Biomechanical and histological characteristics of passive esophagus: Experimental investigation and comparative constitutive modeling

Stavropoulou, EA; Dafalias, YF; Sokolis, DP

dc.contributor.author	Stavropoulou, EA	en
dc.contributor.author	Dafalias, YF	en
dc.contributor.author	Sokolis, DP	en
dc.date.accessioned	2014-03-01T01:29:55Z
dc.date.available	2014-03-01T01:29:55Z
dc.date.issued	2009	en
dc.identifier.issn	0021-9290	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/19409
dc.subject	Anisotropy	en
dc.subject	Histology	en
dc.subject	Inflation/extension	en
dc.subject	Mucosa-submucosa	en
dc.subject	Muscle	en
dc.subject	Strain-energy function	en
dc.subject.classification	Biophysics	en
dc.subject.classification	Engineering, Biomedical	en
dc.subject.other	Biomechanical analysis	en
dc.subject.other	Biomechanical properties	en
dc.subject.other	Biphasic	en
dc.subject.other	Collagen content	en
dc.subject.other	Constitutive modeling	en
dc.subject.other	Device application	en
dc.subject.other	Esophageal tissues	en
dc.subject.other	Experimental investigations	en
dc.subject.other	Exponential form	en
dc.subject.other	Force data	en
dc.subject.other	Geometrical analysis	en
dc.subject.other	Histological observations	en
dc.subject.other	Inflation/extension	en
dc.subject.other	Longitudinal stretch	en
dc.subject.other	Material parameter	en
dc.subject.other	Muscle layers	en
dc.subject.other	Muscle strain	en
dc.subject.other	Optimal design	en
dc.subject.other	Parameterized	en
dc.subject.other	Pseudoelastic response	en
dc.subject.other	Soft tissue	en
dc.subject.other	Strain energy functions	en
dc.subject.other	Zero-stress state	en
dc.subject.other	Anisotropy	en
dc.subject.other	Biological radiation effects	en
dc.subject.other	Biomechanics	en
dc.subject.other	Collagen	en
dc.subject.other	Glycoproteins	en
dc.subject.other	Histology	en
dc.subject.other	Medical problems	en
dc.subject.other	Strain energy	en
dc.subject.other	Muscle	en
dc.subject.other	collagen	en
dc.subject.other	elastin	en
dc.subject.other	animal tissue	en
dc.subject.other	article	en
dc.subject.other	biomechanics	en
dc.subject.other	elasticity	en
dc.subject.other	esophagus function	en
dc.subject.other	esophagus mucosa	en
dc.subject.other	histology	en
dc.subject.other	male	en
dc.subject.other	mathematical analysis	en
dc.subject.other	mathematical model	en
dc.subject.other	muscle contraction	en
dc.subject.other	nonhuman	en
dc.subject.other	passive movement	en
dc.subject.other	priority journal	en
dc.subject.other	rabbit	en
dc.subject.other	rigidity	en
dc.subject.other	Animals	en
dc.subject.other	Anisotropy	en
dc.subject.other	Computer Simulation	en
dc.subject.other	Elastic Modulus	en
dc.subject.other	Esophagus	en
dc.subject.other	Male	en
dc.subject.other	Models, Biological	en
dc.subject.other	Rabbits	en
dc.subject.other	Stress, Mechanical	en
dc.subject.other	Tensile Strength	en
dc.title	Biomechanical and histological characteristics of passive esophagus: Experimental investigation and comparative constitutive modeling	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/j.jbiomech.2009.08.018	en
heal.identifier.secondary	http://dx.doi.org/10.1016/j.jbiomech.2009.08.018	en
heal.language	English	en
heal.publicationDate	2009	en
heal.abstract	Information on the passive biomechanical properties of two-layered esophagus is still limited, although this would enhance our understanding of its physiology/pathophysiology and help to address problems in surgery, medical-device applications, and for the optimal design of prostheses. In this study, rabbit esophagi were excised and dissected into mucosa-submucosa and muscle layers that were submitted to histological quantification of elastin and collagen content and orientation, as well as to inflation-extension testing and geometrical analysis, i.e. delineation of the zero-stress state serving as a reference configuration for biomechanical analysis. The pressure-radius data of both layers displayed a monotonically rising slope with inflating pressure, unlike the sigma shape characterizing elastin-rich tissues, for which biphasic constitutive models were initially postulated. Three phenomenological expressions of strain-energy function (SEF), commonly appearing in soft-tissue biomechanics literature, were used in an attempt to model the pseudoelastic response of esophageal tissue, namely the exponential Fung-type SEF, and the combined neo-Hookean (isotropic) or quadratic (anisotropic) and exponential Fung-type SEF. Accurate fits were attained for the pressure-radius-force data, spanning a wide range of longitudinal stretch ratios, when using the exponential form: the biphasic SEFs failed to generate improved fits, being also over-parameterized. According to the calculated material parameters, mucosa-submucosa was stiffer than muscle in both directions, justified by our histological observation of increased collagen content in that layer, and tissue was stiffer longitudinally, substantiated by the increased elastin and collagen contents and their preferential alignment towards that direction. Our results demonstrate that the passive response of esophagus is best modeled with an exponential Fung-type SEF. (C) 2009 Elsevier Ltd. All rights reserved.	en
heal.publisher	ELSEVIER SCI LTD	en
heal.journalName	Journal of Biomechanics	en
dc.identifier.doi	10.1016/j.jbiomech.2009.08.018	en
dc.identifier.isi	ISI:000273135200005	en
dc.identifier.volume	42	en
dc.identifier.issue	16	en
dc.identifier.spage	2654	en
dc.identifier.epage	2663	en