Abstract: Aim. Recently, several hypotheses on varicose veins origin were proposed. Accordingly, a non-saphenous foam procedure was shown to achieve successful results in the suppression of the sapheno-femoral reflux, being its persistence limited to a small percentage of treated cases. The aim of the present note is to illustrate the hemodynamic basis of these reflux suppressing failures.
Methods. Two hemodynamic theoretic simulations were designed to represent adequately this hemodynamic condition. The sapheno-femoral reflux can be classified according to Teupitz into two kinds of different shunts: ShI and ShIII. The ablation of the varicosity's of the non-saphenous superficial network can achieve the disconnection of Sh III and VI, but in no way of Sh I. So that, if the main reflux is a ShI the sapheno-femoral reflux does not disappear after the phlebectomy.
Results. The thorough study of the patient's cartography makes the choice of the surgical strategy easier and more precise.
Conclusion. Depending on the structure of the reflux and as to immediate results, GSV ablation can sometimes solve completely the varicose pathology, while in other cases it is completely unsatisfying.
Abstract: The Sclerosing Foam and Patent Foramen Ovale on-line Event was held on the Internet from February 12th to 23rd, 2007. Participation was organised in two groups: the Vascular Experts Panel and the Participants. An electronic Survey was submitted to the Foam_PFO/Vasculab Communities. M.V. Forlee, whose paper was submitted for discussion, thoroughly detailed his clinical case. The reported event is very rare and essentially does not affect Ultrasound-Guided-Sclerotherapy practice. However, if PFO-screened, the patient could have been selected for an alternative venous surgery. Data on collateral effects are inconsistent. In many series they are practically absent, while in others a high incidence decreases by using preventive procedures after UGS. In a simple experimental protocol Bergan shows their disappearance after leg elevation, compared to supine leg position (P<0.000299). However, others have practically no collateral effects without leg elevation or using high quality foam or physiological gas mixtures. The following procedures were considered a complete preventive set: leg elevation (10'), avoid patient dressing or putting on shoes/stockings by-himself, avoid Valsalva and constipation. Patient selection can easily be introduced into daily practice through anamnesis, alternative surgical solutions and preventive measures, eventually adding a screening/monitoring procedure and high-quality foam. Foam UGS is very safe and effective in treating varicose veins. Well conducted studies are needed to make reliable comparisons with alternative treatment methods.
Abstract: Aim. Recently, an intrasegmentary saphenous reflux was claimed to be due to the aspirating power of the capacitance of an incompetent small accessory vein (the reservoir). The present note outlines a more elementary explanation. A simplified model is digitally rendered, to show an Input-Output open path ShIIB with an intrasegmentary great saphenous vein (GSV) reflux.
Methods. Cutting the reservoir provides a flow inversion in the GSV trunk with reflux suppression.
Results. The analysis of the circuit shows how this result can be achieved even studying only the topographical properties of the venous circuit, without making any hypothesis on the vessel diameters or compliance.
Conclusion. This is an application of the Ockham's Razor (XIV century) and of the MEV analysis, based on the modern graph theory. The results of this simulation strongly support the hypothesis that the reservoir is not involved in the origin of the reflux.
Abstract: The purposes of this study were (1) to develop two computational methods and (2) to compare their performance (i.e. the accuracy and the time demand) in determining instantaneous stability, i.e., the shortest distance from an instantaneous center of mass (COM) state to all interpolated points on the stability boundary in the COM position-velocity state space. The intuitive numerical method interpolated the stability boundary against backward balance loss based on four sets of discrete boundary values with a spline function and a preset step size (Deltax). Then a brute-force search approach was used to determine this shortest distance. The analytical method used quadratic polynomial functions to represent the boundaries. The stability was then determined by using the Lagrange multiplier method to find the optimum for the analytical expression of the distance from this given COM state to the boundary. Because reducing Deltax can supposedly improve the accuracy of spline fitting, we used this approach to establish the benchmark employed to determine the accuracy level of all other computations. Based on the results from a database of 67 sit-to-stand-slip trials and 687 gait-slip trials, we would recommend the numerical method with Deltax=0.1 to reach an adequate accuracy level of 10(-2). By changing one order of Deltax from 0.1 to 0.01, however, the accuracy level improved drastically from 10(-2) to 10(-4). Nonetheless to achieve the same higher accuracy at a faster computing speed, we would recommend the analytical method, which costs 80% less time than the numerical approach at the accuracy level of 10(-4).
Abstract: The authors present clinical and instrumental results of N. 543 operations executed by CHIVA system. These cases are the result of trial performed in seven SIOC (Italian Society of CHIVA Operators) centers executed from November '87 to July '89. Functional and aesthetic results had been very good on over 85% of all cases; superficial thrombosis were verified on 10% of all cases but almost completely asymptomatic. The aa. propose to start a deeper trial on 500 patients choose by rigorous criteria of inclusion.
