Microinvasive glaucoma surgery (MIGS) is a game-changer for many patients, often freeing them from the need to use multiple eye drops every day to manage their disease, and MIGS is steadily gaining acceptance among ophthalmic surgeons.

“Microinvasive glaucoma surgery is one of the fastest growing sectors in all of ophthalmology in terms of investment, and the data we’ve seen from Market Scope and other sources over the last several years is compelling,” says refractive cataract surgeon Blake K. Williamson, MD, Baton Rouge, LA. “I think cataract surgeons now understand that not only can they help patients see better and reduce their need for glasses after cataract surgery, but for some patients with glaucoma, they can place a stent or perform a procedure that can help reduce their medication burden, too.”

According to New York cataract and glaucoma surgeon Nathan M. Radcliffe, MD, MIGS is steadily gaining acceptance among ophthalmic surgeons, and with its safety and efficacy established, it’s a good fit for the ASC setting.

We asked both surgeons to share their insights for MIGS efficiency, starting with pre-op decisions.

Avoid Reimbursement Pitfalls

Both surgeons emphasize that choosing a MIGS device or procedure for a specific patient requires more than interpreting diagnostic test results and analyzing a patient’s disease state. A misstep in preoperative planning — implanting a device that’s approved for use only during cataract surgery for a patient who’s already had cataract surgery, for example — is just one potential pitfall.

“Pairing the correct MIGS device to the appropriate patient involves more than determining how severe the glaucoma is or how much efficacy we need,” Dr. Williamson says. “In addition to a clinical examination, we need to do an insurance examination. We must make sure we’ll be reimbursed for what we do, or we’ll be left holding the bag, particularly surgeons who own ASCs.”

Dr. Radcliffe encourages bidirectional communication between the ASC administration and the surgeons regarding coverage issues. “Occasionally, a surgeon won’t know that some MIGS procedures aren’t covered by particular insurance carriers, and that can create financial problems for the ASC. Timely communication can avoid these issues.”

Prior authorization is key to ensuring appropriate reimbursement.

“For all of our carriers, even if we know they typically cover the procedure we’re planning, we call for prior authorization,” Dr. Williamson says. “It’s also important to look at how payers are reimbursing for MIGS. Even though they say they will reimburse you, be aware that for certain devices, the facility fee they are providing as ‘reimbursement’ may not cover the cost of the device in the ASC.”

Dr. Radcliffe agrees. “Prior authorization protects the ASC,” he says. “If a particular stent is not covered, the surgeon will be paid less for sure, but the ASC, which may have purchased a $1,300 stent out of pocket, will not be reimbursed and may take a loss.

“It’s also worth mentioning that procedural MIGS, including goniotomy, canaloplasty, and endoscopic cyclophotocoagulation, has a Category 1 CPT code and tends to have nearly universal coverage,” Dr. Radcliffe says. “Whereas, the MIGS implants have T Codes and are more likely to have coverage gaps.”

As far as OR time utilization is concerned, Dr. Radcliffe notes the facility fee tends to be appropriate to cover the implants or instruments, OR time, and supplies without major disparities between MIGS procedures.

“While there are many MIGS procedures, I don’t think there are truly significant differences in how long it takes to execute a specific procedure that would have a big impact on the ASC’s preference for which MIGS procedure is performed,” he says. “In other words, I don’t think you need to choose one procedure over another because of OR time utilization.”

3 MIGS-Specific Things You’ll Need in the OR

OR preparation for a MIGS-cataract case, although not vastly different from a cataract case, requires specific direction from the surgeon and forethought on the part of the OR staff.

“Depending on which procedure is being performed, the surgeon will need the appropriate implant or instrument along with a gonioscopic lens,” says Dr. Radcliffe. “The implants are the Hydrus Microstent (Ivantis), the iStent and iStent inject (Glaukos), and the Xen gel stent (Allergan). The instruments tend to be the Kahook Dual Blade (New World Medical), the Omni device (Sight Sciences), and the iTrack (Ellex).”

The third thing needed for MIGS is viscoelastic, but as Dr. Radcliffe explains, this may not be the same viscoelastic the surgeon usually uses in cataract surgery.

“It’s important to verify the surgeon’s preference for viscoelastic during the MIGS part of the procedure,” he says. “And be aware that the surgeon may prefer one viscoelastic for one type of MIGS and another viscoelastic for a different MIGS procedure.”

Prepare for Increasing Volume

Surgeons who are just starting to perform MIGS in the ASC will likely begin slowly. As volume increases, which can happen rather quickly, maintaining sufficient and appropriate inventory will be a priority.

“Inventory management is important, particularly as surgeons ramp up their MIGS volume, because it’s not uncommon to get caught off guard,” Dr. Radcliffe says. “You may have been ordering 10 stents every week, and the next thing you know, you need 20 stents. You need to monitor your usage and adjust orders appropriately. Additionally, you should have a system in place to review the number of cases you have coming up to make sure you have enough inventory to cover them.

“Similarly, the ASC should also be aware that occasionally a surgeon will switch from one MIGS device to another,” Dr. Radcliffe says. “When that happens, you have to react quickly and stop ordering that device. Otherwise, you end up being in possession of 100 MIGS devices that won’t be used. You need to keep a tight control of your inventory.”

Another issue that can affect efficiency is the need for a gonioscopic lens for each case. Again, a rapid increase in volume can create a situation that adds to your surgery time.

Dr. Radcliffe explains: “For my first iStent case 7 years ago, I implanted one stent. After about a month, I was implanting four or five stents per day, and we noticed that after a few cases, our gonioscopic lenses were still being sterilized when we were ready for the next surgery.

“I don’t think you need to be concerned about how these cases are scheduled in the day, except to be aware that if you have five gonioscopic lenses and you have seven cases that will require one, you should leave enough time between cases to resterilize instruments. Another solution is to have disposable gonio prisms on hand. You may not use them routinely, but if you find yourself in a situation where you don’t have any instruments available, they can be a lifesaver.”

Optimize Visualization

“More than in just about any other anterior segment surgery, MIGS depends on exquisite visualization for successful outcomes,” Dr. Williamson says. “You cannot treat what you cannot see.”

Dr. Williamson notes the gonioscopy examination in clinic provides key information for MIGS, including visualization needs. “The gonioscopy examination is one of the unsung heroes of our ophthalmology workup,” he says. “We need to be looking in the angle to determine what we may need in the OR. For instance, the exam may reveal a very lightly pigmented trabecular meshwork, indicating the need for trypan blue.

“Or maybe a patient was referred to your practice, and you see he is pseudophakic. The patient reports having had cataract surgery but nothing else. Upon gonioscopy, you see an iStent, which may change your approach to that particular case.”

Dr. Williamson notes that some surgeons who perform combined MIGS-cataract surgery prefer to place the MIGS device before addressing the cataract. “They do this because they feel they have the most pristine view of the angle, and, because MIGS is a minimally traumatic procedure, bleeding is negligible,” he says.

Another visualization tip from Dr. Williamson involves the use of the gonioscopy lens in the OR. “Make sure you’re not exerting too much pressure on the gonio prism onto the cornea, because that will cause corneal folds, and corneal folds will cause you to lose your view,” he says. “If you lose your view all of a sudden, you’ll become frustrated, the case will go longer, and complications may arise. You need a good view to be safe and efficient.”

Dr. Radcliffe notes, “To visualize the drainage angle for MIGS, you must turn the patient’s head to the side and tilt your microscope. A microscope that allows you to adjust the tilt with the foot pedal is most efficient, but if you don’t have such a microscope, you must adjust it manually, which takes a couple of minutes. If you typically tape a patient’s head to keep it still for cataract surgery, you should think ahead about how you’ll release the tape for the MIGS procedure, or perhaps consider not taping” (See “A Surprising Tip for Surgeons”).

A Common Complication

Dr. Radcliffe emphasizes the need to obtain proper consent from patients who will undergo a MIGS procedure, noting specifically that bleeding is slightly more common with these procedures.

“Bleeding is the most meaningful complication encountered during MIGS procedures and managing this complication can affect OR time,” he says. “Blood reflux occurs after MIGS when the pressure in the eye is lower than episcleral venous pressure; the bleeding has nothing to do with coumadin or aspirin use. To prevent reflux bleeding, the surgeon may do well to keep the eye highly pressurized. Having the OR staff place the patient in a more heads-up posture — so the heart is above the feet — is helpful.”

Growing Acceptance

“Most but not all surgeons are doing something along the MIGS line,” says Dr. Radcliffe. “But there still are surgeons who are not treating any glaucoma along with cataract surgery, so there’s still room to grow.”

Dr. Williamson urges his colleagues to add MIGS to the cataract conversation and participate in the evolution of the standard of care. “At this point, standard of care for glaucoma patients with cataracts is rapidly becoming MIGS at the time of cataract surgery,” he says. “There are many devices out there, and it’s easy to become overwhelmed. Just pick one. I always tell surgeons that the best MIGS device is the one that you do the best.”

According to Dr. Radcliffe, “We are approaching a day when roughly 20% of cataract patients who have glaucoma will be receiving a MIGS procedure at the time of their cataract extraction. This procedure has been and will continue to be efficiently incorporated into the ASC environment in a successful manner.” ■