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A Comparison between the Mechanical Behaviour of Steel Wires and Ultra High Molecular Weight Poly Ethylene Cables for Sternum Closure

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Materials Sciences and Applications 2011年第10期2卷 1367-1374页

作者： Roelof Marissen Mischa Nelis Mildred Janssens Michelle D. M. E. Meeks jos g. maessen 不详

Sternum closure after open heart surgery is typically done with steel wires. Final approximation of sternal parts and connection is achieved by twisting the ends of the wire and bending the twisted assembly towards the sternum in order to minimize outward protrusion. Though this routine procedure is highly effective, some failures do occur, e.g. due to wire fracture. Fatigue fracture of the wires, e.g. due to coughing implies a failure risk. An alternative development is to make cables from gel spun Ultra High Molecular Weight Poly Ethylene (UHMWPE) fibres, such fibres are extremely strong, yet flexible, and if made as a very pure grade, they are highly bio compatible. The optimal connection technique will be different from that of steel. Connection will rather be with knotting than twisting. A new sternum closure and fixation technique has been developed for the sternum. Additionally, a testing technique was developed, for a connection of simulated sternum parts, using different materials according to their respective optimal connection method and subsequently testing the mechanical properties of the connection. Substantial differences were observed. The mechanical behaviour of twisted steel wire connection showed more scatter than the knotted UHMWPE cables and some initial slack was sometimes present in the twisted cables. The maximum attainable force in the steel wires was determined by “untwisting” due to the external load. The maximum force in the UHMWPE cables was determined by the knot strength, either slipping for small knots, or breaking of the cables at the knots for slip-improved knots. The maximum force on the knotted UHMWPE cables was substantially larger than the maximum force on the twisted steel wires. Fatigue tests were performed on both the steel solution and the UHMWPE cables solution. The performance was about similar, although the simulated sternum opening was smaller for the UHMWPE cables at higher load levels. Summarizing, the UHMWPE cables sh

关键词： Heart Surgery Load Displacement Fracture Deformation Twisting Knotting Slip Fatigue

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3D-echo in preoperative assessment of aortic cusps effective height

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World Journal of Cardiology 2014年第7期6卷 689-691页

作者： Jan Nijs Sandro gelsomino Bastian BLJH Kietselaer Orlando Parise Fabiana Lucà jos g maessen Mark La Meir Cardiothoracic Surgery University Hospital1020 BrusselsBelgium Cardiothoracic Department Maastricht University Hospital6229 HX MaastrichtThe Netherlands

Effective height,which represents the height difference between the central free margins and the aortic insertion lines can be easily determined by 2-D echocardiography and allows for identification of prolapse in the native cusps and assessment of prolapse correction after valve ***,it allows to see only two of three aortic valve(AV)coaptation planes and this may lead to misunderstanding of the underlying pathophysiological mechanism for aortic regurgitation and hence in unsuccessful *** contrast,3D transoesophageal echocardiography and multiple plane reconstruction lets visualize all the three coaptation planes between the AV cusps and it represents an invaluable tool in the assessment of aortic valve *** is highly recommendable before AV repair to accurately study the complex three dimensional cusps anatomy and their geometric interrelation with aortic root.

关键词： Aortic valve Aortic repair Aortic prolapse Echocardiography

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心外膜高频刺激心脏植物神经节丛的时间累积和疲劳效应

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中国胸心血管外科临床杂志 2009年第5期16卷 403-405页

作者：汤敏 Mark La Meir 陈长志 jos g maessen 昆山宗仁卿纪念医院胸心外科江苏昆山215300 荷兰马斯特里赫特大学医院心血管中心上海交通大学医学院附属仁济医院心胸外科上海200127

目的观察术中经心外膜对心包内植物神经节丛行高频刺激(HFS)时出现的时间累积效应和疲劳效应,初步探讨其产生的原因和临床意义。方法对江苏昆山宗仁卿纪念医院收治的16例行心脏手术患者同期行同步HFS心脏植物神经节丛,刺激时程从50 ms... 详细信息

目的观察术中经心外膜对心包内植物神经节丛行高频刺激(HFS)时出现的时间累积效应和疲劳效应,初步探讨其产生的原因和临床意义。方法对江苏昆山宗仁卿纪念医院收治的16例行心脏手术患者同期行同步HFS心脏植物神经节丛,刺激时程从50 ms逐渐延长至100 ms及200 ms,观察P-R间期延长和房室传导阻滞的发生情况。结果16例患者中2例患者被排除,14例患者均在同步HFS时程为50 ms时出现P-R间期延长,100 ms时出现P-R间期进一步延长,200 ms时出现房室传导阻滞的时间累积效应;4例患者发生迷走效应出现后又再次消失的疲劳现象。结论术中经心外膜探查心脏植物神经节丛需重视迷走效应的时间累积和疲劳效应,提高神经节的检出率,并提高心房颤动消融的疗效。

关键词：高频刺激心脏植物神经节丛时间累积效应疲劳效应

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Unreliability of aortic size index to predict risk of aortic dissection in a patient with Turner syndrome

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World Journal of Cardiology 2014年第5期6卷 349-352页

作者： Jan Nijs Sandro gelsomino Fabiana Lucà Orlando Parise jos g maessen Mark La Meir Cardiothoracic Surgery University Hospital 1090 Brussels Belgium Cardiothoracic Department Maastricht University Hospital 6229 HX Maastricht The Netherlands Cardiothoracic Surgery University Hos-pital 1090 Brussels Belgium

Aortic size index(ASI) has been proposed as a reliable criterion to predict risk for aortic dissection in Turner syndrome with significant thresholds of 20-25 mm/m2. We report a case of aortic arch dissection in a patient with Turner syndrome who, from the ASI thresholds proposed, was deemed to be at low risk of aortic dis-section or rupture and was not eligible for prophylactic surgery. This case report strongly supports careful monitoring and surgical evaluation even when the ASI is gnificant risk factors are present.

关键词： Aortic dissection Aortic aneurysm Turner syndrome

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