Pneumatic Retinopexy: Failure, 360º Laser, Pseudophakes

An interview with Paul E. Tornambe, MD

DAVID C. REED, MD • MITCHELL S. FINEMAN, MD

Pneumatic retinopexy (PR) has been well established as a safe and effective means for repairing retinal detachment in selected patients. However, certain aspects of the procedure remain unsettled in the literature, and there are differing opinions and practices regarding them among retinal surgeons.

We had the opportunity to interview Paul Tornambe, MD, one of the originators and early advocates of the procedure, on the following topics: 1) Is it true that a failed attempt at PR does not harm the eye? What is the best way to manage PR failures? 2) Should 360º prophylactic laser be performed in all patients, as you have previously advocated? 3) How do you weigh the pros and cons of pars plana vitrectomy vs PR in pseudophakic patients who are otherwise excellent PR candidates?

PNEUMATIC FAILURES

Question: The data, notably from the prospective, randomized Pneumatic Retinopexy Clinical Trial, suggest that failed PR does not harm the eye as long as the PR was performed with good technique, and the rescue procedure is promptly performed.^1-3

Suppose a patient with a macula-on detachment is an ideal candidate for PR, but the PR fails, and the patient’s macula becomes detached before his or her second surgery. Was this patient harmed by the PR attempt? Could it be true that failed PR attempts do not harm eyes in the aggregate but may harm an individual eye?

Paul Tornambe, MD: One of the main reasons surgeons get into trouble is they wait too long to declare the pneumatic failed and to fix it when it does fail. Usually, the primary break is closed on postop day 1 — certainly by postop day 2. There may be residual inferior fluid, and that’s OK, for it will resolve with time.

Dr. Tornambe

But once the break is closed, the macula quickly attaches. If the macula is not attached by day 2, there is a missed or open break. By day 2, if the pneumatic is not working, and especially if you put in cryopexy, it’s time to go to the OR.

I tell patients that I will put in a bubble and see them tomorrow, often NPO. If the procedure isn’t working, then we go to the OR in approximately the same time frame as we would have had we not tried the PR first. So the scenario you describe is possible but rare.

Also, in the Pneumatic Retinopexy Clinical Trial, 89% of eyes with preoperative macular detachment of less than 14 days treated with PR attained 20/50 or better vision at two years.² So although I don’t want the macula to detach, I don’t think a brief period of macular detachment is fatal in the rare cases that it does occur in the time between a failed PR attempt and a rescue procedure. Overall, the study confirmed that a pneumatic attempt does not harm the eye’s potential to ultimately attain good vision.

In fact, the two-year data from the Pneumatic Retinopexy Clinical Trial showed that the final best-corrected visual acuity results ranked, from best to worst, were: 1) successful PR; 2) failed PR rescued with a second PR; 3) successful scleral buckle; and 4) failed scleral buckle rescued by another procedure. Even this is only part of the story. An eye with a big scleral buckle may be able to see 20/20, but strabismus and anisometropia aren’t taken into account.

Because a failed pneumatic attempt does not harm the eye, single operation success (SOS) is not the most important metric. As surgeons, this is a hard fact to come to grips with. We all want our procedures to have high success rates, and doing a procedure with a 70% success rate just doesn’t make sense to many.

But consider this way of looking at it: seven out of 10 pneumatic candidates avoided the OR, avoided anesthesia, avoided exposure to many surgical complications, had less morbidity, had faster visual recovery, and had better final visual acuity. Three out of 10 were unharmed by the PR attempt and had the surgery they would have had, anyway. If the PR fails, get them to the OR promptly, and you haven’t done any harm.

Besides, the 70% published rate for PR is artificially low because some of the failures can be fixed by adding laser or another spot of cryo and changing position, for example. We counted these “enhancements” as reoperations in our study. And the 90% success rate for incisional procedures that we often quote is likely an overestimate if you really look into the literature.

A related scenario that comes up more commonly is a macula-threatening detachment, where the gas bubble pushes the fluid into the macula. To avoid this displacement of fluid, in these situations I utilize the steamroller technique (see Figure, page 44) to reduce the amount of subretinal fluid, minimizing the chance of displacing subretinal fluid beneath the fovea.

Figure. Rhegmatogenous retinal detachment: A) before treatment; and B) 10 minutes after steamroller technique.
PHOTO COURTESY OF PAUL TORNAMBE, MD

Q: In cases of pneumatic failures that must be fixed with incisional surgery, what are your thoughts on choice of procedure?

PT: Because I’ve liberated RPE cells with cryotherapy, I lean toward doing a PPV. For multiple breaks, inferior breaks, extensive lattice, or PVR, I might do a scleral buckle/PPV. In most cases, adding a scleral buckle to the PPV is excessive. It might make you feel a little better, but I’m not sure it’s necessary.

I would consider doing a straight buckle, however, in a young phakic patient on whom I planned a staged procedure with laser and hadn’t done cryo. I would also lean toward a straight buckle in a patient without a PVD.

360º LASER

Q: In your 1997 series of 302 consecutive patients treated with PR, you reported that, among those with classic indications for PR, SOS significantly improved from 63% with focal pexy only to 91% with 360º laser.⁴ There have been no publications since then to confirm or refute this finding. Do you still perform 360º laser in all cases?

PT: Today, I hardly ever do 360º laser retinopexy for PR. I try to follow Machemer’s advice: The retina wants to attach, and if you don’t do too much to it, it probably will. The less you do to the eye, the better.

My current SOS is about 75%, so to increase my SOS by 10%, I would need to unnecessarily perform 360º laser on that 75% who would have had success without it. That seems excessive to me. For me, there has to be a good reason to do 360º laser — such as multiple breaks or extensive lattice.

These eyes have an abnormal vitreoretinal interface, so I think the laser can be helpful in preventing new breaks from becoming detachments. Even though the laser is probably not harmful, I do wonder if ablating all that RPE reduces the eye’s capacity to resorb subretinal fluid.

The ability of the RPE to pump subretinal fluid can be astonishing, and I want to preserve that. I note that many surgeons advise 360º laser when repairing detachments with vitrectomy. I think this is also excessive.

The 360º laser doesn’t prevent new breaks from developing, but “pretreats” them. It also treats “missed breaks” in flat retina. Round holes in flat retina are present in 5% of the population. These may be very easy to overlook.

If you’re a great observer, you might pick these up and focally treat them. If you miss them and displace subretinal fluid into them, they will keep the retina detached and the surgeon will call it a new break.

If subretinal fluid is not displaced into the hole, the tractionless hole will not detach the retina, even if not treated. So the better your pre-operative exam, the less you may need 360º laser.

Q: In cases in which you do 360º laser for PR, can you describe your technique?

PT: I identify the posterior vitreous base by locating the most posterior break, and I laser from there to the ora. I stay at least one clock hour away from detached retina in case my bubble displaces fluid into the area of fresh laser and causes small breaks.

By reducing the amount of subretinal fluid, the steamroller technique can be useful to prevent this problem as well. Also, scleral depression may fool you into lasering slightly elevated retina, which can cause holes. I space the burns one or two spots apart, and I make them a light gray intensity — not chalk white, because this can cause necrosis and breaks.

Q: What happens when a patient who has received PR with 360º laser has a failure? Does the ensuing retinal detachment have many small breaks where the laser marks were?

PT: I haven’t seen any cases where the retinal detachment causes a million small holes in this situation.

PNEUMATIC RETINOPEXY IN PSEUDOPHAKES

Q: The pros and cons of PR vs scleral buckle have been well established, but the pros and cons of PR vs modern PPV have not been as well studied. No prospective studies comparing PR and PPV have been performed.

Suppose you have a pseudophakic, emmetropic, 60-year-old, otherwise healthy patient with a macula-on superior detachment between 10:30 and 1:30 with a single small horseshoe tear at 12 o’clock and a PVD (ie, an ideal pseudophakic PR candidate).

Would you perform a PR or a PPV? In pseudophakes, the morbidity of PPV and PR is more similar than the morbidity of scleral buckle and PR.

PT: I want to make this really a strong point: Pseudophakia doesn’t make a difference. It doesn’t even come into my algorithm. It doesn’t affect me at all, assuming visualization is good.

In most pseudophakes, the visualization is great. The eye in your scenario would do well with a PR. And again, look at the vitrectomy literature. The success rate is not 90% to 95%. It’s more like 80%.

So the SOS between pneumatic and PPV are not all that different. PPV is basically “commando pneumatic” anyway but probably has a higher risk of serious complications than PR, such as choroidal detachment, hypotony, and endophthalmitis.

In this situation, I would tell the patient, “I’m going to put in this bubble. If it doesn’t work by tomorrow, I’m going to take you to surgery.” Give it a try. You’re not going to hurt anything.

In situations where there are relative contraindications to PR (eg, multiple breaks separated by two clock hours), I will just put in a gas bubble without cryo and see how it goes. I’m often pleasantly surprised and if it doesn’t work no harm is done.

In my own practice, about 70% of nontraumatic primary retinal detachments are pneumatic candidates, and my SOS is about 75%. As a specialty, we are underutilizing PR.

And we haven’t even discussed the cost advantages of PR over incisional surgeries. With PR, the costs of anesthesia and the facility fee are completely taken out of the picture. As doctors will increasingly be judged not only by outcomes but also by outcomes per dollar spent, I think PR will become even more popular.

One creative reimbursement arrangement I once participated in was that I didn’t get paid for failed pneumatics, but I got paid a bonus by the hospital system for successful cases, as these kept costs down for the system. I came out way ahead, because about seven or eight out of 10 pneumatics were successful.

I believe such a reimbursement arrangement creates incentives that are more aligned with what is in patients’ best interests than the current one, where incisional surgeries reimburse at a higher rate than PR. RP

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