Convection-Enhanced Arborizing Catheter System Improves Local/Regional Delivery of Infusates Versus a Single-Port Catheter in Ex Vivo Porcine Brain Tissue

Standard treatment for glioblastoma is noncurative and only partially effective. Convection-enhanced delivery (CED) was developed as an alternative approach for effective loco-regional delivery of drugs via a small catheter inserted into the diseased brain. However, previous CED clinical trials revealed the need for improved catheters for controlled and satisfactory distribution of therapeutics. In this study, the arborizing catheter, consisting of six infusion ports, was compared to a reflux-preventing single-port catheter. Infusions of iohexol at a flow rate of 1 μL/min/microneedle were performed, using the arborizing catheter on one hemisphere and a single-port catheter on the contralateral hemisphere of excised pig brains. The volume dispersed (Vd) of the contrast agent was quantified for each catheter. Vd for the arborizing catheter was significantly higher than for the single-port catheter, 2235.8 ± 569.7 mm3 and 382.2 ± 243.0 mm3, respectively (n = 7). Minimal reflux was observed; however, high Vd values were achieved with the arborizing catheter. With simultaneous infusion using multiple ports of the arborizing catheter, high Vd was achieved at a low infusion rate. Thus, the arborizing catheter promises a highly desirable large volume of distribution of drugs delivered to the brain for the purpose of treating brain tumors.

BIOMECHANICS OF PORCINE BRAIN TISSUE UNDER FINITE COMPRESSION

While the developments in finite element method have made it possible to simulate the complex problems in biomechanics, building an accurate constitutive model of living tissues is a major factor in getting reliable finite element analysis (FEA) results. In this study, a set of experiments were performed to test the properties of porcine brain tissue under unconfined uniaxial compression with 20[Formula: see text]s hold time at varied strain levels (10–50%) and strain rates (0.1–1[Formula: see text]s[Formula: see text]). A novel method was developed to build a quasi-linear viscoelasticity (QLV) model. The elastic function and the relaxation function were calculated separately. An Odgen model was adopted to characterize the elastic behavior, while the relaxation response was modeled at six decay rates. A standard to choose the visco parameters was discussed and carried out. The disparity of parameter values in previous models was discussed and explained. It is suggested that this model should be used in the tested loading conditions (relaxation time, strain rate, strain levels).