Urethral function in neurological disorders of the lower urinary tract

Simultaneous measurements of intravesical pressure, urethral pressure, and electromyographic activity of perianal muscles were performed during bladder filling and voiding in 56 patients with neurogenic lower urinary tract dysfunction. In 21 patients simultaneous measurements were taken of the EMG activity of the striated-muscle external urethral sphincter. During bladder filling the urethral pressure was found to correspond to the EMG activity of both muscles only in those patients with normal urethral pressure. During voiding the EMG activity of neither muscle corresponded well with changes in urethral pressure. The EMG activity of perianal muscles corresponded to the activity of the external urethral sphincter during filling of the bladder but not during voiding.