Abstract

P 021

Intrastromal accumulation of air: a possible explanation for postoperative suture loosening after deep anterior lamellar keratoplasty (DALK) using the “big-bubble technique”

Joachim Braun, Carmen Rummelt, Ursula Schlötzer-Schrehardt, Friedrich E. Kruse, Claus Cursiefen
Universitäts-Augenklinik Erlangen

Objective
Deep anterior lamellar keratoplasty (DALK) is a new surgical method for the treatment of keratoconus. In contrast to penetrating keratoplasty, endothelium and descemet’s membrane are not replaced. They are separated from the main part of the stroma by intrastromal air injection (“big-bubble technique”). Postoperative suture loosening is more frequent using the big-bubble technique. Aim of our studies is to identify possible explanations of suture loosening by histological examinations of the excised corneal lamella of the recipient.
Methods
We used material of patients with deep anterior lamellar keratoplasty and made histological examinations of the excised anterior corneal lamella of the recipient. In addition to morphological studies we quantified intralstromal air.
Results
All examined lamellas contained intrastromal air, but there is a large variability (7.9% SD 11.2). The air is located at the periphery of the excised lamella distant to the epithelium and represents there up to 38.1% of the stromal volume. We detected no alteration of the Bowman’s layer and the epithelium.
Conclusions
Our results show that the air injection of “big-bubble DALK” causes intrastromal air accumulation in the cornea of the recipient. The intrastromal air may be accompanied by a decrease of mechanical stability explaining the higher frequency of suture loosening after big-buuble DALK compared to penetrating keratoplasty. In consequence, the surgeon should try to limit the injection of air to the excised central stroma.

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