Evaluation of the portal vein after duodenoduodenostomy for congenital duodenal stenosis associated with the preduodenal superior mesenteric vein, situs inversus, polysplenia, and malrotation.

A male infant weighting 2970 g with total situs inversus, polysplenia, malrotation, duodenal stenosis, and complex cardiac anomalies, was admitted to our hospital. At 4 days of age, he underwent surgery that revealed a blood vessel passing over the duodenum from the mesenterium to the porta hepatis. A loose overbridging duodenoduodenostomy was performed to prevent compression of the vessel. The cardiac anomalies were corrected, and he could eat unrestricted diets. At the age of 1 year and 3 months, a 3-dimensional computed tomographic scan demonstrated that the vessel on the duodenum was the superior mesenteric vein (SMV), and it formed the portal vein with the splenic vein at the porta hepatis. Further, the scan revealed no compression of the SMV at the anastomosis. Doppler ultrasonography revealed a normal portal blood flow of 118.6 mL/min. This report describes the junction between the SMV and the splenic vein in a patient who had the SMV passing over the duodenum from the mesenterium. Correctly, patients previously diagnosed with a preduodenal portal vein could have a preduodenal SMV. The loose overbridging duodenoduodenostomy had advantages not only in passage of the anastomosis but also in maintenance of the portal blood flow for the congenital duodenal obstruction with the preduodenal SMV.