Surgeon: Phaco chop technique with micropulse saved energy

WASHINGTON — A phaco chop technique using micropulse ultrasound and varying duty cycles used less energy than a standard continuous phaco technique, said a speaker here.

“The chop surgical technique, together with the ultrasound modifications, really makes a difference,” said Steven H. Dewey, MD, in a presentation at the American Society of Cataract and Refractive Surgery meeting.

He presented the results of a study on 335 eyes comparing two techniques: continuous ultrasound phacoemulsification with the Advanced Medical Optics Sovereign WhiteStar System using a divide-and-conquer cataract extraction technique, and micropulse or “varied” ultrasound phacoemulsification with a chop technique.

“The micropulse ultrasound setting, marked by small bursts of energy followed by small rests, is safer for the patient because it reduces the risk of wound burn,” Dr. Dewey noted. For patients undergoing the chop technique with micropulse ultrasound, the duty cycle was reduced to between 25% and 35%, he said.

Dr. Dewey found that the divide-and-conquer group with continuous ultrasound “demanded far more” energy than the chop group with varied ultrasound. In fact, Dr. Dewey said, the continuous ultrasound group required “three times as much energy” as the variable ultrasound group.

“There was a 3-to-1 ratio of power efficacy after all variables were considered,” he noted.

While the varied ultrasound group required less energy than the continuous group, Dr. Dewey said that the chop technique slowed the procedure down, adding an extra 12 to 15 seconds per case.