Erection and priapism: a new physiopathological concept.

For normal erection two mechanisms are essential: the first provides increased arterial inflow, most probably this is obtained due to the activity of the intimal cushions within the arteriae helicinae and within the shunt vessels. The second mechanism uses increased arterial blood flow; this could be obtained due to the activity of the trabecular muscle fibers of the corpora cavernosa. In consequence, we would deal with two different types of priapism: one type--high-flow priapism--occurs at the level of the arteriae helicinae and the intimal cushions and provokes a high-flow situation, and the second type, with blood stasis in the corpora cavernosa, occurs at the level of the trabeculae due to persistent contraction of the smooth muscle fibers. The prognosis of the second type is much less favorable and should be cured by surgery within the first 48 h.