Ultra-high magnetic resonance imaging (MRI): a potential examination for deep brain stimulation devices and the limitation study concerning MRI-related heating injury.

Nowadays, the patients with deep brain stimulation (DBS) devices are restricted to undertake 1.5T magnetic resonance imaging (MRI) according to the guideline. Nevertheless, we conducted an experiment to test pathological change near the leads in different field-strength MRI. Twenty-four male New Zealand rabbits were assigned to Group 1 (G1, n = 6, 7.0T, DBS), Group 2 (G2, n = 6, 3.0T, DBS), Group 3 (G3, n = 6, 1.5T, DBS), and Group 4 (G4, n = 6, 1.5T, paracentesis). DBS leads were implanted in G1, G2 and G3, targeting left nucleus ventralis posterior thalami. Paracentesis was performed in G4. 24 h after MRI scan, all animals were killed for examining pathological alternation (at different distance from lead) via transmission electron microscopy. Our results suggest that the severity of tissue injury correlates with the distance to electrode instead of field strength of MRI. Up to now, the reason for the restriction of MRI indicated no significantly different pathological change.

The ability of anterior thalamic signals to predict seizures in temporal lobe epilepsy in kainate-treated rats.

OBJECTIVE: To analyze the local field potential (LFP) of the anterior nucleus of the thalamus (ANT) of epileptic rats using the Generic Osorio-Frei algorithm (GOFA), and to determine the ability of the ANT LFP to predict clinical seizures in temporal lobe epilepsy. METHODS: GOFA is an advanced real-time technique used to detect and predict seizures. In this article, GOFA was utilized to process the electrical signals of ANT and the motor cortex recorded in 12 rat models of temporal lobe epilepsy (TLE) induced via the injection of kainic acid into the unilateral hippocampus. The electroencephalography (EEG) data included (1) 161 clinical seizures (each contained a 10-min segment) involving the ANT and cortical regions and (2) one hundred three 10-min segments of randomly selected interictal (no seizure) data. RESULTS: Minimal false-positives (0.51 ± 0.36/h) and no false-negatives were detected based on the ANT LFP data processed using GOFA. In ANT LFP, the delay from electrographic onset (EO) to automated onset (AO) was 1.24 ± 0.47 s, and the delay from AO to clinical onset (CO) was 7.73 ± 3.23 s. The AO time occurred significantly earlier in the ANT than in the cortex (p = 0.001). In 75.2% of the clinical onsets predicted by ANT LFP, it was 1.37 ± 0.82 s ahead of the prediction of cortical potentials (CPs), and the remainder were 0.84 ± 0.31 s slower than the prediction of CPs. SIGNIFICANCE: ANT LFP appears to be an optimal option for the prediction of seizures in temporal lobe epilepsy. It was possible to upgrade the responsive neurostimulation system to emit electrical stimulation in response to the prediction of epileptic seizures based on the changes in the ANT LFP.

Subthalamic deep brain stimulation with a new device in Parkinson's disease: an open-label trial.

OBJECTIVE: We aimed to evaluate the safety and efficacy of subthalamic nucleus deep brain stimulation (STN-DBS) with a new stimulator (Beijing PINS Medical Co., Ltd, PNS 1101) in Parkinson's disease (PD). MATERIALS AND METHODS: Forty patients received a PINS device implantation in the subthalamic nucleus. The effects of stimulation on motor score, activities of daily living, good-quality on-time, and the levodopa-equivalent dose were analyzed for all 40 patients with PD treated with bilateral or unilateral STN-DBS. The scores were collected at baseline in two conditions (on/off medication) and at 3, 6, 9, 12, and 24 months of follow-up with stimulation in the absence or presence of medication. The patients were followed up for two years. RESULTS: At 3, 6, 9, 12, and 24 months of follow-up, our results showed a significant increase from baseline in both activities of daily living and motor scores (p < 0.001) and good-quality on-time (p < 0.001); the daily levodopa-equivalent dose decreased compared with baseline (p < 0.01). No patient died during the study, and none of the adverse effects were classified as severe. All of the adverse events were resolved or improved by the end of the study. CONCLUSIONS: STN-DBS with the PINS device significantly improved the symptoms of PD when compared with baseline in this trial. This new device may be recommended for the treatment of patients with advanced PD; however, a randomized, double-blinding trial will be required.

[Surgical techniques and efficacies of deep brain stimulation in the treatment of essential tremor].

OBJECTIVE: To explore the surgical techniques and efficacies of deep brain stimulation (DBS) in the treatment of the patients with essential tremor (ET). METHODS: A total of 6 ET patients from January 2004 to June 2011 at Department of Neurosurgery, Beijing Tiantan Hospital were recruited to receive DBS at ventral intermediate nucleus of thalamus (Vim-DBS) (n = 5) and subthalamic nucleus (STN-DBS) (n = 1). All underwent stereotactically guided DBS procedures utilizing atlas of neuroanatomy and neurophysiology, pre-operative magnetic resonance imaging (MRI), microelectrode recording and intra-operative testing for target-locating. Postoperative computed tomography (CT) and/or MRI scan were performed after implantation. Such stimulation parameters as stimulus voltage, frequency, pulse width and polarity configuration were adjusted postoperatively to optimize tremor control and maximize battery life. The patients were followed by further consultations or telephone for a comprehensive evaluation of their therapeutic efficacies. RESULTS: All patients showed typical electrical signal and relief of tremor symptoms with significant tremor control. No severe adverse events, such as infection, hemorrhage, paresthesia, dysarthria, cognitive deficits, imbalance and diplopia, appeared after the implantation of DBS electrodes. CONCLUSION: Vim-DBS and STN-DBS are both safe and effective for the controls of unilateral and bilateral tremors.

[Changes of glutamate and γ-aminobutyric acid of extracellular fluid in hippocampus during electrical stimulation of anterior nucleus thalamus in rats].

OBJECTIVE: To explore the changes of extracellular glutamate (Glu) and γ-aminobutyric acid (GABA) in hippocampus during the high-frequency stimulation of anterior nucleus thalamus (ANT) in epileptic rats. METHODS: A total of 30 rats were divided equally into 2 groups:epilepsy model and normal control (n = 15 each). Concentric bipolar electrodes were stereotaxically implanted in bilateral ANT. A high-frequency stimulation of 130 Hz was applied in the epilepsy group. Microdialysis probes were unilaterally lowered into hippocampus. The concentrations of Glu and GABA in dialysate samples were determined by high-performance liquid chromatography (HPLC). RESULTS: Electrical stimulation of ANT induced an increase of GABA and a decrease of Glu in hippocampus. CONCLUSION: An increase of GABA and a decrease of Glu during the electrical stimulation of ANT play an important role in the therapy of epilepsy.

Application of the robot-assisted implantation in deep brain stimulation.

Introduction: This work aims to assess the accuracy of robotic assistance guided by a videometric tracker in deep brain stimulation (DBS). Methods: We retrospectively reviewed a total of 30 DBS electrode implantations, assisted by the Remebot robotic system, with a novel frameless videometric registration workflow. Then we selected 30 PD patients who used stereotactic frame surgery to implant electrodes during the same period. For each electrode, accuracy was assessed using radial and axial error. Results: The average radial error of the robot-assisted electrode implantation was 1.28 ± 0.36 mm, and the average axial error was 1.20 ± 0.40 mm. No deaths or associated hemorrhages, infections or poor incision healing occurred. Conclusion: Robot-assisted implantation guided by a videometric tracker is accurate and safe.

Synchronized Intracranial Electrical Activity and Gait Recording in Parkinson's Disease Patients With Freezing of Gait.

Background: This study aimed to describe a synchronized intracranial electroencephalogram (EEG) recording and motion capture system, which was designed to explore the neural dynamics during walking of Parkinson's disease (PD) patients with freezing of gait (FOG). Preliminary analysis was performed to test the reliability of this system. Methods: A total of 8 patients were enrolled in the study. All patients underwent bilateral STN-DBS surgery and were implanted with a right subdural electrode covering premotor and motor area. Synchronized electrophysiological and gait data were collected using the Nihon Kohden EEG amplifier and Codamotion system when subjects performed the Timed Up and Go (TUG) test. To verify the reliability of the acquisition system and data quality, we calculated and compared the FOG index between freezing and non-freezing periods during walking. For electrophysiological data, we first manually reviewed the scaled (five levels) quality during waking. Spectra comprising broadband electrocorticography (ECoG) and local field potential (LFP) were also compared between the FOG and non-FOG states. Lastly, connectivity analysis using coherence between cortical and STN electrodes were conducted. In addition, we also use machine learning approaches to classified FOG and non-FOG. Results: A total of 8 patients completed 41 walking tests, 30 of which had frozen episodes, and 21 of the 30 raw data were level 1 or 2 in quality (70%). The mean ± SD walking time for the TUG test was 85.94 ± 47.68 s (range: 38 to 190.14 s); the mean ± SD freezing duration was 12.25 ± 7.35 s (range: 1.71 to 27.50 s). The FOG index significantly increased during the manually labeled FOG period (P < 0.05). The beta power of STN LFP in the FOG period was significantly higher than that in the non-FOG period (P < 0.05), while the band power of ECoG did not exhibit a significant difference between walking states. The coherence between the ECoG and STN LFP was significantly greater in high beta and gamma bands during the FOG period compared with the shuffled surrogates (P < 0.05). Lastly, STN-LFP band power features showed above-chance performance (p < 0.01, permutation test) in identifying FOG epochs. Conclusion: In this study, we established and verified the synchronized ECoG/LFP and gait recording system in PD patients with FOG. Further neural substrates underlying FOG could be explored using the current system.

Bilateral subthalamic nucleus stimulation in the treatment of neurodegeneration with brain iron accumulation type 1.

BACKGROUND: Neurodegeneration with brain iron accumulation type 1 (NBIA1), previously called Hallervorden-Spatz disease, is a rare neurodegenerative condition with abnormal brain iron accumulation. There have been some reports of deep brain stimulation (DBS) in the treatment of NBIA1. However, the target was usually the globus pallidus internus or thalamus. OBJECTIVES/METHODS: We present a case of NBIA1 in a 16-year-old male who was treated with bilateral subthalamic nucleus (STN)-DBS and explored its efficacy in the treatment of NBIA1. The patient presented with severe generalized dystonia and marked dysarthria and had previously had unsuccessful ablation surgery. MRI confirmed the diagnosis of NBIA1. RESULTS: He had significant improvement postoperatively, and the benefit of surgery was maintained for 3 years during follow-up. Burke-Fahn-Marsden Dystonia Rating Scale score was 114/120 preoperatively, and dropped to 60/120 at 14 days, 35/120 at 1 month, 28/120 at 3 months, 14/120 at 1 year and 18/120 at 3 years postoperatively. CONCLUSIONS: Our results suggest that bilateral STN-DBS might be considered as an effective treatment for selective NBIA1 patients.

[Application of intracranial electrode for locating epileptogenic zone for temporal lobe epilepsy surgery].

OBJECTIVE: To explore the application of intracranial electrodes (IE) for temporal lobe epilepsy (TLE) surgery and assess the clinical utility of intracranial video electroencephalography (IVEEG). METHODS: The clinical data of 60 TLE patients undergoing implantation of IE were reviewed retrospectively. Cortical subdural strip, grids and depth electrodes were implanted by sphenotresia, bone disc craniotomy or stereotactic technology. RESULTS: The implanted electrodes were as follows: frontal-temporal lobe cortical strip (n = 34), frontal-anterior temporal-occipitotemporal lobe cortical strip (n = 7), bilateral temporal lobe cortical strip (n = 7), combined temporal lobe strip & depth (n = 7), anterior temporal-occipitotemporal junction cortical strip (n = 3) and combined strip & grid (n = 2). The following procedures were performed: anterior temporal lobectomy (ATL) (n = 50), combined ATL & frontal focal cortical resection (n = 7), combined ATL & callosotomy (n = 1) and combined neocortex epileptogenic focus resection & amygdalohippocampectomy (n = 2). CONCLUSION: IVEEG is effective and important for the localization of epileptogenic focus in patients with intractable temporal lobe epilepsy.

The Clinical Application of Robot-Assisted Ventriculoperitoneal Shunting in the Treatment of Hydrocephalus.

BACKGROUND: This work aims to assess the effectiveness and safety of robotic assistance in ventriculoperitoneal shunting and to compare the results with data from traditional surgery. METHODS: We retrospectively analyzed 60 patients who had undergone ventriculoperitoneal shunting, of which shunts were implanted using a robot in 20 patients and using traditional surgical methods in the other 40 patients. Data related to surgery were compared between the two groups, and the accuracy of the drainage tube in the robot-assisted group was assessed. RESULTS: In the robot-assisted surgery group, the operation duration was 29.75 ± 6.38 min, intraoperative blood loss was 10.0 ± 3.98 ml, the success rate of a single puncture was 100%, and the bone hole diameter was 4.0 ± 0.3 mm. On the other hand, the operation duration was 48.63 ± 6.60 min, intraoperative blood loss was 22.25 ± 4.52 ml, the success rate of a single puncture was 77.5%, and the bone hole diameter was 11.0 ± 0.2 mm in the traditional surgery group. The above are statistically different between the two groups (P < 0.05). Only one case of surgery-related complications occurred in the robot-assisted group, while 13 cases occurred in the traditional surgery group. There was no significant difference in the hospitalization time. In the robot-assisted surgery group, the average radial error was 2.4 ± 1.5 mm and the average axial error was 1.9 ± 2.1 mm. CONCLUSION: In summary, robot-assisted implantation is accurate, simple to operate, and practical; the duration of surgery is short; trauma to the patient is reduced; and fewer postoperative complications related to surgery are reported.

Clinical Application of a Neurosurgical Robot in Intracranial Ommaya Reservoir Implantation.

Background: The Ommaya reservoir implantation technique allows for bypass of the blood-brain barrier. It can be continuously administered locally and be used to repeatedly flush the intracranial cavity to achieve the purpose of treatment. Accurate, fast, and minimally invasive placement of the drainage tube is essential during the Ommaya reservoir implantation technique, which can be achieved with the assistance of robots. Methods: We retrospectively analyzed a total of 100 patients undergoing Ommaya reservoir implantation, of which 50 were implanted using a robot, and the remaining 50 were implanted using conventional surgical methods. We then compared the data related to surgery between the two groups and calculated the accuracy of the drainage tube of the robot-assisted group. Results: The average operation time of robot-assisted surgery groups was 41.17 ± 11.09 min, the bone hole diameter was 4.1 ± 0.5 mm, the intraoperative blood loss was 11.1 ± 3.08 ml, and the average hospitalization time was 3.9 ± 1.2 days. All of the Ommaya reservoirs were successful in one pass, and there were no complications such as infection or incorrect placement of the tube. In the conventional Ommaya reservoir implantation group, the average operation time was 65 ± 14.32 min, the bone hole diameter was 11.3 ± 0.3 mm, the intraoperative blood loss was 19.9 ± 3.98 ml, and the average hospitalization time was 4.1 ± 0.5 days. In the robot-assisted surgery group, the radial error was 2.14 ± 0.99 mm and the axial error was 1.69 ± 1.24 mm. Conclusions: Robot-assisted stereotactic Ommaya reservoir implantation is quick, effective, and minimally invasive. The technique effectively negates the inefficiencies of craniotomy and provides a novel treatment for intracranial lesions.

A Bulk Retrospective Study of Robot-Assisted Stereotactic Biopsies of Intracranial Lesions Guided by Videometric Tracker.

Background: Biopsies play an important role in the diagnosis of intracranial lesions, and robot-assisted procedures are increasingly common in neurosurgery centers. This research investigates the diagnoses, complications, and technology yield of 700 robotic frameless intracranial stereotactic biopsies conducted with the Remebot system. Method: This research considered 700 robotic biopsies performed between 2016 and 2020 by surgeons from the Department of Functional Neurosurgery in Beijing's Tiantan Hospital. The data collected included histological diagnoses, postoperative complications, operation times, and the accuracy of robotic manipulation. Results: Among the 700 surgeries, the positive rate of the biopsies was 98.2%. The most common histological diagnoses were gliomas, which accounted for 62.7% of cases (439/700), followed by lymphoma and germinoma, which accounted for 18.7% (131/700) and 7.6% (53/700). Bleeding was found in 14 patients (2%) by post-operation computed tomography scans. A total of 29 (4.14%) patients had clinical impairments after the operation, and 9 (1.29%) experienced epilepsy during the operation. The post-biopsy mortality rate was 0.43%. Operation time-from marking the cranial point to suturing the skin-was 16.78 ± 3.31 min (range 12-26 min). The target error was 1.13 ± 0.30 mm, and the entry point error was 0.99 ± 0.24 mm. Conclusion: A robot-assisted frameless intracranial stereotactic biopsy guided by a videometric tracker is an efficient, safe, and accurate method for biopsies.

Stimulation of Anterior Thalamic Nuclei Protects Against Seizures and Neuronal Apoptosis in Hippocampal CA3 Region of Kainic Acid-induced Epileptic Rats.

BACKGROUND: The antiepileptic effect of the anterior thalamic nuclei (ANT) stimulation has been demonstrated; however, its underlying mechanism remains unclear. The aim of this study was to investigate the effect of chronic ANT stimulation on hippocampal neuron loss and apoptosis. METHODS: Sixty-four rats were divided into four groups: The control group, the kainic acid (KA) group, the sham-deep brain stimulation (DBS) group, and the DBS group. KA was used to induce epilepsy. Seizure count and latency to the first spontaneous seizures were calculated. Nissl staining was used to analyze hippocampal neuronal loss. Polymerase chain reaction and Western blotting were conducted to assess the expression of caspase-3 (Casp3), B-cell lymphoma-2 (Bcl2), and Bcl2-associated X protein (Bax) in the hippocampal CA3 region. One-way analysis of variance was used to determine the differences between the four groups. RESULTS: The latency to the first spontaneous seizures in the DBS group was significantly longer than that in the KA group (27.50 ± 8.05 vs. 16.38 ± 7.25 days, P = 0.0005). The total seizure number in the DBS group was also significantly reduced (DBS vs. KA group: 11.75 ± 6.80 vs. 23.25 ± 7.72, P = 0.0002). Chronic ANT-DBS reduced neuronal loss in the hippocampal CA3 region (DBS vs. KA group: 23.58 ± 6.34 vs. 13.13 ± 4.00, P = 0.0012). After chronic DBS, the relative mRNA expression level of Casp3 was decreased (DBS vs. KA group: 1.18 ± 0.37 vs. 2.09 ± 0.46, P = 0.0003), and the relative mRNA expression level of Bcl2 was increased (DBS vs. KA group: 0.92 ± 0.21 vs. 0.48 ± 0.16, P = 0.0004). The protein expression levels of CASP3 (DBS vs. KA group: 1.25 ± 0.26 vs. 2.49 ± 0.38, P < 0.0001) and BAX (DBS vs. KA group: 1.57 ± 0.49 vs. 2.80 ± 0.63, P = 0.0012) both declined in the DBS group whereas the protein expression level of BCL2 (DBS vs. KA group: 0.78 ± 0.32 vs. 0.36 ± 0.17, P = 0.0086) increased in the DBS group. CONCLUSIONS: This study demonstrated that chronic ANT stimulation could exert a neuroprotective effect on hippocampal neurons. This neuroprotective effect is likely to be mediated by the inhibition of apoptosis in the epileptic hippocampus.

Deep brain stimulation of the subthalamic and pedunculopontine nucleus in a patient with Parkinson's disease.

Deep brain stimulation (DBS) of the pedunculopontine nucleus (PPN) is a novel therapy developed to treat Parkinson's disease. We report a patient who underwent bilateral DBS of the PPN and subthalamic nucleus (STN). He suffered from freezing of gait (FOG), bradykinesia, rigidity and mild tremors. The patient underwent bilateral DBS of the PPN and STN. We compared the benefits of PPN-DBS and STN-DBS using motor and gait subscores. The PPN-DBS provided modest improvements in the gait disorder and freezing episodes, while the STN-DBS failed to improve the dominant problems. This special case suggests that PPN-DBS may have a unique role in ameliorating the locomotor symptoms and has the potential to provide improvement in FOG.

Favorable modulation in neurotransmitters: effects of chronic anterior thalamic nuclei stimulation observed in epileptic monkeys.

Anterior thalamic nuclei (ATN) stimulation has been shown to be effective in seizure reduction. Nevertheless, the underlying mechanisms remain unclear. This study investigated the changes in the amino acid levels during chronic, single-sided ATN-stimulation in the hippocampi of rhesus monkeys with mesial temporal lobe epilepsy induced by kainic acid (KA). The concentrations of glutamate, γ-aminobutyric acid, aspartate and taurine in the dialysates from bilateral hippocampi were determined at multiple time points using high-performance liquid chromatography. The results showed that after KA administration, the aspartate, γ-aminobutyric acid and taurine levels increased significantly in the sham-stimulation group, although the γ-aminobutyric acid and taurine levels gradually returned to the basal levels in the chronic stage. The glutamate level showed an initial decrease in the acute stage and a subsequent increase in the chronic stage. Chronic ATN-stimulation reversed the increases in the glutamate and aspartate levels, and maintained the initial increases in the γ-aminobutyric acid and taurine levels till the end of the experiment. These amino acid levels, however, were not affected by either contralateral KA injection or contralateral ATN-stimulation, suggesting that the observed effects of ATN-stimulation are restricted to the ipsilateral hemisphere. Our data suggest that chronic ATN-stimulation may induce favorable modulations in the amino acid levels in the hippocampi of epileptic monkeys, which may be an important mechanism underlying the effects of ATN-stimulation in epilepsy treatment.

Potential Protective Effects of Chronic Anterior Thalamic Nucleus Stimulation on Hippocampal Neurons in Epileptic Monkeys.

BACKGROUND: Stimulation of the anterior nucleus of the thalamus (ANT) is effective in seizure reduction, but the mechanisms underlying the beneficial effects of ANT stimulation are unclear. OBJECTIVE: To assess the beneficial effects of ANT stimulation on hippocampal neurons of epileptic monkeys. METHODS: Chronic ANT stimulation was applied to kainic acid-induced epileptic monkeys. Behavioral seizures were continuously monitored. Immunohistochemical staining and western blot assays were performed to assess the hippocampal injury and the effects of ANT stimulation. RESULTS: The frequency of seizures was 42.8% lower in the stimulation group compared with the sham-stimulation group. Immunohistochemical staining and western blot analyses indicated that neuronal loss and apoptosis were less severe and that neurofilament synthesis was enhanced in the stimulation monkeys compared with the sham-stimulation group. These data showed that the hippocampal injury was less severe in monkeys in the stimulation group than in those in the sham-stimulation group. CONCLUSIONS: Our data suggest that chronic ANT stimulation may exert protective effects on hippocampal neurons and boost the regeneration of neuronal fibers. These effects may be closely related to the mechanisms of ANT stimulation in epilepsy treatment.

Pathological alterations and stress responses near DBS electrodes after MRI scans at 7.0T, 3.0T and 1.5T: an in vivo comparative study.

OBJECTIVE: The purpose of this study was to investigate the pathological alterations and the stress responses around deep brain stimulation (DBS) electrodes after magnetic resonance imaging (MRI) scans at 7.0T, 3.0T and 1.5T. MATERIALS AND METHODS: DBS devices were stereotactically implanted into the brains of New Zealand rabbits, targeting the left nucleus ventralis posterior thalami, while on the right side, a puncture passage pointing to the same target was made. MRI scans at 7.0T, 3.0T and 1.5T were performed using transmit/receive head coils. The pathological alterations of the surrounding tissue were evaluated by hematoxylin and eosin staining (H&E staining) and transmission electron microscopy (TEM). The levels of the 70 kDa heat shock protein (HSP-70), Neuronal Nuclei (NeuN) and Caspase-3 were determined by western-blotting and quantitative polymerase chain reaction (QPCR) to assess the stress responses near the DBS electrodes. RESULTS: H&E staining and TEM showed that the injury around the DBS electrodes was featured by a central puncture passage with gradually weakened injurious alterations. Comparisons of the injury across the groups manifested similar pathological alterations near the DBS electrodes in each group. Moreover, western-blotting and QPCR assay showed that the level of HSP-70 was not elevated by MRI scans (p>0.05), and the levels of NeuN and Caspase-3 were equal in each group, regardless of the field strengths applied (p>0.05). CONCLUSIONS: Based on these findings, it is reasonable to conclude that in this study the MRI scans at multiple levels failed to induce additional tissue injury around the DBS electrodes. These preliminary data furthered our understanding of MRI-related DBS heating and encouraged revisions of the current MRI guidelines for patients with DBS devices.

A rat model of hemidystonia induced by 3-nitropropionic acid.

OBJECTIVE: Secondary dystonia commonly presents as hemidystonia and is often refractory to current treatments. We aimed to establish an inducible rat model of hemidystonia utilizing 3-nitropropionic acid (3-NP) and to determine the pathophysiology of this model. METHODS: Two different doses of 3-NP were stereotactically administered into the ipsilateral caudate putamen (CPu) of Wistar rats. Behavioral changes and alterations in the neurotransmitter levels in the basal ganglia were analyzed. We also performed an electromyogram, 7.0-T magnetic resonance imaging and transmission electron microscopy examination to determine the pathophysiology of the model. RESULTS: In the CPu region, 3-NP produced mitochondrial cristae rupture, axonal degeneration, increased excitatory synaptic vesicles and necrosis. The extracellular concentrations of excitatory amino acids increased, whereas the inhibitory amino acids decreased in the CPu. Furthermore, an imbalance of neurotransmitters was found in other regions of the basal ganglia with the exception of the external globus pallidus. This study demonstrated that 3-NP administration results in CPu damage, and combined with a neurotransmitter imbalance in the basal ganglia, it produces specific neurobehavioral changes in rats. Right limb (contralateral side of CPu lesion) and trunk dystonic postures, shortened step length and ipsiversive dystonic posturing were observed in these rats. Furthermore, EMG recordings confirmed that co-contraction of the agonist and antagonist muscles could be seen for several seconds in right limbs. CONCLUSIONS: Stereotactic injection of 3-NP into the ipsilateral CPu of rats established an inducible model for hemidystonia. This effect might result from an imbalance of neurotransmitter levels, which induce dysfunctional activity of the basal ganglia mainly via the cortico-striato-GPi direct pathway. Symptoms in this model were present for 1 week. Activation of the cortico-striato-GPe indirect pathway and rebalance of neurotransmitters may lead to recovery. This rat model may be a suitable tool used to understand and further investigate the pathophysiology of dystonia.

Hemangiopericytomas in the spine: clinical features, classification, treatment, and long-term follow-up in 26 patients.

BACKGROUND: Intraspinal hemangiopericytoma (HPC) is a rare and malignant extra-axial tumor with a strong tendency to recur and metastasize. There is a paucity in the literature of large case series of patients with intraspinal HPCs. OBJECTIVE: We retrospectively analyzed the clinical radiological and histological features, classification, and treatment of 26 patients with HPCs in the spine. METHODS: Twenty-six patients with HPCs in the spine were treated at our institution between 1987 and 2010. Medical records were reviewed retrospectively to collect data on the clinical features, tumor morphology, surgical resection, recurrence, and follow-up. RESULTS: The 26 patients were predominantly male, and the mean age at diagnosis was 33.8 years. The intraspinal HPCs were divided into 3 types and 5 subtypes. Most of them involved the neighboring segments and/or caused bony erosion. All tumors were immunohistochemically positive for vimentin and negative for epithelial membrane antigen. All patients underwent at least 1 surgery, and most of them received postsurgical radiotherapy. The 5-year Kaplan-Meier rate of survival was 76%. The 5-year recurrence-free rate of survival was 29.4%. Only the tumor pathological grade was significantly associated with survival time and recurrence. CONCLUSION: High-grade tumors had a shorter survival time and recurred earlier than low-grade tumors. Surgical removal and postoperative radiotherapy are critical for the treatment of intraspinal HPCs. However, total resection may not necessary for these tumors. Stereotactic radiosurgery may be a good alternative to control the recurrent lesions.

Effect of anterior nucleus of thalamus stimulation on glucose metabolism in hippocampus of epileptic rats.

BACKGROUND: Electrical stimulation of the anterior nucleus of the thalamus (ANT) appears to be effective against seizures. In this study, we investigated changes in glucose metabolism during high-frequency stimulation of ANT in epileptic rats. METHODS: Three groups of rats were used: (1) a stimulation group (n = 12), (2) a sham stimulation group (n = 12) with seizures induced by stereotactic administration of kainic acid (KA), and (3) a control group (n = 12) with sham surgery. Concentric bipolar electrodes were stereotaxically implanted unilaterally in the ANT. High-frequency stimulation was performed in each group except the sham stimulation group. Microdialysis probes were lowered into the CA3 region of the hippocampus unilaterally but bilaterally in the stimulation group. The concentrations of glucose, lactate, and pyruvate in dialysate samples were determined by an ISCUS microdialysis analyzer. RESULTS: The extracellular concentrations of lactate and lactate/pyruvate ratio (LPR) of epileptic rats were significantly higher than in control rats (P = 0.020, P = 0.001; respectively). However, no significant difference in the concentration of glucose and pyruvate was found between these groups (P > 0.05). Electrical stimulation of ANT induced decreases in lactate and LPR in the ipsilateral hippocampus (KA injected) of the stimulation group (P < 0.05), but it did not influence the glucose metabolism in the contralateral hippocampus (P > 0.05). CONCLUSIONS: This study demonstrated that the glycolysis was inhibited in the ipsilateral hippocampus of epileptic rats during electrical ANT stimulation. These findings may provide useful information for better understanding the mechanism of ANT-deep brain stimulation.