The disappearing bladder--modifying imaging techniques after rectal excision.

Urological complications after abdomino-perineal excision of the rectum are well recognized. One complication is chronic urinary retention, which occurs in 14–50% of patients (Watson & Williams, 1952; Buckwalter et al, 1955; Eickenberg et al, 1976; Neal et al, 1982; Watters et al, 1983). The three main theories explaining causes of bladder dysfunction are direct nerve injury, loss of bladder support and pericystitis (Buckwalter et al, 1955; Eickenberg et al, 1976). Vesical neuropathy is now generally accepted as the main cause of urinary retention and this has been reflected in the emphasis on urodynamic studies, conducted mostly by urologists (Rankin, 1969; Fowler, 1973; Fowler et al, 1978; Neal et al, 1982; Chang & Fan, 1983; Lupton, 1986). We present two male patients who developed posterior–inferior bladder prolapse subsequent to rectal excision and illustrate the modifications of standard imaging technique required to demonstrate the altered anatomy.