Relevance of sympathetic dyssynergia in the region of external urethral sphincter: possible mechanism of voiding dysfunction in the absence of (somatic) sphincter dyssynergia.

The genesis of the cystourethrographic appearance of external sphincter spasm in 11 paraplegics with complete lower motor neuron bladders was examined. By the demonstration of its close association with a postural increase in the urethral pressure and catecholamine release, and its responsiveness to alpha-adrenolytic drugs an external sphincter spasm was suggested to be a result of sympathetic dyssynergia in the region of the external sphincter. The smooth muscular component in this region is believed to be a responsible unit of this disorder, since its surgical ablation by means of radical transurethral resection of the prostate uniformly resulted in the relief of sympathetic dyssynergia. The clinical implication of this disorder in the management of vesical dysfunction of the lower motor neuron type is discussed.