Parasellar syndromes

Abstract

The parasellar compartments are located lateral to and on either side of the sella turcica. The cavernous sinuses are the most prominent anatomic feature of the parasella. Each sinus consists of a plexus of veins through which runs the intracavernous portion of the internal carotid artery. Ocular motor nerves three and four travel within the dural covering of the cavernous sinus to the superior orbital fissure, and cranial nerve six travels through the carotid sinus itself, giving rise to parasellar syndromes, which have distinctive clinical features. Ophthalmoplegia occurs as a result of damage to these ocular motor nerves and variable involvement of oculosympathetic nerves. Facial pain, dysesthesia, and paraesthesia are caused by damage to one or more of the divisions of the fifth cranial nerve, travelling in the dural wall of the cavernous sinus. Tumors, such as meningiomas, frequently cause parasellar syndromes, as do aneurysms of the intracavernous portion of the internal carotid artery, carotid-cavernous fistulas, and cavernous sinus thrombosis. Inflammatory conditions such as Tolosa-Hunt syndrome, ischemia to small vessels supplying the cavernous portion of the cranial nerves, and infections can cause this syndrome. Magnetic resonance imaging is the investigation of choice and therapy is specific to the cause of the parasellar syndrome, but now includes more aggressive endoscopic and microsurgical intervention, and radiosurgery.

An approach to the patient with painful ophthalmoplegia, with a focus on Tolosa-Hunt syndrome

“…1 and 2) [1][2][3][4][5]6••]. Pain and oculomotor symptoms or signs can also occur secondary to lesions in the orbit.…”

Sellar and Parasellar Imaging

“…92 Most skull base metastases probably spread hematogenously, although seeding may also occur through the valveless Batson venous plexus, which connects the pelvic and thoracic venous systems with intracranial veins and sinuses. 92,93 Additionally, the skull base can be involved by direct extension of nasopharyngeal or sphenoid tumors or via perineural spread, commonly along branches of CN V. 94,95 Infiltration can lead to a distinct parasellar syndrome, with neuropathies frequently involving CNs III and V. 96 On MRI, osseous metastases are typically identified as hypointense geographic areas of marrow replacement on noncontrast T1-weighted sequences. Because marrow fat is normally hyperintense on both T1-and T2-weighted sequences, fat saturation is useful to visualize NEUROSURGERY VOLUME 80 | NUMBER 1 | JANUARY 2017 | 29…”

Imaging the cranial nerves: Part I: Methodology, infectious and inflammatory, traumatic and congenital lesions

“…Cranial nerves most commonly affected are, in decreasing order of frequency, the facial nerve in its intratemporal segments, the trigeminal nerve and oculomotor nerves within the cavernous sinus, the lower cranial nerves at the jugular foramen and the optic nerve at the orbital apex. Clinically, patients manifest with various syndromes: petrous apex/ Gradenigo's, cavernous sinus, jugular foramen/Vernet's and orbital apex/Tolosa-Hunt syndromes, respectively [20]. Necrotizing or malignant otitis externa, a Pseudomonas aeruginosa infection afflicting predominantly diabetic patients, is associated with the highest rate of facial nerve involvement, an ominous prognostic sign [5,11,12].…”