Pouch Septum after Ileoanal Pouch: A Systematic Review of Literature

Background:
Rarely, when ileoanal pouches (IPAA) are constructed using a mid-pouch enterotomy to fire the pouch body staple lines, a full-thickness septum of undivided tissue at the pouch apex may form. Patients with pouch septa may develop symptoms of outlet obstruction and may benefit from endoscopic or surgical septotomy. The incidence, outcomes, and pathophysiology of obstructing pouch septa are not well characterized.
Methods:
We conducted a systematic review using the keywords “apical pouch bridge,” “residual mucosal bridge,” “rabbit ear pouch,” “apical bridge,” “pouch septum,” “pouch fold,” and “pouch bar” across the Medline, Embase, Web of Science, and Cochrane Central databases. All databases were searched from their inception through April 9, 2024.
Results:
A total of 9 studies were identified, comprising 26 patients with symptomatic pouch septa. These included 2 retrospective cohort studies, 1 prospective cohort study, and several case reports and case series. The reported incidence of pouch septa ranged from 1.8% to 10% in 4 studies. The time from pouch surgery to septectomy varied from 6 months to 20 years, with 2 patients diagnosed prior to ileostomy closure. Dyschezia was the most common presenting symptom (n = 20), followed by tenesmus and a sensation of fullness (n = 13). Twenty-two patients underwent surgical septectomy using an EndoGIA stapler and endoanal ligation of the mucosal bridge, while 3 underwent endoscopic septectomy using an needle knife with Endoclip placement. No complications were reported. Symptom resolution was documented in 6 studies involving 23 (88.5%) patients. Only 1 study (Kusunoki 1996) compared 7 patients with symptomatic pouch septa to 28 with normal ileoanal anastomosis. Defecography showed a significantly higher resting anorectal angle in the pouch septa group (98.0 [73-130] vs 85.0 [66-118], p < 0.05), with a smaller resting-to-squeeze shift (p < 0.05), and higher resting-to-strain shift and residual J-pouch volume. Manometry showed no significant differences in maximal resting pressure, squeeze pressure, threshold volume, or maximum tolerable volume.
Conclusions:
This systematic review highlights the rarity and variability of pouch septums. Surgical and endoscopic septotomy appear to be safe and effective interventions, with documented symptom resolution in most patients.