Morphological and hemodynamical alterations in brachial artery and cephalic vein. An image‐based study for preoperative assessment for vascular access creation

The current study aims to computationally evaluate the effect of right upper arm position on the geometric and hemodynamic characteristics of the brachial artery (BA) and cephalic vein (CV) and, furthermore, to present in detail the methodology to characterise morphological and hemodynamical healthy vessels. Ten healthy volunteers were analysed in two configurations, the supine (S) and the prone (P) position. Lumen 3D surface models were constructed from images acquired from a non-contrast MRI sequence. Then, the models were used to numerically compute the physiological range of geometric (n = 10) and hemodynamic (n = 3) parameters in the BA and CV. Geometric parameters such as curvature and tortuosity, and hemodynamic parameters based on wall shear stress (WSS) metrics were calculated with the use of computational fluid dynamics. Our results highlight that changes in arm position had a greater impact on WSS metrics of the BA by altering the mean and maximum blood flow rate of the vessel. Whereas, curvature and tortuosity were found not to be significantly different between positions. Inter-variability was associated with antegrade and retrograde flow in BA, and antegrade flow in CV. Shear stress was low and oscillatory shear forces were negligible. This data suggests that deviations from this state may contribute to the risk of accelerated intimal hyperplasia of the vein in arteriovenous fistulas. Therefore, preoperative conditions coupled with post-operative longitudinal data will aid the identification of such relationships

Haemodynamics and flow modification stents for peripheral arterial disease:a review

Endovascular stents are widely used for the treatment of peripheral arterial disease (PAD). However, the development of in-stent restenosis and downstream PAD progression remain a challenge. Stent revascularisation of PAD causes arterial trauma and introduces abnormal haemodynamics, which initiate complicated biological processes detrimental to the arterial wall. The interaction between stent struts and arterial cells in contact, and the blood flow field created in a stented region, are highly affected by stent design. Spiral flow is known as a normal physiologic characteristic of arterial circulation and is believed to prevent the development of flow disturbances. This secondary flow motion is lost in atheromatous disease and its re-introduction after endovascular treatment of PAD has been suggested as a method to induce stabilised and coherent haemodynamics. Stent designs able to generate spiral flow may support endothelial function and therefore increase patency rates. This review is focused on secondary flow phenomena in arteries and the development of flow modification stent technologies for the treatment of PAD

Arthroscopic reduction and fixation of greater tuberosity fractures of the humerus

BackgroundThe optimal technique for the displaced greater tuberosity (GT) fractures remains unclear; those in favor of arthroscopic techniques emphasize on the feasibility of arthroscopic reduction and fixation, while others report that anatomic reduction and osteosynthesis of the fracture are optimal through open surgery. Therefore, we performed this study to evaluate the clinical results of arthroscopic fixation for displaced and/or comminuted GT fractures using a bridging arthroscopic technique.Materials and methodsWe studied the files of 11 patients (4 men, 7 women; mean age, 55 years; range, 28-74 years), with an isolated, displaced GT fracture treated with arthroscopic reduction and double-row suture anchor fixation technique from December 2016 to October 2018. All patients were operated at a mean time from their injury of 23 days (range, 1-85 days) using an arthroscopic technique. Any concomitant pathology that was arthroscopically identified was identified and repaired after arthroscopic fixation of the GT fracture. The mean follow-up was 12 months (range, 6-18 months). We evaluated pain using a 0-10 point visual analog scale (VAS), shoulder range of motion, fracture healing, Constant-Murley Shoulder Outcome Score, and patients' satisfaction from the operation.ResultsPostoperative radiographs showed anatomic reduction without any displacement of the GT fracture in eight patients and residual displacement of<3 mm in three patients. All patients significantly improved in VAS score from 8.4 points (range, 7-10 points) preoperatively to 0.9 points (range, 0-3 points) postoperatively. Range of motion was 153 degrees forward flexion (range, 130-170 degrees), 149 degrees abduction (range, 120-170 degrees), 42 degrees external rotation (range, 20-70), and internal rotation between T10 and L3 spinal level. The final mean Constant-Murley Shoulder Outcome Score was 85.8 points (range, 76-94 points); correlation analysis showed that the patients with the higher greater tuberosity fracture displacement had the worst postoperative score (Pearson correlation coefficient -0,85; p=0.0009), and the patients with nonanatomic reduction had close to average score. All patients were very satisfied with the end result of the operation, even the 3 patients with residual fracture displacement. No patient experienced any postoperative complications.ConclusionsArthroscopic reduction and fixation of displaced GT fractures is a feasible minimally invasive procedure for optimal fracture healing and patients satisfaction