REGIONAL BLOOD-FLOW, PLASMA-VOLUME, AND VASCULAR-PERMEABILITY IN THE SPINAL-CORD, THE DURAL SAC, AND LUMBAR NERVE ROOTS

Objectives. This study quantified the regional blood flow (RBF), plasm a volume (PV), and the vascular permeability (VP) in the spinal cord, spinal nerve roots, and the dural sac. Summary of Background Data. Spi nal cord hemodynamics have been investigated. However, the full segmen tal distribution of blood flow to the spinal cord and nerve roots has not been worked out. Vascular permeability of the spinel cord and nerv e roots has been investigated but results regarding the spinal nerve r oots have not been consistent. Methods. Eight Labrador dogs were used. Regional blood flow was measured with microspheres. Plasma volume and vascular permeability were assessed by the distribution spaces Of rad ioactively labeled plasma proteins. Results. Regional blood flow was h ighest in the cervical and lumbar cord. Average (SEM) RBF values of th e cord and spinal nerve roots were 10.4 +/- 1.0 and 4.4 +/- 0.5 mL/min 100 g, respectively. Plasma volume of the spinal cord was 0.85 +/- 0. 06 mL/100 g and 1.29 +/- 0.17 mL/100 g in the spinal nerve roots. Vess els in the spinal nerve roots had significantly greater permeability t o albumin than those of the spinal cord (P < 0.001). Conclusions. The quantitative flow measurements showed the existence of three main anat omic territories in the cord. The vascular permeability of vessel in t he spinal nerve roots appears greater than that of the spinal cord, in dicating that spinal nerve roots are located outside the blood brain b arrier. Diffusion might be one of the nutritional pathways to spinal n erve roots.