Only the nose knows: penile hemodynamic study of the perineum-saddle interface in men with erectile dysfunction...

To investigate the differential impact of straddles (A(ns) and B(ns)) and noseless two-cheek seats (A(ntcs) and B(ntcs)) on penile hemodynamics and perineal compressive forces in subjects who cycle in a stationary bicycle.

Subjects underwent cavernosal artery peak systolic velocity (CAPSV) measurements after intracavernosal injection of vasoactive agents while supine, sitting upright on an examination table, straddling a saddle, sitting on a seat, and again supine. Mean perineal compression pressures recorded while straddling the saddles were compared with those while sitting upright.

No differences were found in right and left CAPSV values while supine, sitting upright on an examination table, sitting on a seat, and supine again. Right/left CAPSV (cm/second) values straddling A(ns) and saddle B(ns) (0.7 +/- 2.9/1.5 +/- 6.2 and 0/0, respectively) were significantly lower than values obtained while sitting on A(ntcs) and B(ntcs) (25.6 +/- 13.4/23.8 +/- 12.0 and 17.3 +/- 6.4/18.3 +/- 6.5, respectively) (P < 0.001). Mean perineal compression pressures (mm Hg) on A(ns) and saddle B(ns) (315.2 +/- 39 and 387.9 +/- 64.3, respectively) were significantly higher than values obtained while sitting upright on an examination table (47.6 +/- 5.2 and 46.0 +/- 8.1, respectively) (P < 0.001).

We have identified an objective test to assess if an individual bicycle rider, sitting on a certain shape of bicycle saddle or seat generates sufficient compressive forces at the perineal-saddle interface to obstruct cavernosal arterial inflow. This study also demonstrated that straddling bicycle saddles with nose extensions is associated with perineum-saddle interface compressive pressures that exceed systolic perfusion pressures, significantly diminishing penile hemodynamics.