Contralateral Interhemispheric Transfalcine Approach to the Basal Ganglia.

The contralateral interhemispheric approach provides a robust path into the mesial frontal lobe and basal ganglia structures.1 The use of gravity to retract the dominant frontal lobe allows the surgeon to avoid injury caused by exposure of the dominant hemisphere. The transfalcine corridor, however, is long and often not well illuminated, necessitating the use of lighted instruments. Within the path of approach lie the anterior cerebral arteries, which must be carefully dissected and preserved. Upon opening the falx, the entire mesial frontal lobe and deep basal ganglia structures can be readily accessed. Herein, we present a patient with familial cerebral cavernous malformation-1 syndrome who presented after an acute hemorrhage from a deep basal ganglia cerebral cavernous malformation (Video 1). The patient consented to the procedure. The patient was hemiparetic and aphasic, likely secondary to mass effect from the bleed. The lesion was approached from a contralateral interhemispheric approach and removed completely. The patient's examination improved with removal of the mass lesion. This case demonstrates the utility of this approach for accessing deep corridors within the cerebral cortices.

The Application Effect of Craniotomy through Transsylvian Rolandic Point-Insular Approach on Hypertensive Intracerebral Hemorrhage in Posterior Basal Ganglia.

Objective: To evaluate the hematoma clearance and safety of small bone window craniotomy through the lateral fissure Rolandic point-insular lobe approach for patients with hypertensive intracerebral hemorrhage (HICH) in posterior basal ganglia. Methods: This retrospective study enrolled a total of 86 patients with HICH in the posterior basal ganglia region who underwent surgery between January 2020 and December 2021. These patients were divided into two groups: the conventional group and the study group. The intraoperative information, postoperative hematoma clearance rate, increasing rate of cerebral edema and rebleeding occurrence rate, postoperative complication rate, and prognoses were compared between the two groups. Additionally, we observed and compared the rate of postoperative cerebral hematoma increase, as well as the neurological function and activities of daily living (ADL) at admission, 3 months, and 6 months after surgery in both groups. Univariate and multivariate logistic regression analyses were performed to explore factors affecting the prognosis of patients with HICH in the posterior basal ganglia region after small bone window craniotomy through the lateral fissure Rolandic point-insular lobe approach. Results: The study group exhibited significantly shorter automatic eye-opening times and hospital stays compared to the conventional group (P < 0.05). Furthermore, the study group demonstrated better hematoma clearance rates, lower rates of cerebral hematoma at postoperative 48 h and 72 h, and lower rates of rebleeding compared to the conventional group (P < 0.05). At 3 and 6 months postsurgery, the study group exhibited a significantly greater improvement in neurological function and ADL compared to the conventional group (P < 0.05). Additionally, the incidence of postoperative complications in the study group was lower than that in the conventional group (P < 0.05). Furthermore, the prognosis of the study group was significantly better than that of the conventional group at the 6-month follow-up (P < 0.05). Conclusion: A small bone window craniotomy via transsylvian Rolandic point-insular approach has been shown to improve the hematoma clearance rate in patients with HICH in the posterior basal ganglia region while also reducing the incidence of complications. This approach is highly safe and feasible for implementation in clinical practice.

Comparison of endoscopic evacuation, craniotomy, and puncture aspiration for the treatment of spontaneous basal ganglia intracerebral hematoma.

OBJECTIVE: To compare the prognosis of patients with spontaneous basal ganglia intracerebral hematoma treated by endoscopic evacuation, craniotomy, or puncture aspiration. METHODS: This retrospective observational study included information from patients with basal ganglia hematoma who received craniotomy, endoscopic evacuation, or puncture aspiration in the Department of Neurosurgery of the First Affiliated Hospital of USTC between January 2016 and May 2021. Patients were grouped according to their treatment method for comparison. RESULTS: From a total of 184 patients, 62 cases (51 males, aged 54.44 ± 9.92 years) received craniotomy, 64 cases (45 males, aged 53.97 ± 11.87 years) received endoscopic evacuation, and 58 cases (43 males, aged 54.25 ± 10.35 years) received puncture aspiration. No significant difference was found in baseline characteristics among three surgical procedures. Patients in the endoscopy group had the shortest hospital stay (15.16 ± 4.89 days vs. 17.88 ± 5.97 and 20.77 ± 6.96 days), lowest infectious meningitis [1(1.6 %) vs. 2(3.4%) and 8(12.9%)] and pulmonary infection [3(4.7%) vs. 5(8.6%) and 13(21.0%)] rates, and highest hematoma removal rate (90.39 ± 5.22% vs. 35.87 ± 6.23 and 84.76 ± 4.91%) and Glasgow outcome scale 6 months after surgery (4.41 ± 0.53 vs. 3.74 ± 1.09 and 3.81 ± 1.03). The occurrence of gastrointestinal bleeding, epilepsy, and mortality were similar (all p > 0.05) among the groups. CONCLUSION: Patients with spontaneous basal ganglia intracerebral hematoma who received endoscopic evacuation might have better prognosis than those treated with craniotomy or puncture aspiration. In future, endoscopic surgery could become the most common method for treating spontaneous basal ganglia hemorrhages.

Comparison of the Efficacy of Subosseous Window Neuro-Endoscopy and Minimally Invasive Craniotomy in the Treatment of Basal Ganglia Hypertensive Intracerebral Hemorrhage.

OBJECTIVE: To compare the perioperative indexes and long-term effects of craniotomy and neuro-endoscopic hematoma removal in patients with hypertensive intracerebral hemorrhage (HICH) in the basal ganglia region. METHODS: This study involved 128 patients with HICH in the basal ganglia region who were admitted to our hospital from February 2020 to June 2022. They were divided into 2 groups according to the random number table method. The craniotomy group (n = 70) underwent microsurgery with small bone window craniotomy with a side cleft, and the neuro-endoscopy group (n = 58) underwent small bone window neuro-endoscopic surgery. A 3-dimensional Slicer was used to calculate the hematoma volume and clearance rate and the postoperative brain tissue edema volume. The operation time, intraoperative blood loss, postoperative intracranial pressure, complications, mortality, and improvement in the modified Rankin scale score at 6 months postoperatively were compared between the two groups. RESULTS: The clearance rate was significantly higher in the neuro-endoscopy group than in the craniotomy group (94.16% ± 1.86% versus 90.87% ± 1.89%, P < 0.0001). The operation time was significantly lower in the neuro-endoscopy group than in the craniotomy group (89.9 ± 11.7 versus 203.7 ± 57.6 min, P < 0.0001). Intraoperative blood loss was significantly higher in the craniotomy group (248.31 ± 94.65 versus 78.66 ± 28.96 mL, P < 0.0001). The postoperative length of stay in the intensive care unit was 12.6 days in the neuro-endoscopy group and 14.0 days in the craniotomy group with no significant difference ( P = 0.196). Intracranial pressure monitoring showed no significant difference between the two groups on postoperative days 1 and 7. Intracranial pressure was significantly higher in the craniotomy group than in the neuro-endoscopy group on postoperative day 3 (15.1 ± 6.8 versus 12.5 ± 6.8 mm Hg, P = 0.029). There was no significant difference in the mortality or outcome rate at 6 months postoperatively between the two groups. CONCLUSIONS: In patients with HICH in the basal ganglia region, neuro-endoscopy can significantly improve the hematoma clearance rate, reduce intraoperative hemorrhage and postoperative cerebral tissue edema, and improve surgical efficiency. However, the long-term prognosis of patients who undergo craniotomy through the lateral fissure is similar to that of patients who undergo neuro-endoscopic surgery.

Basal ganglia ischaemic infarction after thrombectomy: cognitive impairment at acute stage.

BACKGROUND AND PURPOSE: After successful mechanical thrombectomy for middle cerebral artery occlusion, basal ganglia infarction is commonly detectable. Whilst the functional outcome of these patients is often good, less knowledge is available about the cognitive outcome. The aim of our study was to assess the presence of cognitive impairment within 1 week after thrombectomy. METHODS: In all, 43 subjects underwent a general cognitive assessment using the Montreal Cognitive Assessment and an extensive battery of tests. Patients were classified as cognitively impaired (CImp) or not (noCImp) according to a Montreal Cognitive Assessment score below 18. RESULTS: Cognitively impaired and noCImp subjects did not differ either in their National Institutes of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS) at admittance, or in their Fazekas score and Alberta Stroke Program Early Computed Tomography Score. At discharge, CImp subjects showed higher scores than noCImp subjects on NIHSS (p = 0.002) and mRS (p < 0.001). The percentage of pathological performances on each neuropsychological test in the whole sample and in CImp and noCImp patients shows a similar cognitive profile between the groups. CONCLUSIONS: Some patients who underwent thrombectomy experienced a detectable cognitive impairment that probably led to worse NIHSS and mRS. The neuropsychological profile of such cognitive impairment at the acute stage consists of wide deficits in numerous cognitive domains, suggesting that basal ganglia damage may lead to complex functional impairments.

Pediatric intraparenchymal meningioma in the basal ganglia treated with gross total resection: a case report and review of the literature.

INTRODUCTION: Intraparenchymal meningiomas in the basal ganglia are extremely rare, and to the best of our knowledge, only three case reports have been published to date. Owing to concerns regarding major vessels, gross total resection (GTR) is difficult to achieve; therefore, subtotal resection and radiation therapy are often chosen as treatment options. We present a pediatric case with an intraparenchymal meningioma in the left basal ganglia that was successfully treated with GTR. We also reviewed the relevant literature to discuss the pathogenesis, radiological findings, and treatment methods of this rare disease. CASE REPORT: A 4-year-old girl presented with progressive right facial paralysis, aphasia, and right incomplete hemiplegia. Imaging revealed a mass lesion in the left basal ganglia and unilateral obstructive hydrocephalus. Neuroendoscopic septostomy, tumor biopsy, and cerebrospinal fluid reservoir placement were performed, and the initial pathological diagnosis was suspected glioma. Thus, craniotomy was performed to remove the tumor, which was white, elastic, and well-defined. Intraoperative rapid pathology revealed a meningioma. Postoperatively, the patient experienced transient worsening of the right incomplete hemiplegia, which subsequently improved. The final pathological diagnosis was a fibrous meningioma. CONCLUSION: Surgery for intraparenchymal meningiomas in the basal ganglia is challenging owing to the proximity of major blood vessels; however, GTR may be preferable to subtotal resection, considering the possibility of recurrence. Even in cases of intraparenchymal tumors, it is important to consider meningioma as a differential diagnosis and to carefully plan the appropriate treatment.

Stereotactic radiosurgery outcome for deep-seated cerebral arteriovenous malformations in the brainstem and thalamus/basal ganglia: systematic review and meta-analysis.

Deep-seated unruptured AVMs located in the thalamus, basal ganglia, or brainstem have a higher risk of hemorrhage compared to superficial AVMs and surgical resection is more challenging. Our systematic review and meta-analysis provide a comprehensive summary of the stereotactic radiosurgery (SRS) outcomes for deep-seated AVMs. This study follows the guidelines set forth by the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) Statement. We conducted a systematic search in December 2022 for all reports of deep-seated arteriovenous malformations treated with SRS. Thirty-four studies (2508 patients) were included. The mean obliteration rate in brainstem AVM was 67% (95% CI: 0.60-0.73), with significant inter-study heterogeneity (tau2 = 0.0113, I2 = 67%, chi2 = 55.33, df = 16, p-value < 0.01). The mean obliteration rate in basal ganglia/thalamus AVM was 65% (95% CI: 0.58-0.72) with significant inter-study heterogeneity (tau2 = 0.0150, I2 = 78%, chi2 = 81.79, df = 15, p-value < 0.01). The presence of deep draining veins (p-value: 0.02) and marginal radiation dose (p-value: 0.04) were positively correlated with obliteration rate in brainstem AVMs. The mean incidence of hemorrhage after treatment was 7% for the brainstem and 9% for basal ganglia/thalamus AVMs (95% CI: 0.05-0.09 and 95% CI: 0.05-0.12, respectively). The meta-regression analysis demonstrated a significant positive correlation (p-value < 0.001) between post-operative hemorrhagic events and several factors, including ruptured lesion, previous surgery, and Ponce C classification in basal ganglia/thalamus AVMs. The present study found that radiosurgery appears to be a safe and effective modality in treating brainstem, thalamus, and basal ganglia AVMs, as evidenced by satisfactory rates of lesion obliteration and post-surgical hemorrhage.

Laser navigation combined with XperCT technology-assisted puncture of basal ganglia intracerebral hemorrhage.

Basal ganglia hemorrhage, which is characterized by excessive incapacity charge and high mortality rates, is surgically treated by minimally invasive hematoma puncture and drainage. We aimed at determining the efficacy of laser-guided minimally invasive hematoma puncture and drainage for treatment of basal ganglia hemorrhage. A total of 61 patients with hypertensive basal ganglia hemorrhage were recruited at the Binzhou Medical University Hospital, between October 2019 and January 2021, and their clinical information retrospectively analyzed. Based on the surgical approach used, patients were assigned into either laser navigation or small bone window groups depending on the surgical approach. Then, we compared the operation times, intraoperative blood loss, clinic stay, Glasgow Outcome Score (GOS) rating at 30 days, Barthel index (BI) rating at 6 months, postoperative pneumonia incidences, and intracranial contamination complications between groups. Intraoperative blood loss, operation time, and sanatorium were significantly low in laser navigation group, relative to the small bone window group. At the same time, there were no significant differences between the groups with regard to postoperative hematoma volume, lung contamination, cerebrospinal fluid (CSF) leak, and intracranial contamination, as well as the 6-month BI and 30-day GOS rating. There were no deaths in either group. Compared with the traditional small bone window surgery, laser-guided puncture and drainage is a low-cost, accurate, and safe method for the treatment of basal ganglia hemorrhage, which is suitable for promotion in developing countries and economically underdeveloped areas.

Stereotactic and Functional Neurosurgery Convection-Enhanced Delivery of Autologous Cerebrospinal Fluid Enhances Basal Ganglia Visualization during MRI-Guided Deep Brain Stimulation Surgery.

INTRODUCTION: The aim of this study was to determine the safety and feasibility of convection-enhanced delivery of autologous cerebrospinal fluid (CSF) for enhancing intraoperative magnetic resonance imaging (MRI) of the basal ganglia during stereotactic neurosurgery. METHODS: This pilot study was conducted in 4 patients with Parkinson's disease (PD) who underwent MRI-guided deep brain stimulation of the globus pallidus internus (GPi). CSF was obtained via lumbar puncture after general anesthesia and prior to incision. A frameless stereotaxy system was installed, and an infusion catheter was inserted to the GPi using intraoperative MRI. Infusion of autologous CSF was performed at a convective rate of 5 µL/min with a maximum volume of infusion (Vi) of 500 mL. T2-weighted MRI scans were obtained every 15 min up to a maximum of 105 min in order to calculate the volume of distribution (Vd). Safety was assessed with adverse event monitoring, and clinical outcomes were measured with changes in unmedicated UPDRS part III and PDQ-39 scores from baseline to 6 months postoperatively. RESULTS: All four infusions were safe and without adverse events. The mean unmedicated UPDRS part III and PDQ-39 scores improved by 24% and 26%, respectively. The Vd:Vi ratio ranged from 2.2 to 2.8 and peaked 45 min from the onset of infusion, which is when the borders of the GPi could generally be visualized based on T2-weighted MRI. Two patients underwent refinement of the stereotactic targeting based on infusion-enhanced images. CONCLUSIONS: The convective administration of autologous CSF to deep brain structures appears safe and feasible for enhancing intraoperative MRI during stereotactic procedures. Infusion-enhanced imaging with target-specific infusates could be developed to visualize neurochemical circuits or cellular regions that currently are not seen with anatomic/structural MRI.

Arterial Supply of the Basal Ganglia: A Fiber Dissection Study.

BACKGROUND: The basal ganglia, a group of subcortical nuclei located deep in the insular cortex, are responsible for many functions such as motor learning, emotion, and behavior control. Nowadays, because it has been shown that deep brain stimulation and insular tumor surgery can be performed by endovascular treatment, the importance of the vascular anatomy of the basal ganglia is being increasingly recognized. OBJECTIVE: To explain the arterial blood supply of the basal ganglia using white matter dissection. METHODS: The Klingler protocol was used to prepare 12 silicone-injected human hemispheres. The dissections were performed from lateral to medial with the fiber dissection technique to preserve arteries. RESULTS: The globus pallidus blood supply came from the medial lenticulostriate, lateral lenticulostriate, and anterior choroidal arteries; the substantia nigra and subthalamic nucleus were supplied by the branches of posterior cerebral artery; the putamen was supplied by the lateral and medial lenticulostriate arteries; and the caudate nucleus was supplied by the lateral lenticulostriate and medial lenticulostriate arteries and the recurrent artery of Heubner. CONCLUSION: Knowledge of the detailed anatomy of the basal ganglia and its vascular supply is essential for avoiding postoperative ischemic complications in surgeries related to the insula. In addition, knowledge of this anatomy and vascular relationship opens the doors to endovascular deep brain stimulation treatment. This study provides a 3-dimensional understanding of the blood supply to the basal ganglia by examining it using the fiber dissection technique. Further studies could use advanced imaging modalities to explore the vascular relationships with critical structures in the brain.

Newly Diagnosed Adult Basal Ganglia Gliomas Treated With Laser Interstitial Thermal Therapy: A Comparative Cohort With Needle Biopsy.

BACKGROUND: Few cytoreductive surgical tools are available for newly diagnosed basal ganglia gliomas. Current reports showed high associated morbidity and mortality. Given their deep localization, laser interstitial thermal therapy (LITT) is still a rare indication. Moreover, few reports account for which of the available options have better outcomes. OBJECTIVE: To retrospectively analyze our experience with LITT and compare its safety, feasibility, and efficacy with needle biopsy for the management of adult basal ganglia gliomas. METHODS: Twenty-two patients with gliomas from the midline (e.g. thalamus and lenticular nucleus) managed with either LITT/biopsy or needle biopsy from 2015 to 2021 were included. Records regarding location, diagnosis, Karnofsky Performance Score, length of hospital stay, preoperative lesion and ablation volume, perioperative complications, and data of adjuvant treatment were collected. Overall survival was evaluated with Kaplan-Meier analysis. RESULTS: Seven patients had LITT, and 15 underwent biopsy. The overall mean age was 60.9 years (25-82 years). The average tumor volume in the former was 16.99 cm 3 and 17.65 cm 3 in the latter. No postsurgical complications were found in the LITT group, and 1 patient had a postsurgical hemorrhage after biopsy. The mean overall survival was 20.28 ± 9.63 months in the LITT group, which was greater but not statistically significant than in the biopsy group (13.85 ± 4.48 months; P = .78). CONCLUSION: Our results show that laser ablation may be both feasible and safe in adult basal ganglia gliomas. Given the lack of safe cytoreductive treatment options, LITT should be considered as a valid choice for these patients.

Optimal time window for minimally invasive surgery in treating spontaneous intracerebral hemorrhage in the basal ganglia region: a multicenter and retrospective study.

BACKGROUND: The current treatment spontaneous intracerebral hemorrhage (sICH) is limited. AIM: To determine the optimal time window for minimally invasive surgery in patients with sICH. MATERIALS AND METHODS: sICH patients with a hematoma volume of 30-80 mL in the basal ganglia region were included in our study. A total of 357 patients were divided into groups according to different operative times from ICH onset (group 1: 0-6 h, group 2: 6-12 h, group 3: >12 h) and hematoma volumes (30-50 mL and >50 mL). All patients were followed-up for three months' post-operation, and their clinical outcomes were compared. RESULTS: In the three groups of patients with hematoma volumes of 30-50 mL, the rebleeding and mortality rate were higher in group 1 than groups 2 and 3 (p < .05). The activities of daily living evaluated by Barthel Index (BI) three months' post-operation was significantly lower in group 3 than other groups (p < .05) and group 2 had the highest proportion of good outcomes. Among the patients with the hematoma volumes of 50-80 mL, the rebleeding risk was higher in group 1 than groups 2 and 3 (p < .05). However, there were no significant differences in mortality rates among these three groups. Moreover, group 1 had significantly higher BI than groups 2 and 3 (p < .05). CONCLUSIONS: Minimally invasive surgery is safe and effective in patients with sICH. 6-12 h after sICH onset is the optimal surgical window for patients with hematoma volumes of 30-50 mL, while ultra-early (≤6 h) may achieve better results in patients with hematoma volumes of >50 mL.

The Effect Of Small Bone Window Craniotomy Removal on Lactic Acid and CRP in Patients with Hypertensive Intracerebral Hemorrhage in the Basal Ganglia.

Background: Hypertensive intracerebral hemorrhage (HICH) seriously endangers the quality of life of patients and can even lead to death. Craniotomy is a common treatment method for HICH. Objective: The aim of this study was to investigate the efficacy of two different sizes of craniotomy in patients with HICH, as well as to evaluate their effects on C-reactive protein (CRP) and blood lactate levels. Materials and Methods: A total of 72 patients with HICH in the basal ganglia were operated on in our hospital from February 2017 to March 2019 and randomly divided into two groups: the small bone window (SBW) group (n = 37) and the large bone flap group (n = 35). The curative effects of the two kinds of operations were evaluated by the length of operation, the days of hospitalization, the rate of hematoma clearance, the rate of rebleeding, and the incidence of complications. Additionally, the levels of CRP and lactate were compared between the two groups. Results: The results showed that the average intraoperative time, hospital stay, rebleeding rate, and postoperative complications of patients in the SBW group were less than those in the large bone flap group. Moreover, the number of patients in the SBW group with good postoperative recovery, including class V and class IV, was higher than that in the large bone flap group. Minimally invasive craniotomy with SBW reduced the lactic acid and CRP levels more quickly than the large bone flap group. Conclusions: An SBW was superior to a large bone flap in terms of the operative effect and lactate and CRP levels. It is concluded that an SBW has significant advantages over a large bone flap.

The effect of early vs. late CT-guided stereotactic hematoma aspiration on neurological function recovery in patients with hypertensive cerebral hemorrhage in the basal ganglia: a retrospective comparative cohort study.

BACKGROUND: Surgery plays a major role in treating hypertensive cerebral hemorrhage in the basal ganglia; however, some patients suffer from neurological impairment after surgery. Studies have confirmed that stereotactic hematoma aspiration guided by computed tomography (CT) has significant value for patients with hypertensive intracerebral hemorrhage in the basal ganglia, but little is known about the optimal timing for the operation. This study sought to explore the effect of CT-guided stereotactic hematoma aspiration timing on the recovery of neurological function in patients with hypertensive cerebral hemorrhage in the basal ganglia. METHODS: The data of 110 patients with hypertensive cerebral hemorrhage in the basal ganglia admitted to the Union Hospital Tongji Medical College Huazhong University of Science and Technology from January 2021 to December 2021 were retrospectively collected. Based on the timing of their operations, the patients were allocated to the early treatment group (within 24 hours, n=50) and late treatment group (after 24 hours, n=60). The postoperative recovery of the 2 groups was compared. RESULTS: There were no significant differences in terms of age, gender, amount of cerebral hemorrhage, hemorrhage ruptured into ventricle rate, Glasgow Coma Scale score, hypertension grade, hyperlipidemia, diabetes, and operation duration between the 2 groups (P>0.05). Additionally, there was no difference in the preoperative National Institute of Health Stroke Scale scores of the patients in the 2 groups (22.50±4.90 vs. 23.83±5.35, P=0.179). Compared to the late treatment group, the National Institute of Health Stroke Scale score of the patients in the early treatment group was significantly lower 3 and 6 months after the operation (5.90±4.02 vs. 9.23±3.47, P<0.001; 4.54±2.56 vs. 6.50±3.07, P<0.001, respectively). The Glasgow Outcome Scale score of patients in the early treatment group was significantly better than that of patients in the late treatment group (P=0.035). No significant difference was found in the incidence of postoperative pulmonary infection, intracranial infection, rebleeding, and lower extremity deep venous thrombosis between the 2 groups (P>0.05). CONCLUSIONS: Early CT-guided stereotactic hematoma aspiration may improve the postoperative neurological function of patients with hypertensive cerebral hemorrhage in the basal ganglia.

[Basal Ganglia and Circuit Function:How Does the Ablation or Deep Brain Stimulation(DBS)Work?]

The basal ganglia(BG)is composed of four parallel loops: the motor, oculomotor, associative, and limbic loops. The motor loop starts from the cortex, travels through the BG and thalamus, and returns to the same area of the cortex with somatotopic organization. The striatum is the major input nucleus of the cortex, and the internal segment of the globus pallidus(GPi)is the main output nucleus. BG is explained by the direct and indirect pathways, and these excitatory or inhibitory pathways are used for several disease models. In Parkinson's disease(PD), dopamine deficiency acts on both direct and indirect pathways to cause the neuronal activity of GPi to becomes disinhibited. Pallidotomy, an effective surgery to improve Parkinsonism, aimed to destroy this hyperactive state. This is based on the rate model. However, a simian PD model with MPTP-treated monkeys exhibited increased GPi activity during effective stimulation of subtalamic nucleus(STN)-DBS, which makes it difficult to explain the pathophysiology of PD based only on the rate model. Instead, the alterative model is now widely prevailing. Local field potentials recorded from the DBS leads implanted in GPi and/or STN uncovered the abnormally synchronized activity in the ß range(ß oscillation)and abnormal co-synchronization between these nuclei, which is believed to be important in the pathophysiology of PD.

[Practical Anatomy of the Basal Ganglia].

Anatomical knowledge of target structures is essential in stereotactic functional neurosurgery. Thus, we created a three-dimensional(3D)atlas comprising frozen sections and histologically stained slides prepared from cadaveric brains. Herein, we describe the anatomical information of stereotactic functional neurosurgery targets gained from our atlas. The subthalamic nucleus(STN)was found to be clearly enclosed by neural fibers with high neuronal density. Based on our 3D models, the mean penetration length of deep brain stimulation leading into the STN was 6.6 mm. The globus pallidus was found to be clearly divided into the grobus pallidus externus(GPe)and internus(GPi)by its neural fibers, and the optic tract was located below the GPi. Although the thalamic lateral nuclear group(ventrooralis, ventrontermedius, and ventrocaudalis)could not be identified from either macroscopic frozen sections or MR images, these structures were clearly discernible from each other based on cell architecture(cell size and cell density)when viewed under a microscope. In contrast, distinguishing ventral and dorsal nuclei in humans is difficult. In addition to the main targets of the basal ganglia, we also investigated the anatomy of other targets in detail(posterior subthalamic area, pedunclopontine nucleus, nucleus accumbens, and nucleus basalis of Meynert). Overall, this anatomical knowledge from the atlas helps functional neurosurgeons interpret intraoperative microelectrode recording and MRI more precisely, helping facilitate more accurate surgeries.

Gamma Knife Radiosurgery for Cavernous Malformations of Basal Ganglia and Thalamus: A Retrospective Study of 53 Patients.

INTRODUCTION: Gamma Knife radiosurgery (GKRS) has been used to treat cavernous malformations (CMs) located in basal ganglia and thalamus. However, previous reports are limited by small patient population. METHODS: We retrospectively reviewed the clinical and radiological data of 53 patients with CMs of basal ganglia and thalamus who underwent GKRS at West China Hospital between May 2009 and July 2018. All patients suffered at least once bleeding before GKRS. The mean volume of these lesions was 1.77 cm3, and the mean marginal dose was 13.2 Gy. After treatment, patients were followed to determine the change in symptom and hemorrhage event. RESULTS: The mean follow-up period was 52.1 months (6.2-104.3 months). The calculated annual hemorrhage rate (AHR) was 48.5% prior to GKRS and 3.0% after treatment (p < 0.001). The Kaplan-Meier analysis revealed that 2-, 3-, and 5-year hemorrhage-free survival were 88, 80.9, and 80.9%, respectively. Preexisting symptoms were resolved in 11 patients, improved in 14, and stable in 5. Only 2 patients (3.8%) developed new neurological deficit. CONCLUSION: Our study suggests that AHR after GKRS was comparable to the recorded AHR of natural history (3.1-4.1%) in previous studies. GKRS is a safe and effective treatment modality for CMs of basal ganglia and thalamus. Considering the relative insufficient understanding of natural history of CMs, future study warrants longer follow-up.

The Thalamic Arteriovenous Malformations Have Better Prognosis than Basal Ganglia Malformations Regarding Obliteration: Prognostic Factors Analysis.

BACKGROUND: Arteriovenous malformations (AVMs) are rare vascular congenital lesions that affect mainly patients during their productive years of life. In order to obtain a better quality of life for patients with this disease, a multidisciplinary approach is recommended. Radiosurgery is one of the treatment modalities available for AVMs, but many factors may influence the effectiveness of this strategy. Classically, it has been said that deep-seated lesions have a particular behavior compared with AVMs in other regions, but a differentiation between thalamic lesions and those located in the basal ganglia has not been made. METHODS: Institutional records for central core AVMs treated with radiosurgery between January 2004 and January 2014 were retrospectively analyzed. Brainstem lesions were excluded from the analysis. RESULTS: Forty-nine patients with deep-seated AVMs were included. Forty-three (87.8%) were located in the thalamus and 6 (12.2%) in the area of basal ganglia. The nidus mean volume was 4.1 cm3 (SD: 4.1), the maximum diameter mean was of 19.5 mm (SD: 8.0). The prescription dose was 18.2 Gy (SD: 2.1), and the follow-up time was 75.8 months (SD: 32.5). There was a greater obliteration rate in thalamic AVMs compared with those located in the basal ganglia: 81.4% versus 33.3% (P = 0.026), respectively. There was no association between categorical variables and obliteration rate. CONCLUSIONS: Stereotactic radiosurgery is a good option for patients with thalamic and basal ganglia AVMs, but a multidisciplinary approach to decision-making is mandatory in order to achieve the best results.

The concept of "Four Walls, Two Poles" in the lesions of the thalamus and ganglion regions: case report and literature review.

BACKGROUND: There are few articles about the surgical techniques of thalamic glioma and the lesions in the basal ganglia area. According to three existing cases and the literature review (Twelve articles were summarized which mainly described the surgical techniques), we discuss the surgical characteristics of lesions of the thalamus and basal ganglia area and summarize the relevant surgical skills. CASE PRESENTATION: Of the three cases, two were thalamic gliomas and one was brain abscess in basal ganglia. According to the three-dimensional concept of the "Four Walls, Two Poles", lesions of the thalamus and basal ganglia were surgically removed, and the operative effect was analysed by relevant surgical techniques. Surgical resection of the lesions of the thalamus and basal ganglia area according to the three-dimensional concept of the "Four Walls, Two Poles" has achieved good surgical results. Relevant surgical techniques, such as the use of retractors, the use of aspirators, the choice of surgical approaches, and the haemostasis strategy, also played an important role in the operation process. CONCLUSIONS: In the presented three cases the three-dimensional concept of the "Four Walls, Two Poles" allowed for safe surgical resection of lesions of the thalamus and basal ganglia.