Functional Endoscopic Sinus Surgery (FESS) — Indications and Modern Techniques

Functional endoscopic sinus surgery (FESS) is a minimally invasive surgical approach for chronic rhinosinusitis (CRS) and other sinonasal pathologies, performed entirely through the nasal cavity using rigid endoscopes (typically 0°, 30°, 45°, and 70° angles) for direct visualization of the paranasal sinus anatomy and pathology. The procedure restores ventilation and mucociliary clearance of the sinuses by enlarging natural drainage pathways while preserving normal mucosa whenever possible.

Common procedures performed during FESS include uncinectomy (removal of the uncinate process), maxillary antrostomy (enlargement of the maxillary ostium), ethmoidectomy (anterior and posterior ethmoid cell removal), sphenoidotomy (sphenoid sinus opening), and frontal sinusotomy (frontal recess opening, ranging from Draf I to Draf III/modified Lothrop procedure). The extent of dissection is determined by disease distribution as documented by preoperative CT imaging and intraoperative findings, with goal of achieving maximal disease clearance while preserving healthy structures.

Patient selection follows rigorous criteria established by international guidelines (EPOS 2020, ICAR-RS 2021): primary indications include CRS refractory to maximal medical therapy (typically 8-12 weeks of nasal saline irrigation, intranasal corticosteroids, oral antibiotics, and sometimes oral steroids), CRS with nasal polyps not responsive to medical management, recurrent acute rhinosinusitis (≥4 episodes per year despite optimization), complications of acute rhinosinusitis (orbital, intracranial), invasive fungal sinusitis, and selected sinonasal tumors. Modern advances include image-guided navigation systems for complex cases, balloon sinuplasty as standalone procedure or hybrid technique, integrated biologic therapy for type 2 inflammatory phenotypes (dupilumab particularly transformative for CRSwNP), and evolving techniques for inverted papilloma, mucoceles, and skull base lesions through endoscopic transnasal approaches.