Long-Term Clear Graft Survival and Chronic Endothelial Cell Loss Following Posterior Lamellar Keratoplasty
Diseases of the corneal endothelium (Fuchs endothelial dystrophy, bullous keratopathy, and endothelial failure following penetrating keratoplasty) count for the most frequent indications for corneal transplantation. Instead of replacing all five layers of
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Long-Term Clear Graft Survival and Chronic Endothelial Cell Loss Following Posterior Lamellar Keratoplasty Philip Maier and Thomas Reinhard
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Introduction
Diseases of the corneal endothelium (Fuchs endothelial dystrophy, bullous keratopathy, and endothelial failure following penetrating keratoplasty) count for the most frequent indications for corneal transplantation. Instead of replacing all five layers of the cornea (epithelium, Bowman layer, stroma, Descemet membrane, endothelium) by penetrating keratoplasty (PK), which has first been performed by Eduard Zirm [1–3] in 1905, nowadays techniques for the selective replacement of the diseased corneal endothelium are preferred. This has first been suggested by Tillet in 1956 [4] to avoid characteristical complications following PK (e.g. high irregular astigmatism and wound healing problems). The technical principle of this kind of posterior lamellar keratoplasty or endothelial keratoplasty (EK) was to excise the host’s posterior stroma including Descemet membrane and endothelium and to replace it by identical lamellar graft prepared from the donor lamella. However, due to interface irregularities between host and donor stroma the visual results were not satisfying for the patients. One important technical step in improving posterior lamellar keratoplasty was the introduction of descemetorhexis by Melles et al. [5], where the stroma of the recipients cornea is not manipulated and only the Descemet membrane including the diseased endothelial cells is removed completely [6]. By avoiding manipulations of the recipient’s posterior stroma the clinical results could be improved as the lamellar graft could be attached to a smooth surface of the posterior stroma. In case of Descemet stripping endothelial keratoplasty (DSEK) the lamellar graft is manually prepared and consists of posterior stroma, Descemet membrane, and endothelium of the donor. It is transferred into the anterior chamber via a corneoscleral or clear cornea incision using special surgical instruments, unfolded and sutureless attached to P. Maier • T. Reinhard (*) Eye Center, Faculty of Medicine, University Hospital Freiburg, Killianstr. 5, 79106 Freiburg, Germany e-mail: [email protected] © Springer International Publishing Switzerland 2017 C. Cursiefen, A.S. Jun (eds.), Current Treatment Options for Fuchs Endothelial Dystrophy, DOI 10.1007/978-3-319-43021-8_14
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the posterior stroma of the recipient’s cornea by an air bubble. Regarding DSEK one problem is the manual preparation process of the lamellar graft leading to graft preparation failures in some cases [7]. To overcome these problems of complete manual graft preparation the separation of the stromal lamellae can be performed using a microkeratome, by which a 400–500 μm thick layer of the anterior part of the donor cornea can be cut leaving a 80–150 μm thick lamella consisting of posterior stroma, Descemet membrane, and endothelium (Descemet stripping automated endothelial keratoplasty, DSAEK). T
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