The bioceramic orbital implant: a new generation of porous implants.

PURPOSE: The authors describe a new generation of porous orbital implant made of aluminum oxide (Al2O3) and compare it with the hydroxyapatite orbital implants (Bio-Eye and FCI hydroxyapatite). METHODS: The authors examined the new implant macroscopically, with chemical analysis and microscopically with scanning electron microscopy. Animal implantation studies were performed using six adult male New Zealand albino rabbits. Implant vascularization was evaluated by means of magnetic resonance imaging and histopathologic sectioning. RESULTS: The Bioceramic orbital implant was found to have very uniform pore structure with an average pore size of 500 microm. The implant was 99.9% aluminum oxide on x-ray diffraction. Magnetic resonance imaging in vivo vascularization studies demonstrated enhancement of the implant to its center by 4 weeks after implantation in the rabbit. Histopathologically, fibrovascularization occurred uniformly throughout the implant and was noted by 4 weeks. CONCLUSIONS: The Bioceramic orbital implant represents a new porous orbital implant that has a very regular and extensive interconnected pore system, is as biocompatible as hydroxyapatite, is easy to manufacture, structurally strong, and free of contaminants. It is manufactured with no disruption to marine life ecosystems as may occur in the harvesting of coral for other orbital implants. It is less expensive than currently available hydroxyapatite implants and was approved by the U.S. Food and Drug Administration in April 2000.

Hydroxyapatite implant wrapping materials: analysis of fibrovascular ingrowth in an animal model.

PURPOSE: To compare the influence of seven currently available spherical orbital implant wraps on host fibrovascularization of a hydroxyapatite (HA) orbital implant. METHODS: Five groups of 3 (15 total) adult male New Zealand albino rabbits underwent enucleation with placement of a 12-mm HA implant wrapped in high-porosity expanded polytetrafluoroethylene (e-PTFE), processed bovine pericardium, or processed human pericardium, sclera, or fascia lata. Magnetic resonance imaging before and after the intravenous administration of gadolinium-diethylenetriamine pentaacetic acid (DTPA, 0.1 mol/kg) was performed immediately before exenteration. Five rabbits (one with each of the different implant wraps) were killed at 4, 8, and 12 weeks, and the operated socket was exenterated. Histopathologic sections of the implants were then compared with the results of our previous study using polyglactin 910 mesh and autologous sclera as HA orbital implant wraps. RESULTS: Complete fibrovascularization of all the implants occurred by 12 weeks; however, HA implants wrapped with sclera, polyglactin mesh, and e-PTFE appeared to undergo more rapid fibrovascularization than spheres wrapped with other materials. CONCLUSIONS: Although all of the implant wraps studied may be suitable substitutes for donor sclera, we prefer polyglactin mesh because it is readily available, inexpensive, and without risk of transmissible diseases.

Mucoepidermoid carcinoma of the conjunctiva: a series of three cases.

OBJECTIVE: To detail the clinical presentation and outcomes of currently available treatments for mucoepidermoid carcinoma of the conjunctiva (MCC). DESIGN: Retrospective noncomparative case series. PARTICIPANTS: Three patients ranging from 40 to 63 years of age with MCC participated. INTERVENTION: Excisional biopsies and various therapies were performed. MAIN OUTCOME MEASURES: Clinical and surgical outcomes were measured. RESULTS: Patient 1 is a 55-year-old man with right temporal MCC. He underwent two local excisions with adjuvant cryotherapy and has had no recurrence at 31 months follow-up. Patient 2 is a 63-year-old man with right temporal MCC who underwent fractionated iodine 125 plaque radiotherapy. He had a recurrence approximately 8 months after plaque treatment and subsequently underwent enucleation of the right eye. Clinical follow-up examinations revealed no further recurrence at 17 months. Patient 3 is a 40-year-old woman treated for right MCC with carbon dioxide laser with recurrence at 3 weeks. She subsequently underwent radiation treatment with the development of regional lymph node metastases 16 months later. CONCLUSIONS: MCC is a rare neoplasm that displays an extraordinary capacity for aggressive local invasion. This series of three case reports demonstrates the high recurrence rate of MCC and the response of this tumor to different current modalities of treatment. Extended follow-up is required with this tumor because distant metastases can occur very late.

Cavernous hemangiomas of the orbital apex with intracranial extension.

Cavernous hemangiomas are benign vascular tumors that usually present as unilateral, intraconal mass lesions in middle-aged women. They may on occasion extend to the orbital apex or have intracranial extension. The authors present three patients with deep apical hemangiomas, two of whom had intracranial extension to the cavernous sinus area.

A synthetic hydroxyapatite implant: the so-called counterfeit implant.

This article evaluates three generations of synthetic hydroxyapatite implants in a rabbit model. Fourteen New Zealand white rabbits received synthetic hydroxyapatite orbital implants (first, second, and third generation). The rabbits underwent enucleation of one eye and then received a 12-mm synthetic hydroxyapatite implant wrapped in Vicryl (polygalactin 910; Ethicon, Inc.) mesh or sclera. Magnetic resonance imaging was conducted to assess host fibrovascularization of the implant 4 and 12 weeks after implantation. Animals were killed at each of these times and the implant was removed for histopathologic examination. Enhancement on magnetic resonance imaging and extent of fibrovascularization by histopathologic examination were assessed. The first-generation synthetic hydroxyapatite (FCI, Issy-Les-Moulineaux, France) was not 100% hydroxyapatite as is the Bio Eye (Integrated Orbital Implants, Inc., San Diego, CA, U.S.A.). It contained 3.2% calcium oxide. The implant was heavier and much less porous than the original Bio Eye implant. Central vascularization eventually occurred but was not extensive. The second-generation implant was more porous than the first, with rapid central vascularization to the center of the implant by 4 weeks. However, the second-generation implant was very fragile and crumbled easily. The second-generation synthetic implant was chemically identical to the original Bio Eye implant with no calcium oxide. The third-generation implant was more porous than its predecessors. When compared side by side with the Bio Eye, a difference in pore uniformity and interconnectivity seems apparent. However, an early extensive vascularization pattern to the center of the implant is seen histopathologically, similar to that with the Bio Eye. Magnetic resonance imaging also shows extensive enhancement as is the case with the Bio Eye. The third-generation synthetic implant is not fragile as was the second-generation implant, and chemically it is identical to the Bio Eye with no calcium oxide present. The third-generation implant is approximately half the price of the original Bio Eye implant.

Use of temporalis fascia for exposed hydroxyapatite orbital implants.

The hydroxyapatite implant (Bio-Eye, Intergrated Orbital Implant, Inc., San Diego, CA, U.S.A.) has gained increasing popularity as an orbital implant in recent years. Several complications may occur, including infection, exposure, extrusion, and various peg problems. Exposure of the implant appears to be the most common complication, ranging up to 21.6%. Many techniques, including nonsurgical and surgical approaches, have been described to manage these exposures. When surgery is indicated, a patch graft may be required to cover the defect. We report our experience and technique with autogenous temporalis fascia as a patch graft. Autografts such as temporalis fascia are easily obtained, bring about no immunological reaction, and have no risk of infectious transmission.

Periocular necrotizing fasciitis: a review of five cases.

OBJECTIVE: The purpose of the study is to display a spectrum of clinical presentations of periocular necrotizing fasciitis caused by group A streptococci and to discuss recent trends and treatment of this disease. DESIGN AND INTERVENTION: A case series of five patients (four female and one male) was seen between July 1990 and January 1995 in four university centers. All had clinical evidence of periocular necrotizing fasciitis and grew group A streptococci on wound cultures or had serologic evidence of streptococcal infection. Details of patient presentation, treatment, and outcome are examined. RESULTS: The five patients showed a spectrum of clinical severity from a necrotizing infection confined to the eyelid to a potentially fatal, severe shock-like syndrome characterized by sepsis and multiorgan system failure. A history of trauma often was absent. Patients were treated successfully by a combination of appropriate antibiotics and surgical debridement. CONCLUSIONS: Group A streptococci can cause severe necrotizing infections of the eyelids. Early recognition and prompt treatment can be essential to these patients' survival.

Post-traumatic corneal mucormycosis caused by Absidia corymbifera.

OBJECTIVE: The purpose of the study was to report a case of mycotic keratitis caused by the organism Absidia corymbifera (class Zygomycetes, order Mucorales, family Mucoraceae). DESIGN: Case report. PARTICIPANT: A healthy 37-year-old farmer scratched his left cornea on a galvanized nail while working in his barn. Within 24 hours, an infiltrate in the interior cornea developed that advanced superiorly, reducing the vision to hand motion by the following day. He was treated with topical and systemic antibiotics and antifungal medications, but the infiltrate spread to the adjacent nasal limbus. INTERVENTION: An 11-mm penetrating keratoplasty was performed with an adjacent nasal 7-mm superficial lamellar sclerectomy. MAIN OUTCOME MEASURES: Pathologic examination of the keratoplasty specimen. RESULTS: Corneal cultures grew A. corymbifera. The organisms were identified in tissue sections by light, fluorescent, electron, and immunoelectron microscopy. CONCLUSIONS: The authors believe that this is the first reported case of keratitis caused by an Absidia species and, as such, represents an unusual form of mucormycosis in an otherwise healthy individual.

Orbital infections in patients with human immunodeficiency virus infection.

BACKGROUND: Opportunistic infections frequently involve the anterior and posterior segments of the eye but rarely occur in the orbit in patients with human immunodeficiency virus (HIV) infection. The authors managed eight patients with HIV and unilateral orbital infections who presented between July 1988 and March 1995. METHODS: Records of the patients were reviewed. A literature review of orbital infections in patients infected with HIV also was conducted. RESULTS: There were five men and three women, with a mean age of 33.8 years. The mean CD-4 cell count from five of the eight patients was 18.4 cells/mm3. Invasive aspergillosis was the most common orbital infection occurring in four patients, all of whom had contiguous sinus involvement and intracranial extension. Orbital cellulitis with subperiosteal abscesses secondary to ethmoiditis caused by Propionibacterium acnes and Pseudomonas aeruginosa developed in two patients. Orbital cellulitis and panophthalmitis secondary to Staphylococcus aureus endogenous endophthalmitis developed in one patient, and one patient had presumed syphilitic optic neuritis, orbital periostitis, and necrotizing vasculitis. Five patients had permanent visual loss, including four who had loss of light perception. Four patients died of orbital diseases within 1 year of presentation, and three deaths were attributed to intracranial spread of Aspergillus fumigatus. Other organisms reported in the literature that caused orbital infections in patients with HIV include Rhizopus arrhizus, Toxoplasma gondii, and Pneumocystis carinii. CONCLUSION: Opportunistic infections of the orbit from bacterial, fungal, and parasitic organisms should be recognized as a serious complication of systemic HIV infection and are associated with a high ocular morbidity and mortality rate.

Vicryl-mesh wrap for the implantation of hydroxyapatite orbital implants: an animal model.

OBJECTIVE: To evaluate host fibrovascularization of hydroxyapatite orbital implants wrapped in sclera or in Vicryl (polyglactin 910) mesh in a rabbit model. NUMBERS: Eight adult New Zealand white rabbits that received hydroxyapatite orbital implants wrapped in homologous donor sclera (four animals) or Vicryl mesh (four animals). INTERVENTIONS: The rabbits had one eye enucleated and then received a 12-mm hydroxyapatite implant wrapped in sclera or Vicryl mesh. Magnetic resonance imaging (MRI) and bone scintigraphy were done to assess host fibrovascularization of the implant 4, 8, 12 and 20 weeks after implantation. Two animals (one in each group) were killed at each of these times, and the implant was removed for histopathological examination. MAIN OUTCOME MEASURES: Enhancement on MRI, uptake on bone scintigraphy, fibrovascularization seen on histopathological examination. RESULTS: The degree of fibrovascularization was substantial in all the specimens but appeared greater in the Vicryl-mesh-wrapped implants in the first 12 weeks after implantation on both histopathological and MRI studies. At 20 weeks these findings were similar in the two groups. A granulomatous foreign-body giant-cell reaction to both the Vicryl mesh and the implant itself was present up to 8 weeks after implantation. Bone scans showed only grade 1+ activity in all the implants. CONCLUSIONS: Host fibrovascularization in the rabbit appears to occur to a greater degree in Vicryl-mesh-wrapped hydroxyapatite implants than in those wrapped in donor sclera during the first 12 weeks after implantation. Vicryl mesh appears to be an acceptable alternative wrap for the hydroxyapatite implant, eliminating the need for donor sclera and its potential risks of transmissible diseases.