Piece of furniture for surgeon's assistant (7)
I believe the answer is:
dresser
This clue is a triple definition!
'piece' is the first definition.
(I have seen 'Piece of furniture ' mean 'dresser' so perhaps 'piece' could also mean 'dresser')
'of' is a link.
'furniture' is the second definition.
(dresser is a kind of furniture)
'for' is a link.
'surgeon's assistant' is the third definition.
(I've seen this before)
(Other definitions for dresser that I've seen before include "Cabinet with shelves" , "Item of furniture - actor's assistant" , "Wardrobe assistant" , "What Hardy Amies would do once" , "Tool for smoothing" .)