Surgeons offer pearls for traditional coaxial, bimanual phaco techniques for dense cataracts
Skill and experience, combined with careful evaluation, are necessary for dealing with rock-hard cataract extraction.
ROME – Modern phacoemulsification is able to deal with even the hardest nuclei, but only skill and experience can ensure safety and prevent complications, according to surgeons speaking here. At the meeting of the Italian Society of Cataract and Refractive Surgery, held during the ESCRS Winter Refractive Meeting, two surgeons offered suggestions to the audience on how to make both traditional monomanual phaco and bimanual microincision cataract surgery (MICS) a success with rock-hard nuclei.
Alessandro Galan, MD, recommended the use of trypan blue because dense nuclei hide the red reflex of the retina. After hydrodissection, he suggested the use of a chop technique, which “saves on ultrasound and allows more safety and comfort during surgery.”
“I wouldn’t recommend tackling a dense nucleus with a groove. Although embedding the phaco tip vertically in the nucleus might not be easy, with a good phaco machine everyone can learn how to do it. The important thing is to direct the phaco tip downwards, and make it penetrate into the nucleus as much as it’s needed to get a good grasp on it,” he said.
Images: Panzardi G
The target should be more or less the nucleus equator, and it is important that the surgeon knows beforehand how deep he or she wants to embed the phaco tip.
“These kinds of nuclei usually have a diameter of 3 mm to 4 mm; therefore, if you push your tip down to about 2 mm you are within safe limits. Before you start, draw back the sleeve about 2 mm, and when the sleeve touches the nucleus, you’ll know the tip has reached the level you wanted,” Dr. Galan said.
Cracking the nucleus
Once the phaco tip is firmly embedded, the chopper and the tip can be gently pushed toward each other to crack the nucleus.
Dr. Galan said that the first crack is the most difficult step of the procedure because the bottom layers of a dense nucleus tend to form a shield that prevents the nuclear fragments from being separated and directed toward the center and emulsified.
He pointed out that the phaco tip and chopper should be maneuvered with equal intensity. In these cases the chopper plays a more active role than with softer nuclei, continually chopping the nucleus and directing the fragments toward the phaco tip.
A problem that frequently occurs at this stage, even with the most advanced phaco machines, is the blockage of the phaco tip. The first sign is that the aspiration flow starts decreasing, and the surgeon should be able to detect this immediately, to avoid using an excessive quantity of ultrasound in the attempt to aspirate the fragments.
“The only thing to do is withdraw, find out where the occlusion is, release the blockage with a syringe and start again,” Dr. Galan said.
Dealing with very dense nuclei requires a much longer phaco time — almost double that of a normal procedure — and surgeons should never rush their maneuvers.
“You need patience, care and extreme caution,” Dr. Galan recommended.
Posterior capsule protection
The epinucleus, which provides a cushion-like barrier in normal cataract surgery, becomes an inseparable part of the dense nucleus in hard cataracts, and the surgeon should be aware that there is nothing in between the masses that are being emulsified and the posterior capsule, according to Dr. Galan.
“Moreover, because the nucleus is larger than normal, the capsule is often weak, fibrotic and stiff and therefore easy to break,” he pointed out.
A useful technique for creating an artificial epinucleus is injecting a cushion of adhesive viscoelastic behind the nucleus, he said. After partial removal of the fragments, the surgeon can stop emulsifying, find a passage behind the nucleus and inject the viscoelastic.
“This also requires some extra time but adds a lot of safety to your procedure,” Dr. Galan pointed out.
With 5+ nuclei, he recommended the use of a small quantity of adhesive viscoelastic also at the beginning of the procedure, to protect the endothelium, followed by an injection of cohesive viscoelastic.
“I do this double filling because the adhesive viscoelastic tends to trap the nucleus fragments. Some of them tend to get hidden in some nook of the capsular bag and appear later in the anterior chamber, maybe the day after the procedure. Also, the adhesive viscoelastic captures air bubbles, which prevent you from seeing clearly into your operating area,” he said.
Advantages of small tips
In the hands of an expert surgeon, rock-hard cataracts can also be treated using a bimanual technique, according to Giuseppe Panzardi, MD.
“Extreme cases are fortunately quite rare. Surgeons, and particularly less expert surgeons, should evaluate their personal capabilities and choose the technique they are able to manage safely. Removing the cataract at the price of causing some kind of corneal or zonular damage is something that should be definitely avoided,” he said.
Bimanual microincision cataract surgery, once the surgeon has mastered the technique, is the safest and easiest way of dealing with very dense nuclei, Dr. Panzardi said. The phaco tip is small and therefore penetrates more easily into the nucleus, using a minimum quantity of ultrasound.
“Contrary to what one may think, small tips also get blocked less easily than larger tips. This is because obstruction occurs at the pump rather than at the tip level, and the small fragments that enter through the tiny aperture of small tips are just not large enough to clog the pump. I had a few cases of blockage with traditional phaco, but none with bimanual MICS,” Dr. Panzardi said.
He recommended using a venturi rather than a peristaltic pump for bimanual surgery. With conventional phaco he said he preferred a peristaltic pump, which gave him flow as well as vacuum control, but because a small tip requires a lower flow rate, the venturi pump can be used without the risk of losing stability in the anterior chamber.
“In bimanual surgery, the venturi mode is safe and faster than the peristaltic mode,” he said.
Hard nuclei should be emulsified keeping the microtip in the center, where it has been first embedded, Dr. Panzardi said. This makes surgery easier also in patients with small pupils. Fragmentation may be difficult in the hard bottom layers of these nuclei.
“Fortunately, most of these cases are highly myopic eyes with a deep anterior chamber. In some cases it may be better to rotate the nucleus upside down, in order to tackle the bottom shield more directly with the tip,” Dr. Panzardi suggested.
With these few adjustments, bimanual microincision surgery is feasible with even the hardest nuclei, he said.
“It is safe and effective, and I have never had cases of burns, even with black cataracts,” he said. “All you need is to be familiar with the technique and to take more time because the procedure is necessarily slightly longer than conventional phaco. Time and patience are, however, basic requirements for any kind of complicated cataract surgery.”
ECCE an option, but planned
Both surgeons agreed that extracapsular cataract extraction (ECCE) remains a viable alternative to phaco in case of rock-hard cataracts.
“A good ECCE is better than a clumsy phaco,” Dr. Panzardi said.
In his opinion, if a surgeon doesn’t feel confident enough to perform phacoemulsification in these difficult cases, he or she should plan in advance to do an extracapsular extraction.
“The incision is larger, astigmatic recovery is slower, but the procedure is safe, and I don’t see why it should be necessary to carry out a phaco at all costs,” he said.
Dr. Galan agreed that ECCE is better planned in advance than used as an emergency measure during an unmanageable phaco procedure; however, if the need to convert from phaco to ECCE arises, he enlarges the original phaco incision.
“The problem is that you end up with an incision that is completely in the cornea, because the conjunctiva has not been previously detached. Moreover, the patient is likely to be under topical anesthesia. I usually take the time to inject 2 cc of lidocaine deep in the [lacrimal] caruncle, in order to paralyze the three oculomotor nerves. I wait 1 minute and then start enlarging the incision,” he explained.
“Conversion never produces good surgical results, and I know that it is entirely my fault since I had not planned it in advance, probably because I have not carefully evaluated which was the best and safest option for that particular case,” he said.
As both surgeons emphasized, being overconfident with rock-hard cataracts can lead to disappointing results.
For Your Information:
- Alessandro Galan, MD, can be reached at Ospedale Civile Sant’Antonio, Via Facciolati 121, Padova, Italy; +39-049-8216780; fax: +39-049-8216541; e-mail: firstname.lastname@example.org. Dr. Galan has no direct financial interest in any products mentioned in this article, nor is he a paid consultant for any companies mentioned.
- Giuseppe Panzardi, MD, can be reached at Day Surgery “M. Bufalini” – Palazzo Capponi, Via Gino Capponi 26, 50121 Florence, Italy; +39-0550244950; fax: +39-055-2345089; e-mail: email@example.com; www.centrobufalini.it. Dr. Panzardi has no direct financial interest in any products mentioned in this article, nor is he a paid consultant for any companies mentioned.