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.

Intramesencephalic course of the oculomotor nerve fibers: microanatomy and possible clinical significance.

Comprehension of the mesencephalic syndromes that affect oculomotor nerve fascicles requires a detailed knowledge of their relationship with the adjacent structures and the blood supply of the central midbrain region. This was the reasoning behind our study, which was performed in ten serially sectioned midbrains stained with cresyl violet and luxol fast blue, in three microdissected midbrains, and in two injected and cleared specimens. Three continuous groups of the intramesencephalic oculomotor nerve fascicles were distinguished: the caudal, intermediate and rostral. The caudal fascicles, which most likely innervate the superior rectus and the levator palpebrae superioris muscles, extend through the superior cerebellar peduncle just caudal to the red nucleus and close to the lateral lemniscus. The intermediate fascicles, devoted to the medial rectus and the inferior oblique muscles, always pass through the superior cerebellar peduncle, just medial to the caudal part of the red nucleus (60 %), and less frequently (40 %) through the nucleus itself. The rostral oculomotor fascicles, which terminate in the inferior rectus and sphincter pupillae muscles, course medial to the rostral part of the red nucleus. While the rostral and intermediate oculomotor fascicles are supplied only by the medial twigs of the paramedian mesencephalic perforating arteries, the caudal fascicles are also nourished by the lateral branches of the same perforating arteries. The data obtained form an important basis for the explanation of certain mesencephalic syndromes, and even anticipate some new syndromes not yet described in the literature.

[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.

The neurovascular relationships of the oculomotor nerve.

In this study, the arterial supply of the cisternal (initial) and the subcavernous parts of the oculomotor nerve (ON) and the relation between the nerve and adjacent vascular structures like posterior cerebral artery (PCA) and superior cerebellar artery (SCA) were investigated. A total of 140 formalin fixed hemispheres from 70 human cadaveric brains were examined. The nutrient branches reaching the cisternal and subcavernous parts of the ON were investigated, along with branches of adjacent vascular structures penetrating the nerve and passing through it. In the material examined, the ON, after arising from the midbrain, mostly continues laterally between PCA and SCA or between PCA and the rostral SCA trunk. However, in three hemispheres of our specimens, the ON run between the rostral and caudal SCA trunks. We observed that the branches of PCA-P1 segment supplied the cisternal part of the ON in all specimens. In one specimen, the cisternal part of the ON was supplied by a branch arising from the rostral SCA trunk which was also originating from PCA. Differently, in four hemispheres, branches arising from PCA or SCA perforated the cisternal part of the ON and passed through it. We also observed a tortuous caudal trunk of duplicated SCA in one of our specimens and considered it as a rare variation. The anatomy of the ON and its vascular relations is significant in terms of not only understanding the compression syndromes and its vascular dysfunctions, but the exact diagnosis and treatment as well.

Pain in ischaemic ocular motor cranial nerve palsies.

AIM: Pain is a common feature of microvascular ischaemic ocular motor cranial nerve palsies (MP). The natural history of pain in this condition has not been studied. The purpose of this report is to define the spectrum of pain in isolated MP, with special reference to diabetic versus non-diabetic patients. DESIGN AND METHODS: Retrospective and prospective chart review was performed on 87 patients with acute-onset MP of a single cranial nerve (CN III, oculomotor; CN IV, trochlear; CN VI, abducens) that progressively improved or resolved over 6 months. RESULTS: Five of the 87 patients had two events, making the total number events 92. There were 39 (42.4%) CN III palsies, five (5.4%) CN IV palsies and 48 (52.2%) CN VI palsies. Thirty-six (41%) patients had diabetes. Pain was present in 57 (62%) events. The majority of diabetic and non-diabetic patients had pain. Pain preceded diplopia by 5.8 (SD 5.5) days in one-third of events. There was a trend towards greater pain with CN III palsies, but this was not statistically significant. Patients who experienced severe pain tended to have pain for a longer duration (26.4 (SD 21.7) days compared with 10.8 (SD 8.3) and 9.5 (SD 9) days for mild and moderate pain, respectively). There was no correlation between having diabetes and experiencing pain. CONCLUSIONS: The majority of MP are painful, regardless of the presence or absence of diabetes. Pain may occur prior to or concurrent with the onset of diplopia. Non-diabetic and diabetic patients presented with similar pain characteristics, contrary to the belief that diabetic patients have more pain associated with MP.

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.

Anatomical features of the cisternal segment of the oculomotor nerve: neurovascular relationships and abnormal compression on magnetic resonance imaging.

OBJECT: The object of this study was to assess the detailed anatomical features and vascular relationships of the cisternal segment of the oculomotor nerve, and to assess the utility of MR imaging in oculomotor nerve palsy caused by abnormal compression related to arteries and tumors. METHODS: The anatomy of the oculomotor nerve was depicted using 3D Fourier transformation constructive interference in steady-state (CISS) MR imaging in 196 volunteers (392 total nerves), in 9 patients with paralysis of the oculomotor nerve, and in 1 preoperative patient with cholesteatoma in the pontine cistern. The vessels adjacent to the oculomotor nerve were detected and compared using 3D time-of-flight MR imaging. The 3D CISS multiplanar reconstruction (MPR) images of the oculomotor nerve in cadavers and in specimens from the cadavers were used to verify the oculomotor nerve shown in the 196 patients. The images were assessed with respect to the demonstration of the oculomotor nerve, the optimal display angles on MPR images, the visualized length of the nerve, neurovascular relationships, and abnormal compression caused by arteries and tumors. RESULTS: Three-dimensional CISS MR imaging depicted the cisternal segment of the oculomotor nerve with certainty in 100% of the patients in the transverse, sagittal, and coronal planes. Three-dimensional CISS imaging of the oculomotor nerve in 196 volunteers revealed similar results corresponding to 3D CISS MPR images of cadavers and cadaver specimens. The maximum visualized length of the oculomotor nerve was 14.61 +/- 2.33 mm. The angle between the oculomotor nerve and the median sagittal plane was 24.48 +/- 4.57 degrees on the left and 24.48 +/- 5.07 degrees on the right. The posterior cerebral artery was observed to contact the oculomotor nerve in 216 (55.1%) of 392 nerves, and the superior cerebellar artery was observed to contact the oculomotor nerve in 231 (58.9%) of 392 nerves. The abnormal nerve compression in 9 patients with paralysis of the oculomotor nerve was displayed well in all patients. The adjacent relationship of the oculomotor nerve in 1 preoperative patient with cholesteatoma in the pontine cistern was also demonstrated clearly. CONCLUSIONS: Use of 3D CISS sequences and 3D time-of-flight sequences enables accurate identification of the cisternal segment of the oculomotor nerve, neurovascular relationships, and abnormal compression caused by arteries and tumors.

Internal carotid artery occlusion manifesting only as oculomotor nerve palsy.

Oculomotor nerve palsy is very rare as the only manifestation of internal carotid artery (ICA) occlusion, and the angiographic findings have not been described in detail. We present a case of ipsilateral ICA occlusion manifesting as only sudden onset of oculomotor nerve palsy. Cerebral angiography showed occlusion of the ICA from the cervical portion to the ophthalmic portion. Distal blood flow was compensated through an anastomosis from other arteries. Ischemia of the oculomotor nerve was thought to be caused by loss of supply from branches arising from the occluded cavernous portion of the ICA.

Relationship between the posterior cerebral artery and the cisternal segment of the oculomotor nerve.

The aim of this study was to evaluate the relationship between the cisternal segment of the oculomotor nerve and the posterior cerebral artery and its branches. The oculomotor nerve and the posterior cerebral artery of 15 cadaver brains (30 hemispheres) were examined using a surgical microscope. The dorsal portion of the cisternal segment of the oculomotor nerve had a close relationship with the P(1) and P(2) segments of the posterior cerebral artery in 100% of cases, the thalamoperforating arteries in 97%, the collicular arteries in 97%, the short circumferential arteries in 33% and the posterior medial choroidal arteries in 20%. The proximal portion of the nerve had a close relationship with the P(1) segment of the posterior cerebral artery, the thalamoperforating arteries, the collicular arteries and the short circumferential arteries, whereas the distal portion had a close relationship with the P(2) segment of the posterior cerebral artery and the posterior medial choroidal arteries. The oculomotor nerve was perforated by various arteries in different portions. These arteries were the thalamoperforating arteries in 10% of the hemispheres, the collicular arteries in 16% and the short circumferential arteries in 11%. It can be concluded that the dorsal portion of the cisternal segment of the oculomotor nerve has a close relationship with the branches arising from the P(1) and P(2) segments of the posterior cerebral artery. These arteries supply the cisternal segment of the oculomotor nerve.

[Pupil-sparing painful oculomotor neuropathy due to a carotico-cavernous aneurysm]. / Ophtalmoplégie extrinsèque pure douloureuse du nerf moteur oculaire commun révélant un anévrysme de la carotide.

INTRODUCTION: In third cranial nerve palsy, the lack of mydriasis evokes a noncompressive mechanism. Case report. We report a case of a slightly painful, pure extrinsic third-nerve palsy, complete except for the partial ptosis secondary to the compression by an intracavernous carotid aneurysm. Percutaneous endovascular embolization was followed by complete regression of the palsy within 4 weeks. The pupil may have been spared by the mechanism of compression after the separation of the pupillomotor and extrinsic fibers or the ischemia of the third nerve by its arterial trunk lesion. CONCLUSION: This case report underlines that brain radiological explorations are necessary in some third-nerve pupil-sparing palsies.

Clipping vs coiling of posterior communicating artery aneurysms with third nerve palsy.

The authors investigated the evolution of third nerve palsy in patients with posterior communicating artery aneurysms who underwent coiling vs clipping. There was no statistical difference of complete third nerve palsy recovery in both treatments. Both techniques were of clinical benefit. Older age, diabetes, delayed interventions, and complete third nerve palsy at presentation indicated a poor prognosis for recovery.

[An ischemic syndrome of the oculumotor nucleus: associated clinical and anatomical variations on a theme]. / Syndrome nucléaire du nerf oculo-moteur commun (III) d'étiologie ischémique: variations cliniques et anatomiques associées.

Nuclear syndrome of the oculomotor nerve was first described in 1981, it is characterized by the association of an ipsilateral third nerve palsy with a paresis of elevation in the contralateral eye. This syndrome can be caused by vascular or tumoral lesions in the upper midbrain. It is rarely due to ischemic unilateral mesencephalic lesions, because ischemic lesions of the midbrain are usually integrated in a diffuse involvement of the brainstem and the thalamo-sub-thalamic region. In case of nuclear syndrome of the third nerve due to isolated upper midbrain infarct in the paramedian territory, dependent on branches of the basilar artery, oculomotor symptoms are frequently isolated. On the contrary, in fascicular syndromes of the third nerve, resulting from stroke in more lateral territories upon branches of the posterior cerebral artery, many neurological symptoms are associated with the oculomotor signs. We describe 3 patients presenting with a characteristic nuclear syndrome of the third nerve, resulting from a unilateral paramedian ischemic stroke in the upper midbrain, confirmed by cerebral CT scan or MRI examination. Clinical presentation differed in each case, and marked contralateral hemiparesia, cerebellar syndrome and focal asterixis were associated in various ways with the stereotyped oculomotor disorders. In the 3 cases, the nuclear syndrome of the third nerve was associated with fascicular involvement of the nerve, in an unusual clinical picture. The theoretical distinction between nuclear and fascicular syndromes is supported by the anatomical description of the arterial segmentation in the upper midbrain, which remains debated since the first description. According to the variability of clinical presentations, it seems that the arterial territories may be more variable than initially described. Therefore, ischemic lesions of the upper midbrain may involve some vascular borderzones with a high inter-individual variability. Upper midbrain strokes may thus lead to variable clinical pictures.