Surgical treatment of a rare congenital anomaly of the vertebral artery: case report and review of the literature.

A case of an abnormal loop of the vertebral artery compressing both the cervicomedullary junction and the accessory nerve is reported. The embryological development of the vertebrobasilar system may explain this anatomical anomaly. The possibility of an abnormal location of the vertebral artery may complicate the lateral C1-C2 puncture for myelography. Only five similar cases have been reported previously, but none of them presented any clinical symptomatology, and surgical treatment was never required. The present patient was cured by microvascular decompression. The pathogenetic and surgical implications are discussed in light of the literature.

Microsurgical anatomy of the cisternal course of the perforating branches of the posterior communicating artery.

Both the perforating branches--especially the extracerebral segments--and the arachnoidal anatomy at the level of the posterior communicating artery were studied in 60 human brains previously fixed in formalin. The close relationships between this artery and the oculomotor nerve are described, and it is noted that each of them is enclosed in its own arachnoidal compartment, which in the case of the posterior communicating artery is to be distinguished from the interpeduncular cistern. The latter cistern was found to contain only the terminal segments of the posterior communicating artery. The hypothalamic branches were within the inner wall of the arachnoidal cistern surrounding the posterior communicating artery. The variations in diameter of this artery are explained by its embryological development and are not related to the number and the diameter of the perforators. The posterior communicating artery was absent at times. The surgical implications of such a variable anatomical arrangement are discussed in the light of the literature.

Association between an aneurysm of the anterior inferior cerebral artery and an arteriovenous malformation fed by the same artery.

An unusual case of distal aneurysm of the anterior inferior cerebellar artery (AICA) associated with a cerebellar arteriovenous malformation in a 35 year-old woman is reported. The clinical presentation was a subarachnoid hemorrhage, that is the sudden onset of headache while she was driving her car. In the following days the patient experienced a cerebellopontine angle syndrome: unsteadiness, tinnitus and hearing loss in her left ear, along with drop episodes. All symptoms disappeared in about a week. She consulted a neurosurgeon only a month later. On the day of admission in the Neurosurgical Department of Résidence du Parc Clinic her neurological status was normal. Neuroradiological investigations showed the association between the two distal AICA malformations. At surgery it was possible either to clip the aneurysm or to remove the AVM. The origin of the hemorrhage has not been clearly identified. The patient had an uneventful recovery and returned to her job three months later. The aneurysm was located on the same artery that supplied the AVM. This association is rare at the AICA level. The possible development of the aneurysm induced by increase in flow through the AVM is discussed in the light of Literature data.

Modalities of origin of the middle cerebral artery. Incidence on the arrangement of the perforating branches.

In a series of 100 anatomical dissections on the basal brain arteries a case of real duplication at the middle cerebral artery level has been found. The importance of such a finding is discussed in the light of literature data. The knowledge of similar anatomical patterns is fundamental in the study of the lenticulostriate arteries arising from the sphenoidal segment of the middle cerebral artery. In fact the neurosurgeon must be familiar with all the possible variations of these perforators, given that the opening of the Sylvian fissure is by now an obligatory manoeuvre for the transcisternal access to the circle of Willis.

Extracerebral course of the perforating branches of the anterior communicating artery: microsurgical anatomical study.

Damage to the perforating branches arising from the anterior communicating artery, because of their blood supply to the septal nuclei and anterior hypothalamus, explains the memory impairment and the electrolyte disturbances that often follow the surgery of aneurysms located in this part of the circle of Willis. The microsurgical anatomy of these branches was studied on 60 fixed human brains, with special attention to their number, caliber, and vascular territory. The direction of the branches was evaluated, measuring the angle formed by them with the postcommunicating segment of the anterior cerebral artery. The variability of this anatomical region is discussed in light of the literature.

[Hydrocephalus and cerebral cysticercosis. A case report. Review of the literature]. / Hydrocéphalie et cysticercose cérébrale. A propos d'un cas. Revue de la littérature.

A case of intraventricular and cisternal cerebral cysticercosis with no intraparenchymatous involvement is reported. The clinical features were characterized by episodes of blockage of the C.S.F. pathways producing acute hydrocephalus. On three occasions surgical treatment was required: two ventriculoperitoneal shunts and a ventriculocisternostomy were performed. The intraventricular cystic membranes found during the third operation suggested the diagnosis. Epidemiological arguments, the pathogenesis of hydrocephalus and diagnostic and therapeutic aspects are discussed in the light of the literature data.

[Micro-anatomy of collateral perforating branches of the middle cerebral artery]. / Etude micro-anatomique des branches collatérales perforantes de l'artère cérébrale moyenne.

The lenticulostriate arteries are the subject of a microanatomical study on 50 formalin fixed human brains. A single trunk arising from the middle cerebral artery is rarely found. In fact the branches are numerous and they are found to ramify before penetrating the anterior perforated substance. The length of the sphenoidal segment is variable and this aspect is discussed in the light of the literature data. The origin of the perforating branches is spread from the internal carotid artery to the bifurcation branches of the middle cerebral artery (M2 segment). On the other hand lenticulostriate arteries arising from the cortical branches of the middle cerebral artery are often found. These anatomical patterns are of essentially surgical interest. No branches must be damaged during the opening of the Sylvian fissure or during the dissection of an aneurysm in this region.

[Arteriovenous malformations in children. A series of 61 cases]. / Malformations artério-veineuses de l'enfant. Une série de 61 cas.

A series of 61 cases of cerebral arteriovenous malformations(AVM) was observed in children under 15 years of age during the last 18 years; 7 concern infants under 12 months and more than 50% are children between 10 and 15 years old. Intra-cerebral hemorrhage was revealing in 45 cases (7.7%) and 12 patients were in comatose state at presentation; 8 children (1.1%) only presented epilepsy alone; 53 cases (86.8%) were operated upon and only one has had a partial removal; 2 children were cured by stereotactic radiosurgery; one child must be embolize and 5 children were not treated; 50 cases (82%) have a good or an excellent result with normal life; 7 cases (11.5%) have sequellae and only 4 children (6.5%) died.

Anomalies of the P1 segment of the posterior cerebral artery: early bifurcation or duplication, fenestration, common trunk with the superior cerebellar artery.

In a series of anatomical dissections on 100 fixed human brains, 3% of anomalies of the precommunicating segment of the posterior cerebral artery (P1) were found, among which a case of duplication of the P1 segment. This finding is very unusual and it is much rarer than the many other anatomical patterns reported in the circle of Willis. It is to be considered a very early bifurcation, as reported at the middle cerebral artery level. Another two unusual anatomical patterns were found. One was a large fenestration of the P1 segment, which is rather frequent in the vertebrobasilar system. The other was a bilateral common trunk between the posterior cerebral artery and the superior cerebellar artery, which represents a rare anatomical variation. The existence of such "anomalies" can be explained by the embryological development of the region. Their pathogenic and neurosurgical implications are discussed in the light of the literature.