(176) Bridging the Gap Between Decreased Cavernous Tissue Compliance and Venous Leakage: The Role of a Cavernous Tissue Layer Without a Blood Pool That Appears Under the Tunica Albuginea During Erection

Introduction It has been shown that the elastin content in the cavernous tissue of patients with cavernous dysfunction is reduced, resulting in a decrease in compliance of the cavernous tissue. Decreased compliance is thought to cause corporal veno-occlusive dysfunction, i.e., venous leakage, leading to erectile dysfunction. The mechanism of corporal veno-occlusive function is thought to be primarily due to compression of the subalbugineal venous plexus by the tunica albuginea, and secondarily due to occlusion of the emissary veins by stretching of the tunica albuginea. However, we believe that there is still a gap that needs to be bridged between decreased cavernous tissue compliance and venous leakage. Objective B-Flow mode ultrasound observations have confirmed the appearance of a cavernous tissue layer without a blood pool under the tunica albuginea during erection. We hypothesized that the appearance of this layer may be related to venous leakage. We investigated the relationship between the thickness of this cavernous tissue layer and venous leakage. Methods Of 107 patients with erectile dysfunction who were unable to achieve complete erection with intracavernous injection of alprostadil alfadex (Prostandin®), 84 underwent dynamic infusion cavernosometry and cavernosography (DICC) testing. The median age was 35 years (IQR: 29.5-54.5). B-Flow ultrasound was performed before and after intracavernous injection of 10-20 μg of alprostadil alfadex (Prostandin®). The equipment used was a LOGIQ E10® ultrasound system. The thickness of the cavernous tissue layer without a blood pool was measured at three points on each side at the base of the corpora cavernosa of the penis, and the mean of these six measurements was used as the result. DICC was performed on an alprostadil re-dosing schedule. A servo-controlled pump was used to infuse saline and measure the perfusion rate required to maintain a cavernosal pressure of 90 mmHg. Normal cavernous function was defined as a flow rate of less than 20 mL/min required to maintain an intra cavernosal pressure of 90 mmHg. Results DICC revealed 42 patients with normal cavernous function and 42 patients with cavernous dysfunction. The mean and range thicknesses of the cavernous tissue layer without a blood pool in patients with normal cavernous function and patients with cavernous dysfunction were 1.90 ± 0.65 mm (0.86–3.53) and 1.61 ± 0.64 mm (0.00–3.25), respectively. The thickness of the cavernous tissue layer without a blood pool was thinner in patients with cavernous dysfunction (p<0.05, two-tailed t-test). Conclusions B-Flow ultrasound studies revealed that the cavernous tissue layer without a blood pool was formed under the tunica albuginea during erection. This layer was thinner in patients diagnosed with cavernous dysfunction by DICC. Decreased cavernous tissue compliance leads to insufficient compression of the peripheral cavernous tissue by the central cavernous sinusoids, which occurs during erection. As a result, the formation of a cavernous tissue layer without a blood pool is insufficient, and the cavernous sinusoids in the peripheral cavernous tissue layer are not completely obstructed. We believe that this may be the mechanism by which decreased cavernous tissue compliance causes erectile dysfunction due to venous leakage. Disclosure No