Fuat Arikan

Intra-abdominal pressure: the neglected variable in selecting the ventriculoperitoneal shunt for treating hydrocephalus.

OBJECTIVEIn the selection of a ventriculoperitoneal cerebrospinal fluid shunt, the intra-abdominal pressure (IAP) is traditionally neglected as a result of the idea that its value is close to 0 mmHg. Our aim was to explore the relationship between body mass index (BMI) and IAP with the goal of providing clinically relevant data that could help neurosurgeons to estimate IAP and select the appropriate shunt for patients with hydrocephalus and especially those with normal-pressure hydrocephalus syndrome. METHODSSixty patients requiring the placement of a ventriculoperitoneal shunt were included in the study. We determined weight, BMI, and IAP. IAP was measured through an intraperitoneal catheter during the shunt surgery. To determine whether a linear relationship existed between quantitative variables, linear regression analysis was used. RESULTSBMI was 28.1 ± 4.8 kg/m2. Eighteen patients (30%) had normal weight, 21 (35%) were moderately overweight, and 21 (35%) were obese. IAP was related to patient BMI. A significant positive linear correlation was identified between BMI and IAP (r = 0.52; P = 0.018) with a slope of 0.31 (P < 0.001) and an intercept of −5.5. CONCLUSIONIn our study, we determined that IAP had a strong positive linear relationship with BMI. This correlation was independent of sex. An IAP of 0 mmHg can, therefore, only be assumed for patients with a normal BMI who are recumbent. In obese or overweight patients, neurosurgeons should take IAP into account when selecting both the most adequate differential pressure valve to be implanted and in which distal cavity to place the distal catheter to avoid shunt underdrainage induced by high IAP.

Lactate and the Lactate-to-Pyruvate Molar Ratio Cannot Be Used as Independent Biomarkers for Monitoring Brain Energetic Metabolism: A Microdialysis Study in Patients with Traumatic Brain Injuries

Background For decades, lactate has been considered an excellent biomarker for oxygen limitation and therefore of organ ischemia. The aim of the present study was to evaluate the frequency of increased brain lactate levels and the LP ratio (LPR) in a cohort of patients with severe or moderate traumatic brain injury (TBI) subjected to brain microdialysis monitoring to analyze the agreement between these two biomarkers and to indicate brain energy metabolism dysfunction. Methods Forty-six patients with an admission Glasgow coma scale score of ≤13 after resuscitation admitted to a dedicated 10-bed Neurotraumatology Intensive Care Unit were included, and 5305 verified samples of good microdialysis data were analyzed. Results Lactate levels were above 2.5 mmol/L in 56.9% of the samples. The relationships between lactate and the LPR could not be adequately modeled by any linear or non-linear model. Neither Cohen’s kappa nor Gwet’s statistic showed an acceptable agreement between both biomarkers to classify the samples in regard to normal or abnormal metabolism. The dataset was divided into four patterns defined by the lactate concentrations and the LPR. A potential interpretation for these patterns is suggested and discussed. Pattern 4 (low pyruvate levels) was found in 10.7% of the samples and was characterized by a significantly low concentration of brain glucose compared with the other groups. Conclusions Our study shows that metabolic abnormalities are frequent in the macroscopically normal brain in patients with traumatic brain injuries and a very poor agreement between lactate and the LPR when classifying metabolism. The concentration of lactate in the dialysates must be interpreted while taking into consideration the LPR to distinguish between anaerobic metabolism and aerobic hyperglycolysis.

Aplicaciones de la telerradiologia al cribaje y manejo de los pacientes con un traumatismo craneoencefálico. Resultados de un estudio piloto de interconexión entre un hospital comarcal y un centro de referencia neuroquirurgico

Resumen La centralizacion de los servicios de Neurocirugia condiciona que los pacientes que sufren un traumatismo craneal, y que son atendidos de forma inicial por centros comarcales, deban ser remitidos al hospital neuroquirurgico para su valoracion. Esto supone el desplazamiento de un numero elevado de pacientes que, una vez valorados, regresan al centro emisor. La incorporacion de la telerradiologia puede limitar el traslado a aquellos casos que requieren una asistencia mas especializada. Objetivos : 1) presentar la experiencia inicial y los resultados de un estudio piloto de interconexion telerradiologica entre un hospital comarcal y un hospital de tercer nivel para la valoracion neuroquirurgica de pacientes con un traumatismo craneoencefalico (TCE), 2) describir la infraestructura y el soporte tecnologico necesario para este tipo de proyectos, 3) analizar las repercusiones del establecimiento de una conexion telerradiologica en los centros implicados (emisor y receptor), 4) evaluar la efectividad del sistema para evitar traslados innecesarios y 5) evaluar la efectividad en mejorar la rapidez y calidad en el traslado de los pacientes neurotraumaticos. Material y Metodos En enero de 1998, la Unidad de Neurotraumatologia del Hospital Universitario Vali d’Hebron establece una conexion telerradiologica con el Hospital General de Vic para la valoracion neuroquirurgica de pacientes con un TCE. La informacion clinica de cada paciente se recibe por fax convencional. Las imagenes de la TC cerebral, que han sido digitalizadas, comprimidas y preparadas para su transmision con el programa StatView™, se trasmiten via modem a nuestro centro. La visualizacion de estas imagenes se realiza en la pantalla de un PC convencional dotado del software MultiView™. Despues de valorada la exploracion neurorradiologica, el neurocirujano de guardia emite el informe pertinente al hospital emisor con las indicaciones a seguir respecto al traslado del paciente o su tratamiento (ingreso, observacion etc.). Resultados Analizamos los resultados de nuestra experiencia despues de 5 anos del inicio de este tipo de conexion telerradiologica. Conclusiones La utilizacion de la telerradiologia en el manejo diario de los pacientes con un TCE aporta un claro beneficio asistencial y supone una mayor racionalizacion de los recursos, redundando en un importante ahorro economico para el sistema sanitario. La efectividad del sistema en reducir los tiempos accidente-tratamiento en los casos graves, depende mas de la infraestructura sanitaria de cada area geografica que de sistemas sofisticados de telemedicina. La imple-mentacion de estos metodos debe ir acompanada de otras medidas de ambito politico/sanitario dirigidas a conseguir un traslado mas rapido de los pacientes seleccionados.

Rapid Resolution of Brain Ischemic Hypoxia After Cerebral Revascularization in Moyamoya Disease

BACKGROUND In moyamoya disease (MMD), cerebral revascularization is recommended in patients with recurrent or progressive ischemic events and associated reduced cerebral perfusion reserve. Low-flow bypass with or without indirect revascularization is generally the standard surgical treatment. Intraoperative monitoring of cerebral partial pressure of oxygen (PtiO2) with polarographic Clark-type probes in cerebral artery bypass surgery for MMD-induced chronic cerebral ischemia has not yet been described. OBJECTIVE To describe basal brain tissue oxygenation in MMD patients before revascularization as well as the immediate changes produced by the surgical procedure using intraoperative PtiO2 monitoring. METHODS Between October 2011 and January 2013, all patients with a diagnosis of MMD were intraoperatively monitored. Cerebral oxygenation status was analyzed based on the Ptio2/PaO2 ratio. Reference thresholds of PtiO2/PaO2 had been previously defined as below 0.1 for the lower reference threshold (hypoxia) and above 0.35 for the upper reference threshold (hyperoxia). RESULTS Before STA-MCA bypass, all patients presented a situation of severe tissue hypoxia confirmed by a PtiO2/PaO2 ratio <0.1. After bypass, all patients showed a rapid and sustained increase in PtiO2, which reached normal values (PtiO2/PaO2 ratio between 0.1 and 0.35). One patient showed an initial PtiO2 improvement followed by a decrease due to bypass occlusion. After repeat anastomosis, the patients PtiO2 increased again and stabilized. CONCLUSION Direct anastomosis quickly improves cerebral oxygenation, immediately reducing the risk of ischemic stroke in both pediatric and adult patients. Intraoperative PtiO2 monitoring is a very reliable tool to verify the effectiveness of this revascularization procedure.

Intraoperative monitoring of brain tissue oxygenation during arteriovenous malformation resection.

Background: In normal perfusion pressure breakthrough (NPPB) it is assumed that following arteriovenous malformation (AVM) resection, vasoparalysis persists in the margins of the lesion and that a sudden increase in cerebral blood flow (CBF) after AVM exclusion leads to brain swelling and postsurgical complications. However, the pathophysiology NPPB remains controversial. The aim of our study was to investigate the oxygenation status in tissue surrounding AVMs and in the distant brain using intraoperative monitoring of cerebral partial pressure of oxygen (PtiO2) to achieve a better understanding of NPPB pathophysiology. Methods: Patients with supratentorial AVMs were monitored intraoperatively using 2 polarographic Clark-type electrodes. To establish reference values, we also studied PtiO2 in a group of patients who underwent surgery to treat incidental aneurysms. Results: Twenty-two patients with supratentorial AVMs and 16 patients with incidentally found aneurysms were included. Hypoxic pattern was defined as PtiO2⩽15 mm Hg and/or PtiO2/PaO2 ratio ⩽0.10. Tissue hypoxia was detected in 63.6% of the catheters placed in the perinidal area and in 43.8% of catheters placed in a distant area. AVM excision significantly improved oxygenation both around the AVM and in the distant area. Conclusions: The PtiO2/PaO2 ratio is a better indicator than absolute PtiO2 in detecting tissue hypoxia in mechanically ventilated patients. Intraoperative monitoring showed tissue hypoxia in the margins of AVMs and in the distant ipsilateral brain as the most common finding. Surgical removal of AVMs induces a significant improvement in the oxygenation status in both areas.

Craniectomía descompresiva primaria en la hemorragia subaracnoidea aneurismática. Resultados de un estudio piloto en 11 casos

Resumen Introduccion A pesar de los avances cientificos y tecnicos de los ultimos anos, la hemorragia subaracnoidea aneurismatica (HSAa) sigue presentando una alta morbilidad y mortalidad. Este hecho, junto con los impresionantes resultados de la craneotomia descompresiva primaria (CDP) en el infarto maligno de la arteria cerebral media sugiere la posibilidad que la CDP sea una alternativa terapeutica a considerar en algunos pacientes con una HSAa. Presentamos nuestra experiencia de un estudio piloto en el que se utilizo la CDP en pacientes con HSAa en mal grado neurologico y hematoma intracerebral asociado. Pacientes y metodos Entre el 1 de marzo de 2002 y el 31 de abril de 2008, se trataron 342 pacientes con HSAa en nuestro hospital. De estos, 64 tenian una puntuacion de 4 o 5 de la escala de la WFNS (World Federation of Neurosurgical Societies). En el presente estudio prospectivo se analizan 11 pacientes en los que se realizo una CDP durante la misma cirugia de clipaje o/y evacuacion del hematoma asociado. Resultados En tres pacientes la CDP se realizo despues del tratamiento endovascular del aneurisma debido a la necesidad de evacuar el hematoma asociado. En los ocho pacientes restantes, la CDP se realizo durante el clipaje y la evacuacion del hematoma asociado. La evaluacion de los resultados de estos once pacientes se llevo a cabo al ano de la cirugia mediante la escala de resultados de Glasgow. La CDP fue eficaz en el control de presion intracraneal en los pacientes que sobrevivieron. Seis pacientes sobrevivieron, cuatro de ellos con un buen resultado neurologico. Sin embargo, dos de estos seis pacientes tuvieron un resultado desfavorable. De los cinco pacientes que no sobrevivieron, un paciente murio a causa de un hematoma subgalealepidural diferido como complicacion de la CDP, y los restantes cuatro pacientes fallecieron a causa de una hipertension intracraneal refractaria. Conclusiones La CDP puede ser una alternativa terapeutica en un grupo seleccionado de pacientes con HSAa con mal grado neurologico. Sin embargo, en la actualidad hay una falta de evidencia para apoyar unas recomendaciones claras para su uso.

La incorporación de Neurocirugía al Journal of Citation Reports: análisis bibliométrico de la producción científica neuroquirúrgica española

Resumen Introduccion y Objetivos La edicion de 1998 del Journal of Citation Reports incluye por primera vez a la revista Neurocirugia entre las publicaciones analizadas. Esto supone la incorporacion de nuestra revista al grupo mas selecto de publicaciones cientificas internacionales y le otorga el deseado factor de impacto. En este trabajo hemos tratado de revisar los conceptos bibliometricos basicos que rigen la influencia de las publicaciones y grupos de investigacion en ciencias biomedicas, conocer el estado actual de la produccion cientifica en neurocirugia y la situacion de Espana en el contexto mundial y europeo, analizando su distribucion nacional y evolucion en los ultimos anos, y exponer la situacion actual de la revista Neurocirugia planteando algunas reflexiones para mejorar sus indicadores en el futuro. Materialy metodos Hemos realizado una revision de la literatura neuroquirurgica durante 1998 y un seguimiento de la produccion nacional en el periodo 1987–99, distribuyendo los articulos segun la procedencia geografica de sus autores, revistas, areas y tipos de investigacion. Los datos fueron obtenidos principalmente desde MEDLINE. Las variables bibliometricas principales analizadas fueron el numero total de articulos y el factor de impacto. Los datos absolutos se han ponderado con variables demograficas y economicas para conocer el potencial relativo de cada pais. Resultados Se localizaron 3.021 articulos publicados en 314 revistas durante 1998. Los principales paises productores fueron los Estados Unidos, Japon y Alemania, tanto por numero total de articulos como por factor de impacto acumulado. Espana ocupa la novena plaza mundial por numero de articulos publicados y la decimotercera por factor de impacto. El producto interior bruto ha sido la variable correctora que ha demostrado una correlacion mas fuerte con la produccion cientifica generada por cada pais y, aplicandola, nuestro pais desciende considerablemente. La produccion espanola muestra, no obstante, una tendencia favorable en los ultimos anos, no tanto por el numero total de articulos publicados sino por la teorica mayor calidad de los mismos. Conclusiones Pese a los logros conseguidos en los ultimos anos, la neurocirugia espanola ocupa una posicion inferior a la que corresponde al potencial economico de nuestro pais. El reto de los proximos anos sera trabajar para elevar estos indicadores.

Variabilidad en el manejo de la hemorragia subaracnoidea aneurismática en España: análisis de la base de datos multicéntrica del Grupo de Trabajo de Patología Vascular de la Sociedad Española de Neurocirugía

INTRODUCTION In aneurysmal subarachnoid haemorrhage, endovascular or surgical exclusion of the aneurysm responsible for the bleeding is mandatory to prevent re-bleeding. In Spain there is no data regarding the frequency of usage of the two techniques, the moment treatment is performed, the existence of variability among the different centres treating these patients or the factors that determine the election of the therapeutic modality. OBJECTIVES 1) To describe the variability in the use of endovascular treatment or surgery in the treatment of these patients among the participating centres. 2) To establish which factors are related to the election of treatment and outcome. MATERIALS AND METHODS Of all the patients included in the database, we selected 2,150 cases suffering confirmed aneurysmal subarachnoid haemorrhage from 10 centres that included patients regularly during the period between 2004 and 2012 with a data completeness index over 95%. A descriptive analysis on mode of aneurysm treatment was performed. A multivariate analysis of the factors related to treatment modality of the aneurysm and outcome was performed using logistic regression. RESULTS The ratio endovascular/surgical treatment was 1.32. There was high variability among centres regarding the frequency of endovascular treatment (32-80%). No treatment was given to 17% of the aneurysms, with this percentage being higher in the centres with lower rates of endovascular treatment. Lower volume centres treated aneurysms later. Age and poor clinical grade were factors related to the election of endovascular treatment, while middle cerebral artery location and unfavourable morphological criteria were factors of surgical treatment. The choice of treatment, guideline adherence and centre patient volume were not related to outcome. CONCLUSIONS There is high variability in the election of treatment modality among centres in Spain. Endovascular treatment allows more patients to have their aneurysm treated. Guideline adherence is moderate.

Variabilidad en las indicaciones quirúrgicas de las lesiones intradurales postraumáticas

Resumen Introduccion El tratamiento de las lesiones focales intradurales continua siendo motivo de controversia. Esto es especialmente importante en la decision de evacuar contusiones cerebrales. Presentamos los resultados de un estudio prospectivo y observacional, cuyo objetivo ha sido analizar la variabilidad en las indicaciones quirurgicas de lesiones focales intradurales postraumaticas en un servicio de neurocirugia perteneciente a un hospital universitario, dotado de una unidad especializada en neurotraumatologia. Material y metodos Entre el 1 de mayo y el 31 de diciembre de 2001, se incluyeron 32 pacientes con un traumatismo craneoencefalico (TCE) cerrado, con lesiones focales intradurales. Estos pacientes constituyen la aportacion que nuestro centro realizo en el estudio multicentrico y observacional sobre el manejo de lesiones intradurales dirigido por el European Brain Injury Consortium (EBIC). Resultados Las lesiones intradurales de volumen > 25 cc. se evacuaron de forma inmediata al diagnostico. Nueve de los 13 pacientes con lesiones Conclusiones A pesar que el reducido numero de casos incluidos no nos permiten generalizar las conclusiones, en nuestro centro no se evidencia una variabilidad significativa en las indicaciones quirurgicas de lesiones > 25 cc. Sin embargo, existen discrepancias en las indicaciones quirurgicas de las lesiones con volumen

Prognosis of patients in coma after acute subdural hematoma due to ruptured intracranial aneurysm.

Acute subdural hematomas (aSDH) secondary to intracranial aneurysm rupture are rare. Most patients present with coma and their functional prognosis has been classically considered to be very poor. Previous studies mixed good-grade and poor-grade patients and reported variable outcomes. We reviewed our experience by focusing on patients in coma only and hypothesized that aSDH might worsen initial mortality but not long-term functional outcome. Between 2005 and 2013, 440 subarachnoid hemorrhage (SAH) patients were admitted to our center. Nineteen (4.3%) were found to have an associated aSDH and 13 (2.9%) of these presented with coma. Their prospectively collected clinical and outcome data were reviewed and compared with that of 104 SAH patients without aSDH who presented with coma during the same period. Median aSDH thickness was 10mm. Four patients presented with an associated aneurysmal cortical laceration and only one had good recovery. Overall, we observed good long-term outcomes in both SAH patients in coma with aSDH and those without aSDH (38.5% versus 26.4%). Associated aSDH does not appear to indicate a poorer long-term functional prognosis in SAH patients presenting with coma. Anisocoria and brain herniation are observed in patients with aSDH thicknesses that are smaller than those observed in trauma patients. Despite a high initial mortality, early surgery to remove the aSDH results in a good outcome in over 60% of survivors. Aneurysmal cortical laceration appears to be an independent entity which shows a poorer prognosis than other types of aneurysmal aSDH.