Penile calibration for nocturnal penile tumescence studies

Artificial penile erections were created in 23 impotent patients by infusion of heparinized saline solution into the corpora cavernosa. Penile circumference as related to rigidity was accurately assessed. The increase in circumference necessary to produce erection adequate for vaginal penetration varied from 7.5 to 35 mm, whereas for maximum rigidity the penile circumference increase varied between 10 mm and 40 mm. These were then compared with the changes during nocturnal penile tumescence studies. Even though 5 patients in the series had erection greater than 15 mm, 40 per cent of them did not achieve rigidity adequate for vaginal penetration. One patient had nocturnal tumescence of only 12 mm; this, however, was an erection adequate for vaginal penetration. The approach discussed in this article may allow the rational use of portable home tumescence monitoring.