id	keyword
gra-1921	block
gra-1921	clonidine
gra-1921	ropivacaine
gra-1921	study
gra-1921	group
gra-1921	duration
gra-1921	levobupivacaine
gra-1921	plexus
gra-1921	analgesia
gra-1921	anaesthesia