Corpus cavernosum electromyography revisited: defining the origin of the signal

We performed this study to identify the source of complexes recorded during corpus cavernosum electromyography.

A total of 10 healthy male volunteers 19 to 54 years old (mean age 36) with normal erectile function, participated in the study. A Porti electrodiagnostic system (TMS International, Enschede, The Netherlands) connected to a notebook computer recorded low frequency corpus cavernosum electromyography complexes via penile surface electrodes in 3 phases. In phase 1 baseline corpus cavernosum electromyography was recorded for 30 minutes. In phase 2 penile skin block was performed followed by 30 minutes of corpus cavernosum electromyography recording. Phase 3 consisted of intracavernous block followed by corpus cavernosum electromyography recording for 30 minutes. During all 3 phases startling auditory stimuli and median nerve stimulation were used at random intervals to evoke a sympathetic nervous system response. A suprapubic electrode was used as a control to record sympathetic electrodermal activity.

In phase 1 all subjects had spontaneous and evoked corpus cavernosum complexes. The penile skin block used in phase 2 did not affect the presence of these complexes, which remained present in all subjects. During phase 3 no spontaneous or evoked corpus cavernosum complexes were recorded in any subjects, indicating that the intracavernous block eliminated the corporally generated signal. All subjects in all 3 phases demonstrated a sympathetic electrodermal response in the suprapubic electrode in response to evoking stimuli.

This study confirms the penile cavernous tissue, and not the penile skin or surrounding tissue, as the origin of the corpus cavernosum electromyography complex. Further refinement of this technique may render it useful in the evaluation of neurogenic and myogenic erectile dysfunction.