Malrotation - Clinical Tree

KEY FACTS

Terminology

Malrotation: Any abnormal rotation of small or large bowel, which rotate separately during development
Malfixation: Abnormal position or length of bowel fixation by mesentery, typically associated with malrotation
- Short mesenteric fixation predisposes to midgut volvulus [twisting of midgut about superior mesenteric artery (SMA) → vascular occlusion & potential bowel ischemia]

Imaging

Fluoroscopic GI findings
- 3rd duodenum (D3) never crosses midline, often extends anteriorly on lateral view of upper GI
- Duodenojejunal junction lies right of left pedicle & below duodenal bulb on true frontal view of upper GI
- Variable degrees of colonic malrotation with abnormal cecal position on enema or small bowel follow-through
US/CT/MR
- Duodenal nonrotation: D3 segment fails to pass between SMA & aorta when crossing to left of midline
- Reversal of normal SMA/superior mesenteric vein position (not reliable)
Best imaging tool
- Fluoroscopic upper GI vs. ultrasound debated

Pathology

Typically isolated but common in congenital diaphragmatic hernia, gastroschisis, omphalocele, & heterotaxy

Clinical Issues

Majority present in infancy with nonbilious or bilious emesis, recurrent abdominal pain, or poor weight gain; may be asymptomatic
Treated with Ladd procedure: Untwist volvulus if present, divide Ladd bands if present, reposition small & large intestine into right & left abdomen, respectively

Anterior graphic shows abnormal positions of the small & large bowel. The duodenojejunal junction (DJJ) lies low & midline

, very close to the malpositioned cecum

. This results in a short mesenteric fixation that predisposes to midgut volvulus.

Lateral upper GI image in a 3-year-old child with a history of nonbilious vomiting shows an anterior, intraperitoneal course of the D3 segment with a low position of the DJJ

below the duodenal bulb

, indicating abnormal rotation.

Supine front view of the same patient shows a low DJJ

(below the duodenal bulb

) that fails to cross the midline, consistent with malrotation. Note that there is no twisting or dilation of the duodenum to suggest midgut volvulus or obstructing Ladd bands.