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Good outcomes possible in patients who experience dropped nucleus, vitreous loss
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In the United States, statistics of vitrectomy pack usage vs. phaco pack usage by American cataract surgeons suggest that the incidence of vitreous loss is close to 5% in the U.S., representing 160,000 cases per year. Vitreous loss is the most common intraoperative complication the cataract surgeon must manage.
 Richard L. Lindstrom |
I was once asked to review the outcomes of a multicenter chain of ASCs, and the vitreous loss rate of several hundred surgeons using exactly the same phaco equipment, the same microscope, the same surgical assistants, etc., ranged from 0.6% to 20.4%. I was asked: “What is acceptable, and what do we do with surgeons outside the acceptable range?” I said 5% or less was the target and anything over 10% was unacceptable. I recommended required proctoring for the surgeons with vitreous loss rates over 10% and the opportunity for proctoring for those over 5%. This process resulted in significant improvement in outcomes.
The primary goal is avoidance. Once the capsule is gone, a layer of dispersive viscoelastic, as taught by Dr. Dick Mackool, might well help keep the nucleus anterior, another potential advantage of this technique. But most important, as shown recently by Bobby Osher, MD, and his son Jamie in an award-winning video, is the unexpected finding that in regards to preventing nucleus loss posterior, the vitreous is our best friend. Once the capsule is broken, turn off the ultrasound, hold the phaco steady with infusion on, do not disturb the vitreous face, and the nucleus will stay in the anterior segment.
Take your time
Leave the vitreous alone until the nucleus is out, and you will not lose the nucleus posterior. Take out the second instrument, hold the phaco tip steady with irrigation only, ask for an OVD (preferably dispersive, but take what is on the table) and pass the cannula through the side port and inject viscoelastic under the nucleus, not over it. Exchange balanced salt solution for viscoelastic and then withdraw the phaco tip. Now there is no hurry. Do a careful evaluation, including retraction of the iris with a manipulator, so the exact situation is fully understood, and get the tools necessary to deal with the situation in place.
In many cases, it is possible to subluxate the nucleus completely into the anterior chamber, place dispersive OVD under it and complete the phacoemulsification, supporting the nucleus toward the angle over the iris. A Sheet’s glide can also be helpful in select cases, but must be cut to the proper size for small incisions, and an irrigating vectis or lens loop is great for cases in which opening the wound and converting to a planned extracapsular cataract extraction is selected. If the hyaloid face is intact, clean the cortex using a low-flow or dry technique and implant a lens, usually a posterior chamber lens with optic capture.
Sometimes the capsule comes completely free, necessitating total removal with forceps. It is helpful to know how to iris fixate and scleral fixate a posterior chamber lens, but I do not hesitate to implant a modern anterior chamber lens. They work great and look good in most cases for decades.
Removing the vitreous
If vitreous prolapses into the anterior chamber, careful vitrectomy to eliminate all vitreous from the anterior segment is critical. It is best done bimanually using a mechanical cutter with irrigation separated from the cutter. Small incisions, low flow, low vacuum and a high cut rate make it safer. It can be done well through the limbus, but make a new incision for the cutter opposite the paracentesis so it is more watertight. Turn the cutter port posterior and go below the iris plane to pull the vitreous out of the anterior segment. Always face the cutter port away from the iris so you do not cut it.
This can work and is in the comfort zone for most surgeons, but making the second incision for the cutter through the pars plana makes it all easier. Take a Merocel sponge with topical anesthetic and hold it over the conjunctiva for 15 to 20 seconds. Make a small cut in the conjunctiva parallel to the limbus with Wescott scissors. Cauterize with a wet field. Firm up the eye with viscoelastic, and pass a vitrectomy blade through the sclera and pars plana 3 mm posterior to the limbus. Push the blade in until you can see it in the pupil, and pull it straight back out. Put infusion in the paracentesis sideport with one hand, and then the vitrector through the pars plana incision with the other. Now it is easy, with infusion anterior and the vitreous cutter posterior to the plane of the capsule to pull the vitreous out of the anterior chamber.
When finished, take out the vitrector first, the infusion second and suture the pars plana wound closed. This same approach can also be used to do visco-elevation of a nucleus that has subluxated slightly posterior, and epinucleus and cortex are easily removed with the vitrector.
If the nucleus or nuclear fragment are posterior enough that I cannot visualize them well without a contact lens, I leave them for the vitreoretinal surgeon. The vitreoretinal surgeons I work with support performing an anterior vitrectomy, cleaning cortex compulsively and placing a well-fixated IOL. Help your vitreoretinal surgeon by placing a stable IOL and suture the wound as well.
I inject steroid, either subconjunctival or intravitreal, and treat all eyes with vitreous loss more aggressively and longer with NSAIDs and topical steroids, at least 8 to 12 weeks. Get a retina consult as soon as possible if there is retained lens material. If well managed, these patients can and usually do have excellent outcomes.