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The dexamethasone implant (Ozurdex, Allergan, Inc, Irvine, CA) is an FDA-approved intravitreal corticosteroid for the treatment of noninfectious uveitis, macular edema following retinal vein occlusion, and most recently diabetic macular edema (DME). Case reports have surfaced regarding occasional malposition of the implant, particularly anterior segment migration (Afshar et al 2013; Coca-Robinot et al 2014; Khurana et al 2014). In this report, we describe a case of post-injection foveal adherence of a dexamethasone implant that was placed during vitrectomy requiring surgical repositioning.
A 63-year-old male with DME and proliferative diabetic retinopathy was initially treated with serial intravitreal bevacizumab injections and panretinal laser photocoagulation. Despite therapy, macular edema persisted with an associated epiretinal membrane (Figure) and was scheduled for a pars plana vitrectomy. He was enrolled in a prospective study examining the use of the dexamethasone implant at the time of vitrectomy for DME (Clinical trial ID: NCT01613716). He underwent vitrectomy with membrane peeling (i.e., ERM and internal limiting membrane) and panretinal photocoagulation. The dexamethasone implant was placed inferotemporally into the posterior chamber with standard technique. A 90% air-fluid exchange was performed and the implant remained mobile at time of surgical closure. The patient was instructed to avoid supine positioning.
On postoperative day 1, 80% air-fill remained and the dexamethasone implant was adherent to the fovea center. The patient was instructed to maintain upright positioning with intermittent supine positioning to allow for fluid to interact with the implant. Six days following surgery, a 40% air-fill remained and the implant was unchanged (Figure). VA was 20/125 and the patient noted a central linear scotoma. The next day, vitrectomy with implant repositioning was performed. The implant was carefully lifted from the macular surface with a soft-tip cannula and positioned to the mid-periphery (Figure). Intraoperative OCT confirmed removal without underlying gross alterations of the fovea. Prior to leaving the OR, the posterior pole was visualized with the patient upright. The implant gently moved to the inferior vitreous cavity. Strict upright positioning was performed.
Postoperatively, the implant remained in optimal position in the inferior vitreous cavity. The pre-existing retinal edema improved significantly and the VA improved to 20/20 (Figure). No additional complications were noted with resolution of edema.
Malposition of the dexamethasone implant has been reported in association with silicone oil after complicated retinal detachment repair. The implant migrated to the fovea and remained trapped beneath the silicone oil over a month (Afshar et al 2013). The implant spontaneously moved inferiorly, but a linear scotoma persisted with a corresponding pigmented ERM. Two cases of intralenticular injection of dexamethasone implant have also been reported (Coca-Robinot et al 2014). Cataract progression and increased intraocular pressure were noted. Recently, Khurana et al reported 18 eyes of 15 patients with dexamethasone migration into the anterior chamber (Khurana et al 2014). Sixteen of 18 cases developed corneal edema. In ten cases, the edema did not spontaneously resolve, and six cases required corneal transplantation despite implant removal, supporting early intervention for implant malpositon (Khurana et al 2014).
In our case, intravitreal dexamethasone implant was administered without any complication and the implant was confirmed to be freely mobile upon completing surgery but was firmly adherent to the fovea postoperatively. The muzzle velocity of the impact during introduction has been calculated at 0.8 m/s and decreases dramatically over time (Meyer et al 2012). Factors that may have contributed to adherence include the formation of fibrin following membrane peeling and the air-fluid exchange. Early repositioning was performed with an excellent anatomic and visual outcome. To our knowledge, this is the first report of a dexamethasone implant that is adherent to the macula in a fluid/air filled eye.
Grant Support: NIH/NEI K23-EY022947-01A1 (JPE); Ohio Department of Development TECH-13-059 (JPE, SKS); Research to Prevent Blindness (Cole Eye Institutional Grant); Machemer Foundation Fellowship (YI); Each provided support for research personnel and effort related to study design and completion.
Disclosures: YI: None; SKS: Bausch and Lomb (C), Allergan (R), Bioptigen (P), Zeiss (C), Synergetics (P); JPE: Bioptigen (C, P), Thrombogenics (C, R), Synergetics (P), Genentech (R), Leica (C), Zeiss (C), Alcon (C)