Tectonic lamellar keratoplasty with acellular corneal stroma in high-risk corneal transplantation

PURPOSE: Tectonic lamellar keratoplasty (TLKP) is a primary surgical procedure to improve the condition of the recipient bed in high-risk corneal transplantation. It is usually performed for a secondary optical penetrating keratoplasty (PKP). The present study was undertaken to explore a new strategy for TLKP using acellular corneal stroma (ACS) prepared by decellularization. METHODS: ACS for TLKP was prepared from cat cornea by decellularization. The efficiency of the decellularization was examined by hematoxylin and eosin (H&E) staining and through DNA content analysis. Twenty-eight New Zealand white rabbits, as recipients, were assigned to one of two groups that had different material for their TLKP. The TLKP was combined with a central optical PKP as a single-stage procedure. Either ACS or fresh cat corneal lamella, 11.25 mm in diameter, was used for the TLKP in these two groups. After TLKP, a 6.5-mm full-thickness cat cornea was placed in the central cornea of each recipient rabbit for PKP. Clinical outcomes and the histology of the transplants were compared post-operatively. RESULTS: ACS for TLKP prolonged the survival of the transplants. The mean survival time of the transplants in the ACS group (36.4±4.3 days) was longer than for those in the control group (14.0±2.2 days, p<0.05). The ACS group showed a significantly smaller neovascularization area compared to the control group. The areas of corneal neovascularization were 5.3±1.1 mm(2) and 45.2±4.9 mm(2) (p<0.05), respectively, after two weeks, and 25.1±4.7 mm(2) and 105.3±12.4 mm(2) (p<0.05), respectively, after four weeks. Histology revealed that fewer inflammatory cells were infiltrating the transplants in the ACS group than those in the control group. CONCLUSIONS: The use of ACS for TLKP prolonged the survival of corneal transplants, reduced corneal neovascularization, and prevented from infiltration of inflammatory cells. It is a feasible and effective strategy to prolong the survival of transplants in high-risk corneal transplantation.