Navigated 3D-ultrasound versus conventional neuronavigation during awake resections of eloquent low-grade gliomas: a comparative study at a single institution.

BACKGROUND: The data showing usefulness of navigated 3D-ultrasound (3DUS) during awake resections of eloquent gliomas are sparse. Results of surgeries performed using 3DUS were never compared to procedures guided by standard neuronavigation. The aim of this work is to assess the effectiveness of 3DUS during awake resections of eloquent low-grade gliomas (LGGs) by comparing surgical results of two series of patients operated on using conventional neuronavigation and using 3DUS. To our knowledge, a similar study is lacking in the literature. METHODS: During a 4-year period (September 2006 to August 2010) 21 awake resections of LGGs guided by neuronavigation (series 1, S1) were consecutively performed in Department of Neurosurgery in Bratislava. During another 4-year period (August 2010 to July 2014) 28 awake resections of LGGs guided by 3DUS (series 2, S2) were consecutively conducted. In both patients series, the eloquent cortical and subcortical structures were intraoperatively detected by direct electrical stimulation. Extent of tumor resection (EOR) and functional outcome in both series were compared. RESULTS: EOR was significantly greater (p = 0.022) in S2 (median = 93.25%; mean = 86.79%), as compared to S1 (median 87.1%; mean = 75.85%). One permanent minor deficit in S1 and 2 minor deficits in S2 occurred, the difference was not significant (p = 0.999). CONCLUSIONS: Our work represents the first study comparing results of surgeries guided by 3DUS versus conventional navigation. The extent of awake resections of eloquent LGG guided by 3DUS was greater comparing to awake resections guided by standard neuronavigation; use of 3DUS had no impact on the number of new permanent deficits.

Late-onset jaw and teeth pain mimicking trigeminal neuralgia associated with chronic vagal nerve stimulation: case series and review of the literature.

BACKGROUND: Vagal nerve stimulation (VNS) for refractory epilepsy is well established. Trigeminal neuralgia itself is a common disease in adults, and thus, late-onset pain in the trigeminal region under VNS, which is extremely rare, may not be recognized as caused by VNS. CASE PRESENTATION: Two patients with drug-resistant symptomatic epilepsy treated with chronic VNS experienced stimulation-related pain in the lower and upper jaw and teeth on the side of stimulation. No evidence of local spread of the stimulation current was present. The pain started with a delay of years after device implantation and weeks after the last increase in the pacing parameters. At the time of onset, the pain was not recognized as VNS-related, leading to extensive examinations. The trigeminal neuralgia-like pain resolved after adjustment of the stimulation current intensity. In one of the patients, the pain disappeared within one to two days following every epileptic seizure. To our knowledge, this is the first case report of late-onset trigeminal pain under VNS revealing a direct link between epileptogenic and pain processes. CONCLUSION: A painless interval between the last change of the pacing parameters and trigeminal pain can lead to the erroneous interpretation that this is a typical trigeminal neuralgia. The lack of its recognition as a side effect of VNS can lead to unnecessary examinations and delayed adjustment of stimulation parameters. In patients with signs of late-onset trigeminal pain under VNS with normal electrode impedance and no evidence of local current spread, the replacement of the VNS lead does not seem to be beneficial. A review of the literature on VNS side effects including pain and device malfunctions was undertaken.

Long-term effect of rituximab in a case with late-onset Rasmussen´s encephalitis with anti-ganglioside IgGQ1b and anti-GAD antibodies positivity. Case Report.

Rasmussen's encephalitis is a rare autoimmune encephalitis usually involving one brain hemisphere, presenting with refractory epileptic seizures, and neurological and cognitive decline. Only 10% of cases start later in adolescence/adulthood. The only effective treatment for refractory seizures in childhood is hemispherectomy. For late-onset cases with mild neurological deficit the hemispherectomy is usually postponed because of its severe consequences. Immunotherapy shows some temporal effect for seizure control and slowing the brain atrophy, mainly in late onset Rasmussen's encephalitis. We report a patient with late onset Rasmussen´s encephalitis with anti-ganglioside IgGQ1b and anti-GAD antibodies positivity, who failed immunotherapy with cytostatics, immunoglobulins and steroids. Anti-ganglioside IgGQ1b antibodies are typically associated with a Miller-Fisher variant of Guillain-Barre syndrome and Bickerstaff's brainstem encephalitis. The association with Rasmussen´s encephalitis was not described before. Patient´s neurological deficit was mild and hemispherectomy was refused. The treatment with rituximab, an anti-CD20+ monoclonal antibody, led to 36-month control of seizures without any signs of progression of neurological deficit and MRI brain atrophy. Although the treatment is associated with long term B-cells depletion, patient doesn´t suffer from any clinically relevant infection. The biological treatment with monoclonal antibodies might be the way to stabilize patients with Rasmussen´s encephalitis, mainly late-onset, to prevent them from harmful and devastating hemispherectomy.

Visualization of lenticulostriate arteries during insular low-grade glioma surgeries by navigated 3D ultrasound power Doppler: technical note.

OBJECTIVE Resection of insular gliomas is challenging. In cases of intraoperative injury to the lenticulostriate arteries (LSAs), the usual result is a dense hemiplegia. LSAs are usually localized just behind the medial tumor border but they can also be encased by the tumor. Thus, exact localization of these perforators is important. However, intraoperative localization of LSAs using conventional neuronavigation can be difficult due to brain shift. In this paper, the authors present a novel method of intraoperative LSA visualization by navigated 3D ultrasound (3DUS) power Doppler. This technique enables almost real-time imaging of LSAs and evaluation of their shift during insular tumor resections. METHODS Six patients harboring insular Grade II gliomas were consecutively operated on at the Department of Neurosurgery in Bratislava using visualization of LSAs by navigated 3DUS power Doppler. In all cases, the 3DUS data were repeatedly updated to compensate for the brain shift and display the actual position of LSAs and residual tumor. RESULTS Successful visualization of LSAs was achieved in all cases. During all surgeries, the distance between the bottom of the resection cavity and LSAs could be accurately evaluated; in all tumors the resection approached the LSAs and only a minimal amount of tissue covering these perforators was intentionally left in place to avoid injury to them. CONCLUSIONS Visualization of LSAs by navigated 3DUS power Doppler is a useful tool that may help to prevent injury of LSAs during removal of insular low-grade gliomas. However, reliability of this method has to be carefully evaluated in further studies.

A Seeming Paradox: Ischemic Stroke in the Context of Idiopathic Thrombocytopenic Purpura.

Nowadays, we have a relatively sophisticated standard approach to a patient with acute ischemic stroke, including the sequence of diagnostic methods and treatment modalities. In practice, however, we are occasionally confronted with a patient whose medical history or comorbidities force us to make a decision without the support of guidelines. One such situation is the occurrence of acute ischemic stroke in a patient with known idiopathic thrombocytopenic purpura, where a tendency to use thrombolysis, anticoagulants, or antiplatelet agents collides with the fear of life-threatening bleeding. In this review, we try to outline current understanding of the pathophysiology of "paradoxical" ischemic events in this illness characterized by thrombocytopenia and to summarize clinical experience from case reports dealing with this topic, which could help us to rely on more than individual opinion seen through a purely "neurological" or "hematological" prism.

Direct electrical stimulation of the optic radiation in patients with covered eyes.

Direct electrical stimulation (DES) of the optic radiation (OR) during an awake tumor resection has been repeatedly reported. In all cases, visual function monitoring was performed in patients with open eyes which were looking at a picture. We report a new modification of the standard method, OR stimulation in patient with closed and covered eyes. To the best of our knowledge, this method was not presented before. According to our first experience, this methodology may be in some cases a potentially more sensitive form of neuromonitoring than the OR stimulation in patients with open eyes, as the phosphenes elicited by DES may be more distinct in patients with covered eyes. The technique is discussed, and a literature review on intraoperative identification of the OR is presented as well. However, a future prospective study is needed to confirm the relevance of our finding.

Subtemporal transtentorial resection of cavernous malformations involving the pyramidal tract in the upper pons and mesencephalon.

BACKGROUND: Lateral approaches to the brain stem for the resection of the cavernous malformations are preferred in order to avoid the structures within the floor of the fourth ventricle. The entry behind the pyramidal tract (PT) is usually carried out through the posterolateral surface of the brain stem. The more straightforward lateral approach below the temporal lobe is used rarely because of potential risks. METHODS: The outcome after resection of the cavernomas involving the PT in the mesencephalon and the upper pons via the subtemporal transtentorial approach in nine patients was analysed. Mapping of the PT by direct electrical stimulation was used in the last four patients. RESULTS: The subtemporal transtentorial approach enabled adequate exposure of the lateral and anterolateral surface of the midbrain and the upper pons. No adverse events from the elevation of the temporal lobe were encountered. Direct electrical stimulation using a bipolar electrode with the parameters of 100 Hz, 1 ms, and 3-9 mA evoked motor responses in three of four patients. It allowed placing the incision in the lateral surface of the midbrain behind the PT or between the fibres of the upper and the lower extremity. No worsening of the PT functions was observed in the series. CONCLUSIONS: The subtemporal transtentorial approach enables adequate exposure of the lateral and the anterolateral surface of the mesencephalon and upper pons, allowing neurophysiological mapping of the PT and thus avoiding its damage during removal of the cavernoma.