Cerebrospinal fluid dynamics along the optic nerve in patients with spontaneous cerebrospinal fluid rhinorrhea: a retrospective computed tomographic cisternography study.

Purpose: Spontaneous cerebrospinal fluid (CSF) rhinorrhea is related to intracranial pressure (ICP) and dynamic changes. This study investigated CSF dynamics along the optic nerve (ON) in patients with spontaneous CSF rhinorrhea.

Methods: The computed tomographic (CT) cisternographies of 66 patients (132 eyes) with spontaneous CSF rhinorrhea were analysed. The contrast-loaded CSF (CLCSF) density was measured in Hounsfield units (HU) at three regions of interest (ROIs) along the ON and adjusted by the basal cistern density. The CLCSF density and ON sheath diameter (ONSD) were analysed between both sides in the different ICP groups.

Results: When comparing the density of CLCSF along the ON, no significant differences were found between the ipsilateral and contralateral sides of the leakage. The distribution of CLCSF along the ON showed a highly significant density reduction from the canalicular segment to the bulbar segment on both sides. The CLCSF density significantly decreased on the ipsilateral ON in the canalicular segment and tended to decrease on the ipsilateral ON in the bulbar and canal segments compared with that on the contralateral ON in the low-ICP group. The ONSD tended to decrease on the ipsilateral side of leakage.

Conclusions: According to the CLCSF density on CT cisternography, CSF dynamics along the ON may bilaterally decrease from the optic canal to the retrobulbar segment. Cerebrospinal fluid (CSF) dynamics are possibly influenced by differences in ICP, and a lower ICP may cause more obvious differences or impairments in CSF dynamics along the ipsilateral ON.