What are the causes of pediatric hydronephrosis? The causes of pediatric hydronephrosis are complex, mostly congenital factors, including obstructive and non-obstructive hydronephrosis. The common causes of obstructive hydronephrosis are ureteropelvic junction stenosis or obstruction, uretero-vesical junction obstruction, ureteral cyst, neurogenic bladder, posterior urethral valve, urethral atresia and ectopic ureter, etc. The causes of non-obstructive hydronephrosis include primary vesicoureteral reflux, physiological pelvic calyces dilatation and Megan’s belly syndrome. Do all pediatric hydronephrosis require treatment? Mild hydronephrosis with no obvious symptoms can be followed up and observed, while moderate to severe hydronephrosis or symptomatic hydronephrosis requires a comprehensive analysis by a professional pediatric surgeon to make treatment choices. What types of pediatric hydronephrosis require surgical treatment? Hydrocele with clear evidence of obstruction or progressive kidney damage requires surgical treatment, consult a professional pediatric surgeon to make a choice. It is said that the best time for surgery is after 5 years of age. Is this true? This approach is wrong. Whether and when to operate needs to be based on the specific condition, and some children with etiologies such as posterior urethral valves even need to be treated during pregnancy in the fetal period. Does surgery for hydronephrosis necessarily involve kidney amputation? No. Generally, surgery is performed to remove the cause of obstruction, but only in cases of hydronephrosis where the kidney is severely atrophied, has lost function, or is combined with severe infection will the physician consider recommending removal of the kidney. Will the surgery affect the kidney function in the future? Successful surgery will generally prevent the kidney function from continuing to diminish, i.e. the surgery is considered successful if the kidney function is not aggravated after surgery. What are the main surgeries for pediatric hydronephrosis? Stenosis resection, pyeloplasty, ureteral anti-reflux surgery, bladder enlargement, valvotomy, etc. are performed for the cause of obstruction, and the specific surgical procedures are open surgery, small incision surgery, laparoscopic surgery and retroperitoneoscopic surgery. Pyeloplasty is chosen for children with obstruction at the ureteral junction of the renal pelvis. What is the choice between laparoscopic and traditional open surgery for pyeloplasty? Depending on the age of the child and the severity of the hydrocele, a pediatric surgeon can choose either small incision surgery or minimally invasive laparoscopic surgery, which has the advantage of being relatively more invasive. What kind of pediatric hydronephrosis is not suitable for laparoscopic treatment? However, with the development of laparoscopic surgical instruments and techniques, laparoscopic surgery can also be safely performed in these children. How to review after hydronephrosis surgery? What are the frequency and items to be checked? In the short term, it is necessary to come to the hospital for follow-up according to the surgeon’s suggestion, and in the long term, it is also necessary to review the ultrasound regularly, the frequency of which depends on the specific condition of the child. Why does the hydronephrosis not disappear completely after surgery? What should I do in this case? Most of the surgery for hydronephrosis is based on the cause of the obstruction, and the dilated renal pelvis will not return to normal after surgery, and the ultrasound often shows some degree of hydronephrosis after surgery, but the hydronephrosis is usually less than before surgery.