title: Poro-elastic modeling of Syringomyelia - a systematic study of the effects of pia mater, central canal, median fissure, white and gray matter on pressure wave propagation and fluid movement within the cervical spinal cord.
abstract: Syringomyelia, fluid-filled cavities within the spinal cord, occurs frequently in association with a Chiari I malformation and produces some of its most severe neurological symptoms. The exact mechanism causing syringomyelia remains unknown. Since syringomyelia occurs frequently in association with obstructed cerebrospinal fluid (CSF) flow, it has been hypothesized that syrinx formation is mechanically driven. In this study we model the spinal cord tissue either as a poro-elastic medium or as a solid linear elastic medium, and simulate the propagation of pressure waves through an anatomically plausible 3D geometry, with boundary conditions based on in vivo CSF pressure measurements. Then various anatomic and tissue properties are modified, resulting in a total of 11 variations of the model that are compared. The results show that an open segment of the central canal and a stiff pia (relative to the cord) both increase the radial pressure gradients and enhance interstitial fluid flow in the central canal. The anterior median fissure, anisotropic permeability of the white matter, and Poisson ratio play minor roles.
authors.affiliation: a Simula Research Laboratory , P.O. Box 134, 1325 Lysaker , Norway.|b Department of Informatics , University of Oslo , P.O. Box 1080 Blindern, 0316 Oslo , Norway.
authors.forename: Karen H
authors.initials: KH
authors.lastname: Støverud
authors.affiliation: a Simula Research Laboratory , P.O. Box 134, 1325 Lysaker , Norway.
authors.forename: Martin
authors.initials: M
authors.lastname: Alnæs
authors.affiliation: a Simula Research Laboratory , P.O. Box 134, 1325 Lysaker , Norway.|b Department of Informatics , University of Oslo , P.O. Box 1080 Blindern, 0316 Oslo , Norway.
authors.forename: Hans Petter
authors.initials: HP
authors.lastname: Langtangen
authors.affiliation: a Simula Research Laboratory , P.O. Box 134, 1325 Lysaker , Norway.|c Wisconsin Institutes of Medical Research , 1111 Highland Ave., Madison , WI 53705 , USA.
authors.forename: Victor
authors.initials: V
authors.lastname: Haughton
authors.affiliation: a Simula Research Laboratory , P.O. Box 134, 1325 Lysaker , Norway.|d Department of Mathematics , University of Oslo , P.O. Box 1080 Blindern, 0316 Oslo , Norway.
authors.forename: Kent-André
authors.initials: KA
authors.lastname: Mardal
mesh_terms: D000818:Animals; D001139:Arnold-Chiari Malformation / Q000150:complications / Q000473:pathology; D015170:Cerebrospinal Fluid Pressure; D066193:Cervical Cord / Q000502:physiology*; D002574:Cervical Vertebrae / Q000502:physiology; D004195:Disease Models, Animal; D045604:Extracellular Fluid / Q000502:physiology; D066128:Gray Matter / Q000502:physiology*; D021621:Imaging, Three-Dimensional; D008954:Models, Biological; D009068:Movement; D010841:Pia Mater / Q000502:physiology*; D012756:Sheep; D013595:Syringomyelia / Q000150:complications / Q000473:pathology*; D066127:White Matter / Q000502:physiology*
keywords: cerebrospinal fluid flow; poro-elasticity; spinal cord; syringomyelia; wave propagation