Numerical study of intrathecal drug delivery to a permeable spinal cord: effect of catheter position and angle.

Intrathecal delivery is a procedure involving the release of therapeutic agents into the cerebrospinal fluid (CSF) hrough a catheter. It holds promise for treating high-impact central nervous system pathologies, for which systemic administration routes are ineffective. In this study we introduce a numerical model able to simultaneously account for solute transport in the fluid and in the spinal cord. Using a Discontinuous Galerkin method and a three-dimensional patient-specific geometry, we studied the effect of catheter position and angle on local spinal cord drug concentration. We considered twenty cardiac cycles to limit the computational cost of our approach, which resolves the physics both in space and time. We used clinically representative data for the drug injection speed and dose rate, and scaled drug diffusion/penetration properties to obtain observable effects during the considered simulation time. Based on our limited set of working parameters, lateral injection perpendicular to the cord turned out to be more effective than other configurations. Even if the adopted scaling does not allow for a direct clinical translation (a wider parametric assessment of the importance of CSF flow, geometry and diffusion properties is needed), it did not weaken our numerical approach, which can be used to systematically investigate multiple catheter, geometry and fluid/tissue properties configurations, thus paving the way for therapy control.