Barium trapping in rectoceles: are we trapped by the wrong definition?

Background: Barium trapping within a rectocele is a criterion used by surge ons to select which patients with rectoceles should undergo operative repai r. This proctographic study compared the presence and depth of barium trapp ing within a rectocele on postevacuation radiography with those seen on pos ttoilet radiography after further evacuation in the privacy of the bathroom . Methods: Eighty-two consecutive patients with evidence of barium trapping o n postevacuation radiographs of a fluoroscopic dynamic cystoproctographic e xamination were reviewed retrospectively. The size of the rectoceles and th e depth of barium trapping on the postevacuation and subsequent posttoilet radiographs were measured. Results: The posttoilet radiographs showed resolution of the barium trappin g in 47 (57%) of the 82 patients. Resolution of the trapping was directly r elated to rectocele size. The mean differences in the depth of barium trapp ing between the postevacuation and posttoilet radiographs were significant for all sizes of rectocele. Conclusion: Barium trapping in rectoceles changes with the degree of rectal evacuation. More complete evacuation was shown on the posttoilet radiograp h than on the postevacuation radiograph. Consequently, the posttoilet radio graph may be more appropriate for the preoperative assessment of barium tra pping within rectoceles.