Computational Investigation of Cerebrospinal Fluid Dynamics in the Posterior Cranial Fossa and Cervical Subarachnoid Space in Patients with Chiari I Malformation

Abstract

PurposePrevious computational fluid dynamics (CFD) studies have demonstrated that the Chiari malformation is associated with abnormal cerebrospinal fluid (CSF) flow in the cervical part of the subarachnoid space (SAS), but the flow in the SAS of the posterior cranial fossa has received little attention. This study extends previous modelling efforts by including the cerebellomedullary cistern, pontine cistern, and 4th ventricle in addition to the cervical subarachnoid space.MethodsThe study included one healthy control, Con1, and two patients with Chiari I malformation, P1 and P2. Meshes were constructed by segmenting images obtained from T2-weighted turbo spin-echo sequences. CFD simulations were performed with a previously verified and validated code. Patient-specific flow conditions in the aqueduct and the cervical SAS were used. Two patients with the Chiari malformation and one control were modelled.ResultsThe results demonstrated increased maximal flow velocities in the Chiari patients, ranging from factor 5 in P1 to 14.8 in P2, when compared to Con1 at the level of Foramen Magnum (FM). Maximal velocities in the cervical SAS varied by a factor 2.3, while the maximal flow in the aqueduct varied by a factor 3.5. The pressure drop from the pontine cistern to the cervical SAS was similar in Con1 and P1, but a factor two higher in P2. The pressure drop between the aqueduct and the cervical SAS varied by a factor 9.4 where P1 was the one with the lowest pressure jump and P2 and Con1 differed only by a factor 1.6.ConclusionThis pilot study demonstrates that including the posterior cranial fossa is feasible and suggests that previously found flow differences between Chiari I patients and healthy individuals in the cervical SAS may be present also in the SAS of the posterior cranial fossa.

Hydraulic resistance of periarterial spaces in the brain

“…Development of a fully-resolved fluid-dynamic model that captures CSF transport through the entire brain is beyond current capabilities for two reasons: (i) the very large computational cost of such a simulation, and (ii) the lack of detailed knowledge of the configuration and mechanical properties of the various flow channels throughout the glymphatic pathway, especially deep within the brain. We note that these limitations and the modest number of publications modeling CSF transport through the brain are in contrast with the much more extensive body of research modeling CSF flow in the spinal canal, which has pursued modeling based on idealized [21–23], patient-specific [24, 25], and in vitro [26] geometries (see the recent review articles [27–29]).…”

Hydraulic resistance of perivascular spaces in the brain

“…Development of a fully-resolved fluid-dynamic model that captures CSF transport through the entire brain is beyond current capabilities for two reasons: (i) the very large computational cost of such a simulation, and (ii) the lack of detailed knowledge of the configuration and mechanical properties of the various flow channels throughout the glymphatic pathway, especially deep within the brain. We note that these limitations and the modest number of publications modeling CSF transport through the brain are in contrast with the much more extensive body of research modeling CSF flow in the spinal canal, which has pursued modeling based on idealized [17, 18, 19], patient-specific [20, 21], and in vitro [22] geometries (see the recent review articles [23, 24, 25]).…”

Selected Problems of the Patient after the Peak-occipital Decompression Surgery Treatment in the Course of the Chiari type I Malformation

“…The Arnold-Chiari Syndrome (called Arnold-Chiari Malformation -ACM, Chiari Malformation -CM) is the malformation of the hindbrain and skull. It refers to moving downwards the tonsils of the cerebellum through a large opening to the upper part of the spinal canal [1,2]. There are no unequivocal explanations for the etiology of this primary disorder during development, hence congenital malformation.…”

“…In the case of Chiari type I Malformation, the tonsils of the cerebellum are located at least 3-5 mm below the level of the foramen magnum (FM) [1]. Due to impaired CSF flow, approximately 70-80% of CM I cases spinal cord syringomyelia develops.…”

“…Due to impaired CSF flow, approximately 70-80% of CM I cases spinal cord syringomyelia develops. In addition, hydrocephalus, scoliosis, kyphosis might occur [1,3,5]. CM I manifests various neurological symptoms that may be visible in the second or third decade of life or even when collecting information from older people it turns out that they have been present since birth or childhood and have intensified [6].…”