Deep wedge removal phacofracture requires little manipulation or rotation

This approach is a safe alternative to chopping techniques and allows easy cracking of the nucleus into three segments.

A major concern with current chopping techniques is that the bulk of the nucleus in the early stages of the procedure is excessive for the limits of stress to the capsule. If a posterior or anterior radial tear occurs at this stage, then the procedure becomes hazardous.

We present a technique that utilizes safe debulking of a central wedge-shaped core of the nucleus before nucleus manipulation or rotation. Firm to mature cataracts can be managed safely by the central removal of the wedge of nucleus. This approach yields much needed room for safer nucleus manipulation and allows easy cracking of the nucleus into three segments without any significant manipulation or rotation. It could be considered a merging of crater chop, divide and conquer, but it is unique in that three cracks can easily be accomplished without rotation or manipulation.

Surgical technique and methods

The standard approach to sutureless phaco is employed, whereby a temporal, clear corneal incision of 2.75 mm is used. Intracameral preservative-free 1% xylocaine is used. A soft shell technique of chondroitin sulfate dispersive viscoelastic followed by sodium hyaluronate cohesive viscoelastic is used to deepen the anterior chamber. A bent 25-gauge 5/8-inch needle is used to perform a circular capsulorrhexis. Hydrodissection is gently carried out with a Chang cannula, and hydrodelineation of the nucleus is also attempted at this time. The nucleus is not rotated.

Deep wedge removal phaco is accomplished by first removing the anterior layer of the cortical material. The sculpting is carried out in a V-shaped manner with the phaco pivoting at the clear corneal incision. These two deep grooves are made in a V-shaped pattern. These deep grooves are made defining the superior and inferior borders of the wedge, allowing easy judgment of the depth of the wedge. The central material is removed to complete the removal of the wedge.

Phacoemulsification is carried out completely within the capsular bag, staying well away from the cornea to remove a deep, central wedge of nucleus of 4 × 4 × 4 mm, comprising an equilateral triangle 3.5 mm deep. This geometric shape of removed material comprises a volume of 24.22 mm³. This approach has greatly reduced the bulk of the firm nucleus in that 69% of the nucleus is removed, ie, (24.22 mm³/35 mm³) × 100% = 69%. The resulting wedge-shaped cavity then exposes three points of weakness at each corner of the wedge-shaped cavity for easy cracking without rotation.

The Drysdale nucleus manipulator is used to crack remaining nuclear material at each corner of the triangle. This instrument has a broad, flat paddle design with dull edges, which maximizes safety and yet effectively cuts into nuclear material held by the phaco tip. These cracks are made fairly easily and quickly.

We have divided the nucleus into three segments, which are then easily rotated into the central empty space for phacoemulsification posterior to the iris plane for maximized corneal safety. Short bursts of phaco and vacuum grip the first, which is rotated into the space that has been created by removal of the deep wedge. Each remaining segment is rotated into the empty space centrally for careful removal. Hardened segments can be chopped or cut into smaller segments if required.

The epinucleus is removed by standard techniques of irrigation and aspiration. A bent 25-gauge needle is preferred because it allows continued ease of use as the incision size continues to get smaller. The irrigation and aspiration, as well as IOL, are placed, completing the procedure.

Discussion

Based on analysis of lens anatomy, the ideal size of the wedge is a 4 mm equilateral triangular wedge, 3.5 mm deep. Consider that the diameter of the average nucleus is 8.1 mm, and then going just as deep as possible allows the nucleus disassembly to take place efficiently with minimal phaco power, well away from the cornea.

Removal of this triangular, pie-shaped wedge of nucleus of these dimensions (Figure 1) creates three points of weakness that allow easy fracturing of the nucleus at these points (Figure 2). It is as if it is following the natural plane created by the Y-suture configuration present in the development of the lens. The nucleus has now easily been divided into three segments because the bulk of the central nuclear material has been removed. The removal of the remaining three segments, as well as dividing the three remaining segments into smaller segments, becomes much easier.

We are using a Drysdale nucleus manipulator with a broad paddle design and the phaco tip to create the fractures. The first segment is then removed and rotates up into the center where there is room for safe phacoemulsification, made possible by the deep wedge removal. The second segment, usually to the surgeon’s left, is rotated into this open space (Figure 3) and is removed, followed by the third segment. If the nuclear material is firm, it can be chopped or fractured further using the Drysdale nucleus manipulator, which is able to cut somewhat like a butter knife because it has a smooth, thin but dull edge (Figure 4).

Advantages

The advantage of this type of approach is improved safety. There is less zonular stress because there is not an initial rotation with the bulk of the cataract present. Cracking is made easier with the use of the small triangular wedge approach and is effective for soft nuclear material. There is less manipulation and rotation of a bulky nucleus if hydrodissection is incomplete. Less phaco power is used, so there is less exposure of the endothelium.

The Drysdale nucleus manipulator with the broad, dull paddle design allows easy manipulation, rotation and gentle cutting or fracturing of the nucleus and seems to be less threatening to the posterior capsule should post-occlusion surge occur. Phacoemulsification is carried out in the center, avoiding the iris and capsule edges while the phaco vacuum, following short bursts of power, continues to grip the segment. The Drysdale cuts down toward the phaco tip and then pushes horizontally enough to further fracture these larger segments into even smaller segments. Creating a short groove at the three corners of the triangle before fracturing provides a site for the Drysdale and phaco tip to accomplish the cracking easily.

Sometimes, chopping is the only way to remove a mature, hardened nucleus. This approach, however, is safe for most cases and ideal as a starting point for beginning surgeons.

References:

• Chang DF. Phaco Chop: Mastering Techniques, Optimizing Technology, and Avoiding Complications. Thorofare, NJ. SLACK Incorporated; 2004
• Hermans E, Dubbelman M, van der Heijde R, Heethaar R. The shape of the human lens nucleus with accommodation. J Vis. 2007;7(10):16.1-10.
• Taylor VL, al-Ghoul KJ, Lane CW, Davis VA, Kuszak JR, Costello MJ. Morphology of the normal human lens. Invest Ophthalmol Vis Sci. 1996;37;1396-1410.

• Norman F. Woodlief, MD, FACS, and Justin M. Woodlief can be reached at 461 Cotton Gin Road, Montgomery AL 36117; 334-323-3610; e-mail: nwoodlief@eyehealthpartners.com.