An Orbital Mystery: A Unique Case of an Obsolete Orbital Implant With a Review of Orbital Implant Materials

Abstract

Orbital implant materials have evolved greatly over the past century and include but are not limited to metal, ceramic, polymer, silicone, and glass. Knowledge of historically used materials is clinically relevant to patient care as certain materials carry a greater risk of migration, extrusion, infection, and limitations for imaging modalities utilized to visualize adjacent structures.We report an unusual case of an 80-year-old male who presented to our community hospital with seizurelike activity. CT imaging of the brain revealed several white matter and cortex lesions with the largest lesion measuring 2.5 × 2 × 1.9 cm. The patient had a history of enucleation with placement of an orbital implant following a penetrating injury to the left eye at four years of age. Hounsfield scale analysis was read by radiology as being most consistent with a thin metallic shell surrounding the orbital implant. The potential for metallic material was consistent with the implant's age and time of placement. Few reviews on ocular implant materials from this period exist in the current medical literature. A single case report discussing a hollow metal orbital implant with similar-appearing imaging was identified. Due to concern for possible metal implant materials, the patient underwent implant exchange so MRI imaging could safely be performed. Intraoperatively, the implant was identified as a clear, hollow, non-metallic, non-porous polymer sphere. Following surgery, the patient was able to undergo appropriate neuroimaging with subsequent diagnostic biopsy.Current literature reviewing CT or photographic imaging of ocular implant devices prior to the 1940s is limited. This case highlights the importance of detailing materials historically used in orbital implants, their effects on clinical decision-making, and the utility of Hounsfield scale values to identify a material's radiodensity on CT imaging.