During normal abdominal development, the 3 divisions of the GI tract (ie, foregut, midgut, hindgut) herniate out from the abdominal cavity, where they then undergo a 270º counterclockwise rotation around the superior mesenteric vessels. Following this rotation, the bowels return to the abdominal cavity, with fixation of the duodenojejunal loop to the left of the midline and the cecum in the right lower quadrant.
Intestinal malrotation, also known as intestinal nonrotation or incomplete rotation, refers to any variation in this rotation and fixation of the GI tract during development. Interruption of typical intestinal rotation and fixation during fetal development can occur at a wide range of locations; this leads to various acute and chronic presentations of disease. The most common type found in pediatric patients is incomplete rotation predisposing to midgut volvulus, requiring emergent operative intervention.[1, 2]
The first reports of intestinal malrotation were based on surgical and autopsy findings and occurred prior to 1900; however, the first description of the embryologic process of intestinal rotation and fixation was not published until 1898. In 1923, Dott was the first to describe the relationship between embryologic intestinal rotation and surgical treatment. In 1936, William E. Ladd wrote the classic article on treatment of malrotation. His surgical approach, now known as the Ladd procedure, remains the cornerstone of practice today.
Intestinal malrotation occurs due to disruption of the normal embryologic development of the bowel. Understanding of normal abdominal development aids in the understanding of the etiology of the clinical findings seen with malrotation.
The alimentary tract develops from the embryologic foregut, midgut, and hindgut. Normal rotation takes place around the superior mesenteric artery (SMA) as the axis. It is described by referring to 2 ends of the alimentary canal, the proximal duodenojejunal loop and the distal cecocolic loop, and is usually divided into 3 stages. Both loops make a total of 270° in rotation during normal development. Both loops start in a vertical plane parallel to the SMA and end in a horizontal plane. See the image below.
Normal rotation of the intestines during development. The superior mesenteric artery (SMA) is the axis. The duodenojejunal loop (red arrow) begins sup....
Stage I occurs between 5-10 weeks' gestation. It is the period of physiologic herniation of the bowel into the base of the umbilical cord. The duodenojejunal loop begins superior to the SMA at a 90° position and rotates 180° in a counterclockwise direction. At 180°, the loop is to the anatomical right of the SMA, and by 270°, it is beneath the SMA. The cecocolic loop begins beneath the SMA at 270°. It rotates 90° in a counterclockwise manner and ends at the anatomical left of the SMA at a 0° position. Both loops maintain these positions until the bowel returns to the abdominal cavity. Also during this period, the midgut lengthens along the SMA, and, as rotation continues, a broad pedicle is formed at the base of the mesentery. This broad base protects against midgut volvulus.
Arrest in development at stage I results in nonrotation. Subsequently, the duodenojejunal junction does not lie inferior and to the left of the SMA, and the cecum does not lie in the right lower quadrant. The mesentery in turn forms a narrow base as the gut lengthens on the SMA without rotation, and this narrow base is prone to clockwise twisting leading to midgut volvulus. The width of the base of the mesentery is different in each patient, and not every patient develops midgut volvulus.
Stage II occurs at 10 weeks' gestation, the period when the bowel returns to the abdominal cavity. As it returns, the duodenojejunal loop rotates an additional 90° to end at the anatomical left of the SMA, the 0° position. The cecocolic loop turns 180° more as it reenters the abdominal cavity. This turn places it to the anatomical right of the SMA, a 180° position.
Stage II arrest results in incomplete rotation and is most likely to result in duodenal obstruction. Typically, peritoneal bands running from the misplaced cecum to the mesentery compress the third portion of the duodenum. Depending on how much rotation was completed prior to arrest, the mesenteric base may be narrow and, again, midgut volvulus can occur. Internal herniations may also occur with incomplete rotation if the duodenojejunal loop does not rotate but the cecocolic loop does rotate. This may trap most of the small bowel in the mesentery of the large bowel, creating a right mesocolic (paraduodenal) hernia.
Stage III lasts from 11 weeks' gestation until term. It involves the descent of the cecum to the right lower quadrant and fixation of the mesenteries.
Potential hernial pouches form when the mesentery of the right and left colon and the duodenum do not become fixed to the retroperitoneum. If the descending mesocolon between the inferior mesenteric vein and the posterior parietal attachment remains unfixed, the small intestine may push out through the unsupported area as it migrates to the left upper quadrant. This creates a left mesocolic hernia with possible entrapment and strangulation of the bowel. If the cecum remains unfixed, volvulus of the terminal ileum, cecum, and proximal ascending colon may occur.
Intestinal malrotation occurs in between 1 in 200 and 1 in 500 live births.[6, 7] However, most patients with malrotation are asymptomatic, with symptomatic malrotation occurring in only 1 in 6000 live births. Symptoms and diagnosis may occur at any age, with some reports of prenatal diagnosis of intestinal malrotation.
Malrotation may occur as an isolated anomaly or in association with other congenital anomalies; 30-62% of children with malrotation have an associated congenital anomaly. All children with diaphragmatic hernia, gastroschisis, and omphalocele have intestinal malrotation by definition. Additionally, malrotation is seen in approximately 17% of patients with duodenal atresia and 33% of patients with jejunoileal atresia.[10, 11]
Data from recent series reveal that mortality rates in adults and children operated on for intestinal malrotation range from 0-14%. Higher mortality rates are seen in cases with acute onset of midgut volvulus, delayed diagnosis, or the presence of intestinal necrosis.[12, 13, 14, 15, 1, 16] Children with other associated anomalies also have higher overall mortality rates. A report of 25 years' experience demonstrated congenital cardiovascular disease in 27.1% of patients with intestinal malrotation; those patients had a morbidity rate of 61.1% after intestinal malrotation surgery.
Male predominance is observed in neonatal presentations at a male-to-female ratio of 2:1. No sexual predilection is observed in patients older than 1 year.
Traditional teaching suggests that as many as 40% of patients with malrotation present within the first week of life, 50% in the first month, and 75% in the first year. However, more recent series have shown that malrotation is increasingly identified in adults. A series of 170 patients with intestinal malrotation diagnosed at a single institution between 1992-2009 found that 31% were infants, 21% were aged 1-18 years, and the remaining 48% were adults. A second series found that 42% of patients with malrotation were adults.
Intestinal malrotation can present as either an acute or chronic process. Additionally, various types of rotational defects are recognized. The history of present illness varies depending on these different factors.
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Physical examination findings may vary depending on the type of rotational defect as well as whether the symptoms are chronic or acute in onset.
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The following studies may help facilitate the diagnosis and guide treatment in patients with suspected intestinal malrotation:
An elevated or decreased WBC count may indicate systemic inflammation and/or sepsis.
Thrombocytopenia may indicate a platelet consumptive process (eg, necrotizing enterocolitis); additionally, platelets are an acute phase reactant with thrombocytosis indicating systemic inflammation.
A decreased hemoglobin/hematocrit gives evidence of blood loss, possibly through GI bleeding.
Metabolic acidosis provides evidence for ongoing ischemia as observed with necrotizing enterocolitis or strangulated bowel (volvulus). This is demonstrated on serum laboratory studies with an elevated lactate and/or base deficit
Patients with volvulus and resultant bowel ischemia can develop severe metabolic derangements, which should be corrected, if possible, prior to operative intervention.
Ongoing sodium, chloride, and bicarbonate losses can occur through suctioned GI secretions.
Hyperkalemia may occur secondary to metabolic acidosis and hemolysis.
These may be useful to rule out other infectious causes if the differential remains unclear.
A current type and screen must be available because these patients often require emergent operative intervention which may or may not require blood transfusion.
These should be obtained in patients with sepsis, if ongoing blood loss is a concern and prior to operative intervention.
The following imaging studies may be helpful in clarifying the diagnosis:
Plain radiography has limited use for defining intestinal obstruction. The classic pattern for duodenal obstruction, if present, is the double-bubble sign produced by an enlarged stomach and proximal duodenum with little gas in the remainder of the bowel. Distended bowel loops with or without pneumatosis intestinalis may be seen. If pneumoperitoneum is suspected, a left lateral decubitus film can be obtained to better visualize this process
Upper GI series is the criterion standard to diagnose intestinal malrotation, with a sensitivity of 93-100%. However, upper GI but should only be obtained in patients who are hemodynamically stable.[22, 23, 24]
Normal rotation is present if the duodenal C-loop crosses the midline and places the duodenojejunal junction to the left of the spine at a level equivalent or superior to the pylorus. If the contrast ends abruptly or tapers in a corkscrew pattern, midgut volvulus or some other form of proximal obstruction may be present. Barium is the contrast of choice in patients who are stable or have chronic symptoms
Contrast studies may not be possible in patients who are actively vomiting or are otherwise unstable and need immediate surgical exploration. Water-soluble agents should be used if the study must be performed prior to emergent operative intervention. See the image below.
In this upper GI series with abnormal results, the duodenum does not cross the midline, and the small bowel is present only in the right side of the a....
In this upper GI series with abnormal results, the duodenum does not cross the midline, and the small bowel is present only in the right side of the abdomen.
Occasionally, upper GI series may fail to define the location of the duodenojejunal junction, in which case, a contrast enema may be helpful to identify the location of the cecum.
A normally placed cecum does not unequivocally rule out intestinal malrotation and clinical judgment must be exercised. See the image below.
These 2 lower GI series show the cecum (arrows) in the right upper quadrant, indicative of malrotation.
Ultrasonography is quickly becoming a useful imaging modality in infants and children with abdominal pain and has been used to accurately diagnose intestinal malrotation with or without midgut volvulus.[25, 26]
In the hands of experienced ultrasonographers, ultrasonography has been shown to have false positive rate of 0% and a false negative rate of 0-30%.[27, 28]
Findings indicative of malrotation include inversion of the superior mesenteric artery (SMA) and the superior mesenteric vein (SMV) and a retroperitoneal position of the duodenum after fluid bolus via a nasogastric tube.
Other diagnostic findings include fixed midline bowel loops and duodenal dilation with distal tapering. The finding of the SMV coiled around the SMA is suggestive of intestinal volvulus The presence of ascites and thickened bowel wall were not found to be statistically significant predictors of malrotation with midgut volvulus
CT scanning is not well developed for diagnosing malrotation and midgut volvulus.
Scattered case reports of its use are noted, but it is not recommended as the principal diagnostic tool.
The following procedures may be helpful:
Insert an NG tube in all patients with bilious emesis and suspected malrotation.
Adjust the NG tube to low intermittent suction in order to decompress the bowel proximal to any obstruction that may be present.
Most patients require long-term intravenous access after surgery, especially if midgut volvulus is present.
Because intravenous nutrition is likely to be necessary, central line access is preferable over peripheral access so that parenteral nutrition can be delivered.
Medical care of intestinal malrotation is directed toward stabilizing the patient.
Where malrotation with volvulus or obstruction is suspected, seek immediate pediatric surgical consultation. Maintain patients on nothing by mouth (NPO) and adjust NG or orogastric tube to low intermittent suction. Correct fluid and electrolyte deficits. All patients require intravenous resuscitation with physiologic salt solution. Administer broad-spectrum antibiotics prior to surgery, if possible.
If a patient has signs of shock, administer appropriate fluids, blood products, and vasopressor medications to improve hypotension. Dopamine is often used as first-line therapy because of its possible effects to increase splanchnic blood flow. Dopamine can be started at an infusion rate of 3 mcg/kg/min intravenously (IV) and continued postoperatively even if the patient is not hypotensive.
Most patients require long-term intravenous access after surgery, particularly if midgut volvulus is present. Additionally, intravenous nutrition is likely to be necessary. For this reason, central venous catheters should be placed in most patients.
If the patient is unstable, do not delay surgical intervention for upper GI and laboratory studies. Quick surgical intervention, not prolonged medical management, is associated with the best results if midgut volvulus is suspected.
The Ladd procedure remains the cornerstone of surgical treatment for malrotation today. Prior to William Ladd's publication in 1936, surgical treatment for malrotation with or without volvulus had a mortality rate higher than 90%. In fact, at Ladd's own institution, the mortality rate was 100% before the development of his new technique. A classic Ladd procedure is described as reduction of volvulus (if present), division of mesenteric bands, placement of small bowel on the right and large bowel on the left of the abdomen, and appendectomy. Published reports for laparoscopic Ladd procedure are now appearing in the literature as well.
If midgut volvulus is present, the entire small intestine along with the transverse colon is delivered out of the abdominal incision, where the volvulus can be reduced. Because the volvulus usually twists in a clockwise direction, reduction is accomplished by twisting in a counterclockwise direction. Complete detorsion usually requires 2-3 twists of the bowel. After the blood supply has been restored by detorsion, the surgeon must make a decision about viability of the involved bowel. The outcome is better when no gangrenous bowel is present or when a small, localized gangrenous segment is present, which can be resected and a primary anastomosis performed.
If multiple areas of questionable viability are present, many surgeons choose to leave the areas and perform a second-look operation in 12-24 hours if the patient is not showing clinical recovery. See the image below.
This patient had malrotation with midgut volvulus. The gut is darkened in color because of ischemia.
Grossly necrotic bowel should be resected. Primary anastomosis versus diversion of the fecal stream with a proximal ostomy should be performed at the surgeon’s discretion. Three principles should be used to guide decision making:
After the volvulus is reduced or if no volvulus was present, identify any extrinsic obstruction to the duodenum.
If peritoneal bands crossing the duodenum are found, ligate them with careful attention to protecting the superior mesenteric vessels. The bands may also obstruct the ileum or the jejunum and sometimes run to the gallbladder and liver.
Extrinsic obstruction may also be due to the cecum, colon, or superior mesenteric artery (SMA), impinging on the duodenum; relief is obtained by placing the cecum with its mesentery in the left upper quadrant and exposing the anterior duodenum through its entire length. After extrinsic obstruction has been relieved, determine that no intrinsic obstruction exists by passing an NG tube through the duodenum.
Appendectomy is performed during operation for malrotation for 2 reasons :
Use of a laparoscopic approach to the correction of malrotation is feasible (level III, level IV evidence) but long-term outcome data are lacking. An open approach is thought to create adhesions, thereby reducing the risk of recurrent volvulus. Critics of the laparoscopic approach cite that laparoscopy is associated with minimal adhesion formation and thus may not afford the patient comparable long-term benefit.
Laparoscopy has been used to repair malrotation in clinically stable patients with or without signs of duodenal obstruction without midgut volvulus.
The Ladd procedure, including widening of the mesenteric base and dissection of peritoneal bands, has been performed successfully using a laparoscopic approach and has resulted in shorter hospital length of stay.
Laparoscopic Ladd procedure is now accepted as an initial approach to surgical correction, with recent reports showing superior short-term results without any increase in operative duration.[33, 34, 35]
Some authors have reported on the success of single-incision laparoscopic Ladd procedure for intestinal malrotation without volvulus in adults.
A study reported that in children aged 6 months or older with suspicion of intestinal malrotation but not presenting with an acute abdomen or hemodynamically instability, laparoscopy should be considered as a first approach to diagnose and subsequently treat intestinal malrotation.
Patients with heterotaxy syndromes have increased rates of abnormalities of intestinal rotation. The approach to the management of these rotational abnormalities is controversial.
Some authors advocate for screening of all children with an upper GI study and elective correction of any rotational abnormality. However, a retrospective review of 29 children who underwent Ladd procedure revealed that the complication rate was 57% among patients with heterotaxy who were otherwise asymptomatic, compared with only 9% in the symptomatic, nonheterotaxy group. These authors recommend that asymptomatic children be managed conservatively with operative intervention reserved for those children who become symptomatic. A systematic review by Cullis et al found that out of 414 asymptomatic patients that had no screening for intestinal rotation, one patient developed malrotation symptoms which was confirmed by laparotomy.
Consultations with the following specialists may be helpful:
Feeding strategies are discussed under Further Inpatient Care.
Patients with short-bowel syndrome are at high risk for failure to thrive. These infants require frequent monitoring of growth parameters during the immediate postoperative period to ensure adequate weight, length, and head circumference gains.
Patients may develop iron, folate, and vitamin B-12 deficiencies due to malabsorption depending on how much bowel is resected.
Outpatient care should be individualized, depending on each patient’s operative and postoperative course.
Children with prolonged hospitalization may experience developmental delays and require aggressive physical, occupational, and speech therapy.
Infants can develop poor truncal control due to prolonged periods in the supine position while hospitalized, additionally they may develop contractures in the extremities, or feeding aversion due to prolonged periods with NG tubes in place and taking nothing by mouth.
Developmental delays should be monitored in both inpatient and outpatient settings and should be intervened upon as early as possible.
Immediate postoperative care in patients with intestinal malrotation includes the following:
Nutrition in the postoperative period is as follows:
Strategies to improve nutrition and considerations for short bowel syndrome are as follows:
All children suspected of having malrotation with or without midgut volvulus should be transferred to a facility with pediatric surgical support. Furthermore, any child with bilious emesis is assumed to have a surgical problem until proven otherwise.
Complications include the following:
In general, older children do better than infants. The presence of midgut volvulus prolongs hospitalization, and prognosis is based on how much bowel is preserved. Because of the morbidity involved with midgut volvulus, immediate referral for pediatric surgical care can improve outcome more than any other medical intervention.