Urethral pressure variations in women with neurourological symptoms: II. Relationship to urethral smooth muscle

Simultaneous urethrocystometry and electromyography from the urethral striated muscle during bladder filling was performed on female patients complaining of neurourological symptoms. Their maximum urethral pressure varied between 20 and 84 cm H2O. To study the effect of the urethral smooth muscle on the urethral pressure variations, a bilateral pudendal block was applied successfully in 12 patients. It was found that in 1 patient the urethral pressure variations were caused by the urethral striated muscle only, in 4 patients they were caused mainly by the urethral striated muscle, in 2 other patients they were caused equally by urethral striated and smooth muscle, and finally in 5 patients mainly by urethral smooth muscle. By eliminating the urethral striated muscle activity by pudendal block the maximum urethral pressure was reduced 20 to 84%.