At the same time of basic treatment , the electroacupuncture was applied at Changqiang ( GV 1 ) and Chengshan ( BL 57 ) 30 min before surgery in the electroacupuncture group , while shallow needling without electrical stimulation at sham acupoint ( 1 cm next to acupoint ) was applied 30 min before surgery in the sham electroacupuncture group , while no treatment was given before the surgery in the blank group .