title: Hydroxyapatite orbital implants. Experience with 100 cases.
abstract: BACKGROUND
  The hydroxyapatite (HA) intraorbital implant is a relatively new implant made from the porous skeleton of a coral species which allows fibrovascular ingrowth and therefore tissue integration. After fibrovascular ingrowth, a hole can be drilled in the implant and a motility peg inserted to increase movements of the prosthesis by coupling the implant to the prosthesis.
  
  
  METHODS
  The records of the first 100 cases of HA intraorbital implants inserted by the one surgeon were analysed for complications, pain and nausea postoperatively, length of hospital stay, and further surgical procedures required. A series of acrylic implants inserted by the same surgeon was used for comparison.
  
  
  RESULTS
  Twenty-five primary and 75 secondary HA implants were performed in patients ranging from six to 74 years of age. All were covered in donor sclera. Follow-up was three to 34 months (mean 16.9, median 17.0). Complications occurred in 15 patients and included too large an implant (seven cases) requiring surgical reduction, scleral exposure in three (repair required in one), an early small exposure of the coral in one case, late thinning of the conjunctiva and later exposure of the implant in one, and shallowing of the inferior fornix requiring mucous membrane grafting in three. No implants migrated, extruded or became infected. Of 80 patients beyond six months follow-up, 28 (35%) had insertion of motility pegs, and six (7.5%) of these suffered minor complications related to the peg. Compared to patients having acrylic implants, the postoperative analgesic requirements and length of hospital stay were significantly greater for the HA patients.
  
  
  CONCLUSIONS
  Hydroxyapatite intraorbital implants represent a significant advance over other implants and offer a more stable, safe alternative. They also offer the possibility of improved prosthesis motility. The additional cost of the implant, prolonged hospital stay and postoperative pain, should be considered in recommending such implants to patients either as primary or secondary implants.
authors.affiliation: Royal Victorian Eye and Ear Hospital, Royal Melbourne Hospital.
authors.forename: A
authors.initials: A
authors.lastname: McNab
mesh_terms: D000179:Acrylates; D000293:Adolescent; D000328:Adult; D000368:Aged; D001672:Biocompatible Materials; D002648:Child; D017886:Durapatite; D015353:Eye Enucleation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009915:Orbit / Q000601:surgery*; D011183:Postoperative Complications; D019736:Prostheses and Implants; D012086:Reoperation
chemical_list: D000179:Acrylates; D001672:Biocompatible Materials; D017886:Durapatite