Geometry and Symmetry of Willis' Circle and Middle Cerebral Artery Aneurysms Development.

Background: A relationship between the geometry and symmetry of Willis' circle and intracranial aneurysms was reported for anterior communicating and posterior communicating (PCom) aneurysms. A similar association with the middle cerebral artery (MCA) aneurysms instead appeared weaker. Methods: We reviewed 432 patients from six Italian centers with unilateral MCA aneurysms, analyzing the relationship between the caliber and symmetry of Willis' circle and the presence of ruptured and unruptured presentation. CT-angiograms were evaluated to assess Willis' circle geometrical characteristics and the MCA aneurysm side, dimension and rupture status. Results: The hypoplasia of the first segment of the anterior cerebral artery (A1) was in approximately one-quarter of patients and PCom hypoplasia was in almost 40%. About 9% had a fetal PCom ipsilaterally to the aneurysm. By comparing the aneurysmal and healthy sides, only the PCom hypoplasia appeared significantly higher in the affected side. Finally, the caliber of the internal carotid artery (ICA) and the first segment of MCA (M1) caliber were significantly greater in patients with unruptured aneurysms, and PCom hypoplasia appeared related to the incidence of an ipsilateral MCA aneurysm and its risk of rupture. Conclusions: Although according to these findings asymmetries of Willis' circle are shown to be a risk factor for MCA aneurysm formation and rupture, the indifferent association with ipsilateral or contralateral hypoplasia remains a datum of difficult hemodynamic interpretation, thereby raising the concern that this association may be more casual than causal.

The "state of the art" of intraoperative neurophysiological monitoring: An Italian neurosurgical survey.

Introduction: Intraoperative Neurophysiological Monitoring (IOM) is widely used in neurosurgery but specific guidelines are lacking. Therefore, we can assume differences in IOM application between Neurosurgical centers. Research question: The section of Functional Neurosurgery of the Italian Society of Neurosurgery realized a survey aiming to obtain general data on the current practice of IOM in Italy. Materials and methods: A 22-item questionnaire was designed focusing on: volume procedures, indications, awake surgery, experience, organization and equipe. The questionnaire has been sent to Italian Neurosurgery centers. Results: A total of 54 centers completed the survey. The annual volume of surgeries range from 300 to 2000, and IOM is used in 10-20% of the procedures. In 46% of the cases is a neurologist or a neurophysiologist who performs IOM. For supra-tentorial pathology, almost all perform MEPs (94%) SSEPs (89%), direct cortical stimulation (85%). All centers perform IOM in spinal surgery and 95% in posterior fossa surgery. Among the 50% that perform peripheral nerve surgery, all use IOM. Awake surgery is performed by 70% of centers. The neurosurgeon is the only responsible for IOM in 35% of centers. In 83% of cases IOM implementation is adequate to the request. Discussion and conclusions: The Italian Neurosurgical centers perform IOM with high level of specialization, but differences exist in organization, techniques, and expertise. Our survey provides a snapshot of the state of the art in Italy and it could be a starting point to implement a consensus on the practice of IOM.

Comparison Between Intrasylvian and Intracerebral Hematoma Associated with Ruptured Middle Cerebral Artery Aneurysms: Clinical Implications, Technical Considerations, and Outcome Evaluation.

BACKGROUND: Subarachnoid hemorrhage (SAH) due to a middle cerebral artery (MCA) aneurysm rupture is often associated with an intracerebral hematoma (ICH) or intrasylvian hematoma (ISH). METHODS: We reviewed 163 patients with ruptured MCA aneurysms associated with pure SAH or SAH plus ICH or ISH. The patients were first dichotomized according to the presence of a hematoma (ICH or ISH). Next, we performed a subgroup analysis comparing ICH versus ISH to explore their relationship with the most relevant demographic, clinical, and angioarchitectural features. RESULTS: Overall, 85 patients (52%) had a pure SAH, and 78 (48%) had presented with an associated ICH or ISH. No significant differences were observed in the demographics or angioarchitectural features between the 2 groups. However, the Fisher grade and Hunt-Hess score were higher for the patients with hematomas. A good outcome was observed in a higher percentage of patients with pure SAH compared with those with an associated hematoma (76% vs. 44%), although the mortality rates were comparable. Age, Hunt-Hess score, and treatment-related complications were the main outcome predictors on multivariate analysis. Patients with ICH appeared worse clinically compared with those with ISH. We also found that older age, a higher Hunt-Hess score, larger aneurysms, decompressive craniectomy, and treatment-related complications were associated with poor outcomes among the patients with an ISH, but not an ICH, which appeared, per se, as a more severe clinical condition. CONCLUSIONS: Our study has confirmed that age, Hunt-Hess score, and treatment-related complications influence the outcome of patients with ruptured MCA aneurysms. However, in the subgroup analysis of patients with SAH associated with an ICH or ISH, only the Hunt-Hess score at onset appeared as an independent predictor of the outcome.

Acute onset of paraplegia due to melanocytic cervicodorsal lesion.

BACKGROUND: Melanocytomas are rare pigmented tumors of the central nervous system (CNS). They are more frequent in females in their fifties and are typically benign, but locally aggressive lesions that very are rarely found in the spine. They can occur in all the age groups. CASE DESCRIPTION: A 62-year-old male presented with acute paraplegia a attributed to a C7-T1 intradural extramedullary melanocytoma. Urgent surgery, consisting of subtotal removal of the lesion, resulted in subtotal recovery of motor function with full resolution of his sensory deficit. Histologically, the lesion proved to be a melanocytoma. CONCLUSION: Rarely, patients with intradural extramedullary melanocytomas of the spine may present with acute paralytic deficits warranting emergent surgical intervention.