I am working as Medical Officer in Purulia Sadar Hospital. My child {current age 2 year and 3 month} is suffering from Posterior urethral valve. He had 2 documented UTI at age of 11 month and 2 year and 1 month. His Serum creatinine:o.6mg, dl at age 1yr 6 month :0.6mg, dl at age 2yr 1 month :o.4mg, dl at age 2yr 2 month before cystoscopy His USG and DTPA Scan{done at age 13 month}report :with in normal limit. His DTPA Scan report:Both kidney are of average size and shape with normal perfusion and no obstruction seen in either kidney.Total GFR:114.14ml, min MCU Report:Posterior urethra is dilated with residual urine in bladder but no reflux. Cystoscopy and valve ablation done at age of 2yr 2 month His urinary stream is improved after cystoscopy.He is under prophylactic antibiotic {Cotrimoxazole}till first attack of UTI i.e.11 month. I have the following questions 1.How the chance of residual valve or stricture can be excluded_? 2.Is Urodyanomic study is required_?-if required any centre for urodyanomic study in Kolkata in this age group. 3.How long the prophylactic antibiotic to be continued_? 4.Prognosis of my child in future{chance of Renal failure }