Design of Retinal Stent using Finite Element Analysis

Razvan Rusovici, Dennis Dalli, Kunal Mitra, Michael Calhoun, Michael Grace, Rudy Mazzocchi, and Gary Ganiban

Keywords

Retinal stent, Finite element , Shape memory alloy, Retina

Abstract

The motivation for the herein presented research stems from a new retinal reattachment procedure, which consists of carefully pressing the detached retina tissue into place via a shape memory alloy (SMA) and self-expanding stent. The initial study described in this article focused on modeling the mechanical interaction among stent and neighboring human eyeball tissues: retina, choroid and sclera. The study was performed via finite element analysis (FEA). The tissues were modeled with either hyperelastic or linear elastic material models in order to predict strain distributions on retina and the rest of the eye tissues due to stent placement. The FEA model included the following eyeball tissue: retina, choroid, sclera, cornea, zonular fibres, lens, and ciliary muscle. The simulations, shown for a sample stent configuration, have shown that the strain distribution developed due to stent placement was below levels which would induce permanent retina damage at the stent location. The simulations have shown that, by assuming that the retina was subjected to physiological internal ocular pressure (16.5 mmHg) in parallel to stent pressure (2200 Pa), the retinal strain reached a maximum of 2.67% , which was below a permanent damage strain threshold of 3.3%.

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