Group Rop ( n = 40 ) received pre and post-incisional infiltration with 150 mg of ropivacaine in 8 mL of 0.9 % saline , while group Rop/Dx ( n = 40 ) received 150 mg of ropivacaine with 8 mg of dexamethasone in 6 mL of 0.9 % saline .