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RESUMEN

This report illustrates the successful removal of a proper intra-orbital oculosporidiosis (extralacrimal, extraconjunctival) exclusively by the endonasal endoscopic approach. It also introduces the naso-orbital pseudofontanelle as an important surgical landmark and describes a hitherto undefined intra-orbital extramucosal three-dimensional potential wedge that harbored the Rhinosporidium seeberi infestation as a nodular conglomerate. The patient, a 50-year-old woman, was operated on three years ago for rhinosporidiosis of the nasal cavity and the distal lacrimal drainage system (lacrimal sac and nasolacrimal duct). The resulting alterations in regional anatomy were evident on imaging. They could explain the present recurrence and formation of the pseudofontanelle that allowed the conglomerate to bulge through the lateral nasal wall on digital pressure, making endoscopic intervention feasible. The primary principle for adopting this approach was to protect the facial skin from possible seeding. With an angled endoscope, the pseudofontanelle was breached and the intra-orbital extramucosal wedge between the bony orbital wall and the peri-orbita entered. The nodules that formed the conglomerate were densely adherent with the peri-orbita and skin. They were carefully and meticulously removed to avoid inadvertent injury to vital intra-orbital structures. Endonasal endoscopic intervention for a true intra-orbital oculosporidiosis has never been documented before. The surgical approach, the newly defined anatomical domain for the intra-orbital extramucosal oculosporidiosis, and the concept of pseudofontanelle characterize this report as a novel clinical experience worth presenting.

RESUMEN

Trabecular bone is a lightweight, compliant material organized as a web of struts and rods (trabeculae) that erode with age and the onset of bone diseases like osteoporosis, leading to increased fracture risk. The traditional diagnostic marker of osteoporosis, bone mineral density (BMD), has been shown in ex vivo experiments to correlate poorly with fracture resistance when considered on its own, while structural features in conjunction with BMD can explain more of the variation in trabecular bone strength. We develop a network-based model of trabecular bone by creating graphs from micro-computed tomography images of human bone, with weighted links representing trabeculae and nodes representing branch points. These graphs enable calculation of quantitative network metrics to characterize trabecular structure. We also create finite element models of the networks in which each link is represented by a beam, facilitating analysis of the mechanical response of the bone samples to simulated loading. We examine the structural and mechanical properties of trabecular bone at the scale of individual trabeculae (of order 0.1 mm) and at the scale of selected volumes of interest (approximately a few mm), referred to as VOIs. At the VOI scale, we find significant correlations between the stiffness of VOIs and 10 different structural metrics. Individually, the volume fraction of each VOI is most strongly correlated to the stiffness of the VOI. We use multiple linear regression to identify the smallest subset of variables needed to capture the variation in stiffness. In a linear fit, we find that node degree, weighted node degree, Z-orientation, weighted Z-orientation, trabecular spacing, link length, and the number of links are the structural metrics that are most significant (p<0.05) in capturing the variation of stiffness in trabecular networks.

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