Onyx is a liquid embolic agent that is effective in the treatment of CCFs but not without hazards. Postembolization cavernous sinus thrombosis and swelling may result in transient compressive cranial neuropathies. The inherent gradual polymerization properties of Onyx allow for casting of the cavernous sinus but may potentially result in deep penetration within arterial collaterals that can cause CN ischemia/infarction. Although not proven, the angiotoxic effects of dimethyl sulfoxide may also play a role in postembolization CN deficits.

Eagle syndrome is an uncommon entity but is well known in the otorhinolaryngology and oral surgery literature. This syndrome results from the compression of cranial nerves in the neck by an elongated styloid process causing unilateral cervical and facial pain. The styloid process can also cause compression of the cervical carotid arteries leading to the so-called carotid artery syndrome together with carotidynia or neurological symptoms due to flow reduction in these arteries. The authors discuss the case of a 70-year-old man who suffered from transient ischemic attacks on turning his head to the left, with immediate remission of symptoms when his head returned to the neutral position. The patient was studied with dynamic angiography, which clearly showed focal flow restriction. Once a diagnosis was made, the styloid process was removed surgically and the patient completely recovered from his symptoms. A postoperative angiogram demonstrated complete resolution of the pathology. Neurosurgeons might encounter patients with Eagle syndrome and should be aware of the symptoms and signs. Once the diagnosis is made, the treatment is clear and very effective.

Embolization of vascular tumors with Onyx can be performed safely but may not reach optimal effectiveness in reducing intraoperative EBL if the embolic material does not penetrate the tumor vasculature. In the authors' experience, the best method of intraparenchymal penetration is achieved with direct tumor puncture. Transarterial embolization may not result in tumor penetration, particularly when injected from a long distance through small caliber or slow flow vessels.

Glioblastoma (GBM) rarely presents as an infratentorial tumor in adults. The authors present a case of concomitant supratentorial and infratentorial GBM in an adult. A 72-year-old man presented with headache, nausea, vomiting, and lightheadedness. Initial MR images revealed enhancing masses in the right cerebellum and right posterior periventricular region. The patient underwent a suboccipital craniotomy and resection of the cerebellar lesion. Final histopathology was consistent with glioblastoma. The patient went on to receive standard radiation treatment for GBM with concurrent and adjuvant temozolomide. However, the patient experienced clinical deterioration within a few days after starting radiotherapy. He and his family decided to forego treatment and pursue palliative care. The patient expired three months after the initial diagnosis. Autopsy findings supported the diagnosis of GBM with leptomeningeal gliomatosis and involvement of the cerebrum, cerebellum, and spinal cord. The authors review the literature and propose that the pathogenesis of multiple and multicentric GBM may involve neural stem cells within the subventricular zone or could result from tumor dissemination along established CNS routes, such as white matter tracts and CSF pathways.