Open repair of a primary obstructive megaureter in a child, shown on the left side. The ureter is freed through the opened bladder and then outside it, with its blood supply kept on it, as far as the iliac vessels, and its narrow last segment is removed.
The dilated ureter is then tapered: a strip of its lateral wall is excised, away from the longitudinal vessels on the medial side, and the wall is closed round a catheter.
The tapered ureter is reimplanted through a submucosal tunnel across the trigone to a new opening above and lateral to the opposite orifice. The lesson is where the blood supply runs, how much wall the catheter allows to be taken, and how long a tunnel a wide ureter needs.