misrotation

Misrotation refers to abnormal rotation or fixation of organs that normally rotate during embryonic development. The term is most often used in reference to midgut malrotation, a condition in which the intestines fail to complete their normal rotational sequence around the axis of the superior mesenteric artery. In this context, misrotation can result in malpositioning of the bowel and a narrow mesenteric base that predisposes to twisting (volvulus) and obstruction.

During normal development, the midgut undergoes about 270 degrees of counterclockwise rotation and then fixes to the posterior abdominal wall. Disruption of this process leads to varying patterns of misrotation, including nonrotation, reverse rotation, and mixed malrotation. Etiology is often not clear but may be congenital and associated with other anomalies or genetic syndromes.

Clinical presentation varies by age. Neonates may present with bilious vomiting, feeding intolerance, and abdominal distension due to obstruction or volvulus. Older children and adults may have intermittent abdominal pain, vomiting, or chronic symptoms, and some cases are discovered incidentally on imaging performed for unrelated reasons.

Diagnosis is typically suggested by imaging. An upper gastrointestinal series is the gold standard for evaluating intestinal rotation and can demonstrate abnormal duodenal position or a corkscrew appearance with volvulus. Ultrasound, CT, or MRI can show abnormal cecal position, mesenteric root narrowing, or SMA/SMV orientation and are useful in adults or equivocal cases.

Management depends on symptoms and volvulus risk. Symptomatic malrotation with volvulus or obstruction requires urgent surgical intervention, usually a Ladd procedure, which detorses the bowel, broadens the mesentery, divides Ladd bands, and places the bowel in a nonrotated configuration with appendectomy. Asymptomatic malrotation may be observed in some cases, but many clinicians advocate surgical correction due to volvulus risk. Prognosis after treatment is favorable with prompt management.