Malrotation

Basics

Incomplete rotation and fixation of intestine during embryogenesis during transition from extracolonic position during week 10 of gestation
Risk factor:
- Heterotaxia syndromes
Associated conditions:
- Gastrointestinal anomalies:
  - Duodenal stenosis, atresia, web
  - Meckel diverticulum
  - Intussusception
  - Gastroesophageal reflux
  - Omphalocele or gastroschisis
  - Congenital diaphragmatic hernia
  - Abdominal wall defect
  - Hirschsprung disease
- Metabolic acidosis
- Congenital cardiac anomalies present in 27% of patients with malrotation. Increases morbidity to 61%.

Duodenojejunal junction remains right of midline
Cecum remains in the upper left abdomen with abnormal mesenteric attachments
Volvulus is a complication of malrotation when small bowel rotates around superior mesenteric artery and vein resulting in vascular compromise to midgut
Abnormal anatomy predisposes to obstruction and other conditions
Usually found in combination with other congenital anomalies (70%): Cardiac, esophageal, urinary, anal
Congenital cardiac anomalies are present in 27% of patients with malrotation
Epidemiology:
- 1 in 500 live births
- High mortality in infants: Up to 24%
- Necrotic bowel at surgery increases mortality by 25×
- Incidence:
  - In neonates, male-to-female ratio 2:1
  - 75% diagnosed newborn period
  - 90% diagnosed by age 1 yr of life
  - 10% may present after age 1 and can present during adulthood

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