Surgical anatomy of the penis in hypospadias: magnetic resonance imaging study of the tissue planes, vessels, and collaterals.

OBJECTIVE To report the surgical anatomy of the penis in hypospadias with study of vessels in relation to fascial planes, glans, corpora cavernosa, and corpus spongiosum using magnetic resonance imaging. MATERIALS AND METHODS Twelve hypospadias presenting at older age (8-20 years) were studied with 1.5-T magnetic resonance imaging scanner and a 3-inch surface coil. Precontrast and postcontrast images were acquired using fast-spin echo sequences in sagittal, coronal, and transverse planes. The findings were processed in Volume Share 4.5, version Workstation, of General Electric Healthcare. Anatomic findings were verified during surgery. With imaging and surgical findings, a 3-dimensional conceptual diagram of surgical anatomy was created. RESULTS Distinct layers of the skin, dartos fascia, Buck fascia, tunica albuginea, glans urothelium, lamina propria of glans, and corpus spongiosum were delineated with their spatial relationship. Axial pattern vessels of the dartos and its anastomosis with branches of dorsal penile vessels at the coronal sulcus, perforators along the corpus spongiosum, subglanular extension of the fascia, and intraglanular branches of the dorsal penile artery forming an arcade were visualized. CONCLUSION Dorsomedial and dorsolateral axial pattern vessels are present in penile dartos with relative avascularity at dorsal midline in most cases. Subglanular extension of Buck fascia fused with the basal lamina propria of glans forms a barrier between the tip of corpora and the intraglanular arcade of vessels. Collaterals are present at coronal sulcus, along the bifurcated corpus spongiosum, and the dartos enabling blood flow between the terminal most branches of the external and internal pudendal vessels.