Article Date: 3/1/2007

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Removing Retained Lens Fragments Following Cataract Surgery

A complicated case calls for a novel approach.

CARL C. AWH, MD

While cataract surgery remains one of the safest and most effective operations performed on the human body, intraoperative, vision-threatening complications can still occur. Many of these complications are expertly managed by cataract surgeons, but occasionally the services of a vitreoretinal colleague are helpful.
Every month or two, I am asked to evaluate and treat a patient with retained lens fragments following cataract surgery. Estimates indicate that 3 to 8 patients out of 1000 will experience some form of retained lens fragments following cataract surgery, and depending on the severity of the case, associated side effects range from uncomfortable inflammation and elevated intraocular pressure to cystoid macular edema and retinal detachment. Fortunately, with timely and appropriate management, the final visual outcome for the majority of patients with retained lens material is comparable to patients having a single, uncomplicated cataract surgery.



Removing retained lens fragments is usually a straightforward task, particularly in eyes in which the retained lens material consists mainly of lens cortex, epinucleus, or smaller amounts of lens nucleus. In such cases the lens material is easily removed with a 25-g vitreous cutter. This allows me to perform the surgery using the sutureless, transconjunctival Millennium TSV25 system (Bausch & Lomb [B&L], Rochester, NY).With this technique, patients remain comfortable and the absence of sutures eliminates the induced astigmatism caused by sutured sclerotomies. (Several recent studies, including one authored by Lukas Kellner,MD, Barbara Wimpissinger,MD, Ulrike Stolba, MD,Werner Brannath, PhD, and Susanne Binder,MD, of Vienna’s Rudolf Foundation Hospital, show that the 25-g vitrectomy system offers significantly improved patient comfort during the first postoperative week. The smaller surgical openings facilitate wound healing and minimize pain when compared to 20-g surgical systems.)1 However, many cases require the use of largergauge instruments, such as a 20-g fragmatome, to remove large pieces of lens nucleus. In these cases I still often use the TSV25 system, enlarging a single sclerotomy to introduce the fragmatome after first using the 25-g cutter to perform the vitrectomy and remove the softer portions of lens material.

USING 25-G TECHNOLOGY IN A 20-G SITUATION
Recently, I encountered a patient in whom the entire lens nucleus dislocated into the vitreous cavity during cataract surgery. The cataract surgeon was able to perform a careful anterior vitrectomy and insert a sulcus-fixated intraocular lens before referring the patient (Figure 1). In planning the surgery, I anticipated the need for a 20-g fragmatome but decided to begin the case using the TSV25 system with the recently-introduced adaptable vitrectomy enhancer (AVE) vitrectomy cutter from B&L (Figure 2).
I first inserted 3 transconjuctival microcannulas using the B&L TSV25 Entry Site Alignment System. Although the patient had a clear-cornea cataract wound, no sutures were needed to maintain wound integrity during cannula insertion. The smaller handpiece and stiffer cutter shaft of the AVE cutter made removal of vitreous and cortical lens material from the region of the lens capsule noticeably easier. I was able to remove vitreous with virtually no traction at the maximum cut rate of 2500 cuts per minute (approximately 41.67 Hz). The vitrectomy took no longer than with most 20-g systems.

THE NEXT STEP
After performing the vitrectomy and removing the lens cortex and epinucleus, I found myself faced with an entire, mature lens nucleus resting on the retinal surface (Figure 3). This is typically the time to remove a microcannula, enlarge the sclerotomy with a microvitreoretial blade, and turn to the 20-g fragmatome. I elected to first approach the lens with the 25-g cutter and was able to effectively engage,

manipulate, and remove the entire lens nucleus. The cutter’s optimized port geometry and cutter blade duty cycle make it possible to effectively remove materials (eg, lens material, clotted blood) (Figure 4)
Although removal of a lens nucleus with the TSV25 system and the AVE cutter may take take a bit longer than with a 20-g fragmatome, this is compensated for by the elimination of the scleral and conjunctival sutures and by more rapid postoperative improvement in visual acuity. The increased stiffness of the cutter addresses one of the more common criticisms of 25-g vitrectomy.

As ophthalmologists, we continually search for techniques and technologies that lead to improved visual outcomes for our patients. It is particularly gratifying if we can achieve this goal with improved operating room efficiency. The evolution of 25-g vitrectomy continues with a faster, stiffer, and safer cutter, allowing us to offer the benefits of the most minimally invasive form of vitrectomy surgery to more of our patients.

REFERENCE
1. Kellner L, Wimpissinger B, Stolba U, Brannath W, Binder S. 25 gauge versus 20
gauge system for pars plana vitrectomy: a prospective randomized clinical trial.
Br J Ophthalmol. 2007;91:Epub ahead of print.

Carl C. Awh, MD, is an ophthalmologist in practice with Retina-Vitreous Associates, PC, of Nashville, Tenn. Dr. Awh is a surgical consultant to Bausch & Lomb.



Retinal Physician, Issue: March 2007