Background:Intraoperative neuromuscular blocker is widely used, but is known to be associated with postoperative residual paralysis, which is known to be associated with increased risk of pulmonary complications. Hence, its use should be individualized and restricted to procedures where it is mandatory. We examined whether not using a neuromuscular blocker affects the surgical conditions in children undergoing inguinal herniorrhaphy.Methods:Anesthesia was induced and maintained with sevoflurane in 60% nitrous oxide, and the airway was maintained using an I-gel. In total, 66 children aged 1 to 6 years were randomized to receive rocuronium (rocuronium group, n = 33) or saline (control group, n = 33); 61 children of them finished the study. A single surgeon who performed the operation rated the surgical condition of each patient on a 4-point scale (1 = poor, 2 = acceptable, 3 = good, and 4 = excellent). Intraoperative patient movement, recovery time, emergence agitation, and postoperative pain scores were evaluated.Results:One patient in control group and no patient in rocuronium group showed intraoperative movement. When noninferiority test was done for intraoperative patient movement, with the noninferiority margin of 20%, the difference of absolute risk was 3.3% (95% confidence interval −8.0% to 16.7%) and saline group was noninferior to rocuronium group. All of the patients showed good to excellent surgical conditions, and no difference was found between the 2 groups. The recovery time was shorter in the control group than in the rocuronium group (4.5 ± 1.8 vs 5.6 ± 2.2 minutes, respectively; P = .028).Conclusion:In children aged 1 to 6 years undergoing inguinal herniorhaphy under sevoflurane anesthesia using an I-gel, not using neuromuscular blocker showed similar intraoperative condition and shortened recovery time compared with using neuromouscular blocker.