Retrograde intussusception post Roux‐en‐Y gastric bypass
The decision was made for emergency surgery. Initial laparoscopy confirmed small bowel intussusception with possible small bowel ischaemia. The intussusception was difficult to reduce laparoscopically, and hence a small midline laparotomy was performed. Findings included a long segment of retrograde small bowel intussusception with entry point slightly distal to the previous Roux‐en‐Y jejuno‐jejunostomy. The distal common tract had intussuscepted proximally up into the alimentary limb causing gross dilatation and obstruction. On manual reduction of the intussusception, an area of ischaemia with focal perforation was noted (Fig. 1). Approximately 20 cm of small bowel was resected and distal side‐to‐side functional end‐to‐end stapled jejuno‐jejunostomy was performed. The patient progressed well post‐operatively, being discharged on post‐operative day 5. Histopathology was consistent with the clinical picture showing ischaemic necrosis of the small bowel with a focal area of perforation.
Intussusception occurs usually around a lead point with a segment of bowel telescoping distally. Adult intussusception is uncommon accounting for 5% of total cases and causing only 1–5% of intestinal obstructions in adults.1 Tumours, both malignant (27.3%) and benign (25%) account for the majority of adult intussusceptions. Other risk factors include non‐tumourous polyps, inflammatory bowel disease and anatomical abnormalities including Meckel's diverticulum and a mobile caecum. In adult populations, the classical paediatric triad of abdominal pain, bloody stools and a palpable abdominal mass is uncommon, present in only 9.8% of patients often making a clinical diagnosis challenging.2
CT is the preferred imaging modality when investigating suspected adult intussusception with the ‘target sign’ pathognomonic. This is particularly evident if oral contrast has been given, highlighting the intussuscepted area (Fig. 2). Further information including metastases and lymphadenopathy can often be observed on CT and point to underlying pathology.3
Intussusception represents 10.8% of small bowel obstruction post REYGB. In this subgroup of patients, an alternate aetiology needs to be considered. Several hypotheses have been postulated including the staple or suture line of the jejuno‐jejunostomy acting as the lead point or local inflammatory mediators resulting in nodal hyperplasia. The most promising theory is the development of ectopic pacemakers in the alimentary jejunal limb formed because of their transection from the duodenal pacemakers during the original REYGB. These pacemakers generate potentials both distally and proximally leading to retrograde peristalsis.4 This hypothesis may explain the high incidence of retrograde intussusception described post REYGB (69.8%) when compared with patients with virgin bowel (2.3%) (Fig. 3).2
Once diagnosis is established, operative management is the treatment of choice. Although intussusception may resolve spontaneously, surgical intervention is often required, as clinical and radiological evidence is insufficient to rule out ischaemia. Furthermore, in this subgroup of patients, clinical examination of early intra‐abdominal sepsis may be difficult secondary to their body habitus.
Because of the rarity of this presentation post REYGB, there is no consensus on definitive surgical management with successful reports on either resection or reduction with or without plication/pexy of the intussusception.