Background: The microdebrider has become nearly universal in the treatment of sinonasal pathology; however, recent case reports have demonstrated the potential for major ophthalmic complications. The goal of this study was twofold: 1) determine the anatomical proximity of ophthalmic structures to the paranasal sinuses, and 2) assess the timeframe at which ophthalmic injury may occur with the use of a microdebrider during FESS utilizing a cadaveric model. Methodology/Principal: Computed tomography scans from 50 patients were accessed retrospectively. The distances between the lamina papyracea (LP) and orbital structures were determined at varying depths. Seven cadavers (14 sides) were studied using three microdebrider systems operated by otolaryngology residents. Following removal of a window of LP, the time from activation of the microdebrider on the periorbita until transection of the medial rectus (MR), optic nerve (ON), and to aspiration of the globe were measured. Results: The mean distance between the LP and MR at the level of the anterior aspect of the anterior ethmoid and basal lamella were 3.59 ±1.2mm and 1.5 ±0.8mm, respectively. The mean distance between the LP and ON at the level of the basal lamella was 8.1 ±2.1mm. Mean transection times for the MR and ON were 13.4 ± 7.3 seconds and 37.3 ± 9.2 seconds, respectively, with minimum times of 4 seconds and 26 seconds. Conclusions: The proximity of orbital structures to the paranasal sinuses and the rapidity of ophthalmic damage following violation of the periorbita reaffirms the need for cautious use of the microdebrider during FESS.

Background Extramedullary hematopoiesis (EMH) occurs in patients with hematologic disorders, but rarely within the paranasal sinuses. We report a case of EMH in a 17-year-old male with sickle cell disease (SCD) who presented with occipital pain and sinusitis. A computed tomography (CT) scan demonstrated heterogeneous opacification of the right maxillary sinus concerning for allergic fungal sinusitis or a fungal ball with bony erosion. He was taken to the operating room for endoscopic biopsy and a limited endoscopic sinus surgery. Grossly, his maxillary sinus was filled with spiculated osseous tissue. Final pathology demonstrated active hematopoietic bone marrow filling the sinus. Methods We present a case report and literature review of sinonasal EMH. Results We identified 14 articles with 15 patients. EMH was typically associated with SCD or beta thalassemia. The average age of presentation was 30. There was a male sex predilection with a ratio of 11:15. The most common presenting symptom was a headache and nasal obstruction (33% for both). The most common finding on CT was a soft tissue expansile mass (73%). The most commonly affected location was the maxillary sinus (60%). Conclusions This case report serves as a reminder to consider EMH as an uncommon cause of sinus opacification, particularly in patients with SCD or beta thalassemia. The expansion of hematopoietic tissue may be identified as a sinus mass on CT. By recognizing the potential manifestations of chronic anemia, an accurate and timely diagnosis can be made.

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