Based on the position of the third portion of the duodenum at sonography, it is not possible to confidently diagnose malrotation.

Abstract

Listen

Translate article

Sir, There are major ethical, methodological and conclusions flaws in the study by Hennessey [1] on the use of ultrasound in diagnosis of malrotation based on the position of the duodenum. There is no justification for using US as the primary imaging for evaluation of malrotation without strong evidence that it has at least the same accuracy as an upper gastrointestinal contrast study (UGI). The position of the duodenum behind the superior mesenteric vessels does not exclude malrotation [2]. The duodenum can be behind the superior mesenteric artery in patients with malrotation (Fig. 1) and it is sometimes difficult to differentiate between the duodenum and a jejunal loop that is crossing behind the superior mesenteric artery (Fig. 2). The methods in the Hennessey [1] study are seriously flawed. The number of children with malrotation is very small, there are no clear criteria for the initial selection of US or UGI for evaluation of malrotation, and the method of follow-up is not specified. There is no gold standard. The authors’ claim that they had no false-negative studies cannot be made. Only 9 of the 114 children with negative sonograms had UGI studies. The claim that “No child with normal ultrasound needed surgery” cannot be made as proof of no malrotation. Patients with malrotation can have only mild or no symptoms and midgut volvulus can occur at any time during life. The technique of giving oral water to facilitate visualization of the duodenum was not helpful in the management in any of the seven patients with malrotation. Three of these seven patients were called equivocal by US and diagnosed by UGI. Based on Table 1 in Hennessey et al. [1], an abnormal duodenum was observed in only one patient; this patient also had volvulus with a whirlpool sign, which makes the diagnosis of midgut volvulus from malrotation obvious [3]. The use of US can lead to delay in diagnosis in some patients. The longest time period from US to UGI in patients with equivocal findings was 77 days. In addition, 9 of 21 children with equivocal US were assumed to be normal without UGI. It is impossible to know how many of them had a false-negative sonogram. The authors argue in favor of US as compared to UGI study because of the ionizing radiation associated with the UGI study. There is a consensus that if appropriately used, the benefit of any imaging using ionizing radiation exceeds by far the potential risk of radiation, which is grossly estimated to be equivalent to 1 year of background radiation exposure [4]. I suggest that the practice performed by the authors and their false message of the safe and accurate use of US in evaluation of malrotation carries much higher risk to the patients than any radiation.