The aim of our study is to describe MRI appearance of a posterior rectal pouch (PRP) for patients managed for low rectal endometriosis by large full-thickness disc excision and to assess its relationship with postoperative functional digestive symptoms.

Single center retrospective study including patients managed by low/mid rectal disc excision using a semi-circular stapler (the Rouen technique) from June 2009 to October 2016. Intraoperative findings and data provided by standardized gastrointestinal self-questionnaires (GIQLI, KESS, Wexner and Bristol), before and 1 year after the surgery, were prospectively recorded. Postoperative pelvic MRI were reviewed and PRP was assessed in three planes and its volume was estimated on a 3D T2 weighted sequence.

Eighteen patients were included in the study. All patients had postoperative PRP while none of them presented with rectal stenosis. The mean (± SD) volume of the PRP was estimated at 66 ± 32 mL. The mean antero-posterior diameter was 56 mm ± 22 mm, mean height at 44 mm ± 15 mm and mean width at 46 mm ± 11 mm. No positive correlation between the volume of the PRP and the GIQLI questionnaire was found at one year after surgery (r = −0.24, 95%CI -0.51−0.69, p = 0.44).

Large disc excision of low and mid rectum leads to a posterior rectal pouch, with no significant impact on postoperative functional digestive outcomes, but it is not followed by bowel stenosis.