During stapedectomy for otosclerosis, the surgeon encounters a perilymph 'gusher' — a forceful flow of perilymph from the oval window after stapedotomy. The most likely underlying abnormality causing this complication is:

• A X-linked mixed deafness (DFNX2) due to POU3F4 (BRN4) mutation — widened cochlear aqueduct or cochlear malformation with patent fundus of IAC communicating with CSF ✓
• B Rupture of the round window membrane during surgery
• C Aberrant internal carotid artery in the middle ear
• D Superior canal dehiscence syndrome with low CSF pressure

Explanation

Perilymph gusher during stapedotomy is a rare but serious complication associated with X-linked mixed deafness (DFN3, DFNX2), caused by POU3F4 (BRN4) mutations. This condition features a widely patent fundus of the internal auditory canal communicating with the cochlea, and a widened or anomalous cochlear aqueduct, resulting in direct communication between the subarachnoid CSF space and the perilymph. When the stapes is removed, CSF-perilymph mixture gushes through the oval window. The gusher must be sealed immediately with fat/tissue to prevent meningitis. Pre-operative high-resolution CT should identify the IAC abnormality, and X-linked deafness should be suspected in males with bilateral 'otosclerosis' and absent oval window reflex.

Reference: Dhingra Diseases of Ear, Nose and Throat, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.