Part 14 of 14 of “Adjusting the Faucet or Opening the Drain – Currently Available Methods to Treat the Plumbing Problem of Open Angle Glaucoma” | A San Gabriel Valley Optometric Society (SGVOS) Continuing Education Dinner Event – 2 hours CE | Featured Speaker: Dr. David Richardson, MD | April 12, 2017
Canaloplasty with Stegmann Canal Expander
This is the one I’m most excited about and I think you’ll see why.
We’ve been talking about minimally invasive glaucoma surgery and the problem with it; potentially, being minimally effective specially when you compare it to cataract surgery. So Dr. Stegmann, who created Canaloplasty thought, “this is great stuff but can we make it better?” And so, in terms of what we just talked about—with the Hydrus as a scaffold from the inside—If that will…“can I create a scaffold that can be used with canaloplasty?” So he created this tube-shaped scaffolding device that’s placed in Schlemm’s canal and can keep —and this is the key: the Hydrus and these other scaffolds are very, very small (only a few clock hours). In the case of this device, it can keep—up to half the canal open permanently. And this video (I think) is worth seeing.
Video: Stegmann Canal Expander by Dr. Matthias Grieshaber
And this is by Dr. Matthias Grieshaber, who is an outstanding glaucoma surgeon (overseas). And you can see, this is actually—he’s already done the canaloplasty. He’s pulled the catheter back and you saw the viscoelastic gel at the end of it. So he’s dilated the canal. Now here is this stent. You can see it’s a pretty long stent. What he’s going to stent is on… it’s essentially a guide wire. So what he’s going to do is he’s going to thread this guide wire back through the dilated canal and now you can see at the end of this guide wire is this stent – he’s going to place this stent, again using the guide wire to help it move along. He’s going to move this into the canal. Now this is such a long stent that he wouldn’t be able to do this without the guide wire. And now he’ll pull the guide wire out, holding on to the stent, and then once this is done he’ll then do the same thing on the other side but then close up as he would any canaloplasty.
So is it successful? It certainly looks like it should be.
Well, we now have two year results and if we look at the success—recall earlier, I was talking about success rates with the different minimally invasive glaucoma surgeries in terms of the percentage of patients who had pressures at or below 20-21mmHg—the problem with these studies, of value is kind of a different outcome but if you recall those compare that to this:
For those had a final intraocular pressure of less than or equal to 21mmHg, there is a 98% success rate. Almost a 100% of those who had the surgery had a final pressure of <= to 21 mmHg. That is absolutely outstanding! And if you you want to lower the threshold make it more challenging, <=18 mmHg almost 90% … so, 88%. And if you dropped it even further, <=16 mmHg, it did an 86% success rate. That is unheard of for a procedure with the safety profile of Canaloplasty. And the Stegmann Canal Expander did not significantly increase the risk over and above what one would expect from Canaloplasty.
How does the “gold standard” of trabeculectomy compare?
And here’s the key slide I want to show you because we’ve started out talking about medications and the fact that all of these medications have risks and side effects and issues that bother our patients.
We moved into surgery—the penetrating surgeries that have been around for over 50 years (a half a century) with all of the risks. And we said, “well the problem is nothing’s as good as Trabeculectomy”. The Holy Grail is to get a safer procedure that is as effective as Trabeculectomy. And if we look at the two-year study result of the “Trabeculectomy Versus Tube Study”, which is the one of the most commonly referenced studies looking at the outcome of Trabeculectomy and we compare that with a two-year results of the Canaloplasty with Stegmann Canal Expander… Let’s take a look at this. Initial IOP in this two studies (the TVT studies again). Trabeculectomy 25.6, the Canaloplasty 26.8 (so similar starting).
Final IOP – 12.1mmHg in the TVT for Trabeculectomy, 13.3 for this Stegmann Canal Expander with Canaloplasty – 1mmHg of difference.
We can also look at Percent Reduction (of IOP) – 52.7 in the Trabeculectomy, 50.4 with Canaloplasty with Stegmann Canal Expander. Initial glaucoma medications – 3 in Trabeculectomy, 2.8 on Canaloplasty with Stegmann Expander (again, very similar). Final number of glaucoma medications – 0.8 with Trabeculectomy and 0.2 with Canaloplasty with Stegmann Expander. And if we look at the percent reduction of medication use – 73% with Trabeculectomy, 93% with Canaloplasty with Stegmann.
So it is—at least based on this comparison (one can feel pretty confident that this is), not inferior. Not significantly inferior to Trabeculectomy in terms of pressure reduction. But in terms of safety profile and the limitations that one would have to place on the patient, there’s no question that Trabeculectomy is the loser here and Canaloplasty with Stegmann Canal Expander is the winner. Now the only issue here is that unlike the other things I’ve shown you in the pipeline, this Stegmann Canal Expander is much further out.
So the best we can get today with this is that Canaloplasty alone. We don’t yet have (and will probably not have for quite a few years if ever—depending on the FDA and what they decide) have this (Stegmann Canal Expander) but i am so incredibly hopeful that we will get that because i think that is the minimally invasive glaucoma surgery that is also maximally effective.
Presentation Closing Remark
So, a lot of interesting stuff coming down the pipeline. Of course, what we get and what we can just kind of look overseas and wish we had is something that we won’t know and it’s out of our control. (But you know) hopefully I’ve at least introduced a couple of new things to those of you and refresh your memory on some old things. And I’m going to open it up for questions and any questions that don’t get answered today this afternoon, please feel free to give me a call or an email. I’ve put—that’s my office number there and my email, but I’m also willing to give out my cell phone number to anybody who would like to call me personally.
Alright, thank you.
Currently Available Methods to Treat Open Angle Glaucoma Series:
- Currently Available Methods to Treat Open Angle Glaucoma
- Beta-blockers, Selective Alpha Adrenergic Agonist, CAIs
- Prostaglandin Analogs, Cholinergic Receptors Agonists, Fixed Combination Agents
- Carbonic Anhydrase Inhibitors (CAIs)
- Laser Trabeculoplasty
- Continuous Wave and Micropulse® Cyclophotocoagulation
- Trabeculectomy and Glaucoma Drainage Devices
- Ab-Externo Canaloplasty
- Ab-Interno Canaloplasty
- IStent®, Cypass® Microstent, Xen® 45 Gel Stent, Cataract Surgery
- Next-Generation Glaucoma Medications and Surgeries
- iStent Supra®, Hydrus™ Microstent, and InnFocus MicroShunt®
- Canaloplasty with Stegmann Canal Expander