The most common and most likely answer to this crossword clue is the 12 letter word EXTERIORISED
I've seen this crossword clue in The Times
E
X
T
E
R
I
O
R
I
S
E
D
Buddy explains!
The straight part
We know that "brought out in surgery" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case brought out in surgery = exteriorised.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does EXTERIORISED mean?
EXTERIORISED verb- To externalize.
- To expose (an internal organ) for observation or surgery.