Malrotation of the Intestine

Intestinal malrotation results from abnormal embryological rotation and fixation of the midgut.

The clinically dangerous consequence is formation of an abnormally narrow mesenteric base, allowing the entire midgut to twist around the superior mesenteric vascular pedicle.

Abnormal peritoneal bands, termed Ladd bands, can extend from an abnormally positioned caecum across the duodenum and produce extrinsic duodenal obstruction.

The bowel is typically positioned abnormally:

• Small bowel predominantly right sided
• Colon predominantly left sided

The exact positional abnormality is less important than the narrow mesenteric pedicle and risk of midgut volvulus.

In a neonate or infant, the most important presentation is:

Bilious vomiting.

Bilious vomiting in a newborn must be treated as intestinal obstruction until proven otherwise.

Malrotation without volvulus can produce:

• Intermittent bilious vomiting
• Feeding intolerance
• Episodic abdominal pain
• Poor growth
• Chronic obstructive symptoms

Older children can present with nonspecific recurrent abdominal pain.

Sudden severe pain, abdominal tenderness, haematochezia or shock suggests volvulus with intestinal ischaemia.

A plain abdominal radiograph can be normal and does not exclude malrotation or volvulus.

Upper gastrointestinal contrast study: standard anatomical investigation in a stable infant; determine whether the duodenojejunal junction is abnormally positioned and whether there is evidence of twisting.

Ultrasound can demonstrate abnormal superior mesenteric artery and vein relationships or a whirlpool of mesenteric vessels, but a normal vascular orientation does not reliably exclude malrotation.

When the infant has bilious vomiting plus peritonitis or physiological deterioration, diagnostic imaging should not delay urgent surgical exploration.

Symptomatic malrotation

Definitive treatment is the Ladd procedure.

The operation consists of:

• Inspect for volvulus
• Detorse volvulus counterclockwise if present
• Divide obstructing Ladd bands
• Mobilise duodenum sufficiently
• Broaden the mesenteric base from the duodenum to the caecal region
• Position small bowel broadly on the right
• Position colon broadly on the left
• Perform appendicectomy in most conventional procedures

The objective is not restoration of normal embryological rotation. The objective is creation of a broad mesenteric base that cannot easily twist.

Appendicectomy avoids future diagnostic confusion because the caecum remains abnormally positioned after the operation.

Laparoscopic versus open

Laparoscopic Ladd procedure is suitable for selected stable patients without major bowel distension or ischaemia.

Open laparotomy remains preferable with:

• Haemodynamic instability
• Established midgut volvulus
• Severe bowel distension
• Suspected necrosis
• Need for rapid full bowel assessment

Recent comparative data support laparoscopic treatment in appropriately selected children, although recurrent volvulus remains a concern if the mesenteric base is not broadened adequately.

Incidental malrotation

Management of completely asymptomatic malrotation discovered later in childhood is less straightforward.

In infants and young children, many surgeons favour Ladd correction because catastrophic volvulus cannot be predicted reliably.

In older asymptomatic patients, operative risk and lifetime volvulus risk should be individualised.

Postoperative complications

Important complications are:

• Adhesive small bowel obstruction
• Recurrent volvulus
• Persistent dysmotility
• Short bowel syndrome if previous volvulus damaged bowel

Recurrent bilious vomiting after a previous Ladd procedure must still be evaluated urgently because recurrent volvulus is uncommon but possible.