Which of the following is a common etiology of sensorineural hearing loss in neurosurgical patients?

• A. Otitis media
• B. Otosclerosis
• C. CN VIII injury
• D. Eustachian tube dysfunction

Answer: (C)

In this context, sensorineural hearing loss in neurosurgical patients most often comes from injury to the eighth cranial nerve. The vestibulocochlear nerve travels near the skull base and cerebellopontine angle, exactly where many neurosurgical procedures occur. Manipulation, drilling, or tumor removal in this area can directly affect the cochlear portion of CN VIII, leading to unilateral or bilateral sensorineural loss, sometimes with tinnitus or vertigo depending on the extent.

Other options cause conductive hearing loss rather than sensorineural. Otitis media involves infection or fluid in the middle ear, which impedes the eardrum and ossicles. Otosclerosis fixes the stapes, reducing its movement and affecting sound transmission in the middle ear. Eustachian tube dysfunction affects pressure and fluid in the middle ear as well, also leading to conductive loss.