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. 2008 Dec 5;80(4):392–399. doi: 10.1136/jnnp.2008.157164

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© Zamboni et al 2009

This is an open-access article distributed under the terms of the Creative Commons Attribution Non-commercial License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Patterns of chronic cerebrospinal venous insufficiency observed in multiple sclerosis (MS) cases. Normal: example of normal extracranial venous outflow direction. In particular, the black arrows depict the drainage of the internal jugular vein (IJV) system into the superior vena cava (SVC), and of the vertebral plexus (Vplex) outward from the spinal cord into the azygous system (AZY). Type A (30%): this pattern is characterised by a steno-obstruction of the proximal azygous, associated with a closed stenosis of one of the two IJVs (red crosses). Reflux is always present, under all postural conditions, in the stenosed IJV (red arrow), with a compensatory controlateral IJV that appears with an ample cross-sectional area of the IJV. Reflux in the deep cerebral veins (DCVs) was detected by means of transcranial colour-coded Doppler sonography in 60% of cases. In the azygous vein the reflux has an effect as far as the lumbar veins, being able to re-enter the caval circle either through the system of the hemiazygous vein–left renal vein, or by rising again inside the rachis. Type B (38%): this pattern is characterised by significant stenoses of both IJVs and the proximal azygous (red crosses). Reflux is present in all three venous segments (red arrows). Cerebral venous outflow for overcoming the IJVs stenosis re-enters the heart mainly through cervical collateral circles (fig 1B); for the hampered azygous vein outflow, the collateral circles include again the intrarachidian pathway, or the system of the renal-hemiazygous. Type C (14%): this pattern is characterised by bilateral stenosis in both IJVs, with a normal azygous system (red crosses). Reflux (red arrows) occurs in the IJVs but not in the vertebral veins, with cervical or intracranial collateral circles that shunt blood towards the superior vena cava or the azygous vein system, respectively. The resulting overload of the azygous system is depicted by black bold arrows. Type D (18%): in this pattern the azygous system was constantly affected in various segments (red crosses), resulting in a forced venous drainage towards the intrarachidian circles in an upward direction (red arrows). The vertebral veins appeared to be refluent, and the intracranial collateral circles seek to gain the IJVs, as confirmed by reflux detection in DCVs in 90% of cases. At times, the IJVs were also affected (six cases, 50%), causing an additional obstruction in these patients. IVC, inferior vena cava; L-REN, left renal vein.