Striated sphincter participation in distal passive urinary continence mechanisms: studies in male subjects deprived of proximal sphincter mechanism.

Striated urethral sphincter function was studied in passive incontinent and continenet male subjects who were deprived of the proximal sphincter mechanism. Functional assessment of striated urethral sphincter include electromyography and electrostimulation. Varying degrees of diminished striated sphincter excitability and reflex activity were observed in passive incontinent male subjects who also had varying degrees of somatomotor neuron lesions. The studies indicate that the participating role of periurethral striated musculature in distal passive continence mechanisms cannot be ignored.

Urethral striated sphincter responses to electro-bulbocavernosus stimulation.

Electric stimuli of known strength, duration and frequency were applied to the glans penis, and the cystosphincterometric and electromyographic responses of the urethral striated sphincter were recorded. Studies performed on male subjects, including normal men, patients with a neurologic deficit and patients who had undergone prostatectomy, indicate the usefulness of this technique in evaluating the striated sphincter excitability via the pudendal reflex arc. The intravenous administration of diazepam produced a notable increase in the striated sphincter threshold, indicating the applicability of this technique to evaluate the effect of various neuropharmacologic agents on the striated sphincter activity. In addition, the transit time through the pudendal reflex arc was measured with this method to assess the somatic neural integrity of the lower urinary tract. Also, studies on patients with post-radical prostatectomy incontinence have suggested that our technique of striated sphincter evaluation could be applied to the prediction of postoperative urinary incontinence.

Detrusor-urethral sphincter dyssynergia.

Inappropriate contraction or failure of relaxation of either the internal (smooth muscle) or external (striated muscle) urethral sphincter or both coincident with detrusor contraction results in a micturitional disorder known as detrusor-urethral sphincter dyssynergia. Based on our clinical experience with more than 200 spinal cord subjects and serial urodynamic observations on some of these individuals from the time of injury, various grades of dyssynergia (1 to 3) were recognized. The duration and completeness of suprasacral cord injury essentially determined the degree of dyssynergia. Internal sphincter dyssynergia was encountered less often in this group. A review in relation to pathophysiology and management of this micturitional dysfunction is presented.

Functional striated sphincter component at the bladder neck: clinical implications.

Anatomical proximal extension of the striated urethral sphincter muscle towards the bladder neck was assessed functionally in normal male subjects and in patients with upper motor neuron lesions. Synchronous cystosphincterometric studies were performed and urethral pressure responses were studied (contraction complexes) at the vesicourethral junction, the supramontane prostatic urethra and the membranous urethra to repeated bulbocavernosus stimuli. All subjects demonstrated positive responses at the membranous urethra. Contraction complexes with amplitudes of less magnitude were elicited at the vesicourethral junction and at the supramontane prostatic urethra in 48 and 71 per cent of the total number of subjects, respectively. The functional significance of the striated muscle component at the bladder neck in patients with detrusor-striated sphincter dyssynergia is described.

Use of Boari flap in lower ureteral injuries.

We review our experience with the Boari flap to correct distal ureteral injuries. Satisfactory results were obtained in 15 of 21 patients. We believe this procedure should be considered as an alternative to transureteroureterostomy, autotransplantation, and ileal interposition for short or long distal ureteral defects.