Ultrasound-guided sacral multifidus plane block versus caudal epidural block for postoperative analgesia in pediatric hypospadias surgery: A randomized double-blind controlled trial - Amr Sobhy; Radwa Tarek Mohamed; Gihan seif; Manal mohamed kamal shams; Adham Magdy Haggag; Abd El-Aziz A. Abd EL-Aziz (PLoS ONE, 2026)