 The investigators propose a prospective blinded randomized control trial RCT to assess the efficacy and safety of a simple method of continuous infusion of a local anesthetic, ropivacaine, via a surgical wound to control pain after ureteropelvic junction UPJ stenosis correction in children during the first 48 hrs after surgery. The investigators hypothesize that this technique will provide greater pain relief post-operatively and reduce the need for systemic opioid use along with a reduction in associated side effects of such analgesics. 