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Functional Endoscopic Sinus Surgery (FESS) is a minimally invasive surgical technique used to restore normal drainage and ventilation of the paranasal sinuses.
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| Category | Examples |
|---|---|
| Chronic rhinosinusitis (CRS) | With or without nasal polyps; refractory to medical therapy |
| Recurrent acute sinusitis | ≥4 episodes/year despite treatment |
| Sinonasal polyposis | Obstructing vision, airway, or causing anosmia |
| Mucoceles | Particularly in ethmoid or frontal sinuses |
| Fungal sinusitis | Allergic fungal rhinosinusitis, mycetoma |
| Sinonasal tumors | Benign: inverted papilloma; Malignant: biopsy or resection aid |
| Orbital decompression | For Graves’ orbitopathy or orbital cellulitis drainage |
| CSF rhinorrhea | Localization and repair of leak site |
| Structure | Relevance |
|---|---|
| Ostiomeatal complex (OMC) | Common drainage pathway for frontal, maxillary, and anterior ethmoid sinuses |
| Uncinate process | Removal opens access to maxillary sinus |
| Ethmoid bulla | Largest ethmoidal air cell; posterior border of OMC |
| Lamina papyracea | Thin medial orbital wall; risk of orbital injury |
| Cribriform plate (fovea ethmoidalis) | Roof of ethmoid sinus; injury risk → CSF leak |
| Sphenoid sinus ostium | Near vital structures: optic nerve, internal carotid artery |
| Agger nasi cells | Anterior to middle turbinate; key to frontal recess ventilation |