Sensory conduction velocity of dorsal nerve of the penis during pharmacoerection: a more physiological technique?

Abstract

Sensory conduction velocity (SCV) of the dorsal nerve of the penis is technically difficult to perform at rest and very slow SCV has been observed in the literature. This study evaluates the effect of pharmacoerection on the SCV measurement. Twenty-four men, 16 with a normal neurologic examination, 8 with a diabetic neuropathy, were studied at rest and after a 20-micrograms injection of prostaglandin E1. Only 5 subjects had a recordable potential at rest. The mean SCV increased from 32.3 +/- 6.7 to 47.4 +/- 8.2 m/s after injection. Nine had only a recordable potential after injection. Ten had no potential at all, but 6 of them had a diabetic neuropathy. Pharmacoerection was helpful in 37.5% of the subjects to obtain a sensory potential. Moreover, pharmacoerection may be the best way of calculating dorsal nerve SCV, as 47.4 m/s is what should be expected for a large myelinated nerve. This may be due to a correct interelectrode distance measurement as full tumescence may straighten the nerve at an individual and physiological length.