FUNCTIONAL ENDOSCOPIC SINUS SURGERY (FESS)

1. DEFINITION

2. HISTORICAL BACKGROUND

• Hopkins rod-lens telescope (1959) — enabled high-resolution endoscopic visualization
• Messerklinger (1978) — published the endoscopic atlas of nasal anatomy; described the concept of mucociliary clearance failure originating at the ostiomeatal complex (OMC)
• Stammberger & Kennedy (1985) — popularized FESS in the West
• The technique replaced older, disfiguring procedures (Caldwell–Luc, external ethmoidectomy)

3. CONCEPT: OSTIOMEATAL COMPLEX (OMC)

• Uncinate process
• Ethmoidal infundibulum
• Hiatus semilunaris
• Middle turbinate
• Ostia of maxillary, frontal, and anterior ethmoidal sinuses

Pathological principle: Disease/obstruction at the OMC → impaired mucociliary drainage → stasis → recurrent/chronic sinusitis. FESS targets and corrects this obstruction.

4. INDICATIONS

5. PRE-OPERATIVE EVALUATION

• CT scan of PNS (coronal + axial) — mandatory before FESS
  • Confirms extent of disease
  • Shows bony anatomy: level of cribriform plate, symmetry of skull base, integrity of lamina papyracea, Onodi cells
  • Review of Keros classification (depth of olfactory fossa) — determines risk of skull base injury
• Nasal endoscopy — assess nasal anatomy, polyp grade, discharge
• Medical optimization — systemic/topical steroids pre-operatively to reduce polyp bulk and bleeding

6. INSTRUMENTS USED

• 0° and 30° Hopkins rod-lens telescope (4 mm, 2.7 mm in pediatric)
• Light source + camera + monitor
• Freer's elevator / Ball probe
• Blakesley forceps (straight and angled)
• Backbiting forceps (for uncinate process)
• Kerrison rongeur
• Powered microdebrider — for nasal polypectomy; reduces bleeding, preserves mucosa
• Suction–irrigation system
• Navigation system (image-guided surgery) — in revision/complex cases

7. SURGICAL TECHNIQUE (Messerklinger Approach — Anterior to Posterior)

1. Patient positioned supine, head-end elevated 15–20°; general or local anesthesia with vasoconstrictor-soaked pledgets (4% xylocaine + 1:1000 adrenaline)
2. Uncinectomy — removal of uncinate process to open ethmoidal infundibulum
3. Middle meatal antrostomy (MMA) — enlargement of maxillary sinus ostium
4. Anterior ethmoidectomy — removal of anterior ethmoidal cells (bulla ethmoidalis)
5. Posterior ethmoidectomy — if disease involves posterior ethmoid cells
6. Sphenoidotomy — opening of sphenoid sinus ostium (if involved)
7. Frontal sinusotomy (Draf I/IIA/IIB/III) — if frontal sinus is diseased
8. Nasal polypectomy with microdebrider (if polyps present)
9. Hemostasis and nasal packing

Principle: Only diseased tissue is removed; normal mucosa is preserved to allow re-mucosalization.

8. POST-OPERATIVE CARE

• Nasal saline irrigation (douching) — promotes mucociliary clearance and prevents crusting
• Topical corticosteroid sprays — to prevent polyp recurrence
• Antibiotics — to prevent surgical site infection
• Regular follow-up endoscopy — to debride crusts, adhesions; ensure patency
• Avoid NSAIDs / aspirin — minimize bleeding risk

9. COMPLICATIONS

Minor (up to 5.7%)

• Epistaxis (most common)
• Adhesions / synechiae
• Crusting and infection
• Lamina papyracea dehiscence → periorbital ecchymosis / subcutaneous emphysema

Major (up to 1.5%)

10. ADVANTAGES OVER CONVENTIONAL SURGERY

SUMMARY (For Quick Recall)

Key exam points: OMC concept, mandatory CT PNS pre-op, uncinectomy as first step, CSF leak and orbital haematoma as major complications, and microdebrider for polypectomy.