Superior mesenteric arteriovenous fistula (SMAVF) is an extremely infrequent vascular disorder. It is characterized by abnormal, direct communication between high-pressure superior mesenteric artery (SMA) and low-pressure superior mesenteric vein (SMV). This shunt allows blood to bypass the intestinal capillary bed and produces hypertension in the portal circulation. Although SMAVF can be congenital, the majority of cases reported have been due to abdominal trauma or iatrogenic causes. These fistulas originate from an undetected injury to SMA and SMV and can present several days to several years later, usually following bowel-related surgery. Manifestations of SMAVF include a wide variety of symptoms such as mild abdominal pain, diarrhea and weight loss. Due to the often obscured presence of the fistula, complications related to long-standing arteriovenous (AV) shunt and high portal blood pressure are potentially fatal. The most serious complications are congestive heart failure and portal hypertension, which may lead to gastro-esophageal variceal bleeding (1). General mortality for untreated cases of portal arteriovenous fistula (AVF) is estimated at about 26% (2). Here, we report a case of delayed presentation of acquired SMAVF in a male adult after small bowel resection.

We describe a method for dual-view biomechanical strain measurements of highly asymmetrical biological objects, like teeth or bones. By using a spherical mirror, we were able to simultaneously record a digital hologram of the object itself and the mirror image of its (otherwise invisible) rear side. A single laser beam was sufficient to illuminate both sides of the object, and to provide a reference beam. As a result, the system was mechanically very stable, enabling long exposure times (up to 2 min) without the need for vibration isolation. The setup is simple to construct and adjust, and can be used to interferometrically observe any object that is smaller than the mirror diameter. Parallel data processing on a CUDA-enabled (compute unified device architecture) graphics card was used to reconstruct digital holograms and to further correct image distortion. We used the setup to measure the deformation of a tooth due to mastication forces. The finite-element method was used to compare experimental results and theoretical predictions.

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