How wide a urethra should we produce?

To determine the correct size for an individually tailored neourethra. The urethra to be reconstructed should be a continuation of the native, proximal urethra in both size and structure. Similarly to anorectal malformations, the normal urethra terminates where the normal healthy structure disappears, that is at the division of the corpus spongiosum, and the width at this point should be regarded as a reference feature for reconstruction.

Eighty-two patients aged 10 months to 16 years admitted for primary hypospadias repair were examined. Two measurements were performed: one with the meatus intact and one after incision of the hypoplastic ventral wall to the bifurcation of the corpus spongiosum. Hegar dilators of 1-7.5 mm were used. The size of the external meatus before and after incision was compared with normal values from the literature.

After incision of the external meatus, its width had increased considerably in most patients from a mean value of 2.97+/-1.107 (SD) mm to 4.17+/-0.742 mm. The mean size of the external meatus in healthy boys was 3.69+/-0.43 mm. Upon incision, the external meatus was shifted proximally from distal 50%, middle 39% and proximal 11% to 24.4%, 59.7% and 15.9%, respectively.

The width of the external meatus at the division of the corpus spongiosum should be regarded as the reference size in reconstruction of a neourethra. Incision of the hypoplastic urethral wall results in a proximal shift of the external meatus and consequently in hypospadias classification.