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%.

Fetal-type variant of the posterior cerebral artery and concurrent bilateral cerebral infarctions in a Korean male cadaver / Variante de tipo fetal de la arteria cerebral posterior e infartos cerebrales bilaterales concurrentes en un cadáver masculino coreano

SUMMARY: Fetal-type variant of the posterior cerebral artery is a relatively common variant of the cerebral arterial circle (circle of Willis), but concurrent cerebral pathologies have not been well reported. We describe a case of fetal-type variant of the posterior cerebral artery and concurrent bilateral cerebral infarctions in the territories of the middle cerebral artery in a 78-year-old Korean male cadaver. Fetal-type variant of the posterior cerebral artery was found the right cerebral arterial circle, arose from the internal carotid artery with larger diameter than the pre-communicating segment from the basilar artery. Histopathological examination revealed that left supramarginal gyrus and right infraparietal lobule showed characteristic cerebral infarctions with chronological changes, respectively. Knowledge on the variation in the posterior cerebral artery combined with clinical features including cerebral infarction plays a pivotal role to anatomists and clinicians.

RESUMEN: La variante de tipo fetal de la arteria cerebral posterior es una variante relativamente común del círculo arterial cerebral (polígono de Willis) de arterial cerebral, pero las patologías cerebrales concurrentes no han sido bien informadas. Describimos un caso de variante de tipo fetal de la arteria cerebral posterior e infartos cerebrales bilaterales concurrentes en los territorios de la arteria cerebral media en un cadáver masculino coreano de 78 años. La variante de tipo fetal de la arteria cerebral posterior se encontró en la parte de derecha del círculo arterial cerebral, surgido de la arteria carótida interna con mayor diámetro que el segmento precomunicante de la arteria basilar. El examen histopatológico reveló que el giro supramarginal izquierdo y el lóbulo infraparietal derecho mostraban infartos cerebrales característicos con cambios cronológicos, respectivamente. El conocimiento sobre la variación en la arteria cerebral posterior combinado con las características clínicas, incluido el infarto cerebral es fundamental para los anatomistas y los médicos.

The association of the circle of Willis anomaly and risk of stroke in patients with carotid artery disease / A associação de anomalia de Círculo de Willis e o risco de AVC em pacientes com doença carotídea

ABSTRACT The circle of Willis is an important collateral system that maintains perfusion to the stenotic area from the contralateral carotid and basilar artery to the region of reduced brain perfusion. The aim of the present study was to compare the circle of Willis anomaly in patients with unilateral symptomatic and asymptomatic carotid artery disease. Results In this retrospective study, we analyzed 175 patients who presented at our outpatient stroke clinic between January, 2013 and June, 2015 with either unilateral symptomatic or asymptomatic carotid artery disease, and who had had CT angiography imaging performed. Demographic properties, carotid artery stenosis and the anomaly of the circle of Willis was recorded. Conclusion There was no statistically significant difference in patients with symptomatic and asymptomatic carotid artery disease in terms of the anomaly of the circle of Willis.

RESUMO O Círculo de Willis é um importante sistema colateral que mantém a perfusão à área estenótica da carótida contralateral e da artéria basilar para a região de perfusão cerebral reduzida. O objetivo do presente estudo foi comparar a anomalia do Círculo de Willis em pacientes com doença carotídea assintomática e sintomática unilateral. Resultados Neste estudo retrospectivo, foram analisados 175 pacientes que foram à nossa clínica ambulatorial de AVC, entre janeiro de 2013 e junho de 2015, com doença carotídea assintomática ou sintomática unilateral, e que fizeram angiografia por tomografia computadorizada. Propriedades demográficas, estenose da artéria carótida e anomalia do Círculo de Willis foram registradas. Conclusão Não houve diferença estatisticamente significativa em pacientes com doença carotídea sintomática e assintomática em termos de anomalia do Círculo de Willis.

Variations in the brain circulation: the circle of Willis

Introduction: Despite being quite common, there is little information concerning the Brazilian population on anatomic variations and anomalies in the brain circulation. This study intends to describe the most common variations found during the autopsies for the AMA Study. Material and methods: Fifty cadavers had their circle of Willis dissected and analyzed. Results: 54% presented at least one variation, and they were more common in the posterior circulation (88.5%) and on the right side of the brain (59.7%); non-classical morphology was more common bilaterally and in the posterior circulation of the circle of Willis (37.1%). The most common finding was the absence of the posterior communicating artery (32%), followed by posterior cerebral arteries originated from the internal carotid artery (18%). There were no variations in the middle cerebral arteries. Accessory anterior cerebral arteries were present in 6%, and A1 segment hypoplasia was present in only 2% of the cases. Conclusion: Brazilian population variations are in accordance with the literature and there seems to be no difference between races in the variation of brain circulation.

variation in the circulus arteriosus: a case report

This article described a variation detected in the cerebral arteries. In general the right arteries were found larger than the left. The left vertebral artery was found very small. Both anterior cerebral arteries originated from the right internal carotid and there was a small connecting branch from the left internal carotid to the left anterior cerebral artery

Anatomical variations of the circle of Willis in males and females on 3D MR angiograms

The objective of the present work was to study the anatomical variations of the circle of Willis as regard its component vessels and their average diameters in a sample of adult Egyptians and to detect any sex-related differences in these variations. One hundred and twenty adult patients were observed [60 males and 60 females]. They all had problems unrelated to any ischemic or vascular diseases, so they were considered as healthy control, concerning the morphology of the circle of Willis. In addition, ten cadavers' brains were obtained from the Anatomy department, Faculty of Medicine Ain Shams University for examination of the circle of Willis and for detection of any variations. The anatomical variations of the anterior part, posterior part and completeness of the circle were inspected. Also, the diameters of all component vessels were assessed. The results indicated that, the anterior part of the circle was completed in 70% males and 75% females of the study sample. No statistically significant difference was detected between sexes. The most common variant of the anterior part was the single anterior communicating artery followed by the hypoplastic or absent anterior communicating artery. The posterior part of the circle was completed in 48% males and 58% females. The most common variant was the bilateral posterior communicating arteries, followed by the unilateral posterior communicating artery. An entirely complete circle was found only in 45% of the entire population; and it was higher in the females than in males. The vessels diameters were smaller in the females than in the males, except for the diameter of the posterior communicating artery. Cadavers' examination revealed six cases with complete circle, 3 cases of unilateral fetal posterior communicating and one case of absent posterior communicating artery. The present study showed the amazing great variability of the anatomy of the circle of Willis in asymptomatic persons. Nevertheless, there were no marked differences between both sexes in most of the components and the mean diameters of the circle. Therefore, these anatomical variations have to be considered during radiological interpretation and would be reported in the current anatomy text to be aware of all these normal variations

Outcome of patients of subarachnoid hemorrhage due to ruptured anterior communicating artery aneurysm after surgical clipping

This prospective study was done to determine the outcome of subarachnoid haemorrhage [SAH] due to ruptured anterior communicating artery [a Corn] aneurysm in 8 consecutive patients after craniotomy and clipping of the aneurysm. The study was conducted at Mayo Hospital, Lahore from September 1999 to January 2002. All patients presented with history and examination suggestive of SAH had CT scan brain as first radiological investigation. Patients of SAH were graded clinically according to Hung and Hess scale. After confirmation of diagnosis of SAH, four vessels cerebral angiography was done to localize site of aneurysm in patiens of Hunt and Hess grade I, II and III or after they improved to at least grade III. Craniotomy and clipping of aneursm was done only in patients with Hunt and Hess grade I, II and III. Maximum patients presented during 6th decade i.e., 38%. Male to female ratio was 6:2. Hunt and Hess grade I, II and III was observed in 5,2 and 1 patients respectively. Outcome was assessed according to G lasgow Outcome Scale [GOS]. Good outcome was present in 75% patients and moderate disability in 25%

Vertebro-basilar insufficiency due to carotid stenosis.

Two patients with internal carotid disease and normal/hypoplastic vertebro-basilar system presenting with symptoms of vertebrobasilar insufficiency are presented. The role of associated anomalies of the circle of Willis or major vessels in the pathogenesis of symptoms is highlighted.