Management of Dropped Lens Fragments

They can be removed either intraoperatively or by vitrectomy.

By Sina J. Sabet, MD, FACS

How to ruin a cataract surgeon's day? Having to deal with vitreous is usually enough. Add a dropped lens to the mix and you can guarantee you will not be dealing with a happy surgeon.

First Signs of Trouble

There we are, comfortably in our routine of cataract surgery when we start to get the feeling that something is terribly amiss. The anterior chamber begins to deepen, the lens fragments become harder to rotate and follow with the phaco tip, and we may ultimately start to see lens fragments or the whole lens start to wobble and fall out of view into the deep vitreous cavity.

How quickly and effectively we react to such a scenario will make the difference between completing the case successfully or exposing the patient to numerous postoperative complications, including chronic pain and inflammation, prolonged cystoid macular edema, retinal tears and detachments, glaucoma and/or pseudophakic bullous keratopathy.

In this article I will attempt to address some of the techniques of dealing with this scenario, with emphasis on the use of an instrument I have created to help facilitate its management in select cases.

Optimal management is complicated by several factors. One is that this is (fortunately) a relatively rare complication. But this means that most surgeons, especially beginning surgeons, do not have significant experience in dealing with it, and so much anxiety is created. The combination of the anxiety and inexperience often lead to rash and dangerous maneuvers, setting the patient up for unnecessary complications. The other is that the optimal management of this complication remains controversial, even among experienced surgeons.

The Vitrectomy Option — How Soon?

Vitreoretinal surgeons are almost unanimous in their recommendation that any descending fragments be allowed to fall, and aggressive intraoperative attempts at retrieval be minimized. If vitrectomy performed by a retinal specialist is the choice, a study presented at this year's ARVO meeting and conducted by the Duke University Eye Center provides some insight into the best timing for this procedure.

P. Mruthyunjaya et al. concluded that retained lens fragments resulting from a cataract surgery complication are best removed sooner rather than later.

In a retrospective review of 73 patients referred to the Duke Eye Center for posterior capsule rupture and retained lens fragments, patients who underwent a pars plana vitrectomy (PPV) within seven days after cataract surgery typically had better final visual acuity than those patients who had PPV at eight to 30 days.

The researchers found no other significant differences between these interval groups in outcomes or complications. They also cautioned that patients referred to a retina specialist with retained lens fragments may present with significant morbidity, including endophthalmitis, retinal de tachment, corneal edema and elevated IOP.

If this option is your choice, I recommend that the vitrectomy be performed within one or two days following the primary cataract surgery. At that point, the ball is in the retina specialist's court.

Intraoperative Methods

However, anterior segment surgeons sometimes remain divided on optimal management. Many will show numerous videos of successfully managing such descending fragments with aggressive measures. The temptation to intervene while there are still things you can do is quite strong in the operating room.

Charles Kelman, the late founder of modern phacoemulsification surgery, is among those who suggested a technique for anterior segment surgeons to manage this complication during the primary surgery¹. He called it the PAL technique, standing for Posterior Assisted Levitation. In this technique, the surgeon places an instrument behind the dropping lens fragments, often through the pars plana. This will stabilize the fragments, allow the surgeon to bring them forward into the anterior chamber, and allow phacoemulsification to continue.

However, this technique has suffered from many criticisms. One is that the instrument that is used to stabilize the fragments, often a cyclodialysis spatula, does not stabilize the fragments very well at all. Even if the lens is still in one piece, it will wobble and tilt over such a narrow support, making continued phacoemulsification quite challenging. The other is that phacoemulsification is often done in the presence of vitreous. Despite occasional claims to the contrary, the phacoemulsification tip does not cut through vitreous, and continued phacoemulsification in the presence of vitreous can place significant and dangerous levels of traction on the vitreous and retina.

The Lenticular Safety Net

This is how the idea of a lenticular safety net (Rhein Medical) came about (Figure 1). The idea was to devise an instrument that could be used for posterior-assisted levitation, but that allowed better support of nuclear fragments, as well as allowing a limited vitrectomy to proceed in which the lens fragments were stabilized. More stable support would mean that the surgeon could then take his/her time to better clean up the vitreous around the lens fragments and facilitate safer removal of the fragments.

Figure 1. The safety net in profile, unopened.

The net in open position is shown in profile and superior view in Figure 2. As can be seen, the bore of the instrument is 23-gauge, and can be introduced through either a small paracentesis or a pars plana incision. Once inside, a sliding button will open the net, which is a series of four small wires that come out and expand from the bore. The wires have a curve to support the natural curve of the posterior aspect of the lens. The wires are also turned up at the end, to prevent any inadvertent damage to intraocular structures as the net is being opened, as well as to provide some traction against slippage of lens fragments. This can be used to support either a single lens fragment or multiple fragments.

Figure 2. The safety net in profile and superior view, net in open position.

Once the lens is supported in this way, vitrectomy can be done to clean any vitreous that may be entrapping the fragment. Of course, one hand of the surgeon will be occupied with holding the net, therefore two-port vitrectomy cannot be done. However, a single-port vitrectomy, introduced through the main incision, is usually adequate to allow a limited anterior vitrectomy. Once the vitreous is cleaned, a dispersive viscoelastic can be placed to push back the remaining vitreous. The lens fragments can be brought forwards into the anterior chamber, and phacoemulsification can be completed. Frequent refilling with dispersive viscoelastic may be required.

Some surgeons who have used this instrument have preferred a pars plana introduction, finding it easier and less awkward. However, this requires time to prepare. This can be done if the dropping fragments are stabilized in viscoelastic. There is also some interest in modifying the bore of the instrument to be more of a needle, allowing its introduction directly through the conjunctiva, much the same way as retina specialists now introduce their 23-gauge vitrectors. This idea may be incorporated in future designs.

In summary, the Safety Net offers a modification of the technique of posterior-assisted levitation, and may offer another tool in the toolbox of the anterior segment surgeon for approaching this rare but dreaded complication of cataract surgery. OM

Reference

1. Kelman CD. Posterior capsule rupture: PAL technique. Video J of Cataract and Refract Surg. 1996; 12: No. 2