Callus has been identified as a risk factor leading to severe diabetic foot ulcer; thus, it is necessary to prevent its formation. Callus formation under the first, second, and fifth metatarsal heads (MTHs) is associated with external forces (pressure and shear stress) during walking. However, the gait factors increasing the external forces remain undetermined. Thus, this study aims to identify the factors increasing the external forces to prevent callus formation. In 59 patients with diabetic neuropathy wearing their usual shoes, the external forces, and the lower extremity joint angles were measured using MEMS force sensors and motion sensors. The external forces and their relationship with the lower extremity joint angles and footwear size were determined. Risk factors causing high external forces on the first MTH included small flexion of the knee joint (p = 0.015) and large ankle pronation motion (p = 0.034) to obtain propulsion. For the second MTH, wearing excessively long footwear was identified (p = 0.026). For the fifth MTH, high external force was related to tight width footwear (p = 0.005). An effective intervention for preventing callus formation for the first MTH would involve assisting the push-off foot motion using rocker-sole footwear or gait training. For the second and fifth MTHs, wearing appropriate size footwear would be effective.

We investigate the flow past two transcatheter aortic valves (TAVs) and one severely calcified valve in an anatomically realistic aorta geometry to evaluate the ability of the TAVs to establish a healthier aortic flow compared to a diseased case. Velocity measurements of pulsatile flow are carried out using the 3D-particle tracking velocimetry technique. We present a novel approach based on the Smagorinsky model to assess the important subvoxel-scale (here smaller than 750 [Formula: see text]m) shear stress contribution that is usually unavailable in experiments. Both TAV models feature a small retrograde flow of about 5% of the stroke volume and a lower number of coherent vortical structures. Turbulence past the TAVs is strongly suppressed as evidenced by the lower levels of turbulent kinetic energy even though the newer generation TAV performs better than the old one. Also lysis indices are substantially reduced in both models. The new generation TAV displays a slightly higher risk for thrombogenicity due to longer exposure times. We anticipate that our new approach to include turbulence and shear stress related quantities may help to validate the design of cardiovascular devices.

BACKGROUND: It has been reported that median arcuate ligament syndrome is closely associated with gastric or pancreaticoduodenal artery aneurysms. Hemodynamic state plays an important role in the formation of the aneurysms. These aneurysms are treated with open resection or endovascular exclusion. However, whether revascularization of the celiac artery can prevent the aneurysm formation is unknown. This report indicated a possibility that prophylactic revascularization for celiac artery stenosis resulted in decreased shear stress on the collaterals, which may otherwise be susceptible to new aneurysms.
METHODS: This report describes a 51-year-old man who presented with epigastric pain at our hospital. According to contrast enhanced computed tomography (CT), he was diagnosed with a ruptured right gastric artery aneurysm and celiac artery stenosis caused by the median arcuate ligament (MAL). He had a vascular anomaly of the common hepatic artery arising from the superior mesenteric artery (SMA). His vital signs were stable. We informed him of the situation and he chose open surgery rather than endovascular treatment. Following, we resected the aneurysm and transected the MAL. Intraoperative angiography after transection of the MAL showed the antegrade blood flow to the splenic artery instead of the retrograde flow via the prominent collaterals. Follow-up CT confirmed narrowed collateral vessels between the SMA and the celiac artery without de-novo aneurysms.
CONCLUSIONS: While the necessity of celiac artery release could be questioned, the present case supports the hemodynamic benefits of MAL transection in terms of de-novo aneurysm prevention.