Session Title: Cornea surgical I
Session Date :08 October 2013 | Session Time: 08:00 - 10:30
Paper Time: 08:06
First Author: M. Dickman The Netherlands
Co. Authors : P. Steijger Vermaat Y. Schuchard F. van Marion T. Berendschot F. van den Biggelaar R.Abstract Details:
To determine the thickness predictability associated with single pass harvesting of ultrathin (<100 µm) endothelial grafts using innovative microkeratome technology and to determine whether corneas previously discarded because of large senile arcus (arcus free diameter <8 mm) are suitable for (ultrathin) posterior lamellar keratoplasty.
Euro Cornea Bank ,Beverwijk, The Netherlands. University Eye Clinic Maastricht, Maastricht, The Netherlands.
Twenty-two paired donor corneas (n=44) unsuitable for transplantation because of anterior stromal pathology (n=22, group 1) or a large senile arcus (n=22, group 2) were organ cultured under standard conditions. All corneas were transferred to an organ culture medium supplemented with 6% Dextran 24 hours prior to dissection for deswelling. Posterior lamellar grafts were harvested using a Gebauer microkeratome (SLc; Gebauer Medizintechnik) equipped with either a 400, 450, 500 or a 550 µm heads aiming at a residual thickness < 100 µm. Central corneal thickness (CCT) was measured using ultrasound pachymetry (Corneo-gage plus; Sonogage) and anterior segment optical coherence tomography (Casia SS-1000; Tomey). Scanning and transmission electron microscopy and histopathological analysis were performed to evaluate stromal bed smoothness and lamellar lipid content. Linear Mixed Model (LMM) analysis was performed to quantify the differences in thickness between cut and uncut corneas and between groups.
Lamellar dissection was successful in all cases. Mean (±SD) posterior lamellar thickness (65 ± 13 µm, 95% C.I. [58,72]) was significantly thinner than <100 µm (p<0.001). There was no significant difference in lamellar thickness between dissected corneas of both groups (p = 0.24). Microkeratome depth plate was found to explain 26% of the variability in graft thickness (?=0.180, p=0.036). Graft thickness was not influenced by predissection thickness, incubation time or group. Histopathological and EM analysis revealed no differences in surface roughness or lamellar lipid content between lamellae of both groups.
Single pass microkeratome dissection enables predictable precut harvesting of ultrathin (65 ± 13) lamellar grafts for endothelial keratoplasty. Donor corneas deemed unsuitable for transplantation because of large senile arcus may still be suitable for (ultrathin) posterior lamellar keratoplasty. FINANCIAL INTEREST: NONE