PurposeTo analyze the pathways to brainstem tumors in childhood, as well as safe entry zones.MethodWe conducted a retrospective study of 207 patients less than 18 years old who underwent brainstem tumor resection by the first author (Cavalheiro, S.) at the Neurosurgical Service and Pediatric Oncology Institute of the São Paulo Federal University from 1991 to 2011.ResultsBrainstem tumors corresponded to 9.1 % of all pediatric tumors operated in that same period. Eleven previously described “safe entry zones” were used. We describe a new safe zone located in the superior ventral pons, which we named supratrigeminal approach. The operative mortality seen in the first 2 months after surgery was 1.9 % (four patients), and the morbidity rate was 21.2 %.ConclusionsAnatomic knowledge of intrinsic and extrinsic brainstem structures, in association with a refined neurosurgical technique assisted by intraoperative monitoring, and surgical planning based on magnetic resonance imaging (MRI) and tractography have allowed for wide resection of brainstem lesions with low mortality and acceptable morbidity rates.

Knowledge of the surgical anatomy provides improvement for microsurgical approaches. The evolution from a small opening to a resection of the tentorium absolutely changed the exposure of the mediobasal aspect of the temporal lobe. The SCTT approach with tentorial resection is an excellent alternative route to the posterior part of mediobasal aspect of the temporal lobe, and it was enough to achieve the best neurosurgical management of tumoral and vascular lesions located in this area.

Melanotic schwannoma (MS) is an unusual variant of nerve sheath neoplasm. Only 10% of these tumors will undergo malignant degeneration, with exceedingly rare reported metastasis. We present a 32-year-old woman with a 6-month history of cervical pain and left arm progressive weakness. Neurological examination showed a left upper limb radicular pain, with pyramidal syndrome at C5 level. The magnetic resonance imaging (MRI) study highlighted an intradural extramedullary heterogeneous mass along the spinal cord at the C4–C5 level, slightly hyperintense with T1 and hypointense with T2-weighted sequences, invading the left neural foramen. The patient underwent C3–C5 laminectomy with total resection of a black tumor. In the postoperative period, a patent deficit of shoulder abduction ensued related to the nervous section. Microscopically, compactly fascicles of spindle-shaped cells with pleomorphic and hypercromatic nuclei, dark brown intracellular pigments, as well as some mitotic figures were seen. Immunohistochemical stains for S-100, Human Melanoma Black-45 (HMB-45), and vimentin were positive, with Ki-67 labelling index (LI) of 15% compatible with MS. Six months after radiotherapy she presents local recurrence and lung metastatic dissemination of the MS. She underwent left pulmonary segmentectomy, followed by chemotherapy and radiosurgery. The patient developed a febrile neutropenia and worsening of general status, and died after 3 months due to respiratory complications. MS are rare tumors with potential for local recurrence and distal metastasis. Complete surgical resection remains as the treatment of choice, once the uncommon cases with malignant progression shows low response to chemo and radiotherapy.

The frontotemporosphenoidal craniotomy, usually denominated pterional craniotomy, was first described by Yasargil in 1975 and is one of the earliest landmarks of the advents of microneurosurgery [1][2][3] . This approach enables, specifically, the exposure of the entire frontoparietal operculum 4,5 , the opening of the entire sylvian fissure 6,7 and all anterior cisterns of the encephalon base 2,5 , which makes both the pterional craniotomy and the transylvian approach the widest used techniques in today's neurosurgery practice.Over the past decades, the pterional craniotomy has undergone a systematization modified by several authors, what also gave rise to more extended types of craniotomies 8,9 . Among then, the supraorbital craniotomy 10 and the orbitofrontozygomatic craniotomy 10-13 stands out. This review offered a detailed description of the technique we use nowadays for this procedure, with modifications arising from its extensive use since its initial proposal, seeking to optimize all its stages, the access and opening of the cisterns, as well as minimize brain retraction. DESCRIPTION OF PROCEDUREPositioning -the patient should be placed supine, with the shoulder at the edge of the surgical table in a neutral position, and head and neck remain suspended after removal of the head support. The head should be secured by a three-pin skull fixation devise (Mayfield or Sugita model) and must be maintained above the level of the right atrium to facilitate venous return. In order to avoid the head holder position to hinder the surgeon' s procedure, the ipsilateral pin of the operative field should be set on the mastoid region, while the two contralateral pins should be on the contralateral superior temporal line, above the temporal muscle, that should not be transfixed. The pin corresponding to the ipsilateral mastoid and the most anterior one corresponding to the contralateral superior temporal line must be in parallel position to prevent any head movement, especially during future traction of cranial wraps made with the aid of fish-hooks.There is a sequence of five movements for the positioning of the head: traction, lifting, deflection, rotation and torsion. ABSTRACTThis review intended to describe in a didactic and practical manner the frontotemporosphenoidal craniotomy, which is usually known as pterional craniotomy and constitute the cranial approach mostly utilized in the modern neurosurgery. This is, then, basically a descriptive text, divided according to the main stages involved in this procedure, and describes with details how the authors currently perform this craniotomy.Key words: craniotomy, microsurgery, neurosurgery. RESUMOA presente revisão visou descrever de forma didática e prática a realização da craniotomia frontotemporoesfenoidal, usualmente denominada pterional, que constitui a craniotomia mais utilizada na prática neurocirúrgica atual. Trata-se, portanto, de um texto fundamentalmente descritivo, dividido conforme as principais etapas envolvidas na realização desse procedimento, que mostr...

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OBJECTIVE The authors report a novel surgical route from a superior anatomical aspect-the contralateral anterior interhemispheric-transcallosal-transrostral approach-to a lesion located in the subcallosal region. The neurosurgical approach to the subcallosal region is challenging due to its deep location and close relationship with important vascular structures. Anterior and inferior routes to the subcallosal region have been described but risk damaging the branches of the anterior cerebral artery. METHODS Three formalin-fixed and silicone-injected adult cadaveric heads were studied to demonstrate the relationships between the transventricular surgical approach and the subcallosal region. The surgical, clinical, and radiological history of a 39-year-old man with a subcallosal cavernous malformation was retrospectively used to document the neurological examination and radiographic parameters of such a case. RESULTS The contralateral anterior interhemispheric-transcallosal-transrostral approach provides access to the subcallosal area that also includes the inferior portion of the pericallosal cistern, lamina terminalis cistern, the paraterminal and paraolfactory gyri, and the anterior surface of the optic chiasm. The approach avoids the neurocritical perforating branches of the anterior communicating artery. CONCLUSIONS The contralateral anterior interhemispheric-transcallosal-transrostral approach may be an alternative route to subcallosal area lesions, with less risk to the branches of the anterior cerebral artery, particularly the anterior communicating artery perforators.

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