☆ Do all pediatric hydronephrosis require treatment? Indications for surgery: obvious obstructive symptoms; total or divided renal impairment; complicated urinary stones or infection, hypertension, etc. Perinatally detected hydronephrosis by ultrasound: if not combined with low amniotic fluid volume, ultrasound review and intravenous urography will be done 1-3 weeks after birth. Mild dilatation of the renal pelvis and calyces can be observed by ultrasound follow-up. When the anteroposterior diameter of the renal pelvis is less than 30 mm or the renal nuclear scan shows fractional renal function greater than 40%, the patient can be conservatively observed. When there is progressive pelvic dilatation (anteroposterior diameter of the renal pelvis greater than 30 mm) or renal nuclear scan showing fractional renal function of less than 40%, the child has significant renal impairment and requires prompt intervention. In conclusion, pyeloplasty is indicated in the following cases during the observation period: 1 renal impairment: fractional renal function drops below 35-40%; 2 progressive dilatation of the renal pelvis; 3 no progressive renal impairment but obstruction persists for 4-5 years without relief. ☆ Does the kidney have to be removed for hydrocele surgery? It is rarely necessary to remove the kidney. ☆ Will the surgery affect the kidney function in the future? The purpose of surgery is to protect kidney function from damage, and successful surgery will not affect kidney function. ☆ What are the main surgeries for pediatric hydronephrosis? Dissection pyeloplasty is the best. In recent years, laparoscopic pelvic ureterotomy has been performed in large pediatric urology centers in Beijing, Shanghai, Chongqing, Nanjing, etc. The postoperative results are good, with little trauma and quick recovery. ☆ What is the choice between laparoscopic and traditional open surgery in pyeloplasty? The surgery is decided according to the surgeon’s experience, and both have the same effect by skilled surgeons. ☆ How to review after hydronephrosis surgery? What is the frequency and items to be checked? Personally, we recommend to review ultrasound at least 3, 6, 12 and 24 months after surgery, and renal nuclear scan and intravenous urography if necessary. ☆ Why some children’s hydronephrosis does not disappear completely after surgery? What should I do in this case? Only a small percentage of children with hydrocele completely disappears after surgery. Most children have successful surgery as long as the degree of hydrocele subsides compared to that before surgery.