Detrusor Sphincter Dyssynergia

Abstract

Detrusor sphincter dyssynergia is defined as the lack of external sphincter relaxation during voluntary voiding. This should not be confused with the term “detrusor dyssynergia” which has been applied to the unstable bladder. Detrusor sphincter dyssynergia frequently results in an incomplete voiding effort with elevated residual urine volumes. This condition commonly accompanies detrusor hyperreflexia and may occur in some patients without neurologic disease as a habituation to using a “guarding” reflex to prevent urinary leakage with detrusor instability. The first defense against urine loss is the voluntary contraction of the external striated sphincter of the urethra when an unstable bladder contraction occurs. The end result is evidenced by the trabeculation found in the bladder on cystoscopic examination, the increased EMG activity of the pelvic floor during attempted voiding, and the seemingly paradoxial increased residual urine columes resulting from this involuntary obstruction to urine flow.