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Clinical Update: Retina Surgery
Pseudophakic Retinal Detachment Repair: Understand the Options
Although all retinal detachments have the potential to threaten vision and cause permanent loss of sight, pseudophakic detachments have some unique characteristics. Because affected eyes often are older, the vitreous tends to be more syneretic and fluid, which leads to faster accumulation of subretinal fluid and quicker progression of detachments, said Franco M. Recchia, MD.
Moreover, retinal tears are often smaller and multiple, and they can evade visualization due to cortical remnants in the capsular bag, posterior capsular opacification and optical aberrations from the IOL.
The surgeon’s utmost goal is surgical reattachment, said Dr. Recchia, associate professor of ophthalmology and chief of the retina division at the Vanderbilt Eye Institute. But addressing the patient’s expectations about uncorrected visual acuity also is important.
“I try to impress upon patients that the priority is retinal reattachment first and refractive preservation second,” he said. “We physicians understand that hierarchy, but patients often don’t, so it’s incumbent upon us to have that discussion.”
It’s also critical to carefully examine the fellow eye, which has a 10 to 40 percent incidence of tears or detachment—much higher than the 1 percent chance in the general population of postcataract eyes, said Dr. Recchia. Predisposition—genetic or otherwise—must account for this, rather than probability alone, he said. “Patient counseling and education can never be overdone. Oftentimes, these patients have symptoms for several days before they lose vision with the first detachment. So we remind them that if it ever happens in the fellow eye to call us promptly.”
From Bubbles to Buckles
Vitrectomy, scleral buckle and pneumatic retinopexy are the primary options for pseudophakic retinal repair. Laser demarcation may be an option for small detachments where the patient doesn’t notice the visual field cut. “That would be the only time I would consider it,” said Dr. Recchia, “since the laser doesn’t attach the retina, it just walls it off.”
Overall, the popularity of scleral buckling has waned as that of vitrectomy has gained. Even so, “Doctors should do what they are most comfortable with and what provides the best success in their hands,” said Dr. Recchia, adding that his procedure of choice is vitrectomy.
A self-described outlier, Paul E. Tornambe, MD, prefers pneumatic retinopexy. “As long as the implant or the capsular remnants don’t limit a view of the peripheral retina, pseudophakia is not a contraindication to pneumatic retinopexy,” said Dr. Tornambe, a retina specialist with Retina Consultants San Diego in Poway, Calif. He’s been doing this procedure for 27 years.
Vitrectomy: Gaining Preference
What accounts for the increasing use of vitrectomy in pseudophakic patients? For one thing, improved visualization of the retinal periphery means that any tears are less likely to be missed. And cataracts are no longer a concern.1
“Improvement in vitrectomy techniques and technology have also allowed us to fix a lot of pathologies that we may not have otherwise been able to do as successfully,” said Dr. Recchia. “We’ve also been able to do them with less surgical trauma, faster rehabilitation and greater patient comfort.”
For greater success with vitrectomy, consider the following tips:
Look at the lens. “See if the lens is subluxated or weak, or is a multifocal implant,” said Dr. Recchia. He noted that multifocal IOLs can be challenging for visualization because of their different optical zones.
With their concentric rings, the ReStor lenses are more difficult to work through if you need to do any macula work, said Dr. Tornambe. “If you’re doing a vitrectomy with this type of lens, you need more light and have to turn up your endoprobe intensity, which increases the chances of phototoxicity,” he added. “The image is also degraded, so the view isn’t as crisp. It’s like doing your surgery with a 20/30 or 20/40 view, rather than a 20/20 view.” And the Crystalens, with its much smaller optic, can create a jack-in-the-box effect, he said.
It also helps to know the composition of the lens in case you need to do an air-fluid exchange, said Dr. Recchia. This will help you anticipate what’s needed to avoid or mitigate fluid condensation on the surface of the IOL. For example, coating a silicone IOL with viscoelastic may help to maintain the view.
Shaving and gauging. A thorough, complete vitrectomy with 360-degree peripheral shaving can improve visual outcomes and avert the need for a scleral buckle in many, if not most, cases, except when the procedure fails due to proliferative vitreoretinopathy (PVR) or when the patient is young, said Dr. Tornambe.
With today’s firmer probes, gauge is less of a concern than in the past, when more flexible probes made it more difficult to do a good dissection of the vitreous base, said Dr. Tornambe. “But since going to [modern] cannulas with 23- and 25-gauge, we’re getting fewer postop detachments and tears.”
Beware bubble trouble. Patients cannot fly postoperatively until the gas bubble is almost gone. They also should wear a medical alert wristband. If general anesthesia is needed, nitrous cannot be used because it can cause expansion of the gas bubble and increase IOP.
With scleral buckles, one problem is visualization—identifying all pathology if there is a small pupil or media opacities such as vitreous blood, capsular clouding, lens remnants or asteroid hyalosis, said Dr. Tornambe. In addition, by putting a foreign body around the eye and opening the conjunctiva 360 degrees, there is a greater chance of inflammation, scarring, dry eye and double vision.
Other concerns include the challenge of doing any glaucoma or strabismus surgery in the future, said Dr. Recchia, as well as the risk of inducing refractive changes. He doesn’t recommend scleral buckling for patients who have glaucoma, especially if they have a filtering bleb or may need additional glaucoma surgery.
Although fewer physicians are now using a primary buckle for pseudophakic retinal detachments, said Dr. Recchia, the buckle’s advantage is that you don’t enter the eye. “Its success depends on seeing well enough to find, treat—usually with cryotherapy—and support all breaks with an appropriately placed buckling element,” he said. An encircling 41- or 42-style band is used to support the vitreous base, and care should be given to placing it at the posterior border of the vitreous base to support all open retinal breaks and areas of weakness that may lead to retinal breaks later on.
Best use of buckles. Dr. Recchia said the buckle is most often coupled with a vitrectomy to fully address the causative tears. He recommends it for patients who have one or more of the following:
Although Dr. Tornambe usually uses rescue vitrectomies after a failed pneumatic retinopexy, he said a scleral buckle in addition to the vitrectomy is in order if new, large tears develop or if multiple tears occur—problems that point to an abnormal vitreous.
With lower single-procedure success rates, pneumatic retinopexy has struggled to gain traction over the years. For example, a recent study from Duke University found single-procedure anatomic success rates of 60 percent, vs. 79 percent for pars plana vitrectomy and 81 percent for scleral buckle.2 But success rates have varied greatly, depending largely upon inclusion criteria.3
Cautions to consider. The lower success rates may be because the pupil does not dilate as well, thanks to patient age, or because of previous surgeries, said Dr. Recchia. Visualization can also be a challenge due to capsule or IOL interference. “Since causative breaks in pseudophakes tend to be small, peripheral and multiple, it’s likely you’ll miss them if your visualization is not optimal.” And results are not good if breaks are in the inferior one-third of the fundus or are separated by more than one clock hour.
Also, if a lens implant is unstable, the gas bubble can displace it, something that is more difficult to correct with an office procedure than in the hospital during a vitrectomy. And body position is crucial for a couple of days for the gas bubble to achieve appropriate pressure against the retinal break(s). After the procedure, patients must take the same precautions with travel as vitrectomy patients do.
Patient selection. Although pneumatic retinopexy is a minimalist operation that’s deceptively simple to do, said Dr. Tornambe, it takes intuition and experience to pick the right patient and recognize all the pathology.
“If patients don’t ‘put the bubble on the trouble,’ the operation won’t work,” he said. “They have to have the mental and physical capacity to position themselves properly.” The easiest breaks for positioning are in the vertical and horizontal meridians. More difficult are those in oblique meridians where positioning requires tilting the head, he said. To help with the process, Dr. Tornambe invented a circular pneumo level akin to those used on construction sites. With clock hours painted on its surface, it’s stuck onto a patient’s patch, providing a guide to the patient or caregiver for meridian positioning.
A patient who is afraid of or not a good candidate for surgery and anesthesia may be especially well suited for pneumatic retinopexy.
Ultimate outcomes. Although anatomic success rates are lower than those of incisional surgery in the OR, in experienced hands, the results of pneumatic retinopexy are comparable, said Dr. Recchia.
This goes for visual success as well, Dr. Tornambe said. “If you have a patient—pseudophakic or not—with a retinal detachment with the macula off for two weeks or less, and you do a pneumatic, at the end of two years there’s almost a 90 percent chance that patient will have 20/50 or better vision. Those are better numbers than for scleral buckling and better numbers than I’ve seen for vitrectomy,” he argued.
Some controversy still persists, however, about ultimate visual outcomes. For example, a restrospective study reviewing primary pneumatic retinopexy procedures within a single retinal group suggested that avoiding rescue procedures provided better visual acuity.4
However, Dr. Tornambe said that a failed pneumatic procedure doesn’t disadvantage the eye to either ultimate anatomic or visual outcomes. The key, he said, is doing the rescue operation in a timely way, within three to five days. “If you delay treatment, that’s where you get into problems such as PVR, inflammation and puckers, and that’s where pneumatic retinopexy has gotten a bad rap.”
In addition to good visual outcomes, lowered morbidity and less stress for the patient, the procedure is about one-seventh the cost of taking the patient to the hospital, he said.