Changing concepts of hypospadias curvature lead to more onlay island flap procedures.

From 1987 through 1992, 1,109 primary hypospadias operations were performed at our hospital, of which 374 (33%) were onlay island flap procedures. In contrast, from 1982 to 1987 only 66 of 657 primary hypospadias repairs (10%) were onlay island flaps. The increase in this type of repair stems from the observation that in most cases of hypospadias the urethral plate is not the cause of penile curvature. Intraoperative artificial erection after skin take down revealed that only 50 of the 374 patients (13%) still had a significant bend. After experience demonstrated that the residual bend was not due to a fibrous urethral plate, but rather to a generally mild (20 to 30 degree) corporeal disproportion, correction was achieved by dorsal tunica albuginea plications. We conclude that better healing of the onlay flap to spongiosum supported urethral plate may account for the lower fistula rate (6%) observed with the onlay island flap hypospadias repair, and even in severe cases of hypospadias the urethral plate is usually healthy and it does not require division to produce a straight penis.