Resection of the quadrangular lobule of the cerebellum to increase exposure of the cerebellomesencephalic fissure: an anatomical study with clinical correlation.

OBJECTIVE: The lateral aspect of the cerebellomesencephalic fissure frequently harbors vascular pathology and is a common surgical corridor used to access the pons tegmentum, as well as the cerebellum and its superior and middle peduncles. The quadrangular lobule of the cerebellum (QLC) represents an obstacle to reach these structures. The authors sought to analyze and compare exposure of the cerebellar interpeduncular region (CIPR) before and after QLC resection and provide a case series to evaluate its clinical applicability. METHODS: Forty-two sides of human brainstems were prepared with Klingler's method and dissected. The exposure area before and after resection of the QLC was measured and statistically studied. A case series of 59 patients who underwent QLC resection for the treatment of CIPR lesions was presented and clinical outcomes were evaluated at 1-year follow-up. RESULTS: The anteroposterior surgical corridor of the CIPR increased by 10.3 mm after resection of the QLC. The mean exposure areas were 42 mm2 before resection of the QLC and 159.6 mm2 after resection. In this series, ataxia, extrapyramidal syndrome, and akinetic mutism were found after surgery. However, all these cases resolved within 1 year of follow-up. Modified Rankin Scale score improved by 1 grade, on average. CONCLUSIONS: QLC resection significantly increased the exposure area, mainly in the anteroposterior axis. This surgical strategy appears to be safe and may help the neurosurgeon when operating on the lateral aspect of the cerebellomesencephalic fissure.

Survival analysis and prognostic factors in posterior fossa ependymomas in children and adolescents.

OBJECTIVE: In this study, the authors aimed to analyze the overall survival (OS) and progression-free survival (PFS) of patients younger than 18 years of age who were diagnosed with posterior fossa ependymomas, and to identify prognostic factors such as the degree of resection, tumor topography, and involvement of the lesion in the hindbrain. METHODS: The authors performed a retrospective cohort study of patients younger than 18 years of age, treated beginning in 2000, with a diagnosis of posterior fossa ependymoma. Ependymomas were separated into three groups: tumors restricted to the fourth ventricle, tumors inside the fourth ventricle and exiting from the foramen of Luschka, and tumors inside the fourth ventricle and completely surrounding the hindbrain. Furthermore, the tumors were classified by molecular group using the staining method for H3K27me3. Statistical analysis was performed using Kaplan-Meier survival curves, with p < 0.05 considered statistically significant. RESULTS: Of 1693 patients who underwent surgical treatment between January 2000 and May 2021, 55 patients who met the inclusion criteria were included. The median age at diagnosis was 2.98 years. The median OS was 44 months, and the survival rates at 1, 5, and 10 years were 92.5%, 49.1%, and 38.3%, respectively. The cases were assigned to two posterior fossa ependymoma molecular groups: 35 (63.6%) cases to group A and 8 (14.5%) to group B. The median ages in groups A and B were 2.94 and 2.85 years and the median OS values were 44 and 38 months, respectively (p = 0.9245). Statistical analysis was performed on multiple variables, including age, sex, histological grade, Ki-67 expression, tumor volume, extent of resection, and adjuvant therapies. The median PFS of patients with dorsal-only involvement was 28 months; for dorsolateral involvement, it was 15 months; and for total involvement, it was 9.5 months (p = 0.0464). No statistically significant difference was found for OS. There was a statistically significant difference between the proportion of patients in whom gross-total resection was achieved in the dorsal-only involvement group (73.1%, 19/26) and those in the total involvement group (0%, 0/6) (p = 0.0019). CONCLUSIONS: This study confirmed that the extent of resection has an impact on OS and PFS. The authors found that adjuvant radiotherapy resulted in a higher OS but did not prevent progression, that the pattern of involvement of the brainstem in the tumor at diagnosis could elicit important information regarding the patient's prognosis regarding PFS, and that the total involvement of the rhombencephalon impaired the gross-total resection of these tumors.

Microsurgical approaches to the cerebellar interpeduncular region: qualitative and quantitative analysis.

OBJECTIVE: The cerebellar interpeduncular region (CIPR) is a gate for dorsolateral pontine and cerebellar lesions accessed through the supracerebellar infratentorial approach (SCITa), the occipital transtentorial approach (OTa), or the subtemporal transtentorial approach (STa). The authors sought to compare the exposures of the CIPR region that each of these approaches provided. METHODS: Three approaches were performed bilaterally in eight silicone-injected cadaveric heads. The working area, area of exposure, depth of the surgical corridor, length of the interpeduncular sulcus (IPS) exposed, and bridging veins were statistically studied and compared based on each approach. RESULTS: The OTa provided the largest working area (1421 mm2; p < 0.0001) and the longest surgical corridor (6.75 cm; p = 0.0006). Compared with the SCITa, the STa provided a larger exposure area (249.3 mm2; p = 0.0148) and exposed more of the length of the IPS (1.15 cm; p = 0.0484). The most bridging veins were encountered with the SCITa; however, no significant differences were found between this approach and the other approaches (p > 0.05). CONCLUSIONS: To reach the CIPR, the STa provided a more extensive exposure area and more linear exposure than did the SCITa. The OTa offered a larger working area than the SCIT and the STa; however, the OTa had the most extensive surgical corridor. These data may help neurosurgeons select the most appropriate approach for lesions of the CIPR.

Orbitofrontal sulcal and gyrus pattern in human: an anatomical study.

UNLABELLED: The anatomical characterization of the orbitofrontal cortex in human is limited in literature instead of many functional and clinical studies involving it. OBJECTIVE: Anatomically define the orbitofrontal region aiming to possible neurosurgical treatments and unify the scientific nomenclature as well. METHOD: We analyze eighty four human hemispheres using a surgical microscope. Then we chose four hemispheres and dissect them according to Klinger' technique. RESULTS: We found five main sulcus: olfatory sulcus, orbital medial sulcus, orbital lateral sulcus, orbital transverse sulcus and orbital intermediate sulcus. These sulcus, excluding the intermediate sulcus, delimit five gyrus: rectus gurys, orbital medial gyrus, orbital anterior gyrus, orbital lateral gyrus and orbital posterior gyrus. The main sulcal configuration can be divided on four more frequently patterns. CONCLUSION: Orbitofrontal cortex is associated with many psychiatric disorders. Better anatomical and functional characterization of the orbitofrontal cortex and its connections will improve our knowledge about these diseases.

Intrasphenoid septations inserted into the internal carotid arteries: a frequent and risky relationship in transsphenoidal surgeries / Septações intraesfenoidais inseridas nas artérias carotídeas internas: uma relação frequente e arriscada nas cirurgias transesfenoidais

Abstract Introduction: When an expanded endonasal transsphenoidal surgical approach is performed, intrasphenoid septations must be completely resected. If these structures are close to the internal carotid artery (ICA), then their manipulation might cause vascular injury. Objective: The objective of this study is to describe the frequency of intrasphenoid septations in the internal carotid artery protuberance (ICAp). Methods: Computed tomography (CT) scans of 421 patients were analysed. Intrasphenoid septations (classified as intersphenoid or accessory) and their relationship to the ICAp were described. Additionally, a sphenoid sinus classification was performed based on their degree of pneumatisation to determine whether a difference exists in the frequency of intrasphenoid septations inserted into ICAp with regard to sinus type. Results: The patient mean age was 39 ± 21.4 years. Overall, 219 patients (52%) had septations in the ICAp; 359 patients (85.3%) had intersphenoid septations; of the latter, 135 (37.6%) had septations in the ICAp. This frequency was higher among patients with sphenoid sinus type 4 or 5 (44.7% and 43.5%, respectively). Accessory septations were found in 255 patients (60.6%); 140 of these septations (54.9%) were in the ICAp. Among 351 patients with types 3, 4 or 5 sphenoid sinuses (i.e., only well-pneumatised sphenoid sinuses), 219 (62.4%) had septations in the ICAp. These frequencies are higher than those reported in most previous studies. Conclusion: The frequency of intrasphenoid septations in the ICAp found is considerable. It is higher among patients with more pneumatised sinuses. This finding justifies an appropriate pre-operative study, and careful attention must be paid during transsphenoidal surgery.

Resumo Introdução: Quando uma abordagem cirúrgica transesfenoidal endonasal ampliada é feita, septações intraesfenoidais devem ser completamente ressecadas. Se essas estruturas estiverem próximas à artéria carótida interna (ACI), a manipulação pode causar lesão vascular. Objetivo: O objetivo deste estudo foi descrever a frequência de septações intraesfenoidais na protuberância da artéria carótida interna (pACI). Método: Exames de tomografia computadorizada (TC) de 421 pacientes foram analisados. As septações intraesfenoidais (classificadas como interesfenoidais ou acessórias) e sua relação com a pACI foram descritas. Além disso, uma classificação do seio esfenoidal foi feita com base no seu grau de pneumatização para determinar se existe uma diferença na frequência de septações intraesfenoidais inseridas em pACI em relação ao tipo de seio. Resultados: Pacientes com idade média de 39 ± 21,4 anos foram incluídos. No geral, 219 pacientes (52%) apresentavam septações na pACI; 359 (85,3%) septações interesfenoidais; 135 (37,6%) septações na pACI. Essa frequência foi maior entre os pacientes com seio esfenoidal tipo 4 ou 5 (44,7 e 43,5%, respectivamente). As septações acessórias foram encontradas em 255 doentes (60,6%); 140 dessas septações (54,9%) estavam na pACI. Entre 351 pacientes com seios esfenoidais tipos 3, 4 ou 5 (isto é, apenas seios esfenoidais bem pneumatizados), 219 (62,4%) tinham septações na pACI. Essas frequências são superiores às relatadas na maioria dos estudos. Conclusão: A frequência de septações intraesfenoidais na pACI encontrada é considerável, é maior entre pacientes com seios mais pneumatizados. Esse achado justifica um estudo pré-operatório adequado e uma atenção especial deve ser dada durante a cirurgia transesfenoidal.

Anaplastic Ganglioglioma of the Pineal Region ­ A Case Report

Introduction Gangliogliomas are tumors commonly found in the temporal lobe and related to seizures; their appearance in the pineal region is rarely described. This report characterizes the first case of anaplastic ganglioglioma of the pineal region. Case Report The authors describe the case of a 32-year-old woman that developed progressive headache. An MRI investigation revealed a pineal tumor. The patient tested negative for biomarkers and underwent surgery through supracerebellar infratentorial approach and achieved gross total resection of the tumor in a challenging location. Pathological analysis revealed a biphasic neoplasm with the following two distinct phenotypes in separate fields: an immature neuronal component with several atypical mitoses and a mature astrocytic component with bipolar cells, microcysts, and eosinophilic bodies. The Ki67/MIB1 proliferation index was 20­30% in localized hotspots. Based on the pathological findings, the tumor was defined as an anaplastic ganglioglioma World Health Organization (WHO) grade III. Discussion/Conclusion Gangliogliomas are classified as glioneural neoplasms based on the histologic findings described as a mixture of neoplastic astrocytes and neurons. Moreover, these tumors represent 0.4­1.3% of tumors of the central nervous system. Authors describe de novo anaplastic ganglioglioma as 1% of the largest series. Gross total resection and adjuvant treatment may play important role in patients' prognostic. In this case, due to the malignant anaplastic component of her tumor, the patient received treatment with temozolamide and radiotherapy after gross total resection of the lesion.

Introdução Gangliogliomas são tumores comumente encontrados no lobo temporal e se relacionam com crises epilépticas; o aparecimento desses tumores na região da pineal é raramente descrito. Este relato caracteriza o primeiro caso de ganglioglioma anaplásico da região da pineal. Relato de Caso Paciente do sexo feminino, 32 anos, apresentou-se com cefaleia de piora progressiva. Investigação com ressonância magnética revelou tumor na região da pineal. Os biomarcadores para tumores da pineal foram negativos e a paciente foi submetida a microcirurgia com o acesso supracerebelar e infratentorial atingindo ressecção total da lesão. A análise patológica revelou neoplasia bifásica com dois fenótipos distintos em campos separados: um componente era composto por células neuronais imaturas com inúmeras mitoses atípicas e o segundo componente era composto por astrócitos maduros, microcistos e corpos eosinofílicos. Foi encontrado um índice proliferativo Ki67/M1B1 de 20­30%. Baseado nos achados anatomopatológicos, o tumor foi definido como ganglioglioma anaplásico grau III da OMS. Discussão/Conclusão Gangliogliomas são classificados como neoplasias glioneurais baseado nos achados histológicos descritos como misto de neoplasia neuronal e glial; esses tumores representam 0,4­1,3% de todos os tumores do sistema nervoso central. Ganglioglioma anaplásico de novo tem sido descrido em 1% nas maiores series de gangliogliomas. Ressecção total da lesão e tratamento adjuvante desempenham um papel importante no prognóstico dos pacientes. Devido ao componente anaplásico do tumor em questão, a paciente foi tratada com temozolamida e radioterapia após ressecção total da lesão.

Orbitofrontal sulcal and gyrus pattern in human: an anatomical study / Padrões de sulcos e giros orbitofrontais em humanos: um estudo anatômico

The anatomical characterization of the orbitofrontal cortex in human is limited in literature instead of many functional and clinical studies involving it. Objective Anatomically define the orbitofrontal region aiming to possible neurosurgical treatments and unify the scientific nomenclature as well. Method We analyze eighty four human hemispheres using a surgical microscope. Then we chose four hemispheres and dissect them according to Klinger’ technique. Results We found five main sulcus: olfatory sulcus, orbital medial sulcus, orbital lateral sulcus, orbital transverse sulcus and orbital intermediate sulcus. These sulcus, excluding the intermediate sulcus, delimit five gyrus: rectus gurys, orbital medial gyrus, orbital anterior gyrus, orbital lateral gyrus and orbital posterior gyrus. The main sulcal configuration can be divided on four more frequently patterns. Conclusion Orbitofrontal cortex is associated with many psychiatric disorders. Better anatomical and functional characterization of the orbitofrontal cortex and its connections will improve our knowledge about these diseases. .

A caracterização do córtex orbitofrontal em humanos é limitada na literatura, a despeito de estudos funcionais e clínicos envolvendo-o. Objetivo Definir anatomicamente o córtex orbitofrontal visualizando possíveis tratamentos neurocirúrgicos e unificar a nomenclatura científica. Método Analisamos oitenta e quatro hemisférios cerebrais humanos usando um microscópio neurocirúrgico. Escolhemos quatro hemisférios e os dissecamos de acordo com a técnica de Klinger para expor a substância branca subcortical. Resultados Encontramos cinco principais sulcos: sulco olfatório, sulco orbital medial, sulco orbital lateral, sulco orbital transverso e sulco orbital intermediário. Estes sulcos, excluindo o sulco orbital intermediário, delimitaram cinco giros: giro reto, giro orbital medial, giro orbital anterior, giro orbital lateral e giro orbital posterior. A conformação de sulcos e giros orbitais pôde ser dividida em quatro padrões mais frequentes. Conclusão O córtex orbitofrontal é associado com várias desordens psiquiátricas. Uma melhora caracterização anatômica, funcional e de suas conexões melhorará nosso conhecimento destas desordens. .

Reversible Obstructive Hydrocephalus from Hypertensive Encephalopathy: A Condition that Neurosurgeons Must Know / Hidrocefalia obstrutiva reversível secundária a encefalopatia hipertensiva: uma condição que o neurocirurgião deve conhecer

The vasogenic edema in structures of posterior fossa secondary to elevated hydrostatic pressure can cause obstructive hydrocephalus, a condition called "reversible obstructive hydrocephalus from hypertensive encephalopathy." A case of a 27-year-old woman with arterial hypertension and sign of raised intracranial pressure is reported. Her radiologic studies have showed vasogenic cerebellar edema without structural lesion. This edema leads to obstruction of the cerebral aqueduct. We discuss the clinical and therapeutic aspects of this condition. In this clinical situation, the accurate control of blood pressure is themain goal on medical care, and the need of permanent ventricular shunt is quite infrequent.

O edema vasogênico secundário a elevação da pressão hidrostática capilar pode causar hidrocefalia obstrutiva, a chamada Hidrocefalia Obstrutiva Reversível secundária a Encefalopatia Hipertensiva. Nós apresentamos umcaso de umamulher de 27 anos com hipertensão arterial e sinais de hipertensão intracraniana. Sua investigação radiológica evidenciou sinais de edema vasogênico cerebelar bilateral sem lesão estrutural, determinando obstrução do aqueduto cerebral Nós discutimos os aspectos clínicos e terapêuticos deste caso. Nesta condição, o adequado controle da pressão arterial é a principal medida terapêutica, sendo a necessidade de derivação liquórica permanente infrequente.