title: Chronic exposure of hydroxyapatite orbital implants: cilia implantation and epithelial downgrowth.
abstract: OBJECTIVE
  To describe previously unreported histologic findings in two patients who developed chronic implant exposure and abscess formation within hydroxyapatite orbital implants.
  
  
  METHODS
  Surgically removed implant specimens were processed for histopathologic examination and stained for microorganisms. Each patient's clinical course, 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 shafts 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 fibrovascular 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 downgrowth. Both of these may be contributing factors in the development of serious implant infections.
authors.affiliation: Department of Ophthalmology, University of California at San Diego School of Medicine, La Jolla 92093-0946, USA.
authors.forename: J W
authors.initials: JW
authors.lastname: Kim
authors.forename: D O
authors.initials: DO
authors.lastname: Kikkawa
authors.forename: A
authors.initials: A
authors.lastname: Aboy
authors.forename: B J
authors.initials: BJ
authors.lastname: Glasgow
mesh_terms: D000038:Abscess / Q000209:etiology / Q000473:pathology / Q000601:surgery; D000328:Adult; D020099:Coated Materials, Biocompatible / Q000009:adverse effects; D020878:Device Removal; D017886:Durapatite; D004847:Epithelial Cells / Q000473:pathology*; D005129:Eye Foreign Bodies / Q000209:etiology* / Q000473:pathology / Q000601:surgery; D006197:Hair / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009916:Orbital Diseases / Q000209:etiology* / Q000473:pathology / Q000601:surgery; D020273:Orbital Implants / Q000009:adverse effects*; D011475:Prosthesis Failure
chemical_list: D020099:Coated Materials, Biocompatible; D017886:Durapatite