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 mm² and 45.2±4.9 mm² (p<0.05), respectively, after two weeks, and 25.1±4.7 mm² and 105.3±12.4 mm² (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.