OSLI Retina

March/April 2013

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■ T E C H N I Q U E ■ Vitreous Pillow for Sustained-Release Intravitreous Drug Delivery Implants Kapil G. Kapoor, MD; Ryan W. Shultz, MD; Raymond Iezzi, MD INTRODUCTION BACKGROUND AND OBJECTIVE: Intravitreous drug delivery systems are injected or surgically implanted for sustained release of drugs to the posterior segment for conditions such as vein occlusions and diabetic macular edema. Since these devices rely upon the vitreous body for support, concerns regarding their migration and prolonged direct retinal contact have limited their use in vitrectomized eyes. PATIENTS AND METHODS: Three patients with persistent macular edema received dexamethasone intravitreal implantation following vitrectomy employing the authors' novel technique for embedding the system in a residual inferior vitreous skirt that serves as a pillow on which the implant rests after pars plana vitrectomy. RESULTS: At minimum 6-month follow-up, all patients had improved visual acuity and improved central retinal thickness on optical coherence tomography, were without complaints of floaters or migration of the implant, and were without complications. The implant consistently remained embedded in the inferior vitreous skirt. CONCLUSION: The technique may mitigate concerns regarding implant migration and direct retina contact. [Ophthalmic Surg Lasers Imaging Retina. 2013;44:181-182] Intravitreous sustained-release implants have been used increasingly but have had limited use in vitrectomized and aphakic eyes. In vitrectomized eyes, the absence of vitreous gel in which to embed the implant allows it to float freely throughout the vitreous cavity. This free floating of the implant in the vitreous cavity is cause for concern, having at least theoretic potential for mechanical foveal trauma. Patients with vitrectomized eyes confirm these concerns by reporting a higher incidence of floaters, and clinicians suggest they may experience a higher incidence of hypotony.2 Migration of intravitreous drug implants to the anterior chamber has been reported in eyes without an intact anterior hyaloid face, and corneal decompensation necessitating corneal transplant has been described.3 In aphakic vitrectomized eyes, wandering intravitreous drug implants have been reported to flow freely with change in posture between the vitreous cavity and the anterior chamber.4 In addition to migration, there are concerns with the implant being in long-term contact with the retina itself. These implants can embed into the retina and incite proliferative vitreoretinopathy (PVR), leading to subsequent retinal detachment. Histologic studies have also demonstrated localized foreign body reactions in rabbits in response to intravitreous injection of microspheres coated with poly lactic-co-glycolic acid, the same co-polymer that encases the Ozurdex implant (dexamethasone intravitreal implant; Allergan, Irvine, CA).5 These important safety considerations prompted the authors to devise a novel From the Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota. Originally submitted September 19, 2012. Accepted for publication December 10, 2012. The authors have no financial or proprietary interest in the materials presented herein. Address correspondence to Raymond Iezzi, MD, Department of Ophthalmology, Mayo Clinic, Rochester, MN 55905; 507-284-3701; Fax: 507-284-4612; Email: Iezzi.Raymond@mayo.edu. doi: 10.3928/23258160-20130313-10 March/April 2013 • Vol. 44, No. 2 181

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