EXPOSURE RATE OF HYDROXYAPATITE SPHERES IN THE ANOPHTHALMIC SOCKET - HISTOPATHOLOGIC CORRELATION AND COMPARISON WITH SILICONE SPHERE IMPLANTS

We retrospectively reviewed enucleations and secondary anophthalmic so cket sphere implantations for a 3 year period. We compared the inciden ce of exposure of hydroxyapatite implants to the incidence of exposure of silicone implants. We found that the incidence of hydroxyapatite e xposure following enucleation was 3 of 27 (11.1%), and following secon dary anophthalmic socket implantation was 3 of 32 (9.4%). The incidenc e of silicone sphere exposure following enucleation was 0 of 48 (0%), and following secondary implantation was 1 of 30 (3.3%). The differenc e in exposure rate between hydroxyapatite and silicone reached statist ical significance in the enucleation group (p = 0.043) and in the comb ined enucleation and secondary implantation group (p = 0.033), but not in the secondary implantation group when considered separately. Osteo induction and fibrovascular infiltration were found in all hydroxyapat ite specimens examined histopathologically. In the exposed implants, l iquefaction necrosis of the implant occurred. In the nonexposed implan t, complete fibrovascular ingrowth was noted at 7 months. We believe t hat the hydroxyapatite anophthalmic sphere is associated with a higher incidence of exposure and postoperative inflammation when compared to silicone anophthalmic spheres. Patient selection and technique modifi cation may reduce the incidence of hydroxyapatite implant exposure.