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.

Variants in the circle of Willis and white matter disease in Ecuadorian Mestizos.

BACKGROUND AND PURPOSE: Studies on Whites and Asians have shown contradictory results on the association between an incomplete circle of Willis (CoW) and white matter disease (WMD). We evaluated such relationship in Ecuadorian Mestizos. METHODS: Ecuadorian Mestizos aged ≥40 years were evaluated with MRI and MRA. WMD was graded according to the modified Fazekas' scale, and the CoW was classified as complete or incomplete according to the presence or absence of one A1 segment of the anterior cerebral artery or one or both P1 segments of posterior cerebral arteries. RESULTS: A total of 315 persons (mean age 64.7 ± 13.4 years, 56.5% women) were prospectively enrolled over 6 months. MRAs revealed a complete CoW in 65.1%, and MRIs showed WMD in 62.5% of cases. Irrespective of age and sex, incompleteness of the CoW was not associated with a higher prevalence or severity of WMD. In contrast, age was an independent risk factor for the occurrence of WMD. CONCLUSIONS: In the Ecuadorian Mestizo population, WMD occurrence and severity do not seem to be related to incompleteness of the CoW.

Incompleteness of the Circle of Willis correlates poorly with imaging evidence of small vessel disease. A population-based study in rural Ecuador (the Atahualpa project).

BACKGROUND: Studies looking for an association between incompleteness of the Circle of Willis (CoW) and small vessel disease (SVD) markers are scarce and conflicting. We aimed to evaluate this association in an unbiased population-based study conducted in Atahualpa (rural Ecuador). METHODS: Atahualpa residents 60 years of age or more were identified during a door-to-door survey and invited to undergo magnetic resonance imaging for identification of SVD markers, including white matter hyperintensities (WMHs), strokes, and deep microbleeds. Magnetic resonance imaging (MRA) was used for classifying the CoW according to the presence or absence of one A1 segment of the anterior cerebral artery or one or both P1 segments of posterior cerebral arteries. RESULTS: Of 311 eligible persons, 258 were enrolled. Mean age was 70 ± 8 years, 59% were women, and 74% had a poor cardiovascular health (CVH) status. Of these, 172 patients (67%) had WMH, 40 patients (16%) had SVD-related strokes, and 23 patients (9%) had deep microbleeds. MRA revealed a complete CoW in 157 persons (61%). Persons with SVD markers were older than those without markers (P < .0001). A poor CVH status was noted in 79% of persons with at least 1 SVD marker and in 65% of those with no markers (P = .02). Logistic regression models showed no association of incompleteness of the CoW with any marker of SVD-alone or in combination-after adjusting for age, sex, and CVH status. CONCLUSIONS: Lack of association between incompleteness of CoW and SVD markers suggest that genetically determined variants in the intracranial vasculature are not responsible for the high prevalence of SVD among native South American populations.

[Endovascular coiling of a «true¼ posterior communicating artery aneurysm]. / Tratamiento endovascular de un aneurisma «verdadero¼ de la arteria comunicante posterior.

True posterior communicating artery aneurysms originate exclusively from the wall of this artery and should be differentiated from aneurysms of the posterior communicating segment of the distal carotid artery. As these lesions are rare, their anatomical relationships have been poorly described; likewise, reports concerning their endovascular treatment are extremely rare and the technical aspects poorly detailed. A case of a patient with a true aneurysm of the left posterior communicating artery treated by endovascular coiling is presented. A literature review was also conducted to illustrate the anatomical and technical details relevant to achieving its successful treatment.

Prevalence and severity of atherosclerosis in different arterial territories and its relation with obesity.

BACKGROUND: There is uneven association between obesity, traditional risk factors, and cardiovascular events. We aimed to analyze the relation between cardiovascular risk factors, including obesity, with the severity of atherosclerosis in different arterial territories. METHODS: Arteries from five territories (circle of Willis, carotids, coronaries, aorta, and renal) were taken from 185 persons, newborn to 90 years undergoing autopsy in the Forensic Medical Service in Mexico City, to determine atherosclerotic lesions by histopathological study. Lesions were classified according to the American Heart Association grading system as early (types I-III) and advanced (types IV-VI). The degree of atherosclerosis was correlated with arterial territories and risk factors. RESULTS: Frequencies of advanced lesions according to arterial territories were as follows: circle of Willis, 28%; right carotid, 36%; left carotid, 25%; right coronary, 71%; left coronary, 85%; right renal, 26%; left renal, 29%; and aorta, 52%; P=.0001, for all analyses. There was a higher risk for advanced lesions with increasing body mass index (BMI) (P=.004). However, after adjusting for age, gender, smoking status, hypertension, and diabetes mellitus, BMI was not independently associated with advanced lesions. CONCLUSIONS: Coronary arteries are significantly more affected than other arterial territories regardless of risk factors, showing the effect of local and systemic factors in the severity of atherosclerosis. We did not find an independent association between advanced atherosclerotic lesions and obesity.

Epidermal growth factor and growth hormone-releasing peptide-6: combined therapeutic approach in experimental stroke.

PURPOSE: Stroke is the second cause of mortality worldwide, with a high incidence of disability in survivors. Promising candidate drugs have failed in stroke trials. Combined therapies are attractive strategies that simultaneously target different points of stroke pathophysiology. The aim of this work is to determine whether the combined effects of epidermal growth factor (EGF) and growth hormone-releasing peptide-6 (GHRP6) can attenuate clinical signs and pathology in an experimental stroke model. METHODS: Brain global ischemia was generated in Mongolian gerbils by 15 minutes of carotid occlusion. After reperfusion, EGF, GHRP6 or EGF+GHRP6 were intraperitoneally administered. Clinical manifestations were monitored daily. Three days after reperfusion, animals were anesthetized and perfused with an ink solution. The anatomy of the Circle of Willis was characterized. Infarct volume and neuronal density were analyzed. RESULTS: EGF+GHRP6 co-administration reduced clinical manifestations and infarct volume and preserved neuronal density. No correlation was observed between the grade of anastomosis of the Circle of Willis and clinical manifestations in the animals receiving EGF+GHRP6, as opposed to the vehicle-treated gerbils. CONCLUSIONS: Co-treatment with EGF and GHRP6 affects both the clinical and pathological outcomes in a global brain ischemia model, suggesting a suitable therapeutic approach for the acute management of stroke.

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.

Variaciones morfológicas del círculo arterial en fallecidos con enfermedades cerebrovasculares Isquémicas / Morphological variations of the arterial circle in the deceased with ischemic cerebrovascular disease

Se realiza un estudio con el objetivo de describir variaciones morfológicas del encéfalo en fallecidos por enfermedades cerebrovasculares isquémicas (ECVI) en el Hospital General Docente Dr Agostinho Neto de Guantánamo, en el período enero-junio de 2010. El universo está constituido por el total de fallecidos en dicha entidad hasta 2010 y, la muestra, por 134 encéfalos de individuos que al morir presentaron diagnóstico de ECVI. La información primaria es tomada de controles estadísticos, historias clínicas, libro de necropsias del hospital y plasmada en una ficha de vaciamiento. Se seleccionan variables como: edad, sexo, configuración del polígono de Willis y variaciones arteriales. Predomina el sexo masculino y el grupo de edades de 80-89, color de piel mestizo, así como círculos arteriales con modificaciones no clásicos, que en la mayoría de los individuos está dada por el aspecto delgado de las arterias, afectando fundamentalmente a la ACoP derecha. Se recomienda relacionar los resultados obtenidos en encéfalos de fallecidos por enfermedades cerebrovasculares isquémicas con los de fallecidos por otras causas (AU)

A research is done at the Microbiology lab of the Provincial Center of Hygiene Epidemiology and Microbiology (CPHEM) from January to March 2009 with the aim to determine antimicrobial resistance in 73 strains of microorganisms isolated and identified from sputum samples of patients with lower respiratory infections. Determine the sensitivity and resistance to antimicrobials in vitro by the Kirby Bauer method. The results are expressed in two-dimensional table and the summary measure was used by percentage. The highest number of bacteria was identified gram-negative bacilli. The greatest resistance is shown by the Pseudomonas aeruginosa, Staphylococcus aureus, followed by Klebsiella pneumoniae. As a conclusion antimicrobial resistance is an emerging problem, which requires the proper selection and identification of the etiologic agent

Carotid siphon geometry and variants of the circle of Willis in the origin of carotid aneurysms.

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.

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.

[Morphological characteristics of cerebral aneurysm of Willis' circle: a direct anatomical study]. / Características morfológicas de aneurimas cerebrales del polígono de Willis: estudio anatómico directo.

OBJECTIVE: To determine the prevalence and morphologic characteristics of unruptured aneurysms of Willis' circle in a sample of mestizo Colombian population. MATERIALS AND METHODS: A mixture of resin and mineral red was injected into cerebral arteries by dissection and canalization of common carotids and vertebral arteries of the encephalons of 125 mestizo male cadavers of 16 to 65 years old. The procedure was carried out during the autopsy course at the Legal Medicine Institute, Bucaramanga - Colombia. Then the encephalons were extracted and fixed. After that, the Willis' circles were identified and the presence of aneurysms at this level was determined with magnifying glass. RESULTS: A total of nine aneurysms were observed in six brains (4.8%). The most frequent location was the supraclinoid segment of the intern carotid artery, with 4 cases (44.4%), three of which were localized in the origin of the anterior choroidal artery. Additionally, three aneurysms were found in the anterior communicating artery (33.3%). From the remaining cases, one (11.1%) was localized in the pre-communicating segment of the anterior cerebral artery, and the other in the bifurcation of the basilar artery. The average size of the aneurysms was 2.49 mm SD 0.37. The affected encephalons presented concomitant variations of the Willis' circle configuration, being predominant the presence of hypoplasic posterior communicanting arteries. CONCLUSION: The aneurysm prevalence in the evaluated sample was similar to the reported in other populations. In this work, the presence of aneurysms on the origin of the anterior chorioid artery, an unusually reported localization, was prominent.

Unilateral pterional approach to bilateral aneurysms of the middle cerebral artery.

BACKGROUND: The aim of the present study was to evaluate the technical viability of the unilateral pterional approach to simultaneously treat symmetrical bilateral aneurysm (mirror image) of the middle cerebral arteries (SBAMCA) and to determine the morbidity and mortality rates of this approach. METHODS: Forty-six patients with SBAMCA underwent unilateral pterional craniotomy within a period of 9 years. Most patients were women (24, 80.0%) and mean age was 40.7 years. RESULTS: Obliteration of the contralateral aneurysm was not possible in 16 patients (34.8%) because of brain edema in 8 patients operated on during the acute phase, lateral projection of the aneurysm in 3, a very long contralateral M1 segment in 4, and the presence of atheromatous plaques at the MCA bifurcation and aneurysm neck in 1. The remaining 30 patients (65.2%) were submitted to the proposed treatment. Final evaluation showed that 26 patients (86.7%) were Glasgow Outcome Scale (GOS) V, 1 patient (3.3%) was GOS IV, 2 patients (6.6%) were GOS III, and 1 patient (3.3%) was GOS I. CONCLUSIONS: The unilateral pterional surgical approach to treat SBAMCA is a technically viable procedure associated with low morbidity and mortality. However, it requires a neurosurgeon experienced in cerebral aneurysm surgery and the appropriate technical conditions.

Atherosclerotic lesion of the circle of Willis: its study applying an atherometric system using multivariate statistical techniques.

In 2043 autopsies divided into the high (HAG) and low (LAG) atherosclerosis group a set of variables of a new atherometric system (AS) was used to characterize the atherosclerotic lesion (AL) in the circle of Willis arteries: fatty streaks (X), fibrous plaques (Y), severe plaques (Z), index of stenosis (P) and index of benignity (B). Principal component analysis identified a first component of severity (Y, P and Z) and a second component of benignity (X and B). Fibrous plaques play the main role in the severity of AL in the circle of Willis. The new AS proved its usefulness in characterizing the state of AL, whereas discriminant analysis and AS distinguished between the HAG and the LAG. The classification was correct in 74.5% and 76.5% when using three (X, Y, Z) and five (X, Y, Z, P, B) variables, respectively.

Atherometric system: morphometric standardized methodology to study atherosclerosis and its consequences.

A group of strong mutual dependent variables, obtained by measuring some morphological and pathomorphological characteristics of an artery affected by atherosclerosis (arterial variables) and its organ-related damage (organ-related variables DRV), yield a suitable methodology to study and characterize this disease and its further severe consequences. Applying some biophysical (rheological, geometrical, and haemodynamical) and mathematical reasonings to those measurements an atherometric system AS is derived. It is a new standardized morphometric methodology which allows, by the use of their variables, the development of useful pathomorphological, pathogenetical, statistical, and epidemiological investigations. The variables of the AS are divided into 1. descriptives and 2. weighting indices WI to estimate the severity of atherosclerosis. The descriptive arterial variables were obtained from each type of atherosclerotic lesion AL, fatty streak, fibrous plaque, and severe (complicated and calcified) plaques, latter normalize and further represented in a 3-dimensional vector, in order to conserve all the analytical information of each type of AL. Their WI are obstruction, stenosis, and benignity. The descriptives DRV (estimated volumes) and their respectively derived WI, are in relation with the pathological conditions: fibrosis, necrosis, haemorrhage, total damage, and their counterpart non-affected (sufficient) variables. A digitizer coupled to a personal computer LTEL (Cuba) to obtain the primary data was used. All data were processed in a computer EC-1040 (G.D.R.) using the statistical commercial package "SPSS" for scientific analysis.

[Frequency of potential anastomoses in the posterior communicating branches of the circle of Willis]. / Frequência de anastomoses potenciais nos ramos comunicantes posteriores do círculo arterial do cérebro.

This neuroanatomic study has been performed to establish the frequency of potencials anastomosis in the posterior portion of the cerebral arterial circle in 87 brains from northeasterner brazilians without any aparent clinical manifestations of neural dysfunction. The fetal pattern of the posterior communicating branch was present in the 46% (40/87) of the cases. The frequency with regard to side was the following: 21,8% (19/87) on the right side; 12,8% (12/87) on the left side and 10,4% (9/87) bilateral. The bilateral and unilateral potencials anastomosis at level of the posterior communicating branches, with fetal pattern or with gross caliber (Padget, 19483), were present in the 71,2% (62/87) of the arterial circles. The bilateral potencials anastomosis were formed by two posterior communicating branches with fetal pattern in the 10,4% (9/87) of the cases, by two of those vessels of gross caliber in the 11,5% (10/87) of the circles, and by one fetal posterior communicating branch, and one contralateral posterior communicating branch of gross caliber in the 13,8% (12/87) of the cases. Unilateral potencials anastomosis constituted by fetal posterior communicating branch (21,8%) or by posterior communicating branch with gross caliber (13,8%) ocurred in the 35,6% (31/87) of the arterial circles.