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.Keywords: neurosurgery, craniotomy, microsurgery, far-lateral approach.RESUMO 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.Palavras-chave: neurocirurgia, craniotomia, extremo-lateral, microcirurgia.Approaching lesions located in the lower clivus and at the anterior edge of foramen magnum have always presented as a challenge to the neurosurgeon. The majority of these lesions have been approached posteriorly by suboccipital or retrosigmoid craniotomies and anteriorly by trans-oral and through the paranasal sinus approaches. Nevertheless all of then have disadvantages including a great depth of surgical field and an extremely limited lateral exposure 1 . Once the high morbidity and mortality of lesions located at so an important anatomic region, the improvement of these posterior approaches is imperative, in order to increase the surgical exposure and reduce the retraction of neurovascular structures.The far lateral approach is the one composed by the dissection of occipital-cervical muscles with the exposition of suboccipital triangle, the lateral suboccipital craniotomy and finally the exposure of vertebral artery since its entrance into the dura mater 2

The cerebral cortex folding in humans allow that an extensive area of cerebral cortex fit into the limited space of the skull. The factors that guide this folding are complex and its final result leads to sulci and gyrus patterns in adult brain. These patterns, depending on the region of cerebral cortex analyzed, can have or not a high degree of variability 1 . There are some evidence that factors guiding the cerebral cortex folding starts in the beginning of cerebral morphogenesis. First, in a coronal brain slice, we can see that sulcus in the inferior and lateral surface of the brain are oriented toward the ventricular cavity and sulcus in the medial surface are oriented parallel to corpus callosum fibers. (In cases of total corpus callosum agenesis, the sulcus in the medial surface seems to be ventricular-guided too). Second, neurons sends axons across the corpus callosum even before the neuron migration process end 2 , and this neuronal projection affect the final brain morphology 3 . Based on these observations, we can suppose that the final brain morphology depends on neuronal migration, axonal connection and probably others factors.The frontal lobe has four surfaces: a lateral, a medial, a basal and a sylvian surface 4 . The basal surface is in contact with the orbital roof, compounded of the frontal, ethmoid and sphenoid bones being, for this reason, called orbitofrontal surface.In the last ten years, many studies have showed the relationship between altered orbitofrontal cortical pattern and ABSTRACTThe 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.

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.

Background: Merkel cell carcinoma (MCC) is a rare neuroendocrine skin tumor. In our knowledge, only 30 cases of brain metastasis were reported in literature. The authors report a case of 57-year-old male with elevated intracranial pressure signs, which a frontal mass with pathological diagnosis of MCC. Case Description: A 57-year-old male was admitted with a 3-month history of progressive headache, associated with nausea and dizziness. The magnetic resonance imaging showed a left frontal lobe, parasagittal, and nodular lesion with perilesional edema. The patient underwent complete surgical resection with success. The adjuvant treatment was radiotherapy and chemotherapy. Conclusion: In our knowledge, there is a little number of cases of MCC reported in literature. Surgical management is considered in cases with intracranial hypertension or focal signs. The adjuvant treatment options are immunotherapy and radiotherapy.

Introduction: Delayed cerebral ischemia (DCI) is one of the main determinants of prognosis in aneurysmal subarachnoid hemorrhage (aSAH). Hypertension induction (HI) and inotropics are frequently used strategies to treat DCI. However, little is known about clinical improvement immediately after those therapies. Methods: All patients with aSAH admitted to our hospital from 2016 to 2018 were evaluated. DCI was defined as a new focal neurological deficit or decrease in level of consciousness or the appearance of new infarctions on brain imaging. Patients who developed DCI and received vasopressors or inotropics and were included in the study. They were evaluated before (t0), 45 (t1) and 90 (t2) minutes after therapy initiation using NIHSS scores and Glasgow Coma Scale (GCS). Results: A total of 98 aSAH were evaluated, and 21 of them developed DCI (21.4%). Six patients received both treatment strategies, leading to a total of 27 DCI treatments (norepinephrine =12, milrinone =15). Mean NIHSS score had a significant decrease in t1 and t2 when compared to t0 (17 [95%CI 13-24], 16 [95%CI 11-23], 15 [95%CI 9-22], p<0.001 and p<0.002). The same happened among those treated with IH (t0=18 [95%CI 13-25]; t1=16 [95%CI 11-23], p=0.002; t2=14 [95%CI 9-22], p=0.027) and with milrinone (t0=17 [95%CI 12-24]; t1=15 [95%CI 10-23], p=0.007; t2=14 [95%CI 9-23], p=0.001). Mean GCS had a significant improvement in t1, that was not sustained in t2 (9 [95%CI 8-11], 10 [95%CI 9-12], 10 [95%CI 9-12], p=0.008 and p=0.098). In those treated with HI GCS scores did not change significantly (t0=9 [95%CI 7-11]; t1=10 [95%CI 8-12], p=0.054; t2=10 [95%CI 8-12], p=0.177). Those treated with inotropics significantly improved across time (t0=10 [95%CI 8-12]; t1=11 [95%CI 9-13], p=0.004; t2=11 [95%CI 9-13], p=0.001). Conclusions: DCI treatment with HI or inotropic therapy seems effective in immediately improving neurological deficits in patients with aSAH and DCI.

The role of Transcranial Doppler (TCD) in monitoring patients with subarachnoid hemorrhage (SAH) for delayed cerebral ischemia (DCI) is well established. However, the response and kinetics of TCD blood flow velocities (BFV) to treatment of DCI has been scarcely investigated. We assessed the hypothesis that TCD BFV decrease progressively after treatment of DCI with vasopressors or inotropics. Methods: All patients with SAH admitted to a tertiary hospital neurocritical unit were evaluated with daily TCD exams for monitoring for DCI from June 2016 to June 2018. DCI was defined as the development of new focal neurological signs and/or deterioration in level of consciousness, lasting for more than 1 h, or the appearance of new infarctions on neuroimaging. Patients who developed DCI and were treated with vasopressors or inotropics were prospectively included in this study. TCD exams were performed immediately before (t0), 1 hour (t1) and 2 hours after (t2) the initiation of therapy for DCI by the same neurosonologist. Clinical and physiological data before and during exams were recorded. Results: 27 DCI treatments with either norepinephrine (n=12) or milrinone (n=15) in 21 patients were monitored. Patients were mainly females (88.9%, mean age 50.41+/- 12.52 year-old) with low grade clinical SAH (44.4% World Federation of Neurosurgeons Scale 1 and 2) but with high modified Fisher scores (81.1% with modified Fisher score of 3 and 4). DCI occurred 11.6+/- 3.4 days from the initial bleeding. Cerebral BFV significantly dropped after treatment (t0=158.08 +/- 42.84 cm/s; t1=146.71+/- 42.19 cm/s; t2=136.46+/-44.43 cm/s, p&lt;0.01). There was also a significant drop in the National Institutes of Health stroke scale scores after therapy (t0= 13 [ 8, 19]; t1 12 [6, 19]; t2 9 [6, 19], p&lt; 0.01). Patients treated with milrinone had a greater decline in cerebral BFV compared to those treated with norepinephrine (milrinone: t0 203.14+/- 49.41 cm/s; t1 183.14 +/-35.44 cm/s; t2= 167.86 +/- 37.55 cm/s, p=0.04 versus norepinephrine t0=156 +/- 27.45 cm/s; t1=164.58 +/- 40.48 cm/s; t2=159.0 +/- 48.24 cm/s, p=0.67). Conclusion: TCD BFV decrease progressively with hemodynamic therapy for DCI. Use of milrinone was associated with a greater decline in BFV when compared to norepinephrine.

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