[Experience with orbital implants in particular with porous hydroxyapatite materials]

Various materials have been developed since the first implantation of a hydroxyapatite sphere in 1985. They are similar to the porous basic structure and imitate the biological behavior of coralline implants. This article presents own clinical experience with hydroxyapatite implants from 1993 to 2003 and compares own results and other porous orbital implants in the international scientific literature.

The original hydroxyapatite implant is well tolerated and implant extrusion is rare. A retrospective analysis of 357 patients regarding this complication shows an extrusion rate of 2.6% over 10 years. The subjective positive tolerance of 71.2% corresponds to the results of international studies. After several stages of development the synthetic product (FCI3) is now comparable with the original product with regard to operative complications and subjective compatibility. Both orbital implants should be used with a protective covering to avoid premature extrusion and to facilitate suturing the extraocular muscles anterior. When using material from humane donors the material must be guaranteed to be completely sterile. The use of vicryl as an orbital plomb wrapping leads to contradictory reports in the literature. Hydroxyapatite ceramics in combination with silicone india rubber represent an alternative to the materials listed above and in this case a wrapping of the orbital plomb is unnecessary. Spherical orbital implants made of aluminum oxide (bioceramic implant) are an alternative to corraline hydroxyapatite implants. Because of their porous,crystalline structure bioceramic implants vascularize well. Porous polythylene orbital implants,which are not available in Germany, are economical, but due to their porosity and vascularization properties they are not comparable with pure hydroxyapatite or hydroxyapatite ceramics.

The dynamic development of the infant anopthalmus adapted to the size growth of the orbita and the exact volume replenishment of the adult orbita cannot yet be fulfilled with the presently available porous hydroxyapatite materials and is the subject of future research.