# Internal Hernia With Enteroenteric Fistula After Roux-en-Y Gastric Bypass in an Adult Female

## TL;DR

A rare case of internal hernia caused by an enteroenteric fistula after gastric bypass surgery is reported, highlighting the challenges in diagnosis and the benefits of robotic surgery.

## Contribution

Reports a rare enteroenteric fistula causing internal hernia after Roux-en-Y gastric bypass in an adult.

## Key findings

- Enteroenteric fistula after RYGB is extremely rare and can mimic internal hernias on imaging.
- Robotic laparoscopy enabled successful excision and diagnosis of the fistula with rapid recovery.
- Early surgical exploration is crucial for persistent obstruction despite non-diagnostic imaging.

## Abstract

Internal hernia is a recognized late complication of Roux-en-Y gastric bypass (RYGB), often occurring through mesenteric defects at the jejunojejunostomy (JJ) or Petersen’s space. While most hernias result from anatomical defects, the development of an enteroenteric fistula between small-bowel limbs is exceedingly rare. Such fistulae can mimic adhesive bands or internal hernias, creating diagnostic challenges and potential delays in management.

A 39-year-old woman with morbid obesity, RYGB eight years prior, and gastric pouch revision three years prior presented with severe abdominal pain, nausea, and vomiting. CT imaging showed small-bowel obstruction (SBO) with a transition point near the JJ. Repeat CT with oral contrast confirmed persistent obstruction. Emergent robotic laparoscopy identified an internal hernia caused by a short fistulous tract connecting the biliopancreatic limb to the common channel. The fistula was stapled, excised, and sent for histopathologic confirmation, which demonstrated an enteroenteric fistula with focal acute inflammation. The patient recovered uneventfully, resumed bowel function by postoperative day three, and was discharged on postoperative day four, tolerating a regular diet.

Enteroenteric fistula formation after RYGB is extremely rare, with few documented cases in the literature. These abnormal tracts can alter bowel mechanics and mimic internal hernias on imaging, making preoperative diagnosis difficult. CT findings may suggest obstruction, but rarely demonstrate the actual communication. Early operative exploration remains crucial when obstruction persists despite non-diagnostic imaging. Robotic-assisted laparoscopy offers superior visualization and precise dissection, enabling safe fistula excision and rapid recovery.

Internal hernia secondary to an enteroenteric fistula represents a rare and underrecognized cause of SBO after RYGB. Maintaining a high index of suspicion and employing minimally invasive techniques are key to ensuring timely diagnosis and excellent postoperative outcomes.