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.

Wrapping of Porous Orbital Implant Using Acellular Dermal Allograft

PURPOSE: To investigate the results when using the acellular dermal allograft (SureDerm(R), Hans Biomed Co., Korea) as a new wrapping material for porous orbital implants. METHODS: The charts of 11 patients who underwent either primary or secondary insertion of Medpor(R) orbital implants after enucleation or a new insertion after removal of previous orbital implants were reviewed. Medpor(R) orbital implants either 18 or 20 mm were wrapped with SureDerm(R) in 4x4 cm sections that were 1-mm-thick. Four rectus muscles were fixed to the SureDerm(R) wrapped implant, and a conjunctival suture was made with 6-0 Vicryl. All patients had follow-up periods longer than 10 months and were evaluated to determine the success of wrapping and to identify any complications. RESULTS: The average age of the patients was 48.3 years. The patients wore artificial eyes for 9 weeks after the operation, and the follow-up periods were 22.4 months on average. There was no case of implant or SureDerm(R) exposure, inflammation, and other significant complications except in one case that required fornix reconstruction to allow the subject to wear an artificial eye. CONCLUSIONS: Acellular dermal allograft appears to be a good substitute material if preserved sclera is not available when inserting orbital implants with wrapping.

Expanded Polytetrafluoroethylene as a Wrapping Material for Porous Polyethylene Orbital Implant

PURPOSE: To investigate the possibility of expanded polytetrafluoroethylene (e-PTFE) as a wrapping material for porous polyethylene orbital implant. METHODS: Two groups of 6 female New Zealand albino rabbits underwent enucleation with placement of a 12 mm porous polyethylene orbital implant wrapped in simple e-PTFE in one group (group 1) and macro-porous e-PTFE in the other group (group 2). Histopathologic sections of the implants obtained at 4, 6, 8 weeks were compared on the extent of fibrovascular ingrowth, percentage of the area of proliferated vessel, and grade of fibrosis between the two groups. RESULTS: There was no implant exposure or severe inflammation in group 1 and 2 during the observation. The extent of fibrovascular ingrowth differs only at 4 weeks. Group 1 showed less fibrovascular ingrowth (until outer 1/3) at anterior half compared with posterior one, but there was no difference between anterior and posterior half in group 2 (until middle 1/3). The percentage of the area of the proliferated vessels was higher in group 2 than group 1 at both anterior and posterior half, and the anterior/posterior ratio of the area of vessels was also higher in group 2 than group 1. The grade of fibrosis was higher in group 2 than group 1 at 4, 6, and 8 weeks. CONCLUSIONS: Macro-porous e-PTFE almost didn't disturb fibrovascular ingrowth into the orbital implant, so macro-porous e-PTFE can be used safely as a wrapping material for porous polyethylene orbital implant.

Clinical Results of Hydroxyapatite Orbital Implantations using Autologous Sclera as a Wrapping Material

PURPOSE: To evaluate the clinical result of hydroxyapatite implantation using autologous sclera as wrapping material. METHODS: From December 2001 to February 2003, we performed 20 cases of hydroxyapatite implantation with autologous sclera as wrapping material. Eyes were enucleated for severe phthisis because evisceration could not provide adequate space for hydroxyapatite implantation or secondary hydroxyapatite implantation after prior evisceration. Postoperative complications were evaluated at postoperative 1 week, 2 weeks, 3 weeks - 1 month, 2 months, 3 months, and every 2 or 3 months thereafter. RESULTS: The mean follow up period was 12.1 +/- 4.52 months (4~18 months). During the follow up period, conjunctival erosions developed in 2 cases, which were controlled by conservative management only. No such postoperative complications as implant exposure, orbital infection, extrusion, inflammatory reaction occured. CONCLUSIONS: Autologous sclera is the suitable wrapping material of hydroxyapatite implant when enucleation is needed in primary surgery for severe phthisis, or for secondary hydroxyapatite implantation after prior evisceration surgery.

Bovine Pericardium as a Wrapping Material for Hydroxyapatite Orbital Implant

PURPOSE: To investigate the usefulness of a processed bovine pericardium(Lyoplant(R)) as a wrapping material for hydroxyapatite orbital implant. METHODS: The authors carried out hydroxyapatite orbital implantation with a processed bovine pericardium(Lyoplant(R)) as a wrapping material for hydroxyapatite sphere in 14 enucleation cases from October 1998 to May 2000, and evaluated postoperative complications, fibrovascular ingrowth and implant or prosthesis motility. RESULTS: Physical properties of bovine pericardium, such as tensile strength, flexibility, suture characteristics, were good. Complications were developed in 8 cases(5 eyes), but there was no serious complication such as an implant exposure. Fibrovascular ingrowth and implant or prosthesis motility were satisfactory. CONCLUSION: The authors suggest bovine pericardium(Lyoplant(R)) as an effective wrapping material for hydroxyapatite orbital implant.

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.