The Survival of Freely Grafted Orbital Fat on Porous Polyethylene Orbital Implants in the Rabbit

PURPOSE: To investigate the long term survival of orbital fat grafted on a Medpor® implant as a method of preventing porous polyethylene orbital implant (Medpor®) exposure in anophthalmic sockets. METHODS: In one orbit in each of 8 rabbits, a small amount of retrobulbar orbital fat was grafted between the anterior surface of the Medpor® implant and overlying conjunctiva, during the enucleation and Medpor® implantation procedure. Two rabbits were sacrificed at 2, 4, 8 and 12 weeks postoperatively and grafted orbital fats were examined by light microscopy. RESULTS: Grafted orbital fat was well-maintained at 2 and 4 weeks, postoperatively. However, fat amounts were significantly reduced at 8 weeks, and viable fat was barely visible at 12 weeks. CONCLUSIONS: In rabbits, orbital fat grafted on Medpor® implants was gradually resorbed, and the fat-occupied volume was not maintained.