Enterocele revealed by simultaneous evacuation proctography and peritoneography: does "defecation block" exist?

Pelvic floor weakness may allow prolapse of the bowel into the rectogenital space, forming an enterocele. Enteroceles are believed to obstruct defecation by rectal compression and are therefore considered an abnormal finding on evacuation proctography. With a technique combine evacuation proctography and peritoneography, we prospectively studied constipated patients to reveal the pelvic peritoneal recesses during evacuation and to determine if enterocele actually impairs rectal emptying.

Fifty constipated patients were studied prospectively, Using 20 ml of water-soluble contrast medium, we performed peritoneography, then evacuation protography with 120 ml of intrarectal paste. Lateral evacuation and posteroanterior stress views were analyzed by computerized video capture. Anatomic features and functional measurements of rectal emptying were noted. Posteroanterior views were compared with views in 31 subjects undergoing peritoneography for investigation of groin pain.

Technical failure in three patients left 47 for analysis. A deep rectogenital pouch was seen in 36 patients (77%). Of these, 12 (58%) contained viscera that formed an enterocele, but the remaining 15 patients (42%) showed no visceral filling. Most pouches were apparent only during straining (31 cases, 86%). Peritoneal descent was greater than in controls (p < .0001), of whom only three had small rectogenital pouches. Patients with enterocele were compared with those who had a rectogenital pouch but no visceral filling and those who had no pouch. Standard anatomic measurements by evacuation proctography were not significantly different, but patients with enterocele evacuated more rapidly (p = .008) and completely (p = .021) than did the other two groups.

Combined evacuation proctography and peritoneography is a new technique to diagnose pelvic hernias that occur during evacuation. This technique has shown that a deep rectogenital pouch is common in constipated patients and that just over half such pouches fill with viscera. However, because an enterocele does not impair rectal evacuation, this proctographic finding should be interpreted with caution.