Background: Intussusception is the most common abdominal emergency in children. The first line treatment of uncomplicated pediatric intussusception is enema reduction. Until now, there have been no multi-center studies comparing the effectiveness and safety of UGHR and FGAR in the treatment of pediatric intussusception. The aim of this study was to compare the effectiveness and safety of the two most commonly used enema methods of pediatric intussusception: ultrasound-guided hydrostatic reduction (UGHR) and fluoroscopy-guided air reduction (FGAR). Methods: From November 1, 2017 to October 31, 2018, we conducted a multi-center, prospective, cohort study. Children diagnosed with intussusception in four large Children’s Medical Centers in China were divided into UGHR and FGAR groups. Stratified analysis and subgroup analysis were used for further comparison. The success and recurrence rates were used to evaluate the effectiveness of enema reduction. The perforation rate was used to evaluate the safety of enema reduction. Results: A total of 2124 cases met the inclusion criteria (UGHR group: 1119 cases; FGAR group: 1005 cases). The success and recurrence rates in the UGHR group were higher than in the FGAR group (95.80%, 9.28% vs. 93.13%, 10.65%) (P < 0.05, P > 0.05), respectively. The perforation rate in the UGHR group was 0.36% compared with 0.30% in the FGAR group (P > 0.05). Subgroup analysis showed the success rates in the UGHR group were higher than in the FGAR group of patients with onset time between 12 and 24 h (95.56% vs. 90.57%) (P < 0.05). Of patients aged 4 to 24 months, the success rates in the UGHR group were also higher than in the FGAR group (95.77% vs. 91.60%) (P < 0.05). Stratified analysis showed the success rates in the UGHR group were higher than in the FGAR group in patients with the symptom of bloody stool (91.91% vs 85.38%) (P < 0.05). Conclusions: UGHR and FGAR are safe, nonsurgical treatment methods for acute pediatric intussusception. UGHR is superior to FGAR, no radiation risk, its success rate is higher, without a difference in perforation rate, especially for patients aged 4–24 months. Level of evidence: Level II.

Purpose: The aim of this study was to determine the expression of Cdx4 (caudal-type homeobox gene-4) during anorectal development in normal and ethylenethiourea (ETU)-induced anorectal malformation (ARM) embryos with a view to establishing the possible role of Cdx4 in ARM pathogenesis. Materials and Methods: ARM was induced by ETU on the 10th gestational day (GD10) in rat embryos. Cesarean deliveries were then performed to harvest the embryos. Spatiotemporal expression of Cdx4 was evaluated in normal rat embryos (n = 354) and ARM embryos (n = 378) from GD13 to GD16. Results: Immunohistochemical staining and immunofluorescence revealed that, in normal embryos, Cdx4 expression was extensively detected on the epithelium of the cloaca on GD13. On GD14, the Cdx4-positive cells were intensively detected on the hindgut. On GD15, the anal membrane was constantly immunoreactive to Cdx4. On GD16, Cdx4-labeled cells were observed on the epithelium of the anus. In the ARM embryos, the epithelium of the cloaca, urorectal septum (URS) and anorectum was negative or faint for Cdx4. In the normal embryo group, Cdx4 protein and mRNA expression showed time-dependent changes in the developing hindgut from GD13 to GD16 on Western blot and real-time reverse transcription plus polymerase chain reaction. Once the URS divided the cloaca into the primitive rectum and urogenital sinus (UGS) on GD15, Cdx4 expression began to decrease. In addition, the expression level of Cdx4 in the ARM group from GD13 to GD15 was significantly lower than that in the normal group (p < 0.05). Conclusions: In ARM embryos, an imbalance in the spatiotemporal expression of Cdx4 was noted during anorectal morphogenesis from GD13 to GD16. This suggests that ETU may cause downregulation of Cdx4 expression. Downregulation of Cdx4 at the time of cloacal separation into the primitive rectum and UGS might thus be related to the development of ARM.