Electrourethrogram: study of the electric activity of the urethra and its clinical significance

Apart from the urethral sphincters, the electric activity of the urethra has not been fully addressed in the literature. We investigated the hypothesis that also the non-sphincteric part of the urethra possesses electric activity which may have clinical significance.

Urethral electric activity was studied in 24 healthy volunteers (mean age 40.6 +/- 13.6 years, 14 women). Two electrodes in women and three in men were applied to the urethral mucosa distal to the striated urethral sphincter. A manometric catheter was placed into the penile urethra in men and distal to the striated sphincter in women.

Monophasic negatively deflected slow waves were recorded. Their frequency, amplitude and conduction velocity were identical in the electrodes of the individual subject and were reproducible. The slow waves were followed or superimposed by fast activity spikes or action potentials which occurred randomly and were associated with urethral pressure rise. The pattern of electric activity was stable in the same subject on all test sessions.

A normal electrourethrogram could be identified. It consisted of slow waves and action potentials. The waves had a regular rhythm. The action potentials appear to have a motor activity and are suggested to clear the urethra of the residual urine and secretions that may exist in the urethra after micturition. The clinical significance and diagnostic role of the electrourethrogram need to be further investigated.