A patient with cochlear otosclerosis develops profound SNHL. A cochlear implant is planned. Which finding on preoperative CT would indicate the need for a split electrode array or alternative surgical approach due to risk of facial nerve stimulation?

• A Dehiscence of the facial nerve at the geniculate ganglion
• B Ossification of the basal turn of the cochlea
• C Severe otic capsule demineralization with patent cochlear lumen ✓
• D Enlarged vestibular aqueduct

Explanation

In cochlear otosclerosis, severe otic capsule demineralization lowers impedance between the electrode array and the facial nerve, causing unwanted facial nerve stimulation (twitching) at high current levels. This occurs because the demineralized bone no longer insulates the current. Split electrodes or alternative programming may be needed. Basal turn ossification requires a compressed array instead.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.