neurosurgeon vs brain surgeon

neurosurgeon and brain surgeon both are nouns.

Word	Noun	Adjective	Verb	Adverb
neurosurgeon	Yes	No	No	No
brain surgeon	Yes	No	No	No

As nouns, neurosurgeon and brain surgeon are synonyms defined as:

neurosurgeon and brain surgeon: someone who does surgery on the nervous system (especially the brain)

neurosurgeon (noun)	brain surgeon (noun)
someone who does surgery on the nervous system (especially the brain)	someone who does surgery on the nervous system (especially the brain)