Retrocaval ureter: a rare anamoly presenting with pain

A 23 year old patient presented with pain in right flank on and off for more than 3 months duration.He was investigated with ultrasound of KUB region which revealed right sided moderate hydronephrosis with prominent upper ureter.He underwent IVP which showed right moderate hydronephrosis with kinked upper ureter.He was taken up for CT scan for further demonstration of the anamoly which showed retrocaval ureter.The DTPA scan revealed left obstructed system.The patient is planned for laparoscopic uretero-ureterostomy.