Obstructive hydrocephalus due to vertebrobasilar dolichoectasia: diagnostic and therapeutic considerations

Obstructive hydrocephalus caused by vertebrobasilar dolichoectasia is an extremely rare entity. Cerebrospinal fluid pathway obstruction may be localized at the level of either the foramina of Monro or the cerebral aqueduct. Radiological imaging can sometimes be misleading in establishing the precise location of the obstruction, which is crucial in determining the optimal surgical strategy. We report such a case with diagnostic challenges and also present a review of previously reported cases with a special focus on diagnostic and therapeutic controversies.

We present a patient with an obstructive hydrocephalus associated with a dolichoectatic basilar artery extending to the level of the foramina of Monro. Although computed tomography angiography findings indicate bilateral occlusion of the foramina of Monro by the posterior cerebral arteries, mild but suspicious dilatation of the third ventricle raised concerns about the precise location of the obstruction. Endoscopic exploration of the right foramen of Monro was performed not only to clarify questionable radiological findings but also to be prepared to make a septostomy prior to monoventriculoperitoneal shunting if exploration would confirm occlusion of the foramina of Monro. However, the right foramen of Monro was documented to be patent during surgery and the cerebral aqueduct was considered to be the location of obstruction. The procedure was accomplished with monoventriculoperitoneal shunting, which achieved a full recovery immediately after the operation.

Our current experience and the literature review highlight the usefulness of neuroendoscopy as a diagnostic and therapeutic solution, particularly in cases considered to have obstructive hydrocephalus caused by compression of the foramina of Monro by dolichoectatic basilar artery.