Chronic exposure of hydroxyapatite orbital implants: Cilia implantation and epithelial downgrowth

Purpose: To describe previously unreported histologic findings in two patie nts who developed chronic implant exposure and abscess formation within hyd roxyapatite orbital implants. Methods: Surgically removed implant specimens were processed for histopatho logic examination and stained for microorganisms. Each patient's clinical c ourse, socket appearance, and exposure management were reviewed. Results: Histopathologic examination of case 1 showed a channel of necrosis leading from the anterior surface of the implant to its center. Hair shaft s were discovered embedded within this channel. Histopathologic examination of the site of chronic exposure in case 2 showed epithelial ingrowth into the pores of the implant. Both spheres in this report indicated limited fib rovascular ingrowth and abscess formation. Conclusions: Chronic exposure of hydroxyapatite implants allows a portal of entry for extraneous hair shafts and also can lead to epithelial downgrowt h. Both of these may be contributing factors in the development of serious implant infections.