153 research outputs found
Nitric oxide synthase and cytochrome c oxidase changes in the tumoural and peritumoural cerebral cortex.
No full textTreatment of cerebral arteriovenous malformations
No full textEven today, arteriovenous malformations (AVM) are one of the most complex conditions encountered in neurosurgical practice. The difficulty in treatment is not confined to surgical resection of the AVM, but also affects the indications for treatment and the type of appropriate therapy. Each treatment aims at complete exclusion of the AVM. Partial resection has no significant effect on the risk of bleeding. Despite ongoing attempts to devise treatment protocols, each patient presenting an AVM is different and each individual case needs to be assessed by a team familiar with this type of lesion and aware of the percentage risk to the patient in proposing a treatment. A recent evaluation of numerous surgical series demonstrated an operative mortality for AVMs of different sizes at 3.3%. Post-operative angiography only displays complete exclusion of the AVM in 97% of cases. The aim of endovascular treatment is to exclude the nidus. If this is not achieved, the AVM will revascularize sooner or later. Endovascular treatment alone seldom results in complete occlusion of the AVM. Some literature reports describe a high mortality rate linked with endovascular treatment with percentages of around 1.6% with a 12.8% morbidity. In our experience, the morbidity linked to endovascular treatment is below 4%. Complications linked to radiosurgery are extremely rare. The main problem of radiosurgery with LINAC or gamma knife is the possibility of treating only small AVM successfully. From November 1991 to August 2001, AVM were found in 115 cases out of 1137 patients admitted for vascular malformations (10%). Of these, 93 (81%) had supratentorial AVM whereas 22 (19%) had subtentorial lesions. Treatment (surgery, embolisation, radiosurgery or a combination) was carried out in 94 cases (82%). Of the nine patients with non-bleeding AVM who did not receive treatment for various reasons, none experienced haemorrhage in the follow-up period of one to ten years. Of the 94 patients who had had a haemorrhage, 12 presented rebleeding of the AVM (13%). In an overall analysis of our results irrespective of the type of treatment and including untreated patients, 67 out of 115 (59%) were discharged without neurological deficit (good outcome). Overall morbidity was 29%; 14 patients died, giving a mortality rate of 12%. The decision how to treat each individual patients is taken after discussion with neuroradiologists and radiosurgeons. In general, in the cases referred to us, we acted as follows: - In superficial AVM less than 25-30 cm3 in non-eloquent brain areas, the lesion was treated surgically. - In AVM on the mesial face of the hemisphere or involving the cingulate or corpus callosum regions, direct obliteration was performed in six cases whereas three were treated by radiosurgery. - Deep para or intraventricular AVM or caudate nucleus or striocapsulothalamic lesions were usually treated by radiosurgery preceded by partial embolisation. - Small AVM in eloquent areas were treated by radiosurgery whereas large lesions were first treated by embolisation followed by radiosurgery. - AVM close to eloquent areas were usually treated surgically, possibly after endovascular therapy
Recent therapeutic strategies for spinal cord injury treatment: possible role of stem cells.
No full textOnline Efficiency Optimization Technique for Digitally Controlled Resonant DC/DC Converters
No full textThis paper proposes a digital online efficiency optimization
technique for DC/DC Dual Half-Bridge Series Resonant Converters. The proposed technique implements an advanced
modulation scheme which exploits the degrees of freedom inherently available in the converter modulation space in order
to simultaneously regulate the output voltage and maintain
the system in its maximum efficiency point. Furthermore, the
proposed multivariable control technique robustly brings the
converter back to maximum efficiency even in presence of abrupt load changes. The proposed efficiency optimization approach is first discussed theoretically, then via simulation and experimental tests. Experimental results on a 5 V, 1.2 A, 200 kHz series resonant converter prototype are in line with the theoretical predictions and confirm both the feasibility and the effectiveness of the approach. Experimental efficiency measurements indicate an efficiency improvement from η = 30% to more than η = 80% in light load conditions
Automated end-to-side anastomosis to the middle cerebral artery with C-Port xA: A feasibility study on human cadavers
No full textGliomi Dell'insula E Parainsula ( Tipo Terzo Secondo Yasargil ): Sopravvivenza Dopo Rimozione Chirurgica
No full textThe use of intraventricular instillation of vancomycin to prevent external ventricular drainage related infection: a clinical prospective study
No full textBackground: External ventricular drainage (EVD)-related infection (ERI) represents an important condition with potential high morbidity with significant impact on patient outcomes. Prophylactic systemic antibiotics are routinely administered to patients with EVD, but they do not significantly lower the incidence of ERIs. Intraventricular treatment with vancomycin appeared to be safe and effective, but most reports are case-reports/-series and retrospective studies. Methods: A prospective non-randomized case-control study was conducted in a consecutive series of 116 patients treated with EVD insertion. The study includes the group of patients treated with intrathecal vancomycin (Group A, 62 patients) compared with the control group treated with daily intravenous cefazolin (Group B, 54 patients). Results: No statistically significant differences were found between the 2 groups with regard to the duration of catheterization and occurrence of ERI during hospitalization. EVD was replaced in 16 cases (25.8%) in group A and in 12 cases (22.2%) in the control group B (P 0.67). Three cases (4.8%) of ERI have been found in group A and 5 (9.3%) in the control group (P = 0.34). All reported cases of infection in group A were caused by gram-negative agents; on the opposite, cases of infections in the control group B were caused above all by gram-positive bacteria with a statistical difference (P = 0.03). Conclusions: In this first prospective study on this topic, we found that intrathecal Vancomycin administration in EVDs does not reduce the occurrence of ERI compared with intravenous cefazolin prophylaxis, but induces selection of gram-negative bacteria
Approccio Transbasale Mediano Ai Meningiomi Della Doccia Olfattoria: Aspetti Tecnici Basati Su Una Esperienza Di 21 Casi
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