[Normal Anatomy and Variants of the Anterior Cerebral and Anterior Communicating Arteries].

The anterior cerebral artery(ACA)and anterior communicating artery(AcomA), two important arteries of the cerebral hemisphere, are involved in various disorders, including aneurysms, steno-occlusive diseases, and arteriovenous shunts, among other such conditions. Additionally, these vessels contain normal variants associated with their embryology and development. The ACA particularly shows characteristic variants such as a persistent primitive olfactory artery and an infraoptic course, among other such variations, which is attributable to the fact that it is embryologically older than the middle and posterior cerebral arteries. Aneurysm formation is associated with these variants. Therefore, knowledge of the normal anatomy and variants is important for diagnosis and treatment of conditions involving these arteries. In this article, we describe the normal anatomy and variants of the ACA and AcomA, focused on their embryological development.

The anterior communicating artery variants: a meta-analysis with a proposed classification system.

Morphological and morphometric variants of the anterior communicating artery (AComA) have been described by multiple studies; however, a complete classification system of all possible morphological variants with their prevalence is lacking. The current systematic review with meta-analysis combines data from different databases, concerning the AComA morphological and morphometric variants (length and diameter). Emphasis was given to the related clinical implications to highlight the clinical value of their knowledge. The typical AComA morphology occurs with a pooled prevalence (PP) of 67.3%, while the PP of atypical AComA is 32.7%. The identified AComA morphological variants (artery's hypoplasia, absence, duplication, triplication, differed shape, fenestration, and the persistence of a median artery of the corpus callosum- MACC) were classified in order of frequency. The commonest presented variants were the AComA hypoplasia (8%) and the anterior cerebral artery (ACA) fusion (5.9%), and the rarest ones were the MACC persistence (2.3%), and the AComA triplication (0.7%). The knowledge of those variants is essential, especially for neurosurgeons operating in the area. Given the high prevalence of AComA aneurysms, an adequate and complete classification of those variants is of utmost importance.

Microsurgical anatomy of the anterior cerebral artery and the arterial supply of the cingulate gyrus.

PURPOSE: The cingulate gyrus is a potential surgical area to treat tumours, psychiatric diseases, intractable pain and vascular malformations. The aim of the study was to define the topographic anatomy and arterial supply of the cingulate gyrus located on the medial surface of the cerebral hemisphere. METHODS: We studied thirty-six hemispheres, each hemisected in the midsagittal plane. The vertical thickness of the cingulate gyrus was measured at the anterior commissure (AC), posterior commissure (PC), and genu levels of the corpus callosum. The branches of the anterior and posterior cerebral arteries supplying each zone were noted separately. The arterial pathways were transformed to digital data in AutoCAD to identify the condensation and reduction areas. RESULTS: The mean AC-PC distance was 27.17 ± 1.63 mm. The thinnest region was the genu level of the corpus callosum (10.29 mm). The superior internal parietal artery (SIPA), inferior internal parietal artery (IIPA) and pericallosal artery (PrCA) supplied all zones of the cingulate gyrus. The anterior zone received the greatest supply. The arterial condensation and reduction areas on both sides of cingulate gyrus and its x, y, and z coordinates specified. CONCLUSIONS: The target cingulotomy (TC) area was determined for anterior cingulotomy. The properties of the TC area are that the thinnest region of the cingulate gyrus is supplied relatively less than other areas and is close to the anterior cingulotomy areas in the literature. The arterial reduction area (ARA) was found to be suitable for corpus callosotomy in terms of avoiding haemorrhage.

Endoscopic endonasal surgical anatomy through the prechiasmatic sulcus: the key window to suprachiasmatic and infrachiasmatic corridors.

BACKGROUND: Classically, the transtuberculum and transplanum approaches have been utilized to reach the suprachiasmatic and infrachiasmatic corridors. The aim of this study was to provide a better understanding of the key endoscopic endonasal anatomy of the suprachiasmatic and infrachiasmatic corridors provided through selective removal of the prechiasmatic sulcus (SRPS). METHOD: A SRPS was performed in 16 sides of 8 alcohol-fixed head specimens. Twenty anatomical measurements were collected on the suprachiasmatic and infrachiasmatic corridors. The transplanum and transtuberculum approaches were also performed. RESULTS: In the suprachiasmatic corridor, the SRPS exposed the anterior communicating artery (AComm) and the post-communicating segment of the anterior cerebral arteries in all the cases, while the pre-communicating segment of the anterior cerebral arteries, recurrent arteries of Heubner, and fronto-orbital arteries were visualized in 75% (12/16), 31% (5/16), and 69% (11/16) of cases, respectively. In the infrachiasmatic corridor, the ophthalmic segment of the internal carotid artery and superior hypophyseal arteries were always visible through the SRPS. The mean width and height of the prechiasmatic sulcus were 13.2 mm and 9.6 mm, respectively. The mean distances from the midpoint of the AComm to the anterior margin of the optic chiasm (OCh) was 5.3 mm. The mean width of the infrachiasmatic corridor was 12.3 mm at the level of the proximal margin of the ophthalmic segment of the internal carotid artery. The mean distances from the posterior superior limit of the pituitary stalk to the basilar tip and oculomotor nerve were 9.7 mm and 12.3 mm, respectively. CONCLUSIONS: The SRPS provides access to the main neurovascular and cisternal surgical landmarks of the suprachiasmatic and infrachiasmatic corridors. This anatomical area constitutes the key part of the approach to the suprasellar area. To afford adequate surgical maneuverability, the transplanum or transtuberculum approaches are usually a necessary extension.

Anatomical description and variations of the anterior arterial brain circulation in Colombian cadaveric specimens / Descripción anatómica y variaciones de la circulación cerebral arterial anterior en especímenes cadavéricos colombianos

SUMMARY: Understanding microsurgical neuroanatomy is a fundamental part of the training of neurosurgeons. Notwithstanding the fact that throughout history the study in cadavers has been a fundamental part of training, the publication of these studies has never marked a trend, and in our country the available studies are limited. A descriptive anatomical study was carried out on 22 specimens regarding the anatomical arrangement of the anterior circulation arteries of the brain and the most frequent anatomical variants in the sample used. To this end, bilateral pterional and bifrontal approaches were performed, obtaining a total of 132 arteries, including supraclinoid internal carotid arteries (ICA), anterior cerebral arteries in their A1 segment (ACA), and middle cerebral arteries in their M1 segment (MCA). measurements in each of these segments were made and anatomical variants were documented. Out of 22 cadaveric specimens, 17 (77 %) were male. the mean age was 59 years (range 36-81 years). Internal carotid artery mean length was 12.73 and 12.86 in the right and left side respectively. Anatomical variants identified were hypoplasia of segment A1 in 1 (4.5 %) specimen, duplication in 1 (4.5 %) and trifurcation of segment M1 in 3 (13.6 %) specimens. A similarity was found between our data and data reported by literature, with some differences, especially in the anterior communicating artery.

RESUMEN: Entender la neuroanatomía microquirúrgica es una parte fundamental de la formación de los neurocirujanos. A pesar de que, durante la historia, el estudio en cadáveres ha sido parte fundamental del entrenamiento, no ha sido tendencia la publicación de estos estudios, y en nuestro país son limitados los que se encuentran. Se realizó un estudio descriptivo anatómico en 22 especímenes acerca de la disposición anatómica de las arterias de la circulación cerebral anterior y las variantes anatómicas más frecuentes en población colombiana. Para dicho objetivo se realizaron abordajes bilaterales pterionales, y bifrontales obteniendo un total de 132 arterias incluyendo las arterias carotídeas internas supraclinoideas (ACI), arterias cerebrales anteriores en su segmento A1 (ACA) y las arterias cerebrales medias en su segmento M1 (ACM), se realizaron mediciones en cada uno de estos segmentos y se documentaron las variantes anatómicas. De los 22 especímenes cadavéricos, 17 (77 %) eran masculinos, la edad media fue de 59 años (rango 36-81 años). La longitud media de la arteria carótida interna fue de 12,73 mm en el lado derecho y de 12,86 mm en el lado izquierdo. Las variantes anatómicas identificadas fueron hipoplasia del segmento A1 en 1 (4,5 %), duplicación de A1 en 1 (4,5 %) y trifurcación del segmento M1 en 3 (13,6 %) muestras. Se encontró una similitud entre nuestros datos y los reportados por la literatura, con algunas diferencias, especialmente en el segmento de la arteria comunicante anterior.

Anterior Cerebral Artery and Anterior Communicating Artery Variations: Assessment with Magnetic Resonance Angiography.

BACKGROUND: Although anterior cerebral artery (ACA) and anterior communicating artery (AcomA) variations have been frequently investigated by contrast-enhanced angiography, the number of studies performed with magnetic resonance angiography is quite low. Our aim in this study is to investigate ACA and AcomA variations with time of flight magnetic resonance angiography (TOF MRA). METHODS: Source and maximum intensity projection images of 581 adult patients (273 males, 308 females) who were scanned for intracranial arteries with the TOF MRA method were retrospectively analyzed. RESULTS: We found the typical configuration rate of the ACA and AcomA complex to be 40.6%. The most common structural anatomic variations out of typical configuration were AcomA aplasia (18.9%) and AcomA hypoplasia (17.9%), respectively. The least frequent variation that we found was duplicated AcomA (0.9%). When we examined gender comparatively, unilateral A1 segment aplasia was found to be higher in males and azygos ACA was found to be higher in females (P = 0.001 and P = 0.029, respectively). CONCLUSIONS: In this study, in which we used the TOF MRA technique, we detected high rates of anatomic variations of ACA and AcomA. This method, which is noninvasive, does not require contrast material and does not contain ionizing radiation, can be preferred especially in the evaluation of patients with kidney disease and contrast allergy.

Anatomical variants of anterior communicating artery complex. A study by Computerized Tomographic Angiography.

Advances in imaging techniques have led to the identification of normal variations and abnormalities of cerebral arteries. Although the anterior communicating artery complex (ACAC) variations are usually asymptomatic, their description is essential in the radiologic report, since they can have clinical relevance. The aim of this study is to describe arterial anomalies of the ACAC and their prevalence. A retrospective observational descriptive analysis of ACAC variations in Computerized Tomographic Angiography (CTA) was performed. All CTA (426 studies) obtained in our center from 2015 to 2017 were included. Presence of aneurysm was recorded and its relationship with arterial variants was analyzed with a Chi-square test. The most common variants found in our study are linked to the A1 segment (42.3%) of the anterior cerebral artery (ACA): absence: 10.6%, hypoplasia: 31.2%, fenestration: 0.5%. A2 segment variants were present in 15.3% (absence: 0.2%; hypoplasia 8.5%; Azygos artery: 1.4%; triple ACA: 5.2%). Anterior Communicanting Artery was typical in 92.5%, absent in 4.7%, double/fenestrated in 0.9%, triple in 0.2%, X-shape in 1.2% and Y-shape in 0.2%. Aneurysms were present in 10.7%. Anterior circulation aneurysm involved the 50% of patients with aneurysm. Although the 60.9% of them showed artery variants, they did not reach statistical significance (p = 0.6). In conclusion, the Anterior Communicating Artery Complex presents variations in its anatomy. The most common anterior circulation vascular variants are the hypoplasia and the absence of the A1 segment. There does not appear to be a clear association between intracranial aneurysms and anatomical variations.

Morphological evaluation of the distal medial striate artery. A study with cadaveric material / Evaluación morfológica de la arteria estriada medial distal. Un estudio con material cadavérico

Abstract Objective: To evaluate the morphology of the distal medial striated artery, taking into account biometric variables useful for clinical and surgical management. Methods: A descriptive transversal study was performed with a sample of brains, who underwent autopsy at the Institute of Legal Medicine and Forensic Sciences of Bucaramanga-Colombia, which were evaluated using the perfusion technique of vascular structures with polyester resin. Results: The distal medial striated artery was presented in 1.4% and 4.2% duplicated in the right and left hemispheres respectively. Agenesis was presented in 2.8% in the left hemisphere. Its origin was 44.6% of the anterior cerebral artery junction site with the anterior communicating artery and was observed in 6 cases (4.2%) presented with a common trunk with the orbitofrontal artery. The main qualitative finding was the sinuous trajectory that was observed in 57.7% on the right side and 45.1% in the left hemisphere. Also, an important alteration found at the biometric analysis was hypoplasia that could be related to the decreased blood supply to the basal nuclei. The diameter was 0.5 ± 0.2 mm and its total length was 20.3 ± 4.1 mm. Conclusions: The topographical knowledge of this structure determines the vulnerability of its morphology because it can complicate surgical procedures performed in the anterior segment of the arterial circle of the brain. Besides, the observed collateral circulation contributes to the blood supply and the perfect functionality of the subcortical nervous structures.

Resumen Objetivo: Evaluar la morfología de la arteria estriada medial distal, teniendo en cuenta variables biométricas útiles para el manejo clínico y quirúrgico. Métodos: Estudio descriptivo transversal con una muestra de cerebros que fueron sometidos a autopsia en el Instituto de Medicina Legal y Ciencias Forenses de Bucaramanga-Colombia, fueron evaluados mediante la técnica de perfusión de estructuras vasculares con resina de poliéster. Resultados: La arteria estriada medial distal se presentó en 1.4% y 4.2% duplicada en el hemisferio derecho e izquierdo respectivamente. Agenesia se presentó en 2.8% en el hemisferio izquierdo. Su origen fue 44.6% del sitio de unión de la arteria cerebral anterior con la arteria comunicante anterior y se observó en 6 casos (4.2%) que presentaban un tronco común con la arteria orbitofrontal. El hallazgo principal fue la trayectoria sinuosa que se observó en 57.7% en el lado derecho y 45.1% en el hemisferio izquierdo. También una alteración importante encontrada en el análisis biométrico fue la hipoplasia que podría estar relacionada con la disminución del suministro de sangre a los núcleos basales. El diámetro fue de 0.5 ±0.2 mm y su longitud total fue de 20.3 ±4.1 mm. Conclusiones: El conocimiento topográfico de esta estructura determina la vulnerabilidad de su morfología, porque puede complicar los procedimientos quirúrgicos realizados en el segmento anterior del círculo arterial del cerebro. Además, la circulación colateral observada contribuye al riego sanguíneo y al perfecto funcionamiento de las estructuras nerviosas subcorticales.

Morphological evaluation of the choroidal arteries. A direct anatomic study

The Anterior Choroidal Artery (AChA), the Lateral Posterior Choroidal (LPChA) and the Medial Posterior Choroidal Arteries (MPChA) provide blood supply to the choroid plexus of the lateral ventricle and third ventricle. The objective of this study was to evaluate the morphology of the choroidal arteries in 74 unclaimed male cadavers, who under-went necropsy at the Institute of Legal Medicine and Forensic Sciences of Bucaramanga, Colombia. The AChA originated from the Internal Carotid Artery (ICA) in 96.6% of the cases, with a length of 10.1 ± 1.5 mm and 15.2 ± 1.7 mm for its pre-optic and post-optic segments respectively and had a diameter of 0.6 ± 0.16mm. The AChA originated branches to the optic tract (5.2), the anterior and posterior segment of the uncus of the hippocampus (3.4 and 2.4) and cerebral peduncles (2.6), before penetrating through the choroidal fissure. The MPChA originated from the pre-communicating segment of the posterior cerebral artery (ACP) in 97 cases (70.3%), its length was 38.1 ± 5.85 mm and its diameter 0.4 ± 0.14 mm; in three cases (2.2%) it was doubled. 46.3% of the MPChA presented proximal bifurcation at 8.7 ± 5.47 mm of their ACP origin, but in 17 cases (26.6%) an early bifurcation was found (less than 5 mm). The LPChA originated in the post-communicating segment (94.2%), without significant differences in presentation side (p = 0.189). Its length was 37.6 ± 7 mm and its diameter 0.5 ± 0.16 mm. The findings related to the site of origin, global dimensions and branches of the choroidal arteries observed in the present study are consistent with those reported in other population groups. This study, carried out in cadaveric material, provides relevant qualitative and morphometric information of the choroidal arteries, useful for diagnosis and clinical management, as well as for surgical approaches that may compromise this structure

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Comparative Analysis of Pterional, Supraorbital, Extended Supraorbital, and Transtubercular-Transplanum Approaches for Exposing the Anterior Communicating Artery Complex: A Cadaveric Study.

OBJECTIVE: We aimed to quantify and compare surgical exposure and freedom at the anterior communicating artery (ACoA) complex using pterional (PT), supraorbital (SO), extended supraorbital withorbital osteotomy (SOO), and endonasal endoscopic transtubercular-transplanum (EEATT) approaches. METHODS: Right-sided PT, SO, SOO, and EEATT approaches were performed using 10 cadaveric heads. Surgical exposure and freedom (horizontal and vertical attack angle) at the ACoA complex were measured. The farthest clipping distance from ACoA to A1 (precommunicating segment of the anterior cerebral artery)/A2 (postcommunicating segment of the anterior cerebral artery) was also quantified. RESULTS: There was a significantly greater exposure length of right A1 in the PT approach (12.20 ± 2.48 mm) compared with the EEATT approach (9.52 ± 2.09 mm; P = 0.029). Among the 4 approaches, EEATT provided the shortest clipping distance for right A1 (6.56 ± 1.33 mm; P = 0.001) and the longest clipping distance for right A2 (3.36 ± 1.24 mm; P = 0.003). SO, SOO, and PT approaches (2.9 ± 0.9) had more observations on perforators from ACoA than did the EEATT approach (2.0 ± 0.66; P = 0.029). The EEATT approach (50.90 ± 17.45 mm2) provided better exposure of the superior part of the ACoA complex compared with the SO approach (29.37 ± 17.27 mm2; P = 0.05). PT and SOO approaches provided the greatest horizontal (36.88° ± 5.85°) and vertical (19.37° ± 4.70°) attack angle, respectively. CONCLUSIONS: The SO, SOO, and PT approaches provided a better hemilateral view of the ACoA complex and similar surgical exposure, whereas the EEATT approach offered greater exposure in the upper part of the ACoA complex, with relatively limited exposure of perforators from ACoA and surgical freedom. The EEATT approach can play a role in exposure of lesion involving the ACoA complex.

Clinical and morphological risk factors for the recurrence of anterior communicating artery aneurysms after clipping or coiling.

BACKGROUND: The aim of this study was to evaluate clinical and morphological factors associated with recurrence in anterior communicating artery (AcomA) aneurysms after clipping or coiling. METHODS: We retrospectively reviewed the clinical and radiologic features of consecutive 214 patients with AcomA aneurysms treated between January 2012 and December 2016 in a single tertiary institute. Univariate and multivariate analyses were performed to identify the relationship between clinical and morphological variables and recurrence. RESULTS: Of 214 patients, 166 were unruptured aneurysms and 109 were treated with coiling. Overall recurrence rate was 13% (28 out of 214 aneurysms) during mean 36.9 ± 18.4-month follow-up. Multivariate logistic regression analysis showed that size greater than 10 mm (OR = 5.651; 95% CI, 1.317-24.242; p = 0.020), smoking (OR = 3.474; 95% CI, 1.342-8.996; p = 0.010), coiling (OR = 2.98; 95% CI, 1.005-8.832; p = 0.049), and anterior direction of aneurysm (OR = 3.77; 95% CI, 1.12-12.66; p = 0.032) were significantly associated with recurrence of AcomA aneurysms after treatment. CONCLUSIONS: The results of this study demonstrated that coiling, large aneurysm, anterior direction, and smoking history may be independent risk factors for the recurrence of AcomA aneurysms. Therefore, careful follow-up should be needed especially in large AcomA aneurysms with anterior direction after coiling.

Embryology and variations of the recurrent artery of Heubner.

PURPOSE: The recurrent artery of Heubner (RAH) is a very fascinating artery for various reasons. The first one is its early development in the embryologic and phylogenic life. The second one is the discrepancy between its diameter and its functional importance and the last but not least reason is the many variations of origin and course of this artery. METHODS: For more than a century, numerous studies furnished important information about variations in origin, course, and parenchymal territory of the RAH. The most important anomaly concerning the RAH is the accessory middle cerebral artery and well-illustrates the complexity of its embryologic development. CONCLUSION: For these reasons, authors provide a review of anatomical variations of this artery that could be encountered with a particular attention given to the history and embryological knowledge.

Morphological evaluation of the distal medial striate artery. A study with cadaveric material.

OBJECTIVE: To evaluate the morphology of the distal medial striated artery, taking into account biometric variables useful for clinical and surgical management. METHODS: A descriptive transversal study was performed with a sample of brains, who underwent autopsy at the Institute of Legal Medicine and Forensic Sciences of Bucaramanga-Colombia, which were evaluated using the perfusion technique of vascular structures with polyester resin. RESULTS: The distal medial striated artery was presented in 1.4% and 4.2% duplicated in the right and left hemispheres respectively. Agenesis was presented in 2.8% in the left hemisphere. Its origin was 44.6% of the anterior cerebral artery junction site with the anterior communicating artery and was observed in 6 cases (4.2%) presented with a common trunk with the orbitofrontal artery. The main qualitative finding was the sinuous trajectory that was observed in 57.7% on the right side and 45.1% in the left hemisphere. Also, an important alteration found at the biometric analysis was hypoplasia that could be related to the decreased blood supply to the basal nuclei. The diameter was 0.5 ± 0.2 mm and its total length was 20.3 ± 4.1 mm. CONCLUSIONS: The topographical knowledge of this structure determines the vulnerability of its morphology because it can complicate surgical procedures performed in the anterior segment of the arterial circle of the brain. Besides, the observed collateral circulation contributes to the blood supply and the perfect functionality of the subcortical nervous structures.

OBJETIVO: Evaluar la morfología de la arteria estriada medial distal, teniendo en cuenta variables biométricas útiles para el manejo clínico y quirúrgico. MÉTODOS: Estudio descriptivo transversal con una muestra de cerebros que fueron sometidos a autopsia en el Instituto de Medicina Legal y Ciencias Forenses de Bucaramanga-Colombia, fueron evaluados mediante la técnica de perfusión de estructuras vasculares con resina de poliéster. RESULTADOS: La arteria estriada medial distal se presentó en 1.4% y 4.2% duplicada en el hemisferio derecho e izquierdo respectivamente. Agenesia se presentó en 2.8% en el hemisferio izquierdo. Su origen fue 44.6% del sitio de unión de la arteria cerebral anterior con la arteria comunicante anterior y se observó en 6 casos (4.2%) que presentaban un tronco común con la arteria orbitofrontal. El hallazgo principal fue la trayectoria sinuosa que se observó en 57.7% en el lado derecho y 45.1% en el hemisferio izquierdo. También una alteración importante encontrada en el análisis biométrico fue la hipoplasia que podría estar relacionada con la disminución del suministro de sangre a los núcleos basales. El diámetro fue de 0.5 ±0.2 mm y su longitud total fue de 20.3 ±4.1 mm. CONCLUSIONES: El conocimiento topográfico de esta estructura determina la vulnerabilidad de su morfología, porque puede complicar los procedimientos quirúrgicos realizados en el segmento anterior del círculo arterial del cerebro. Además, la circulación colateral observada contribuye al riego sanguíneo y al perfecto funcionamiento de las estructuras nerviosas subcorticales.

Morphometric evaluation of Anterior Cerebral Artery (on Digital Subtraction Angiography)-Potential implications.

PURPOSE: The aim of the present study was to perform a morphometric analysis of ACA and to establish significant differences, if any, with sex and age via Digital Subtraction Angiography (DSA). METHODS: This cross-sectional study was conducted on 70 patients (>20 years) for the evaluation of ACA by Digital Subtraction Angiography done on a Philips biplane system clarity (Allura FD20/20). Length and diameter of ACA were taken manually on the DSA console using auto-calibration. Statistical analysis was done. RESULT: Mean diameter and length of ACA was found to be greater in female. The f-ratio value for diameter and length of the same was 1.43 and 0.92 respectively. The length of ACA was found to be statistically significant for different age groups. The mean length of ACA followed a decreasing trend with age, whereas mean diameter of ACA was nearly the same in all the age groups. CONCLUSION: The results of our study show that the length of ACA was found to be statistically significant for different age groups.

Circle of Willis anomalies in Turner syndrome: Absent A1 segment of the anterior cerebral artery.

PURPOSE: Turner syndrome (TS) is the most common sex chromosome disorder in women and is associated with a higher than expected death rate secondary to cerebrovascular disease, including stroke. This study evaluates the cerebral vascular anatomy of individuals with TS. METHODS: Twenty-one women with TS had brain magnetic resonance angiography (MRA). These MRAs were evaluated in a blinded manner with a control group of 25 men and 25 women who had MRA imaging for multiple indications including migraine headaches, psychiatric disorders, and seizures. RESULTS: Twenty-nine percent of women with TS were missing an A1 segment of the anterior cerebral artery (ACA) compared to 0% in the control group (p < .001). There were no other significant differences in the circle of Willis (COW) in women with TS compared with the control group. A complete COW was found in 3 of 21 (14%) of women with TS and 12 of 47 (26%) controls (p = .36). CONCLUSION: Women with TS have a significantly different intracranial vascular anatomy, specifically the absence of the A1 segment of the ACA when compared to male and female controls. More research in brain imaging in women with TS and stroke and other cerebrovascular diseases is needed to determine the clinical significance of this anomaly.

Prevalencia de la arteria estriada medial distal en una muestra de poblaciones Colombiana y Peruana / Prevalence of distal medial striatal artery in a sample of Colombian and Peruvian populations

La arteria estriada medial distal hace parte de la circulación encefálica, nace de la arteria cerebral anterior generalmente a nivel de la arteria comunicante anterior, aunque según distintos estudios su origen varía, siendo así difícil de determinar con exactitud. Su importancia clínica radica en la prevalencia de aneurismas encontrados en esta arteria, que posteriormente podrían causar complicaciones debido a la región que irrigan, siendo estas las secuelas somático-vitales y neuropsicológicas, además de su inadecuado abordaje quirúrgico sin prever las alteraciones que puedan ser ocasionados; a causa de lo anterior es de vital importancia que los profesionales de la salud tengan previo conocimiento de la anatomía y la prevalencia de esta arteria en la población. Se realizó un estudio observacional de tipo descriptivo en donde se analizó la arteria estriada medial distal en 70 encéfalos, piezas de los anfiteatros de Medicina de la Universidad de Ciencias Aplicadas y Ambientales U.D.C.A. (Bogotá), la Universidad Científica del Sur UCSUR (Lima); fijados en formol al 10 %, se realizaron mediciones morfométricas mediante calibrador digital y se tomó el registro fotográfico con una cámara Canon. Posteriormente se ejecutó el análisis estadístico mediante el programa IBM SPSS Stadistics 24. Se encontró una prevalencia del 88,6 % de al menos una arteria estriada medial distal en población colombiana y un 97,1 % de la población peruana. Se identificó un diámetro externo promedio de 0,64 mm en población colombiana y de 0,68 mm en población peruana. Se observó una longitud promedio de 2,5 cm en ambas poblaciones. Se evidenció el mayor lugar de origen en la porción A2 de la ACA con un 37,1 % de población colombiana y un 51,4 % de población peruana. Se debe conocer adecuadamente la anatomía y las correspondientes variaciones anatómicas de esta arteria para así poder realizar un adecuado abordaje neurológico y neuroquirúrgico.

The distal medial striate artery is part of the brain circulation, born from the anterior cerebral artery generally at the level of the anterior communicating artery, although according to different studies its origin varies, being thus difficult to determine with accuracy. Its clinical importance lies in the prevalence of aneurysms found in this artery, which could later cause complications due to the region they irrigate, these being the somatic-vital and neuropsychological sequelae, in addition to its inadequate surgical approach without foreseeing the alterations that may be caused; Because of the above it is of vital importance that health professionals have prior knowledge of the anatomy and prevalence of this artery in the population. An observational descriptive study was carried out in which the distal medial striated artery in 70 brain cells, pieces from the Medicine amphitheatres of the Universidad de Ciencias Aplicadas y Ambientales U.D.C.A. (Bogotá), the Universidad Científica del Sur UCSUR (Lima); fixed in 10 % formalin, morphometric measurements were made by automatic calibrator and the photographic record was taken with a Canon camera. Subsequently, the statistical analysis was executed through the IBM SPSS Statistics program 24. A prevalence of 88.6 % of at least one distal medial striate artery was found in the Colombian population and 97.1 % of the Peruvian population. An average external diameter of 0.64 mm was identified in the Colombian population and 0.68 mm in the Peruvian population. An average length of 2.5 cm was observed in both populations. The largest place of origin was evidenced in the A2 portion of the ACA with 37.1 % of the Colombian population and 51.4 % of the Peruvian population. The anatomy and the corresponding anatomical variations of this artery must be adequately known to be able to perform an adequate neurological and neurosurgical approach.

Microsurgical anatomy of the subcallosal artery.

BACKGROUND AND PURPOSE: The subcallosal artery [SCA, a branch of the anterior communicating artery (ACoA)] is not well described in the literature. However, the memory disorders that can occur after surgical repair of ruptured ACoA aneurysms might be related to infarction of the SCA. The objective of the present study was to perform a thorough anatomical assessment of the SCA. METHODS: The study was carried out over a 6-month period in a University Hospital's anatomy laboratory, using brains extracted from human cadavers. The brains were injected with colored neoprene latex and dissected to study the SCA's origin, path, termination, diameter, length, and vascularized territories. RESULTS: 21 cadaveric specimens were studied. The mean ± standard deviation diameter and length of the SCA were 0.83 ± 0.57 mm and 38.14 ± 25.11 mm, respectively. The predominantly vascularized territories were the paraterminal gyrus (100%), the parolfactory gyrus (78.95%), the rostrum (84.21%) and genu (78.95%) of the corpus callosum, the lamina terminalis (78.95%), the anterior commissure (63.16%), the anterior cingulate gyrus (47.37%), and the fornix (26.32%). When the SCA supplied the fornix and the anterior cingulate gyrus, it was significantly longer and broader (p < 0.05). CONCLUSION: Anatomic knowledge of the SCA is crucial-especially for the treatment of ACoA aneurysms.

Increased tortuosity of ACA might be associated with increased risk of ACoA aneurysm development and less aneurysm dome size: a computer-aided analysis.

OBJECTIVES: We decided to perform computer-aided analysis of the anterior cerebral artery (ACA) to check for a potential correlation with anterior communicating artery (ACoA) aneurysm presence and growth. METHODS: We retrospectively analyzed the ACA anatomy of 121 patients with ACoA aneurysms along with 121 age, risk factors, and vessel side-matched control patients without an ACoA aneurysm. We obtained their medical history and digital subtraction angiography (DSA) data from their medical records. For each patient's DSA, we extracted curve representing the course of their ACA and calculated its relative length (RL), sum of angle metrics (SOAM), triangular index (TI), product of angle distance (PAD), and inflection count metrics (ICM). RESULTS: Patients with ACoA aneurysm had significantly higher RL (0.64 ± 0.23 vs. 0.56 ± 0.22; p < 0.01), SOAM (0.27 ± 0.19 vs. 0.18 ± 0.15; p < 0.01), PAD (0.12 ± 0.13 vs. 0.09 ± 0.11; p = 0.02), and TI (0.57 ± 0.14 vs. 0.44 ± 0.15; p < 0.01). In multivariate logistic regression analysis, after adjustment for possible confounders, SOAM (OR, 1.34; 95% CI, 1.12-1.63; p < 0.01) and TI (OR, 1.84; 95% CI, 1.47-2.35; p < 0.01) remained independently associated with higher risk of ACoA aneurysm. Additionally, we found significant negative correlations between TI and aneurysm dome size (R = - 0.194; p = 0.047). CONCLUSIONS: Increased tortuosity of ACA might increase the risk of ACoA aneurysm development and decrease the risk of aneurysm growth. KEY POINTS: • Anterior cerebral artery's sum of angle metrics is associated with hypertension as well as with history of ischemic stroke and myocardial infarction. • Increased tortuosity of anterior cerebral artery might be associated with anterior communicating artery aneurysm development. • Tortuosity of anterior cerebral artery is negatively correlated with anterior communicating artery aneurysm dome size.

Proximal Branches of the Anterior Cerebral Artery: Anatomic Study and Applications to Endoscopic Endonasal Surgery.

BACKGROUND: The endoscopic endonasal approach is a surgical alternative for midline anterior skull base tumors. A detailed understanding of the proximal anterior cerebral artery (ACA) branches' anatomy from an endonasal perspective is essential for avoiding vascular complications. OBJECTIVE: To evaluate, from an endonasal perspective, the anatomic variations of the ACA and its proximal branches, specifically the recurrent artery of Heubner (RAH), and the fronto-orbital (FOA) and frontopolar (FPA) arteries. METHODS: We study the origin, course, branching pattern, diameter, and relationship between the proximal ACA branches and the optic apparatus and olfactory tract in 25 head specimens. RESULTS: The RAH was present in all hemispheres and originated within 3 ± 1.5 mm of the AcomA, with a 0.4 ± 0.1 mm diameter. Based on its relationship with the A1 segment, we observed three RAH courses: anterior (40%), superior (22%), and posterior (38%). The FOA was present in all cases, a mean of 6 ± 4 mm from the AcomA, with a 0.7 ± 0.4 mm diameter. The FOA arose mainly from the A2 (70%), with three courses in relation to the olfactory tract: crossing its proximal third (54%), crossing its middle third (31%), and running parallel to it along the gyrus rectus (15%). The FPA was present in 92% of the hemispheres, a mean of 10 ± 5 mm from the AcomA, always arising from the A2 and coursing anteriorly within the interhemispheric fissure towards the frontal pole. CONCLUSION: The RAH, FOA, and FPA can be differentiated by origin, course, and destination using the A1 segment, olfactory tract, and interhemispheric fissure, respectively, as surgical landmarks.

Internal Maxillary Artery to Anterior Circulation Bypass with Local Interposition Grafts Using a Minimally Invasive Approach: Surgical Anatomy and Technical Feasibility.

BACKGROUND: The internal maxillary artery (IMA) is a reliable donor for extracranial-intracranial high-flow bypasses. However, previously described landmarks and techniques to harvest the IMA are complex and confusing and require extensive bone drilling, carrying significant neurovascular risk. The objective of our study was to describe a minimally invasive technique for exposing the IMA and to assess the feasibility of using the IMA as a donor for anterior-circulation recipient vessels using 2 different local interposition vessels. METHODS: Via a minimally invasive technique, the IMA was harvested in 10 cadaveric specimens and a pterional craniotomy was performed. Two interposition grafts-the superficial temporal artery (STA) and middle temporal artery-were evaluated individually. Transsylvian exposure of the second segment of middle cerebral artery (M2), the supraclinoid internal carotid artery, and the proximal postcommunicating anterior cerebral artery segment was completed. Relevant vessel calibers and graft lengths were measured for each bypass model. RESULTS: The mean caliber of the IMA was 2.7 ± 0.5 mm. Of all 3 recipients, the shortest graft length was seen in the IMA-STA-M2 bypass, measuring 42.0 ± 8.4 mm. There was a good caliber match between the M2 (2.4 ± 0.4 mm) and STA (2.3 ± 0.4 mm) at the anastomotic site. The harvested middle temporal artery was sufficient in length in only 30% cases, with a mean distal caliber of 2.0 ± 0.7 mm. CONCLUSIONS: This study confirmed the technical feasibility of IMA as a donor for an extracranial-intracranial bypass to the second segment of the anterior cerebral artery, M2, and the supraclinoid internal carotid artery. However, IMA-STA-M2 was observed to be the most suitable bypass model.