A patient develops clear watery discharge from the nose following endoscopic sinus surgery. The fluid is sent for beta-2 transferrin testing which is positive. What is the most common site of iatrogenic CSF leak during endoscopic sinus surgery?

• A Cribriform plate of the ethmoid
• B Roof of the sphenoid sinus
• C Posterior wall of the frontal sinus
• D Lateral lamella of the cribriform plate ✓

Explanation

The lateral lamella of the cribriform plate is the thinnest and most vulnerable area of the anterior cranial fossa, making it the most common site of iatrogenic CSF leak during FESS. Its thickness can be as little as 0.2 mm. Injury occurs when dissection extends too superiorly in the ethmoid region. The Keros classification describes the depth of the olfactory fossa in this region.

Reference: Cummings Otolaryngology: Head and Neck Surgery, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.