Finite Element Modeling of Factors Influencing Optic Nerve Head Deformation Due to Intracranial Pressure
Finite Element Modeling of Factors Influencing Optic Nerve Head Deformation Due to Intracranial Pressure
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DOI：
10.1167/iovs.15-17573
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发表时间：
2016-04-01
影响因子：
4.4
通讯作者：
Ethier, C. Ross
中科院分区：
文献类型：
--
作者：
Feola, Andrew J.;Myers, Jerry G.;Ethier, C. Ross
目的.视觉障碍和颅内压（VIIP）综合征是长期航天飞行的一个健康问题，一个拟议的风险因素是颅内压（ICP）升高。我们的目标是使用有限元模型来模拟颅内压升高和个体间差异如何影响视神经乳头（ONH）内的组织变形。我们考虑了三种ICP条件：地球上的直立和仰卧位置以及假设在慢性微重力下发生的ICP升高。在每种情况下，我们使用拉丁超立方体采样考虑一系列的压力和ONH组织的机械性能，确定每个输入对以下结果的影响措施：在前板组织，筛板，和后板视神经的峰值应变。升高的菌株可以改变细胞表型并诱导组织重塑。颅内压升高增加了椎板后视神经的张力。IOP、ICP、视神经和筛板硬度的变化对ONH内的应变影响最大。我们预测，在微重力环境中，5%到47%的人会经历比地球上预期的更大的椎板后视神经峰值应变。软视神经或软脑膜和颅内压升高被确定为这些“极端”应变的危险因素。ONH的颅内压和机械特性影响椎板后视神经极端应变的风险。这些极端的应变可能会激活机械敏感细胞，诱导组织重塑，是VIIP发展的风险因素。未来的研究还必须考虑ONH解剖结构的变化。
PURPOSE. Visual impairment and intracranial pressure (VIIP) syndrome is a health concern for long-duration spaceflight, and a proposed risk factor is elevation of intracranial pressure (ICP). Our goal was to use finite element modeling to simulate how elevated ICP and interindividual differences affect tissue deformation within the optic nerve head (ONH).METHODS. We considered three ICP conditions: the upright and supine position on earth and an elevated ICP assumed to occur in chronic microgravity. Within each condition we used Latin hypercube sampling to consider a range of pressures and ONH tissue mechanical properties, determining the influence of each input on the following outcome measures: peak strains in the prelaminar tissue, lamina cribrosa, and retrolaminar optic nerve. Elevated strains can alter cell phenotype and induce tissue remodeling.RESULTS. Elevating ICP increased the strains in the retrolaminar optic nerve. Variations in IOP, ICP, and in optic nerve and lamina cribrosa stiffness had the strongest influence on strains within the ONH. We predicted that 5% to 47% of individuals in microgravity would experience peak strains in the retrolaminar optic nerve larger than expected on earth. Having a soft optic nerve or pia mater and elevated ICP were identified as risk factors for these "extreme'' strains.CONCLUSIONS. Intracranial pressure and mechanical properties of the ONH influence the risk for experiencing extreme strains in the retrolaminar optic nerve. These extreme strains may activate mechanosensitive cells that induce tissue remodeling and are a risk factor for the development of VIIP. Future studies must also consider variations in ONH anatomy.