July 2019

IN FOCUS

MIGS Update
Complications in MIGS


by Ellen Stodola EyeWorld Senior Staff Writer/Meetings Editor





Intraoperative hyphema during insertion of an OMNI Glaucoma Treatment System
Source: Thomas Patrianakos, MD

At a glance

• Hyphema and blood reflux are two complications that can occur with MIGS procedures. These tend to resolve on their own.
• More serious complications can include cyclodialysis or Descemet’s detachment.
• Other MIGS “complications” could be connected to gaining familiarity with the procedures or the devices being less efficacious in some patients.

“While each MIGS has its own possible complications, we as surgeons continue to modify our technique to minimize these and to better manage them when they arise.”
—Thomas Patrianakos, MD


Though MIGS is generally considered safer than traditional glaucoma procedures, complications can still occur. Two surgeons discussed potential complications, how to speak to patients about them, and how to remedy these situations.

Jacob Brubaker, MD

One point that Dr. Brubaker said he is sure to mention to patients is that sometimes these devices are not effective for some people. It’s important to make sure patients are aware upfront that the collector systems may not function in a particular individual. “We’re not aware of that until we’re doing surgery,” he said. As a result, a common “complication” may be that it’s just less efficacious in some patients.
Dr. Brubaker said that one of the most common surgical complications that can occur is bleeding. This is more likely with trabecular bypass ablating procedures.
In procedures like the Kahook Dual Blade (KDB, New World Medical) or gonioscopy-assisted transluminal trabeculotomy (GATT) or OMNI Glaucoma Treatment System (Sight Sciences), there is a common hyphema risk, he said. Depending on how much you excise, with KDB, you may have around a 5–10% chance that there will be a little hyphema, he said.
Dr. Brubaker has seen hyphema in some iStent (Glaukos) cases that may take up to 2–4 weeks to resolve.
Dr. Brubaker also noted that although the CyPass (Alcon) is no longer being implanted, it could be associated with such issues as hypotony, myopic shifts, uveitis, and endothelial cell damage.
Rare complications such as iridodialysis, cyclodialysis, or Descemet’s detachment can occur, Dr. Brubaker said. Descemet’s detachment may be seen more commonly with incisional procedures. The trabecular meshwork may be more adherent to the endothelium, he said, and it could detach as you ablate or remove it. It’s important to recognize this early and cut it rather than continuing to pull.
Though many associated MIGS complications will resolve on their own, Dr. Brubaker said they may need some sort of intervention. If there is cyclodialysis or iridodialysis, that will often need repair, he said. Hyphema will usually resolve on its own.

Thomas Patrianakos, MD

MIGS in general is meant to be safer and have fewer complications than traditional glaucoma filtration surgery, Dr. Patrianakos said. He stressed that these procedures are not complication-free, but they don’t see complications as frequently.
One of the first issues he discussed was gaining familiarity with the procedure. Since they’re all relatively new, these procedures are either self-taught or someone from the industry works with surgeons to train them on the product. Training may also include watching videos.
“Being familiar with intraoperative gonioscopy is essential to minimize complications,” Dr. Patrianakos said, adding that being familiar with angle structures is also important.
To make these procedures safer and have a better target in terms of outcomes, make sure you have a clear view of the angle before proceeding with any of the devices that use gonioscopy, he said.
One cause of complications in MIGS procedures is blood reflux. “If your view is not crystal clear, then you’re not going to be able to perform the procedure correctly,” he said.
To handle blood reflux, Dr. Patrianakos suggested using viscoelastic, “your best friend when it happens.” Make sure you push the blood away, he said, and be sure to use it as frequently as needed to ensure a good view.
Putting the patient in a reverse Trendelenburg position can decrease episcleral venous pressure and can also be helpful in reducing blood reflex intraoperatively. It is also essential to minimize trauma to the iris or ciliary body, as this can cause additional bleeding.
If possible, consider stopping anti-coagulation preoperatively, Dr. Patrianakos said. This requires consulting with the primary care physician to see if it’s a plausible option.
Finally, he added knowing “when to abandon ship” is important. If you’re doing a procedure and there’s a constant reflux of blood that keeps coming despite all efforts to impede it, it may be best to stop. Consider transferring to another site or revisiting the surgery on another day.
“In general, when I consent patients for these procedures, my consents mimic that for cataract surgery,” he said. “We are making an incision in the eye, so there’s a chance of infection, pain, bleeding, and a need for another surgery.”
He warns patients that there may be fluctuations in IOP that need to be dealt with early, though they tend to even out.
“I also warn them about the possibility of decreased vision on postop day 1 depending on blood reflux,” he said. Although MIGS mimics cataract surgery, there are other considerations because he wants patients to know that it’s more than just removing a cataract. You have to adjust for the pressure, and vision may not be as clear postop day 1 as with traditional cataract surgery.
More serious complications that can occur include cyclodialysis and Descemet’s detachment, Dr. Patrianakos said, and the best way to avoid them is to ensure that you have a crystal clear view of the angle when performing surgery. A cyclodialysis cleft may occur by inserting an iStent in the wrong position or by doing GATT where you could inadvertently create this.
Procedures that require ab interno viscodilation of Schlemm’s canal have a risk of developing a Descemet’s tear, if you inject viscoelastic too vigorously. Dr. Patrianakos said that if the tear is superior, the surgeon can leave it and use an air bubble to push Descemet’s back into place. Even in other locations, he said the tears tend to be more peripheral and don’t affect visual acuity much.
“While each MIGS has its own possible complications, we as surgeons continue to modify our technique to minimize these and to better manage them when they arise,” he said. This ultimately provides a safer alternative for patients than more invasive traditional glaucoma procedures.

Contact information

Brubaker
: jacobbrubaker@me.com
Patrianakos: tpatrianakos@yahoo.com

About the doctors

Jacob Brubaker, MD
Sacramento Eye Consultants
Sacramento, California

Thomas Patrianakos, MD
Cook County Health
Northwest Chicago
Eye Specialists
Chicago

Financial interests

Brubaker: New World Medical, Ivantis, Glaukos
Patrianakos: None

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