Functional Urethral Obstruction (FUO)

Abstract

Fistula and stenosis are well-recognized complications after any surgical repair of hypospadias. The standard approach to exclude distal stenosis is to pass an F8 catheter through the new urethra. If the catheter passes without difficulty, the surgeon assumes that there is no distal stenosis. This was true before the introduction of the TIP technique. The author as well as many other surgeons encountered many children presenting with obstructive symptoms and signs or the recurrence of fistula despite the ability to pass catheter F8 through the new urethra. This is called functional urethral obstruction (FUO) because there is a functional obstruction although anatomically, it is possible to pass a F8 catheter. The mechanism of FUO is that sometimes the gap resulting from incision of the urethral plate does not heal by epithelialization resulting in a good sized urethra nor as a linear scar (resulting in meatal stenosis or urethral stricture) but as a deep contracted groove that widens when inserting a rigid bougie or catheter and recoils again after removal of the rigid object. Patients with FUO have the following in common: (1) no obstructive problems before hypospadias repair, (2) they all had TIP repair, (3) the ability to pass F8 catheter without difficulty (excluding anatomical stenosis or stricture), and (4) these obstructive problems disappear completely after reconstruction of a new wide urethra.