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Using the strengths of both peristaltic and venturi phaco, a modified chop technique increases efficiency and safety in denser nuclei.
Using the strengths of both peristaltic and venturi phaco, a modified chop technique increases efficiency and safety in denser nuclei
By Dwayne K. Logan, MD; Special to Ophthalmology Times
My cataract practice serves a predominantly geriatric, managed-care patient population, in whom denser nuclei are common. Over the years, I’ve sought more effective techniques for dealing with these cataracts.
Recently, I have modified my chopping technique to take advantage of the combined strengths of peristaltic, venturi, and transversal phaco to enhance safety and efficiency. This technique, which I will call “pizza-pie chop,” is made possible by the unique combination of technologies in a phaco platform (WhiteStar Signature System, Abbott Medical Optics).
After making my corneal incisions and capsulorhexis, I begin the phaco portion of the procedure in chop mode, using the system’s peristaltic pump. This pump mode allows me to increase the vacuum safely without proportionally increasing flow, so that I can maximize holdability of the nucleus while I chop.
While holding the phaco tip in the center of the lens, I slide my chopper around the equator of the lens and under the capsule and iris, pulling it toward the phaco tip to chop the nucleus in half. I rotate the lens 90° and chop again, then continue spinning clockwise and chopping each quarter segment into three pieces, until I end up with 12 pizza wedges. The chopper remains under the anterior capsule as I’m chopping and rotating.
Many surgeons would elect to emulsify each segment as it is chopped. My preference with this system is to do all the chopping first, before beginning segment removal. Although I chop the nucleus into a lot of pieces, this can be done safely and efficiently when the chopper remains relatively stationary in the capsular bag and behind the equator, rather than drawing it out each time to emulsify the segment.
Once I have my 12 slices of pie, I switch to the quadrant removal setting, which automatically switches the system from the peristaltic to the venturi pump, and increase the flow. As I remove each segment, beginning 180° away from the insertion of the phaco tip, or at about the 6 o’clock position, I don’t move the phaco tip at all but simply let the venturi fluidics draw each piece to the phaco port. I use the second instrument under the bag to manipulate the pieces, rotating in a clockwise manner until all 12 segments have been emulsified.
Using venturi for this portion of the surgery has eliminated the need to “chase” the pieces around the anterior chamber-they simply roll right into the phaco port. The transversal phaco (Ellips FX), combined with the venturi fluidics, ensures that there is never full occlusion, which also keeps the chamber very stable.
As I move into irrigation and aspiration, the drawing power of venturi fluidics continues to be an advantage, as it allows cortical material to move towards the tip with very little manipulation. I can maintain the tip in a stable, more anterior position, away from the iris and posterior capsule, and still be confident of a thorough cortical cleanup.
This is an efficient procedure that minimizes effective phaco time and the amount of phaco power used, which helps to reduce postoperative edema and the risk of complications. Each pump is used most appropriately, according to its strengths.
At one clinic I use both the Signature system and the Infiniti system (Alcon Laboratories). With the latter, I don’t have the flexibility to switch between peristaltic and venturi pumps. So I have to go back to my old technique, alternating between chopping and segment removal with the peristaltic pump. The higher vacuum of the Infiniti peristaltic pump is ideal for the very hardest nuclei-which it can cut through and emulsify smoothly-but otherwise, that high vacuum can be detrimental. It also demands additional manipulation of the tip to break occlusion as segments get “stuck” and then of the secondary instrument to help re-engage the segment. For most cases, I prefer less movement and manipulation with the dual-pump approach.
When I review my own surgical videos it is evident how much less movement and maneuvering there is with my current pizza-pie chop technique, compared to the more traditional chop-remove-chop technique.
For someone operating primarily on very soft lenses, technique may be less important. But in my geriatric population, I find that this pizza-pie technique helps to keep the chamber very stable and prevent those nuclear segments from moving around and damaging the capsule.
Whether surgeons adopt this specific technique or not, I believe that anyone who is currently performing a variant of phaco chop will quickly appreciate the safety and efficiency advantages of venturi fluidics for removal of the chopped segments. In addition, venturi can facilitate the transition to chopping for those who currently sculpt the nucleus.
Dwayne K. Logan, MD
Dr. Logan is in private practice at Atlantis Eye Care in Long Beach, CA. He has no financial interest in the products mentioned. He is a consultant to Abbott Medical Optics for speaking events.