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dc.contributor.authorKwon, Joanneen
dc.contributor.authorShipley, Rebecca Jen
dc.contributor.authorEdirisinghe, Mohanen
dc.contributor.authorRayment, Andrew Wen
dc.contributor.authorBest, Serenaen
dc.contributor.authorCameron, Ruthen
dc.contributor.authorSalam, Tahrinaen
dc.contributor.authorRose, Geoffrey Een
dc.contributor.authorEzra, Daniel Gen
dc.date.accessioned2015-02-05T15:15:17Z
dc.date.available2015-02-05T15:15:17Z
dc.date.issued2014-11-12en
dc.identifier.citationJournal of the Mechanical Behavior of Biomedical Materials Volume 42, February 2015, Pages 116–128. DOI: 10.1016/j.jmbbm.2014.11.004en
dc.identifier.issn1751-6161
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/246701
dc.description.abstractPtosis describes a low position of the upper eyelid. When this condition is due to poor function of the levator palpebrae superioris muscle, responsible for raising the lid, “brow-suspension” ptosis correction is usually performed, which involves internally attaching the malpositioned eyelid to the forehead musculature using brow-suspension materials. In service, such materials are exposed to both rapid tensile loading and unloading sequences during blinking, and a more sustained tensile strain during extended periods of closure. In this study, various mechanical tests were conducted to characterise and compare some of commonly-used synthetic brow-suspension materials (Prolene®, Supramid Extra® II, Silicone rods (Visitec® Seiff frontalis suspension set) and Mersilene® mesh) for their time-dependent response. At a given constant tensile strain or load, all of the brow-suspension materials exhibited stress-relaxation or creep, with Prolene® having a statistically different relaxation or creep ratio as compared with the others. Uniaxial tensile cyclic tests through preconditioning and fatigue tests demonstrated drastically different time-dependent response amongst the various materials. Although the tests generated hysteresis force-strain loops for all materials, the mechanical properties such as the number of cycles required to reach the steady-state, the reduction in the peak force, and the cyclic energy dissipation varied considerably. To reach the steady-state, Prolene® and the silicone rod required the greatest and the least number of cycles, respectively. Furthermore, the fatigue tests at physiologically relevant conditions (15% strain controlled at 6.5Hz) demonstrated that the reduction in the peak force during 100000 cycles ranged from 15 to 58%, with Prolene® and the silicone rod exhibiting the greatest and the least value, respectively. Many factors need to be considered to select the most suitable brow-suspension material for ptosis correction. These novel data on the mechanical time-dependent performance could, therefore help to guide clinicians in their decision-making process for optimal surgical outcome.
dc.description.sponsorshipThis study was supported by a knowledge exchange and enterprise funding (“Discovery to use”) to the authors at University College London (UCL). Authors Ezra and Rose acknowledge funding by the Department of Health through the National Institute for Health Research to Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology Biomedical Research Centre. All the mechanical testing was performed at Cambridge University and we are very grateful for the facilities provided.
dc.languageEnglishen
dc.language.isoenen
dc.publisherElsevier
dc.titleStress-relaxation and fatigue behaviour of synthetic brow-suspension materialsen
dc.typeArticle
dc.description.versionThis is the accepted manuscript. The final version is available from Elsevier at http://www.sciencedirect.com/science/article/pii/S1751616114003452#.en
prism.endingPage128
prism.publicationDate2014en
prism.publicationNameJournal of the Mechanical Behavior of Biomedical Materialsen
prism.startingPage116
prism.volume42en
dc.rioxxterms.funderNIHR
dcterms.dateAccepted2014-11-03en
rioxxterms.versionofrecord10.1016/j.jmbbm.2014.11.004en
rioxxterms.licenseref.urihttp://www.rioxx.net/licenses/all-rights-reserveden
rioxxterms.licenseref.startdate2014-11-12en
dc.contributor.orcidBest, Serena [0000-0001-7866-8607]
dc.contributor.orcidCameron, Ruth [0000-0003-1573-4923]
dc.identifier.eissn1878-0180
rioxxterms.typeJournal Article/Reviewen
rioxxterms.freetoread.startdate2015-11-12


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