[Radical prostatectomy: usefulness of selective electromyography of the periurethral sphincter in the assessment of urinary continence].

The exact mechanisms of urinary continence in patients submitted to radical prostatectomy remain unknown. The aim of our study was to evaluate these mechanisms of continence through a complete urodynamic study, with a special emphasis on selective electromyography of the periurethral aphincter. Of a total of 10 consecutive patients who underwent radical prostatectomy between 1990-1993, a complete clinical control of urinary continence was demonstrated in 7 patients. The complete urodynamic work-up and particularly selective electromyography of the periurethral sphincter permitted evaluating the distal sphincteric mechanism and the degree of functional capacity. All of the cases showed loss of motor units, diminished electromyographic sphincter activity and incomplete lesion of the inferior motor neuron. The present study analyzed the pathophysiological, clinical and urodynamic aspects of these patients.