Quick-chop technique safer for smaller pupils, surgeons say

The technique emphasizes manual nuclear dissection and aspiration of disassembled pieces with high vacuum pressure.

A variation of the phaco-chop technique can make cataract extraction easier and possibly safer for eyes with smaller-than-average pupils, according to two surgeons.

David Dillman, MD, a cataract surgeon in private practice in Danville, Ill., said the quick-chop technique is useful for operating on patients with smaller pupils because most of the action takes place centrally.

“I’m not saying tiny pupils. But for the smaller pupils that are still reasonable, this technique requires less space so you can work with the smaller pupils,” he said.

According to Dr. Dillman, in traditional chopping, the chopper is positioned under the anterior capsule, out toward the periphery. With quick-chopping, the surgeon can basically ignore the anterior capsule and simply place the chopper in the center of the eye, on top of the buried phaco tip.

“The orientation is just so much easier. And I think that makes it safer,” he said.

William F. Maloney, MD, a cataract and refractive surgeon practicing in Vista, Calif., said the poor visibility often experienced in the periphery of the lens is avoided with the use of the quick-chop technique.

Dr. Maloney said the other forms of chopping risk engaging the capsule and other events the surgeon cannot directly visualize.

“This quick-chop technique is primarily advantageous because it eliminates that problem,” he said.

He said nuclear separation also is usually easier to accomplish. Typically, quick-chop causes a complete separation of the nucleus into two distinct halves without any residual separations, a problem often experienced with the traditional phaco-chop.

According to both surgeons, the quick-chop technique works equally well in the supracapsular or the endocapsular approaches, but it works best when there is an identifiable endonucleus at the slit lamp of grade 2+ or higher.

Technique

The original phaco-chop technique described by Nagahara is essentially a horizontal chop. The surgeon places the hook in the periphery of the lens, imbeds it into the periphery and then drags it into the center, creating a separation horizontally.

“I think the key element to differentiate [quick-chop] is that the separation occurs from top to bottom, not from outside to inside, and is therefore a vertical chop,” Dr. Maloney said.

Dr. Dillman began using this variation of chopping in 1996 after seeing a video featuring the phaco-crack technique of Vladimir Pfeifer, MD’s, at that year’s annual meeting of the American Society of Cataract and Refractive Surgery.

Both surgeons said the technique was also concurrently developed by Hidaharu Fukasaku, MD, in Japan, independent of Dr. Pfeifer.

The procedure involves using pulsed phaco power to imbed the tip firmly into the center of the nuclear material. To accomplish this, the tip is extended slightly farther out from the sleeve than traditionally required.

“So, instead of a 1-mm tip extending from the infusion sleeve, you’ve got approximately 1.5 mm. That gives you a little bit more purchase on the center of the nucleus,” Dr. Maloney said.

The quick-chopper comes in from the side port and is imbedded into the nuclear material immediately above the phaco tip once the phaco tip is imbedded into the nucleus. The two instruments are then displaced in opposite directions, creating a vertical full-thickness split from top to bottom.

According to Dr. Maloney, once the nucleus is divided in half, the sequence of further separation and evacuation basically follows the traditional manner.

“The amount of separation you do is typically proportional to the density of the nucleus. The harder the nucleus, the more subdivisions and the more separations you make because you want the pieces to be smaller, almost bite-sized or tip-sized, so they can be aspirated more easily,” he said.

Dr. Maloney said quick-chop emphasizes manual dissection of the nucleus and then aspiration or phaco-assisted aspiration of disassembled pieces. Machine settings vary depending on whether a Venturi pump or a peristaltic pump machine is used.

“I use the Millennium (Bausch & Lomb Surgical, a Venturi pump machine) and I find that my settings are approximately 80 mm Hg, which is fairly high aspiration. That allows me to mobilize and evacuate each of these disassembled pieces with little or no phaco power,” Dr. Maloney said.

Dr. Maloney said ultrasound is used mainly as “sort of a supplementary unclogging of the vacuum line” when a piece gets stuck on the tip and does not follow through.

Learning curve

Dr. Dillman said there is a slight learning curve involved in switching over to the quick-chop. However, it is not as great as with other techniques.

“I tried [Dr. Nagahara’s] technique several times but I never got very fast at it. So I thought there was a significant learning curve with traditional chopping. I think the learning curve is considerably less with quick-chopping,” he said.

He added that one of the advantages of trying a quick-chop procedure is that “you don’t ever phaco yourself into a corner from which it’s hard to get out.”

Dr. Dillman said a surgeon accustomed to using a traditional divide-and-conquer technique who is in the learning curve with the quick-chop can actually try the quick-chop technique up to three times and is still able to revert back to a divide-and-conquer technique if none of the quick-chop attempts are successful.

“So if it doesn’t work, it’s not like an oh-my-God-what-am-I-going-to-do-next situation. I find that very satisfying,” he said.

Equipment

Dr. Maloney explained one problem experienced early in the development of quick-chop was difficulty generating enough separation force in the opposite direction to create the split in very dense, hard nuclei.

“I found part of the problem was not being able to firmly imbed the chopping instrument into the nuclear material itself. The chopper was sort of scratching off or sliding off the side or surface of the nucleus. Therefore, you couldn’t generate enough displacement forces,” he said.

He said that led to the development of a version of the chopping instrument, the Maloney Quick-Chopper (Bausch & Lomb Surgical).

“One side of it is a traditional chopper and the other side is more tapered like a pin so it will more easily imbed into harder nuclei,” Dr. Maloney said.

Other surgeon-designed chopper versions are available from numerous instrument manufacturers.

Dr. Dillman said the technique doesn’t require any specialized equipment.

“You can quick-chop with virtually any machine on the market,” he said.

However, he added, quick-chopping is very dependent on having good vacuum and flow.

“Today’s machines are much better than the older machines. Any of the modern machines would lend themselves well to quick-chopping,” he said.

For manipulating the nucleus, Dr. Dillman said he uses a chopper designed by Paul Koch, MD. Versions of the chopper are available from various manufacturers.

The vertical quick-chop is accomplished by slightly elevating the embedded phaco tip while depressing the embedded quick-chopper. (All figures courtesy of William F. Maloney, MD.)
Each nuclear half is further divided into quarters using the same quick-chop maneuver.	Further division of each nuclear quadrant is often helpful in the more dense nuclei.
Sequential disassembly and evacuation takes place routinely.
Sequential disassembly and evacuation continues with the remaining quadrants.

For Your Information:

• David Dillman, MD, can be reached at Dillman Eye Care Associates, 600 N. Logan Ave., Danville, IL 61832; (217) 443-2244; fax: (217) 443-6779. Dr. Dillman has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.
• William F. Maloney, MD, can be reached at 2023 West Vista Way, Suite A, Vista, CA 92083; (760) 941-1400; fax: (760) 941-9643. Dr. Maloney has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.
• Bausch & Lomb Surgical, makers of the Maloney Quick-Chopper and the Millennium microsurgical system, can be reached at 180 Via Verde Drive, San Dimas, CA 91773; (800) 338-2020; fax: (800) 362-7006.