- Reversibility, it's an interesting concept.
Wouldn't it be great if in life,
we knew we could go back and reverse something
if we didn't like it?
Or we changed our minds?
It's reassuring to know
that sometimes you can reverse something.
For example, if you buy something online,
it's good to know you can return it.
Wouldn't it be good if you could date someone
and then go back and reverse it all if it didn't work out?
It would save a lot of heartache.
So today I'm gonna talk about
the reversibility of dermal fillers.
Sometime you might get a problem with a dermal filler,
say a lump or asymmetry,
or even just aesthetic problem that you don't like,
and you wanna reverse this filler.
So how do you do this?
We can do this by a reversal agent,
which is an enzyme that dissolves filler,
and it's called hyaluronidase.
Hyaluronidase, it's a bit of a mouthful.
The most commonly used dermal fillers nowadays
are the hyaluronic acid fillers.
Hyaluronic acid can be broken down by hyaluronidase.
So hyaluronidase is actually the reversal agent
for hyaluronic acid.
It catalyzes the breakdown of hyaluronic acid.
So firstly, hyaluronic acid is a natural constituent
of our skin, our connective tissue, our nerve tissue.
It's found in our joints, in our eyes,
and it's a long sort of sugar chain,
or polysaccharide chain,
and it's very hydrophilic, which means it loves water.
It gives our skin its softness
and gives our joints its fluidity.
In the body we have a very rapid turnover
of hyaluronic acid,
so we have the constant production of hyaluronic acid,
as well as the constant breakdown or turnover
through the body's own hyaluronidases.
The turnover for hyaluronic acid in the body is,
for example, in the skin, it's really only a day or so,
so you know, we're getting,
always getting new hyaluronic acid.
And the difference between hyaluronic acid in the body
and that which is found in dermal fillers
is that dermal fillers have cross-linking
between the long sugar chains of hyaluronic acid.
This makes it more resilient to breakdown
by your own hyaluronidases, which are inside your body.
So, you know, dermal fillers last a very long time.
Cross-linking gives hyaluronic acid dermal fillers
a fairly long duration of effect.
It also gives it a gel-like consistency,
so it's able to, you know, lift an area that you put it in,
for example, if you put it in a cheek,
it can lift your cheek or extend the chin out
if you put it in the chin, for example.
Interestingly, also sperm has a lot of hyaluronidase in it,
because what it does with hyaluronidase is that,
when it needs to get to the egg,
it actually uses hyaluronidase to break down
the corona radiata, which is a surrounding layer of the egg,
before it can get to the egg.
So it uses that to break down this layer
to get to the egg to fertilize it.
So testicular tissue has a high amount of hyaluronidase.
Naturally, this is where most of the commercially available
hyaluronidases are derived from.
They're derived from the testicular tissue of sheep or cows,
so probably that's too much information for you all.
There is human-derived hyaluronidase,
however, it's actually not available in Australia yet.
So, in Australia, the most common commercial hyaluronidases
are Hyalase, and also compounded,
or you know, from a special compounding pharmacy,
compounded hyaluronidases.
Outside of cosmetic medicine,
hyaluronidases are used as a spreading agent,
because what they do is they break down the hyaluronic acid
within the skin or where it's injected,
and it helps things like local anesthetic diffuse
to a greater distance, or diffuse more effectively,
so it's commonly used when people have cataract surgery,
'cause what they need to do there is provide an injection
just under the eye to numb the eyeball
before they replace the lens.
Often local anesthetic is mixed with hyaluronidase,
and this hyaluronidase actually helps the local anesthetic
to spread by breaking down the hyaluronic acid in the body.
As I mentioned previously, the hyaluronic acid in the body
has a very rapid turnover time, so it's fine.
The body regenerates its own hyaluronic acid,
so there's no deficit from that perspective.
So in the cosmetic world,
hyaluronidases are used to break down hyaluronic acid
that is in dermal filler.
And remember, these are cross-linked hyaluronic acids,
the ones that are in dermal fillers,
and they persist for a long time if they're left alone
to wear out by themselves.
The situations you may use hyaluronidase in include
sort of misplaced dermal filler.
For example, you know, maybe a filler was placed
too low in the cheek or too high
and needs to be dissolved and re-injected.
The other problems that we might see which are common are,
say, over-injection, especially around thin areas of skin
where hyaluronic acid fillers can show,
and often we see too much filler under the eye,
which needs to be taken back a little bit,
so you can use hyaluronidase to take the filler back a bit
and possibly re-inject the area again.
You know, you might use it if there's asymmetry
in dermal filler application.
To correct, say, a lump in the lip, for example,
if a dermal filler causes a little bit of lumping
in the lips, you can use it for that.
Hyaluronidase can also be used in a particular situation
where you have superficial filler just under the skin,
and this causes a blue-gray discoloration of the skin,
known as Tyndall's effect.
Tyndall's effect basically reflects light
through scattering, especially the blue wavelengths of light
back to your eyes, so what you see is blue,
and also, it's a similar reason why the sky is blue,
because the sky actually scatters the blue light
back to your eye.
So people don't like blue-colored fillers,
so, especially occurs around the eye.
Hyaluronidase can be used
to dissolve this superficial filler
and remove this blue Tyndall's effect.
An important and serious use of hyaluronidase
is when you have infected filler or granuloma.
So filler will basically act as a nidus
for any infection.
In other words, if you don't get rid of the filler,
you will not get rid of the infection.
Granuloma is basically a hard nodule caused
by the body's reaction to the filler.
It can often be related with infection as well,
so in both cases, the filler needs to be dissolved
and hyaluronidase is the ideal way to do this.
Now, it is important of note,
that you should be on antibiotics
prior to dissolving the filler,
because you can imagine, if you dissolve the filler
whilst it's infected,
you're gonna be spreading that infection around
as the hyaluronidase breaks down the filler
and the hyaluronic acid.
So it's important to be on antibiotics
before dissolving infected filler.
The really important use of hyaluronidase
is actually for emergency situations.
Now, this is a very rare occurrence
that occurs with dermal fillers,
and this is when a dermal filler can actually cause
blockage of an artery.
So we can't see the arteries
when we're injecting dermal fillers,
we don't inject them under ultrasound guidance
or radiographic guidance.
We do it in a sense, blind, or you know,
to all the arteries and veins in many ways.
Knowing anatomy helps to not inject into arteries,
however, if in the rare occurrence that this does happen,
it's really important to have hyaluronidase at hand.
Now, you can tell when an artery has been occluded,
or partially occluded,
because you can see there's differences in the skin.
It may become very blanched or white,
it may become mottled,
so indicating a lack of blood supply.
So as soon as the physician recognizes these signs,
and they have hyaluronidase at hand,
it is possible to inject the hyaluronidase
into the area of ischemia, or lack of blood supply,
and this will help unblock the artery.
A very important use of hyaluronidase.
So we always have hyaluronidase at hand
when we're injecting dermal fillers,
and you know,
we have it always ready to use just in case.
An extremely rare situation
where hyaluronidase would need to be used,
would be for when a dermal filler is injected into an artery
and this artery feeds the eye.
So we're actually blocking off the blood supply
to the eyeball and retina.
This is a very, very rare, extreme example.
There're probably only 50 or so cases worldwide
where this has happened,
but there is potential to actually reverse the filler
that has been placed inadvertently into the artery
that supplies the eye.
If the patient, whilst having filler
complains of loss of vision in one eye,
then it is possible to put in hyaluronidase,
in behind the eye to actually dissolve the filler there.
Scary stuff, this is really,
and thank God I've never had to do this ever.
In fact, it's something that would be extremely difficult
to do, it's not an easy technique.
Anesthetists know how to do this really well,
this technique really well,
because they actually have to inject local anesthetic
behind the eye, like I mentioned before,
for the eye blocks when they do cataract surgery,
it's the same sort of technique.
Certainly not something
that you can easily get practice with.
It is good also to have someone expert on hand,
like an ophthalmologist or anesthetist
who knows how to administer the hyaluronidase
in that exact location, so very difficult.
Just as a side note,
so it is important to inject the hyaluronidase into the area
of ischemia and not necessarily the area
where you've injected the filler.
So, for example, if you inject the filler, you know,
in the nose or one side of the nose,
and the patient has blindness in one eye,
then you need to inject behind the eyeball,
not in the nose.
So that's an important point there,
probably more so for practitioners who do this procedure.
So hyaluronidase, a very important emergency drug
in cosmetic medicine,
as it was a really good tool to adjust a placement
of dermal filler so that it can be re-injected
in the proper place.
Of note, the amount of hyaluronidase to be injected
to correct a certain lump or bump is extremely hard to judge
and you know, I've done hundreds and thousands
of hyaluronidase injections before.
Still, to this day, I find it very hard to judge precisely
how much hyaluronidase to put in
to dissolve a certain amount of filler.
Unless you know the exact amount of filler in there,
and how the hyaluronidase will interact
with this specific amount,
it's impossible to know exactly how much to put in.
So most of the time, it's an educated or calculated guess.
To combat this, I can always get my patients to come back,
because there's always the risk of under or over-dissolving,
and you know, usually people will tolerate under-dissolving
fairly well if it's a cosmetic issue,
but if you over-dissolve them, you know,
people are simply not used to the fact
that they are not filled to the extent they were previously.
I've had a lot of patients who have dissolved,
say, filler around the eye and they ring up the next day
in a panic saying, you know, it's too hollow,
the skin looks different, looks wrinkly or crepey.
They feel it's different.
If I'm gonna dissolve filler,
I usually get my patients back in very quickly,
often the next day.
All right, this is gonna be an interesting
little demonstration in real time
to show you the effect of hyaluronidase
on hyaluronic acid fillers.
So, firstly, I'm gonna put a blob of filler,
just here,
and another blob of filler just here.
Okay, so,
now I'm going to
put some hyaluronidase
on top of one filler, and let's see what the reaction is.
It's really dissolving very, very quickly in real time.
Just to make this experiment a little bit more, um,
so we can see the difference,
let's put some saline here on this one.
And, there's a huge difference.
The hyaluronidase has almost completely flattened
that blob of filler.
Let's talk about the potential side effects
of hyaluronidases.
As with most things, there're always side effects.
One of the main concerns I have when injecting hyaluronidase
is the potential for allergy.
And this can be a very serious allergy.
It's not that common, it's rare,
it might be something like one in a thousand,
but nonetheless, it's a risk that is present
and something that has to be in the forefront
of your mind when you're injecting it.
Often it is said that patients who have an allergy
to bee sting have an allergy also to hyaluronidases,
but I haven't seen a correlation
between this so much myself.
It would also imply that there is something in a bee sting,
which is also present in hyaluronidase.
If you're in a situation
where you need to give hyaluronidase,
and there may be some doubt
as to whether the patient is allergic or not to it,
it's possible to do a test in your forearm, for example.
The practitioner might do a little test of hyaluronidase
in the forearm, wait some minutes,
see if there's any reaction before injecting into the face.
The dose that you put in also might affect
whether you get a reaction to it, so the greater the dose,
the more potential there is for a reaction.
So these can be, you know, life-threatening reactions,
where your tongue swells, your face swells,
and you need to go to hospital to actually get adrenaline,
or you know, to have your airway looked at.
So adrenaline actually has vasoconstrictive effect,
it helps constrict the blood vessels,
and helps reduce swelling around the tongue and the mouth,
and helps regain the airway.
Again, very scary stuff.
This is turning out to be a very scary video.
We always have adrenaline on hand at our clinics
in case this happens.
Now in the 12 years I've been injecting hyaluronidases,
I've seen one reaction, and happened to be in a doctor.
She didn't get much in the way of airway problems,
but she felt a bit sort of unwell,
her pulse rate started going up
and her blood pressure started dropping a little bit,
so I gave her some adrenaline, and that worked well
and brought things back to normal.
And I've also had one severe reaction at our practice,
where the patient had a significant dose of hyaluronidase
to dissolve filler.
Their whole face blew up
and they started to have tongue swelling.
Thankfully, they were sent to hospital
and they received treatment there and everything was okay.
But this is sort of once case in thousands
that have been treated at our clinic.
So, it's a very unusual reaction,
so we always have adrenaline on hand at our clinics.
Ironically, you have to have hyaluronidase on hand
when you do dermal fillers
to prepare for that emergency situation
where you get inter-arterial injection of dermal fillers,
and you also have to have some adrenaline ready,
just in case you get a reaction to the hyaluronidase.
So I think it's essential
that when you're doing dermal fillers,
you have both hyaluronidase and adrenaline on standby.
I hope that's been an informative video for you all.
It hopefully has given you some reassurance
to the fact that you can reverse dermal fillers,
which may give you more confidence to try them out yourself,
if you haven't done so already,
or more confidence to continue using them.
But on the other hand,
you've gotta think of you know, the side effects,
and the potential risks as well.
And I did outline some scary stuff to you,
but again, I want to reiterate,
this is something that is rare,
but you have to be prepared for.
Okay, well thank you again for watching.