**Question:** Endolymphatic decompression is done in:

Core Concept: Endolymphatic decompression is a surgical procedure that aims to relieve pressure in the inner ear and treat vestibular disorders caused by an obstructed or dilated endolymphatic duct or sac.

Correct Answer: C. Endolymphatic decompression is primarily done in the middle ear, as part of the endolymphatic sac decompression surgery (also known as Schuknecht's procedure).

Why the Correct Answer is Right: Endolymphatic sac decompression is a surgical technique used to alleviate pressure within the inner ear, particularly in cases of Ménière's disease, which is characterized by vertigo, fluctuating hearing loss, tinnitus, and aural fullness. By decompressing the endolymphatic sac, surgeons aim to reduce the volume of endolymph and improve drainage from the inner ear, thereby alleviating symptoms.

Why Each Wrong Option is Incorrect:

A. Endolymphatic hydrops (an excessive accumulation of endolymph) is a key feature of Ménière's disease; however, decompressing the endolymphatic duct (Option A) is not the primary target of the procedure.

B. Although some patients may benefit from decompression of the vestibular aqueduct (Option B), the primary goal is decompressing the endolymphatic sac (option C), not the aqueduct itself.

D. Although vestibular neurectomy (Option D) is a surgical procedure performed in the context of Ménière's disease, decompressing the vestibular nerve is not the main objective of endolymphatic sac decompression.

Clinical Pearl: In Ménière's disease, endolymphatic decompression aims to treat the underlying pathophysiology of endolymphatic hydrops, rather than directly targeting specific structures like the duct, sac, aqueduct, or nerve.

**Correct Answer: C. Endolymphatic sac decompression**

Endolymphatic decompression surgery involves accessing the endolymphatic sac through the mastoid cell, in the middle ear. By decompressing the endolymphatic sac, surgeons can reduce the volume of endolymph and improve the drainage of the inner ear, alleviating symptoms in patients with Ménière's disease or other hydrops-related disorders.