Balloon topography. A simple method of evaluating anal function.

Balloon topography was developed to simultaneously measure anal canal pressure, anal canal length, and anorectal angle. It is performed using a cylindrical flexible balloon placed into the anal canal and rectum and filled with liquid radiopaque contrast dye under low pressure. The pressure of the dye inside the balloon is controlled by the investigator, and does not vary with changes in balloon volume. The shape of the balloon within the anal canal is recorded using fluoroscopy and plain radiopaques. The patient receives less radiation than he would receive during a single contrast barium enema. We have performed the test on 27 subjects including a normal control, rectal prolapse patients, and incontinent patients. Early results demonstrate the usefulness of the test in examining anal sphincter and pelvic floor function in maintaining fecal continence in health and disease. The test measures multiple aspects of anopelvic function simultaneously that previously required separate investigations.