Radiological Diagnosis

Type IIIa Malrotation With Ladd's Band And Partial Obstruction Of The Duodenum

Supine AP view [Figure - 1] of the barium meal follow through study shows the misplaced duodeno-jejunal flexure, which is to the right of the Lumber spine. Subsequent AP view in standing position [Figure - 2] shows distension of the stomach and duodenum. There is incomplete obstruction of the duodenum more towards the third and fourth parts, with evidence of tapering at the level of the obstruction suggestive of an extrinsic compression. The jejunal loops appear normal. There is no "cork screw" or "twisted ribbon" appearance suggestive of volvulus. Supine AP view of ileoceacal region [Figure - 3] shows the ceacum and ileocecal junction in the right hypochondrium close to the midline. The ascending colon is in the umbilical region and the remainder of the colon is on the left side.

Patient was operated and our findings were confirmed per operatively. On laparotomy, the small bowel loops were collapsed but viable. There was no volvulus. The ceacum was in the right hypochondrium. The Ladd's band was cut and released.

Discussion

It is not the malrotation that causes the problem, but the associated abnormal mesenteric fixation of gut. This results in volvulus around superior mesenteric artery and vein, which can cause ischemic gangrene of entire small bowel.

Most cases of malrotation present at Neonatal period. It results in high intestinal obstruction. Volvulus is main cause of mortality in this age group. Small number of cases present after neonatal period. In this age group diagnosis may be unsuspected. Child presents with intermittent Vomiting. In malrotation, the obstruction by volvulus has to be ruled out since it is associated with high mortality. Obstruction occurs less commonly secondary to duodenal bands or an internal hernia. Duodenal bands arise from the posterior abdominal peritoneum and extend from the liver to the colon, passing anterior to the duodenum. Usually the distal descending or the third and fourth parts of the duodenum are obstructed. These bands are usually referred to as Ladd's bands [1].

Imaging studies are helpful in diagnosis and indicating complication of malrotation. Plain X-ray abdomen is useful in diagnosing intestinal obstruction. Barium studies like BMFT and barium enema are useful in identifying the position of dudeno-jejunal flexure and ceacum. Cross sectional imaging studies are primarily indicated in detecting blood flow in superior mesenteric vessels and detecting complication like volvulus. The clinical diagnosis of midgut volvulus in adolescents and adults is difficult because the presentation is usually nonspecific. Recurrent episode of vomiting with pain over period of months or years are typical and may lead to diagnosis. [2] Diarrhoea and malabsorption may also occur.[3] Barium study shows typical signs of volvulus like cork-screw sign or twisted ribbon appearance. On CT scan there is presence of whirlpool sign.

Other anomaly associated with malrotation are loss of normal relationship between superior mesenteric artery and vein. It may show vertical relationship or left to right inversion.[2],[4] Pancreas may reveal underdeveloped or absent uncinate process.

Mid-gut malrotation can be classified into three types according to the three stages of normal rotation - Types I, II and III. Type I malrotation or nonrotation is an error in rotation before 6 weeks of gestational age. The duodenum and the large bowel stop rotating after their first 90 degrees counter-clockwise rotation, so the proximal small bowel including the duodeno-jejunal junction lie on the right and the ceacum lies on the left. It is usually associated with good fixation so chances of volvulus is less. Radiology cannot differentiate from those that are fixed well from those that are not. Type II malrotation or duodenal malrotation occurs with an error in rotation between six and ten weeks of gestational age. The abnormality affects primarily the duodenum because this is the only portion of the bowel rotating at this time. [5,8] It may mimics appearance of duodenal atresia. This type is rare [5],[6]. In type IIA there is non-rotation of duodenum only and in typeIIB there is reverse rotation of duodenum and colon. An error in rotation after ten weeks of gestational age is results in Type III malrotation. The duodenum has 90 degrees of rotation remaining to complete and the large bowel has 180 degrees left. In Type III A, on barium study, there is either a complete or incomplete obstruction from Ladd's bands or volvulus. The duodeno-jejunal junction and ceacum are malpositioned, often lying in the midline [5]. This is the most dangerous type of malrotation. Volvulus, gangrene and death are common [5],[7]. Type III B is incomplete fixation of the hepatic flexure, type III C is incomplete fixation of the ceacum and Type III D is an internal hernia at the ligament of Trietz.