Arterial supply of the upper cranial nerves: a comprehensive review.

The arterial supply to the upper cranial nerves is derived from a complex network of branches derived from the anterior and posterior cerebral circulations. We performed a comprehensive literature review of the arterial supply of the upper cranial nerves with an emphasis on clinical considerations. Arteries coursing in close proximity to the cranial nerves regularly give rise to small vessels that supply the nerve. Knowledge of the arteries supplying the cranial nerves is of particular importance during surgical approaches to the skull base.

[Quantitative analysis of vascular network of oculogyric nerve nuclei].

INTRODUCTION: Nuclei of oculogyric nerves (principal oculomotor nucleus, trochlear nucleus and abducens nucleus) are densely vascularized brainstem structures. The aim of this study was to determine quantitative characteristics of the vascular network of these nuclei. MATERIAL AND METHODS: The study was done on 30 adult brainstems, both male and female, without diagnosed neurological disturbances. Three-millimetre-thick stratums were taken in transversal plane and cut in 0.3 micrometer semi-serial sections stained with Mallory method. The images of studied nuclei were taken with "Leica" DM 1000 microscope and "Leica" EC3 digital camera under 400x magnification, and analyzed by ImageJ software with A 100 grid. The statistical analysis was performed by Statistical Package for the Social Sciences software with 5% level of significance. RESULTS: A statistically significant difference was found in the volume and surface density between principal oculomotor nucleus and trochlear nucleus, and between trochlear nucleus and abducens nucleus. No difference was found in the length density. DISCUSSION: The results of this research match the results of studies on characteristics of vascular network of oculogyric nerve nuclei, while the comparison of vascular networks of these nuclei, substantia nigra, vestibulocochlear nuclei and precentral gyrus illustrates differences in quantitative characteristics of blood vessels in these structures. CONCLUSION: Blood vessels of principal oculomotor nucleus and abducens nucleus have similar dimensions and approximately the same arborization pattern, while vessels of trochlear nucleus have significantly smaller dimensions and density.

Development of cranial nerve palsy shortly after endosaccular embolization for asymptomatic cerebral aneurysm: report of two cases and literature review.

CLINICAL DESCRIPTION: We report two cases of asymptomatic cerebral aneurysm in which cranial nerve palsy (CNP) developed shortly after symbolization. The CNP occurred immediately in case 1, but case 2 showed the CNP 30 h after symbolization. Although both aneurysms had increased in size on follow-up angiography, case 2 who showed dome re canalization resulted in progressive CNP deterioration. CONCLUSION: These findings suggest that the CNP may result not only from mechanical compression by coils but also from inflammation induced by perpendicular thrombosis, and that the prognosis of the CNP may be influenced by dome re canalization. This complication should be kept in mind in treatment for asymptomatic aneurysms adjacent to the cranial nerves.

A sweet case of bilateral sixth nerve palsies.

A 70-year-old woman with a history of diabetes mellitus and arterial hypertension presented with bilateral abduction deficits consistent with bilateral sixth nerve paresis. A diagnostic evaluation including magnetic resonance imaging and lumbar puncture was unrevealing. The bilateral sixth nerve paresis spontaneously resolved suggesting ischemic or microvascular disease as the underlying etiology.

Periodic abducens nerve palsy in adults caused by neurovascular compression.

Unilateral abducens nerve palsy with periodic recurrences is a well-recognised finding in children, but is rare in adults. The underlying pathophysiological mechanism is unknown. Vascular compression of the nerve is suspected but never demonstrated. We describe an adult patient with, altogether, 11 periods of unilateral right-sided abducens palsy and arterial contact at the root exit zone of the symptomatic side.

Transient diplopia following maxillary local anesthetic injection.

A 36-year-old female patient developed diplopia and an ipsilateral lateral rectus paresis following local anesthetic administration to remove a left maxillary second molar. Complete resolution occurred within 3 hours. The clinical examination and management plan are reviewed for this uncommon occurrence. The relevant anatomical pathways are discussed and illustrated with photographs.

Saccade dynamics in peripheral vs central sixth nerve palsies.

OBJECTIVE: To investigate differences between peripheral idiopathic and central sixth nerve palsies from brainstem damage by comparing peak velocities and durations of horizontal saccades. METHODS: Fourteen patients with unilateral incomplete sixth nerve palsies caused by idiopathic, presumed ischemic, peripheral damage, 5 with incomplete central (fascicular) palsy caused by brainstem lesions, and 10 controls were studied. Palsies under 1 month in duration were designated as acute and those of longer duration were chronic. Among peripheral palsies, five were acute, nine were chronic. Among central palsies, two were acute, three were chronic. Subjects made +/- 10 deg horizontal saccades while wearing search coils. Serial recordings were made in seven patients with acute palsy (five peripheral, two central). RESULTS: Centrifugal abducting saccadic velocities in the paretic eye were subnormal in both central and peripheral acute palsies, as anticipated from lateral rectus weakness. In chronic central palsies, abducting velocities in the paretic eye remained reduced. However, in chronic peripheral palsies, velocities became normal in the tested range of excursion, within 2 months of onset, despite persisting abduction deficit. CONCLUSIONS: Saccade peak velocities are reduced and their durations are prolonged in the field of action of acutely palsied peripheral and central nerves. Speeds remain reduced in chronic central (fascicular) palsies, consistent with limited regeneration within the brain. Saccade speeds are repaired in chronic peripheral palsies, probably by remyelination and axonal regeneration, and perhaps also by central monocular adaptation of innervation selectively to the paretic eye, in order to drive both eyes rapidly and simultaneously into the paretic field of motion.

The ophthalmology of internal carotid artery dissection.

PURPOSE: Carotid dissection is an important cause of cerebral and retinal ischemic symptoms, especially in young adults. This article presents a patient material and also includes a review of the ophthalmologic signs and symptoms of carotid dissection. MATERIAL AND METHODS: Twenty-eight patients with spontaneous dissection of the extracranial internal carotid artery dissection underwent a neuro-ophthalmological examination. RESULTS: Twenty-three patients had oculosympathetic paresis. Two experienced transient monocular blindness; in one the episodes were provoked by sitting up from a supine position. One patient presented with a monocular visual field defect, due to posterior ischemic neuropathy, and two others with homonym hemianopia. Diplopia, caused by an incomplete VIth cranial nerve palsy was recognised in one. CONCLUSION: All but one patient presented with detectable ophthalmologic symptoms or signs. Very often the ophthalmologist is the first medical contact for patients with internal carotid artery dissection. The condition is serious, and a prompt evaluation and treatment is indicated to prevent irreversible sequelae.

Progressive ophthalmoplegia with acute ischemic abducens nerve palsies.

PURPOSE: To determine the frequency of early progression of opthalmoplegia in patients with acute ischemic abducens nerve palsies. METHODS: Patients with ischemic abducens nerve palsy examined within one week from the onset of symptoms were identified using predetermined entry criteria and serially followed up using a standardized ophthalmoplegia grading scheme. RESULTS: Only two of the 35 patients initially had a complete abduction deficit. Of the 33 patients who initially had an incomplete abduction deficit, 18 (54%) showed progression of their ophthalmoplegia. CONCLUSIONS: Patients with acute incomplete ischemic abducens nerve palsies frequently demonstrate early progression of their ophthalmoplegia.

The neurovascular relationships and the blood supply of the abducent nerve: surgical anatomy of its cisternal segment.

Twenty-eight abducent nerves were examined after injecting india ink and gelatin into the vertebrobasilar arterial system. All the abducent nerves were found to be crossed and/or penetrated by the surrounding vessels. The ventral surface of the nerves was crossed by the anterior inferior cerebellar artery (AICA) (75.0%), the posterior inferior cerebellar artery (17.85%), the common trunk of the AICA and posterior inferior cerebellar artery (7.14%), the internal auditory artery (14.28%), the anterolateral artery (46.43%), the pontomedullary artery (92.86%), and the corresponding veins (46.43%). The dorsal surface of the cisternal segment was crossed by the AICA (35.71%), the inferolateral pontine artery (10.71%), the anterolateral artery (82.14%), and the certain veins (46.43%). Sixty-four percent of the cisternal segments were penetrated by one or more of the following vessels: the AICA (25.0%), the anterolateral artery (17.86%), the pontomedullary artery (3.57%), and/or by the corresponding veins (42.86%). The majority of the cisternal segments of the abducent nerves were supplied by the anterolateral arteries (85.71%), and only some of them by the AICA (14.29%) or the pontomedullary artery (7.14%). The authors discuss the possible clinical significance of the anatomical data.

The blood supply of the intracavernous cranial nerves: an anatomic study.

Cranial nerve deficits are the most common complications of cavernous sinus surgery. Often the deficit occurs despite anatomic preservation of the nerve, and ischemic injury is thought to be the cause. A better understanding of the blood supply of these nerves may help to prevent such complications. The authors performed a cadaveric microsurgical study of the intracavernous cranial nerves and their blood supply in 20 cavernous sinuses. The oculomotor nerve received branches from the inferolateral trunk or its equivalent in all specimens (100%). The proximal trochlear nerve received branches from the inferolateral trunk in 80% of the specimens and from the tentorial artery of the meningohypophyseal trunk in 20%. The distal half was supplied by the branches from the inferolateral trunk only. In the region of Dorello's canal, the proximal third of the abducens nerve received branches from the dorsal clival artery of the meningohypophyseal trunk. The middle and distal thirds received branches from the inferolateral trunk. The ophthalmic and proximal maxillary segments of the trigeminal nerve received branches from the inferolateral trunk. The distal maxillary segment was supplied by the artery of the foramen rotundum. In the majority of cases, the medial third of the Gasserian ganglion received branches from both the inferolateral trunk and the tentorial artery. The middle third of the ganglion received branches from either the inferolateral trunk or the middle meningeal artery. Our findings indicate the important role the intracavernous branches of the internal carotid artery play in the blood supply of the intracavernous cranial nerves, and stress the need to preserve these branches to prevent or minimize postoperative deficits.

Raymond's syndrome following petrosal sinus sampling.

Inferior petrosal sinus sampling (IPSS) is used to evaluate the pituitary-dependency of Cushing's disease, and to predict the laterality of a microadenoma prior to transsphenoidal operation. A serious complication occurred in a 14-year-old boy: he suffered brain stem ischaemia with abducens nerve palsy and hemiparesis (Raymond's syndrome). The case prompted us to reconsider the indication for this investigation.

The microsurgical anatomy of the abducens nerve in its intracranial course.

The microsurgical anatomy of the abducens nerve through its intracranial course was studied in 20 specimens obtained from 10 cadaver heads fixed in formalin. Another 20 specimens were used to study the pattern of branching of the nerve trunk. The following intracranial segments were studied: subarachnoid or intracisternal, petroclival, and intracavernous. Angulations, neurovascular relationships, and branching patterns of the nerve are described. The long intracranial course of the abducens nerve, its tortuosity, and its tight attachment to the skull base at the level of the petrous apex may influence its vulnerability in some pathological conditions.

Ischemic ("diabetic") cavernous sinus syndrome.

A 65-year-old diabetic woman presented with an acute cavernous sinus syndrome involving the right third, fifth, and sixth cranial nerves. The complete neuro-ophthalmic workup included high-resolution computed tomography, angiography, lumbar puncture, and laboratory studies, all of which were unrevealing. The cranial nerve palsies spontaneously resolved in 10 weeks, consistent with an ischemic etiology.

Oculomotor, trochlear, and abducens nerves penetrated by cerebral vessels. Microanatomy and possible clinical significance.

Twenty formaldehyde-fixed brains were examined under the stereoscopic microscope. In 12 brains (60%), the oculomotor nerves were penetrated by the circumflex mesencephalic artery or by a branch of the perforating vessels of the posterior cerebral artery, either on one side (40%) or on both (20%). In one brain (5%), a particular relationship was noticed between the trochlear nerve and the superior cerebellar artery. The abducens nerves were penetrated by the corresponding pontine veins in three brains (15%). These anatomical findings might have important clinical implications.