Transcutaneous registration of cavernous smooth muscle electrical activity: noninvasive diagnosis of neurogenic autonomic impotence.

Registration of cavernous electrical activity was shown to be a possible method for the evaluation of cavernous autonomic innervation. Recent studies in patients with normal erectile function showed that cavernous electrical activity is synchronous throughout the entire cavernous bodies. Therefore, we examined the feasibility of transcutaneous registration of cavernous electrical activity in 8 normal and 62 impotent patients. In the sitting patient cavernous electrical activity was recorded with a 2-channel electrophysiological unit. Recording was done with a coaxial needle electrode in the proximal left cavernous body and with surface electrodes bilaterally on the penile shaft. In 7 of 8 normal patients swelling of the penile shaft after circumcision resulted in a dramatically decreased amplitude of the potentials. In 41 of 62 impotent patients recordings were similar. In 10 of 62 patients no recording or markedly decreased amplitudes were noted with the surface electrodes and in these patients a small penis or penile retraction with consecutive electrode displacement was found. Careful repositioning of the surface electrodes with the patient in the supine position resulted in similar recordings in 9 (inconsistently in 4). In 11 of the 62 patients more information was obtained with the surface than with the needle electrode. Our results show that recording of cavernous electrical activity can be done in a completely noninvasive manner using surface electrodes with similar or even better information obtained than with needle electrodes.