loss of the vesico-urethral reflex 'guarding reflex' in which increased urethral sphincter tone parallel to bladder distension, decreased patient vigilance during sleep resulting in reduced muscle tone and urethral closing pressure, decreased sensitivity of the membranous urethra after radical cystectomy, involuntary high-amplitude contractions of the reservoir secondary to bowel peristalsis and shifting of free water from the reservoir wall into the hyperosmolar urine are the main factor causing global and nocturnal polyuria in patient with ONB. Final, there is also evidence suggesting an increase in bowel activity during sleep. Maximum urethral closing pressure (MUCP) is the primary component responsible for daytime continence in patients with an ONB. However, Koraitim et al. suggest that nocturnal incontinence depends on three reservoir parameters: maximal contraction amplitude, baseline reservoir pressure at mid capacity, and MUCP.