Chapter 12

After clear corneal incision, cortical cleaving hydrodissection followed by hydrodelineation is performed. After the two hydro steps, the nucleus should rotate easily within the capsular bag. The 30-degree phaco tip is introduced bevel down to aspirate the epinucleus uncovered by the capsulorrhexis. For the superficial epinucleus as well as the chopping, low vacuum settings are utilized. The Fine/Nagahara chopper (Rhein Medical, Tampa, FL) is placed in the golden ring and is used to stabilize the nucleus by lifting and pulling toward the incision slightly (Fig. 12–1), after which the phaco tip lollipops the nucleus in either low pulse mode at 2 to 4 pulses per second or burst mode. The technique is remarkably efficient. This efficiency is achieved because the decrease in cavitational energy around the tip at this low pulse rate or burst mode allows the creation of a tunnel in the nucleus in which the tip is embedded and fits the needle very tightly. This produces an excellent hold on the nucleus. With the energy set in this way, the ultrasonic energy delivered into the eye is minimized while the hold on the nucleus is maximized.

The Fine/Nagahara chop instrument is grooved on the horizontal arm close to the vertical chop element, with the groove parallel to the direction of the sharp edge of the vertical element. In scoring the nucleus, the instrument is always moved in the direction the sharp edge of the wedge-shaped vertical element is facing (as indicated by the groove on the instrument), thus facilitating scoring. The nucleus is scored by bringing the chop instrument to the side of the phaco needle. It is chopped in half by pulling the chopper to the left and slightly down while moving the phaco needle, still in foot position 2, to the right and slightly up. Then the nuclear complex is rotated. The chop instrument is again brought into the golden ring (Fig. 12–2), and the nucleus is again lollipopped, scored, and chopped, with the resulting pie-shaped segment now lollipopped on the phaco tip (Fig. 12–3). The segment is then evacuated, using high vacuum and short bursts or pulse mode phaco at 2 pulses per second. The nucleus is continually rotated so that the pie-shaped segments can be scored, chopped, and removed essentially by the high vacuum assisted by short bursts or pulses of phaco. The short bursts or pulses of ultrasound energy continuously reshape the pie-shaped segments that are kept at the tip, allowing for occlusion and extraction by the vacuum. The size of the pie-shaped segments is customized to the density of the nucleus, with smaller segments for denser nuclei. Phaco in burst mode or at this low pulse rate sounds like “choochoo-choo-choo”; hence, the name of this technique. With burst mode or the low pulse rate, the nuclear material tends to stay at the tip rather than chatter as the vacuum holds between pulses. The chop instrument is used to stuff the segment into the tip or keep it down in the epinuclear shell.

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