Superficial Keratectomy, Limbal Autotransplantation and Amniotic Membrane Transplantation in the Treatment of Severe Chemical Burns of the Eye

Abstract

Kozak, I., A. Trbolova, Z. ·evaikova, T. Juhas, V. Ledeck˘: Superficial Keratectomy, Limbal Autotransplantation and Amniotic Membrane Transplantation in the Treatment of Severe Chemical Burns of the Eye. Acta Vet. Brno 2002, 71: 85-91. Alkali burns are the most serious of chemical injuries of the anterior segment of the eye. Their treatment is aimed at preservation and/or restoring limbal stem cells and reconstruction of the ocular surface. Autologous limbal transplantation is used in management of damaged limbal stem cells and amniotic membrane transplantation in reconstruction of the burnt ocular surface. The aim of this study was to clinically and histopathologically evaluate treatment of severe chemical eye injuries. Limbal autograft transplantation and transplantation of amniotic membrane were combined with superficial lamellar keratectomy. Fifteen New Zealand white male rabbits were used in the experiment. General anaesthesia was induced before 2.5 N NaOH solution was applied to one eye of each animal. The surgery of injured eye consisted of following steps: after keratectomy of necrotic cornea limbal graft from the contralateral eye was transferred on the injured eye and covered by amniotic membrane which was attached 5-7 mm from the limbus. In the post-operative period Infectoflam® eye drops (Novartis) were applied 4 times daily for 4-6 weeks. Clinical evaluation was done regularly at 2 and 4 weeks and 4 and 9 months after surgery. We evaluated corneal edema, vascularization, erosion, conjunctival hyperemia, limbal ischemia, blepharospasm, ocular discharge, tear film stability and symblepharon formation. Two eyes spontaneously perforated at the end of the first month. Corneal edema was most intense at 4 weeks and improved at the end of follow-up in 8 eyes (62%). Vascularization was most prominent at 4 weeks in all cases and after 9 months was local in 5 eyes (38%) and diffuse in 3 eyes (22%). Complete re-epithelization was achieved in 9 eyes (68%). Conjunctival hyperemia was present in all eyes at 2 weeks and in 2 eyes (15%) at 9 months. Limbal ischemia was present in all eyes at 2 weeks and in 5 eyes (38%) at the end of follow-up period. Blepharospasm was present in 2 eyes (15%) at 4 months and disappeared at the last control. Purulent discharge was most intense at 2 weeks (9 eyes - 69%), after 9 months we noticed only increased watering in 2 eyes (15%). Symblepharon was initially seen in 5 eyes (38%) and was noticed in 3 eyes (22%) at the end of follow-up period. Our results show that amniotic membrane transplantation after superficial keratectomy combined with limbal autograft transplantation after severe alkali burn significantly contributes to reparative process of the ocular surface. Chemical burns, experiment, limbal autotransplantation, amniotic membrane transplantation The integrity of the ocular surface is kept by corneal, limbal and conjunctival epithelia together with the presence of tear film. The proper function of these structures represents a universal protective mechanism of the anterior segment of the eye. When these structures and their functions are altered, ocular surface reconstruction becomes problematic. In alkali burns, the most serious chemical injuries, saponification of fatty acids in cell membranes occurs which enhances penetration of the noxious substance to deeper layers of the anterior segment of the eye. The most important prognostic factors in clinical evaluation of the chemical eye injuries is assessment of the corneal transparency and the status of the limbal stem cells. Based on these criteria chemical injuries are classified into 4 grades