HYDROXYAPATITE ORBITAL IMPLANTS - EXPERIENCE WITH 100 CASES

Background: The hydroxyapatite (HA) intraorbital implant is a relative ly 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 mot ility peg inserted to increase movements of the prosthesis by coupling the implant to the prosthesis. Method: The records of the first 100 c ases of HA intraorbital implants inserted by the one surgeon were anal ysed for complications, pain and nausea postoperatively, length of hos pital stay, and further surgical procedures required. A series of acry lic implants inserted by the same surgeon was used for comparison. Res ults: Twenty-five primary and 75 secondary HA implants were performed in patients ranging from six to 74 years of age. All were covered in d onor sclera. Follow-up was three to 34 months (mean 16.9, median 17.0) . Complications occurred in 15 patients and included too large an impl ant (seven cases) requiring surgical reduction, scleral exposure in th ree (repair required in one), an early small exposure of the coral in one case, late thinning of the conjunctiva and later exposure of the i mplant in one, and shallowing of the inferior fornix requiring mucous membrane grafting in three. No implants migrated, extruded or became i nfected. Of 80 patients beyond six months follow-up, 28 (35%) had inse rtion of motility pegs, and six (7.5%) of these suffered minor complic ations related to the peg. Compared to patients having acrylic implant s, the postoperative analgesic requirements and length of hospital sta y were significantly greater for the HA patients. Conclusions: Hydroxy apatite intraorbital implants represent a significant advance over oth er 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 pri mary or secondary implants.