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

Purpose In patient with Chiari type I malformations (CMI), indication for surgery can be difficult to establish. Headaches are a common complaint. Factors that predict headache relief have not been clearly identified. Various research has attempted to understand the hydrodynamic in patient with CMI by applying phase-contrast MRI (pcMRI) – only non-invasive technique for studying craniospinal hydrodynamics and hemodynamic. People with CMI 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 CMI. 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. CSF stoke volume were measured at the level of aqueduct of Sylvius (SV _aqu ), subarachnoid spaces near to C2-C3 (SV _C2C3 ) vertebral junction, prepontine cisterns, foramen magnum, and brainstem. CSF pulsatility was studied as a function of the postoperative headache relief reported (or not) by patients. Statistical analyses were based on Student's t-test. Results 12 patients reported headache relief. The mean SV _aqu was significantly higher in patients with headache relief than in those without relief (65 and 32.13µL/CC, p ≤ 0.05). The mean SV _C2−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 might have prognostic value for headache relief after CMI surgery. Further analysis is needed. This is probably related to recruitment of intraventricular pulsatility, which helping regulate potential intracranial pressure alteration. This pulsatility doesn't seem related to morphology.