Prevalence of anatomical variants of the Willis polygon in cadavers undergoing medico-legal necropsy / Prevalencia de variantes anatómicas del Polígono de Willis en cadáveres sometidos a necropsia medicolegal

The primary function of the circle of Willis is to provide collateral blood flow between the anterior and posterior arterial systems of the brain. Its configuration can vary considering its vascular structures, this being considered an anatomical variant. Our study aims to determine the prevalence of these, discriminated by sex in corpses subjected to medicolegal autopsy at the National Institute of Legal Medicine and Forensic Sciences in 2019, in Cali-Colombia. Retrospective observational descriptive study, of photographic records, inspection records and expert reports, where variables of age, sex, anatomical variants, compromised vascular structures are differentiated. Univariate and bivariate analyzes were performed. The population consisted of 194 cases, with a median age of 33 years (interquartile range between 23-45). 24.4% corresponded to the male sex. A prevalence of 25.3% of cases with non-classic polygon was observed. The most frequent anatomical variant was hypoplasia 14.9%. The vascular structure that presented the most anatomical variants was the posterior communicating artery with 17%.

La función principal del polígono de Willis es proporcionar flujo sanguíneo colateral entre los sistemas arteriales anterior y posterior del cerebro. Su configuración puede variar teniendo en cuenta sus estructuras vasculares, considerándose esto una variante anatómica. En este estudio analizamos la prevalencia de las variaciones, discriminada por sexo en cadáveres sometidos a necropsia medicolegal en el Instituto Nacional de Medicina Legal y Ciencias Forenses en el año 2019, en Cali-Colombia. Estudio descriptivo observacional retrospectivo, de registros fotográficos, actas de inspección e informes periciales, donde se diferencia variables de edad, sexo, variantes anatómicas, estructuras vasculares comprometidas. Se realizaron análisis uni y bivariados. La población estuvo conformada por 194 casos, con una mediana de edad de 33 años (rango intercuartil entre 23-45). El 24.4% correspondieron al sexo masculino. Un 25,3% de casosse encontró un polígono no clásico. La variante anatómica más frecuente fue la hipoplasia 14.9%. La estructura vascular que más variantes anatómicas presentó fue la arteria comunicante posterior con un 17%.

Vasoespasmo cerebral y déficit isquémico tardío en la hemorragia subaracnoídea aneurismática: guías para su manejo clínico / Cerebral vasospasm and delayed ischemic deficit in the aneurysmal subarachnoid hemorrhage: guidelines to its clinical management

La presente revisión del tema Vasoespasmo y Déficit Isquémico Cerebral tardío (DIT) en la Hemorragia subaracnoidea aneurismática tiene como objetivo actualizar su manejo, basado en las hipótesis mas aceptadas que se han logrado para explicar su patogénesis. Se efectúa una introducción con conceptos generales, se revisan las bases patogénicas del Vasoespasmo y se plantea su manejo, tomando en cuenta su diagnóstico, monitorización, profilaxis y manejo avanzado de acuerdo a las últimas Guías de Manejo Clínico y según medicina basada en las evidencias.

The objective of the present review on cerebral vasospasm and cerebral delayed isquemic deficit due to subarachnoid haemorrhage secondary to ruptured cerebral aneurysm, is to update their management, based on the most accepted pathophysiological hypotesis explaining their pathogenetic mechanisms. An introduction is performed presenting general concepts, review of the most recent research works explaining their pathogenesis, and the management is stated touching diagnosis, monitoring, prophylaxis, and advanced management according with the last clinical guidelines for his management using medicine based on evidences.

Carotid siphon geometry and variants of the circle of Willis in the origin of carotid aneurysms / Geometria do sifão carotídeo e variantes do polígono de Willis na origem de aneurismas da carótida

This study evaluated anatomical variants in the carotid siphon and of the circle of Willis in patients with aneurysms. We performed a retrospective analysis of cerebral angiographies. The Control Group was composed of patients without aneurysms. Posterior communicating artery (PcomA) aneurysms were more common in women (p<0.05), and the anterior communicating artery (AcomA) aneurysms in men (p<0.1). The incidence of fetal-type PcomA was higher in cases with co-occurring PcomA aneurysm (24 versus 8%, p<0.05). Patients with AcomA aneurysm had higher incidence of A1 hypoplasia (p<0.0001, OR=32.13, 95%CI 12.95-79.71) and lower frequency of fetal-type PcomA compared to their control counterparts (p=0.0125). The angle of carotid siphon was narrower in patients with PcomA aneurysm (27.3±19.1 versus 34.8±22.6, p=0.028). In conclusion, a narrower carotid siphon or the presence of fetal-type PcomA or A1 hypoplasia may cause hemodynamic stress, thereby promoting the formation of aneurysms in susceptible individuals.

O presente estudo avaliou as variantes anatômicas do sifão carotídeo e da parte posterior do polígono de Willis em pacientes com aneurismas. Foi realizada uma análise retrospectiva de angiografias cerebrais. O Grupo Controle foi composto por pacientes sem aneurismas. Aneurismas da artéria comunicante posterior (ACP) foram mais frequentes em mulheres (p<0,05), e aqueles da anterior (ACA) em homens (p<0,1). A incidência do tipo fetal da ACP foi maior nos casos com co-ocorrência de aneurisma da ACP (24 versus 8%, p<0,05). Pacientes com aneurisma da ACA tiveram maior incidência de hipoplasia A1 (p<0,0001, OR=32,13, IC95% 12,95-79,71) e menor frequência do da ACP fetal comparados com os controles (p=0,0125). O ângulo do sifão carotídeo era mais estreito em pacientes com aneurismas da ACP (27,3±19,1 versus 34,8±22,6, p=0,028). Em conclusão, um sifão carotídeo estreito e a presença de ACP fetal ou hipoplasia A1 podem causar estresse hemodinâmico, promovendo a formação de aneurismas em indivíduos suscetíveis.

Tratamiento quirúrgico de los aneurismas intracraneales gigantes de la circulación anterior del circulo de Willis / Surgical treatment of giant intracranial aneurysms of the anterior circulation of the circle of Willis

Introducción: Los aneurismas intracraneales gigantes, son lesiones con características muy particulares, que implican la utilización de métodos quirúrgicos específicos para su exclusión de la circulación, dependientes de su tamaño, localización, morfología, relaciones con otras estructuras neurales y vasculares, así como características propias del saco. Método: Se realiza un estudio descriptivo, de todos los pacientes portadores de aneurismas intracraneales gigantes, que fueron intervenidos quirúrgicamente en el servicio de neurocirugía del Hospital “Roberto Rodriguez”, de la ciudad de Morón, en la provincia de Ciego de Ávila, Cuba, en el período comprendido entre enero de 1996 y diciembre del 2008. La evaluación al ingreso fue con la escala de Hunt y Hess, el diagnóstico se obtuvo con imágenes de angiotomografía computarizada multicortes, angioresonancia magnética nuclear o angiografía cerebral. El corredor quirúrgico fue el frontopterional de Yasargil y se emplearon medidas adyuvantes para lograr el presillamiento. Resultados: La muestra estuvo representada por 13 pacientes. Predominaron los aneurismas de la comunicante posterior (61,53 por ciento), ocho (61,54 por ciento), debutaron con una hemorragia subaracnoidea y cinco (38,46 por ciento), con compresión de estructuras adyacentes. De los tres operados en fase aguda, dos fallecieron (ERG I) (66,67 por ciento) y uno (33,33 por ciento) quedó con secuelas severas (ERG III). Los operados en fase tardía, dos (20 por ciento) quedaron con secuelas severas (ERG III), tres (30 por ciento) mostraron secuelas moderadas (ERG IV) y cinco (50 por ciento) quedaron con secuelas ligeras o sin ellas (ERG V). La mortalidad global fue de 15,38 por ciento. Conclusiones: La microcirugía constituye un método eficaz en centros que no cuentan con tratamiento endovascular.

Introduction: The surgical treatment of giant intracraneal aneurysms aims to exclude them from the circulation and to reduce its mass effect while preserving normal vasculature. Method: We have carried out a descriptive study in thirteen patients with a giant aneurysm located in the anterior circulation of Willis circle operated on in neurological surgery department of Moron General Hospital, Ciego de Avila, Cuba between January of 1996 to December of 2008. The neurological status in emergency department was evaluated by Hunt and Hess scale, the results were evaluated by Glasgow outcome scale. The diagnosis was obtained by CT scan, MRI and conventional angiography. Results: From thirteen aneurysms, 9 were excluded of circulation (69,23 percent), 7 were clipped, 2 were trapped and 4 reinforced. Three patients were operated on in acute phase with poor grade aneurysmal subarachnoid hemorrhage, two of them died (66,67 percent) (GOS I), and one (33,33 percent) had a severe disability (GOS III). Delayed surgery was carried out in 10 patients, two of them (20 percent) showed severe disability (GOS III), 3 (30 percent) had moderate disability and 5 (50 percent) had favorable outcome (GOS 5). The global mortality in the group was 15,38 percent. Conclusion: Microsurgery is the more important treatment in countries without possibilities of endovascular treatment for giant intracranial aneurysms.

Moyamoya disease and Down syndrome.

Moyamoya disease is an obstruction of the internal carotids and of the afferent and efferent channels of Willis polygon, which causes a collateral circulation, responsible for the typical angiographic image of a "puff of smoke" (Moyamoya, in Japanese). Its etiology is unknown, and it might be congenital or acquired. The clinical features are cerebral ischemia, recurrent transient ischaemic attacks, sensorimotor paralysis, convulsions and migraine-like headaches. We report a 2 years and 9 months old boy with Down syndrome and Moyamoya disease who presented with focal convulsions.

An autopsy study of atherosclerosis in aorta, common carotid arteries and circle of Willis.

The incidence, extent and degree of atherosclerosis was studied in descending aorta, common carotid arteries and circle of Willis obtained from 50 cadavers above the age of 30 years. Specimens were stained grossly with Sudan IV and the total atherosclerotic area was measured and atherosclerotic index was calculated. The co-efficient of correlation between extent of atherosclerosis with age and nutritional status was calculated. The incidence of atherosclerosis was 100.0% in the aorta and common carotid arteries in all the specimens. In case of circle of Willis, it was 76.5% in the fourth decade and 87.5% in the fifth decade, rising to 100.0% thereafter. The atherosclerotic index increased with age at all the three locations. However, at any given age, the atherosclerotic index in circle of Willis was much less as compared to the aorta or common carotid arteries. The most prominent lesion in all the three groups of vessels in the fourth and fifth decades was the presence of a fatty streak. There was a sudden spurt in the extent of fibrous plaques in the aorta, carotid arteries and circle of Willis in the sixth decade. Complicated lesions also appeared in this decade, and became more marked after sixty years of age. The correlation between the extent and degree of atherosclerosis with age was found to be highly significant statistically (p < 0.001). A significant correlation (p < 0.001) was also found between the nutritional status and extent and degree of atherosclerosis. No conclusion could be derived regarding differences in the extent and degree of the disease in the two sexes.