Chapter 13 On the afternoon of November 23, 1992, the phaco chop technique was performed for the first time during the phaco of a morgagnian cataract. Prior to this, I had been performing surgery utilizing the technique of divide and conquer. But after this eventful surgery, I had learned the true nature of the nucleus, and my technique gradually changed from divide and conquer to the phaco chop. As the mechanism of this technique resembles wood chopping, I named my new procedure “phaco chop.” One of the benefits of the phaco chop technique is the dramatic reduction of ultrasonic energy delivered to the anterior segment. When I introduced the technique to cataract surgeons, I thought it would be easy and safe for them to chop the nucleus. However, after its introduction I discovered that, because surgeons did not understand the principles of the procedure, many complications occurred. I realized that some of these complications were serious as I reviewed reports of anterior capsule tears, zonular dialysis, posterior capsule rupture, loss of the nucleus into the vitreous cavity, and endothelial cell damage. Phaco chop applies the basic principle of wood chopping. Using an ax, a wood log placed on a chopping block is cracked simply by striking it in the direction of the wood fibers. The block provides counterpressure to the movement of the ax. Phaco chop applies this principle. The crystalline lens fibers run from one equator to the opposite equator through the center of the nucleus (excluding the complex structure at the Y suture). I discovered that it could be cracked in the direction of lens fibers. Therefore, in the phaco chop technique, the phaco chopper is the ax and the phaco tip is the chopping block. When chopping wood, if the log is not held correctly on the chopping block, it will fall from the chopping block. It might even jump into the air and upon impacting something in the surrounding environment cause an injury. In a similar manner, if the two instruments necessary for the phaco chop procedure are not used properly, such that one stabilizes the nucleus and the other chops, the nucleus is uncontrolled and complications ensue. In an effort to perform phaco chop in cases of a hard nucleus and/or small pupil, I have modified the procedure. This procedure is named “karate chop.” In the phaco chop technique, the chopper is placed at the hydrodelineation line and the direction of cracking of the nucleus is from the equator toward the center. In the karate phaco chop technique the direction advances from the anterior pole to the posterior. Therefore, in karate phaco chop, it is not necessary to place the phaco chopper under the iris or anterior capsule. Thus, in cases of a small pupil or a large nucleus, or small CCC, the chopper can be placed where it can be seen, making the procedure safer. The karate phaco chop is effective for the hard nucleus, grade 3 or higher. When the ultrasound (US) tip is driven into the nucleus, white smoke, or emulsate production, is the sign that the karate phaco chop is effective. To perform this technique it is important to drive the US tip deeper into the nucleus than required in the usual phaco chop technique. Additionally, more holding power is necessary. The vacuum must be increased to accomplish this. The chopper is stabbed into the nucleus from above and very close to the US tip. It is driven to the same depth of the phaco tip while the two instruments are separated, side to side, to cleave the nucleus. Upon completion of the first chop, the nucleus is rotated and divided into small pieces with repetition of the same procedure. Similar to other techniques of phaco, there are two major categories of complications: (1) those that are visible, such as damage to the anterior capsule, including tears and dialysis, and damage to the posterior capsule, including tears, vitreous loss, and lost nuclear and cortical fragments and nucleus (Table 13–1); and (2) damage that cannot be immediately visualized, such as endothelial cell damage and iris trauma with resultant damage to the blood–aqueous barrier. During the procedure the phaco chopper can tear the anterior capsule. This is most common in the early phases of the procedure, as the surgeon may have to pass the chopper under the anterior capsular edge to engage the nucleus. If the surgeon loses the view of the anterior capsular edge, the chopper may inadvertently be placed over, rather than under, the anterior capsule. The downward pressure of the chopper can tear the edge of the anterior capsule or create a zonular dialysis (Fig. 13–1
PHACO CHOP
MECHANISM OF THE PHACO CHOP TECHNIQUE
KARATE CHOP—AN ALTERNATIVE TECHNIQUE
MAJOR COMPLICATIONS OF PHACO CHOP
MANAGEMENT OF COMPLICATIONS
Anterior Capsule
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