Successful nutritional treatment of superior mesenteric artery syndrome in a non-malnourished patient: a case report

CASE REPORTOur patient is a 14-year-old boy with severe scoliosis treated by spinal casting, scheduled for spinal arthrodesis.Six months before surgery, he was diagnosed with Crohn's disease requiring anti-TNF therapy, leading to postponement of the operation.Adalimumab induced deep remission with complete resolution of symptoms and normalization of fecal calprotectin (<30 g/g) within one year.At age 15, given the sustained remission, anti-TNF therapy was discontinued to perform arthrodesis under optimal safety conditions, as such treatment increases postoperative complications and should be stopped ideally 4 weeks before and after surgery.During the delay, the spinal curvature slightly progressed, necessitating an extended arthrodesis from T6 to L4.No cranial halo was required.His general condition improved, notably weight gain, and surgery was performed at a normal BMI of 19.2 kg/m (Fig. 1).Twenty-four hours postoperatively, the patient developed severe nausea and bilious vomiting.Despite fasting and gradual reintroduction of enteral feeding, each attempt triggered occlusive symptoms (bilious vomiting and abdominal pain).No signs of Crohn's flare or stenosis were found: no hypoalbuminemia, normal inflammatory markers, rapid postoperative CRP decrease, and normal ferritin (fecal calprotectin could not be measured due to absence of stool).Imaging showed no bowel inflammation.Intermittent macroscopic hematuria was also noted.An abdominal ultrasound on day 5 was normal.On day 11, an upper gastrointestinal contrast study revealed transient contrast stagnation in the second duodenal portion with delayed passage into the third.Contrast-enhanced CT demonstrated compression of the third duodenal segment between the superior mesenteric artery and aorta with a "thread-like" appearance and proximal left renal vein dilatation, consistent with nutcracker syndrome and superior mesenteric artery syndrome (SMAS) (Fig. 2).A multidisciplinary discussion (pediatric surgeons, orthopedic surgeons, gastroenterologists) favored conservative management, despite the patient's adequate preoperative nutritional status.Considering the recent complications, resumption of anti-TNF therapy was deferred.Exclusive enteral nutrition (EEN) using Modulen IBD , an isocaloric (1 kcal/mL) semi-elemental polymeric formula, commonly used in Crohn's disease, was initiated.Estimated nutritional requirements were ranged from 2800 and 3100 kcal/day for a 60 kg adolescent with low physical activity, recovering from scoliosis surgery.Enteral feeding was started at 20 mL/h and progressively increased by 10-20 mL/h every 12 h, up