QUADRANT MOBILIZATION AND

EMULSIFICATION/REMOVAL

There are three basic methods for quadrant management and removal that have been described1,6,7 and multiple variations of each. The fluidic settings, that is, the vacuum and aspiration flow rate, should be readjusted for this phase of the procedure. Because vacuum is used to hold the quadrant to the ultrasound tip, the vacuum setting should be increased, or inefficient emulsification of the quadrants will occur.

Difficulty with quadrant management, most commonly in retrieving the first one, is usually due to interlocked posterior plate edges, short troughs with interlocked peripheral edges, or incomplete splitting of the posterior plate itself. Each split should be examined to ensure that the peripheral cortex and the posterior plate are completely cracked, producing separate quadrants. If the posterior plate is completely cracked, yet difficulty in mobilizing the initial quadrant is still encountered, re-spreading the quadrants and then anteriorly displacing one of the quadrant edges as the quadrants are allowed to return together will unlock the lamellae holding quadrants together. This maneuver places one edge of the split posterior plate into the previously created trough space. This typically facilitates quadrant centralization. Once the first quadrant has been removed, the additional space created within the capsular bag allows for trouble-free manipulation of the remaining quadrants.

A small capsulorrhexis will act to hold the quadrant in place, thus making it more difficult to mobilize using the vacuum of the ultrasound tip. In this circumstance, the first quadrant is most easily managed by using the second instrument to lift its apex anteriorly so that the ultrasound tip can be embedded into the apex of the exposed posterior plate and, using aspiration but no ultrasound, the quadrant can be pulled centrally to be emulsified. If the pupil is small and prevents visualization of the quadrant, the iris may be gently retracted at the pupil margin by a

second instrument, thus giving a better view before the aspiration of the ultrasound tip is engaged.

If it appears impossible to mobilize a quadrant, the phaco tip can be withdrawn and viscoelastic can be utilized to lift the quadrant to the level of the pupillary plane for emulsification.

Use of the angled Kelman ultrasound tip may be an advantage during the trough sculpting phase; however, during the quadrant emulsification phase the posteriorly angled tip has the potential for hitting the posterior capsule. This tip should therefore be rotated 90 degrees so that the angled tip is in the horizontal rather than vertical position. The irrigation sleeve may need to be rotated also. The orientation of the irrigation holes in the irrigation sleeve should be in the same plane as the tip angle, so that when the tip is rotated during the quadrant removal process the flow through them is in the plane of the iris rather than directed at the corneal endothelium.

REFERENCES

1.Shepherd JR. In situ fracture. J Cataract Refract Surg 1990;16:436–440.

2.Gimbel HV. Divide and conquer nucleofractis phacoemulsification: development and variations. J Cataract Refract Surg 1991;17:281–291.

3.Fine IH, Maloney WF, Dillman DM. Crack and flip emulsification technique. J Cataract Refract Surg 1993; 19:797–802.

4.Gimbel HV, Neuhann T. Development, advantages, and methods of the continuous circular capsulorhexis technique. J Cataract Refract Surg 1990;16:31–37.

5.Fine IH. The chip and flip phacoemulsification technique. J Cataract Refract Surg 1991;17:366–371.

6.Davison JA. Hybrid nuclear dissection technique for capsular bag phacoemulsification. J Cataract Refract Surg 1990;16:441–450.

7.Johnson SH. Split and the left: nuclear quadrant management for phacoemulsification. J Cataract Refract Surg 1993;19:420–424. [Published erratum appears in J Cataract Refract Surg 1993;19:567–569.]

TECHNIQUE OVERVIEW

The stop and chop phacoemulsification technique consists of several simple steps and is an efficient method for emulsifying the nucleus. Thorough hydrodissection is performed to loosen the nucleus within the bag. Sculpting is performed to prepare space in the middle of the cataract in which the nucleus can be manipulated later on in the procedure. The sculpting should produce a trench in soft and medium-density cataracts and a large crater in dense cataracts. The posterior plate is split, producing two nucleus halves that are free-floating and capable of being manipulated into the space prepared by creating the trench or crater.

At this point nucleus preparation stops and the emphasis shifts to the chop. The nucleus is rotated 90 degrees and the phaco tip is buried deeply into the hemi-nucleus about one-third of the way from right to left. The chopper is placed in the periphery of the nucleus and pulled toward the phaco tip. As the instruments reach each other they are separated, effectively chopping off the nucleus segment. That segment is already impaled on the phaco tip and can be emulsified without further manipulation. This step is repeated around the rest of the nucleus, chopping off segments and emulsifying them.

PROBLEMS DURING THE PROCEDURE

DAMAGING THE SIDES OF THE

CORNEAL INCISION

The temporal corneal incision should be as square as possible. If the incision is between 2.5 and 3 mm wide, it should also be about 2 mm in length. There

are many excellent keratomes designed to make an incision of this proportion. The keratome is designed to be moved in a straight line from external to internal. If the blade is wiggled slightly to the left or to the right during incision construction, the sides of the incision can be nipped and “winged.” When this happens, the central length of the incision could still be the full 2 mm, but the effective side length might be only 1 mm. This is an inadequate incision and is a source of fluid leakage and unsatisfactory incision closure. Stromal hydration could be enough to seal this part of the incision, but sometimes a suture is required to make it secure.

CONTROLLING THE CAPSULORRHEXIS