Prognostic value of the preoperative study of cerebrospinal fluid dynamics in Chiari malformations: a pilot study.

PURPOSE: In patient with Chiari type I malformations (CM1), indication for surgery can be difficult to establish. Headaches are a common complaint. Factors that predict headache relief have not been clearly identified. Several studies have aimed to examine cerebrospinal fluid (CSF) hydrodynamics in patients with CM1 by using phase-contrast MRI (pcMRI), which is currently the only non-invasive method for assessing craniospinal hydrodynamics and hemodynamics. People with CM1 present alterations in cerebrospinal fluid (CSF) and cerebral blood dynamics. The objective of the present study was to identify hydrodynamic criteria that are predictive of positive clinical outcome (headache relief) after posterior fossa decompression surgery in patient with CM1. METHOD: 41 patients who underwent posterior fossa decompression surgery at Amiens-Picardie University Hospital (Amiens, France) between 2016 and 2021 were retrospectively included. We used preoperative pcMRI to analyze CSF dynamics. Stroke volumes of cerebrospinal fluid were quantified at the aqueduct of Sylvius (SVaqu), subarachnoid spaces near to C2-C3 (SVC2C3) vertebral junction, prepontine cisterns, foramen magnum, and brainstem. CSF pulsatility was analyzed in relation to whether patients reported postoperative headache relief. Statistical analyses were based on Student's t-test. RESULTS: 12 patients reported headache relief. The mean SVaqu was significantly higher in patients with headache relief than in those without relief (65 and 32.13µL/CC, p ≤ 0.05). The mean SVC2-C3 was significantly lower in patients with headache relief than in patients without relief (484.58 and 612.94µL/CC, p ≤ 0.05). The two groups of patients did not differ significantly in terms of the area of the narrowest part of the aqueduct of Sylvius or the Evans index. CONCLUSION: SVaqu may have prognostic value for headache relief following surgery for CM1. Further investigation is warranted. This association is likely related to the recruitment of intraventricular pulsatility, which may help regulate potential intracranial pressure changes. Notably, this pulsatility does not appear to be linked to morphological features.