‘Earthquake’ approach a modification of familiar techniques

A modification of phaco-flip techniques works from the inside out to make phaco faster and safer.

Issue: August 1, 2001

ByYair Karas, MD, FRCS(C)

When it comes to lens emulsification, surgeons usually suggest the outside-in approach. That is, phaco energy is initially applied to the peripheral part of the nucleus.

Recent reports have described the phaco-flip technique (David Brown, MD, and Richard Livernois, MD) and the tilt-and-tumble technique (Richard Lindstrom, MD) as modifications of the supracapsular technique of William Maloney, MD.

I have performed more than 300 cases in the past few months using the reverse approach. I use the flip technique, but I first emulsify the lens inside-out by creating an “earthquake” in the center of the nucleus with the first burst of phacoemulsification. I then emulsify the rest of the nucleus.

Using this method, the phaco starts at the center of the nucleus, which, after the flip, is located in the center of the pupil in the pupillary plane, so that the rest of the nucleus initially protects the endothelium and the posterior capsule.

Technique

A clear corneal incision and paracentesis are created 150° to 180° apart. A capsulorrhexis of 5 mm to 6 mm (not less) is created using viscoelastic. Hydrodissection is performed until the lens is tilted out of the bag. If this is not accomplished, the technique is aborted, and I revert to the usual cracking or chopping in the bag, or I tilt it by injecting viscoelastic under the nucleus, as per Dr. Lindstrom.

From this point, I believe I begin to differ from the other surgeons.

With the lens tilted approximately 45°, one pole is on the posterior capsule and the other in the anterior chamber. The lens is rotated with the hydrodissection cannula until the back side faces the paracentesis and the front side faces the clear corneal incision (figure 1).

The nucleus rotator is introduced through the paracentesis and parallel to the iris into the back part of the lens, directed to the center of the nucleus, which is located in the center of the pupil in the pupillary plane (figure 2).

The phaco tip is introduced through the clear corneal incision and pushed parallel to the iris into the front surface of the tilted lens (figure 3).

Both instruments are pushed simultaneously until they meet in the center of the lens. No phaco has been used so far. This maneuver may in itself crack the lens when very hard nuclei are encountered (figure 4).

An “earthquake” is created in the center of the nucleus. This is achieved by activating the phaco machine using high vacuum (350 mm Hg), 50% ultrasound power and pulse mode. The dead center is instantly disintegrated, and part of the nucleus is cracked (figure 5).

The center of the nucleus is removed, and the rest of the nuclear material is emulsified using chopping. The phaco tip is repeatedly introduced into the remnant of the nucleus, all the while remaining in the “safety zone,” with the second instrument chopping it into small fragments, which are mostly aspirated. Very little phaco energy is required.

I find that it takes seconds of phaco time — almost always less than a minute — to address even the hardest nuclei, as opposed to much longer phaco time with other techniques. The procedure is safer because it is performed away from the posterior capsule, without tension on the zonules, and away from the endothelium.

I now have much less respect for hard nuclei. I still get some cases of corneal edema, which dissipates in the first few postoperative days, but I feel that I am certainly performing a safer procedure. After 25 years in practice, I walk into the operating room much more relaxed.

I would like to thank Robert Gervais, MD, and Tomer Karas, MD, for their helpful comments.

The lens is rotated with the hydrodissection cannula until the back side faces the paracentesis and the front side faces the clear corneal incision.

The nucleus rotator is introduced through the paracentesis and parallel to the iris, directed toward the center of the nucleus, which is located in the center of the pupil in the pupillary plane.

The phaco tip is introduced through the clear corneal incision and pushed parallel to the iris into the front surface of the tilted lens.

Both instruments are pushed until they meet in the center of the lens. No phaco has been used so far. This maneuver may in itself crack very hard nuclei.

An “earthquake” is created in the center of the nucleus by activating the phaco machine. The center is instantly disintegrated, and part of the nucleus is cracked.

For Your Information:

Yair Karas, MD, FRCS(C), a diplomate of the American Board of Ophthalmology, can be reached at 10014 Yonge Street, Richmond Hill, Ontario L4C 1T8, Canada; (905) 884-2020; fax: (905) 884-9187; e-mail: drkaras@karasvision.com. Dr. Karas has no direct financial interest in any of the products mentioned in this article, nor is he a paid consultant for any company mentioned.