I wish I could manage without small medical instrument! (8)
I believe the answer is:
otoscope
'medical instrument' is the definition.
(otoscope is a kind of medical instrument)
'i wish i could manage without small' is the wordplay.
'i wish i could' becomes 'oto' (I can't explain this - if you can you should believe this answer much more).
'manage' becomes 'cope' (manage can mean to cope or do well).
'without' means one lot of letters goes inside another ('without' can be similar in meaning to 'outside').
'small' becomes 's' (abbreviation - e.g. clothes size).
'oto'+'cope'='otocope'
'otocope' going around 's' is 'OTOSCOPE'.
Can you help me to learn more?
(Other definitions for otoscope that I've seen before include "It's used to examine 27 ac" , "Instrument for visual examination of an ear" , "probe" , "Lug instrument" , "instrument coming close to a canal" .)