[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.

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.

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.

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.

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.

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.

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.

Operative Management of Distal Anterior Cerebral Artery Aneurysms Through a Mini Anterior Interhemispheric Approach.

BACKGROUND: Distal anterior cerebral artery (DACA) aneurysms, also known as pericallosal artery aneurysms, are present in 1.5%-9% of all intracranial aneurysms. Here we characterize the important microsurgical anatomy of DACAs; describe the surgical approach to treating these aneurysms with a minimally invasive surgical technique, the mini anterior interhemispheric approach (MAIA); and examine the nuances of aneurysm clipping in this region. METHODS: This was a retrospective and descriptive analysis of a series of aneurysm surgeries performed at the National Institute of Neurology and Neurosurgery in Mexico City. Cadaveric dissections were used to demonstrate relevant cerebrovascular anatomy. We analyzed patient demographic data and aneurysm characteristics. Patients' neurologic grade was evaluated using the Hunt and Kosnik (H-K) scale, and surgical outcomes were evaluated using the Glasgow Outcome Scale (GOS). Other variables were analyzed using the χ2 test. RESULTS: We analyzed a total of 32 DACA aneurysms (10 nonruptured and 22 ruptured), representing 5.8% of all aneurysms. The study cohort was 64.3% females and 35.7% males. H-K grade II was the most frequent classification (32.4%); 42.8% of patients presented with a Fisher grade IV aneurysm. Aneurysm location was classified as supra-genu, genu, or infra-genu. Eight patients had multiple aneurysms, among which 50% were located at the bifurcation of the middle cerebral artery. CONCLUSIONS: Surgical clipping through a MAIA approach is an excellent treatment option for pericallosal artery aneurysms.

Split-brain phenomena in anterior communicating artery aneurysm rupture: A case report.

In 1976, a patient with an anterior communicating artery aneurysm (ACoAA) rupture (diagnosed on angiography) and sub-arachnoid hemorrhage (SAH) underwent serial neuropsychological testing revealing a classical anterior cerebral artery (ACA) spasm picture with severe anterograde amnesia of Korsakoff's type and dysexecutive syndrome. In addition, the patient demonstrated impaired hemispheric interaction with alien hand syndrome, dyscopia-dysgraphia, complete left ear neglect, and other, more complex, split-brain phenomena. He was evaluated by A. R. Luria in 1976. Following surgery the patient demonstrated gradual improvement.

The Microsurgical Anatomy of the Orbitofrontal Arteries.

OBJECTIVE: The orbitofrontal (or frontobasal) arteries (OFAs) are the medial (MOFA) and lateral (LOFA) orbitofrontal artery, branches of the anterior and middle cerebral artery, respectively. They supply the orbitofrontal cortex. The purpose of this microscopic cadaveric study was the detailed and precise anatomic identification of the OFAs along their course. METHODS: Twenty formalin-fixed, colored latex-injected cadaveric heads were studied with the aid of an operating microscope and microsurgical instrumentation. The anatomy of the OFAs was examined after removing the cerebrum from the cranial vault. Anatomic features of the MOFA and LOFA were investigated and assessed in relation to demographic and anthropometric variables. RESULTS: The MOFA supplies approximately 15 branches and LOFA almost 16 branches. The MOFA provides 1 branch to the olfactory bulb and 4 branches to the olfactory tract, and there are approximately 2 MOFA-LOFA anastomoses per hemisphere (novel finding). The MOFA origin is located approximately 7.9 mm anterior to the anterior communicating artery and 4.7 cm posterior to the anterior limit of the gyrus rectus. The LOFA origin is located approximately 11.1 mm from the middle cerebral artery bifurcation. Younger, shorter, and lighter individuals have more MOFA-LOFA anastomoses. Finally, the number of MOFA branches for the olfactory bulb is positively correlated with the number of MOFA branches for the olfactory tract, as well as with the number of MOFA-LOFA anastomoses. CONCLUSIONS: The present study provides a detailed description of the OFAs' microsurgical anatomy and can help neurosurgeons to easily identify, manipulate, and preserve these vessels during surgery.

Angiographic Morphometry of Internal Carotid Artery Circulation in Turkish Children.

AIM: Knowledge of cerebrovascular morphology is integral in planning neuroendovascular interventions, especially for procedures involving placement of stents, flow diverters or stentrievers. There is insufficient data on angiographic normative values of cerebral circulation in the pediatric age group since angiograms are uncommonly performed in children except for arteriovenous malformations in which arterial dimensions are larger than normal. We aimed to measure the diameters of internal carotid circulation (ICC) arteries on digital subtraction angiograms of pediatric patients and determine the growth trends. MATERIAL AND METHODS: This is a retrospective cross-sectional study measurements of ICC arteries of 64 pediatric patients (4-122 months) with retinoblastoma undergoing intra-arterial chemotherapy. RESULTS: Petrous, cavernous, supraclinoid and choroidal segments of internal carotid artery (ICA) and anterior cerebral artery (ACA) diameters had significant correlation with age. Most of the growth was noted in the first 36-48 months of life. Middle cerebral artery (MCA) diameter did not show significant correlation with age. 87% of the adult diameter of the MCA was attained in the first 6 months of life. ICC arteries reached 81% to 99% of adult sizes in the first 48 months of life. On the contrary, the main iliac artery was only 59% of the adult diameter at this age group. CONCLUSION: Use of current intracranial stents in children appears tolerable due to the growth pattern of ICC arteries. Based on this data, the current armamentarium of intracranial stents or stent-like devices is sufficient to cover the need in the pediatric population.

The extended endoscopic endonasal transplanum transtuberculum approach to the anterior communicating artery complex: anatomic study.

BACKGROUND: When performing a transplanum transtuberculum approach, dealing with the anterior communicating artery (ACoA) complex is inevitable. The aim of this study is to provide quantitative anatomical information regarding the ACoA complex and its bony and neural relationships, when exposed through this approach. METHOD: The endoscopic endonasal transplanum transtuberculum approach was performed on ten human cadaver heads. In each specimen, radiological studies were performed. A three-dimensional model of the approach was reconstructed. Measured parameters were: exposure of the vessels; distance between the proximal anterior cerebral artery (A1) and the optic chiasm; dimension of the bone opening. The feasibility to perform clip placement was graded as "possible" or "not possible". RESULTS: Dimension of bone opening varied from 88 to 53 mm(2). The ACoA was exposed for 3 mm ± 2 mm, A1 for 17 mm ± 9 mm, the distal anterior cerebral artery (A2) for 12 mm ± 3 mm, the recurrent artery of Heubner (RAH) for 16 mm ± 4 mm. Clip placement was possible on the ACoA, A2, and distal segment of A1 in all cases, and on the proximal segment of A1 in one instance. The distance between A1 and the optic chiasm measured 9 mm ± 2 mm. CONCLUSIONS: The ACoA, A2, and the distal segment of A1 can be visualized and controlled through the transplanum transtuberculum approach. The relationship between A1, gyrus rectus, and optic chiasm is the main determinant for the exposure and control of the vessel. The olfactory nerve can represent a surgical landmark for the identification of the A1 origin. The whole course of the RAH can be visualized trough this approach.

Ophthalmic artery arising from the anterior cerebral artery diagnosed by MR angiography.

Extremely rarely, the ophthalmic artery (OphA) arises from the A1 segment of the anterior cerebral artery (ACA). Discovery of this anomalous OphA during angiography or surgery has been reported in several patients. We report a case in which an OphA of ACA origin was diagnosed by magnetic resonance (MR) angiography and confirmed by selective cerebral angiography. To our knowledge, this is the first report of this variation with MR angiography. Careful observation of MR angiographic images is important for detecting rare arterial variations. Partial maximum-intensity-projection images are useful in identifying tiny anomalous arteries on MR angiography.

[Microsurgical anatomy of perforating branches of anterior communicating artery]. / Anatomie microchirurgicale des branches perforantes de l'artère communicante antérieure.

INTRODUCTION: The anterior communicating artery (ACoA) gives perforating branches to the optic chiasma, the hypothalamus and the corpus callosum. Perforating branches are variable (number, direction). Nevertheless, their knowledge is crucial during surgery of this area to spare injuries leading to ischemic post-operative complications. OBJECTIVE: The objective was to update the anatomical knowledge about perforating branches of the ACoA. METHODS: The study was led on a series of seven brains taken from human cadavers. An injection of latex neoprene was performed for every case. The region of interest was observed under operating microscope. Were examined: the length of the ACoA, its diameter, its orientation, its configuration and perforating branches (number and areas). RESULTS: Three cases on five presented with an anatomical variation at the level of the ACoA. The average length of AcoA was 2.1 millimeters (min: 2, max: 2.2). The average diameter of the ACoA was 1.67 mm (min: 1.1, max: 2.1). The average number of perforating branches was 4.2 (min: 2, max: 6). The presence of a median artery of the corpus callosum seemed to correlated with a low number of perforating branches. Branches supplying the optic chiasma seemed to be more numerous.

Association of aneurysms and variation of the A1 segment.

BACKGROUND AND PURPOSE: Previous studies have described a correlation between variants of the circle of Willis and pathological findings, such as cerebrovascular diseases. Moreover, anatomic variations of the anterior cerebral artery (ACA) seem to correspond to the prevalence of aneurysms in the anterior communicating artery (ACoA). The aim of this study was to assess the prevalence of aneurysms in patients with anatomical/morphological variations of the circle of Willis. METHODS: We retrospectively analyzed 223 patients who underwent cerebral angiography between January 2002 and December 2010 for aneurysm of the ACoA. Diagnostic imaging was reviewed and statistically evaluated to detect circle of Willis anomalies, aneurysm size, and rupture. 204 patients with an unrelated diagnosis served as the control group. RESULTS: Variations of the A1 segment occurred significantly more frequently in the aneurysm group than in the control group. Mean aneurysm size in patients with grades I and III hypoplasia or aplasia was 6.58 mm whereas in patients with grade II hypoplasia it was 7.76 mm. CONCLUSIONS: We found that variations in the A1 segment of the ACAs are correlated with a higher prevalence of ACoA aneurysms compared with patients with a symmetric circle of Willis.

Intravascular perfusion of carbon black ink allows reliable visualization of cerebral vessels.

The anatomical structure of cerebral vessels is a key determinant for brain hemodynamics as well as the severity of injury following ischemic insults. The cerebral vasculature dynamically responds to various pathophysiological states and it exhibits considerable differences between strains and under conditions of genetic manipulations. Essentially, a reliable technique for intracranial vessel staining is essential in order to study the pathogenesis of ischemic stroke. Until recently, a set of different techniques has been employed to visualize the cerebral vasculature including injection of low viscosity resin, araldite F, gelatin mixed with various dyes (i.e. carmine red, India ink) or latex with or without carbon black. Perfusion of white latex compound through the ascending aorta has been first reported by Coyle and Jokelainen. Maeda et al. have modified the protocol by adding carbon black ink to the latex compound for improved contrast visualization of the vessels after saline perfusion of the brain. However, inefficient perfusion and inadequate filling of the vessels are frequently experienced due to high viscosity of the latex compound. Therefore, we have described a simple and cost-effective technique using a mixture of two commercially available carbon black inks (CB1 and CB2) to visualize the cerebral vasculature in a reproducible manner. We have shown that perfusion with CB1+CB2 in mice results in staining of significantly smaller cerebral vessels at a higher density in comparison to latex perfusion. Here, we describe our protocol to identify the anastomotic points between the anterior (ACA) and middle cerebral arteries (MCA) to study vessel variations in mice with different genetic backgrounds. Finally, we demonstrate the feasibility of our technique in a transient focal cerebral ischemia model in mice by combining CB1+CB2-mediated vessel staining with TTC staining in various degrees of ischemic injuries.

[Microsurgical anatomy importance of A1-anterior communicating artery complex]. / Importancia de la anatomía microquirúrgica del complejo A1-arteria comunicante anterior.

BACKGROUND: The anterior cerebral artery originates from the bifurcation of the internal carotid artery lateral to the optic chiasm, then joins with its contralateral counterpart via the anterior communicating artery. A1-anterior communicating artery complex is the most frequent anatomical variants and is the major site of aneurysms between 30 to 37%. OBJECTIVE: Know the anatomy microsurgical, variants anatomical and importance of complex precommunicating segment-artery anterior communicating in surgery neurological of the pathology vascular, mainly aneurysms, in Mexican population. METHODS: The study was performed in 30 brains injected. Microanatomy was studied (length and diameter) of A1-anterior communicating artery complex and its variants. RESULTS: 60 segments A1, the average length of left side was 11.35 mm and 11.84 mm was right. The average diameter of left was 1.67 mm and the right was 1.64 mm. The average number of perforators on the left side was 7.9 and the right side was 7.5. Anterior communicating artery was found in 29 brains of the optic chiasm, its course depended on the length of the A1 segment. The average length of the segment was 2.84 mm, the average diameter was 1.41 mm and the average number of perforators was 3.27. A1-anterior communicating artery complex variants were found in 18 (60%) and the presence of two blister-like aneurysms. CONCLUSION: It is necessary to understand the A1-anterior communicating artery complex microanatomy of its variants to have a three-dimensional vision during aneurysm surgery.

Antecedentes: la arteria cerebral anterior se origina de la bifurcación de la arteria carótida interna lateral al quiasma óptico, posteriormente se une con su homóloga contralateral mediante la arteria comunicante anterior. El complejo precomunicante(A1)-arteria comunicante anterior es el lugar más frecuente de variantes anatómicas y el sitio con mayor cantidad de aneurismas (30 a 37%). Objetivo: conocer la anatomía microquirúrgica, las variantes anatómicas y la importancia del complejo segmento precomunicante-arteria comunicante anterior en cirugía neurológica de la patología vascular, principalmente aneurismas, en población mexicana. Material y métodos: estudio prospectivo y descriptivo efectuado en el Departamento de Anatomía de la Facultad de Medicina (UNAM) en 30 encéfalos inyectados. Se estudió la anatomía microquirúrgica (longitud y calibre) del complejo segmento precomunicante-arteria comunicante anterior de la arteria cerebral anterior y sus variantes. Resultados: se encontraron 60 segmentos precomunicantes. La longitud promedio del lado izquierdo fue de 11.35 mm y del derecho de 11.84 mm. El calibre medio en el lado izquierdo fue de 1.67 mm y en el derecho de 1.64 mm. El número promedio de perforantes en el lado izquierdo fue de 7.9 y en el derecho de 7.5. La arteria comunicante anterior se encontró en 29 encéfalos sobre el quiasma óptico, su trayecto dependió de la longitud del segmento A1. La longitud media del segmento fue de 2.84 mm, el calibre fue de 1.41 mm y el número promedio de perforantes de 3.27. En 18 encéfalos (60%) se encontraron variantes del complejo A1-arteria comunicante anterior y dos aneurismas tipo blíster. Conclusión: es necesario entender la anatomía microquirúrgica del complejo segmento precomunicante-arteria comunicante anterior y conocer las variantes para tener una visión en tercera dimensión durante la cirugía de aneurismas.

Características biométricas de la arteria coroidea anterior en su segmento cisternal / Biometrical characteristics of anterior choroidal artery in its cisternal segment

Las implicancias clínicas que tienen los procesos oclusivos de la Arteria Coroidea Anterior (AChA), son de considerable importancia y nos han motivado para efectuar su análisis biométrico incorporando algunos otros parámetros. Para su ejecución, se utilizaron cerebros inyectados con látex coloreado de rojo fijados en solución de formol, provenientes del Servicio Médico Legal, Santiago.Para su observación, se usó lupa luminiscente 4 X y las mediciones efectuadas con Caliper Mitutoyo Digital. Esta arteria se originó de la Carótida Interna (ACI) en un 83,3 por ciento y en un 16,7 por ciento de la Arteria Comunicante Posterior (ACoP ). El calibre medio observado en su origen fue de 0,68 +/- 0,31 mm; en el tercio medio de 0,60 +/- 0,21 mm; en el punto de entrada en el plexo coroideo de 0,48 +/- 0,23 mm. La longitud media desde el origen de la AChA al plexo coroideo fue de 28,67 +/-6,33 mm; la distancia media desde su origen al de la ACoP fue de 6,97 +/- 4,89 mm. El número promedio de ramas perforantes registradas fue de 6. Nuestros resultados pueden ser una contribución a considerar en la clínica...

The clinical implications of occlusive processes in the anterior choroidal artery (AChA) are of considerable importance and have motivated us to perform a biometrical analysis of the afore mentioned artery including new biometric parameters (measurements). This study was perfomed on vascularized brains that were both fixed with for formalin solution and injected whith red tinted latex and brains that were not fixed with formalin solution, which were obtained from the Medical Legal Service, Santiago. They were observed using a luminescent 4 X magnifying glass and the measurements perfomed using a Mitutoyo Digital Caliper. This artery originated from the internal carotid artery (ICA) in 83.3 percent of the cases observed, and in 16.7 percent it originated from the posterior communicating artery ( PCoA). The mean caliber (diameter) of the artery was 0.68 +/- 0.31 mm at the point of origin; the middle third was 0.60 mm +/- 0.21 mm; at the point of entry into the choroidal plexus it was 0.48 mm +/- 0.23 mm. The mean length from its origin at the AChA to the choroidal plexus was 28.67 mm +/- 6.33 mm; the mean distance from its origin at the PCoAwas 6.97mm+/- 4.89 mm. The number of perforating branches of the AChA was 6. Our results can be considered a clinical contribution...

Microsurgical anatomy of the abducens nerve.

OBJECTIVE: To clarify the oriented classification, relationships, and variations of the abducens nerve and provide a detailed description of its microsurgical anatomic features. METHODS: A microsurgical anatomic dissection of the abducens nerve was performed in 100 specimens obtained from 50 adult cadaveric heads fixed in formalin and two adult cadaveric heads stained with hematoxylin and eosin for histological examination. Important neurovascular and structural relationships of the abducens nerve were observed. RESULTS: The abducens nerve was divided into five segments (cisternal, petroclival, internal carotid artery, fissural, and intraconal). It coursed in the petroclival venous confluence and there was a complex anatomic relationship. Two new types of abducens nerve variations were found. In one type, the duplicated nerve is split into two branches for a limited length in the cavernous sinus (CS). The other is a complex type, which has a complex course and pattern. This type of duplicated abducens nerve has a communicating branch in the cistern and numerous fasciculi in the CS. In addition, the two branches do not accompany each other for the entire course in the CS. CONCLUSION: The vulnerability of the abducens nerve results from diverse factors. The inferolateral trunk, which arises from the intracavernous segment of carotid artery (also called the artery of the inferior CS), is an important landmark for finding the abducens nerve and sympathetic nerve. Variations of the abducens nerve are not rare. Keeping variations of the nerve in mind is important during skull base operations and transvenous endovascular interventions. Understanding the relationship of the abducens nerve with adjacent structures will help us in preparing for safe surgery.