Descompresión de fosa posterior sin duroplastia expansiva en adulto con malformación de Chiari tipo 1-siringomielia

Introducción: La malformación de Chiari tipo 1 incluye un grupo heterogéneo de malformaciones congénitas, caracterizadas por el descenso caudal del cerebelo a través del foramen magno. En un 30-70 % de los casos tiene siringomielia asociada. Existen controversias en torno a la técnica quirúrgica ideal. Objetivo: Presentar un caso de MC-1 asociada a siringomielia en el que no se aplica una duroplastia expansiva. Presentación de caso: Paciente femenina de 43 años, con antecedentes de hipertensión arterial. Acudió a consulta neuroquirúrgica por dolor cervical irradiado al miembro superior derecho. Al examen neurológico mostró signos de afectación de primera y segunda motoneurona. La resonancia magnética confirmó el diagnóstico de MC-1. Se intervino quirúrgicamente mediante descompresión de fosa posterior sin duroplastia expansiva. La paciente evolucionó sin complicaciones y egresó a las 48 horas. Durante el seguimiento mejoraron las manifestaciones parestésicas; sin embargo, el examen neurológico se mantuvo igual. A los seis meses, la resonancia magnética indicó una marcada disminución de la siringomielia y la reconformación de la cisterna magna. Hasta los 18 meses del tratamiento, los síntomas no habían empeorado y la capacidad funcional resultaba aceptable (Karnofsky 90/100). Conclusiones: La descompresión de fosa posterior sin duroplastia expansiva, seguida de re-permeabilización microquirúrgica del foramen de Magendie, tuvo resultados favorables en este caso.

Introduction: Chiari malformation type 1 includes a heterogeneous group of congenital malformations, characterized by caudal descent of the cerebellum through the foramen magnum. It has associated syringomyelia in 30-70% of cases. Controversies exist regarding the ideal surgical technique. Objective: To present a case of MC-1 associated with syringomyelia in which an expansive duroplasty is not applied. Case report: Female patient, 43 years old, with history of arterial hypertension. She went to the neurosurgical consultation for cervical pain radiating to the right upper limb. On neurological examination, she showed signs of first and second motor neuron involvement. MRI confirmed the diagnosis of MC-1. She underwent surgery by decompression of the posterior fossa without expansive duroplasty. The patient evolved without complications and she was discharged after 48 hours. During the follow-up, the paresthetic manifestations improved; however, the neurological examination remained the same. At six months, MRI indicated a marked decrease in syringomyelia and reshaping of the cisterna magna. Until 18 months after treatment, symptoms had not worsened and functional capacity was acceptable (Karnofsky 90/100). Conclusions: Posterior fossa decompression without expansive duroplasty, followed by microsurgical re-permeabilization of Magendie's foramen, had favorable results in our case.

Cerebral oxygenation assessed by near-infrared spectroscopy in the sitting and prone positions during posterior fossa surgery: a prospective, randomized clinical study

Abstract Objectives: Sitting position (SP) or prone position (PP) are used for posterior fossa surgery. The SP induced reduction in cerebral blood flow and cerebral oxygen saturation (rSO2) has been shown in shoulder surgeries, but there is not enough data in intracranial tumor surgery. Studies showed that PP is safe in terms of cerebral oxygen saturation in patients undergoing spinal surgery. Our hypothesis is that the SP may improve cerebral oxygenation in the patients with intracranial pathologies due to reduction in intracranial pressure. Therefore, we compared the effects of the SP and PP on rSO2 in patients undergoing posterior fossa tumor surgery. Methods: Data were collected patients undergoing posterior fossa surgery, 20 patients in SP compared to 21 patients in PP. The rSO2 was assessed using INVOS monitor. Heart rate (HR), mean arterial pressure (MAP), EtCO2, BIS, and bilateral rSO2 were recorded preoperatively, and at 5, 8, and 11 minutes after the intubation and every 3 minutes after patient positioning until the initial surgical incision. Results: Cerebral oxygenation slowly reduced in both the sitting and prone position patients following the positioning (p < 0.002), without any difference between the groups. The HR and MAP were lower in the sitting SP after positioning compared to the PP. Conclusion: Neurosurgery in the SP and PP is associated with slight reduction in cerebral oxygenation. We speculate that if we rise the lower limit of MAP, we might have showed the beneficial effect of the SP on rSO2.

Measurement of the magnetic resonance imaging of the area supratentorial and infratentorial mid-sagittal plane of the normal Tibetan adults / 解剖学报

[Abstract] Objective To explore the relationship between supratentorial area (STA), posterior fossa area (PFA) and intracranial area (ICA) of normal adult Tibetans with age and gender. Methods The subjects of this study were native Tibetan adults living in Lhasa. Totally 158 sample populations were between the ages of 20 and 59 years, with an average age (36. 60 ± 10. 75) years, including 64 males and 94 females. Siemens MAGNETOM ESSENZA 1. 5T magnetic resonance scanner was used to scan with 3D-fSPGR sequence, and the images obtained by scanning were stored in DICOM format and imported into 3D Medical medical image processing software, and region of interest was delineated by using the software’s own toolkit. STA, PFA and ICA were measured on T1WI mid-sagittal imaging, and the ratios of PFA / STA, STA / ICA and PFA / ICA were calculated. In order to eliminate the influence of individual differences in skull size on brain structure, this paper corrected the STA and PFA with the same level of ICA, and obtained the relativity of supratentorial area (RSTA) and relativity of posterior fossa area (RPFA). Results The STA was (127. 91 ± 9. 84) cm

Research Progress on the Application of Goel Technique in Craniovertebral Junction Anomalies / 中国医学科学院学报

Craniovertebral junction anomalies are a group of diseases characterized by the pathological changes of occipital bone,atlantoaxial bone,cerebellar tonsil,surrounding soft tissue,and nervous system,which are caused by a variety of factors.Chiari malformation is a common type of craniovertebral junction anomalies,the conventional surgical therapy of which is posterior fossa decompression.Currently,scholars represented by Goel have proposed a new theory on the classification,pathogenesis,and treatment of Chiari malformation based on posterior atlantoaxial fixation (Goel technique).This article introduces the progress in Goel technique,aiming to provide reference for the clinical work.

Surgical management of Dandy-Walker syndrome in infants and the literature review / 中国综合临床

Dandy-Walker syndrome is one of the posterior fossa malformations, which is easily confused with arachnoid cyst or cerebellar dysplasia in clinical practice, leading to misdiagnosis. Dandy-Walker syndrome is easy to be combined with hydrocephalus, resulting in increased intracranial pressure, increased head circumference, growth retardation, spastic hemiplegia and other manifestations, and can also be accompanied by other nervous system malformations. On February 27, 2021, a child with Dandy-Walker syndrome with growth retardation as the primary manifestation was admitted to Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine. After multiple surgical treatment, the child's hydrocephalus was significantly improved. Through the analysis of the clinical data of the child's operation and the treatment of complications, it is helpful to improve the clinicians' understanding of the surgical treatment of the disease.

Meningioma de la fosa posterior con hidrocefalia secundaria a resección quirúrgica / Posterior fossa meningioma with hydrocephalus after surgical resection

RESUMEN Los meningiomas de la fosa posterior representan el 10 % en relación con los otros sitios en los que pueden estar localizados. Estas lesiones pueden provocar compromiso de la circulación de líquido cerebroespinal. Se presentó el caso de una paciente de 67 años de edad con antecedentes previos de trastornos en la deambulación, se observó dificultad para caminar, en 15 días de evolución. Se realizó diagnóstico por tomografía de lesión ocupante de espacio localizada en fosa posterior. La paciente fue operada y secundariamente presentó hidrocefalia aguda, no comunicante, se le realizó derivación ventrículo-peritoneal. No existieron otras complicaciones asociadas a la intervención quirúrgica.

ABSTRACT Posterior fossa meningiomas represent 10% in relation to the other sites where they may be located. These lesions can compromise cerebrospinal fluid circulation. We present a 67-year-old female patient with a previous history of walking disorders, observing walking difficulty with 15 days of evolution. Diagnosis was made by a tomography of the space-occupying lesion located in the posterior fossa. The patient underwent surgery and subsequently developed acute non-communicating hydrocephalus, for which a ventricle-peritoneal shunt was performed. No other complications were associated with surgical intervention.

Diagnostic value of ultrasound in fetal posterior fossa anomalies at 11-13 + 6 gestational weeks / 中华超声影像学杂志

Objective:To explore the diagnostic value of ultrasound in posterior fossa anomalies (PFA) at 11-13 + 6 gestational weeks by measuring brainstem (BS), brainstem-to-occipital bone (BSOB) diameter and BS/BSOB ratio. Methods:A total of 209 normal fetuses (control group) were randomly selected from Beijing Obstetrics and Gynecology Hospital, Capital Medical University, between March 2018 and November 2021. Reference ranges for BS, BSOB diameter and BS/BSOB ratio were obtained on the mid-sagittal view of the fetal profile and the relationship of three parameters and crown-rump length (CRL) was investigated. The intra- and inter-observer reliabilities were determined by intraclass correlation coefficient (ICC) in 30 normal fetuses. Fourteen fetuses diagnosed with PFA in the same period including 10 cases of cystic posterior fossa malformations (cPFM) and 4 cases of open spine bifida (OSB) were retrospectively selected to compare BS, BSOB diameter and the BS/BSOB ratio with control group.Results:BS and BSOB diameters were successfully obtained in all control fetuses (100%), and the intra- and inter-observer reliabilities for BS and BSOB diameters were good (ICC=0.877, 0.846 and 0.939, 0.895). In the control group, BS and BSOB diameter linearly correlated with CRL ( r=0.867, 0.794; all P<0.001), while the BS/BSOB ratio was 0.75 (0.71, 0.79). There were significant differences of BSOB diameter and BS/BSOB ratio between control group and PFA group (all P<0.05). Except for one isolated vermian hypoplasia (VH), the BSOB diameters in 9 (90%) cases of cPFM were above the 95th percentile of the calculated normal range and were below the 5th percentile in 4(100%) cases of OSB.Except for one isolated VH, the BS/BSOB ratio in 9 (90%) cases of cPFM was below the 5th percentile of the calculated normal range. The BS/BSOB ratio in 4 (100%) cases of OSB was above the 95th percentile of the calculated normal range. Conclusions:The measurements of BS and BSOB diameter are feasible with good repeatability. Abnormal BSOB diameter and BS/BSOB ratio are suggestive for PFA. The posterior fossa of isolated VH can be normal in the first trimester.

The clinical effect of posterior fossa decompression combined with dural reconstruction in the treatment of Chiari malformation-Ⅰ complicated with syringomyelia / 中国医师进修杂志

Objective:To investigate the clinical effect of posterior fossa decompression combined with dural reconstruction in the treatment of Chiari malformation-Ⅰ(CM-Ⅰ) complicated with syringomyelia (SM).Methods:The clinical data of 50 patients with CM-Ⅰ complicated with SM who were treated in Yan′an University Xianyang Hospital from June 2019 to January 2021 were analyzed. They were divided into the study group (27 cases) and the control group (23 cases) according to the surgical methods. The former received posterior fossa decompression combined with dural reconstruction, while the latter received posterior fossa decompression alone. The clinical symptom improvement, neurological function, cerebrospinal fluid dynamics and syringomyelia changes were compared between the two groups before and after the surgery, and postoperative complications were compared.Results:The overall clinical symptom improvement rate between the two groups had no significant difference ( P> 0.05). After the surgery, the scores of pain, sensory disturbance, dyskinesia and ataxia in the study group were higher than those in the control group: (4.56 ± 0.35) points vs. (4.28 ± 0.43) points, (3.61 ± 0.82) points vs. (3.15 ± 0.73) points, (3.81 ± 0.44) points vs. (3.59 ± 0.50) points, (4.43 ± 0.41) points vs. (4.09 ± 0.53) points, there were statistical significant ( P<0.05). After the surgery, the cerebrospinal fluid stroke volume (SV) and mean flow (MF) in the study group were higher than those in the control group: (0.05 ± 0.02) ml vs. (0.04 ± 0.01) ml, (0.05 ± 0.01) ml/s vs. (0.04 ± 0.01) ml/s; the maximum peak flow velocity (V max) of the head and tail in the study group were lower than those in the control group: (3.14 ± 1.05) mm/s vs. (3.87 ± 1.13) mm/s, (5.56 ± 1.38) mm/s vs. (6.43 ± 1.22) mm/s, there were statistical significant ( P<0.05). There were no significant differences in the rate of reduction or disappearance of syringomyelia, the rate of no change and the rate of increase of syringomyelia after the surgery between the two groups ( P>0.05). There was no significant difference in the incidence of postoperative complications between the two groups ( P>0.05). Conclusions:Posterior fossa decompression combined with dural reconstruction in CM-Ⅰ complicated with SM can better improve cerebrospinal fluid dynamics, and promote the reduction of syringomyelia without increasing postoperative complications.

Meningiomas de fosa posterior: nomenclatura con orientación anatomo-quirúrgica y presentación de casos ilustrativos / Posterior fossa meningiomas: nomenclature with anatomical-surgical orientation and presentation of illustrative cases

Introducción: Los meningiomas de la fosa posterior representan el 20% de todos los meningiomas intracraneales. Cada subtipo tiene una base de implantación, abordaje quirúrgico y morbimortalidad postoperatoria muchas veces diferente. Advertimos que en reuniones científicas y publicaciones no se sigue una forma de clasificar uniforme, sencilla y clara con orientación netamente quirúrgica. Esto genera que el neurocirujano en formación no cuente con herramientas suficientes para la toma de decisiones. Objetivos: Proponer una clasificación sencilla de los meningiomas de la fosa posterior con un fundamento anatomo-quirúrgico y presentar casos ilustrativos de cada subtipo. Materiales y métodos: Se estableció una nomenclatura considerando reportes previos, el criterio anatómico y la experiencia quirúrgica de los autores. Se presentaron casos revisando las historias clínicas y los archivos de imágenes correspondientes a cada subtipo de la clasificación. Resultados: Representamos a la fosa posterior como un compartimento con 3 anillos: el superior se divide en medial, lateral-anterior y lateral-posterior; el medio se divide en 6 variantes: clivales puros, esfeno-petro-clivales, petrosos anteriores, petrosos posteriores y de la convexidad suboccipital medial y lateral; el inferior se divide en anterior, lateral derecho, lateral izquierdo y posterior. Conclusión: Los meningiomas del anillo superior pueden resolverse mediante una vía suboccipital medial o lateral; los del anillo medio tienen un espectro de opciones más diverso; los del anillo inferior -siguiendo el esquema de división en cuadrantes de un reloj- pueden resolverse por medio de un abordaje suboccipital medial o extremolatera

Introduction: Posterior fossa meningiomas represent 20% of all meningiomas, being each location associated with a specific approach, morbidity and mortality. The actual classifications are focus on the dural attachment, without associating the anatomical with the surgical aspects, useful to the young neurosurgeons for decision making. Objectives: To propose a classification of the posterior fossa meningiomas with an anatomical-surgical view including the presentation of cases. Materials and Methods: A nomenclature was established concerning previous reports, the anatomical criteria and the surgical experience of the authors. Cases were presented by reviewing the medical records corresponding to each subtype of the proposed classification. Results: We represent the posterior fossa as a 3 rings compartment: the upper one is divided into medial, anterior-lateral and posterior-lateral; the middle ring is divided into 6 variants: pure clival, spheno-petro-clival, anterior petrosal, posterior petrosal, and medial and lateral suboccipital convexity; the lower ring is divided into anterior, right lateral, left lateral, and posterior. Conclusion: Superior ring meningiomas can be resolved by a medial or lateral suboccipital approach; middle ring meningiomas have a more diverse spectrum of options; while meningiomas of the inferior ring - following the scheme of division into quadrants of a clock - can be resolved by means of a medial or extreme-lateral suboccipital approach.

Ependimomas intracraneales pediátricos: Si el objetivo es la curación, ¿cuál es el verdadero costo? / Pediatric Intracranial Ependymomas: If the Goal Is Cure, What Is the True Cost?

Introducción: Para caracterizar mejor la morbilidad neurológica después de una cirugía de resección máxima seguida de radioterapia en niños con ependimoma infratentorial, decidimos estudiar el estado neurológico prequirúrgico y compararlo con las evaluaciones postoperatorias a corto y largo plazo. Al mismo tiempo realizamos un estudio de sobrevida libre de progresión (SLP) tumoral para conocer qué factores tienen mayor impacto en el pronóstico de este tipo de lesiones. Métodos: Se realizó un estudio de cohorte retrospectivo donde se incluyeron todos los pacientes pediátricos con diagnóstico de ependimoma infratentorial. Se identificaron los distintos factores de riesgo y se observó cómo evolucionaron en el tiempo. Los pacientes se siguieron por un mínimo de 24 meses para el análisis de supervivencia. Resultados: Se analizaron 26 pacientes pediátricos con ependimomas de fosa posterior entre 2008-2019. Encontramos una diferencia estadísticamente significativa entre el FSS (Escala funcional neurológica) prequirúrgico y el FSS postoperatorio inmediato (p=0.03), sin embargo esta diferencia se pierde cuando comparamos el prequirúrgico con el FSS posterior al año (p=0.07).La exéresis total de la lesión tiene un efecto protector en la SLP tumoral (p=0.02), mientras que haber requerido más de 3 cirugías afecta negativamente la SLP tumoral (p=0.04), al igual que la localización lateralizada del tumor (p=0.04). Conclusión: La exéresis completa de los ependimomas de fosa posterior continúa siendo el factor pronóstico más importante para la sobrevida libre de progresión tumoral. El deterioro neurológico inmediato producido a causa del procedimiento quirúrgico parecería mejorar en la evaluación a largo plazo.

Introduction: To better characterize the neurological morbidity after maximal resection surgery followed by radiotherapy in children with infratentorial ependymoma, we decided to study the preoperative neurological status and compare it with short and long-term postoperative evaluations. At the same time, we conducted a tumor progression-free survival (PFS) study to find out which factors have the greatest impact on the prognosis of this type of injury. Methods: A retrospective cohort study was carried out in which all pediatric patients with a diagnosis of infratentorial ependymoma were included. The different risk factors were identified and it was observed how they evolved over time. Patients were followed for a minimum of 24 months for survival analysis. Results: 26 pediatric patients with posterior fossa ependymomas were analyzed between 2008-2019. We found a statistically significant difference between the presurgical FSS (Functional Status Scale) and the immediate postoperative FSS (p = 0.03), however this difference is lost when we compare the presurgical with the FSS after one year (p = 0.07).Total excision of the lesion has a protective effect on tumor PFS (p = 0.02), while having required more than 3 surgeries negatively affects tumor PFS (p = 0.04), as does the lateralized location of the tumor (p = 0.04). Conclusion: Complete excision of posterior fossa ependymomas continues to be the most important prognostic factor for tumor progression-free survival. The immediate neurological deterioration produced by the surgical procedure would appear to improve on the long-term evaluation

Linfoma difuso de células B grandes primario de clivus: Reporte de un caso

Resumen El clivus corresponde a una región de la fosa craneal posterior conformada por la unión del cuerpo del hueso esfenoidal y la porción basilar del hueso occipital, siendo sus lesiones poco frecuentes. Dentro de las lesiones clivales las más frecuentes son los cordomas (40%), condrosarcomas, adenomas ectópicos, linfomas, entre otros. Los linfomas no Hodgkin primario de hueso corresponden a una presentación extranodal, muy infrecuente en adultos, constituyendo sólo un 1% a 2% de estos en la base de cráneo. Se presentan principalmente con cefalea, síntomas B, diplopia y parestesias trigeminales. El origen primario clival es una manifestación aún más infrecuente, siendo su principal síntoma la cefalea. La sospecha debe ser alta requiriendo neuroimágenes, luego biopsia ya sea endoscópica o abierta. El manejo es con quimioterapia R-CHOP con un 67% de respuesta completa, 16% de detención de la progresión y 16% de progresión pese a tratamiento.

Abstract The clivus corresponds to a posterior cranial fossa region formed by the union of the body of the sphenoid bone and the basilar portion of the occipital bone, being its pathology very rare. Among the clival lesions, the most frequent are chordomas (40%), chondrosarcomas, ectopic adenomas, lymphomas, among others. Primary bone non-Hodgkin lymphomas correspond to an extranodal presentation, which is very infrequent in adults, while the skull base presentation corresponds only to 1% to 2%. They present mainly with headache, B symptoms, diplopia, and trigeminal paresthesia. The primary clival origin is an even more infrequent manifestation, with headache being its main symptom. The clinical suspicious must be high, requiring neuroimaging, then an endoscopic or open surgery biopsy. Management is standardized with R-CHOP chemotherapy with a 67% of complete response, 16% stop of progression and 16% progression despite treatment.

Efficacy of modified posterior fossa decompression in the treatment of Chiari type Ⅰ malformation with the neuroendoscope / 西安交通大学学报(医学版)

【Objective】 To investigate the clinical efficacy of modified posterior fossa decompression in treating Chiari type I malformation under the neuroendoscope. 【Methods】 We made a retrospective analysis of the clinical data of 63 patients with Chiari type I malformation treated at the Neurosurgery Department of The First Affiliated Hospital of Xi’an Jiaotong University from January 2015 to December 2019. Of the patients, 28 ones underwent modified posterior fossa decompression assisted with neuroendoscopy (observation group) while 35 received posterior fossa decompression with duraplasty (control group). Tator grading, syringomyelia improvement and complications were compared between the two groups to evaluate the postoperative efficacy. 【Results】 The operations were successful in all the 63 patients and no death or severe neurological dysfunction was observed. The efficacy rate was 78.6% in the observation group and 54.3% in the control group, with significant difference (P0.05). 【Conclusion】 Modified posterior fossa decompression assisted with neuroendoscope is a safe and effective treatment for Chiari type Ⅰ malformation. Intraoperative dural watertight suture and dural-muscle suspension can help reduce the occurrence of subcutaneous effusion.

Case report of bacterial meningitis complicated with posterior fossa subdural empyema in a newborn / 中华实用儿科临床杂志

The clinical data of a case of neonatal bacterial meningitis complicated with posterior fossa subdural empyema in the West China Second University Hospital in December 2019 were retrospectively analyzed.The 3-day-old male newborn was admitted for jaundice with decreased intake for 1 day.Examinations on admission showed increased C-reactive protein.The count of karyocytes in cerebrospinal fluid (CSF) significantly increased, which were mainly neutrophils, and pyocytes could be found.The protein content in CSF increased, while that of glucose decreased.Both CSF culture and blood culture detected the presence of Escherichia coli.Enhanced magnetic resonance imaging (MRI) of the head indicated large abnormal signals in bilateral occipital extra-cerebellar spaces.T1-weighted images presented mixed low and high signals, and T2-weighted images presented high signals, and marginal enhancement was observed after enhancement.After 6 weeks of antibiotic treatment using Meropenem combined with Ceftazidime, the CSF index of the newborn patient returned to normal, and the subdural empyema of the posterior fossae subsided.Bacterial meningitis complicated with subdural empyema of posterior fossa is a rare and critical disease of the central nervous system.It is easily misdiagnosed due to the atypical clinical manifestations and early imaging features.The disease requires an adequate course of anti-infective treatment.Surgical removal of the empyema should be performed if the anti-infective treatment is unresponsive.

Quantitative evaluation of normal fetal posterior fossa anatomy using transabdominal three-dimensional ultrasound / 中华超声影像学杂志

Objective:To analyze the consistency and repeatability for quantitative evaluation of normal fetal posterior fossa anatomy using transabdominal three-dimensional ultrasound, and assess the clinical value.Methods:The midsagittal planes of fetal brain from 127 normal singleton fetuses with 22-34 weeks of gestation were obtained using transabdominal three-dimensional ultrasound between May, 2020 and May, 2021. The quantitative three-dimensional indicators were measured by two observers, then were measured twice by one of the two observers. The double blind was performed in course of measuring procedures. The intraobserver and interobserver agreements were evaluated. The relationships between three-dimensional indicators and gestational age were analyzed.Results:The quantitative three-dimensional indicators expressing the size of vermis, including area, perimeter, suprainferior diameter and anteroposterior diameter, had positive correlations with advanced gestational age ( r=0.934, 0.936, 0.920, 0.879; all P<0.001). The intra- and interobserver reproducibilities of measurements were very good with all intraclass correlation coefficients >0.80 (all P<0.001). Brainstem-vermis (BV) angle and Brainstem-tentorium (BT) angle had negative and positive correlations with advanced gestational age respectively ( r=-0.317, 0.366; both P<0.001). The intra-and interobserver reproducibilities of measurements were moderate or poor. Conclusions:The quantitative three-dimensional indicators describing the size of vermis are worthy of clinical application for evaluation of fetal posterior fossa owing to the excellent reproducibility and simple and feasible method of measurement. BV angle and BT angle are not applicable for junior physicians due to the poor reproducibility of measurement.

Posición semisentada en neurocirugía. Nota técnica y presentación de casos ilustrativos / Semi-sitting position in neurosurgery. Technical note and illustrative case presentation

Introducción: En las últimas décadas el uso de la posición sentada ha disminuido en frecuencia a causa de 2 complicaciones mayores: el embolismo aéreo venoso y la hipotensión intraoperatoria. Sin embargo es innegable que la posición sentada ofrece una serie de ventajas al neurocirujano, el anestesiólogo y al electrofisiólogo. Materiales y métodos: Estudio retrospectivo de pacientes operados en dos instituciones de Tucumán, entre enero de 2015 y diciembre de 2019. Resultados: Se operaron un total de 119 pacientes en posición sentada por vía posterior. Conclusión: Se presentó la técnica de posición semisentada paso a paso y consejos específicos. Se ilustró la utilidad de la misma mediante la presentación de casos representativos

Introduction: In the last decades, the use of the sitting position has been abandoned due to 2 major complications: venous air embolism and intraoperative hypotension. However, it is undeniable that the sitting position offers a series of advantages to the neurosurgeon, the anesthesiologist and the electrophysiologist. Materials and methods: Retrospective study of patients operated at two institutions in Tucumán, between January 2015 and December 2019. Results: A total of 119 patients were operated in a sitting position and posterior approach. Conclusion: The sitting position technique was presented step by step in detail, with the key steps and a series of tricks. The usefulness of the position was illustrated by presenting representative cases

Hemifacial Spasm Associated with Chiari Type I Malformation: Surgical Considerations and Case Report

Hemifacial spasm (HS) is a movement disorder characterized by paroxysmal and irregular contractions of the muscles innervated by the facial nerve. Chiari malformation type I (CM I) is a congenital disease characterized by caudal migration of the cerebellar tonsils, and surgical decompression of foramen magnum structures has been used for treatment. The association of HS with CM I is rare, and its pathophysiology and therapeutics are speculative. There are only a few cases reported in the literature concerning this association. The decompression of the posterior fossa for the treatment of CM I has been reported to relieve the symptoms of HS, suggesting a relation between these diseases. However, the possible complications of posterior fossa surgery cannot be underrated. We report the case of a 66-year-old patient, in ambulatory follow-up due to right HS, no longer responding to botulinum toxin treatment. Magnetic resonance imaging (MRI) of the skull revealed compression of the facial nerve and CM I. The patient underwent surgery for HS by neurovascular microdecompression of the facial nerve via right lateral suboccipital craniectomy, but presented significant clinical worsening in the postoperative period even though the cerebellum edema related to surgical manipulation was mild. Due to the clinical worsening, the patient underwent a median suboccipital craniectomy with decompression of the foramenmagnum structures. After this second surgery, the patient had progressive improvement and was discharged from the hospital for ambulatory care.

An analysis of factors determining the requirement of ventriculoperitoneal shunt surgery in the children suffering from posterior fossa tumour: a single centre retrospective review

Background: Hydrocephalus is a relatively common occurrence in a children suffering from the posterior fossa tumour (PFTm). However, there is a divided opinion regarding the ventriculoperitoneal shunt (VPS) surgery before the posterior fossa tumour resection in a child. For the better clinical outcome, we should be able to predict which patient will require VPS following the resection of PFTm. Purpose of our retrospective analysis is to analyse various factors that predicts the necessity of VPS following PFTm resection.Methods: A consecutive series of twenty-six patients who underwent PFTm resection without undergoing VPS preoperatively are analysed in our series.Results: In our series, we found that the younger age at presentation, incomplete tumour resection, longer period of artificial ventilatory support, insertion of external ventricular drain (EVD) and its duration during the postoperative period correlate the necessity of VPS following PFTm resection. However, the severity of hydrocephalus prior to tumor surgery, tumour size, anatomical location of the tumour, tumour dissemination, use of Dural grafts during closure and histopathological type do not predict the requirement of the VPS following PFTm.Conclusions: Patients who are younger at diagnosis should be treated with utmost importance. Gross total resection should be the goal. Factors which predict the likelihood of the EVD which parallels the likelihood of postresection hydrocephalus must be prevented for the better clinical outcome.

Enfoque diagnóstico del síndrome vestibular agudo en urgencias / Integral approach of acute vestibular síndrome

RESUMEN El vértigo se define como una sensación rotacional de movimiento y es uno de los principales motivos de consulta en urgencias. Aproximadamente entre el 5 y 7% de los pacientes que asisten a consulta de Medicina General han presentado esta afección en el último año. Por este motivo, es necesario tener una adecuada orientación de los casos que permita identificar su causa y diferenciar entre la patología central y periférica lo que permitirá abordar los pacientes de una manera adecuada, que permita distinguir aquellos que requieran hospitalización para estudios complementarios de los que pueden ser manejados ambulatoriamente. A continuación, revisaremos los principales síntomas clínicos, las pruebas semiológicas más utilizadas y las etiologías más relevantes para describir un abordaje sencillo de este síndrome.

SUMMARY Vertigo is defined as a sensation of rotation or imbalance and is a common complain for emergency room consultation. Approximately between 5% and 7% of patients who consulted their general physician in the last year have presented vertigo. Therefore, it is essential to have an adequate understanding of this disease to properly distinguish between the principal causes as it orients proper treatment. This article is a review of the main symptoms, frequently used clinical exams and relevant etiologies, in order to provide a simple orientation to general practitioners.

Microneurosurgical aspects in the management of posterior cranial fossa epidermoids: experience of 24 cases

Background: There is considerable debate in the surgical management of epidermoid cyst, whether gross total or subtotal resection yields better long term outcomes. We present our institutional experience in evaluating the clinical presentation, diagnosis, and surgical strategy and extent of resection in the management of posterior cranial fossa epidermoid cyst.Methods: A retrospective review of 24 patients diagnosed with posterior cranial fossa epidermoid tumors surgically treated at the institution between January 2010 and July 2019.Results: A total of 24 patients who underwent surgery for intracranial epidermoid lesions were identified. Of these 13 were in the Cerebellopontine angle region, eight were in the fourth ventricle, and three in lateral cerebellar convexity. The mean duration from onset of symptoms to surgery was 1.6 years. Cranial nerve dysfunction was noted in 73% of patients preoperatively, most of them being the CPA epidermoids. Total removal was achieved in 16 patients, near-total resection in 6 patients, and subtotal removal in 2 patients. Three patients developed recurrence radiologically of them only one patient became symptomatic. The mean duration of follow-up was 3.8 years. The content of the tumor was pearly white material in all cases. Complications noted in the present series were not related to the completeness of excision. Mortality was noted in one patient.Conclusions: The present study highlights various precautions to be taken intraoperatively in the prevention of development of aseptic meningitis and concludes that total removal of epidermoids does not result in significantly increased morbidity and mortality and should be the goal of surgical treatment. However, near/subtotal resection of lesions that are densely adherent to neurovascular structures is justified, as there is no significant difference in the rate of recurrence. An endoscope can be used to assess the completeness of surgery.

Postoperative posterior fossa pseudomeningocele: risk factors and management strategies

Background: Pseudomeningocele is a considerable morbidity after posterior fossa surgery. Its incidence and optimal management strategies are quite unclear. Hence the objective of this study is to define the risk factors and evaluate the management strategies and to study the incidence and morbidity of postoperative posterior fossa pseudomeningocele.Methods: A retrospective study of 33 patients undergone posterior fossa surgery for variety of diseases in the department of neurosurgery, Saveetha Medical College and Hospital from January 2015 to December 2018 with emphasis on incidence of pseudomeningocele,its morbidity and treatment strategies.Results: Out of 33 posterior fossa surgeries performed, 9 developed pseudomeningocele. Hence the incidence of pseudomeningocele in hospital is 27.27%. Out of 9 patients who developed pseudomeningocele, 6 patients were symptomatic, and aspiration was done to 5 patients and one patient underwent resurgery. That one patient underwent subgaleal-peritoneal shunt, excision of recurrent tumor was performed after which the symptoms subsided.Conclusions: Psudomeningocele is a well-known complication of posterior fossa surgery. The risk factors for pseudomeningocele formation after posterior fossa surgery has been evaluated. Age, sex and type of surgery are found to be a risk factors in our study. Conservative management is effective in most cases to reduce the symptoms. Surgical intervention is advocated, only when conservative treatment fails. Preventive measures like careful perioperative planning, strict adherence to aseptic techniques, usage of autologous pericranium with dural sealant augmentation, polyethylene glycol hydrogel dural sealant can be adopted.