2.21 Evaluation of the New Marburg Cerebrospinal Fluid Model with Human Spondylopathies

The Marburg model is based on the theorem that a few proteins (<200 mg/L) filtered from blood through the molecular sieve of blood-cerebrospinal fluid barrier (B-CSF-B) have blood proteins added to them in the lymph, traveling from paravertebral lymph vessels into the spinal CSF; thus proteins increase to <420 mg/L. Normally, CSF flows out from spinal canal into paraspinal lymph vessels. The upright human position reverses the equilibrium between CSF and lymph pressures, allowing minimal lymph leakage into the lumbar CSF: 0.3 mL of lymph elevates CSF proteins from 200 to 400 mg/L. Prolapses alter CSF backbone clearance via a valve mechanism, the disc prolapse bulges into the spinal cord and increases the resistance of CSF outflow. Lymph admittance is facilitated, however, thus more lymph enters and total amount of protein increases in the lumbar CSF. Molar IgG/albumin ratios show the entrance of plasma proteins in cases of lumbar prolapses. The IgG/albumin ratio increases from 0.049 nmol/nmol with controls up to 0.065 nmol/nmol in individuals with mass prolapses in lumbar CSF; thus approximating an IgG/albumin ratio of 0.125 in normal human plasma.