ANATOMICAL STUDIES OF HYPOSPADIAS

Purpose: Hypospadias is the most common congenital anomaly affecting t he penis. Successful repair depends on an accurate understanding of an atomy. We compared the anatomy of hypospadiac and normal fetal penises . Materials and Methods: A fetal penis at 33 weeks of gestation with d istal shaft hypospadias was serially sectioned and compared to 10 norm al human fetal specimens at 8 to 32 weeks of gestation. Immunohistoche mical localization was performed with S-100 protein and protein gene p roduct 9.5 to localize neurons. Blood vessels were localized by the pr esence of red corpuscles, and immunohistochemical staining with von Wi llebrand's factor and factor VIII. Three-dimensional computer reconstr uctions of the nerves, corporeal bodies, tunica and urethra of the hyp ospadiac and normal fetal penises were compared. Results: Except at th e region of the abnormal urethral spongiosum and glans, the hypospadia c and normal penises showed no difference in neuronal innervation, cor pora cavernosa and tunica albuginea architecture and blood supply. The nerves started proximally as 2 well defined bundles under the pubic r ami superior and slightly lateral to the urethra. As the 2 crural bodi es converged into the corpora cavernosa, the nerves diverged, spreadin g around the cavernous bodies up to the junction with the urethral spo ngiosum without remaining at the 11 and 1 o'clock positions. Along the entire shaft of the penis there were no neuronal structures at the 12 o'clock position. The most striking difference was in vascularity. In the hypospadiac penis factor VIII immunostaining revealed huge endoth elial lined vascular channels filled with red blood cells. In contrast , the normal penis had well defined small capillaries around the ureth ra that fanned out into the glans. Vascularity was also extensive unde r the urethral plate. Nerve distribution in the abnormal glans was als o less extensive than in the normal penis. Conclusions: Increased know ledge of normal and hypospadiac penile anatomy with respect to the ner ves, corporeal bodies, glans and vascularity is useful for the strateg ic design of penile reconstructive procedures.