GLAUCOMA IN THE ASC
PART 1 IN A SERIES

Glaucoma in the ASC

Best practices for combined cataract-glaucoma procedures

By Desiree Ifft, Contributing Editor

For many years, surgeons have been combining lens removal/IOL implantation with trabeculectomy or tube shunt placement for patients whose coexisting cataract and glaucoma required both procedures. Newer, less invasive surgical options for glaucoma, developed with the goal of lowering IOP with fewer potential complications than traditional procedures, can be combined with cataract surgery as well. Most recently, the availability of the iStent trabecular micro-bypass device (Glaukos), the first minimally invasive glaucoma surgery (MIGS) device approved in the United States, has renewed interest in the combined cataract and glaucoma surgery option.

Advantages of Combined Surgery

Because a combined cataract-glaucoma surgery is one trip to the OR and one recovery period instead of two, it’s an opportunity to increase convenience while reducing costs and exposure to anesthesia for patients. It’s also an opportunity to achieve lower IOP than would be reached after cataract surgery alone and to reduce or eliminate a patient’s dependence on topical glaucoma medications. “Furthermore, a patient with moderate to advanced glaucomatous disease might suffer adverse consequences due to an IOP spike following cataract surgery alone, a complication that is largely avoidable by combining it with an IOP-reducing procedure,” says Jeff Maltzman, MD, FACS, who specializes in cataract surgery and the medical and surgical management of glaucoma with Fishkind, Bakewell & Maltzman Eye Care and Surgery Center in Arizona.

When deciding whether to perform a combination versus standalone cataract and glaucoma procedures at different times, Dr. Maltzman bases the decision on both the degree of glaucoma and the specific needs and desires of each patient. “In some cases, the primary impetus for surgery is the cataract,” says Dr. Maltzman. “Fairly good data exist showing that cataract surgery alone in patients with open-angle glaucoma often achieves a modest reduction in IOP, an average of 2 mmHg and perhaps more when baseline IOP is higher.^1-3 If a patient’s glaucoma is not severe, and if I feel he can tolerate a short IOP spike, then cataract surgery alone may be the best option, and we may be able to avoid additional glaucoma procedures completely.

“If the primary concern is glaucoma and the patient is phakic, I generally prefer to remove the lens at the time of the glaucoma procedure, assuming there is at least some degree of cataract. There are several reasons for this. First, deepening the chamber by removing the lens may facilitate a filtering procedure, often allowing me to avoid an iridectomy when performing a trabeculectomy, or permitting more posterior placement of a tube in the anterior chamber, decreasing the risk of corneal injury. Second, the inflammation caused by subsequent cataract surgery may have an adverse effect on the function of a filtering bleb or tube shunt, leading to elevated IOP. Third, a cataract may progress more rapidly following a filtration procedure, and removing it at the time of glaucoma surgery will prevent a return to the OR in the not-too-distant future.

“Of course, the safety profile of MIGS makes it ideal to consider in combination with cataract surgery. If I believe strongly — based on severity of disease, intolerance of medical therapy, or difficulty affording ongoing use of medications — that a patient would be best served by a combination procedure with MIGS or otherwise that could lower IOP more than cataract surgery alone, we discuss the options at the time of the cataract evaluation.”

Priya Desai, MD, MBA, a cataract and glaucoma specialist with Matossian Eye Associates (New Jersey and Pennsylvania), takes a different approach for patients who have fast-progressing or severe glaucoma. “My number one criteria for choosing combination surgery is that the patient has a visually significant cataract,” she says. “However, in a case that fits that criteria, but vision loss from severe or quickly progressing glaucoma is the main concern, I tend to perform standalone trabeculectomy or tube shunt. I find this increases the success rate of the glaucoma surgery because one procedure rather than two produces less inflammation and less chance of scarring. With the glaucoma under control, I can go back later to remove the cataract, at which time I may also revise the glaucoma procedure by lifting scar tissue or needling the trabeculectomy bleb.”

Which Combination for Which Patients?

Once the decision is made to perform a combined cataract-glaucoma surgery, the choice of glaucoma procedure is based primarily on the severity of the patient’s glaucoma and the target IOP. “The anticipated IOP reduction from a combined procedure is largely similar to that of the glaucoma procedure alone, though in some cases — particularly non-filtering procedures such as canaloplasty or MIGS — there appears to be a slightly greater effect by combining it with cataract extraction,” Dr. Maltzman says. “In my hands, the reduction with the iStent is generally limited to several millimeters of mercury, though occasionally a patient will experience a more significant response. My experience with canaloplasty is limited, but I’ve found that it tends to result in IOP that is anywhere from the low to high teens. With trabeculectomy or a tube shunt, pressures in the single digits or low teens can be achieved.”

Based on those expectations, says Dr. Maltzman, the iStent is a good choice in cases of relatively mild, stable glaucoma that is well controlled on one or two medications. “It may lead to better IOP control with fewer medications, saving the patient money as well as reducing potential medication-related side effects and issues with adherence to therapy.”

For slightly more advanced disease, such as mild visual field deficit and higher IOP, Dr. Maltzman may choose a non-penetrating canal-based procedure, such as traditional or ab-interno canaloplasty (iTrack; Ellex iScience Inc.), which avoids the possible complications of a filtering bleb or tube shunt while achieving greater IOP reduction than an iStent procedure. He notes, “By performing canaloplasty internally, I avoid any manipulation of the conjunctiva, sparing it for possible later filtration surgery.” Dr. Maltzman reserves trabeculectomy or drainage device procedures for cases of advanced disease, which require very low post-operative IOP. In most cases, he utilizes a modified trabeculectomy using the Ex-Press Glaucoma Filtration Device (Alcon), which he finds allows for a more controlled procedure and smoother post-op course, especially for patients who have a higher risk of bleeding or post-op inflammation. “The IOP-lowering benefit may wane after 2 or 3 years, but the benefits of the Ex-Press procedure⁴ make it a worthwhile option, in my opinion,” he says.

Often as part of clinical trials, Steven Vold, MD, glaucoma and cataract specialist and founder of Vold Vision in Arkansas, has performed many of the newest surgical procedures for glaucoma. For patients with mild to moderate open-angle glaucoma, the procedure he combines most frequently with cataract surgery is iStent implantation. Alternatively, he may consider other procedures for this group, in particular if the iStent isn’t covered by a patient’s insurance, such as cataract surgery plus endocyclophotocoagulation (Endo Optiks), internal viscocanalostomy (VISCO360, Sight Sciences), or ab interno trabeculotomy (TRAB360, Sight Sciences, or Trabectome, NeoMedix). “These procedures, combined with cataract surgery, are capable of reducing IOP by 20% to 30%,” he says.

The likelihood that patients can reduce or eliminate the need for IOP-lowering drops after surgery depends largely on which glaucoma procedure they undergo. The goal with trabeculectomy or tube shunt is zero medications, which Dr. Desai says she can achieve in more than 80% of her cataract-glaucoma surgery patients. “Tube shunts are harder to titrate, so the percentage is somewhat lower for those patients,” she says. “With iStent, 40% to 50% of my patients can decrease the number of drops they use by one or two. Even if we can’t discontinue a drop, the IOP is usually better controlled, which is a nice extra cushion the iStent can give you.”

Contraindications and Potential Complications

Reasons to avoid a specific type of glaucoma surgery at the time of cataract surgery are generally the same reasons to avoid it as a standalone procedure. For example, Dr. Maltzman notes, “I avoid canaloplasty in patients who have undergone prior filtering procedures or who have significantly narrow angles or scarring in the angle, as 360-degree passage of the catheter may be challenging or impossible.”

Potential complications generally are also the same for combined versus standalone procedures, although combined procedures can present a few unique challenges. “Cataract extraction may be complicated by factors related to the glaucoma,” Dr. Maltzman explains. “For example, pseudoexfoliation syndrome often presents with both a small pupil and weak zonules, which may require use of a pupil expansion device and definitely requires meticulous hydrodissection/hydrodelineation and gentle lens manipulation to avoid undue zonular stress. Additionally, capsular tension rings, possibly suture-fixated, may be needed to maintain centration of the IOL and prevent vitreous from presenting around broken zonules and interfering with a filtering procedure. In patients with iris neovascularization or significant posterior synechiae, care must be taken to avoid excessive bleeding or post-operative inflammation due to iris manipulation, as this may affect the viability of a filtering procedure.”

Successful iStent Placement

Steven Vold, MD, offers some pearls for successfully placing the iStent trabecular micro-bypass device (Glaukos), which is indicated for use in conjunction with cataract surgery in the United States:

Examine the anterior chamber angle carefully before surgery. Understanding the patient’s angle anatomy is crucial to iStent surgical success.

Handle the loaded iStent insertion device with care. I remove the apparatus from the packaging myself and make a significant effort to avoid hitting the iStent on the corneal wound.

Tilt the microscope toward you and the patient’s head away from you by 30 to 45 degrees to allow for good angle visualization utilizing a Hill lens or a modified Swan-Jacob lens. Use of the Transcend Vold goniolens reduces the need for microscope and patient head tilt to achieve proper angle visualization.

Left-directed iStents require a forehand motion for proper device placement by a right-handed surgeon. A forehand maneuver is generally easier for most novice iStent surgeons.

Approach the trabecular meshwork with the iStent at an approximately 15-degree angle. Once the stent is in Schlemm’s canal, flatten the approach to allow the device to slide into the canal.

Gently depress the corneal wound, which commonly causes blood reflux into the canal, to allow for easy anatomy identification. Blood reflux after iStent placement assists surgeons in determining proper device placement.

Seat the iStent securely along the outer wall of Schlemm’s canal, using the inserter or I/A tip. Regrasping the iStent to ensure the device is in proper position is sometimes required.

Place the iStent near larger collector channels in a nasal quadrant if possible.

Utilize and remove a cohesive viscoelastic with iStent placement to prevent post-operative pressure spikes.

Lotemax (loteprednol, Bausch + Lomb) is an excellent perioperative steroid that may help to prevent post-operative pressure elevations.

Be especially aware of three aspects of implanting the iStent: 1) the tip at the trabecular meshwork; 2) lifting up on the wound or depressing down on the wound, which can cause loss of visualization; and 3) relaxing your hand to relieve lateral forces before depressing the trigger to release the iStent in a controlled manner.

Dr. Maltzman also notes that MIGS procedures require the surgeon to be comfortable using a surgical goniolens and able to identify angle structures with ease. “Surgeons new to these procedures can practice by physically identifying angle structures intraoperatively using a Sinskey hook,” he says.

Impact on ASC Operations

Drs. Maltzman, Desai, and Vold perform their cataract-glaucoma combination surgeries in an ASC. They rarely take a case to the hospital, typically only when a patient’s overall health is unstable. ASCs that focus on high-volume cataract surgery may need to make adjustments to accommodate combined cataract-glaucoma procedures. Adding a tube shunt or trabeculectomy to the cataract surgery can require 15 to 30 more minutes, depending on the surgeon and the specifics of the case. An iStent can typically be placed in approximately 5 minutes following the cataract procedure. “The majority of that time involves repositioning the patient’s head and the operating microscope for the best view of the anterior chamber angle, and then positioning the head again for viscoelastic removal,” Dr. Desai says. OR prep and turnover times can be slightly longer for combined procedures as well because additional instrumentation or supplies, for example, sutures, nontoothed forceps for handling conjunctiva, a needle or blade for creating an Ex-Press entry tract, or Mitomycin-C, may be required. To maintain an efficient flow, many facilities find it helpful to schedule combination surgeries at the end of the day, after the routine cataract surgeries are complete.

Efficiency is crucial not only for a smooth daily patient flow, but also for the financial viability of combination surgeries in the ASC, as glaucoma surgery in general is typically less profitable for a facility than cataract surgery. “You can make it economically viable, but you have to be efficient,” says Dr. Vold, who is the sole owner of his ASC. Of the 1,250 surgeries he performed there in 2014, 250 were combined cataract-glaucoma, 150 were glaucoma only, and the remainder (850) were cataract only. He performs up to 20 combined procedures each surgery day and offers these tips for better efficiency:

• Use as few instruments as possible

• Never take your eyes away from the microscope during surgery

• Don’t talk while operating

• Be conscious of an economy of hand and arm movement (in other words, have every step thought out before you go into surgery, and be intentional about every motion).

Having a scrub tech who is familiar with glaucoma procedures is also important for efficiency, Dr. Maltzman says. “It’s very helpful if he has the ability to visualize under the microscope to carry out tasks, such as holding conjunctiva or the scleral flap during trabeculectomy, or retracting extraocular muscles during certain tube shunt procedures.” (Read more about efficiency and profitability with glaucoma surgery in a future article in this series.)

In addition to efficiency, surgeons and ASCs are currently concerned with two recently emerging reimbursement issues — the CMS elimination of separate payment for patch grafts used in tube shunt surgery, and the CMS bundling of Mitosol (Mitomycin-C, Mobius Therapeutics), the only such agent specifically FDA approved for ophthalmic use, into the facility fee — that are likely going to prompt changes in how they approach glaucoma surgery in the near future. (Read more about how these issues may evolve and how surgery centers are dealing with them in a future article in this series.) ■

	Jeff Maltzman, MD, FACS, specializes in cataract surgery and the medical and surgical management of glaucoma with Fishkind, Bakewell & Maltzman Eye Care and Surgery Center in Arizona
	Priya Desai, MD, MBA, a cataract and glaucoma specialist with Matossian Eye Associates, with locations in New Jersey and Pennsylvania
	Steven Vold, MD, glaucoma and cataract specialist and founder of Vold Vision in Arkansas

References

WATCH FOR FUTURE ARTICLES IN THIS SERIES