I designed my divide-and-conquer technique to minimize complications during phacoemulsification, particularly posterior capsule rupture. The first step is to develop a proper capsulorhexis. Next, the surgeon must perform an excellent hydrocortical cleavage.
I. Howard Fine, MD, of Eugene, Oregon, originated this technique, which requires a flat, spatula-type cannula (I use a 25-gauge) to inject BSS (Alcon Laboratories, Fort Worth, TX). The key to obtaining the proper cortical cleavage is carefully placing the cannula underneath the anterior capsule, rather than somewhere in the cortical layer, before injecting any fluid.
SEPARATING THE NUCLEUS AND CORTEX FROM THE CAPSULE
Once the cannula is in the proper location, I slowly inject the fluid and wait for what is called a delayed fluid wave. If the surgeon does not see this wave, he should continue injecting fluid, or possibly try another location until he sees the fluid wave. When the wave starts to cross the visual axis, the nucleus will begin to prolapse anteriorly. Before it prolapses out of the capsular bag, I apply downward pressure on the nucleus with the cannula, which causes the fluid wave to continue across the rest of the visual axis, separating the nucleus and cortex from the capsule. I verify this separation by rotating the nucleus with the tip of the cannula to ensure that it is mobile.
PHACOEMULSIFICATION
The surgeon must make sure that there is I/A present before entering into the phacoemulsification mode; failure to do so could precipitate a thermal injury to the incision. Once I establish that I have I/A, I sculpt the nucleus into perpendicular grooves. I sculpt to a depth of approximately 60% in normal cataracts and about 80% in extremely brunescent cataracts. To judge the sculpting depth, consider that 60% is equal to about 1.5 times the thickness of the phaco tip, and 80% equals about twice the thickness of the phaco tip. I use a Kelman 30&Mac251; Microtip (Alcon Laboratories) and the ABS (aspiration bypass system) attached to the Legacy Phaco Emulsifier System (Alcon Laboratories), and I use the Advantec software (Alcon Laboratories), which allows a linear response at the lower levels of phacoemulsification power.
SPLITTING THE NUCLEUS
As I achieve the perpendicular grooves, I am careful to remain within the borders of the capsulorhexis. This precaution will prevent me from inadvertently catching the anterior capsule and causing the tear, which can extend posteriorly. Next, I use a pair of cracking forceps (Ernest Nuclear Crackers; Katena Products, Inc., Denville, NJ) under a coating of viscoelastic (Figure 1). The advantage of these forceps is that they have a wide surface area that provides excellent purchase on the sides of the grooves, and they are also cross-action so that they work in an incision of 2.5 mm. With an excursion that extends to 4 or 5 mm, I achieve a very reproducible and definite split of the nucleus. Also, the paddles on the forceps have a posteriorly tapered edge for easy removal from the internal aspect of the corneal incision.
After splitting the nucleus, I rotate it and continue to split until I am sure that all four quadrants are separated from one another. In dense, brunescent cataracts, I emphasize the importance of ensuring that the central part of the nucleus splits so that the nucleus is disassembled. I use the phaco handpiece under aspiration levels of 400 to 450 mm Hg and flow rates of 45 cc/min to engage the quadrant, pull it toward the center and away from the corneal endothelium, into the iris plane, and then emulsify it (Figure 2). I perform these maneuvers on each quadrant separately. After removing and emulsifying all four quadrants, I perform cortical cleanup using a bimanual technique prior to inserting the lens.
Paul Ernest, MD, is in private practice at TLC Eyecare of Michigan in Jackson, Michigan. He holds no financial interest in any product mentioned herein. Dr. Ernest may be reached at (517) 782-9436; paul.ernest@tlcvision.com.
