Patient: Dear Doctor: Hello! I found that my child had hydronephrosis in both kidneys at 21 weeks, the renal cortex was thinning, at 28 weeks the left hydronephrosis was 2.1cm, the right hydronephrosis was 2.3cm, the left parenchyma was 0.35cm thick and the right was 0.21cm. later the child was born prematurely at 31 weeks, the ultrasound showed that the hydronephrosis in both kidneys was aggravated, the left parenchyma was 0.3cm and the right parenchyma was 0.18cm, the ureter was not dilated, the bladder wall was thickened, the child The doctor initially judged that it was a posterior urethral valve and recommended surgery. What are the risks? If not, is there a risk of kidney failure and life-threatening consequences for the baby? 2, What is the success rate of posterior urethral valve surgery and can it be recovered as usual? Children’s Hospital Pediatric Urology: Hello, posterior urethral valves need to be diagnosed by voiding cystourethrography and cystoscopy can clearly diagnose and treat them, (check out my article on cystoscopy for two more articles). Posterior urethral valves require emergency surgery to relieve urinary tract obstruction, otherwise they can aggravate the impact on bladder function as well as renal function, and can even cause electrolyte disturbances, severe urinary tract infections, and renal failure. However, the posterior urethral valve may cause a series of sequelae, especially it may cause valve syndrome, even if the urinary line seems to be thick and smooth, as the child grows and develops, the bladder function and kidney function will become worse and worse, and gradually kidney insufficiency or even kidney failure will occur. Of course, there are cases in which children with posterior urethral valves recover well after surgery. Posterior urethral valves should be treated as early as possible, and even if cystoscopy is possible, a catheter should be left in place or a cystostomy should be performed.