Fibrovascular ingrowth in porous ocular implants: The effect of material composition, porosity, growth factors, and coatings

Purpose: Fibrovascular ingrowth into various porous ocular implants as a fu nction of implant material composition, porosity, growth factors, and coati ngs was investigated in a pilot study in an animal model. Methods: Eighty-one New Zealand white rabbits underwent unilateral enucleat ion and implantation with ocular implants composed of the following materia ls: coralline hydroxyapatite (HA) with 200-mu m pores (HA200) or 500-mu m p ores (HA500), synthetic HA (synHA), and high-density porous polyethylene (P P). The HA200, HA500, and PP implants were implanted untreated or after tre atment with recombinant human basic fibroblast growth factor (Rh-bFGF). Nin e HA500 implants were implanted after coating with calcium sulfate (plaster of Paris) to provide a smooth outer surface. Implants were harvested at 1- , 2-, 4-, or 8-week intervals and were examined histologically. Results: A significant difference was found between untreated HA500 and PP, with PP showing better ingrowth. There was no significant difference betwe en unheated HA and PP, nor between untreated HA500 and synHA. Significant i ncreases in ingrowth were found in HA200 compared with HA500, and in Rh-bFG F-treated implants compared with unheated controls. The calcium sulfate-coa ted implants showed less vascularization compared with the uncoated implant s, although the difference was not significant. Conclusions: Fibrovascular ingrowth occurred earlier in HA200 implants than in HA500 implants, and was enhanced when implants were treated with Rh-bFG F.