This comprehensive course will give you the fundamental knowledge needed to begin performing cataract surgery by phacoemulsification and extracapsular removal. Each step from preoperative evaluation to postoperative care will be covered to help prepare you for the operating room.
02.05 - Capsulorhexis
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Del curso dictado por University of Michigan
Introduction to Cataract Surgery
64 calificaciones
De la lección
Unit 2: In the Operating Room and Getting to the Cataract
This unit begins in the operating room after the patient is prepped and draped. It covers each step needed for you to access the lens. Once you begin operating, you will realize that each step of surgery has a domino effect. If the beginning steps are not done skillfully, it will make the rest of the case more difficult.
Conoce a los instructores
Elizabeth Du, M.D.Clinical Assistant Professor
Department of Ophthalmology & Visual Sciences, Kellogg Eye Center
Hi, folks.
It's me again.
We're going to talk about Capsulorhexis, you know,
the creation of that fabulous opening in your anterior capsule.
One of the most difficult parts of cataract surgery.
Challenging, but doable with practice.
So everyone knows, I presume, what this structure is.
Your ciliary body, which is attached to your lens by your zonules.
And the zonules attach to the capsule.
And the capsule is what the lens is inside.
Who knows, how thick the capsule is posteriorly?
If you said four microns, you'd be right.
It's a mere four microns that separates you from the vitreous.
Very important to be cognizant of that.
And who knows how thick, the anterior capsule is?
It's about 14 to 21 microns.
So you are going to be manipulating, a 14 to 21 micron piece of biologic tissue.
Serious business.
The goal of capsulorhexis is to make an opening in this basement membrane.
Yes, the capsule is the basement membrane, of the lens epithelium.
And the goal is to make an opening, in that basement membrane leaving the rest of
that natural bag intact the entire case, so
that you can put the artificial lens in that natural bag.
So again, just reminding you, 4 microns separating you from the vitreous.
And 14 microns that you're going to be manipulating.
Challenging part of the case.
So the goal again is to make a nice round opening.
In the capsule so that you can insert your instruments, sort of into the bag, and
clean out the lens, and place the eye well into that bag.
What is the basic history of this manuever?
Well the first,
removal of the anterior part of that capsule was an anterior capsulectomy.
That was described by Vote many, many years ago.
And he basically just put a toothed forceps inside the eye,
grabbed the anterior capsule, and ripped out whatever came out.
And that was a definite opening in the anterior capsule.
Next came the Christmas Tree Capsulotomy, and
that was developed my Kelman and it was basically a little more
controlled triangular opening in the interior capsule.
Then came the Can-opener and
if you're old enough you probably remember doing the Can-opener,
on many a patient who was getting an extra capsule or cataract extraction.
Can-opener was multiple interconnected perforations that were fashioned in a,
a circle.
All three of these were subject to tears, because of their irregularity.
Then came the Continuous Curvilinear Capsulorhexis that was described by Gimbel
in Canada and Newhan in Germany in 1984, sort of simultaneously and independently.
This technique creates a smooth, round opening.
In the anterior capsule that is very resistant to tears because it
has a smooth margin.
So this was how, the can-opener was created.
The can-opener capsulotomy.
You just take a bent needle cystotome, and
make lots of little perforations in the capsule in a round fashion.
But the continuous Capsulorhexis makes a nice round,
smooth edged opening, very, very resistant to tears with stretch.
Which is very important.
The advantages of the curvilinear Capsulorhexis is it's mechanical and
structural integrity.
Because it stretches without tearing.
It has no flaps or tags that can get stuck in your instruments as you're aspirating,
and it gives a nice.
Space for you to put your new artificial lens into your capsular bag and if there
just by chance happens to be no posterior capsule available for whatever reason.
You've got an anterior capsule that's very strong,
strong enough to put an interocular lens in the sulcus and support it,
so you want a good anterior Capusulorrhexis.
Because you want ideal placement, especially of these lenses.
You see what type of lens this is, the multifocal lens.
It should be perfectly centered and to get that to happen,
you need a nice round opening that ideally should be about a half of a millimeter.
Smaller than the optic of your eye well, but we'll get to that in a minute.
So the ideal Continuous Curvilinear Capsulorhexis is large enough for
you to manipulate the natural lens as you're getting it out, and
large enough for you to manipulate your artificial lens once you get it in.
Like if you're putting in a torque, and you have to manipulate things afterwards.
It's small enough that the capsular margin, the anterior capsular margin,
just covers the peripheral part of the optic.
Like I said, usually around a half a millimeter or so.
So, it's usually around 5.5 to 6 millimeters, and again,
you want a continuous smooth margin.
So that you decrease the chances that it's going to tear.
So, the ideal opening you can see in this picture.
It's not the greatest picture, but it does show this overlap here.
Here's the overlap, of the anterior capsule over your optic.
And there's lots of different ways of creating this opening.
Many, many different techniques and tools that you can use.
So most people.
For at least part of the Capsulorhexis we'll use a cystotome,
which basically is this little part of this instrument, this entire instrument.
You can mount your cystotome on a metal handle, or
you can mount it on a TB syringe, like this is.
Some folks will actually do the entire Capsulorhexis.
With a bent needle cystotome.
And never use one of these, which are basically just capsular forceps.
I use a utrata, but there are other different brands of capsular forceps.
And some folks will actually do the entire Capsulorhexis with lynns forceps and
use the little point that's on the end of those forceps to make.
The first little opening in the capsule, and then drag that and
create a flap and go the whole way around just with the forceps, so many, many,
many different ways to accomplish the same task.
Some people in creating a Capsulorhexis are pushers, which
basically means they make an opening in the center, they drag and then they push.
Up a flap, so they're pushers.
So again, push up a flap and then start dragging around.
Some people are pullers.
And they'll actually make an opening, drag and then pull up a flap, and
start weaving it around.
Whatever you're most comfortable with, because no way is wrong.
And lots of options, like I said.
The basic rules of learning how to do a Capsulorhexis are.
Always re-grab the flap that you've created at the origin frequently.
Don't wait until you've got a lot of capsule torn to go back to the origin and
re-grab, because that gives the opening or the tear a chance to
propagate out into the periphery, which is not a fun experience.
You always want to use lots of OVD, OVD, OVD.
You can never have too much OVD.
That helps keep the lens and the capsule pushed back and flat.
And it helps you control your flap once you've created it.
So, don't be afraid to stop, even after you've just started the Capsulorhexis.
And put in more visual elastic.
Stay in the plane of the anterior capsule.
Don't lift up on your flap.
Keep everything down nice and low, next to the plane of the anterior capsule.
If you lift up, you're like, more likely to go radial.
We don't want that happening, but if you do there is a technique that you
can use to correct it and we'll talk about that.
And you want to lead the tear around the projected pathway of the finished opening.
So, like your kind of drawing a circle where you want the opening to be.
How can you practice this?
Well, it's easy to do with tomatoes.
Why don't you just parboil some tomatoes, boil them for
like a minute, dunk them in boiling water, then take them out and drain them.
And then you take your homemade bit needle cystotome.
You make your puncture in your homemade Capsulorhexis.
And then you either push up a flap, or
you pull up a flap, depending on whether you're a pusher or a puller.
And you just start leading it around with your forceps.
Until you've made a nice opening.
But, I didn't make a good opening because I have a little irregularity there.
So this is a good way to practice.
And then you can make yourself some bruschetta afterwards.
It's delicious.
So.
Back to the rhexis.
Usually we're working with the red reflex, to determine where our rhexis us.
That's not always the easiest thing, but
it is much easier now with a simultaneous coaxial illumination of the Lumera.
You guys have got it made now.
It was much harder a long time ago when I was a resident.
So now you actually get this incredible red reflex with the Lumera.
And you're going to watch.
Your opening being created against the red reflex.
This person, in my opinion, needs to regrasp at the origin right here,
especially if they're learning.
But, sometimes you actually aren't going to be able to see a red reflex.
And that's because the cataract is really dense.
Like this white cortical completely opaque cataract.
If that happens your going to need to use a special stain to make it
obvious where your capsule is.
So, how do you do that?
How do you use one of the special stains that we use to.
Visualize the anterior capsule when the cataract is completely opacified and
you can't use the red reflex.
You're going to create your paracentesis,
a lot of these steps you've already gone through with other lectures.
So you're going to create your paracentesis and, instead of immediately
injecting viscoelastic like you normally would if you didn't have to use a stain,
you're going to inject air into the anterior chamber.
Then you're going to take your staining substance,
which we use trypan blue usually.
And you're going to inject that sort of underneath the air at the interface,
between what aqueous is still in there in your intercapsule and
the air, and drop it right over the lens.
After you've got the lens nicely coated or
the capsule nicely coated you're going to irrigate the trypan from
the anterior chamber with BSS and then you'll proceed as usual.
Just inject your viscoelastic and clear cornea incision, et cetera.
So now that we've gone over the steps, for how to use one of the special stains we're
going to watch a little video of the special stain being used.
So as we're watching the video we'll talk about the steps again,
that we just discussed in the previous slide.
So like I said, we're going to make our paracentesis.
The small angle blade.
And then we're going to put air into the anterior chamber.
And then we'll take our trypan blue stain.
And I like to start just dropping it right over the surface of the capsule,
and once you've got the capsule nicely coated then you take some BSS on
an irrigating canula, and you irrigate that dye from the anterior chamber.
And it's amazing how much dye can get in there,
so actually just irrigate until you see.
The iris very well and you see the lens very well.
And I like getting the air bubble out so that I can see.
I don't like bubbles.
They get in the way.
Okay, now, we're putting in a viscodispersive agent.
And now, we're putting in a viscocohesive agent, so
that it have the soft-shell with the dispersive protecting the endothelium.
I don't think you need to see any more of this, do you know?
Well, actually, I'll show you where we start making the capsular opening,
with a cystotome like we just talked about.
So that you can see the difference between the stained capsule and
the totally white cataract, and how that
makes your caps are opening actually show up and help you see where your flap is.
So if you didn't do that, you would not be able to tell where the flap was because it
would be completely colorless, clear and colorless.
So that's how you use blue.
And this is what you don't want, to have happen right there.
That's an irregularity in the continuous curvilinear opening that it
was supposed to be.
And that's actually just a prime spot for tears.
And that's actually what happened in this case was a nice tear.
Why does the Capsulorhexis tend to tear if there is a tag or irregularity with it?
Well it's basically because it behaves like cellophane.
Cellophane, if there's a smooth edge is very resistant to tears.
You can prove that to yourself with a piece of gum like this.
You cannot rip this along that smooth edged surface, but
it's made with irregularities so that it's very easy to open.
So just think about the capsule, as being like cellophane.
If there's an irregularity there, it's more likely to tear.
So let's watch a little video of somebody who is a pusher in
creating a Capsulorhexis.
So they use a cystotome to push up a flap in this.
Patient who had a very dense white cataract and needed trypan blue staining.
So that is an example of a pusher.
And like I said, you can never have too much viscoelastic.
Feel free to put in lots.
And after they've pushed up a flap, they're going to use their utrata forceps
to then fashion the continuous curvilinear tear.
And I needed to regrab right there, and I should of done it sooner.
But fortunately, it was a continuous curvilinear tear.
Now let's talk about a video of someone who is a puller.
This is a YouTube video that you can watch on your own, so
that you see how someone who uses the pulling technique does it.
And if I remember correctly, this person actually leads the tear.
Tear around the entire way with cystotome.
So again, just a different way of doing it.
Whatever you feel most comfortable with will work.
This is an excellent video,
that talks about just all of the basic principles of good Capsulorhexis creation.
It's a complete video, very comprehensive.
And I think it's important to watch.
So take a minute and watch that.
So, what do you do if your Capsulorhexis starts to go radial?
It's a very scary moment in cataract surgery.
But fortunately, not too many years ago Dr.
Little described a technique that works the vast majority of times.
As long as you recognize early enough.
That's your cap, your Capsulorhexis' is starting to propagate peripherally.
You can usually bring it back to center.
How do you do that?
Once you recognize something is about to happen and you're going peripheral.
Stop and put in the scholastic,
you can never have too much OVD, and evaluate the situation.
[LAUGH] Then you want to take the flap that you've created, and
fold it back against the cortex right where it came from.
Then you're going to grasp the flap that you've made really close to the root.
Close to the, where the tear's originating now.
Then you going to pull that backward along the path that the tear was going on,
don't pull upward at all, you're going to keep down flat next to your
cortex at that point, and you're going to pull backward where the tear came from.
Then you're going to pull centrally toward the center of the lens, and
that will propagate the tear inward.
It's still stressful I get stressful just even talking about.
These were excellent pictures that were part of the paper that we
just talked about.
By Dr. Little.
And this is showing the little tear out rescue next to a white cataract, and
the capsule stained with trypan blue.
So he's, or she, whoever's doing the surgery is feeling that they're getting
a little too close to the periphery, so they're going to take their flap and
lay it back down where it originated from.
And pull a little backward, and then pull centrally.
So you're going to pull back, and then you're going to pull centrally.
And it obviously brought the tear inward.
And then this is the same sort of technique, but
done against the red reflex.
And I would wholeheartedly agree that this is way out in the periphery, so.
He's going to pull back and now he's already pulling down towards center, and
down here towards center again and it clearly brought the tear back inward.
So, this is a wonderful technique that I didn't know too much about as a resident
and it would have made things a whole lot stress, or a whole lot less stressful.
But now you get to be the benefactor of this great information.
So, this is also a YouTube video of someone doing a little tear-out rescue,
a multitude of times.
And, someone who's got a really [INAUDIBLE] white cataract.
So, in those situations where the lens is really, really big, fat and swollen.
The capsule is much more likely to go radial than otherwise.
And so he uses a little tear out rescue many, many times during the creation of
his Capsulorhexis, so very good video to watch as an example of how to perform.
So that's everything you need to know about Capsulorhexus creation,
you can call me if you have any questions, it was great to talk to you.
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