3-Step didactic white matter dissection of human cerebellum: Micro-neuroanatomical training.

OBJECTIVES: A thorough understanding of cerebellum anatomy is essential in 4th ventricle approaches (more frequent in pediatric neurosurgery), avoiding relevant complications such as cerebellar mutism. The aim of the present work is to show the feasibility of a didactic dissection of human cerebellum focusing on cerebellar peduncles and dentate nucleus (DN), which are structures at high risk during these surgical procedures. MATERIAL AND METHODS: The cerebellum was dissected according to the Klingler method for white matter, using standard and specific microsurgery tools. Surgical microscope magnification (×6-×40) provided by a D.F. Vasconcellos M900 was required. A Canon EOS T7 18-55 mm digital camera was used and Adobe Lightroom Classic CC and Keynote were selected as photo enhancing software. Special methods such as LED light endoscopic transillumination were used for photographical reasons. RESULTS: DN dissection was successfully achieved and the relations between these nucleus and the cerebellar peduncles, inferior vermis and medullary velums were described. Through this three steps dissection guide (1. tentorial surface; 2. suboccipital surface; 3. 4th ventricle structures), the most relevant anatomical structures were shown and its implications in different 4th ventricle approaches were characterised. CONCLUSION: 3 D perspective provided by real specimen anatomical dissection is critical for learning neuroanatomy. LED transillumination was shown as a useful technique for the 4th ventricle structures photographic documentation which improves spatial recognition. This benefit can be applied for the study of the relations between the medullary velums and the rhomboid fossa foramina, which are permeable to light. The proposed three-steps dissection guide helps to a better understanding of human cerebellum and to gain self-confidence, allowing safer practice for neurosurgeons in all stages of their career.

From Above and Below: The Microsurgical Anatomy of Endoscopic Endonasal and Transcranial Microsurgical Approaches to the Parasellar Region.

INTRODUCTION: The parasellar region is one of the most complex of the skull base. In this study, we review the anatomy and approaches to this region through a 360° perspective, correlating microsurgical and endoscopic anatomic nuances of this area. METHODS: An endoscopic endonasal approach (EEA) and microsurgical dissections were performed. The parasellar anatomy is reviewed and common areas of tumor extensions are assessed. Surgical approaches are discussed based on the anatomic nuances of those regions. RESULTS: The cavernous sinus (CS) can be divided into 2 spaces: posterosuperior, above and behind the internal carotid artery (ICA); and anterior, in front of the cavernous ICA. Those spaces can be approached through the CS walls: anterior and/or medial wall via EEA; or superior and/or lateral wall via transcranial approaches. The relationship of the Meckel cave, adjacent to the lateral and posterior wall of the CS, is relevant for surgical planning. Areas often affected by tumor extension can be divided into 6 regions: superior (cisternal), superolateral (parapeduncular), posterolateral (Meckel cave and petrous bone), medial (sella), anterior (superior orbital fissure), and anterior inferior (pterygopalatine fossa). Anatomic and technical nuances of each of those regions should be taken into consideration when dealing with tumors in the parasellar space. CONCLUSIONS: A transcranial approach and EEA provide effective access to the parasellar region. Management of cavernous sinus and Meckel cave tumors requires familiarity with those approaches. Understanding of the surgical anatomy of the parasellar region, from above and below, is therefore necessary for adequate surgical planning and execution.

Desarrollo de técnicas microquirúrgicas usando tinción vascular con y sin silicona en placenta humana con modelos craneales 3D / Development of microsurgical techniques using vascular staining with and without silicone in human placenta with 3D cranial models

En las ultimas décadas, ha habido un cambio en la formación en las especialidades quirúrgicas, lo cual ha llevado a plantearse la necesidad de adquisición de habilidades por fuera del quirófano por medio de la simulación. El objetivo de este trabajo es demostrar que el uso de placentas humanas con modelo craneal tridimensional (3D), es un método de alta fidelidad y retroalimentación para el desarrollo de técnicas microquirúrgicas. Se realizó un estudio de evaluación técnica en el Laboratorio de Microcirugía Dr. Evandro de Oliveira del Hospital de la Beneficiencia de Portugal de São Paulo, utilizando 15 placentas con técnicas de coloración y preservación vascular con silicona para moldes; realizando ejercicio de anastomosis vasculares, ejercicios de disección parenquimatosa placentaria que remedan la disección aracnoidea y del valle silviano, además de simulación de resección de tumores. Cualitativamente la placenta humana es un método con alta fidelidad y retroalimentación, además, es de acceso universal para la adquisición de habilidades microquirúrgicas, que asociada a un modelo craneal 3D permite el perfeccionamiento de craneotomías, coordinación visomotriz, propiocepción y relación de profundidad que se requieren para abordajes neuroquirúrgicos.

In the last decades, there has been a change in training in surgical specialties, which has led to the need to acquire skills outside the operating room through simulation. The aim of this work is to demonstrate that the use of human placentas with a three-dimensional (3D) cranial model is a high fidelity and feedback method for the development of microsurgical techniques. A technical evaluation study was carried out in the Dr. Evandro de Oliveira Microsurgery Laboratory of the Hospital de la Beneficiencia de Portugal in São Paulo, using 15 placentas with coloration techniques and vascular preservation with silicone for molds; performing vascular anastomosis, placental parenchymal dissection exercises that mimic arachnoid and sylvian fissure dissection, in addition to simulating tumor resection. Qualitatively, the human placenta is a method with high fidelity and feedback, and it is also universally accessible for the acquisition of microsurgical skills, which, associated with a 3D cranial model, allows the refinement of the craniotomies, visomotor coordination, proprioception, and depth relationship required for neurosurgical approaches.

3-Step didactic white matter dissection of human cerebellum: Micro-neuroanatomical training. / Disección didáctica de fibra blanca en cerebelo humano en tres pasos: entrenamiento microneuroanatómico.

OBJECTIVES: A thorough understanding of cerebellum anatomy is essential in 4th ventricle approaches (more frequent in pediatric neurosurgery), avoiding relevant complications such as cerebellar mutism. The aim of the present work is to show the feasibility of a didactic dissection of human cerebellum focusing on cerebellar peduncles and dentate nucleus (DN), which are structures at high risk during these surgical procedures. MATERIAL AND METHODS: The cerebellum was dissected according to the Klingler method for white matter, using standard and specific microsurgery tools. Surgical microscope magnification (x6-x40) provided by a D.F. Vasconcellos M900 was required. A Canon EOS T7 18-55 mm digital camera was used and Adobe Lightroom Classic CC and Keynote were selected as photo enhancing software. Special methods such as LED light endoscopic transillumination were used for photographical reasons. RESULTS: DN dissection was successfully achieved and the relations between these nucleus and the cerebellar peduncles, inferior vermis and medullary velums were described. Through this three steps dissection guide (1. tentorial surface; 2. suboccipital surface; 3. 4th ventricle structures), the most relevant anatomical structures were shown and its implications in different 4th ventricle approaches were characterised. CONCLUSION: 3 D perspective provided by real specimen anatomical dissection is critical for learning neuroanatomy. LED transillumination was shown as a useful technique for the 4th ventricle structures photographic documentation which improves spatial recognition. This benefit can be applied for the study of the relations between the medullary velums and the rhomboid fossa foramina, which are permeable to light. The proposed three-steps dissection guide helps to a better understanding of human cerebellum and to gain self-confidence, allowing safer practice for neurosurgeons in all stages of their career.

Suboccipital Lateral Approach for Resection of Cerebellopontine Angle Meningioma: Operative Video and Technical Nuances.

We present the case of a 34-year-old woman, who presented to our department with a 4 months history of dizziness, hearing loss, and tinnitus on the right side. MRI (magnetic resonance imaging) scan demonstrated a large extra-axial lesion, suggestive of a meningioma, with dural attachments to the petrosal bone surface and tentorium, closely related with the trigeminal, abducens, facial, vestibulocochlear, and lower cranial nerves in the right side. Treatment options were discussed with the patient, and surgical resection was selected to remove the lesion, and decompress the cranial nerves and brainstem. The surgery was performed with a patient in a semi-seated position with head placed in a flexed, nonrotated position. A right lateral suboccipital approach was performed, exposing the right transverse and sigmoid sinuses. After dura opening, microsurgical dissection was used to open the cisterna magna, and obtain cerebellum relaxation. That was followed by identification of cranial nerves VII-XII and then identification of the tumor itself. Tumor debulking was then performed with use of suction and ultrasonic aspirator. After extensive resection, the tumor margins were dissected away from brainstem, cerebellum, and cranial nerves. Finally, the tumor attachment to the tentorium was coagulated and cut and the tumor was completely removed. Postoperative MRI confirmed complete resection of the tumor. The patient was discharged on the 1st week after surgery, with no additional postoperative deficits or complications. The link to the video can be found at: https://youtu.be/aZ3jhZTAeAA .

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.

Orbitozygomatic craniotomy in three pieces: tips and tricks.

OBJECTIVE: Didactically describe the orbitozygomatic craniotomy made in three pieces. METHOD: This approach was performed, from 2002 to 2011, in 49 patients admitted at Beneficência Portuguesa of São Paulo Hospital. RESULTS: Twenty-seven patients had vascular lesions and twenty-two suffered for intracranial skull base tumors. The vascular lesions varied from cavernous angiomas inside the mesencephalum, high bifurcation basilar tip aneurysms, superior cerebellar arteries aneurysms and arteriovenous malformations in the interpeduncular cistern. Skull base tumors as meningiomas, interpeduncular hamartomas and third ventricle floor gliomas were among the neoplastic lesions approached. We had no permanent injuries and minimal transient complications had occurred. CONCLUSION: It is a descriptive text, organized in the sequence of the main stages in which such a craniotomy is performed, describing in details the technique in which this group of evolutionarily authors came to accomplish the task.

Orbitozygomatic craniotomy in three pieces: tips and tricks / Craniotomia orbitozigomática em três peças: dicas e truques

ABSTRACT Objective Didactically describe the orbitozygomatic craniotomy made in three pieces. Method This approach was performed, from 2002 to 2011, in 49 patients admitted at Beneficência Portuguesa of São Paulo Hospital. Results Twenty-seven patients had vascular lesions and twenty-two suffered for intracranial skull base tumors. The vascular lesions varied from cavernous angiomas inside the mesencephalum, high bifurcation basilar tip aneurysms, superior cerebellar arteries aneurysms and arteriovenous malformations in the interpeduncular cistern. Skull base tumors as meningiomas, interpeduncular hamartomas and third ventricle floor gliomas were among the neoplastic lesions approached. We had no permanent injuries and minimal transient complications had occurred. Conclusion It is a descriptive text, organized in the sequence of the main stages in which such a craniotomy is performed, describing in details the technique in which this group of evolutionarily authors came to accomplish the task.

RESUMO Objetivo Descrever didaticamente a craniotomia orbitozigomática realizada em três peças. Método Esse acesso foi realizado em 49 pacientes, de 2002 a 2011 em pacientes admitidos no Hospital Beneficência Portuguesa de São Paulo. Resultados Vinte e sete pacientes apresentavam lesões vasculares e vinte e dois sofriam de tumores da base do crânio. As lesões vasculares variaram entre angiomas cavernosos do mesencéfalo, aneurismas topo da artéria basilar com bifurcações altas, aneurismas da artéria cerebelas superior a malformações arteriovenosas na cisterna interpeduncular. Tumores da base do crânio como meningeomas, hamartomas interpedunculares e gliomas no assoalho do terceiro ventrículo estão entre as lesões neoplásicas abordadas. Nós não tivemos sequelas definitivas e tivemos mínimas complicações temporárias. Conclusão Trata-se de um texto descritivo, dividido conforme as principais etapas da realização desta craniotomia, o qual descreve com detalhes a técnica com que o presente grupo de autores evolutivamente veio a realizá-la.

The far-lateral craniotomy: tips and tricks.

This article intends to describe in a didactical and practical manner the suboccipital far-lateral craniotomy. This is then basically a descriptive text, divided according to the main stages involved in this procedure, and that describes with details how the authors currently perform this craniotomy.

The far-lateral craniotomy: tips and tricks / A craniotomia extremo-lateral: dicas e truques

This article intends to describe in a didactical and practical manner the suboccipital far-lateral craniotomy. This is then basically a descriptive text, divided according to the main stages involved in this procedure, and that describes with details how the authors currently perform this craniotomy.

O presente artigo visa descrever de forma didática e prática a realização da craniotomia suboccipital extremo-lateral. Trata-se, portanto, de um texto fundamentalmente descritivo, dividido conforme as principais etapas da realização dessa craniotomia, e que descreve com detalhes a técnica com que o presente grupo de autores evolutivamente veio a realizá-la.

Pretemporal craniotomy.

This paper aims to describe the performance of the pretemporal craniotomy performed didactically from 2002 to 2012 in eighty patients. It is therefore a fundamentally descriptive text, organized in the sequence of the main stages in which such a craniotomy is performed, and describing in detail the technique with which this group of evolutionarily authors came to accomplish the task.

Pretemporal craniotomy / Craniotomia pre temporal

This paper aims to describe the performance of the pretemporal craniotomy performed didactically from 2002 to 2012 in eighty patients. It is therefore a fundamentally descriptive text, organized in the sequence of the main stages in which such a craniotomy is performed, and describing in detail the technique with which this group of evolutionarily authors came to accomplish the task.

O presente artigo visa descrever de forma didática e prática a realização da craniotomia pré-temporal aplicada em oitenta pacientes de 2002 a 2012. Trata-se, portanto, de um texto fundamentalmente descritivo, dividido conforme as principais etapas da realização desta craniotomia, e que descreve com detalhes a técnica com que o presente grupo de autores evolutivamente veio a realizá-la.