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Since the introduction of oral therapy, erectile dysfunction (ED) has become a widely publicized disease. These agents have revolutionized the management of ED and helped identify patients at risk for developing ED and other associated medical conditions. Since the erectile bodies of the penis are nothing more than a complex vascular structure, it has become evident that ED dysfunction may represent a local manifestation of widely systemic disease. Evaluation and management of the patient with ED may have a global impact on the overall health. With that in mind, this chapter represents a review of the current status of ED diagnosis, evaluation, and management.
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The penis is composed of three main functional structures; two dorsal erectile bodies and one ventral urethra. The urethra functions to allow for the egress of urine and ejaculate. Whereas erectile bodies are vital biologic functions, they are not required for erectile functioning. Despite the anatomic association and proximity of the erectile bodies, urination, orgasm, emission, and erectile function can occur independently.
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The corporal bodies are the functional units for penile tumescence. These two parallel structures are anchored proximally at the inferior puboischial rami. Initially, they are separate but fuse in the midline as the penis extends from the perineum. This proximal separation allows for the urethra to assume its position in the ventral midline by passing beneath the crus of the proximal corporal bodies. As the penis extends from the body, it is supported by the suspensory ligament of the penis. This ligament offers erectile support and facilitates directed penetration. The erectile bodies terminate distally beneath the glans penis which acts as a cap over the distal end. The glans penis is contiguous with the corpus spongiosum or spongy sinusoids that surround the penile urethra.
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Another important and underestimated anatomic component for erectile function is the tunica albuginea of the cavernous body. This bilaminar casing has functionality based on its elasticity and pliability. In the flaccid state, the tunica albuginea is soft and relaxed. This allows for open venous drainage to the cavernous sinusoids. In contrast, during tumescence the longitudinal and circular fibers of the tunica albuginea occlude of the emissary veins restricting venous outflow. This leads to corporal filling during the erectile response and ultimately penile rigidity. If the tunica albuginea loses its elasticity, the occlusive process fails and venous leak ED ensues.
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The primary arterial supply originates from the terminal branch of the internal iliac artery. This vessel, the internal pudendal artery, passes through Alcock's canal and divides to give rise to the penile artery. The penile artery branches into the bulbar, urethral, and cavernous arteries. The cavernous artery provides the main arterial inflow to the corporal body. However, perforating branches of the dorsal artery ...