This article is more than 5 years old. Information may no longer be current.
Surgeons describe sleeveless phaco tip-assisted levitation of dropped nucleus
The technique, coupled with an IOL scaffold and glued IOL techniques, allows a closed chamber intraocular manipulation of a dropped nucleus.
Click Here to Manage Email Alerts
Cataract surgery has advanced in the recent past with new phacoemulsification techniques, small-incision surgery, femtosecond laser application and premium foldable IOLs, all delivering toward an improved postoperative vision that translates into a happy patient. However, even with such advances in cataract surgery, one of the rare but dreaded major complications for the surgeon is posterior dislocation of the cataractous lens into the vitreous cavity.
Such mishaps can have permanent deleterious effects on both short-term and long-term visual outcomes, including intraocular inflammation, uveitis, corneal endothelial decompensation and corneal edema, secondary IOP elevation, cystoid macular edema and blurred vision, vitreous hemorrhage, retinal tears and even possible retinal detachment. The incidence of posterior lens dislocation ranges from 0.3% to 1.1%. Surgical risk factors for the complication include hard brunescent cataract, small pupil, deep-set eyes, pseudoexfoliation, traumatic cataract, posterior polar cataract and intraoperative patient movement.
Ironically, a dropped nucleus is largely a complication that has been generated by advances in modern cataract surgery. During the traditional extracapsular cataract extraction (ECCE) procedure, a dropped nucleus was largely a non-issue. This approach utilized entire lens expression via a large limbal wound, in which the increased posterior segment pressure (posterior-to-anterior pressure differential) pushed the lens anteriorly out of the limbal incision, and the lens did not drop into the posterior vitreous cavity.
Compared with the former ECCE technique, in modern-day phacoemulsification, the posterior-to-anterior pressure differential has been largely reversed due to a somewhat sealed small surgical wound and the use of fluid infusion to maintain the anterior chamber pressure. In such a setting, a dropped nucleus can be associated with weak zonules, increased anterior-to-posterior pressure gradient and intraocular surgical manipulations of the phacoemulsification procedure. The lens can sink via a posterior capsular breach into the less dense vitreous body. Surgical management of a dropped nucleus includes viscoelastic-assisted anterior floating of the nucleus, pars plana vitrectomy with or without perfluorocarbon liquid, emulsification with an ultrasonic fragmenter or removal via an extended original incision.
In this column, Drs. Agarwal and Narang describe their surgical technique of management of a dropped nucleus.
Thomas “TJ” John, MD
OSN Surgical Maneuvers Editor
Amar Agarwal
Priya Narang
Various techniques have provided new ways of managing a dropped nucleus with improved visual outcomes and fewer complications. After successful management of a dropped nucleus, IOL implantation is needed to achieve good visual rehabilitation. As far as visual output is concerned, the surgeon faces a dual challenge of managing a complication such as a dropped nucleus and simultaneously striving to achieve the expectations of a routine cataract surgery patient.
In 1999, we described a technique called FAVIT, meaning “fallen in vitreous,” for levitating a dropped nucleus. This technique has undergone several modifications by us and is currently named SPAL, for sleeveless phaco tip-assisted levitation of a dropped nucleus. SPAL, along with the application of an IOL scaffold and glued IOL techniques, allows a completely closed chamber intraocular manipulation of a dropped nucleus and IOL implantation, thereby providing all the benefits of a small-incision cataract surgery without the use of any special surgical adjuncts.
Surgical technique
Standard three-port pars plana vitrectomy incisions are framed and a thorough vitrectomy is performed to remove all the cortical matter in the pupillary plane (Figure 1) to enhance visualization, followed by a complete posterior chamber vitrectomy and removal of all vitreolenticular adhesions (Figure 2). An endoilluminator or a chandelier system can be used to improve visualization in the posterior chamber. The trocar-cannula on the dominant hand side is removed, and the incision is enlarged with the passage of a micro-vitreoretinal blade to facilitate the entry of a 20-gauge sleeveless phaco tip.
Figure 1. Three-port pars plana vitrectomy incisions are framed. Endoilluminator is introduced for better visualization. Vitrectomy is performed in the pupillary plane.
Images: Agarwal A, Narang P
Figure 2. Vitrectomy done to release all vitreolenticular adhesions.
Figure 3. Phaco tip embedded in the nucleus in the mid-vitreous cavity.
Figure 4. Nucleus is levitated and brought in to the anterior chamber.
Figure 5. A three-piece foldable IOL is injected beneath the nuclear fragments.
Figure 6. The IOL is made to rest on the surface of the iris, and an IOL scaffold procedure is performed.
Figure 7. The entire nucleus is emulsified.
Figure 8. Due to inadequate sulcus support, the glued IOL procedure is performed. Iris hooks are placed to enhance the visualization, and a haptic is externalized.
Figure 9. Both haptics are externalized.
Figure 10. Vitrectomy performed to remove small residual nuclear fragments in the vitreous cavity.
Figure 11. Scleral flaps sealed with fibrin glue. Stromal hydration is done to ensure proper wound closure. Air bubble injected is in the anterior chamber.
When the phaco tip lies close to the dropped nucleus, suction mode is initiated and the dropped nucleus is lifted from the surface of the retina with the help of a phaco tip. As the nucleus is elevated and brought into the mid-vitreous cavity (Figure 3), phaco energy mode is initiated to embed the nucleus, which is then effectively levitated, brought in to the anterior chamber and placed above the surface of the iris (Figure 4). A three-piece foldable IOL is injected beneath the nuclear fragments, and an IOL scaffold procedure is performed (Figures 5 to 7). In cases of adequate sulcus support, the same IOL can then be placed above the support of the anterior capsulorrhexis, whereas in cases of inadequate sulcus support, the glued IOL procedure can be performed to facilitate IOL fixation (Figures 8 and 9). At the end of the case, the periphery of the retina is meticulously inspected for breaks, and if any cortical matter is present, it is removed with the vitrectomy probe (Figure 10). Stromal hydration is done, and all the corneal wounds are secured (Figure 11). A 4-0 Vicryl suture is used to close the sclerotomy site, which was enlarged for introduction of the phaco needle.
In cases of very hard or dense brown cataract, we do not recommend the IOL scaffold procedure after levitation in to the anterior chamber because of concern for the corneal endothelium. In such cases, the incision can be enlarged to facilitate nucleus extraction followed by IOL implantation.
Discussion
The SPAL technique offers various advantages as to minimizing the amount of phaco energy delivered in the vitreous cavity. Levitating the dropped nucleus followed by its emulsification in the anterior chamber encompasses an ideal surgical scenario. This technique does not necessitate the use of any special surgical instrument such as a phacofragmatome or surgical adjuvant such as perfluorocarbon liquid. The patient’s safety is not compromised.
Moreover, there is no strong intravitreal fluid current or inadvertent suction of residual vitreous gel resulting from the larger port of the phaco needle as vacuum is initiated when the phaco tip is very close to the dropped nucleus. In addition, prior adequate vitrectomy ensures that the vitreous cavity is filled with fluid. SPAL, when coupled with IOL scaffold, offers a very good alternative toward proper emulsification of the nucleus, and when coupled with the glued IOL technique, it offers an ideal scenario for IOL fixation in cases of inadequate sulcus support. It simultaneously maintains all of the advantages of a small-incision closed chamber intraocular surgery, even in a complicated surgical scenario.