Ab Interno Canaloplasty for Glaucoma


So moving on to the minimally invasive glaucoma
surgeries, which is really an exciting area right now—but the question is, “are they
also minimally effective?” So the ones we’re going to go over are the
ones that are FDA-approved: Ab-interno Canaloplasty (ABiC)—so this is Canaloplasty from the
inside of the eye, Trabeculotomy, iStent®, Cypass®, Xen Gel Stent, and Cataract Surgery. And you may say, “well, why’s cataract
surgery up there?” We will get to that. So interestingly enough, with the Ab-Externo
Canaloplasty (coming from the outside) they separated the results in those that had the
stent and those that didn’t have the stent. And what they saw was that, although they
generally did better with the stent (even if you couldn’t get the stent in) the pressure
is still dropped. And you can see in this here three-year results
of those with Ab-Externo Canaloplasty but without the suture the average pressure dropped
from 25.2 mmHg to 16.2 mmHg. This is a pretty decent reduction and the
mean number of medications from 2.1 to 1.1— so by one medication on average. So, Dr. Mark Gallardo in El Paso Texas thought,
“well this is interesting. Is there a way that we could do this from
the inside of the eye without making the incision from the outside the eye, which would make
it much less complex of a surgery and also a much faster surgery. And it turns out you can and the neat thing
about it is that by doing this you treat the trabecular meshwork—because you create an
opening in the trabecular meshwork, you open Schlemm’s canal, you potentially dilate
the collector channels— so you get better aqueous outflow, and there’s no permanent
stent or implant. And that’s the key point of the Ab-Interno
Canaloplasty— no permanent stent or implant. What we’ll do here is I’m going to take
us through—this here, so essentially this is after cataract surgery. So, what’s going to be done is— you can
see over here that…here’s—the catheter is being inserted into the anterior chamber
and it’s basically being rested against the angle here. Then what happens
is a gonio lens is placed on the eye—and here again you can see that the catheter is
resting there so you’re looking at the angle of the eye—and either a blade or Cystitome
is used to actually pierce the trabecular meshwork, opening up into Schlemm’s canal,
which also—which often results in a little blood reflux—so you can see a little blood
there. And then this is what is so cool about this
procedure—micro forceps are used to thread this catheter through and you can see the
tip of the catheter (it’s a blinking red catheter), you’re going to see it coming
around here in a moment—so these—he’s threading it around to the Schlemm’s canal. So he’ll thread it all the way around and
then place another instrument in the eye to essentially hold the catheter up against the
angle and he pulls it back through. As it’s being pulled back through, viscoelastic
is being injected into the canal—dilating the canal. So how does it work? Well, the initial studies, looking one year
out basically showed—there’s two: one was by Dr. Khiami, showed a reduction of from
19.5mmHg to 13.9mmHg. The reduction of average medications from
2 to 0. Dr. Gallardo, showed a reduction of 18.6mmHg
to 12.9 mmHg. You get 12.9 mmHg! I mean, that is in the range of what the Trabeculectomy
studies are showing, right? And mean reduction from 2 medications to 1. And if you actually combine the studies—mean
IOP from 19 mmHg to 13.3 mmHg, 2 meds to 1. You know these are very impressive results
for very safe and very fast surgery.

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