Son has spine endlessly rotated as part of the healing process (4)
I believe the answer is:
scab
'part of the healing process' is the definition.
(I've seen this in another clue)
'son has spine endlessly rotated' is the wordplay.
I cannot quite see how this works, but
'son' could be 's' (genealogical abbreviation for son) and 's' is found within the answer.
The remaining letters 'cab' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'as' is the link.
(Other definitions for scab that I've seen before include "Scoundrel" , "Dried surface of wound" , "Disease of sheep" , "despicable person" , "Strike-breaker; skin disease in animals" .)