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Feature
Posterior Capsular Rupture During Cataract Surgery
By Laura J. Rongé, Contributing Writer
 
 

Every surgeon can expect one, but anticipation and preparation can make
a rupture in the posterior capsule a manageable crisis.

Recognize it. Stop. Stabilize it. These are three keys to catching a small posterior capsular rupture before it becomes a larger rupture, and a much more complicated case.

“All cataract surgeons will get a rupture, and hope is not a good strategy,” said Randall J. Olson, MD. Following are some approaches offered by Dr. Olson and other experts for dealing with breaks in the posterior capsule during cataract surgery.

Recognize It
First, prevention is always better than treatment. “The best of practices have a rupture rate in the range of two to four per thousand cases. It can be that low,” Dr. Olson said. “If I’ve had four in the last 200 cases, or 2 percent, I have to ask, ‘What can I do to get it lower?’”

Use techniques that keep you away from the capsule, Dr. Olson suggested, and keep a log of your capsular ruptures. “Videotape them, and review the tapes. By recognizing those steps that led to a rupture, you can change your technique to avoid it,” he said.

In this way, Dr. Olson discovered that his most common rupture occurred while polishing the posterior capsule with an irrigation-aspiration tip in which he finds a barb. “Something abnormal was occurring during autoclaving,” he explained. “That has changed my whole thought process.”

You can also lower your rupture rate by using the newer-generation phaco systems (such as the AMO Sovereign, Alcon Infiniti and Bausch & Lomb Millennium), which provide improved fluidic surge protection, said R. Bruce Wallace III, MD.

Stop and Stabilize
When you suspect a tear in the posterior capsule, immediately stop all aspiration and ultrasound. Keep the infusion on and the phaco or I&A tip still, advised Jack A. Singer, MD. Do not use the irrigating tip to move things out of the way. “Even if you are just irrigating, a small amount of flow may be coming up the tip. I take my second instrument to clear away and take a look at that area,” Dr. Olson said.

Once you confirm a rupture, keep irrigating (but not aspirating). “Go through your side-port incision, and start right down on the rupture putting dispersive viscoelastic to tamponade and reinforce that area, to push everything out of the way. Fill the anterior chamber and give a bolus of viscoelastic as you come out of the eye. This maintains a deep anterior chamber, and no positive net flow from vitreous moving forward,” Dr. Olson said.

In the setting of a ruptured posterior capsule, it is advisable to use a dispersive ophthalmic viscoelastic, such as Viscoat (Alcon) or Vitrax (AMO), said David F. Chang, MD. “These agents tend to resist aspiration and are less easily burped out of the eye,” he explained. “When left behind in the posterior segment, these agents should cause fewer problems with postoperative IOP than a cohesive viscoelastic would.”

Choose Your Surgical Strategy
When you have a stable situation, with the chamber full of dispersive viscoelastic, Dr. Olson said, take a minute to look and decide your next step. Your surgical strategy depends on the severity of the rupture.

Posterior capsulorhexis. If no vitreous was aspirated, and the rupture is very small and clearly visible with no large linear extensions, try to convert it into a posterior capsulorhexis. “A posterior capsulorhexis is a little trickier than an anterior capsulorhexis, but the principle is the same,” Dr. Olson said. “The only difference is the size. The best ones are 2 to 3 millimeters. Obviously, it can’t be smaller than the size of the tear.”

Try to keep the posterior capsulorhexis as small as possible because it will usually end up larger than intended, Dr. Singer added. He finds the Inamura Capsulorhexis Forceps useful for this maneuver because of its downward curve and crossed-action.

In many cases, a posterior capsulorhexis makes it possible to implant the IOLs in the bag, especially single-piece acrylic lenses, which are more easily manipulated between the anterior capsule and remaining posterior capsule, explained Richard J. Mackool, MD.

Retrieving the nucleus. If the vitreous has not prolapsed through the posterior capsule defect, fill the retrocapsular space behind the defect. “Many times it may take an entire vial of viscoelastic to fill the retrocapsular space between the anterior hyaloid face and posterior capsule remnant. The dispersive viscoelastic serves as an effective barrier to vitreous prolapse while preventing posterior dislocation of lens material,” Dr. Singer said. He then viscodissects or manually moves the remaining lens material up out of the remaining capsule and into the anterior chamber, where it can be safely emulsified and aspirated.  

Dr. Wallace pointed out that it is sometimes helpful to insert a Phacoglide, which is a modified Sheets glide, underneath the nuclear material so that you can do phaco without coming into contact with vitreous strands.

If you have a very large rupture and think you may lose the nucleus, consider extending the phaco incision and getting the nucleus out before you do a vitrectomy, Dr. Olson suggested.

Posterior assisted levitation. In cases where the nucleus is partially descended, Dr. Chang advises against chasing it with the phaco tip. Instead, he recommends using a Viscoat posterior assisted levitation method.1 He uses a pars plana sclerotomy to inject supplemental supporting viscoelastic behind the nucleus, and then uses the cannula tip to elevate the nuclear fragments forward through the pupil, under direct microscopic visualization. “Once the nucleus is in the anterior chamber, you can manually extract it through a larger limbal incision,” he said.

Proceed cautiously at a low flow rate, keeping well away from the rupture, said Dr. Olson. “When doing irrigation and aspiration, I start out as far as I can in the peripheral capsule, and I pull out the cortex,” he said. Anytime he thinks that he is losing the dispersive viscoelastic tamponade, he injects more viscoelastic.

Only surgeons who have significant experience should attempt to retrieve nuclear segments that have been displaced into the vitreous cavity, according to Dr. Mackool. An alternative is to do a thorough anterior vitrectomy, implant the appropriate IOL, and then refer the patient to a vitreoretinal surgeon for completion of lens fragment removal, he said.

Pars plana vitrectomy. If you have grabbed vitreous, quit aspirating. Don’t move your tip. “Go back with your viscoelastic, and start irrigating near the break. Try to physically sweep the vitreous out of your tip, while pushing it down, so that you are not stretching it any further,” Dr. Olson said. To remove prolapsed vitreous, he noted, a pars plana vitrectomy is the best option.

Dr. Chang agreed: “The pars plana approach provides a better angle for positioning instrument tips behind the nucleus.” He uses a disposable #19 microvitreoretinal blade to make the pars plana sclerotomy 3.5 mm behind the limbus, in one of the oblique quadrants.

With the pars plana approach, you are pulling the vitreous back, rather than forward toward your main incision. “All of your net forces are pushing posteriorly, so you are much less likely to pull a vitreous strand up to one of your incisions,” Dr. Olson said.

According to Dr. Olson, leaders in the field have given up doing a coaxial vitrectomy through the main incision. “You will always cut out more, and if you are stretching vitreous strands all the way to your main incision, the chance of retinal detachment or cystoid macular edema increases dramatically,” he said. Before starting the pars plana anterior vitrectomy, make sure any remaining nucleus is completely stabilized and supported.

“If you have small fragments, or intend to resume phaco, it is important to avoid aspirating prolapsed vitreous. To avoid posterior descent of lens material as you excise the supporting anterior vitreous with a vitrectomy cutter, I use a strategy I call the ‘Viscoat Trap,’”2,3 Dr. Chang said. “After elevating the residual lens fragments toward the cornea, I fill the anterior chamber with a dispersive viscoelastic, thereby trapping residual nuclear and epinuclear fragments.”

He introduces the vitrectomy cutter through the pars plana sclerotomy with a separated infusion through a self-retaining limbal cannula. “In this way, I can keep the vitrectomy tip located in the posterior chamber as I sever any forward-extending transpupillary bands of vitreous,” Dr. Chang said. “This prevents evacuation of the partitioning Viscoat layer, which is now supporting the mobile lens material in the absence of the vitreous.”

Always have a small irrigating hand piece available, Dr. Olson suggested. “They are inexpensive, and they come in 21- and 23-gauge sizes. If you are making a 20-gauge incision, you need a 21-gauge irrigator. For most of the really small stab incisions, a 23-gauge is a better irrigator.” Dr. Olson goes through his stab incision and, using a very low flow rate, he irrigates on the top from front to back, but not into the opening of the rupture. “You do not want to irrigate the vitreous,” he said.

This is one reason that he uses the side-port for irrigation. “If you irrigate through the main incision, you end up hydrating the vitreous, blowing fluid right where you are cutting. You have to do a much bigger vitrectomy, generally, and it is hard to avoid having vitreous strands coming back up to the wound,” he said. It is a good idea to stromally hydrate the abandoned main incision, he added.

Cut the prolapsed vitreous. Use a vitrectomy tip cutting rate of at least 800 cuts per minute, Dr. Mackool advised. “A vacuum pressure of approximately 100 to 150 mmHg and aspiration flow rate of 15 to 25 cc/minute are appropriate for efficient removal of vitreous. The cutter port would normally be set to the maximally open position. In most cases, the infusion bottle must be elevated to at least 90 to 100 centimeters,” he said.

Dr. Wallace adjusts the vitrector fluidics and cutting speeds according to the type of expulsate being removed.

Dr. Mackool noted that it is important to remove all prolapsed vitreous from the anterior segment, and well behind the plane of the posterior capsule.

Cut the vitreous from up above. “Keep cutting as you come back out of the eye,” Dr. Olson said. “As you get right to the pars plana opening, do just a little cutting to clean out any vitreous that may be there.” Finally, put a single stitch to close the pars plana sclerotomy. Dr. Olson uses a 10-0 nylon stitch. Dr. Chang uses an 8-0 Vicryl suture. Cover the stitch with the conjunctival flap.

Inserting the IOL
If you can do a small posterior capsulorhexis, put the IOL in the capsular bag. If it is a larger tear, put the lens in the ciliary sulcus and do an optic capture, Dr. Olson advised. Start with a stable situation with plenty of dispersive viscoelastic maintaining the anterior chamber.

Carefully insert the IOL into the sulcus. To make sure that the IOL goes under the iris and into the sulcus, use a two-handed technique. “I use one hand to rotate the optic, the other to compress the haptic. Once I have it in position, I use a Sinskey hook to push the optic inside the anterior capsulorhexis, and then slide across and push the other side under,” Dr. Olson explained.

The anterior capsulorhexis must be between 4.5 and 5.5 mm, a little smaller than the optic, he said. If the anterior capsulorhexis is too big, the IOL will not stay in place; if it is too small, it is hard to fit and position the IOL. If the capsulorhexis is not well-centered, the optic will not be centered.

If the diameter of the capsulorhexis is approximately 4.5 mm or smaller, you can capture a multipiece IOL with an optic of 6 mm or larger, Dr. Mackool added. If the capsulorhexis is slightly larger (i.e., up to 5.5 mm), you can use an IOL such as the MA50 Alcon acrylic multipiece lens with a 6.5 mm optic, he said.

Rhexis fixation of the IOL helps prevent late IOL decentration and pupillary block by holding the optic centered and back from the iris, Dr. Singer explained. Reverse optic capture of a bag-fixated IOL through the anterior capsulorhexis can help to stabilize the IOL if a noncontinuous or large posterior capsule defect occurs after implanting the lens, Dr. Singer added.

Adjust the IOL power. “There are more complex formulas out there, but this is a general rule that has worked well for me: If the posterior chamber lens is fully in the ciliary sulcus, I drop the power by 1 diopter,” Dr. Olson explained. “When it is captured in the anterior capsulorhexis, I lower the power by a half diopter. Even with optic capture, however, if IOL power is more than 23 or 24 diopters, I lower the power one full diopter.”

Closing the Case
Remove the viscoelastic.
Dispersive viscoelastic is moderately forgiving, Dr. Olson noted, and he does not worry about viscoelastic that is sitting behind the capsule. “I remove the viscoelastic starting in the front and moving back to the lens. I push the lens back slightly to make sure I have a tamponade, and take out what is there. I don’t get aggressive about it. I stay right near the center of the lens, aspirate, push a little bit, and I can get most of the viscoelastic out,” he said.

Check for residual vitreous strands. An intraocular miotic agent helps here. Even the best surgeons may have a small single vitreous strand coming up to the limbal side-port incision, Dr. Olson said. “If you see it during surgery, go ahead and cut that out. If you don’t see it until the end of the case, and you have already closed your posterior incision, try to sweep it free. If you see it the next day, and the patient is doing well; the vitreous is just up to the stab incision and not coming out through the wound; then watch them carefully. I give it a little time, and then I use the YAG laser to cut it free,” he said.

To control inflammation, Dr. Olson prescribes nonsteroidal anti-inflammatory medications four times a day after surgery. He also sutures the clear corneal incision in each one of these cases and removes the suture in a week. “In a study now in press, we found that a broken capsule or zonules is associated with a fifteen- to seventeenfold increased risk of endophthalmitis with clear corneal incisions,” Dr. Olson explained.

But the techniques and precautions outlined above “can make these cases routine,” he said.

______________________________________
1 Chang, D. F. and R. B. Packard. J Cataract Refract Surg 2003;29: 1860–1865.
2 Chang, D. F. Tech Ophthalmol 2003;1(4):201–206.     
3 Chang, D. F. “Strategies for Managing Posterior Capsular Rupture in Phaco Chop,” in Mastering Techniques, Optimizing Technology, and Avoiding Complications (Thorofare, N.J.: Slack Inc., 2004).

Staining the Vitreous
Filtered Kenalog “staining” of the vitreous¹ is a useful technique, Dr. Chang said, but he relies on it mainly to visualize vitreous when an IOL is already present in the eye.

“These are the situations where prolapsing knuckles of vitreous get caught, and yet where it is hard to do a liberal vitrectomy. Therefore, the surgeon may not realize how much vitreous has prolapsed or is entrapped until the postoperative slit-lamp examination is performed,” he said.

Dr. Olson advised caution because Kenalog is potentially inflammagenic and can cause steroid glaucoma. “There is a nonsteroidal analog to Kenalog, but it is not FDA-approved yet,” he noted.

________________________________
1 Burk, S. E. et al. J Cataract Refract Surg 2003;29:645–651.

 

Be Prepared

While a surgeon’s best efforts can keep the rupture rate very low, Dr. Wallace said, “we all encounter an occasional posterior capsular rupture.”

So what do you do? Expect a rupture at all times. “A small rupture becomes a large one in a matter of seconds,” Dr. Olson explained. “If you have a high level of suspicion, you should be able to catch a small rupture without grasping vitreous about 95 percent of the time.”

Recognize these danger signals:

  • a failed capsulorhexis
  • any unusual tilt of the nucleus during phaco
  • sudden deepening of the anterior chamber
  • loss of nuclear followability
  • visualization of capsular puncture at the end of phacoemulsification
  • any unusual capsular striae at the I&A tip during cortical removal
  • an occult capsular tear that went unnoticed until cortical removal

Vitrectomy kit
It’s also important to have a vitrectomy kit on hand. Dr.
Wallace recommends the Nichamin System, which includes the following:

  • Dispersive viscoelastic
  • Phacoglide (Visitec)
  • 15-degree or microvitreoretinal blade
  • Vitrectomy hand piece
  • Separate irrigation hand piece: Storz E4421 or Duckworth & Kent 8-652-1


MEET THE EXPERTS
Jack A. Singer, MD  President, Singer Eye Center, Randolph, Vt. Financial interests: None. 

R. Bruce Wallace III, MD, FACS  Clinical professor of ophthalmology at Louisiana State University, New Orleans, and assistant clinical professor of ophthalmology at Tulane University. Financial interests: Is a paid consultant for AMO but has no direct financial interest in any of the products mentioned.

David F. Chang, MD  Clinical professor at the University of California, San Francisco, and in private practice in Los Altos, Calif. Financial interests: Consultant for AMO, consultant and U.S. medical monitor for Visiogen, and has received educational travel support from Alcon; no financial interest in any instruments or devices mentioned.

Randall J. Olson, MD  Professor and chairman of ophthalmology and visual sciences, and director, John A. Moran Eye Center, University of Utah, Salt Lake City. Financial interests: Consultant for AMO and head of the medical advisory board for Calhoun Vision.

Richard J. Mackool, MD  Director of The Mackool Eye Institute, and senior attending surgeon, New York Eye & Ear Infirmary. Financial interests: Consultant to Alcon.