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OBJECTIVE: In the present study an attempt was made to quantify and characterise the changes in the intracranial pressure (ICP) waveform over the wide pressure range covered during infusion studies by means of the central tendency measure (CTM). CTM is a non-linear approach using continuous chaotic modelling that summarises the degree of variability in a signal. METHODS: CTM of the ICP wave in the lumbar subarachnoid space was analysed in 77 infusion studies performed in patients with idiopathic and secondary forms of normal pressure hydrocephalus (median age 74 years, range 22-88). Four artefact-free epochs were selected during the baseline, infusion, plateau and relaxation stages of every infusion study. The average pressure, pulse amplitude and CTM were determined for each epoch. Correlations among these parameters were explored. RESULTS: CTM of the ICP waveform decreases, i.e. variability increases, as infusion studies progress from baseline pressure to the plateau stage. Significant correlations were found during all phases of infusion testing, except at baseline, between CTM and pressure, CTM and amplitude and pressure and amplitude. Partial correlations emphasised the relationship between CTM and amplitude. When pulse amplitude is held constant, CTM and the pressure range do not correlate. CONCLUSIONS: Volume loading leads to increased variability of the ICP signal measured by means of CTM. This finding summarises numerically the long-established phenomenon of increasing amplitude and rounding of ICP pulses associated with ICP elevation during infusion studies. CTM could be a suitable approach to quantify and characterise the pulsatile nature of the ICP wave.

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BACKGROUND: The complexity of the intracranial pressure (ICP) signal decreases with intracranial hypertension in children with acute brain injury as well as during infusion studies in adults with hydrocephalus. In this study we have analysed the pressure signal obtained in the lumbar subarachnoid space during infusion testing. The pulse amplitude rises when the ICP is increased by additional external volume. Our objective was to determine the relative influence of the pressure range and pulse amplitude on the loss of complexity observed during infusion-related intracranial hypertension. MATERIALS AND METHODS: The Lempel-Ziv (LZ) complexity of the cerebrospinal fluid pressure (CSFP) signal was analysed in 52 infusion studies performed in patients with normal pressure hydrocephalus (median age 71 years, IQR: 60-78). Four sequences during the baseline, infusion, steady plateau and recovery periods of each infusion study were selected. The mean values of the CSFP (mCSFP), pulse amplitude and LZ complexity in every sequence were measured. Correlations between LZ complexity and CSFP parameters were explored. RESULTS: Significant inverse correlations were found among LZ complexity, pulse amplitude and mCSFP during all periods of infusion testing, except at baseline. Partial correlation analysis controlling the effect of mCSFP emphasised the relationship between pulse amplitude and LZ complexity. When pulse amplitude is held constant the partial correlation between LZ complexity and mCSFP is not significant. CONCLUSIONS: The pulse amplitude of the CSFP signal seems to be a major determinant of the waveform complexity.

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An actualized revision of the most important aspects of aneurismal subarachnoid hemorrhage is presented from the guidelines previously published by the group of study of cerebrovascular pathology of the Spanish Society of Neurosurgery. The proposed recommendations should be considered as a general guide for the management of this pathological condition. However, they can be modified, even in a significant manner according to the circumstances relating each clinical case and the variations in the therapeutic and diagnostic procedures available in the center attending each patient.

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Se realiza una actualización sobre los aspectos másimportantes de la hemorragia subaracnoidea aneurismáticarespecto a las guías previamente publicadaspor el grupo de trabajo de la SENEC. Las recomendacionespropuestas deben considerarse como una guíageneral de manejo de esta patología. Sin embargo,pueden ser modificadas, incluso de manera significativapor las circunstancias propias de cada casoclínico, o las variaciones en los recursos diagnósticosy terapéuticos del centro hospitalario que reciba alpaciente (AU)

An actualized revision of the most important aspectsof aneurismal subarachnoid hemorrhage is presentedfrom the guidelines previously published by the groupof study of cerebrovascular pathology of the SpanishSociety of Neurosurgery. The proposed recommendationsshould be considered as a general guide for themanagement of this pathological condition. However,they can be modified, even in a significant manneraccording to the circumstances relating each clinicalcase and the variations in the therapeutic and diagnosticprocedures available in the center attending eachpatient (AU)

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BACKGROUND. The Spanish neurosurgical society created a multicentre data base on spontaneous SAH to analyze the real problematic of this disease in our country. This paper focuses on the group of patients with idiopathic SAH (ISAH). METHODS. 16 participant hospitals collect their spontaneous SAH cases in a common data base shared in the internet through a secured web page, considering clinical, radiological, evolution and outcome variables. The 220 ISAH cases collected from November 2004 to November 2007 were statistically analyzed as a whole and divided into 3 subgroups depending on the CT blood pattern (aneurysmal, perimesencephalic, or normal). RESULTS. The 220 ISAH patients constitute 19% of all 1149 spontaneous SAH collected in the study period. In 46,8% of ISAH the blood CT pattern was aneurysmal, which was related to older age, worse clinical condition, higher Fisher grade, more hydrocephalus and worse outcome, compared to perimesencephalic (42.7%) or normal CT (10.4%) pattern. Once surpassed the acute phase, outcome of ISAH patients is similarly good in all 3 ISAH subgroups, significantly better as a whole compared to aneurysmal SAH patients. The only variable related to outcome in ISAH after a logistic regression analysis was the admission clinical grade. CONCLUSIONS. ISAH percentage of spontaneous SAH is diminishing in Spain. Classification of ISAH cases depending on the blood CT pattern is important to differentiate higher risk groups although complications are not negligible in any of the ISAH subgroups. Neurological status on admission is the single most valuable prognostic factor for outcome in ISAH patients.

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Background. The Spanish neurosurgical society created a multicentre data base on spontaneous SAH to analyze the real problematic of this disease in our country. This paper focuses on the group of patients with idiopathic SAH (ISAH).Methods. 16 participant hospitals collect their spontaneous SAH cases in a common data base shared in the internet through a secured web page, considering clinical, radiological, evolution and outcome variables. The 220 ISAH cases collected from November 2004 to November 2007 were statistically analyzed as a whole and divided into 3 subgroups depending on the CT bloodpattern (aneurysmal, perimesencephalic, or normal).Results. The 220 ISAH patients constitute 19% of all 1149 spontaneous SAH collected in the study period. In 46,8% of ISAH the blood CT pattern was aneurysmal, which was related to older age, worse clinical condition, higher Fisher grade, more hydrocephalus and worse outcome, compared to perimesencephalic (42,7%) or normal CT (10,4%) pattern. Once surpassed the acute phase, outcome of ISAH patients is similarly good in all 3 ISAH subgroups, significantly better as a whole compared to aneurysmal SAH patients. The only variable related to outcome in ISAH after a logistic regression analysis was the admission clinical grade. Conclusions. ISAH percentage of spontaneous SAHis diminishing in Spain. Classification of ISAH cases depending on the blood CT pattern is important to differentiate higher risk groups although complications are not negligible in any of the ISAH subgroups. Neurological status on admission is the single most valuable prognostic factor for outcome in ISAH patients (AU)

Propósito. El grupo de trabajo de Patología Vascular de la SENEC desarrolló y mantiene abierta una base de datos multicéntrica que recoge los casos de hemorragia subaracnoidea espontánea. Con esta base se pretende analizar la problemática real que representa esta patología en nuestro medio. Este trabajo se centra en el estudio del grupo de pacientes de la base que presentaron HSA idiopática o de origen no aclarado (HSAI).Materiales y métodos. La base de datos recoge los casos de HSA espontánea de 16 hospitales españoles a través de una página Web compartida en Internet de forma segura. Se consideran variables epidemiológicas ,clínicas y radiológicas, así como la aparición de complicaciones y la evolución de los pacientes. Entre Noviembre de 2004 y Noviembre de 2007 se recogieron 220 pacientes con HSA idiopática. Este grupo se ha analizado estadísticamente de forma global y subdividido en 3 grupos de acuerdo con el patrón TC de sangrado inicial (de tipo aneurismático, perimesencefálico o TCnormal). Resultados. Los 220 pacientes con HSAI representan el 19% del total de 1.149 pacientes con HSA recogidos en la base de datos en el mismo periodo. El 46,8% de los casos de HSAI presentaron patrón de sangrado aneurismático en TC, hecho que se correlacionó con mayor edad, peor condición clínica al ingreso, mayor grado Fisher de sangrado, más frecuencia de hidrocefalia y peor evolución, comparados con los casos de HSAI con sangrado en TC del tipo perimesencefálico (42,7%) o con TC normal (10,4%).Una vez superada la fase aguda, e independientemente del tipo de sangrado inicial, la evolución de los pacientes con HSAI es globalmente buena y significativamente mejor que la de los pacientes con HSA aneurismática. La única variable con valor pronóstico en los casos de HSAI, tras realizar un análisis de (..) (AU)

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BACKGROUND: There is general consensus that a successful endoscopic third ventriculostomy is usually followed by a decrease of ventricular size without reaching their normal size. This study was performed to determine how the change related to clinical outcome, how it developed chronologically and whether the change in ventricular size was different in acute and chronic forms of hydrocephalus. METHOD: Fifty-five of 74 patients who had undergone endoscopic third ventriculostomy during the period 1997-2004 were selected by the criterion that they had both pre-operative and post-operative films and no neurosurgical manoeuvre other than a surgically successful endoscopic third ventriculostomy in the time span between both radiological studies. Ventricular size was measured with the Evans index, third ventricle index, cella media index and ventricular score. Median age was 51 years (interquartile range, 27-65 years). RESULTS: The change in ventricular size detected shortly after surgery is related to clinical outcome for all ventricular ratios, except the cella media index (p = 0.08). When third ventriculostomy is clinically successful, there is a gradual decrease of ventricular size over a period of more than three months (p < 0.0001 for all ventricular ratios). The reduction is more prominent in acute hydrocephalus than in chronic forms for all ventricular ratios, except the Evans index (p = 0.12). The third ventricle exhibits the greatest reduction (25% with a 95% confidence interval: 15.4-34.5) and determines a different pattern of change in ventricular size after endoscopic third ventriculostomy between acute and chronic hydrocephalus. CONCLUSIONS: A decrease of the ventricular size detected soon after endoscopic third ventriculostomy is associated with a satisfactory clinical outcome. This response continues during the first few months after surgery. The reduction is more prominent in acute forms of hydrocephalus.

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OBJECTIVE: The aim of this study was to build a preoperative predictive system which could provide reliable information about: 1 degrees which skull base meningiomas can be total or partially removed, and 2 degrees their surgical outcome. METHOD: Patient histories and imaging data were reviewed retrospectively from 85 consecutive skull base meningiomas patients who underwent surgery from 1990 and 2002. From the preoperative data, nine variables were selected for conventional statistical analysis as regards their relationship with: 1 degrees total vs partial tumor resection and 2 degrees with patients outcome according to the degree of tumour removal. RESULTS: From the nine variables analysed only two had a statistical association with the type of tumour resection performed (total vs partial) and the patient outcome: 1) arteries encasement and 2) cranial nerves involvement. Upon correlating these two variables with the type of tumour resection performed (total vs partial) and with the Karnofsky'scale to evaluate patients surgical outcome, the following grading groups were identified: Grade I: skull base meningiomas which did not involve cranial nerves or artery or only encased one artery or one cranial nerve. In these cases the incidence of gross tumour resection was 98.3% (p< 0.0001) and the perspective to reach 70 points in the Karnofsky'scale was of 96.5% ( p=0.001). Grade II: skull base meningiomas which involved one cranial nerve and encased, at least, two main cerebral arteries. In these cases, the frequency of total resection, decreased to 83.3% (p<0.0001) and the probability to reach 70 points in the Karnofsky'scale was 70.6% (p=0.001). Grade III: skull base meningiomas which involved two or more cranial nerves and encased several arteries In this group, the frequency of a total resection was of 42.9% (p<0.0001) and the probability of reaching 70 points in the Karnofsky'scale was only 60% (p=0.001). CONCLUSIONS: We propose a preoperative grading system for skull base meningiomas that helps predicting both whether total or partial tumor removal will be achieved during surgery and the immediate postsurgical outcome of the patient. In applying this predictive system we will be able to reduce surgical morbidity, to advance the possibility of a radiosurgical treatment and give a more precise information to the patients and their families about our surgical decision-making process.

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Objetivo. Encontrar un sistema predictivo que basándose únicamente en datos preoperatorios nos oriente, con fiabilidad, sobre : 1° qué meningiomas dela base de cráneo pueden ser extirpados total o parcialmente y 2° cuál es su pronóstico postquirúrgico. Métodos. Se ha revisado de forma retrospectiva, las historias clínicas e iconografías de 85 pacientes, con meningiomas de la base de cráneo, intervenidos entre1990 al 2002. De ellas se han tomado nueve variables que han sido tratadas estadísticamente, mediante un test estándar, para correlacionarlas con: 1° resección total o parcial del tumor (Simpson, 5 grados) y 2° conocido el mencionado grado de resección total o parcial, éste se correlacionó con el pronóstico funcional postoperatorio del paciente (Karnofsky).Resultados. De las variables preoperatorios analizadas, solo dos demostraron tener una asociación significativa con la extirpación total o parcial del tumor, así como con el pronóstico postquirúrgico del paciente. Dichas variables fueron: a) las arterias englobadas por el tumor (p = 0.001) y b) la afectación de pares craneales(p< 0.0001). Seguidamente, se conjugaron las diversas posibilidades de cada una de ellas para conocer el grado de extirpación tumoral (total o parcial). Para predecir el pronóstico funcional postoperatorio del enfermo, se relacionó la extirpación total o parcial con la escala de Karnofsky. De ambos análisis, grado de extirpación y pronóstico, se obtuvo el siguiente sistema de gradación: Grado I: meningiomas, de la base de cráneo, que no afectan a pares craneales ni engloban arterias o bien solamente afectan a un par craneal o engloban sólo una arteria. En ellos las posibilidades de extirpación total se encuentran en un 98,3% (p<0.0001) y las perspectivas de alcanzar 70 puntos en la escala de Karnofsky son de un 96,5%.Grado II: meningiomas que afectan a un par craneal e incluyen dos o más arterias. La extirpación total en estos casos disminuye al 83,3% (p< 0.0001) y las perspectivas de alcanzar 70 puntos en la escala de Karnofsky descienden a un 70,6%.Grado III: meningiomas que afectan dos o más pares craneales e incluyen varias arterias. En este grupo, las posibilidades de una extirpación total son de un 42,9% (p<0.0001) con las perspectivas de alcanzarlos 70 puntos en la escala de Karnofsky en sólo el 60%.Conclusiones. El sistema de gradación que se propone permite, en los casos de meningiomas de la base de cráneo: 1° predecir las posibilidades de una extirpación total o parcial y 2° conocer el pronóstico quirúrgico delos pacientes en cada grupo. Aplicando este sistema podremos reducir nuestra morbilidad quirúrgica, anticiparla necesidad de una terapia con radiocirugía y dar una información, más precisa, al paciente y familiares sobre nuestras propuestas quirúrgicas

Objective. The aim of this study was to build a preoperative predictive system which could provide reliable information about: 1° which skull base meningiomas can be total or partially removed, and 2°their surgical outcome. Method. Patient histories and imaging data were reviewed retrospectively from 85 consecutive skull base meningiomas patients who underwent surgery from1990 and 2002. From the preoperative data, nine variables were selected for conventional statistical analysis as regards their relationship with: 1° total vs partial tumor resection and 2° with patients outcome according to the degree of tumour removal. Results. From the nine variables analysed only two had a statistical association with the type of tumour resection performed (total vs partial) and the patient outcome: 1) arteries encasement and 2) cranial nerves involvement. Upon correlating these two variables with the type of tumour resection performed (total vs partial)and with the Karnofsky'scale to evaluate patients surgical outcome, the following grading groups were identified: Grade I: skull base meningiomas which did not involve cranial nerves or artery or only encased one artery or one cranial nerve. In these cases the incidence of gross tumour resection was 98,3% (p<0.0001) and the perspective to reach 70 points in the Karnofsky'scale was of 96,5% ( p= 0.001).Grade II: skull base meningiomas which involved one cranial nerve and encased, at least, two main cerebral arteries. In these cases, the frequency of total resection, decreased to 83,3% (p<0.0001) and the probability to reach 70 points in the Karnofsky'scale was 70,6%(p=0.001).Grade III: skull base meningiomas which involved two or more cranial nerves and encased several arteries In this group, the frequency of a total resection was of42,9% (p<0.0001) and the probability of reaching 70points in the Karnofsky'scale was only 60% (p= 0.001).Conclusions. We propose a preoperative grading system for skull base meningiomas that helps predicting both whether total or partial tumor removal will be achieved during surgery and the immediate postsurgical outcome of the patient. In applying this predictive system we will be able to reduce surgical morbidity, to advance the possibility of a radiosurgical treatment and give a more precise information to the patients and their families about our surgical decision-making process

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BACKGROUND: Endoscopic third ventriculostomy (ETV) has gained acceptance as the treatment of choice for noncommunicating hydrocephalus despite a relatively high failure rate and a higher surgical risk than the placement of a shunt. The benefits of shunt independence overcome both drawbacks. This argument also serves to consider candidates for ETV patients with a poor chance of success, a fact which may to a certain degree explain failure rates higher than 20% in most unselected series of patients with noncommunicating hydrocephalus. METHOD: From 1997 to 2003 sixty-six patients with suspected noncommunicating hydrocephalus were treated with ETV. Male and female patients were equally distributed. It is an adult-based series (median age 53 years). The etiology of hydrocephalus was a space-occupying lesion in 39 patients (59%) and primary aqueductal stenosis in 27 (41%). Forty-seven patients presented an acute form of hydrocephalus (71%), the remainder presented a chronic form of hydrocephalus. The morbidity and outcome of the procedure were reviewed. Criteria for success was shunt independence and failure was considered when any surgical manoeuvre was further required for the treatment of hydrocephalus. The outcome was evaluated using the Kaplan-Meier survival method. FINDINGS: The probability of remaining with a functioning ETV at 5.7 years (mean follow-up period) is 71.6% (95% confidence interval: 60.5-82.8). Failure occurred in 18 patients (27.3%). If failure occurs, there is a cumulative probability of 90% (95% confidence interval: 84-97) that the failure declares itself during the first 16 days after surgery. There were transient complications in five patients (7.5%), permanent in one (1.5%) and no mortality related to the procedure. CONCLUSIONS: ETV had a 5-year success rate of 71.6% with a low rate of permanent complications. When ETV is successful, the result tends to hold up over time. Delayed failure is a rare event.

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OBJECTIVE: To establish a more accurate indication for endoscopic third ventriculostomy (ETV) in patients with noncommunicating hydrocephalus through the analysis of the evolution of postoperative mean intracranial pressure (ICPM). METHOD: Intracranial pressure (ICP) was recorded overnight during 8-hour periods with an intraventricular probe. A personal computer connected to the ICP monitor minutely recorded the values of ICP. Twenty-four patients were monitored from day 1 to day 3 after ETV. The evolution of ICPM was analysed with an ANOVA test for repeated measures. The relevance of different factors (age, etiology, size of the lesion leading to hydrocephalus, clinical course and outcome) on the evolution of ICPM was explored with a two-factor ANOVA. RESULTS: ICPM progressively decreased from day 1 to day 3 after ETV (p = 0.03). ICPM on the first postoperative day was 15.81 +/- 2.04 mm Hg (mean +/- standard error) and 13.43 +/- 1.44 mm Hg on the third postoperative day. Different patterns in the evolution of ICPM have been detected according to the age of the patient and the clinical course of hydrocephalus. CONCLUSION: ICPM progressively decreases after ETV. This pattern is not constant. It has been clearly detected in children and in acute forms of hydrocephalus.

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INTRODUCTION: Endoscopic third ventriculostomy is the treatment of choice for non communicating hydrocephalus at our institution. Several factors have been associated with failure of endoscopic third ventriculostomy. The goals of the study have been to evaluate the outcome, the influence of factors theoretically prone to failure of ventriculostomy and the evolution of ventricular size. MATERIAL AND METHODS: Fifty-six patients (mean age 48.5 yrs) treated with an endoscopic third ventriculostomy during the period 1997-2002 were analysed retrospectively. Hydrocephalus was classified as acute (68%) and chronic forms. Etiology was classified in space-occupying lesions (59%), primary aqueductal stenosis (34%) and Chiari malformation (7%). The presence of the following factors theoretically prone to failure was considered: age below one year, history of mielomeningocele, cerebrospinal fluid (CSF) infection, intracranial haemorrhage, radiotherapy, craniotomy and previous treatment of hydrocephalus with a shunt. Ventricular size was measured linearly with four ventricular index pre- and postoperatively. RESULTS: The global success rate was 71.4% (mean follow-up 26 months). Endoscopic third ventriculostomy for hydrocephalus secondary to cerebral metastases obstructing CSF pathways was associated with a higher risk of failure (p=0.006). None of the risk factors considered was associated with a higher risk of failure. The evolution of the ventricular size measured with linear methods is associated with outcome. Evans ratio, third ventricle index, cella media index and ventricular score decreased in patients whose outcome is satisfactory and increased in those cases deemed clinical failures (p< 0.05). CONCLUSION: The risk of failure increases in patients with cerebral metastases close to CSF pathways, likely due to the concurrence of mechanisms other than obstruction. Changes in ventricular size are associated with outcome.

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INTRODUCTION: Hydrocephalus, cerebrospinal fluid (CSF) leak, pseudomeningocele and CSF infection are potential complications related to surgical treatment of posterior fossa tumors. The objectives of this study were to review the incidence of such complications and to identify contributing factors related to them. MATERIAL AND METHODS: This study is based on a retrospective review of the medical records of 71 consecutive patients who underwent posterior fossa surgery for a tumor between the period January 1997 and December 2001. Postoperative hydrocephalus was defined as enlargement of the ventricles and the subsequent clinical worsening requiring surgical treatment. Criteria for CSF leakage were:observed leak of CSF through the wound, rhinorrhea or otorrhea. Pseudomeningocele was determined when there was a large epidural CSF collection diagnosed in the postoperative period or by magnetic resonance imaging performed at least three months after posterior fossa surgery. Finally, CSF infection was defined on clinical ground and positive biochemical examination, but not necessarily positive cultures. RESULTS: The series included 84 operations for resection of posterior fossa tumors on 71 patients. There were CSF related complications in 31% (26/84)with the following detailed incidence: 9.5% (8/84) postoperative hydrocephalus; 14.3% (12/84) CSF leak, 7.1% (6/84) pseudomeningocele; 8.3% (7/84) CSF infection. The mortality rate is 5.9% (5/84). The tumor size was the only statistically significant factor associated with the occurrence of CSF related complications (mean 39.43 mm, SD 18.51 mm vs.29.80 mm, SD 14.12 mm, p=0.015). In the subgroup of patients, in which hydrocephalus was managed preoperatively, the election of an external ventricular drain vs.other strategies (subcutaneous reservoir, definite shunt or endoscopic third ventriculostomy) was associated with a higher occurrence of CSF related complications (p=0.006). The mortality rate was associated with age (mean 63.60 years, SD 5.86 years vs.49.18 years, SD 16.39 years; p=0.002). The occurrence of CSF related complications also influenced mortality (p=0.030), particularly postoperative hydrocephalus (p< 0.001). Inpatient hospital stay was longer in the subgroup of patients who developed CSF related complications (p=0.002). CONCLUSIONS: Tumor size was the only factor associated with the development of CSF related complications after surgery for posterior fossa tumors. In the subgroup of patients in which hydrocephalus was surgically treated preoperatively, the election of an external ventricular drain compared to other surgical modalities was associated with a higher rate of CSF related complications. The development of such complications, particularly hydrocephalus, was related with mortality.

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Introducción. Hidrocefalia, fístula de líquido cefalorraquídeo (LCR), pseudomeningocele e infección son complicaciones potenciales en la cirugía de los tumores de fosa posterior agrupadas bajo el término complicaciones licuorales. El objetivo de este estudio ha sido identificar variables relacionadas con la aparición de estas complicaciones en la cirugía de los procesos expansivos de fosa posterior.Material y métodos. La población objeto de estudio es una serie de 71 pacientes consecutivos intervenidos de un proceso expansivo de fosa posterior durante el período Enero 1997 - Diciembre 2001. Mediante revisión de historias clínicas se recogió la presencia de dichas complicaciones de acuerdo a los siguientes criterios: hidrocefalia postquirúrgica siempre que un mayor grado de dilatación ventricular respecto a las pruebas de neuroimagen preoperatorias y el cuadro clínico asociado a dicha dilatación condicionara una maniobra quirúrgica; fístula, cuando se detectara fuga de LCR a través de la herida quirúrgica, nariz u oído; pseudomeningocele, ante una colección epidural significativa de LCR detectada en el postoperatorio inmediato o en una resonancia magnética realizada más de tres meses después de la intervención; e infección de LCR, ante un cuadro clínico y un examen bioquímico de LCR compatibles con o sin cultivo positivo de LCR.Resultados. La serie incluye 84 procedimientos quirúrgicos de fosa posterior realizados a 71 pacientes. En el 31 por ciento (26/84) de los procedimientos se detectaron complicaciones licuorales con la siguiente incidencia pormenorizada: 9.5 por ciento (8/84) hidrocefalia postoperatoria; 14.3 por ciento (12/84) fístula de LCR; 7.1 por ciento (6/84) pseudomeningocele; 8.3 por ciento (7/84) infección de LCR. La mortalidad de la serie es del 5.9 por ciento (5/84). La única variable relacionada con la aparición de complicaciones licuorales fue el tamaño de la lesión (media 39.43 mm, DE 1851 mm vs. 29.80 mm, DE 14.12 mm, p=0.015). En el subgrupo de pacientes en que se efectuó una intervención quirúrgica para el control preoperatorio de la hidrocefalia, la elección de un drenaje ventricular externo vs. otras opciones (reservorio subcutáneo, shunt o ventriculostomía endoscópica) se asoció con una mayor tasa de complicaciones licuorales (p=0.006). La mortalidad se relacionó con la edad (media 63.60 años, DE 5.86 años vs. 49.18 años, DE 16.39 años, p=0.002) y con la presencia de complicaciones licuorales (p=0.030), particularmente con el desarrollo de hidrocefalia postoperatoria (p<0.001). La estancia hospitalaria postoperatoria fue más prolongada en el subgrupo de pacientes que desarrolló complicaciones licuorales (p=0.002).Conclusiones. El tamaño del tumor es la única variable relacionada con la aparición de complicaciones licuorales en la cirugía de los tumores de fosa posterior. En el subgrupo de pacientes en que se hace alguna maniobra quirúrgica para el control preoperatorio de la hidrocefalia, la elección de un drenaje ventricular externo comparado a otras opciones se asocia con una tasa mayor de complicaciones licuorales. La mortalidad quirúrgica está relacionada con el desarrollo de complicaciones licuorales, sobre todo con la hidrocefalia postoperatoria (AU)

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OBJECTIVE: The results obtained with therapy of intracranial aneurysms, in terms of morbidity and mortality, are very important when the patient has to choose between microsurgical techniques or endovascular management. The aim of this paper is to review the information regarding current microsurgical treatment of intracranial aneurysms, and presenting our experience over the last five years. MATERIAL AND METHODS: We studied 101 consecutive patients with 121 intracranial aneurysms admitted between 1996 and 2000 with the initial diagnosis of subarachnoid hemorrhage. We paid special attention to the day of admission from the onset of the symptomatic hemorrhage to the grade of Hunt&Hess scale and the possibility of early or delayed microsurgical treatment. The diagnosis was based on four vessels cerebral angiography and in a few cases with CT-angiography. All patients were treated by microsurgical technique and such treatment was completed by nimodipine, intensive care unit management and in some cases of postoperative suspected vasospasm, induced arterial hypertension was applied. Post surgical angiography was carried out in all patients to confirm the clipping of the cerebral aneurysm. The 12 months assessment was based on the Glasgow Outcome Scale (GOS). RESULTS: The 92.1% of the patients were admitted with a grade equal or below III in the Hunt&Hess scale. A 80% were operated within the 72 hours of admission and in the remaining cases, the surgical treatment was delayed due to a grade IV or V or to a medical contraindication. Four patients died (3.9%). At 12 months follow up, 88.9% presented a score I or II in the GOS. CONCLUSION: According to our results, there are a substantial improvements in the microsurgical treatment of cerebral aneurysms, specially in patients admitted early after the onset of the symptoms of their hemorrhage, who have a grade I to III in the Hunt&Hess scale and showed a good level of consciousness. We think that the improvement of our results are due to: l. the high percentage of patients admitted with grades I to III. 2. the high percentage of patients operated within the first 72 hours from the onset of their symptomatic hemorrhage. 3. surgery was always carried out by the same two experienced vascular neurosurgeons. 4. intraoperative measures taken to prevent the rupture of the aneurysm. 5. early administration of nimodipine, ICU management, doppler studies and in seldom cases, induced hypertension therapy to treat the vasospasm and postoperative hypotension.

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Objetivo: Los resultados, tanto de morbilidad como de mortalidad, en pacientes con aneurismas intracraneales, son de gran importancia a la hora de presentarle a un enfermo la posibilidad de elegir entre realizar un tratamiento, vía técnica microquirúrgica o endovascular. La idea de este artículo es, fundamentalmente, dar una información reciente sobre el estado actual del tratamiento microquirúrgico de los aneurismas intracraneales, presentando nuestra experiencia y resultados de los últimos cinco años. Material y métodos: Se han estudiado 101 pacientes con 121 aneurismas intracraneales que ingresaron de forma consecutiva entre los años de 1996 al 2000, bajo el diagnóstico de hemorragia subaracnoidea. Especial atención se prestó al día de su ingreso en relación con el comienzo de su hemorragia subaracnoidea, grado de Hunt&Hess y a la posibilidad de una cirugía precoz o demorada. El diagnóstico se realizó mediante examen panagiográfico y en algún caso aislado con Angio-TC. Todos fueron intervenidos mediante téc-nica microquirúrgica y dicho tratamiento fue completado mediante nimodipino, UCI y en algunos casos de sospecha de vaso espasmo postoperatorio, mediante hipervolemia. Su seguimiento fue evaluado mediante angiografía postoperatoria y la GOS. Resultados: 92.1 por ciento de los pacientes ingresaron con un grado igual o menor de III en la escala de Hunt&Hess. 80.8 por ciento fueron intervenidos en las primeras 72 horas y en el resto se demoró este tratamiento, bien por presentar el enfermo un grado IV ó V de Hunt&Hess o por causas médicas. Cuatro enfermos fallecieron (3.9 por ciento). El examen de la GOS a los doce meses de la cirugía mostró que el porcentaje de excelentes o buenos resultados alcanzó un 88.9 por ciento. Conclusión: De acuerdo con los resultados, se puede decir que existe un avance en la mejoría del tratamiento microquirúrgico de los aneurismas intracraneales en Neurocirugía 2003; 14: 5-15 general y sobre todo en aquellos pacientes que ingresan de forma inmediata a su sangrado y con buen nivel de conciencia grado I-III de Hunt&Hess).Por parte de nuestro estudio, la mejoría de los resultados pueden justificarse por: 1° el alto porcentaje de enfermos con HSA ingresados en grado I-III de Hunt&Hess e intervenidos precozmente. 2° la cirugía fue siempre realizada por los mismos dos cirujanos, con larga experiencia en patología vascular cerebral. 3° las medidas tomadas para disminuir la incidencia intra operatoria de rotura aneurismática. 4° el uso de nimodipino, la vigilancia en UCI, la utilidad del doppler y el tratamiento de hipervolemia en casos de sospecha de vaso espasmo o hipotensión postoperatoria (AU)

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Despite decades of investigation and discussion of the mechanisms involved in the pathophysiology of arachnoid cysts, fundamental issues concerning these entities remain poorly defined and controversial. Cine-mode magnetic resonance imaging (MRI) has shown two patterns of cerebrospinal fluid (CSF) flow within the cavity in patients harbouring arachnoid cysts. Some cysts present a harmonic flow with a patent flow entry zone. All these patients had intermittent, non-progressive and non-localizing symptoms requiring no surgery according to our criteria. The second pattern of CSF flow is more chaotic and is characterized by the presence of swirls throughout the entire cardiac cycle. This pattern is associated with a more disabling clinical picture. Some of these patients required surgical treatment. During surgery, an endoscope was used for inspection purposes revealing, above all, that arachnoid cysts always and variably communicate with the subarachnoid space. The CSF enters the cyst either through a patent flow entry zone or through minute perforations in areas more loosely packed of the arachnoid network that behave as a flexible mesh able to modify the area of flowing CSF. The slipstreams of CSF within arachnoid cysts may not be channelled properly leading to possible damage of the surrounding brain parenchyma.

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Two experiments were conducted on dogs to evaluate interval to initiation and duration of the first blood meal of Ctenocephalides canis (Curtis). Percentage of fed male and female fleas was calculated for fleas held on dogs for 5, 15, 30, 60 min, 6, and 24 hr. Duration of first blood meal was also measured for individual fleas confined on dogs. When fleas were free in the hair coat, 21.2% had begun blood feeding within 5 min. After 1 hr, 72.5% of fleas had fed. After 6 hr, 95.2% of males and 100% of females had taken a blood meal, and 24 hr after deposition all fleas had fed. There was no significant difference between the 2 sexes. The mean delay between deposition and biting for fleas that began feeding within 15 min was 2 min 52 sec +/- 3 min 2 sec for female fleas and 3 min 8 sec +/- 2 min 45 sec for males. The mean duration of female and male meals was 5 min 3 sec +/- 3 min 41 sec and 6 min 9 sec +/- 6 min 8 sec, respectively. There was no significant difference between the 2 sexes. The dog flea took its blood meal on dogs more slowly than the cat flea did on cats; this meal was significantly longer for Ctenocephalides felis felis (Bouche) than for C. canis.

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OBJECTIVES: The fibreoptic device is a type of intracranial pressure monitor which seems to offer certain advantages over conventional monitoring systems. This study was undertaken to analyse the accuracy, drift characteristics, and complications of the Camino fibreoptic device. METHODS: One hundred and eight Camino intracranial pressure (ICP) devices, in their three modalities, were implanted during 1997. The most frequent indication for monitoring was severe head injury due to road traffic accidents. RESULTS: Sixty eight probe tips were cultured; 13.2% of the cases had a positive culture without clinical signs of infection, and 2.9% had a positive culture with clinical signs of ventriculitis. The most common isolated pathogen was Staphylococcus epidermidis. All patients were under cephalosporin prophylaxis during monitoring. Haemorrhage rate in patients without coagulation disorders was 2.1% and 15.3% in patients with coagulation abnormalities. Drift characteristics were studied in 56 cases; there was no drifting from the values expected according to the manufacturer's specifications in 34 probes. There was no relation between direction of the drift and duration of placement, nor between drift and time. CONCLUSIONS: Although the complication and drift rates were similar to those reported elsewhere, there was no correlation between the direction of the drift and long term monitoring despite the fact that some published papers refer to overestimation of values with time with this type of device.

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