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Background and Aims: Intraoperative MRI (ioMRI) consists of performing a MRI during brain or spinal surgery. Although it is a safe and useful technique, it is available in a few hospitals. This means some aspects are not perfectly defined or standardized, forcing each center to develop its own solutions. Our goal is to describe the technique, evaluate the changes made to optimize its use and thus be able to facilitate the intraoperative resonance implementation in other neurosurgery departments., Methods: A prospective analysis of patients consecutively operated using high-field ioMRI guidance was carried out, describing the type of tumor, clinical data, time and sequences of ioMR, use of intraoperative neurophysiology, preoperative tumor volume, after ioMR, and postoperative, as well as complications., Results: ioMR was performed in 38 patients selected from among 425 brain tumors (9%) operated on in this interval. The tumor types were: 11 glioblastomas, 8 anaplastic astrocytomas, 5 diffuse astrocytomas, 4 meningiomas, 3 oligodendrogliomas, 2 metastases, 2 epidermoid cysts, 1 astroblastoma, 1 arachnoid cyst and 1 pituitary adenoma. The mean age was 45 years. The mean preoperative tumor volume was 45.22cc, after the ioMR 5.08cc and postoperative 1.28cc. Resection was extended after ioMR in 76%. Gross total resection was achieved in 15 patients and residual tumor of less than 1cc was observed in 8. An intentional tumor tissue was left in an eloquent brain region (mean volume 7cc) in 13 patients. Bleeding and ischemia complications were detected early on ioMR in 5%. MRI length was 47 min on average., Conclusions: Intraoperative MRI was a useful and safe technique, and no associated complications were registered., (Copyright © 2021 Sociedad Española de Neurocirugía. Published by Elsevier España, S.L.U. All rights reserved.)

The emerging field of neuroprosthetics is focused on the development of new therapeutic interventions that will be able to restore some lost neural function by selective electrical stimulation or by harnessing activity recorded from populations of neurons. As more and more patients benefit from these approaches, the interest in neural interfaces has grown significantly and a new generation of penetrating microelectrode arrays are providing unprecedented access to the neurons of the central nervous system (CNS). These microelectrodes have active tip dimensions that are similar in size to neurons and because they penetrate the nervous system, they provide selective access to these cells (within a few microns). However, the very long-term viability of chronically implanted microelectrodes and the capability of recording the same spiking activity over long time periods still remain to be established and confirmed in human studies. Here we review the main responses to acute implantation of microelectrode arrays, and emphasize that it will become essential to control the neural tissue damage induced by these intracortical microelectrodes in order to achieve the high clinical potentials accompanying this technology.

Cerebral arteriovenous malformations (AVMs) are uncommon. Treatment options include embolization, radiosurgery and surgery, separately or combined, the final goal being complete occlusion of the malformation. We describe the case of a symptomatic small subependymal AVM with a single deep drainage vein previously treated unsuccessfully by radiosurgery and transarterial embolization. The AVM was successfully embolized transvenously using Onyx, achieving complete occlusion in a single treatment session.

Cerebral arteriovenous malformations (AVMs) are uncommon. Treatment options include embolization, radiosurgery and surgery, separately or combined, the final goal being complete occlusion of the malformation. We describe the case of a symptomatic small subependymal AVM with a single deep drainage vein previously treated unsuccessfully by radiosurgery and transarterial embolization. The AVM was successfully embolized transvenously using Onyx, achieving complete occlusion in a single treatment session.

Fibroblast growth factors (FGFs) are important for dopamine neurons in health and disease. Acidic (aFGF) and basic (bFGF) fibroblast growth factors increase the survival and growth of dopamine cells. Nigrostriatal dopamine neurons, the target cells for degeneration in Parkinson's disease, display receptors for basic fibroblast growth factor and these receptors are decreased in the brain of parkinsonian patients. We have investigated the effects of long-term intrastriatal infusion of FGFs in hemiparkinsonian monkeys. All animals were lesioned with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), 0.4mgkg(-1), into the left internal carotid artery. The monkeys that had persistent asymmetric akinesia and contralateral rotation induced by apomorphine, were selected for chronic, unilateral, intracerebral infusion of neurotrophic factors or vehicle into the striatum ipsilateral to the lesion. Two animals received intrastriatal aFGF or bFGF, 2mugweek(-1), for 6 months. The controls received intrastriatal saline or intraventricular epidermal growth factor (EGF). F-DOPA positron emission tomography scans were performed in each animal before and after the intracerebral infusion of neurotrophic factors. We measured the tyrosine hydroxylase (TH) immunoreactive neurons in the substantia nigra and terminals in the striatum and evaluated the pathological complications related to the treatment or the delivery system. All four animals had, after the lesion with MPTP, a transient but incomplete recovery of akinesia. This period of spontaneous improvement was followed by a progressive deterioration of motor behaviour during the following months. The monkeys treated with FGFs, however, recovered quickly and persistently during the intracerebral infusion. F-DOPA uptake, prior to the intracerebral infusion, was greatly reduced in the lesioned striatum. The post-infusion F-DOPA scans revealed a 60% reduction respect to baseline in the lesioned striatum of the saline and EGF-infused animals. In the animals infused with FGFs, the post-infusion F-DOPA uptake increased more than 400% in the lesioned (and infused) striatum and around 200-300% in the contralateral side, with respect to the pre-infusion scan. The number of TH-positive cells in the substantia nigra correlated well with the uptake of F-DOPA in the post-infusion scan. No severe side-effects were present. Intrastriatal infusion of FGFs restores motor behaviour and increases F-DOPA striatal uptake in hemiparkinsonian monkeys.