Abstract
Abstract: :
Purpose: Hydrogel or hydrophilic gel is the generic terminology for a biocompatible osmotic expansile material used in contact lenses, scleral buckles and most recently orbital expanders. Orginally formulated as 2-hydroxyethyl methacrylate hydrogels, the material was thought ideal for scleral buckle use due to its softness and elasticity but proved brittle. Crosslinking and polymerization with alkyl acrylate imparted strength and was used in the final formulation of Miragel implants (MIRA, Walthem, MA). Expansion was controlled by variations in hydration. However, a known, late complication is implant extrusion. We present 3 unique complications from Miragel buckle use – orbital cellulitis mimicry, forniceal shortening with orbital prosthetic intolerance, and orbital pseudotumor. Methods: A retrospective chart review was performed on three subjects referred to a tertiary-care oculoplastics practice with unknown hydrogel scleral buckle complication. Demographics, imaging studies, and pathological specimens were reviewed. Results: All 3 patients had a history of encircling Miragel scleral buckle placed for retinal detachment. The mean time from implantation to presentation was 10.7 years (range 7 to 15). One patient had progressive inability to wear an evisceration prosthesis due to a shortening fornix. A second patient had an acute onset of orbital cellulitis in which a CT scan revealed an enlarged buckle and no abscess. Surgical exploration revealed no purulent material. A third patient presented with a slow growing orbital mass in the inferior orbit. In all cases surgical removal of the expanded buckle relieved symptoms. Pathological examination revealed no inflammatory reaction in all cases. Conclusions: Although the Miragel scleral band is designed to expand in a controlled fashion, a long-term complication is over expansion. Although uncommon, this can cause buckle extrusion, or in this series prosthetic intolerance, an orbital cellulitis picture, or an orbital pseudotumor. This may be due to a chemical change in the composition of the hydrogel polymer which leads to exuberant expansion. Although production of the Miragel implant ceased in 1999, patients with Miragel scleral buckles should be followed long-term for the possibility of this spectrum of complications. Furthermore, newer uses of hydrogels, such as in orbital expanders of differing chemical make-up, should be observed for similar, long-term complications.
Keywords: orbit • inflammation • retinal detachment