Search results for "Crania"
showing 10 items of 885 documents
Increased Neural Activity in Mesostriatal Regions after Prefrontal Transcranial Direct Current Stimulation and L-DOPA Administration
2019
Dopamine dysfunction is associated with a wide range of neuropsychiatric disorders commonly treated pharmacologically or invasively. Recent studies provide evidence for a nonpharmacological and noninvasive alternative that allows similar manipulation of the dopaminergic system: transcranial direct current stimulation (tDCS). In rodents, tDCS has been shown to increase neural activity in subcortical parts of the dopaminergic system, and recent studies in humans provide evidence that tDCS over prefrontal regions induces striatal dopamine release and affects reward-related behavior. Based on these findings, we used fMRI in healthy human participants and measured the fractional amplitude of low…
Reorganization of cortical motor area in prior polio patients
1999
Focal transcranial magnetic stimulation (TMS) was used to study the motor maps of upper limb muscles in 7 adult patients with a history of paralytic poliomyelitis. The aim of the study was to verify the potential for long-term cortical reorganization of a selective peripheral motor neuron lesion suffered early in life.Patient selection was based on the prevalent involvement of proximal muscles in only one of the upper limbs. Motor evoked potentials (MEPs) were recorded from deltoid and abductor pollicis brevis (APB) muscles. Each muscle map was characterized by area (no. of excitable positions), volume (the sum of MEP amplitudes at all scalp positions), maximal amplitude (the highest MEP re…
Endoscopic Neurosurgery and Endoscope-assisted Microneurosurgery for the Treatment of Intracranial Cysts
1998
Objective Different endoscopic techniques have been introduced into neurosurgery, but accepted terminology and definitions are still missing. We propose a terminology based on whether the endoscope is used alone or in conjunction with an operating microscope and on whether the route of surgical manipulations is through or outside the endoscope. Accordingly, procedures are categorized into endoscopic neurosurgery (EN), endoscope-assisted microneurosurgery (EAM), and endoscope-controlled microneurosurgery (ECM). Methods We treated 36 patients with intracranial arachnoid cysts (ACs) and intraventricular cysts endoscopically. The patients ranged in age from 4 months to 69 years (mean age, 31 yr…
Endoscope-assisted Brain Surgery: Part 2—Analysis of 380 Procedures
1998
Objectives Microsurgical techniques and instruments that help to reduce intraoperative retraction of normal intracranial neuronal and vascular structures contribute to improved postoperative results. To achieve sufficient control of the operating field without retraction of neurovascular components, the resection of dura and bone edges is frequently required, which, on the other hand, increases operating time and operation-related trauma. The use of endoscopes may help to reduce retraction and, at the same time, may help to avoid additional dura and bone resection. The aim of this study is to describe the principles on which the technique of endoscope-assisted brain surgery is based, to giv…
The influence of surgical experience on the rate of intraoperative aneurysm repture and its impact on aneurysm treatment outcome.
2001
Abstract BACKGROUND The influence of surgical experience on the result of aneurysm surgery remains unclear. To determine the impact of surgical experience we considered the occurrence of intraoperative aneurysm rupture (IAR) during microneurosurgery for intracranial aneurysms as an objective factor that could be evaluated. METHODS A retrospective study was performed on 379 consecutive patients with 490 cerebral aneurysms operated upon from 1989 to 1995. RESULTS IAR occurred in 6.7% of aneurysms and 8.7% of patients. There was a direct inverse relationship between the annual caseload of the surgeon and the risk of IAR. New neurological deficits (NND) occurred in 21% of patients with IAR, whi…
Development and external validation of a clinical prediction model for functional impairment after intracranial tumor surgery
2021
OBJECTIVE Decision-making for intracranial tumor surgery requires balancing the oncological benefit against the risk for resection-related impairment. Risk estimates are commonly based on subjective experience and generalized numbers from the literature, but even experienced surgeons overestimate functional outcome after surgery. Today, there is no reliable and objective way to preoperatively predict an individual patient’s risk of experiencing any functional impairment. METHODS The authors developed a prediction model for functional impairment at 3 to 6 months after microsurgical resection, defined as a decrease in Karnofsky Performance Status of ≥ 10 points. Two prospective registries in…
Vertebro-Basilar Junction Aneurysms: A Single Centre Experience and Meta-Analysis of Endovascular Treatments
2014
Vascular lesions of the vertebrobasilar junction (VBJ) are challenging in neurosurgical practice, and their gold-standard therapy is still under debate. We describe the operative strategies currently in use for the management of these complex vascular lesions and discuss their rationale in a literature meta-analysis and single centre blinded retrospective study. The single centre study included a review of initial presentation, angiographic features and clinical outcome (with modified Rankin Scale [mRS] scores) over a long-term follow-up. In our series, small aneurysms were effectively treated by endosaccular coil embolization, whereas a strategy including flow-diverter devices combined wi…
Optic nerve decompression in trauma and tumor patients
1999
Optic nerve decompression is a procedure that is now receiving increasing clinical attention. However, there are currently no standardized treatment protocols in the therapy of traumatic or pressure insults to the nerve. The present retrospective study was designed to report our experience with microscopic endonasal transethmoid-sphenoid optic nerve decompression in 24 unilateral trauma cases and 11 unilateral skull base tumor patients. In general preoperative visual acuities in the trauma patients were worse than in the tumor patients. Following surgery, 9 of 11 tumor patients (82%) had at least some improvement of their vision, including 5 complete recoveries. In the group with traumatic …
Lack of effects of low frequency repetitive transcranial magnetic stimulation on alpha rhythm phase synchronization in migraine patients
2010
The study aimed to test the modulation induced by 1 Hz repetitive Transcranial Magnetic Stimulation (rTMS) of the occipital cortex on the alpha phase synchronization under repetitive flash stimuli in 15 migraine without aura patients compared to 10 controls. The EEG was recorded by 7 channels, while flash stimuli were delivered at 9, 18, 21 and 24 Hz in basal, rTMS (15 min of 1 Hz stimulation of the occipital cortex) and sham conditions. Migraine patients displayed increased alpha-band phase synchronization under visual stimulation, while an overall desynchronizing effect was evident in controls. The rTMS resulted in a slight increase of synchronization index in migraine patients, which did…
Reduced Threshold for Inhibitory Homeostatic Responses in Migraine Motor Cortex? A tDCS/TMS Study
2014
Background and Objective Neurophysiological studies in migraine have reported conflicting findings of either cortical hyper- or hypoexcitability. In migraine with aura (MwA) patients, we recently documented an inhibitory response to suprathreshold, high-frequency repetitive transcranial magnetic stimulation (hf-rTMS) trains applied to the primary motor cortex, which is in contrast with the facilitatory response observed in the healthy subjects. The aim of the present study was to support the hypothesis that in migraine, because of a condition of basal increased cortical responsivity, inhibitory homeostatic-like mechanisms of cortical excitability could be induced by high magnitude stimulati…