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Novel method manages dropped nucleus with perfluorocarbon liquid
The technique utilizes small-gauge, three-port pars plana vitrectomy and perfluorocarbon liquid to fill the vitreous cavity.
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One of the downsides to modern-day cataract surgery is the rare but potentially serious vision-threatening complication of dropping the cataractous nucleus into the vitreous cavity. Such a significant complication can occur even in the most experienced hands. The best option for an anterior segment surgeon is to close the wound, refer the patient to a vitreoretinal surgeon and resist the temptation of going after the dropped nucleus. Predisposing factors in phacoemulsification-associated dropped nucleus include hard cataract, posterior polar cataract, previously vitrectomized eyes and high myopia.
One recent study reported the most frequent cause for malpractice claims in England from 1995 to 2008 was negligent surgery including posterior capsular tear and dropped nucleus. Hence, the medicolegal implications of such an intraoperative complication need to be addressed, and preoperative discussion with the patient is important when it comes to damage control.
Once the nucleus is dropped posteriorly, this can lead to inflammation, macular edema, rise in IOP and possible retinal detachment. Hence, early surgical intervention is essential to optimize the postoperative outcome. Various approaches have been described in the literature to address this complication. In this column, Drs. Prasad and Hussain describe their technique of using perfluorocarbon liquid after pars plana vitrectomy, combined with anterior segment clear cornea phacoemulsification and IOL placement, in the surgical management of a dropped nucleus.
Thomas John, MD
OSN Surgical Maneuvers Editor
Most conditions requiring pars plana vitrectomy (PPV) are now amenable to small-gauge sutureless surgery, leading to increased postoperative comfort, quicker healing and reduced postoperative inflammation. One of the few remaining indications for a 20-gauge vitrectomy remains a dropped nucleus with dense nuclear material in the posterior segment as a result of complicated cataract surgery. The common surgical approach is through a PPV with fragmentation of the nuclear material within the vitreous cavity and subsequent insertion of a suitable IOL. All currently available fragmatomes are 20 gauge; therefore, this procedure requires larger-gauge surgery and carries risk of retinal damage with the use of ultrasound energy in the posterior segment of the eye. If small-gauge surgery is used, one port has to be opened for the fragmatome, which can then cause fluidic imbalance during nucleus removal, resulting in intraoperative hypotony, which is not desirable, and usually suture closure of the 20-gauge port.
Our technique for the management of displaced nuclear fragments into the posterior segment uses a novel approach. We use a 25-gauge or 23-gauge three-port PPV, with perfluorocarbon liquid used to fill the vitreous cavity, floating the nucleus forward. Conventional phacoemulsification through clear corneal incisions is then performed, behind the remaining anterior capsule or in the iris plane, following which the perfluorocarbon liquid is removed and a peripheral retinal check is performed. A suitable IOL is then inserted through the corneal incision. The entire procedure is faster, well controlled and preserves the advantages of a completely sutureless approach.
Surgical technique
A three-port, sutureless, transconjunctival small-gauge PPV is performed (Figures 1 and 2) with induction of a posterior vitreous detachment. A near total vitrectomy including a vitreous base shave is done by indentation, so that the rest of the procedure is done in a vitreous-free environment, eliminating the risk of vitreoretinal traction. Any soft lens matter adherent to the capsular bag remnants are aspirated and peeled away to improve posterior segment visualization. The vitreous cutter removes soft lens matter in the vitreous cavity. Perfluorocarbon liquid is introduced into the posterior segment, and dense nuclear fragments are floated to a plane at or behind the anterior capsule. Two clear corneal incisions are created, and phacoemulsification is performed with the lens stabilized on the bed of perfluorocarbon liquid either behind the anterior capsule or at the iris plane. It is important to keep fluidics in mind to avoid the nucleus being repulsed, as there is no capsular bag to support it. A very low duty cycle for ultrasound energy and technology such as OZil (Alcon), if available on the surgical platform, facilitate this step. Phacoemulsification (Figures 3 and 4) can be performed with either a coaxial or biaxial approach, depending on surgeon preference.
Figure 1. Introduction of perfluorocarbon liquid into the vitreous cavity to float the nucleus up.
Figure 2. Nucleus elevated plane just behind the anterior capsule, which is present in this case.
Images: Prasad S, Hussain A
Figure 3. Phacoemulsification of nucleus is started.
Figure 4. Completion of phacoemulsification.
Source:
Figure 5. Removal of perfluorocarbon liquid.
Figure 6. Placement of IOL in sulcus.
The vitreous cavity is subsequently re-accessed to remove the perfluorocarbon liquid (Figure 5), and a complete check of the peripheral retina is performed. Any small fragments of nucleus that may have fallen back again can be removed with the vitrectomy cutter at this stage. A suitable IOL is inserted (Figure 6) into the sulcus, if sufficient capsular support is present; in the absence of capsular support, scleral fixation or an anterior chamber IOL can be used as deemed necessary.
Discussion
Although an uncommon occurrence in routine cataract surgery, the dropped nucleus represents a sight-threatening complication of phacoemulsification. Nuclear fragments left within the vitreous cavity can induce a significant phacoanaphylactic response, leading to postoperative uveitis. Therefore, prompt and complete removal of the nucleus is important to give the patient the best chance of visual recovery. Previous hazardous methods to manage this problem included trapping the lens anteriorly with needles, cryoextraction of the lens in an air-filled eye, and the use of sodium hyaluronate in manipulating the nucleus. Perfluorocarbon liquids have been established in their role of the surgical management of retinal conditions, and their physical properties and nontoxic nature make for an ideal medium to be used in this setting. Combining this with the small incision and more stable fluidic environment of a phacoemulsification procedure offers a viable option in the management of this problem.
We propose our sutureless technique for the management of the dropped nucleus during cataract surgery, which could offer a better safety profile, particularly in the absence of a commercially available 23- or 25-gauge fragmatome. Shapiro et al use perfluorocarbon to retrieve the lens from the vitreous cavity; however, they deliver the lens through a standard extracapsular corneal incision. Our method maintains the advantages of small self-sealing corneal incisions for phacoemulsification surgery combined with small-gauge transconjunctival sutureless pars plana incision for posterior vitrectomy. Until a 23- or 25-gauge fragmenting device becomes commercially available, the technique described here holds promise in the management of this complication, allowing a fast, controlled and safe nucleus removal. In fact, even if small-gauge fragmatomes become available, it may remain preferable to use our technique because the phacoemulsification part of the procedure is likely to remain more efficient through an anterior approach.