|Authors||V. Vinje, J. Brucker, M. E. Rognes, K. Mardal and V. Haughton|
|Title||Fluid dynamics in syringomyelia cavities: Effects of heart rate, CSF velocity, CSF velocity waveform and craniovertebral decompression|
|Project(s)||Waterscape: The Numerical Waterscape of the Brain, Department of Numerical Analysis and Scientific Computing|
|Publication Type||Journal Article|
|Year of Publication||2018|
|Journal||The Neuroradiology Journal|
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 CSF flow velocities in a model of syringomyelia.
Materials and Methods: With Phase Contrast MR we measured CSF and syrinx fluid velocities in a Chiari patient before and after craniovertebral decompression. With an idealized 2D 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/sec respectively in the SAS and the syrinx before surgery and at 2.7 and 1.5 cm/sec after surgery. In the model, syrinx velocity varied between 0.91 and 12.70 cm/sec. Increasing CSF inlet velocities from 1.56 to 4.69 cm/sec 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.