Functional disorders: rectoanal intussusception

Abstract

Rectoanal intussusception (RI) is a telescoping of the rectal wall during defecation. RI is an easily recognizable physiologic phenomenon on defecography. The management, however, is much more controversial. Two predominant hypotheses exist regarding the etiology of RI: RI as a primary disorder, and RI as a secondary phenomenon. The diagnosis may be suspected based on clinical symptoms of obstructive defecation. Diagnostic modalities include defecography as the gold standard. Dynamic pelvic magnetic resonance imaging (DPMRI) and transperineal ultrasound are attractive alternatives to defecography; however, their sensitivity is poor in comparison to the gold standard at this time. Management strategies including conservative measures such as biofeedback and surgical procedures including mucosal proctectomy (Delorme), rectopexy, and stapled transanal rectal resection (STARR) procedures have varied degrees of efficacy.

Keywords: Delorme; Rectoanal intussusception; biofeedback; defecography; rectopexy; stapled transanal rectal resection (STARR).

Figure 1

Defecography. The rectum is filled with high density, barium paste. In the seated position, static images are taken (A) at rest, (B) during straining, and (C, D) evacuation. The enfolding of the rectal wall is visualized in the evacuation images.

Figure 2

(A, B) Stapled transanal rectal resection (STARR) procedure. After introduction and fixation of the anal dilator, the posterior rectal wall is protected by a retractor (1) and three one-half purse string sutures are placed 1–2 cm above the hemorrhoidal apex to include the top of the rectoanal intussusception (2). The circular stapler is opened and the head placed above the three anterior one-half purse string sutures. Before firing the stapler, care is taken to ensure exclusion of the posterior vaginal wall (3). The stapler is then fired and withdrawn (4). The steps are then repeated for the posterior resection (5–8) ultimately creating a full thickness circumferential excision of the distal rectal wall.