Treatment of Exposed Hydroxyapatite Orbital Implants Wrapped with a Synthetic Dura Substitute

PURPOSE: To describe cases of exposed hydroxyapatite (HA) implants wrapped with the synthetic dura substitute Neuro-Patch treated via simple Neuro-Patch removal. METHODS: The medical records of seven patients who experienced exposure of their HA implant were reviewed. All patients had been enucleated and implanted with HA wrapped with Neuro-Patch. For treatment, Neuro-Patch was removed to the greatest extent possible. After applying local anesthesia with lidocaine, blunt dissection was performed to separate the conjunctiva and Neuro-Patch via the site of exposure. Pressure was applied to the remaining Neuro-Patch with forceps and removed with scissors. RESULTS: Neuro-Patch was visible at the area of exposure in all patients. No surgery beyond initial Neuro-Patch removal was necessary in six of the seven patients. In five cases, the exposed area began to heal rapidly after Neuro-patch removal without primary closure of the defect. In one case, the Neuro-Patch material and all necrotic tissue was removed aggressively due to inflammation around the orbital implant. Lastly, an infection was noted in one case, prompting complete removal of the Neuro-Patch–wrapped HA implant. CONCLUSIONS: Wrapping material may hinder implant vascularization. Exposure of HA in wrapped implants can be successfully treated by a simple removal procedure if detected and managed early.

Study on the possible factors leading to complications of hydroxyapatite orbital implantation / 国际眼科杂志(Guoji Yanke Zazhi)

·Hydroxyapatite ( HA ) orbital implant has been widely used since it was developed due to its many advantages. It is one of the ideal materials to fill the orbital volume after enucleation or evicseration. However, it still causes complications, and some complications such as severe eye exposure may require reimplant surgery. The paper reviews the clinical application of HA orbital implant, the possible factors leading to complications of HA orbital implantation and the treatments for several common complications. The review aims to provide some help to readers.

Treatment of Exposed Hydroxyapatite Orbital Implant Using Acellular Dermal Allograft

PURPOSE: To investigate the results of acellular dermal allograft (SureDerm(R), Hans Biomed Co., Korea) as a new covering material in the exposure of hydroxyapatite orbital implant. METHODS: SureDerm graft was performed in 5 patients with exposed hydroxyapatite orbital implant. Under local anesthesia, the anterior surface of the exposed implant was trimmed and the designed SureDerm was sutured at the margin of the sclera with 6-0 Vicryl. Finally, conjunctival suture was done. The patients were followed up regularly until postoperative 10 months. RESULTS: The average diameter of exposed implant was 9.6 X 9.0 mm. The grafted SureDerm had survived in all patients at postoperative 10 months and exposure of implant was treated successfully in all cases. CONCLUSIONS: We consider that acellular dermal allograft will be a good replacing material when preserved sclera is not available. It also features the advantage of avoiding the intricate harvesting procedure and the scarring of the donor site in dermo-fat graft.

Comparative Study between Magnetic Resonance Imaging and Technetium-99m-MDP Bone SPECT in The Evaluation of The Hydroxyapatite Orbital Implant: Report of Two Cases

Because of the excellent cosmetic and functional reconstruction compared with other integrated implant, hydroxyaptite is commonly used in recently. This excellent cosmetic effect is acquired by successful integration between hydroxyapatite and normal orbital tissue by fibrovascular tissue. We performed simultanously magnetic resonance imaging and bone scan to two patients undergoing hydroxyapatite orbital implantation after evisceration and evaluating fibrovascular ingrowth into the implant between MRI and bone scan and observed ingrowing pattern of fibrovascular tissue into the hydroxyapatite after evisceration especially. MRI studies are somewhat more valuable imaging than bone scan. Vascularization into the implant were started from inserted portion of extraocular muscle and posterior aspect of implant and slowly progressed to the center of hydroxyapatite sphere. There was no relation between inserted duration and fibrovascular ingrowth due to individual variation. And constrast enhanced MRI appears to be the best imaging method for evaluating the hydroxyapatite orbital implant and its fibrovascular ingrowth. In spite of low specificity compared with MRI, bone scan is also valuable method for the evaluating vascularization of the hydroxyapatite because of low cost and easy follow-up.

Histopathologic Comparison of Vascularization between Dacron and Donor Sclera as Wrapping Material in Hydroxyapatite Implantation

Recently, a hydroxyapatite sphere has been increasingly used as a buried integrated orbital implant for the great improved motility of the prosthesis after enucleation. To allow more rapid ascess of vasculature into the hydroxyapatite implant, Dacron as a new synthetic wrapping material of the implant for anophthalmic sockets had been used and compared histologically with donor sclera in rabbits. At 4 weeks after implantation, fibrovascular ingrowth was found mainly near the scleral windows, where fibrosis extended 2 mm centrally in scleral-wrapped implants. In Contrast, in Dacron-wrapped implants, there was extensive fibrovascular infiltration through Dacron filaments and windows as well, making the hydroxyapatite sphere completely invested with fibrovascular tissue to the center within 4 weeks of implantation. Thus, Dacron as a new wrapping material appears to allow a more rapid vascularization into the hydroxyapatite implant than other collagen material without any serious complications, resulting in early rehabilitation with an artificial eye.