Thereafter, the principal investigator entered the intervention section, opened and checked the sealed envelope. And he prepared the sacrococcygeal area using an iodine-based povidone and an alcohol swabs. As a topical pre-CEI anesthesia, the marked site was infiltrated subcutaneously with 3 ml of 2% lidocaine in the local infiltration group. In the spray group, the marked site was sprayed using an vapocoolant spray (Walter Ritter GmbH and Co., Hamburg, Germany) for 10-sec from a distance of 30 cm. To enhance a blind design, 10-sec spray was performed with targeting to the open air after 3 min (time for manifesting the effect of lidocaine) in the local infiltration group. In the spray group, there had been same time interval of 3 min before spraying.