Role of enterocoele in obstructed defecation syndrome: proposal of a new radiological and surgical classification

Obstructed defecation syndrome (ODS) is clinically defined as a prolonged (more than 6 months) history of difficult rectal evacuation, including excessive straining, feeling of incomplete evacuation or inability to evacuate without digitation. It is usually related to a functional disorder and it occurs most exclusively in females. Many authors 1-4 have reported an incidence of enterocoele from 19% to 35% in patients with ODS. However, the role of enterocoele (defined as prolapse of the small bowel into the rectogenital space) in this syndrome is still controversial. According to Wexner,7 the etiological classification of enterocele is: primary when factors such as multiparity, advanced age, general lack of elasticity, obesity, constipation and increased abdominal pressure are present, and secondary when it occurs after gynecological surgical procedures, especially hysterectomy. Another classification of enterocoele proposed by Nichols 8 is based on its origin: 1) congenital (unusual deep Pouch of Douglas), 2) pulsion-mediated (caused by chronic increase of abdominal pressure), 3) by traction (associated with a loss of support of the pelvic floor), 4) iatrogenic (after surgical procedures that change the normally-horizontal vaginal axis to vertical). In patients with a uterus, the hiatus between the proximal edges of the fascial layers (anteriorly the pubocervical fascia and posteriorly the rectovaginal fascia) is bridged by the cervix and the uterine fundus. One of the most common causes of enterocoele in non-hysterectomized patients is an unusually deep Pouch of Douglas.5 In hysterectomized patients failure to reattach these layers results in a fascial defect so the peritoneum comes into direct contact with the Pouch of Douglas.6 A grading system, proposed by Hale et al., classifies enterocoele as small when the bowel extends 2 to 4 cm below the vaginal apex, moderate when extension reaches 4-6 cm, and large when this distance is greater than 6 cm. Extension up to 2 cm below the vaginal apex is considered to be within the normal range.9 The most common symptoms of enterocoele are a dragging sensation in the pelvis and pain in the lower abdomen. Many patients report outlet obstruction 3 and assisted defecation. Some develop faecal incontinence. Detection of enterocoele is difficult: up to 84% are missed at clinical examination.11 Its presence and extent can be diagnosed by endo-ultrasonography and by dynamic magnetic resonance imaging,12-14 otherwise the functional relevance of an enterocele is diagnosed only in the late evacuation phase during cinedefecography.15, 16 Defecography or evacuation proctography is a dynamic radiologic technique that involves imaging of the elimination of a barium paste enema from the rectum in order to assess changing anatomic relationships of the pelvic floor and associated organs during evacuation. The main indication to perform cinedefecography is constipation and rectal outlet obstruction.7, 8 The aim of our study is to demonstrate in patients with clinical symptoms of ODS the incidence of enterocoele, the variable relationship between herniated small bowel, peritoneum and rectal ampulla (the enterocoele may sink into the bottom of the cul-de-sac or float within the Pouch of Douglas) and finally to assess the correlation between different groups of enterocoele and ODS.