Patients were assigned to one of four groups : SI patients received SNB using short-axis ( SA ) view of the SN and in-plane ( IP ) placement of block needle ( SA-IP approach ) ; LI patients received SNB using long-axis ( LA ) view of the SN and IP needle placement ( LA-IP approach ) ; SO patients received the block using SA view of the SN and out-of-plane ( OP ) needle placement ( SA-OP approach ) ; LO patients received SNB using LA view of the SN and OP needle placement ( LA-OP ) .