Incremental steps help transition from divide and conquer to phaco chop

Proceed at your level of comfort and be ready to revert to more familiar technique, a surgeon advises.

HOUSTON — Some surgeons may question the necessity of making the transition from divide-and-conquer to phaco chop in phacoemulsification. But the change is well worth it, according to L. Andrew Watkins, MD, who is in solo private practice here.

“Phaco chop is faster than divide-and-conquer, and there is no time-consuming sculpting involved,” Dr. Watkins said. The technique is also “potentially safer than divide-and-conquer for dense nuclei because, with a dense nucleus, there is a thinner epinucleus. Therefore, you’re closer to the posterior capsule when you go posterior in the nucleus.”

Other benefits of phaco chop are minimal use of ultrasound power (thus decreasing the risk of corneal burns or endothelial damage), decreased volume of fluid through the anterior chamber (minimizing the trauma to the endothelium) and ability to perform phacoemulsification in the iris plane. “And, it is excellent for denser nuclei,” Dr. Watkins said.

Dr. Watkins said there are two chopping variations: horizontal and vertical. “Horizontal chopping is best for softer to medium dense nuclei,” he said. “It is also best for the transitional surgeon.” On the other hand, “vertical chopping is better suited for harder, more brunescent nuclei. This is best attempted when you’re very comfortable as a bimanual phaco surgeon.”

Smooth transition

To make a smooth transition from divide-and-conquer to phaco chop, “you’ll be more comfortable with smaller, more incremental approaches to the ultimate goal,” Dr. Watkins said. “The first step is to master divide-and-conquer.” The second step is to master stop-and-chop. “Then, progress from stop-and-chop to non-stop phaco chop,” said Dr. Watkins.

“After becoming proficient and comfortable with horizontal chopping, you’ll want to become proficient and comfortable with vertical chopping of the densest, more brunescent cataracts,” Dr. Watkins said.

In classic four-quadrant divide-and-conquer, “the nucleus is deeply sculpted, rotated and sculpted again,” Dr. Watkins said. “After dividing the four quadrants mechanically with a second instrument, each of the quadrants is emulsified.” However, in stop-and-chop, “you stop the divide-and-conquer process after the initial groove is completed. The nucleus is hemisected, and you chop the remaining two hemisections.”

No initial groove

In non-stop phaco chop, there is no initial grooving. “You position your second instrument at the epinucleus,” Dr. Watkins said. “You grasp the nucleus with the phaco tip, and use the burst mode to impale the phaco tip into the nucleus. You bisect the core nucleus by compressing it between the chopper and the phaco tip.” Chopping is repeated to create wedge-shaped segments, and ultrasound is used to aspirate the segments sequentially.

Ideal patients

Dr. Watkins recommends that transitional surgeons begin with eyes that have “large pupils, good exposure, good visibility, good red reflex and a little arcus.” In addition, the surgeon should start with “medium-dense nuclei that are neither very soft nor very hard.” Patient cooperation is desirable if topical anesthesia is used.

A change in instrumentation may also be warranted. “A 0° phaco tip is ideal for chop, but a 15° tip is a good compromise that allows for either divide-and-conquer or chopping,” Dr. Watkins said. “If you’re currently dividing and conquering, you can change your second instrument to a chopper, which can be used for either technique.” Among the many choppers available, Dr. Watkins has enjoyed using the Chang Chopper from Katena Products Inc. (Denville, N.J.).

“Practice using your second instrument or chopper more frequently than you normally use a second instrument for your one-handed divide-and-conquer,” Dr. Watkins said. “I would recommend that you proceed at your level of comfort and revert or convert to your usual techniques as necessary.”

Phaco machine

Dr. Watkins advises using a phacoemulsification machine that has high vacuum capability along with burst mode capability. “Have your phaco parameters programmed in your phaco machine for ideal divide-and-conquer and for ideal phaco chop, so that you can switch back and forth as necessary or as desired,” he said.

A high-vacuum machine “engages the nucleus and holds it centrally,” Dr. Watkins said. “This will provide a stable environment as you introduce your second instrument.” A high-vacuum machine will also “give you precise control of ultrasound energy to break down the fragments for safe and controlled aspiration.”

Over the past year, Dr. Watkins has used the Sovereign phaco machine (Allergan Surgical) to help him make a successful transition. “There are a number of settings for phacoemulsification with the Sovereign,” he said. “There is a burst mode where you designate either single or multiple burst. It decreases the time in continuous power. It also enhances your ability to impale the nucleus.” In addition, the Sovereign has a continuous mode, a pulse mode and a power pulse. “The machine has a maximum vacuum from 0 mm Hg to 500 mm Hg, which creates enough holding force to elevate or remove chopped pieces,” Dr. Watkins said.

In the occlusion mode, “you can have high flow rates with one occlusion and low flow rates when the tip is unoccluded,” Dr. Watkins said. “You can also have immediate release of vacuum, which prevents a surge of fluid from the anterior chamber into the aspiration line.” Moreover, “phaco chop can be performed in the iris plane away from the posterior capsule and the endothelium.

“The Sovereign phaco machine uses new technology to provide excellent purchasing and holding power for efficient nuclear practice and removal with phaco chop,” Dr. Watkins concluded.

For Your Information:

• L. Andrew Watkins, MD, can be reached at 427 W. 20th St., Houston, TX 77008 U.S.A.; +(1) 713-862-6631; fax: +(1) 713-861-1410; e-mail: watkins@fc.net. Ocular Surgery News could not confirm whether or not Dr. Watkins has any financial interest in any of the products or companies mentioned in this article.