A 4-year-old boy who recovered from pneumococcal meningitis is found to have bilateral profound sensorineural hearing loss confirmed by brainstem evoked response audiometry. His parents are counselled regarding cochlear implantation. The reason implantation should proceed early rather than being deferred for a year is:
- A Implantation must precede maturation of the facial nerve canal
- B Delay increases the risk of cholesteatoma formation in the middle ear
- C Post-meningitic fibrosis and new bone formation obliterate the scala tympani, making later electrode insertion difficult ✓
- D Electrode impedance falls progressively if surgery is done early
Correct answer: C. Post-meningitic fibrosis and new bone formation obliterate the scala tympani, making later electrode insertion difficult
Explanation
Meningogenic deafness is complicated by labyrinthitis ossificans, in which fibrous tissue followed by new bone fills the cochlear lumen, beginning in the basal turn of the scala tympani. Once ossification is established, electrode insertion may require drill-out of the basal turn, with higher trauma and poorer audiological outcome. Early imaging and implantation, ideally within weeks to a few months, secure access to a patent scala tympani.
Reference: Cummings Otolaryngology Head and Neck Surgery, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.