Thoughts about the cortex

This column is one in an invited series by Dr. Osher. The series highlights techniques that may be helpful in particular to young practitioners.

Once the nucleus has been emulsified, it is not uncommon to hear an audible sigh of relief as the surgeon prepares to remove the cortex. This is ironic because a capsular tear or a zonular dialysis can quickly occur if the surgeon lets down their guard. Certainly switching the irrigation/aspiration (I/A) tip from metal to silicone has reduced complications. This column will review some thoughts about cortical removal.

It is essential to grasp the cortex at its most anterior and proximal location. One should avoid allowing the I/A tip to engage the cortical floor unless he or she enjoys dealing with a residual stubborn, stringy cortex. As the vacuum increases, the surgeon may shimmy the tip as the cortex begins to separate from the anterior capsule. It is dangerous to allow the vacuum to build to a high level, while the tip is still within the confines of the capsular bag. As the vacuum is building, the tip can be lowered posteriorly to expedite the cortex stripping from the capsule. As the cortex begins to strip, the hole should be rotated away from the posterior capsule as the tip continues to move centrally beyond the edge of the capsulorhexis to avoid aspirating the posterior or anterior capsule, which could result in a posterior capsular tear or zonular damage, respectively.

As mentioned in an earlier column, it is a big advantage to remove the subincisional cortex first rather than going after the easy and seductive cortex opposite the incision. The subincisional cortex should be engaged just at the edge of the anterior capsule, which depends on the configuration of the tip. The remainder of the cortex is holding the capsular bag open, analogous to a shoe tree. By contrast, when the surgeon initiates cortex removal across from the incision, leaving the subincisional location for last, the capsular bag could be closed, making subincisional cortical removal even more difficult.

If the subincisional cortex is stubborn or the cortical fibers are peripheral to the edge of the anterior capsule, removal may be challenging. One can try to deepen the chamber to allow easier entry into the bag, but making the I/A tip more vertical can cause excessive bending of the cornea, compromising visualization. An excellent technique I have advocated for decades is to inflate the capsular bag with a cohesive ophthalmic viscosurgical device (OVD) (I prefer regular Healon), then to use a 27-gauge reverse J cannula on a 3-mL syringe filled with about 1 cc of a balanced salt solution. I have designed this cannula (B&L E6312 Crestpoint MMP243) with an angle that allows the instrument to pass through the uphill corneal tunnel, descend through the pupil, and then reach the subincisional cortex. This manual technique is very efficient when the surgeon occludes the cannula with the anterior proximal cortex and applies vacuum followed by a push–pull manual maneuver (Video 1, available at https://links.lww.com/JRS/A779).

Sometimes it is difficult, especially with a smaller pupil, to be certain that the peripheral cortex has been completely removed. One excellent clue is the presence of subtle microstriations on the posterior capsule. These indicate that there is still a peripheral cortex present. Entering the bag with the hole toward the anterior capsule and “fishing” with low vacuum will engage the residual cortex, which can then be stripped as more vacuum is applied. Other situations may challenge the surgeon, for example, when the cortex is actually a solid plate or when white corticocapsular adhesions are present as described by Vasavada et al.1 Rather than applying unnecessary force to the cortex, which seems “stuck,” viscodissection works very well.2 The cohesive OVD is injected just under the anterior capsule, acting to detach and peel the white corticocapsular adhesions off the anterior, equatorial, and posterior capsule.

Finally, the surgeon should exercise caution when going after the peripheral cortex when Trypan blue has been used to stain the anterior capsule. Because the dye can make the anterior capsule more brittle, I have seen it split when stretched by the I/A tip during routine cortical removal.

Aspirating the cortex remains one of the most satisfying steps in cataract surgery. Although usually straightforward, the surgeon should remain highly attentive and sharply focused on every step from the beginning to the very end of the operation (Figure 1).

F1Figure 1.:

Cannula designed for manual subincisional cortex removal.

1. Vasavada AR, Goyal D, Shastri L, Singh R. Corticocapsular adhesions and their effect during cataract surgery. J Cataract Refract Surg 2003;29:309–314. 2. Mackool RJ, Nicolich S, Mackool R Jr. Effect of viscodissection on posterior capsule rupture during phacoemulsification. J Cataract Refract Surg 2007;33:553

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