三维腹股沟疝修复补片的制备与性能研究

为减少腹股沟疝补片植入后的相关并发症,该文根据耻骨肌孔临床尺寸数据,设计和成型三维结构疝修复补片,并对试样的力学性能进行分析。利用正交试验设计,分析试样的组织结构,拉伸﹑撕裂﹑顶破等性能随模压成型条件的变化规律,优选出最佳的成型参数。研究结果表明:三维腹股沟疝修复补片的最优成型工艺参数为:温度140℃﹑时间45min﹑压强0. 25 MPa。此条件下,制备的三维补片的拉伸断裂性能﹑撕裂性能及顶破性能优异。同时得到结论,温度是影响疝修补片力学性能的最主要因素,而张力是影响疝修补片面密度和孔隙率的最主要因素。

Limitations of multimodality imaging in the diagnosis of pannus formation in prosthetic aortic valve and review of the literature

Pannus formation is a rare complication and occurs almost exclusively in mechanical prosthetic valves.It consists of fibrous tissue that covers the surface of the prosthesis either concentrically or eccentrically,resulting in valve dysfunction.The pathophysiology seems to be associated to a chronic inflammatory process that explains the late and insidious clinical presentation.This diagnosis should be considered in patients with high transvalvular gradients on transthoracic echo,and workup should be completed with fluoroscopy and transesophageal echocardiography.Treatment is always surgical and recurrence is rare.We present a case of pannus formation in a prosthetic aortic valve and a review of the literature regarding this disorder.

Simulation of blood flow in a small-diameter vascular graft model with a swirl (spiral) flow guider

Small-diameter vascular grafts are in large demand for coronary and peripheral bypass procedures, but present products still fail in long-term clinical application. In the present communication, a new type of small-diameter graft with a swirl flow guider was proposed to improve graft patency rate. Flow pattern in the graft was simulated numerically and compared with that in a conventional graft. The numerical results revealed that the swirl flow guider could indeed make the blood flow rotate in the new graft. The swirling flow distal to the flow guider significantly altered the flow pattern in the new graft and the ve- locity profiles were re-distributed. Due to the swirling flow, the blood velocity near the vessel wall and wall shear rate were greatly enhanced. We believe that the increased blood velocity near the wall and the wall shear rate can impede the occurrence of acute thrombus formation and intimal hyperplasia, hence can improve the graft patency rate for long-term clinical use.

人工血管与药物

人工血管的成功取决于多种因素,包括材料的化学、物理性质和结构设计。本文通过回顾人工血管的历史发展和作者的一些工作,在一定程度上总结过去的经验,希望对人工血管的进一步发展能够有所帮助。

Customized and in situ fenestrated stent-grafts:A reinforced poly-ε-caprolactone branch cuff designed to prevent type III endoleaks and enhance hemodynamics

Superior long-term anchorage of the bridging stent-grafts from the fenestrated main body endograft could be achieved with the addition of a flared cuff,capable of preventing the previously observed fabric fraying around the fenestration as a result of the balloon angioplasty of the seal zone.This novel stent cuff design will also facilitate more complete biointegration of the devices,eliminate the hemodynamic variation as well as significantly reduce the possibility of a Type III endoleak.The feasibility of this concept is demonstrated by observations made from in-situ tests performed in a Beta endograft design.Flared cuffs made of poly(ε-caprolactone)supported with a weft-knitted polyester structure can be manufactured with various configurations to optimize the transition from the main body of the endograft,thus preventing the currently marketed designs’hemodynamic perturbation while also promoting endograft biointegration.This concept represents an evolution in branch graft design,which may enhance the long-term durability of customized fenestrations and open new applications for in-vivo graft fenestration in the near future.Further ongoing investigation to optimize its structure,X-ray opacity,fixation to the flared stent,and material biocompatibility are still required to build upon this concept’s proof.

Donkey pericardium as a select sourcing to manufacture percutaneous heart valves:Decellularization has not yet demonstrated any clear cut advantage to glutaraldehyde treatment

Background:The donkey pericardium is considered a good candidate to manufacture percutaneous heart valves based upon its thinness,low cellularity and undulating collagen bundles and laminates.Decellularization represents an avenue worth exploring,should its superiority to glutaraldehyde-treated pericardium be demonstrated.Materials and methods:Donkey pericardium was divided into two groups:regular glutaraldehyde fixation and mild decellularization.The treated pericardia were observed using scanning electron microscopy,histology and transmission electron microscopy.Tensile tests were performed along the axial and perpendicular directions,with the data fitted into both the Gasser–Ogden–Holzapfel(GOH)material model and the Fung’s anisotropic one.Results:The microstructures of the pericardia processed by the two protocols were similar,showing collagen bundles and laminates free of flaws.The decellularization eliminated most of the cells,however leaving the structure somehow compressed.The collagen filaments in bundles were slightly blurry.The anisotropy rates of the non-decellularized specimens were almost identical to the decellularized ones.The decellularized pericardium appeared stiffer.Conclusion:The decellularization proved to be effective.However,it makes the tissue stiffer,which may lead to higher shear concentration during cardiac cycles and reduce its wavy microstructure.Therefore,it appears premature to select decellularized donkey pericardium to manufacture heart valves.

Towards Mutuality in the Canada-China Relationship:The Experience of the Department of Surgery at Laval University since the 1980s

The Department of Surgery at Laval University has been a key player in the development of Canada-China cooperation since the 1980s.The projects initiated and developed by Jean Couture and Guojin Liu to address cancer issues,and specifically breast cancer,were heralded as outstanding successes.In the meantime,the Department of Surgery at Laval University trained numerous Chinese scholars,students,and post-doctoral fellows who became leaders in their fields of expertise.A few of these scholars and students settled in Canada,but the vast majority returned home.Since 2007,a highly specialized research program related to surgical implants with the College of Textiles at Donghua University has been opening new avenues in medical textiles to develop expertise through student training,to launch bridges between textile engineers and clinicians,and to provide the industry with a unique expertise.The final goal is to improve the accessibility and affordability of health care delivery in both Canada and China.China is now a key player in related research and no longer requires foreign assistance.Since it can easily find multiple partners,Canada must be alert to building on its legacy and maintaining its privileged position.China is now a place for Canadian champions.