Anatomía radiológica de la base de cráneo y los nervios craneales parte 2: Nervios craneales / Skull base and cranial nerves radiologic anatomy part 2: Cranial nerves

Resumen: La anatomía de la base del cráneo es compleja. Numerosas estructuras neurovasculares vitales pasan a través de múltiples canales y agujeros ubicados en la base del cráneo. Con el avance de la tomografía computarizada (TC) y la resonancia magnética (RM), es posible la localización cada vez más precisa de lesiones y la evaluación de su relación con las estructuras neurovasculares adyacentes. El trayecto de los nervios craneales sigue un recorrido conocido y se transmiten a la cara y cuello por los forámenes de base de cráneo. La tomografía computada y la resonancia magnética son complementarias entre sí y, a menudo, se usan juntas para demostrar la extensión total de la enfermedad. La segunda parte de esta revisión se centra en el estudio radiológico de los nervios craneales.

Abstract: The skull base anatomy is complex. Many vital neurovascular structures course through the skull base canals and foramina. With the advancement of CT and MRI, the localization of lesions has become more precise as their relationship with adjacent neurovascular structures. There is a known course of the cranial nerves as well as their skull base exiting foramina to the head and neck. CT and MRI are complimentary modalities and are often used together to map the full extent of disease. The second article in this review focus on the radiologic study of the cranial nerves.

Proteína C reactiva de alta sensibilidad como predictor de fibrilación auricular postoperatoria / High-sensitivity C-reactive protein predicts postoperative atrial fibrillation

Introducción: La fibrilación auricular postoperatoria (FAPO) es una complicación frecuente en la cardiocirugía con circulación extracorpórea (CEC). El evento de isquemia-reperfusión secundario a la CEC produce inflamación como mediador de daño miocárdico causando FAPO. Objetivo: determinar el poder predictivo del marcador de inflamación proteína C reactiva de alta sensibilidad (hsCRP) en la FAPO. Hipótesis: la hsCRP predice la ocurrencia de FAPO. Material y Método: estudio observacional, analítico, incluyó 123 pacientes sometidos a cardiocirugía con CEC en el Hospital Clínico de la Universidad de Chile entre 2007 y 2010. El muestreo fue aleatorio simple de pacientes concurrentes a cirugía cardíaca. Se realizó monitoreo electrocardiográfico continuo y medición de hsCRP plasmática antes de la cirugía, 8 horas postoperatorias y al alta. Se realizó un análisis de regresión multivariada, considerando los factores de riesgo conocidos de FAPO, así como la hsCRP. Para variable cuantitativa continua, se realizó ANOVA-Bonferroni. Para análisis de Kaplan-Meier de cuartiles de hsCRP, se realizó test de tendencia log-rank. Se realizó una receiver operator curve (ROC) para determinar el poder predictivo de la hsCRP. Significancia: p<0,05. Resultados: Se describe el perfil clínico-epidemiológico de los pacientes. La hsCRP fue máxima a las 8 horas postoperatorias (ANOVA-Bonferroni p<0,01). El análisis de regresión multivariada relacionó significativamente hsCRP y ocurrencia de FAPO (p<0,01). A mayor cuartil de hsCRP se asoció mayor ocurrencia de FAPO (p<0,01). El área bajo la curva ROC fue 0,73. Discusión: La hsCRP postoperatoria constituye una valiosa herramienta predictora de ocurrencia de FAPO en el contexto de cirugía cardíaca con CEC.

Introduction: Postoperative atrial fibrillation (POAF) is a common complication of cardiac surgery with extracorporeal circulation. Is associated with increased morbidity and health costs. The ischemia-reperfusion event secondary to extracorporeal circulation leads to inflammation, causing myocardial damage. Objective: The aim of this study is to determine the predictive power of high sensitivity C-reactive protein (hsCRP) in POAF.Hypothesis: hsCPR predicts POAF occurrence. Material and Method: An observational, analytical study, included 123 patients undergoing cardiac surgery with extracorporeal circulation at Universidad de Chile’s Hospital, between 2007 and 2010. Continuous electrocardiographic monitoring was performed and plasma hsCPR measurement before surgery, 8 hours postoperatively and at discharge. We performed a multivariate regressionanalysis considering the known risk factors for POAF and the hsCRP. For continuous quantitative variable ANOVA-Bonferroni was used. Kaplan-Meier analysis of quartiles of hsPCR was usedand Mantel-Cox log-rank test for trend test. Receiver operator curve (ROC) was performed to determine the predictive power of the hsPCR. Significance: p<0.05. Results: We describe the clinical and epidemiological characteristics of patients undergoingcardiac surgery. The hsCPR was highest at 8 postoperative hours (ANOVA-Bonferroni p<0.01). The multivariate regression analysis significantly correlated with the occurrence of hsPCRand POAF (p<0.01). The higher quartile of hsCPR was associated with increased occurrence of POAF (p<0.01). The area under the ROC curve was 0.73. Discussion: The postoperative hsPCR isa valuable predictor of the occurrence of POAF in the context of cardiac surgery with extracorporeal circulation.

Rabdomiolisis asociada a torniquete en cirugía de rodilla: importancia del estrés oxidativo y el rol del alopurinol en su prevención / Rhabdomyolysis associated with tourniquet in knee surgery: importance of oxidative stress and the role of allopurinol in the prevention

Orthopedic knee surgery using a tourniquet has allowed surgeons to operate with a bloodless field. Nevertheless, tourniquet application produces an ischemia-reperfusion cycle in the skeletal muscle. As a consequence of the reoxygenation of the muscle, an enhancement on the production of reactive oxygen species leads to cell dysfunction, apoptosis and necrosis. A mild rhabdomyolisis is ascertained from the average 7-fold increase in plasma creatine phosphokinase and myoglobin in these patients, with release of intracellular content such as uric acid and phosphate. Altogether, these factors ascertain a distant response, determined by systemic inflammation and renal involvement by means of glomerular and tubular damage. In contrast, it is likely that acute kidney injury remains under diagnosed due to the recent change in acute kidney failure diagnostic paradigm. As a plausible evidence-based intervention, a diminution on the production of reactive oxygen species seems the pathophysiological treatment. Indeed, allopurinol supplementation constitutes a reasonable, innocuous and cheap alternative for these patients, because of inhibition of xanthine oxidase, the latter being the main source of reactive oxygen species in the setting of ischemia-reperfusion. This review focuses on the pathophysiology of rhabdomyolisis and acute kidney injury in the context of tourniquet knee surgery and therapeutics on allopurinol.