Hydroxyapatite orbital implant abscess: histopathologic correlation of an infected implant following evisceration

A 60-year-old diabetic man with a history of ocular trauma and absolute glaucoma underwent evisceration with placement of an 18 mm hydroxyapatite orbital implant. The host scleral shell was left intact with no posterior opening for vascular ingrowth. One year later the patient presented with implant exposure, limited fibrovascular ingrowth into the implant, and a Staphylococcus aureus orbital abscess. The implant was removed, and pathology demonstrated suppurative inflammation with limited vascular ingrowth. This patient's risk factors for an implant-associated wound infection included diabetes, impaired wound healing, history of trauma, early implant exposure, and delayed fibrovascular ingrowth. Awareness of the infectious complications of any orbital implant including hydroxyapatite allows the surgeon to alter management strategies in an attempt to reduce such risk. Surgeons may consider posterior scleral portals with evisceration surgery to facilitate hydroxyapatite vascularization. Patient selection, implant size, and surgical technique are key factors for a management strategy designed to reduce the risk of implant infection.