EP298 - Midgut Volvulus after IPAA Secondary to Pouch Twists: Is there a Safe Zone for Placement of the Pouch Mesentery?

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Purpose/Background: Midgut volvulus (MGV) following ileal pouch-anal anastomosis (IPAA) is a rare but potentially devastating complication which left untreated may result in loss of small bowel, and mortality has been reported. Patients with MGV after IPAA may undergo repeated emergent operations with adhesiolysis and detorsion of the volvulus, yet still recur. Although MGV after IPAA may be related to adhesions, otherwise asymptomatic pouch twists may, as the pouch naturally elongates over time, result in twisting of the small bowel mesentery proximal to the fixed pouch twist, resulting in recurrent MGV. The definitive management of MGV after IPAA has not been reported. Herein, we report our experience with pouch revision for recurrent MGV after IPAA.

Methods/Interventions: Patients who underwent surgery for recurrent MGV after IPAA between 2022 and 2024 were identified from our Pouch Registry. Patient characteristics, surgical interventions aimed at preventing recurrence, and short-term postoperative outcomes were reviewed. The degree of pouch twist was noted intraoperatively in all cases, with posterior midline representing zero degrees of rotation. Pouch inlet transposition was defined as a limited small bowel resection with re-implantation of the afferent limb into the prior tip of the J such that the torsional forces on the proximal mesentery were effectively short-circuited.

Results/Outcomes: Five patients were referred to our center for recurrent MGV after IPAA. All patients (100%) were females, median age 43.5 years old; all (100%) of index IPAAs were for ulcerative colitis; 3 (60%) were laparoscopic and 2 (40%) were 3-stage procedures. Median time from index IPAA to referral for pouch revision was 9 years (range, 5 – 24 years). All patients had a history of urgent or emergent diagnostic laparoscopy or exploratory laparotomy (range, 1 – 5 operations) for MGV, yet still recurred. One patient (20%) was treated with rectal and gastric decompression tubes prior to hospital transfer. Patients underwent extensive preoperative work-up including pouchoscopy, pouchograms, computed tomographic enterography, anorectal manometry, and nutritional assessment. At the time of elective exploration (4 open, 1 laparoscopic), all patients were noted to have pouch twists of varying degrees (Table 1). Surgical interventions included pouch inlet transposition (40%), pouch excision with neo-IPAA (20%), pouch mobilization with pouch pexy (20%), and small bowel resection with end ileostomy (20%) as bridging procedures before planned pouch inlet transposition. Four patients (80%) had small bowel resections ranging from 5 to 40 cm, and 3 patients (60%) were diverted. The median duration of surgery was 206 (range, 197 – 321) minutes, with a median postoperative hospitalization of 15.2 (10 – 28) days. No ICU admissions or 30-day mortalities occurred. Based on this experience, a safe zone for placement of the pouch mesentery was conceptualized (Figure 1).

Conclusion/Discussion: This is the first report to support pouch twists as an etiology of recurrent MGV after IPAA, and pouch twists should be considered in the differential diagnosis of MGV after IPAA. A variety of definitive surgical approaches, typically with limited small bowel resection, were used to address the underlying pouch twist with the aim of preventing recurrence of the volvulus. Our experience suggests that at the time of index pouch, placement of the pouch and its mesentery in the safe zone ( < 90 degrees rotation off posterior midline in either direction) may prevent this rare yet morbid complications.