Torsional phaco likely to change cataract surgery landscape

"Torsional phaco is a revolutionary change in the way we do phaco," said Dr. Mackool, director of the Mackool Eye Institute and Laser Center, Astoria, NY. "Within the next 3 to 5 years, the majority of phaco procedures in the United States will be performed with torsional ultrasound."

Torsional phaco has two main advantages when compared with traditional ultrasound: efficiency in nucleus removal and safety in terms of reduced risk of thermal injury.

"Using the same flow and vacuum settings that the cataract surgeon might normally set for traditional ultrasound, he or she will notice that the nucleus is removed more quickly with torsional ultrasound," continued Dr. Mackool, who spoke during the meeting sponsored by Johns Hopkins University School of Medicine, Baltimore, and Ophthalmology Times.

"The nucleus appears to evaporate. It just disappears into the tip quickly because it doesn't just sit on the tip and microscopically chatter during removal. This difference between traditional and torsional ultrasound is particularly noticeable with more dense lenses," said Dr. Mackool, one of the clinical investigators who began evaluating the technology 15 months ago for Alcon Laboratories.

Use with dense lenses

Dr. Mackool explained that surgeons will experience the most time-savings using this system when applied to dense lenses. He did note that with extremely dense lenses (4+) there may be the need to use a combination of torsional and traditional longitudinal ultrasound to avoid occlusion of the handpiece tip. The problem may be caused by a large sheared-off piece obstructing the tip.

To avoid that problem, "the torsional handpiece can be programmed to deliver a percentage of the ultrasonic energy by the traditional to and fro method," he said.

"We simply push a button and switch from 100% torsional to a combination of 80% torsional oscillation and 20% traditional ultrasound," he said. "So it would be set to 80 msec on for torsional and 20 msec on for traditional."

Dr. Mackool noted that 98% of the time he uses just torsional ultrasonic energy and 2% of the time he switches to a combination of torsional and traditional ultrasound.

The torsional handpiece, weighing only 1.5 ounces, is one of the lightest handpieces available. Its tip is similar to other handpieces in that it is angled and tapered, so that the distal end is wider than the shaft. Different-sized infusion sleeves can be used with the handpiece, thus enabling a small incision of 2 to 2.2 mm, he continued.