Simple duties can vary with this, including surgery (15)
I believe the answer is:
unsophisticated
'simple' is the definition.
(similar in meaning)
'duties can vary with this including surgery' is the wordplay.
'vary with' indicates an anagram.
'including' means one lot of letters goes inside another.
'surgery' becomes 'op' (short for operation).
'duties'+'can'='dutiescan'
'dutiescan' anagrammed with 'this' can make 'unshisticated'.
'unshisticated' placed around 'op' is 'UNSOPHISTICATED'.
(Other definitions for unsophisticated that I've seen before include "Simple" , "green" , "Lacking experience" , "straightforward" , "crude" .)