Improved hemodynamic response after long-term intracavernous injection for impotence

To investigate the phenomenon of spontaneous erections in patients on long-term intracavernous injection therapy.

We undertook an objective assessment of the penile circulation of 35 patients; 21 used prostaglandin E1 (PGE1) alone and 14 used a combination of papaverine, phentolamine, and PGE1. All underwent duplex ultrasonography before initiation of home self-injection and again after a mean of thirty-one months of treatment (most patients performed injections once or twice a week).

The diameter of the cavernosal arteries did not change significantly after treatment. However, the mean peak flow velocity increased highly significantly (P < 0.001): 17.9 cm/second in the right cavernous artery and 21.2 cm/second on the left before treatment; 24 cm/second on the right and 29 cm/second on the left after treatment. More than one third (13 of 35 patients [35%]) achieved functional erection without injection at least some of the time, giving clinical support to the sonographic findings.

We suggest that the combination of vasodilatory drugs and sexual stimulation may act to improve sinusoidal and penile arteriolar smooth muscle function.