Fluid dynamics in syringomyelia cavities: Effects of heart rate,CSF velocity,CSF velocity waveform and craniovertebral decompression

Abstract

Purpose

How fluid moves during the cardiac cycle within a syrinx may affect its development. We measured syrinx fluid velocities before and after craniovertebral decompression in a patient and simulated syrinx fluid velocities for different heart rates, syrinx sizes and cerebrospinal fluid (CSF) flow velocities in a model of syringomyelia.

Materials and methods

With phase-contrast magnetic resonance we measured CSF and syrinx fluid velocities in a Chiari patient before and after craniovertebral decompression. With an idealized two-dimensional model of the subarachnoid space (SAS), cord and syrinx, we simulated fluid movement in the SAS and syrinx with the Navier-Stokes equations for different heart rates, inlet velocities and syrinx diameters.

Results

In the patient, fluid oscillated in the syrinx at 200 to 210 cycles per minute before and after craniovertebral decompression. Velocities peaked at 3.6 and 2.0 cm per second respectively in the SAS and the syrinx before surgery and at 2.7 and 1.5 cm per second after surgery. In the model, syrinx velocity varied between 0.91 and 12.70 cm per second. Increasing CSF inlet velocities from 1.56 to 4.69 cm per second increased peak syrinx fluid velocities in the syrinx by 151% to 299% for the three cycle rates. Increasing cycle rates from 60 to 120 cpm increased peak syrinx velocities by 160% to 312% for the three inlet velocities. Peak velocities changed inconsistently with syrinx size.

Conclusions

CSF velocity, heart rate and syrinx diameter affect syrinx fluid velocities, but not the frequency of syrinx fluid oscillation. Craniovertebral decompression decreases both CSF and syrinx fluid velocities.

Keywords

Cerebrospinal fluid Chiari I computational fluid dynamics syringomyelia

Get full access to this article

View all access options for this article.

References

Honey

Martin

Heran

MKS

. Syringomyelia fluid dynamics and cord motion revealed by serendipitous null point artifacts during Cine MRI. AJNR Am J Neuroradiol 2017; 38: 1845–1847.

Pinna

Alessandrini

Alfieri

et al.

Cerebrospinal fluid flow dynamics study in Chiari I malformation: Implications for syrinx formation. Neurosurg Focus 2000; 8: 1–8.

Lichtor

Egofske

Alperin

. Noncommunicating cysts and cerebrospinal fluid flow dynamics in a patient with a Chiari I malformation and syringomyelia—Part II. Spine 2005; 30: 1466–1472.

Martin

Labuda

Royston

et al.

Spinal subarachnoid space pressure measurements in an in vitro spinal stenosis model: Implications on syringomyelia theories. J Biomech Eng 2010; 132: 111007.

Bertram

. A numerical investigation of waves propagating in the spinal cord and subarachnoid space in the presence of a syrinx. J Fluids Struct 2009; 25: 1189–1205.

Ozawa

Matsumoto

Ohashi

et al.

Mechanical properties and function of the spinal pia mater. J Neurosurg Spine 2004; 1: 122–127.

Smith

Humphrey

. Interstitial transport and transvascular fluid exchange during infusion into brain and tumor tissue. Microvasc Res 2007; 73: 58–73.

Logg A, Mardal KA and Wells GN (eds) Automated solution of differential equations by the finite element method: The FEniCS book. Heidelberg: Springer Science & Business Media, 2012.

Vinje V. Simulating cerebrospinal fluid flow and spinal cord movement associated with syringomyelia—fluid-structure interaction in idealized geometries. MSc Thesis, University of Oslo, Norway, 2016.

10.

Brugières

Idy-Peretti

Iffenecker

et al.

CSF flow measurement in syringomyelia. AJNR Am J Neuroradiol 2000; 21: 1785–1792.

11.

Shah

Haughton

del Río

. CSF flow through the upper cervical spinal canal in Chiari I malformation. AJNR Am J Neuroradiol 2011; 32: 1149–1153.

12.

Linge

Mardal

Haughton

et al.

Simulating CSF flow dynamics in the normal and the Chiari I subarachnoid space during rest and exertion. AJNR Am J Neuroradiol 2013; 34: 41–45.

13.

Ogoh

Ainslie

. Cerebral blood flow during exercise: Mechanisms of regulation. J Appl Physiol (1985) 2009; 107: 1370–1380.