CONTINUOUS MONITORING OF PENILE RIGIDITY AND TUMESCENCE IN JAPANESE WITHOUT ERECTILE DYSFUNCTION

Continuous monitoring of penile rigidity and tumescence has been proved to be of use for accurate diagnosis of erectile impotence, since it provides objective recording of penile rigidity as well as circumferential expansion. Prior to clinical use of this procedure in Japan, a study was performed to clarify normal features of nocturnal penile tumescence of Japanese and to ensure safety of this procedure. The subjects consisted of 16 normal volunteers, aged from 24 to 44 years. With fully informed consent of the volunteers, nocturnal penile rigidity and circumferential expansion were simultaneously measured for three consecutive nights by means of RigiScan at the base of the penis (base) and at about five milimeters proximal to the coronary sulcus (tip). The minimum circumference of the penis was 62.7±4.6mm (mean±SD) at the tip and 65.4±9.3mm at the base. The maximum circumference, which meant full erection in the normal volunteers, was 102.5±14.2mm at the tip and 108.6±14.7mm at the base. The mean duration of tumescence, i. e. circumference expansion more than 10mm, was 23.0±6.9 minutes at the tip and 38.3±12.0 minutes at the base. The mean rate of episodes of circumference expansion more than 10mm was 0.75±0.27 per hour at the tip and 0.70±0.26 per hour at the base. The maximum rigidity lasting more than 10 minutes was 82.9±10.1% at the tip and 85.4±8.4% at the base. Out of the 16 volunteers, 10 felt discomfort at the last episode of full erection on the penis where the loops were placed. Since the discomfort followed after several episodes of full erection, it did not disturb the assessment of penile rigidity and tumescence. None of the subjects made an error in operating the instrument. With its ambulatory character and safety, the RigiScan will be of use for diagnosis and treatment of patients with erectile impotence.