A 5-year-old child with bilateral profound sensorineural hearing loss from connexin-26 mutation is evaluated for cochlear implantation. Which finding on preoperative high-resolution CT temporal bone would most likely alter the surgical approach?

• A Incomplete partition type II (Mondini deformity)
• B Cochlear nerve aplasia on MRI ✓
• C Enlarged vestibular aqueduct alone
• D Narrow cochlear aperture less than 1.4 mm

Explanation

Cochlear nerve aplasia (absent cochlear nerve on MRI) is an absolute contraindication to standard cochlear implantation because the auditory nerve is the relay for electrical stimulation. In such cases, auditory brainstem implantation (ABI) may be considered instead. Narrow cochlear aperture below 1.4 mm is a relative concern (risks gusher), Mondini deformity and enlarged vestibular aqueduct require modified technique but are not absolute contraindications. CT cannot reliably visualize the cochlear nerve, hence MRI is essential.

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.