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Cataract Surgery | Mar 2009

Posterior Assisted Levitation

PAL may avoid sending the patient to a vitreoretinal surgeon for an additional procedure.

In 1991, I described in a textbook on cataract surgery,1 of which I was co-author, a technique for using a cyclodialysis spatula through the pars plana to elevate a dropping piece of nucleus. A few years later, this method was popularized and named by Charles D. Kelman, MD, as posterior assisted levitation (PAL; Figure 1).

Seven years later, I described an alternative method—Viscoat levitation—in which Viscoat (4% chondroitinsolfate, 3% sodiumhyaluronate; Alcon Laboratories, Inc., Fort Worth, Texas) was applied through the pars plana to elevate the dropped nucleus in a similar way. However, the difference with this technique is that it freed up one hand for intraocular maneuvres, such as manipulating or chopping remaining pieces of nucleus with the left hand while using the phaco handpiece in the right hand. As we have discovered, pieces of nucleus do not immediately descend into the vitreous cavity through a break in the posterior capsule.

PAL and Viscoat levitation (Figure 2) are techniques designed to assist the anterior segment surgeon in completing a dropped nucleus case successfully, without the need to send the patient to a vitreoretinal surgeon for additional surgery.

WHEN TO THINK ABOUT PAL
There are often obvious signs that the capsule has ruptured, including a sudden deepening of the anterior chamber, a localized intensification of the red reflex, and a sharp reflex from the edge of the torn capsule. Often, when you have broken the posterior capsule, nuclear pieces or even most of the nucleus is still present. These pieces may eventually descend through the posterior capsular break—they may even have started to pass posteriorly by the time you have realized the capsule ruptured. Although recognizing a posterior capsular break earlier in the process is ideal, it may still be possible to stabilize the remaining nucleus and prevent it from disappearing into the vitreous cavity.

In these situations, what should you do? Use PAL.

PAL TECHNIQUE
Thankfully, the need for PAL is not common. In 30 years of performing phaco, I have probably used it only 25 times. My PAL technique is as follows:

  1. Stop irrigation but leave the phaco needle and sleeve in the eye.
  2. Remove the sideport instrument and replace it with a cannula on an ophthalmic viscosurgical device (OVD) syringe. I prefer using Viscoat to fill the anterior chamber.
  3. Remove the phaco tip and sleeve.
  4. Assess what is required to replace the nucleus in the anterior chamber (ie, Viscoat levitation or PAL). It is possible that both will be needed.
  5. If under topical anesthesia, inject 2% lidocaine under the conjunctiva. This is where the pars plana incision will be made.
  6. For Viscoat levitation, mount a 25-gauge needle on the Viscoat syringe and push it directly through the conjunctiva and sclera, approximately 3 mm behind the limbus.
  7. Start to elevate the nucleus and inject the OVD into Berger's space until the nucleus or piece of nucleus reaches the appropriate anatomical level. The OVD will support the nuclear piece.
  8. Place a Sheets glide underneath the nuclear piece to act as a pseudocapsule while the nuclear piece is removed. You may need to modify the size of the glide if a miniglide is not available. It may be necessary to carry out bimanual vitrectomy to prevent traction on the vitreous base before phaco is initiated for removal of the nuclear fragment.

 

IN THE EVENT A PIECE GETS TRAPPED
Sometimes, the nuclear piece may get trapped behind the capsule. Using Viscoat alone may not be enough to relocate the nuclear piece. In these situations, I use the following protocol:

  1. Use a microvitreoretinal blade through the pars plana to elevate the nuclear piece through the capsule.
  2. Place Viscoat under the nuclear pieces.
  3. Use microscissors, if needed, to free vitreous from the nuclear fragment to prevent traction.
  4. Again, place the Sheets glide to enable safe removal of the nuclear pieces.
  5. Keep the same phaco settings at this stage, whatever form of elevation is used.
  6. Reduce the bottle height to approximately 50 cm. Vacuum and aspiration flow rate should also be reduced; the amount will depend on the phaco needle in use.
  7. Remove the nucleus above the glide.
  8. Inject triamcinolone acetonide to check for retained vitreous. If any is present, remove it.
  9. Decide on the appropriate IOL to use, depending on the state of the anterior capsule.
  10. Breathe a sigh of relief! You have just saved your patient from having to make an unscheduled visit to the vitreoretinal surgeon.

 

Richard Packard, MD, FRCS, FRCOphth, practices at the Prince Charles Eye Unit, King Edward VII Hospital, Windsor, England. Dr. Packard states that he has no financial interest in the products or companies mentioned. He may be reached at e-mail: mail@eyequack.vossnet.co.uk.

  1. Packard R, Kinnear FC. Manual of Cataract and Intraocular Lens Surgery. Churchill Livingstone; Edinburgh; 1991:47.

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