Volumetric response after closure of a spinal CSF leak in patients with spontaneous intracranial hypotension: a multicompartmental longitudinal study.

Background Cerebrospinal fluid (CSF) loss in spontaneous intracranial hypotension (SIH) is accompanied by volume shifts between the intracranial compartments. This study investigated tricompartimental and longitudinal volume shifts after closure of a CSF leak. Methods Patients with SIH and suitable pre-therapeutic and post-therapeutic imaging for volumetric analysis were identified from our tertiary care center between 2020 and 2023. The Bern SIH score was calculated. Pre-interventional and post-interventional volumetry encompassed the CSF, parenchymal and venous compartments (ie, venous sinus and choroid plexus volumes). Results In total, 32 patients with SIH (49.7±16.0 years, 22 women) met inclusion criteria. The mean SIH score decreased between baseline (4.5±2.7) and early (2.7±2.3, <7 days after intervention), and also late follow-up (1.4±1.7, follow-up ≥7 days) after leak closure. This was accompanied by a significant increase in ventricular volume from 22.1 to 25.0 mL (P=0.01) at early follow-up, and 23.9 mL at later follow-up (P=0.080). In contrast, venous sinus volumes decreased from 13.8 to 9.6 mL (P=0.016) at early follow-up, and 10.0 mL (P=0.007) at late follow-up. No significant change in mean choroid plexus, total gray or total white matter volume was observed. Conclusions Closure of a spinal CSF leak leads to an early increase in ventricular CSF volume and a decrease in venous sinus volume. The results reflect the long-term convergence of the SIH score to normal values and indicate that permanent closure of a CSF leak induces a stable recompensation of the intracranial compartments without involving significant volume shifts within the cerebral parenchyma.