Neuromuscular dysfunction of the lower urinary tract with special reference to the influence of the sympathetic nervous system.

Filling cystometry, urethral and anal sphincter electromyography, pressure-flow registration, urethral closure pressure profile at rest and after alpha-adrenoceptor blockade with phentolamine, evoked potential of the bulbocavernosus reflex and denervation supersensitivity to carbachol in a-reflexic bladders were performed in 57 consecutive patients with a localized neurological lesion, in order to evaluate the relative importance of the somatic, the parasympathetic and especially the sympathetic nervous system for the function of the lower urinary tract. In spinal lesions with detrusor hyperreflexia, dyscoordination between detrusor and striated urethral sphincter was dominant, while in cauda equina lesions and in lesions of the pelvic nerves the lack of parasympathetic bladder innervation dominated. It was not possible to identify specific spinal segments controlling sympathetic nervous regulation of the lower urinary tract. The only influence of the sympathetic nervous system was a control of urethral pressure, where a statistically significant smaller proportion of the maximal urethral pressure was affected after alpha-adrenergic blockade in patients with peripheral nerve lesions. All a-reflexic bladders exhibited denervation supersensitivity to carbachol, while carbachol did not change urethral pressure significantly indicating minimal influence of the parasympathetic nervous system on urethral pressure.