Neurologic aspects of detrusor-sphincter dyssynergia, with reference to the guarding reflex.

Of 137 patients with neurogenic detrusor hyperreflexia 71 with and 66 without vesicosphincter dyssynergia were analyzed. Intracranial lesions did not lead to vesicosphincter dyssynergia, which occurs only after spinal cord transection. The normal increase in striated sphincter activity with bladder filling (guarding reflex) usually is lost, while vesicosphincter dyssynergia usually appears after complete spinal cord injury. This finding provides evidence of supraspinal mediation of detrusor-sphincter interaction. Vesicosphincter dyssynergia is hypothesized to be an abnormal flexor response of the perineal musculature to bladder contraction, which is peculiar to humans.