Abstract
Purpose::
To review the clinical and histologic features of porous orbital implants requiring explantation.
Methods::
We reviewed the charts and histological findings of 22 patients requiring explantation of porous orbital implants between 1996 and 2006. Clinical data recorded included age, gender, primary surgery, type of implant, and symptoms and signs leading to explantation. We recorded histologic data including the amount of fibrovascular in-growth, amount of tissue necrosis, type of inflammation, and presence of bacterial colonies.
Results::
The orbital implants included 18 Medpor, 3 hydroxyapatite, and 1 bioceramic. The primary surgeries were 14 enucleations, 6 eviscerations and 2 secondary implants. Clinical history included anterior implant exposure in all cases. Histology showed less than 50% fibrovascular in-growth in 20 implants, tissue necrosis in 7, predominantly acute or mixed inflammation in 19 and mainly chronic inflammation in the remaining. We identified gram positive cocci in clusters or chains in 16 implants.
Conclusions::
Exposure of porous implants has been reported to occur in 5-20% of cases. While these can usually be safely repaired, a small minority may continue to expand and develop signs of infection, necessitating removal. This paper is the largest review of such explanted spheres including all the porous materials currently used. We suggest that anterior exposure allows bacterial colonization and the development of a heavy inflammatory infiltrate. Poor tissue in-growth and secondary zones of necrosis may limit the penetrance of topical or systemic antibiotic therapy leading to the necessity for explantation.
Keywords: inflammation • orbit • pathology: human