Malrotation

Malrotation
Erica Davanian
  • First described around 1898, William Edwards Ladd standardized the evaluation and surgical management of malrotation in 1932.
  • The principles from Ladd’s landmark article and textbooks still hold true today.1,2
  • Although an open surgical technique is still used in most cases of malrotation, the first laparoscopic procedure was attempted in 1995 and has become more commonly used since that time.3,4
  • However, laparoscopic management is controversial for reasons discussed in the surgery section later in this chapter.
RELEVANT ANATOMY
  • Between the 4th and 10th weeks of gestation, normal development of the midgut proceeds via herniation through the umbilicus.
  • This involves a 90° counterclockwise rotation, retraction with 180° counterclockwise rotation, and fixation to the retroperitoneum.2,5
  • The superior mesenteric artery (SMA) and superior mesenteric vein (SMV) course through the root of the mesentery, acting as a fulcrum around which the embryologic intestine makes its total 270° counterclockwise rotation.
  • Ultimately, the SMA lies to the left of the SMV.
  • The duodenojejunal junction is fixated in the left upper quadrant (LUQ) by the ligament of Treitz.
  • The cecum is fixed to the retroperitoneum in the right lower quadrant (RLQ), within the right iliac fossa.2,5
  • The term “malrotation” encompasses a spectrum of disorders that occur when less than 270° of rotation is achieved during embryologic development resulting in abnormal location of the cecum and the duodenojejunal junction.
  • In the classic malrotation patient, the duodenojejunal junction lies to the right of the midline and the cecum lies to the left of the midline.
  • Additionally, a relatively long and narrow mesenteric root results as well as a peritoneal band that crosses from the right to left, from the cecum to duodenojejunal junction (Figure 25.1).2,5
Figure 25.1 Malrotation with volvulus. A, Normal small bowel mesenteric attachment (as demonstrated by the arrow). This prevents twisting of small bowel because of the broad fixation of the mesentery. B, Malrotation of colon with obstructing duodenal bands (arrow, shortened mesenteric attachment). C, Midgut volvulus around the superior mesenteric artery caused by the narrow base of the mesentery (arrow shows twisting of bowel). (Reprinted with permission from Stephenson SR. Diagnostic Medical Sonography. 3rd ed. Philadelphia, PA: Wolters Kluwer/Lippincott Williams & Wilkins; 2012.)
EPIDEMIOLOGY AND ETIOLOGY
  • The actual incidence of malrotation is estimated to be between 0.2% and 1% of the population but becomes symptomatic in approximately 1 of 2500 live births.3,5
  • There is no gender preponderance.
  • Etiology is thought to be multifactorial, as it is often associated with additional developmental abnormalities (eg, heterotaxy syndrome, congenital diaphragmatic hernias, anorectal malformations, duodenal webs, and intestinal atresias).2,5,6
  • Generally, presentation is early, with 75% of patients presenting within 1 month of age. The majority of the remaining patients present within their first year of age.2,5,6
CLINICAL PRESENTATION
  • Malrotation can present at any age and with a wide variety of symptoms of both acute and chronic nature.
  • Age often correlates to symptomology.
  • Bilious emesis is the most common presenting symptom in neonates with malrotation.
  • However, older children and adults have a broader spectrum of symptoms, most commonly abdominal pain, but also emesis, diarrhea, and nausea.6
  • Patients of any age can present with volvulus and acute abdomen.
  • In these patients, the abdomen is distended and peritonitic and the overlying skin may have erythema.
  • Patients will most likely have laboratory test results representative of metabolic acidosis.2
  • There is also a subset of patients who are diagnosed with malrotation incidentally or who only have mild symptoms that are not life altering.
  • These patients are generally not considered surgical candidates but must be educated on their disorder and instructed to seek emergency medical care if they begin to develop severe abdominal pain or if other symptoms worsen.6,7
  • Malrotation exists as a spectrum of rotational disorders and abnormal anatomic orientations from reversed rotation to paraduodenal hernias (Table 25.1).
  • The presentation is also dependent on the physical degree of malrotation.2,6
  • This variation of presentation may lead to delayed diagnosis, most often in older children and adults, so high clinical suspicion should always be maintained to avoid the devastating results of an undiagnosed volvulus.6
TABLE 25.1 Spectrum of Anatomic Variations Associated With the Term “Malrotation”

Rotational Abnormality

Anatomic Orientation

Associated Complications

Reversed rotation

90° clockwise rotation

Transverse colon to the right and dorsal to the SMA within a retroduodenal tunnel and within the small bowel mesentery

Volvulus with transverse colon obstruction

Nonrotation

Failure to rotate (0°)

Cecocolic limb at the left hemidiaphragm and duodenojejunal limb at the right hemidiaphragm

Midgut volvulus

Incomplete rotation

Arrested counterclockwise rotation at about 180°

Cecum at RUQ

Obstructing peritoneal bands

Mesocolic/paraduodenal hernias

Normal rotation (270°)

Failure of the right and left mesocolon to fuse with the posterior body wall creating a potential space

Small bowel sequestration and obstruction within aberrant potential space

RUQ, right upper quadrant; SMA, superior mesenteric artery.

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May 5, 2019 | Posted by in PEDIATRICS | Comments Off on Malrotation

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