylet. and if this were a person, this is where
i would expect to see cerebral spinal fluid floating back at me at which point i could take
the medication that i intend to eject into the subarachnoid space, connect to the spinal needle,
draw back slightly to make sure that it draws back easily, and then i get more cerebral spinal fluid
and then go ahead and inject the medication which goes into the subarachnoid space.
i'm going to go ahead and remove all of these apparati together
just like with epidurals, the medication that we choose to deliver through a spinal
can vary depending on what exactly the surgical and patient's needs are.
namely, where exactly does the patient need to be anesthetized and for how long? for example in
c-sections it's very common to use a combination of the local anesthetic bupivacaine also mixed in
with dextrose and also mixed in with an opioid for example fentanyl. spinals can last up to several
hours, more or less depending on exactly what the formulation of medication was that was delivered
into the subarachnoid space. while spinals are very commonly used for c-sections they're also
very commonly used to provide pain relief for hip surgery or knee surgery so that we can allow
a patient to not feel anything below the level of, say, their belly button for a several hour
period. and then once the surgery is done they'll start to regain sensation and then we can provide
pain control as needed. also just as a side note, when people refer to spinal tap they're referring
to accessing the same subarachnoid space with a needle but instead of delivering medication into
it, the tap refers to draining some cerebrospinal fluid from it for analysis in a laboratory
now that you know what an epidural is, and you know what a spinal is,
then you can guess that a combined spinal-epidural is.. both of them combined
and it's actually really cool to take a look at the needle that allows us to do
both a spinal and an epidural at effectively the same time. recall that when we're placing
an epidural we use this Tuohy needle to thread the epidural catheter in place. well when we
want to do a combined spinal epidural, then once we've got the Tuohy needle in place, we
can inject medication into the subarachnoid space that is, recall, deeper than the epidural space
by inserting this Gertie Marx needle or something similar through the Tuohy needle. so we take our
Tuohy needle which has gotten into the epidural space and we can insert a Gertie Marx spinal
needle that goes through that and will penetrate even deeper and get into the subarachnoid space.
once we've accessed the subarachnoid space using this 26 gauge Gertie Marx needle we can take out
the stylet which leaves a hollow needle in place. at this point if we were doing this on a patient
you would be able to appreciate cerebral spinal fluid dripping back from the Gertie Marx needle,
and then we can connect a syringe of whatever we're using for our spinal and inject it directly
into the subarachnoid space. once we've completed that injection we keep our Tuohy needle exactly
in place and remove the Gertie Marx needle that was going to the subarachnoid space,
and now we still just have our Tuohy needle which is in the epidural space. we can start inserting
this flexible plastic epidural catheter which goes directly through the needle like this,
and you'll be able to see how instead of going straight forward out the tip of the
needle it comes out at an angle and when it's in the epidural space, it will actually just
point straight up. we typically advance the epidural catheter approximately five
centimeters into the epidural space and you can imagine it would be pointing up just like this
at the other end of this plastic tubing is an injection port that allows us to connect to
any medication that we'd like to continuously deliver through the epidural
just like for both the epidural and the spinal, i'll start by identifying my landmark the iliac
crest going over to approximately the L4 to L5 interspace using my
local anesthetic to anesthetize the area where i'm going to do the combined spinal-epidural. perhaps
i'll use it as a finer needle as well now that the area is anesthetized i again take the Tuohy needle
i am now feeling for the ligamentum flavum that will be met with a change of resistance and often
times a bit of a click that's either felt and/or heard. once I've gotten to the ligamentum flavum
i remove the stylet from the Tuohy needle. again i will take either a saline or an air filled syringe
connect and very gently push through the ligamentum flavum and i'm feeling for a
loss of resistance which you can appreciate right here. i will now disconnect my syringe,
take my Gertie Marx spinal needle, advance it through the Tuohy, and i'm feeling again for
a loss of resistance. once i've lost resistance i can go ahead and remove the stylet from the Gertie
Marx needle and this is where if i were doing this on a person i would see cerebral spinal fluid
floating back at me, at which point i could take the medication that i'm using for a spinal,
connect to the Gertie Marx needle
gently draw back to make sure that it easily takes back some CSF, and then very gently inject
the spinal, and then i'll take out the Gertie Marx needle while leaving the Tuohy in place
which then allows me
to take my epidural catheter and thread it into the Tuohy needle
just as i did before as part of a regular epidural. you might see this in cases where
a patient is having their third or fourth c-section and we anticipate that there's
going to be quite a bit of scar tissue that was created by prior c-sections, so the c-section
itself is going to take a longer period of time so we'll need the immediate effect of the spinal
and then continue to provide pain relief with the epidural, hence combined spinal-epidural
if you found this interesting and would like to see videos about
different types of procedures why don't you check out this video that
i made about inserting a very large IV called a rapid infusion catheter
thanks very much for watching and a big thank you to the mount sinai department of
anesthesiology for letting me use the equipment and space to make this video see you next time