Pseudotumoral Presentation of Cerebral Amyloid-Beta Angiopathy: Case Report and Review of Literature.

OBJECTIVE: Cerebral amyloid angiopathy-related inflammation (CAA-RI) is a rare and potentially treatable encephalopathy that usually affects people older than 50 years old and has an acute or subacute clinical presentation characterized by rapidly evolving cognitive decline, focal deficits and seizures. In a small subset of patients the disease can adopt a pseudotumoral form in the neuroimages that represents a very difficult diagnostic challenge. METHODS: Here in we report a patient with a tumour-like presentation of histopathologically confirmed CAA-RI. RESULTS: We also conducted a search and reviewed the clinical and radiological features of 41 cases of pseudotumoral CAA-RI previously reported in the literature in order to identify those characteristics that should raise diagnostic suspicions of the disease, there by avoiding unnecessary surgical treatments. CONCLUSION: The therapy of CAA-RI with steroids is usually effective and clinical and radiological remission can be achieved in the first month in approximately 70% of cases.

Assessment of accessibility to the diagnosis and treatment of brain tumors in Argentina: Preliminary results.

BACKGROUND: As far as public health is concerned, brain tumors burden is significant despite their low incidence, because they comprise high direct costs (specific diagnostic resources, high complexity treatments, and rehabilitation) and high-unforeseen costs (labor leave, family, and social issues). Although the Argentine's Health System is supposed to provide healthcare to all the population, it would not guarantee equity of access for brain tumors treatment. In order to analyze this hypothesis we decided to carry out a survey to obtain data on access, availability and resources for tumor management in Argentina. METHODS: An online questionnaire with eight dimensions and 29 queries was conducted addressing all professionals involved in tumor management. Two variables were generated: (1) type of medical center according to their financial support, and (2) the geographic region (GeoR). Analysis of association between these variables and the accessibility to different resources was performed with Chi-square and Fisher's exact test. Multivariate analyses through multiple logistic regression models were also tested. RESULTS: One hundred and fourteen surveys were collected from 56 state-managed centers and 55 private/trade-union managed centers. Responders came from 15 provinces grouped into integrated GeoR. Results and analysis of each dimension were reported. CONCLUSION: The data obtained provides information about the accessibility to brain tumors treatment, exposing the unequal distribution of human and technologic resources in Argentina. This problem exceeds the limits of public health to become a bioethical problem. We think these results could be essentially associated to our health system fragmented structure, and the large geographical extension of our country. Finally, we believe that collaboration of professional associations working together with public and private sector authorities responsible for financial resources and logistic should bring a principle of solution.

Germinoma with involvement of midline and off-midline intracranial structures.

Germinomas are malignant intracranial germ tumors, usually found in suprasellar regions. Less than 10% are localized in off-middle structures, and synchronous involvement of both structures has only exceptionally been published. A case of an 18-year-old male patient with progressive right-sided hemiparesis and panhypopituitarism was reviewed. Brain MRI showed a solid mass involving pituitary and hypothalamus with thickening of pituitary stalk, high intensity lesions on T2-weighted imaging in left internal capsule, caudate nucleus, globus pallidus, and mild atrophy of the left internal capsule and cerebral peduncle. Nonadenomatous lesions were considered in the differential diagnosis. Alfa-fetoprotein (AFP) levels were negative in both serum and cerebrospinal fluid (CSF), while ß -human chorionic gonadotrophin ( ß -HCG) levels were slightly increased in CSF. A transsphenoidal biopsy identified a germinoma. Four cycles of chemotherapy with bleomicine, etoposide, and cysplatin were given, followed by radiotherapy, but patients died due to a recidiva. Conclusion. Germinoma must be considered in patients with insipidus diabetes with a sellar mass with thickening of pituitary stalk; and ectopic germinoma must be suspected in patients with slowly progressive hemiparesis with cerebral hemiatrophy. Even with a rare condition, colocalization of midline and off-midline germinoma must be suspected in the presence of these typical signs of both localizations.

Spontaneous intraparenchymal otogenic pneumocephalus: A case report and review of literature.

BACKGROUND: Pneumocephalus is commonly associated with head and facial trauma, ear infection, or surgical interventions. Spontaneous pneumocephalus caused by a primary defect at the temporal bone level without association with pathological conditions is very rare. Few cases have been published with purely intraparenchymal involvement. We describe a rare case of spontaneous pneumocephalus arising from the mastoid cells with intraparenchymal location and present an extensive review of the existing literature. CASE DESCRIPTION: A 57-year-old woman presented a brief episode of sudden otalgia in her left ear that was followed by a motor aphasia. Imaging revealed a left temporal intraparenchymal pneumocephalus in a close relationship with a highly pneumatized temporal bone. Left temporal craniotomy and decompression were performed. Further subtemporal exploration confirmed a dural defect and other osseous defects in the tegmen tympani, which were both consequently closed watertight. CONCLUSION: Although extremely rare, a spontaneous intraparenchymal pneumocephalus with mastoidal origin should be considered as a possible diagnosis in patients with suggestive otological symptoms and other non-specific neurological manifestations. Surgery is indicated to repair bone and dural defects.

Three-piece orbitozygomatic approach.

OBJECTIVE: To describe the technical details of a 3-piece orbitozygomatic approach. INTRODUCTION: In a 3-piece orbitozygomatic approach, soft tissue exposure is mostly comparable to the classic frontopterional approach. Osseous resection is a 3-piece operation that consists of first performing anterior and posterior cuts along the zygomatic arch, reflecting it down, attached to the masseter. This is followed by a classic frontotemporosphenoidal craniotomy, and finally, an osteotomy of the orbital rim, roof, and lateral wall of the orbit. RESULTS: When compared with its 1- and 2-piece counterparts, 3-piece orbitozygomatic craniotomy, as described here, is a relatively simple operation and is thus advisable when considering an anterior or middle fossa approach. Brain exposure is wide, whereas cerebral retraction is minimal. We recommend avoiding orbit sectioning as deep as the superior orbital fissure. CONCLUSION: The modifications described herein show the technical features of the 3-piece orbitozygomatic approach, which provides excellent brain exposure with less retraction and a good cosmetic result.

Anatomical landmarks for positioning the head in preparation for the transsphenoidal approach: the spheno-sellar point.

The transnasal approach is the most utilized approach to the sellar region. This study was conducted to identify an anatomical landmark on the lateral surface of the head that corresponds to the midpoint of the sellar floor at the level of sphenoidal rostrum. This point, lined up with the nostril, simulates the surgical path and facilitates the transnasal access to the sella turcica. Four adult, formalin-fixed and silicon-injected cadaveric heads, and ten dried skulls were used for laboratory dissection. The heads and skulls were sectioned along the midline; and the spheno-sellar point, corresponding to the midpoint of the sellar floor at the level of sphenoid rostrum, was determined. The spheno-sellar point was plotted on the lateral surface of the skull, and its position measured relative to the external acoustic meatus. Linking the spheno-sellar point with the nostril created the spheno-nostril line. This line represents the surgical path to be taken for direct access to the sphenoid rostrum, and was used to align the cadaveric heads as in surgery. The endonasal transsphenoidal approach was then utilized in one hundred and two adult patients with sellar lesions, using the spheno-sellar point and the spheno-nostril line as the superficial landmarks to guide the approach. The results of this clinical experience are summarized. The spheno-sellar point was found to be located an average of 40.1 mm (SD+/-2.9 mm) anterior and 23.3 mm (SD+/-3.2 mm) superior to the external acoustic meatus. The spheno-nostril line represents the straight surgical path to the sphenoidal rostrum. This landmark was used in 102 correlative transnasal surgeries for sellar lesions of adult patients, and has allowed an easy and straightforward access to the sella. In only 3 cases with poor pneumatisation of the sphenoid sinus (presellar type), the actual location of the surgical instruments had to be confirmed by fluoroscopy. The application of the spheno-sellar point and the spheno-nostril line is a fast, reliable and very simple way to facilitate transsphenoidal surgery, and their use may avoid complications associated with misdirection of this approach. Its use may be limited in cases of poor pneumatisation of the sphenoid sinus, where fluoroscopic guidance could be necessary as a rule.

Apoplejía de adenomas hipofisarios: Reporte de cuatro casos / Pituitary apoplexy: Report of 4 cases

Objective. To describe four cases of patients with pituitary tumor apoplexyMaterial and method. We analyzed the information of four patients with pituitary tumor apoplexy. Results. One patient had acromegaly and the apoplexy happened during a treatment with lanreotido. The other three cases were patients with non functional pituitary tumors. All the cases were operated by endonasal transsphenoidal approach. Conclusion. Classic manifestations of pituitary tumor apoplexy include severe headache, visual field defects, and ophthalmoplegia. In the absence of contraindications, transsphenoidal decompression is recommended in most patients. pituitary tumor apoplexy include severe headache, visual field defects, and ophthalmoplegia. In the absence of contraindications, transsphenoidal decompression is recommended in most patients.

Anatomía microquirúrgica de los ostia esfenoidales / Microsurgical anatomy of the sphenoid sinus ostiae

Objective. To determine the variability of the position of the ostia of the sphenoid sinus. Method. Thirty two dry skulls were examined under X6 magnification. The septae and nasal conchae were removed in order to expose the anterior wall of the sphenoid sinus. A caliper was used for measurements.Results. We found two ostia in each skull, except in one case (the left ostium was absent). In just four skulls the inferior edges of both ostia were found in the same height. In just one skull the superior edges of both ostia were found in the same height. The distance from the internal edge of the right ostium to midline is, on average, 2.04 mm (from 0.3 to 5.3 mm). The distance from the internal edge of the left ostium to midline is, on average, 2.18 mm (from 0.2 to 5.1 mm). Conclusion. A great variability exists of the position of the ostia of the sphenoid sinus. This knowledge is useful when a transsphenoidal surgery is carried out.

Abordaje orbitocigomático en tres piezas: Nota técnica / Three piece orbito-zygomatic approach

Objetivo. Describir los detalles técnicos del abordaje orbitocigomático en tres piezas. Descripción. La exposición de partes blandas no difiere mayormente de la efectuada en una craneotomía frontopterional. La resección ósea es realizada en tres piezas, en el siguiente orden: 1) dos cortes, uno anterior y otro posterior, sobre el arco cigomático. Luego, dicho arco es llevado hacia abajo, junto con el músculo masetero; 2) craneotomía fronto-temporo-esfenoidal clásica; y 3) resección del reborde orbitario junto con su techo y su pared lateral. Conclusiones. Las modificaciones descriptas en este trabajo permiten realizar, en forma fácil y segura, un abordaje orbitocigomático que permite una excelente exposición cerebral sin retracción, con muy buenos resultados cosméticos.

La insoportable pasividad de la clase teórica / The unbearable passivity at the theoretical lecture

Resultados. El formato “estándar” de la clase teórica no es efectivo si el objetivo es que los alumnos retengan y comprendan los temas más relevantes para su futuro desempeño profesional. Las clases teóricas promueven un aprendizaje pasivo y este tipo de aprendizaje NO es la forma más eficiente de aprender. Los estudiantes aprenden mejor cuando toman un rol activo en su proceso de aprendizaje. En este problema educativo tenemos como cómplices a nuestros alumnos. En general los estudiantes no leen para las clases. Como los alumnos no leen previamente el docente no tiene otra opción que dar una clase teórica. El Constructivismo nos aporta una posibilidad de romper este círculo vicioso que nos fuerza a utilizar un método inefectivo de enseñanza.Esta corriente pedagógica ve el aprendizaje como un proceso en el cual el estudiante construye activamente nuevos conceptos. Pero para aplicar las técnicas del constructivismo se requiere que los alumnos lean los contenidos en forma previa a la clase. ¿Cómo lograrlo? Comenzando cada clase con una evaluación sobre sus contenidos. De esta manera el docente puede dedicar tiempo de la clase a resolver problemas clínicos y así desarrollar habilidades de pensamiento crítico de sus alumnos.

Localización del surco central en pacientes con tumores cerebrales cercanos a la corteza sensitivo-motora utilizando omega contralateral / Contralateral omega sign for the localization of the central sulcus by patients with cerebral tumors next to the sensory-motor area

Objetivo: Determinar la utilidad de la identificación del surco central contralateral a la lesión, a través de Omega invertida, como método para localizar la corteza sensitivomotora adyacente al proceso tumoral. Método: Desde julio de 2005 hasta abril de 2007, fueron operadas por el primer autor (AC) 15 pacientes con lesiones cercanas o a nivel de la corteza sensitivomotora, utilizando el signo de Omega contralateral a la lesión. Además, fueron estudiados 5 cerebros (10 hemisferios) de cadáveres adultos fijados en formol. Resultados: El surco central separa la corteza motora de la sensitiva. Presenta tres rodillas o curvas. La rodilla media, es la resposable de la forma de Omega invertida que muestra el surco central en un corte axial. En promedio, la altura de Omega fue de 11.2mm +/- 3.35mm, y el ancho, en su base, de 15.7mm +/- 2.48mm. Por otro lado, la distancia promedio desde el borde medial de Omega hasta la línea media fue de 24.5mm +/- 5.35mm. En los 15 casos se estudió detenidamente la resonancia magnética (corte axial) antes de la cirugía, para poder identificar el surco central a través del signo de Omega, en el hemisferio contralateral a la lesión. En todos los casos excepto uno, fue posible identificar dicho signo. De los quince pacientes operados, siete mostraron déficit motor previo a la cirugía (1 plejía, 1 paresia severa, 1 paresia moderada y 4 paresias leves). En todos los casos hubo una mejoría en el postoperatorio. Los ocho pacientes restantes no presentaron déficit motor antes de la cirugía. Luego del procedimiento quirúrgico, dichos enfermos continuaron sin presentar déficit motor. Conclusión: El signo de Omega contralateral puede, fácil y eficientemente, ser utilizado para identificar la relación entre una lesión y el surco central ipsilateral.

Relación entre la porción extracraneana del nervio facial y el arco cigomático: triángulo cigomático-facial / Relationship between the extracranial portion of the facial nerve and the zygomatic arch: zygomatic-facial triangle

Objetivo.Determinar larelación entre la porción extracraneana del nervio facial y el arco cigomático.Método. Estudiamos 4 cabezas cadavéricas (8 regiones parotídeas),fijadas en formol e inyectadas con silicona coloreada.Resultados. El nervio facial tiene 6 porciones. La extracraneanacomienza cuando el nervio atraviesa el foramen estilomasteoideo y corre dentrode la parótida. Anterior al trago el nervio se ubica a 26,88 mm debajo del arcosuperior del arco cigamático. Desde ese punto el nervio toma una direcciónsuperoanterior, cruzando el cigoma 18,65 mm por delante del trago. Así dibujaun triángulo (cigomático-facial), con 3 puntos: a) sobre el borde superior delcigoma, a nivel del borde anterior del trago; b) 26 mm por debajo del punto a)y c) 18 mm por delante del punto a) podemos trazar un área de trabajo libre,sin riesgo de dañar el facial.Conclusión. El triángulo cigomaticofacial es un reparo útil paratrabajar debajo del arco cigomático con bajo riesgo de dañar al facial.

Objective: To determine the relationship between the extracranialportion of the seventh nerve and the zygomatic arch.Method: We studied 4 cadaveric heads (8 parotid regions) formaline fixedand injected with coloured silicone. A surgical microscope was used to performthe disections. Measures were taken with a caliper.Results: The facial nerve has 6 portions. The extracranial portionstarts when the nerve traverses the stylomastoid foramen, running inside theparotid gland. Just anterior to the tragus, the nerve is located 26.88 mm belowthe superior edge of the zygomatic arch. From that point, the nerve takes asuperior and anterior direction, crossing the zygomatic arch 18.65 mm ahead ofthe tragus. Thus, drawing a triangle (zygomatic-facial triangle), with threepoints: a) over the superior edge of the zygomatic arch, at the level of theanterior border of the tragus, b) 26 mm below the point a, and c) 18 mm aheadthe point a, we can trace a safe area of working, without risk of damage of thefacial nerve.Conclusion: The zygomatic-facial triangle is a very useful landmark forto work below the zygomatic arch with a low risk of damage of the facial nerve.

Estudio anatómico de los pares xii yvii extracraneanos en la anastomosis hipogloso-facial / Anatomic study of extracranial pairs xii and vii in the hypoglossal-facial anastomosis

Objetivo:analizar laanatomía microquirúrgica de los nervios facial e hipogloso extracraneana enrelación con la anastomosis hipogloso-facial.Método: en cinco cabezas cadavéricas adultas, formolizadas e inyectadascon silicona coloreada, se reprodujeron tres técnicas de anastomosis hipogloso-facialcon magnificación (clásica, Sawamura e injerto) y se tomaron medidas de laporción extracraneana de los nervios facial e hipogloso empleadas paratrasponer y unir un nervio con el otro y su proyección cutánea.Resultados: las distancias promedio obtenidas fueron: bifurcación facialhasta el sector horizontal del hipogloso 31,56 mm, sector mastoideo del facial16,35, de la porción extracraneana del facial hasta su bifurcación 18,93 mm ydesde la piel 21,16 mm. En el 100 % de los nervios faciales estudiados suporción extracraneana prebifurcación se encontró por debajo de un cuadriláteroauditivomastoideo ubicado 2 cm por debajo del conducto auditivo externo.Conclusión: la proyección cutánea de la porción extracraneanaprebifurcación del facial fue constante mientras que el resto de las medidastuvieron una ligera variación.

Objective: to analize the microsurgical anatomy of the extracranialhypoglossal and facial nerves in relationship with hypoglosso- facialanastomosis.Method: in five cadaveric heads, formolized and silicone coloured, weperformed with magnification three techniques of hypoglosso-facial anastomosis(classic, Sawamura and nerve grafting) and we measured the extracranialportions of the hypoglossal and facial nerves used in their anastomosis andtransposition and, its cutaneous proyection.Results: the average distances obtained were: from the facial nervebifurcation to the horizontal portion of the hypoglossal nerve 31.56 mm, facialnerve mastoidal portion 16.35 mm, from the facial nerve extracranial portion toits bifurcation 18.93 mm and from the skin 21.16 mm. The 100 % of the facialnerves prebifurcation extracranial portions studied were under anauditory-mastoid quadrilateral space located 2 cm beneath the external auditorycanal.Conclusion: the cutaneous proyection of the facial nerve prebifurcationextracranial portion was constant but the other measures obtained showedvariations.

Comparacion de tecnicas de reconstruccion empleadas en cirugia de plexo braquial entre las lesiones supra e infraclaviculares / Comparison of brachial plexus surgical reconstruction techniques used between supra and infraclavicular lesions

Objective: to compare the thecnical procedures used for reconstruction in different groups of traumatic brachial plexus lesions (TBPL): supra and infraclavicular. Methods: all cases of brachial plexus lesions operated between September 2002 and March 2004 were included. Each case was analyzed separately and included in one of the two groups. Results: a total of 12 lesions were included in this presentation. Out of these, 8 were supraclavicular lesions, wich required neurorraphy in 4 nerves or trunks, neurotization in 11, and neurolisis in one. There were 4 infraclavicular lesions: 4 required neurolisis, and 2 neurorraphy. Conclusion: Eachs group of TBPL required a different surgical reconstruction technique (AU)

El foramen yugular: anatomia microquirurgica y abordajes / Yugular foramen: microsurgical anatomy and approaches

Objective: to describe the anatomy and the operative approaches to the jugular foramen. Method: twenty dry heads and four formalin-fixed adults heads injected with silicon were examined. We performed measurements of the jugular foramen in the dry heads and the operative approaches in a stepwise manner in the formalin - fixed heads. Results: the jugular foramen is divided into three compartments: the petrosal (inferior petrosal sinus), the intrajugular (glossopharyngeal, vagus, and accesory nerves) and the sigmoid (sigmoid sinus) parts. In 65 por ciento dry heads the right foramen was larger than the left, in 5 por ciento equal, and in 30 por ciento smaller than the left. The length of the jugular foramen was 14.29mm from the endocranial view and 15,10mm from the exocranial view. The approaches to the jugular foramen are the retrosigmoid, the far-lateral paracondylar, the transmastoid infralabyrinthine and the preauricular infratemporal. Conclusion: the operative approaches to the jugular foramen can be categorized into three groups: 1)a posterior group directed through the posterior cranial fossa, 2) a lateral group directed through the mastoid bone, and 3) an anterior group directed through the tympanic bone (AU)

Comparacion de tecnicas de reconstruccion empleadas en cirugia de plexo braquial entre las lesiones supra e infraclaviculares / Comparison of brachial plexus surgical reconstruction techniques used between supra and infraclavicular lesions

Objective: to compare the thecnical procedures used for reconstruction in different groups of traumatic brachial plexus lesions (TBPL): supra and infraclavicular. Methods: all cases of brachial plexus lesions operated between September 2002 and March 2004 were included. Each case was analyzed separately and included in one of the two groups. Results: a total of 12 lesions were included in this presentation. Out of these, 8 were supraclavicular lesions, wich required neurorraphy in 4 nerves or trunks, neurotization in 11, and neurolisis in one. There were 4 infraclavicular lesions: 4 required neurolisis, and 2 neurorraphy. Conclusion: Eachs group of TBPL required a different surgical reconstruction technique

El foramen yugular: anatomia microquirurgica y abordajes / Yugular foramen: microsurgical anatomy and approaches

Objective: to describe the anatomy and the operative approaches to the jugular foramen. Method: twenty dry heads and four formalin-fixed adults heads injected with silicon were examined. We performed measurements of the jugular foramen in the dry heads and the operative approaches in a stepwise manner in the formalin - fixed heads. Results: the jugular foramen is divided into three compartments: the petrosal (inferior petrosal sinus), the intrajugular (glossopharyngeal, vagus, and accesory nerves) and the sigmoid (sigmoid sinus) parts. In 65 por ciento dry heads the right foramen was larger than the left, in 5 por ciento equal, and in 30 por ciento smaller than the left. The length of the jugular foramen was 14.29mm from the endocranial view and 15,10mm from the exocranial view. The approaches to the jugular foramen are the retrosigmoid, the far-lateral paracondylar, the transmastoid infralabyrinthine and the preauricular infratemporal. Conclusion: the operative approaches to the jugular foramen can be categorized into three groups: 1)a posterior group directed through the posterior cranial fossa, 2) a lateral group directed through the mastoid bone, and 3) an anterior group directed through the tympanic bone

Craneotomía bajo sedación para resección de tumor de fosa cerebral posterior guiada con técnica estereotáxica; reporte de un caso / Awake craniotomy for posterior cerebral fossa tumor resection-case report

La craneotomía bajo sedación para la resección de tumores en la corteza cerebral es una técnica bien establecida que permite el mejor abordaje con una mínima disfunción neurológica (corteza motora y área de la palabra de Broca en el lóbulo frontal, y área de la palabra de Wernicke en el lóbulo temporal). Nosotros reseñamos la técnica anestésica utilizada en la resección de un tumor cerebeloso metastásico en una paciente de sexo femenino de 71 años de edad, tabaquista severa, con un tumor pulmonar sin diagnóstico histológico previo. Con la paciente en posición supina, y bajo una sedación con midazolam y petidina IV, se realizó una broncoscopía con fibrobroncoscopio y una biopsia endobraquial. A continuación se llevó a cabo una marcación estereotáxica guiada por imágenes de tomografía axial computada (TAC), la craneotomía y la resección del tumor. El hombro izquierdo de la paciente fue elevado con compresas, y la cabeza se giró hacia la derecha a fin de mejorar el acceso a la fosa cerebral posterior. Para la craneotomía utilizamos midazolam-droperidol-fentanilo por vía IV más sevofluorano a bajas concentraciones >(0,5-1,5 por ciento) a través de una cánula nasal con oxígeno a 3 l/min. El monitoreo consistió en pulsioximetría, electrocardiografía, medición de la tensión arterial no invasiva ciclada en forma automática, frecuencia respiratoria y crapnografía. El tiempo total de cirugía fue de 285 minutos, siendo bien tolerada. La paciente fue transferida a la Sala de Cuidados Postanestésicos 50 minutos después de finalizada la operación, y dada de alta del hospital después de tres días. (AU)

Craneotomía bajo sedación para resección de tumor de fosa cerebral posterior guiada con técnica estereotáxica; reporte de un caso / Awake craniotomy for posterior cerebral fossa tumor resection-case report

La craneotomía bajo sedación para la resección de tumores en la corteza cerebral es una técnica bien establecida que permite el mejor abordaje con una mínima disfunción neurológica (corteza motora y área de la palabra de Broca en el lóbulo frontal, y área de la palabra de Wernicke en el lóbulo temporal). Nosotros reseñamos la técnica anestésica utilizada en la resección de un tumor cerebeloso metastásico en una paciente de sexo femenino de 71 años de edad, tabaquista severa, con un tumor pulmonar sin diagnóstico histológico previo. Con la paciente en posición supina, y bajo una sedación con midazolam y petidina IV, se realizó una broncoscopía con fibrobroncoscopio y una biopsia endobraquial. A continuación se llevó a cabo una marcación estereotáxica guiada por imágenes de tomografía axial computada (TAC), la craneotomía y la resección del tumor. El hombro izquierdo de la paciente fue elevado con compresas, y la cabeza se giró hacia la derecha a fin de mejorar el acceso a la fosa cerebral posterior. Para la craneotomía utilizamos midazolam-droperidol-fentanilo por vía IV más sevofluorano a bajas concentraciones >(0,5-1,5 por ciento) a través de una cánula nasal con oxígeno a 3 l/min. El monitoreo consistió en pulsioximetría, electrocardiografía, medición de la tensión arterial no invasiva ciclada en forma automática, frecuencia respiratoria y crapnografía. El tiempo total de cirugía fue de 285 minutos, siendo bien tolerada. La paciente fue transferida a la Sala de Cuidados Postanestésicos 50 minutos después de finalizada la operación, y dada de alta del hospital después de tres días.