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

Barium trapping within a rectocele is a criterion used by surgeons to select which patients with rectoceles should undergo operative repair. This proctographic study compared the presence and depth of barium trapping within a rectocele on postevacuation radiography with those seen on posttoilet radiography after further evacuation in the privacy of the bathroom.

Eighty-two consecutive patients with evidence of barium trapping on postevacuation radiographs of a fluoroscopic dynamic cystoproctographic examination were reviewed retrospectively. The size of the rectoceles and the depth of barium trapping on the postevacuation and subsequent posttoilet radiographs were measured.

The posttoilet radiographs showed resolution of the barium trapping in 47 (57%) of the 82 patients. Resolution of the trapping was directly related to rectocele size. The mean differences in the depth of barium trapping between the postevacuation and posttoilet radiographs were significant for all sizes of rectocele.

Barium trapping in rectoceles changes with the degree of rectal evacuation. More complete evacuation was shown on the posttoilet radiograph than on the postevacuation radiograph. Consequently, the posttoilet radiograph may be more appropriate for the preoperative assessment of barium trapping within rectoceles.