malrotation of the gut

Abeer Kanaan

ObjectivesTo discuss and understand :• Normal rotation of gut• Definition of Malrotation• Presentation• Investigation• Treatment• Complication

Intestinal malrotation is described as abnormal positioningor arrest of normal rotation of the bowel loops within theperitoneal cavity in the intrauterine life .

It is caused by defective rotation of primitive intestinal looparound the axis of SMA during embryogenesis that results inabnormal short mesenteric root which predisposes smallbowel to twist around it and lead to midgut volvulus

Stages of Normal Rotation● Herniation● Rotation● Retraction● Fixation

• Development of the primary intestinal loop ischaracterized by rapid elongation, particularlyof the cephalic limb.• The abdominal cavity temporarily becomestoo small to contain all the intestinal loops,and they enter the extraembryonic cavity inthe umbilical cord during the sixth week ofdevelopment

Physiological Herniation

• The primary intestinal loop rotates around anaxis formed by the superior mesenteric artery

• When viewed from the front, this rotation iscounterclockwise, and it amounts toapproximately 270° when it is complete

• Rotation occurs during herniation (about 90°)as well as during return of the intestinal loopinto the abdomen (Remaining 180°)

Rotation

• During the 1Oth week, herniated intestinal loopsbegin to return to the abdominal cavity.

• The proximal portion of the jejunum, the first part to reenter the abdominal cavity, comes to be on the left side

• The caecal bud is the last part of the gut toreenter the abdominal cavity.

Retraction

Intestinal rotation starts at 5th week andcompletes by 11th week.

• Midgut is supplied by SMA.

• Rotation takes place around SMA axis.

• 270 degree counterclock wise rotation ofprearterial and post arterial limb.

• Ladds bands attach to the cecum irrespectiveof its postion at the end of rotation from rightparacolic region.

What is Ladd’s bands?

fibrous stalks of peritoneal tissue that attach the cecum to theretroperitoneum in the right lower quadrant (RLQ).

In malrotation instead of its normal anatomical position in the RLQ it pass over the second part of the duodenum, causing extrinsic compression and obstruction result in obstructivesymptoms.

Normal rotation and fixation result in a wide-basedmesentery that extends from the ligament of Treitz in the left upper quadrant to the ileocecal valve in the right lower quadrant

in malrotation, The portion from duodenojejunal Junction to the cecum Isabnormally short And prone to twist. (There is a risk of volvulus)

>>> The bowel’s abnormal position and connections lead toexcessive mobility, which predisposes to bowel compression,kinking, or volvulus

PresentationUsually in early age, but may present later inlife.75% present during 1st month of life.15% present within the 1st year.• Bilious vomiting remains the cardinal sign ofneonatal intestinal obstruction, andmalrotation must be the presumed diagnosisuntil proven otherwise.

• Other signs in the neonate include abdominalpain and distention.• The inconsolable infant may rapidly deteriorate as metabolic acidosis quickly advances to hypovolemic shock.

• Late signs include abdominal wall erythemaand hematemesis or melena from progressivemucosal ischemia.

acute midgut volvulus

• Sudden onset of bilious vomiting in apreviously healthy, growing infant.

• With the onset of proximal intestinal obstruction, the distal colon empties; lower abdomen may appear scaphoid.

• As vascular compromise progresses,intraluminal bleeding may occur and blood is often passed per rectum.

• Crampy abdominal pain is common.

Acute duodenal obstruction

• An infant or newborn usually presents withforceful, bilious vomiting.

• Abdominal distention may or may not bepresent.

• The obstruction may be complete or incomplete, so meconium or stool may havebeen passed.

• Jaundice may be seen.

Radiologic Diagnosis of Abnormalities ofRotation and Fixation

Normal position and fixation of Duodenum

Abnormal findings include positioning of the duodenojejunal flexure to the right of the spine, obstruction of the duodenum, and the “coil spring,” “corkscrew,” or “beak” appearance of the obstructed proximal jejunum

“Double bubble” in duodenal obstruction

Ultrasound• Reversal of the normal anatomic relationship between the SMA and SMV.

• “whirlpool sign” - midgut volvulus

The superior mesenteric vein (SMV) should be positioned to the right of the SMA, especially the first 3 cm distal to its origin.Reversal of SMA/SMV relationship is classically associated with intestinal malrotation

Reversal of SMA and SMV Whirlpool sign

TreatmentAim of treatment- Reduce the recurrence ofvolvulus, not the position.

Preoperative preparation• Aggressive resuscitation with fluid &electrolyte.• Intravenous broad spectrum antibiotics.• Taken to the operating room for immediateexploration.• Placement of a Nasogastric tube

Surgery (Ladd’s procedure)

2nd look operation is usually performed whenthere are multiple areas of bowel ofquestionable viability, when the entire midgutappears nonviable, or when clinical signs &symptoms suggest progressive loss ofintestine

Post operative care• Nasogastric decompression• Total parenteral nutrition until return of bowelfunction.

Complications• Diarrhea & dehydration in short bowel syndrome• Postoperative intussusception• Postoperative adhesion• Recurrent volvulus

any questions?