Natali Arturo Nicola, Carniel Emanuele Luigi, Frigo Alessandro, Pavan Piero Giovanni, Todros Silvia, Pachera Paola, Fontanella Chiara Giulia, Rubini Alessandro, Cavicchioli Laura, Avital Yochai, De Benedictis Giulia Maria
Department of Industrial Engineering, University of Padova, Italy.
Centre for Mechanics of Biological Materials, University of Padova, Italy.
Exp Physiol. 2016 May 1;101(5):641-56. doi: 10.1113/EP085476. Epub 2016 Mar 24.
What is the central question of this study? Prostheses for treatment of urinary incontinence elicit complications associated with an inadequate mechanical action. This investigation aimed to define a procedure addressed to urethral mechanical characterization. Experimental tests are the basis for constitutive formulation, with a view to numerical modelling for investigation of the interaction between the tissues and a prosthesis. What is the main finding and its importance? Horse urethra, selected for its histomorphometric similarity to human urethra, was characterized by integrated histological analysis and mechanical tests on the biological tissue and structure, leading to constitutive formulation. A non-linear, anisotropic and time-dependent response was found, representing a valid basis for development of a numerical model to interpret the functional behaviour of the urethra. Urinary dysfunction can lead to incontinence, with an impact on the quality of life. Severe dysfunction can be overcome surgically by the use of an artificial urinary sphincter. Nonetheless, several complications may result from inappropriate functioning of the prosthesis, in many instances resulting from an unsuitable mechanical action of the device on the urethral tissues. Computational models allow investigation of the mechanical interaction between biological tissues and biomedical devices, representing a potential support for surgical practice and prosthesis design. The development of such computational tools requires experimental data on the mechanics of biological tissues and structures, which are rarely reported in the literature. The aim of this study was to provide a procedure for the mechanical characterization of urethral tissues and structures. The experimental protocol included the morphometric and histological analysis of urethral tissues, the mechanical characterization of the response of tissues to tensile and stress-relaxation tests and evaluation of the behaviour of urethral structures by inflation tests. Results from the preliminary experiments were processed, adopting specific model formulations, and also providing the definition of parameters that characterize the elastic and viscous behaviour of the tissues. Different experimental protocols, leading to a comprehensive set of experimental data, allow for a reciprocal assessment of reliability of the investigation approach.
本研究的核心问题是什么？用于治疗尿失禁的假体引发了与机械作用不足相关的并发症。本调查旨在确定一种针对尿道机械特性描述的程序。实验测试是本构公式的基础，以便进行数值模拟来研究组织与假体之间的相互作用。主要发现及其重要性是什么？马尿道因其组织形态计量学与人类尿道相似而被选中，通过对生物组织和结构进行综合组织学分析及力学测试对其进行特性描述，从而得出本构公式。发现了一种非线性、各向异性且随时间变化的响应，这为开发用于解释尿道功能行为的数值模型提供了有效的基础。排尿功能障碍可导致尿失禁，影响生活质量。严重的功能障碍可通过使用人工尿道括约肌进行手术治疗。然而，假体功能不当可能会导致多种并发症，在许多情况下是由于该装置对尿道组织的机械作用不合适所致。计算模型能够研究生物组织与生物医学装置之间的机械相互作用，为手术实践和假体设计提供潜在支持。此类计算工具的开发需要生物组织和结构力学方面的实验数据，而文献中对此报道甚少。本研究的目的是提供一种对尿道组织和结构进行机械特性描述的程序。实验方案包括对尿道组织进行形态计量学和组织学分析、对组织在拉伸和应力松弛测试中的响应进行机械特性描述以及通过膨胀测试评估尿道结构的行为。采用特定的模型公式对初步实验结果进行处理，并给出表征组织弹性和粘性行为的参数定义。不同的实验方案可得出一套全面的实验数据，从而能够对研究方法的可靠性进行相互评估。
