That Sinking Feeling: Intraoperative Cataract Complications
Top Surgeons Offer Help for Those Critical Moments.
BY JERRY HELZNER, SENIOR EDITOR
What does it take to ruin a cataract surgeon's day?
Let me count the ways. A patient's sudden sneeze or cough. Dropped nuclei. Instability in the anterior chamber during the procedure caused by weak or damaged zonules. The patient who neglects to tell the surgeon that he has taken tamsulosin (Flomax) and has iris billowing and prolapse. Inadvertent phaco tip contact with the capsule. A rock-hard nucleus. Suprachoroidal or retrobulbar hemorrhage. And those are only a few.
Anyone considering ophthalmology as a career choice might want to reconsider after reading the previous paragraph. But since it's impossible to perform surgery with your fingers crossed, Ophthalmology Management asked several top cataract surgeons to recommend immediate steps for dealing with intraoperative complications.
The Range of Complications
The most commonly mentioned unanticipated cataract complications include intraoperative floppy iris syndrome (IFIS), anterior chamber instability from weak zonules or zonular dialysis, dropped lens fragments, rock-hard nucleus, capsule rupture and hemorrhage. However, the surgeons that we contacted also noted some other serious — but less common — complications, and Robert Rivera, MD, who practices in Phoenix, is concerned about a new complication that he has recently encountered but that has not yet been widely studied.
Let's begin with the more common intraoperative complications that test the skills of even the most talented cataract surgeons.
IFIS
Although IFIS (Figure 1) is usually anticipated from the patient's medication history, surgeons are sometimes surprised at unexpected degrees of miosis and iris prolapse where the pupil had dilated well preoperatively.
COURTESY OF DAVID CHANG, MD
Figure 1. IFIS, which is characterized by iris billowing and prolapse, has emerged in recent years as one of the most prevalent intraoperative complications.
Intracameral epinephrine (diluted with plain BSS to 1:4000) will “increase iris rigidity by improving the dilator muscle tone, and may occasionally further expand the constricting pupil,” advises widely renowned cataract surgeon David Chang, MD, of Los Altos, Calif.
“Although the Malyugin Ring or iris retractors can still be inserted midway through the phaco step, they are more difficult to insert once the capsulorhexis has been completed and without a good red reflex,” says Dr. Chang.
“The most common bit of trickery I encounter in the operating room is IFIS,” says Michael Korenfeld, MD, of Washington, Mo. “I find it to be a very interesting clinical condition.”
Dr. Korenfeld believes IFIS is still poorly understood. He has seen both men and women with the condition who are not on any of the drugs that are thought to cause this problem. He sees patients who were treated with the offending drugs who stopped them over a year ago and still experience IFIS, which he says makes no pharmacological or clinical sense.
“I see patients who may be at risk for IFIS start out with a beautifully dilated pupil, with what seems like normal iris tone, who then degenerate into significant floppiness as the case progresses, usually during the actual phacoemulsification. That doesn't make a whole lot of sense to me either,” he says.
Praise for the Malyugin Ring
When an IFIS case does require a mechanical device, Dr. Korenfeld and several other surgeons interviewed for this article are advocates of the Malyugin Ring. (Figure 2)
COURTESY OF BORIS MALYUGIN, MD
Figure 2. The Malyugin Ring has moved to the forefront of effective methods for dealing with IFIS and small pupils.
“I am a very strong proponent of the Malyugin Ring,” asserts Dr. Korenfeld. “I want to look Boris in the eye some day and thank him for his wickedly simple and reliable invention. It has never failed me.”
Dr. Korenfeld has so far used only the 6 mm device, though he believes the recently introduced 7 mm device may be a better choice because “you don't have to dance at the pupillary border during the capsulorhexis, and the 7 mm device would be better to insert in the at-risk patients at the beginning of the case, when the pupil may well start out at 6 mm, before its ultimate degeneration into floppiness.”
Though insertion of the Malyugin ring after completion of capsulorhexis is not Dr. Korenfeld's preference, he says that such insertion “is typically fine if the scrolled segments capture the capsulorhexis edge, as long as you don't have a pre-existing discontinuity in the anterior capsulorhexis.”
Dr. Korenfeld advises that with a torn capsulorhexis, the surgeon should make sure to only engage the pupillary border.
“I also suspect that if you inadvertently capture the capsulorhexis edge with a scroll, it would be best to only do this with one or two scrolls, since the expansile forces on the anterior capsulorhexis could overcome its structural integrity and create a big radial tear,” he cautions. “I suspect this would be even more of an issue with the 7 mm device, which would have a greater expansile force than the 6 mm device.”
Dr. Rivera is another fan of the Malyugin Ring, which he believes has revolutionized small-pupil surgery.
“We have a substantial population of patients using Flomax and other alpha blockers, and with our high-volume practice, we might go through six to 12 rings a week,” he notes. “The technique is a time-saver as compared to other techniques, i.e., iris hooks, and the pupil appearance postoperatively is quite remarkable. It is such an ingenious concept that the most common thought that goes through a surgeon's mind on seeing it work is, ‘Why didn't I think of that?’ I believe it is one of the greatest advances in treating and preventing complications in cataract surgery, and overall ranks right up there with viscoelastics, capsular dye and capsular tension rings. All that from a piece of fishing line!”
And this comment from Steven Dewey, MD, of Colorado Springs, Colo.
“You cannot be sure that your patients will tell you that they have been on Flomax,” he asserts. “I had a physician as a cataract surgery patient recently and he didn't tell me that he had taken Flomax seasonally to counteract the effects of allergy medication on his prostate. He had severe IRIS billowing and prolapse.”
Dr. Dewey says the ease of insertion and removal of the Malyugin Ring makes it highly useful in severe IFIS cases such as with the patient he describes.
Zonular Issues
Dr. Chang notes that although there are several known risk factors for weak zonules (Pseudoexfoliation, prior vitrectomy or trabeculectomy, trauma, Marfan's or retinopathy of prematurity), the presence and extent of zonular laxity is typically not known until the capsulorhexis is performed.
Dr. Chang says taking this step essentially anchors the capsular bag to the eye wall and facilitates nuclear rotation and removal without impeding cortical removal. He notes that cortical cleanup may be safer with bimanual I&A instrumentation, which minimizes the need to turn the aspirating port toward the equator or posterior capsule, particularly in the sub-incisional area.
“Reducing aspiration flow and vacuum alone will not prevent trampolining of a lax posterior capsule toward the phaco or I&A tip,” he adds. “However, a dispersive OVD, such as Viscoat, is able to fill and distend the capsular bag, resist aspiration, and restrain the lax posterior capsule from being aspirated along with the final loose nuclear fragments or the cortex.”
These measures allow the surgeon to delay capsular tension ring (CTR) insertion until after the cortex is removed.
“Zonular dialysis is really a pain,” says Dr. Korenfeld. “Unlike a broken posterior capsule, where you can place a sulcus-fixated lens if the anterior capsulorhexis is still intact and you've cleaned up the vitreous, the zonular dialysis is different.”
With a zonular dialysis, removing any remainder of the lens becomes quite tricky. Dr. Korenfeld strongly recommends that the surgeon stop using the automated I-A device and convert to a manual Simcoe I-A, which is a more controlled way of removing lens material.
“You can feel what you are doing proprioceptively, and if you need a little controlled reflux to release an engaged lens capsule, it is very easy.” Dr. Korenfeld notes.
He says the automated I&A provides only visual feedback, which is typically tolerable for normal cases, but intolerable for abnormal capsules.
“If you only have a couple clock hours of zonular dehiscence, you could potentially put in a capsular tension ring, and then an in-the-bag IOL. If the number of clock hours of involvement is bigger, then you will need to put in an AC IOL — which I reluctantly prefer, with an iridotomy — or sew in a sulcus lens, which is difficult and time consuming at best, and potentially more traumatic to the eye than it's worth.”
Using a CTR and an in-the-bag IOL could introduce astigmatism if the IOL plane tilts. This astigmatism that may be difficult to neutralize with glasses or contact lenses, cautions Dr. Korenfeld.
“If the situation is disabling for the patient, you will need to expiant the IOL-capsular complex and do a vitrectomy, and then put in an AC IOL. Since modern AC IOLs are of good design, I tend toward them when the zonular dialysis seems too big to chance this IOL tilting phenomenon.”
Dropped Nuclei
Dealing with dropped lens fragments is one of the more dreaded intraoperative complications because of the magnitude of the decision to be made in this situation. The cataract surgeon can either attempt to resolve the problem during surgery or refer the case to a retina specialist for a later pars plana vitrectomy. Anxiety over facing a second procedure can be debilitating to the patient. It often takes time to schedule a vitreoretinal surgeon to retrieve the fragments, which is a major concern to the patient and the cataract surgeon.
Steven Silverstein, MD, of Kansas City, Mo., advises the following steps if the nucleus or fragment is still anteriorly positioned on top of the vitreous face:
► Having a second instrument to stabilize the fragment from below.
► Lowering the flow rate and bottle height just enough to maintain the anterior chamber.
► Changing to a 15-degree phaco needle or flatter, for maximum occlusion and followability of the nucleus.
With those measures in place, “careful phaco may be successfully employed to bring the subluxated piece into the anterior chamber for deconstruction and removal,” Dr. Silverstein says.
Sina Sabet, MD, of Alexandria, Va., notes that the late Charles Kelman, MD, the father of modern phaco, proposed the posterior-assisted levitation (PAL) technique for dropped nuclei, where a second instrument is placed, often through a pars plana incision, behind the lens fragment, to bring up the lens fragment into the anterior chamber for further phacoemulsification. More recently, Dr. Chang has suggested viscoelastic levitation to stabilize the nuclear fragments.
Dr. Sabet's invention, the Sabet Safety Net (Figure 3), is designed to aid the anterior segment surgeon in the management of dropped nuclear fragments intraoperatively The bore of the instrument fits smoothly through a paracentesis incision. If desired or necessary, a pars plana incision can also be used. When the button is depressed, four malleable metallic wires exit through the bore and fan out, providing an area of support measuring approximately 6 mm at its widest point. This provides stability for the lens fragments and allows them to be brought up from the vitreous cavity into the anterior chamber or iris plane. It also allows vitrectomy and phacoemusification to continue without any need to enlarge the incision.
Figure 3. The Sabet Safety Net is a tool that is designed to retrieve dropped lens fragments.
Rock-hard Nucleus
Although the lens density is identified preoperatively when an ultra-brunescent lens is accompanied by weak zonules, Dr. Chang says the odds of a capsular or zonular tear increases exponentially. “Every surgeon employing phacoemulsification in these cases should be prepared to convert to a manual extracapsular procedure if the zonules or posterior capsule appear to have become compromised,” he says.
“The necessary skill set is becoming more difficult to attain for the current generation of residents whose cataract training is sometimes exclusively in phacoemulsification.”
Dr Chang advises that a retrobulbar or peribulbar block should be considered in eyes with rock hard nuclei for this reason.
Posterior Capsular Rupture
Once the posterior capsule is compromised, the surgical priority becomes the removal of all nuclear material.
“Some surgeons will be comfortable using a PAL technique where appropriate,” says Dr. Chang. “I have described a technique called the Viscoat Trap, whereby a dispersive OVD is used to suspend free-floating lens material within the anterior chamber once vitreous prolapse has occurred.”
A bimanual anterior vitrectomy can then be performed by placing the split-infusion cannula through a limbal paracentesis, and the vitrectomy tip through a pars plana sclerotomy. The latter is positioned and visualized right behind the anterior capsule where all the transpupillary strands of vitreous can be severed without evacuating the dispersive OVD that fills the anterior chamber.
“As supporting vitreous is removed, the lens fragments remain anteriorly trapped and suspended by the dispersive OVD, so that they can be subsequently aspirated with bimanual I&A instrumentation,” Dr. Chang concludes.
“One thing we have seen recently is an increase in posterior capsular tears in those patients who have undergone Avastin injections prior to undergoing cataract surgery,” says Dr. Rivera. “I'm wondering if any other surgeons have seen this, but in our center as many as 60% to 70% of our capsular ruptures occur in this type of patient.”
One obvious concern is that the posterior injection may somehow weaken the posterior capsule, whether mechanically or pharmacologically, though Dr. Rivera has not seen this reported in the literature. He reports that the capsular rupture unfortunately occurs at the moment of hydrodissection, making the rest of the case exceptionally difficult in terms of maintaining the lens in the anterior segment.
Dr. Rivera says PAL of the nucleus may help, but there is often such a loss of posterior capsular integrity that lens fragments are retrodisplaced and the patient is subsequently referred for vitreoretinal surgery and retrieval of retained lens fragments.
“In all of these cases, my approach is to clean the remaining capsular bag of all residual cortical material using a low-flow Simcoe manual irrigation/aspiration technique and place a three-piece lens in the sulcus,” says Dr. Rivera.
Dr. Dewey invented the Dewey Radius Tip after being involved in research into various aspects of cataract removal, IOL design and IOL insertion.
“In looking at phaco needles, I concluded that, with the newer generation of phaco equipment, you didn't need a sharp edge to remove a cataract,” notes Dr. Dewey. “You could have a rounded edge and protect the capsule from breaking if there was contact with the phaco tip.”
Dr. Dewey says his rounded tip can be used with even the hardest nuclei.
Hemorrhage
Suprachoroidal or retrobulbar hemorrhages are truly in the category of the most horrifying intraoperative complications, says Dr. Silverstein. These can be caused by an undetected perforation, perhaps from retrobulbar or postop injection, or from the sudden equalization of intraocular/atmospheric pressure.
Immediately:
► Loosen the tension on the lid speculum.
► Administer 500 mg of Diamox and 25 grams of Mannitol IV (if the patient has no systemic contraindications).
► Release some fluid in from the anterior chamber and rapidly sew the wound closed securely.
► If the IOL is stable and centered, even if the chamber is flattening, leave it in place, as this may help avoid an unnecessary secondary procedure and potentially hold back the prolapsing vitreous.
► Consider a lateral canthotomy if a retrobulbar hemorrhage is suspected.
► If the posterior capsule spontaneously ruptures, very carefully remove any vitreous that presents at or above the iris plane. Do not attempt, via an anterior or a pars plana approach, to debulk the vitreous, as retina may quickly follow in this scenario.
► Administer two rounds of pressure-lowering topical agents (and antibiotics prior to discharge and referral) as tolerated.
► Call and immediately refer to a retina specialist.
Most of these cases may be observed, with early hospitalization for pain and IOP control, as the blood liquefies over the first one-to-two weeks.
Complications Are Learning Experiences
The reason that the top surgeons quoted in this article are able to offer specific guidance in dealing with intraoperative complications is because they have encountered these problems themselves. Thus, no cataract surgeon — however skilled or experienced — is immune from being confronted with these difficult cases. The best surgeons learn from problem cases and become adept at identifying and handling these issues when they arise again. It is the ability to coolly respond in the critical moment that separates the best cataract surgeons from the rest. OM
| More Insights on Managing Intraoperative Complications |
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“One of the most common preop conditions that can lead to problems intraop is Fuch's dystrophy — in which people can have pre-existing corneal edema, or can develop corneal edema postop. This can make it more difficult to see during the cataract surgery, though trypan blue can be used to mitigate this issue. If the corneal edema is thought to be mild enough to be compatible with good vision postop, then cataract surgery alone can be considered. If it is thought that it will affect the vision postop, then it is reasonable to consider combining the surgery with a DSEK when cataract surgery is done.” — David Hardten, MD, Minneapolis “Wound leak causing poor seal during phaco and l&A, leading to chamber instability, can be an intraoperative issue. If raising the bottle height maximally does not stabilize the chamber and prevent posterior capsular trampolining, the surgeon's options include: ► Putting a larger sleeve on the phaco needle or I&A tip. — Steven Silverstein, MD, Kansas City, Mo. “The best approach toward complications is to prevent them in the first place. Sometimes the simplest things can make huge differences. Patient movement is one of those situations that can rarely lead to devastating complications during cataract surgery — a sudden cough or head movement can lead to capsular rupture and worse. It also just adds to the stress level during surgery. Sometimes a twitchy patient can make it seem like you're trying to grab a greased coconut floating in the ocean. After I position my patients under the operating microscope, I take a 2- to 3-inch wide strip of nylon tape and wrap it around the patient's head and the bed. This does two things. First, it prevents the head from drifting during surgery, eliminating the ongoing need to reposition the patient's eye or the microscope. Second, it makes it very difficult for any sudden movements to be translated toward the instruments. Sure, the head might still move, but it's a lot less likely to move suddenly toward the instruments when the head is strapped down to the bed. It's such a simple thing to wrap a piece of tape around the patient's head, securing it to the bed. It's been one of the additions to my pre-surgical technique that makes things much more relaxed during the surgery. It adds an element of peace of mind.” — David Khorram, MD, Saipan, Mariana Islands “During capsulorhexis, periodically the capsular tear heads south, and can lead to lens dislocation and/or a dropped nucleus if the tear extends beyond the equator. First, as a matter of protocol, since overweight patients have a greater tendency toward developing this complication, the anesthesia and nursing staff in pre-op always know to administer IV Diamox (500 mg) and Mannitol (12.5 grams) in the holding area when the patient checks in, to lower the intraocular and posterior vitreous pressure as a preventative technique. If an aberrant tear develops, stop the capsulorhexis immediately, loosen the tension on the lid speculum and hyperinflate the anterior chamber with viscoelastic. Then, carefully complete the rhexis, taking multiple purchases of the capsular leaflet just ahead of the tear, regrasping frequently in order to control the direction and extent of the rest of the rhexis. — Steven Silverstein, MD, Kansas City, Mo. “I live in an area where there are a lot of short axial lengths with shallow anterior chambers. These patients can have positive vitreous pressure and can even go into angle closure when dilated. I have dealt with so many of these that I now rarely do a vitreous tap. Should an eye have palpably increased IOP, I give IV Mannitol and try to make my wound more anterior. I firmly believe that microincision phaco (2.4 mm or smaller) is safer in these cases. After carefully performing a relatively small (4.5 mm to 5.0 mm) capsulorrhexis under Discovisc or Healon 5, I carefully debulk the nucleus prior to any hydrodissection. After creating more space in the anterior and posterior segments with the debulking, I hydrodissect and complete the removal of the nucleus. It is important to do these cases as efficiently as possible in order to decrease the likelihood of a choroidal effusion. I have become so comfortable with addressing these eyes in this fashion that lens removal has become my treatment of choice for narrow angles.” — Johnny Gayton, MD, Warner-Robins, Ga. |
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