This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: ENT
Schwartz operation is also called as - 
Select and explain. 
A. Cortical mastoidectomy, B. Modified radical mastoidectomy, C. Radical mastoidectomy, D. Fenestration operation
A: Cortical mastoidectomy
Answer: A: Cortical mastoidectomy 
Explanation: Mastoidectomy is defined as a surgical procedure which opens up the mastoid cavity, cleans up the infected air cells, improves middle ear ventilation by widening of the aditus.
There are several types of mastoidectomy.

Cortical mastoidectomy (simple mastoidectomy or schwartz operation)

The mastoid air-cell system is exenterated, including epitympanum.
But the posterior meatal wall (canal wall) is left intact.