Intracranial pressure is affected by head rotation: effect of dynamic jugular stenosis on lumbar puncture opening pressure.

Background: Studies suggest head positioning may impact cerebral venous outflow by creating dynamic stenosis in the internal jugular veins (IJVs) in susceptible individuals.

Objective: To examine the relationships between IJV pressure gradients and intracranial pressures, measured via lumbar puncture (LP), on head rotation in patients with cerebral venous outflow disorders (CVDs).

Methods: A retrospective chart review was conducted on consecutive adult patients suspected of having CVD who underwent diagnostic cerebral venous venography with rotational IJV venography and superior sagittal sinus (SSS) pressure measurements in multiple head positions followed immediately by LP in neutral and with rotation. Data on IJV pressures, SSS pressures, and LP opening pressure (OP) were collected and analyzed.

Results: In this sample of 70 patients, 9% developed moderate, 53% severe, and 30% occlusive rotational stenosis of the right IJV with 90 degree rightward rotation, resulting in mean jugular gradients of 5.5 mm Hg (SD 4.7). On head rotation, 59 (84%) patients experienced an increase in SSS pressures, and 67 (96%) experienced an increase in LP OP from neutral on head rotation (mean change 5.5 (SD 3.54) mm Hg). On average, for every 1 mm Hg increase in IJV trans-stenosis gradient, a 0.55 mm Hg increase in SSS pressure and a 0.27 cm H₂O increase in LP OP occurred.

Conclusion: In this sample of consecutive CVD patients, dynamic IJV stenosis pressure gradients predicted changes in SSS pressure and LP OP. As IJV pressure gradients increased, there was a near immediate increase in CSF pressure, roughly commensurate to the cervical gradients. These findings suggest that single position LP OP may only represent a snapshot of CSF pressure in a dynamic pressure system.