The Vertebrobasilar Trunk and Its Anatomical Variants: A Microsurgical Anatomical Study.

BACKGROUND: The trunk of the basilar artery has not been included in microanatomy studies. Anatomical variants of the perforant branches of the vertebrobasilar trunk and their relationship with neural structures are very important in surgical approaches. Surgical dissection for the treatment of vascular lesions requires a perfect knowledge of the microsurgical anatomy. METHODS: We conducted a descriptive analysis of 50 brains, which were fixed with formalin at 10% for 2 weeks, and the arterial system was injected with colored latex. After microsurgical dissection, it was divided into three segments: the lower portion went from the anterior spinal artery to the anteroinferior cerebellar artery, the middle segment was raised from the upper limit of the lower portion to the origin of the superior cerebellar artery, and the upper segment ranged from the previous portion until the origin of the posterior cerebral artery. RESULTS: The basilar artery had an average length of 30 mm. The average diameter at its junction with the vertebral arteries was 4.05 mm. The average middle segment was 3.4 mm in diameter and 15.2 mm in length. The diameter of the upper segment was 4.2 mm, and its average length was 3.6 mm. The average number of bulbar arteries was three, and their average diameter was 0. 66 mm. The number of caudal perforator arteries were five on average, with a diameter of 0.32 mm. We found three rare cases of anatomical variants in the vertebra-basilar junction. CONCLUSIONS: The basilar artery emits penetrating branches in its lower, middle, and upper portions. The origin of penetrating branches was single or divided after forming a trunk. However, we observed long branches from perforant arteries.

Latex vascular injection as method for enhanced neurosurgical training and skills.

Background: Tridimensional medical knowledge of human anatomy is a key step in the undergraduate and postgraduate medical education, especially in surgical fields. Training simulation before real surgical procedures is necessary to develop clinical competences and to minimize surgical complications. Methods: Latex injection of vascular system in brain and in head-neck segment is made after washing out of the vascular system and fixation of the specimen before and after latex injection. Results: Using this latex injection technique, the vascular system of 90% of brains and 80% of head-neck segments are well-perfused. Latex-injected vessels maintain real appearance compared to silicone, and more flexible vessels compared to resins. Besides, latex makes possible a better perfusion of small vessels. Conclusions: Latex vascular injection technique of the brain and head-neck segment is a simulation model for neurosurgical training based on real experiencing to improve surgical skills and surgical results.

Seno cavernoso: anatomía, histología y terminología.

BACKGROUND: Although the cavernous sinus (CS) has been studied since 1695, its anatomy and name are still under discussion. METHOD: Anatomy and histology of 40 CS from human cadavers were studied, included both from a newborn specimen. RESULTS: Two walls limit the CS, an inferior medial one composed only of the dura's outer layer and a superior lateral one consisting of both dura's layers. Sinusoidal veins pass through the lateral wall of the CS as a transition between venous tributaries and the CS. An endothelial layer covers the inner surface of the CS and the outer surface of the internal carotid artery. The space within the CS shows trabeculae, which are rarer in adults compared to the newborn. The loss of trabeculae in the CS may be a natural process along with life. CONCLUSIONS: In conclusion, the CS is a real sinus, and the term "cavernous sinus" is appropriately applied.

ANTECEDENTES: Si bien el seno cavernoso (SC) ha sido estudiado desde 1695, su anatomía y nombre aún están bajo discusión. MÉTODOS: Se estudiaron la anatomía y la histología de 40 SC de cadáveres humanos, incluyendo los dos de un recién nacido. RESULTADOS: El SC está limitado por dos paredes, una inferomedial compuesta solo por la capa más externa de la duramadre y otra superolateral compuesta por ambas capas de la duramadre. Hay venas sinusoidales que atraviesan la pared lateral del SC formando una transición entre venas tributarias y el SC. Una capa endotelial recubre la superficie interna del SC y la superficie externa de la arteria carótida interna. El espacio dentro del SC presenta trabéculas, las cuales son escasas en el adulto en comparación con el recién nacido. La pérdida de trabéculas en el SC puede ser un proceso natural a lo largo de la vida. CONCLUSIONES: En conclusión, el SC es un verdadero seno, por lo que el término «seno cavernoso¼ se aplica de forma correcta.

Neuroanatomical basis of Wallenberg syndrome.

Wallenberg syndrome, or lateral medullar syndrome, is the clinical presentation of the infarct in the territory of posterior inferior cerebellar artery. Its signs and symptoms include vertigo, nystagmus, diplopia, ipsilateral Horner syndrome, facial ruddiness and dry skin, dysphonia, dysphagia, dysarthria, ipsilateral loss of gag reflex, ipsilateral ataxia, ipsilateral impaired taste, ipsilateral facial pain and paresthesia, decreased ipsilateral blink reflex, contralateral hypoalgesia and thermoanaesthesia in the trunk and limbs; and ipsilateral facial hypoalgesia and thermoanaesthesia. Neuroanatomical knowledge is essential to its comprehension, study and diagnosis, because the classic neurological manifestations are easy to explain and understand if function and localization of affected anatomical structures are known as if the posterior cerebral circulation is.

El síndrome de Wallenberg, o síndrome bulbar lateral, es la manifestación clínica del infarto en el territorio de irrigación de la arteria cerebelosa posteroinferior. Su presentación incluye vértigo, nistagmo, diplopía, síndrome de Horner, rubicundez y anhidrosis facial homolateral, disfonía, disfagia, disartria, pérdida homolateral del reflejo nauseoso, ataxia homolateral, disgeusia homolateral, dolor y parestesia faciales homolaterales, pérdida o disminución homolateral del reflejo corneal, hipoalgesia y termoanestesia de tronco y extremidades contralaterales, hipoalgesia y termoanestesia facial homolateral. El conocimiento neuroanatómico es imprescindible para su comprensión, estudio y diagnóstico, ya que sus manifestaciones neurológicas clásicas son fácilmente explicables y entendibles si se conocen la función y la localización de las estructuras anatómicas afectadas, así como la irrigación cerebral posterior.

[Effectiveness of Trauma Evaluation and Management course for Mexican senior medical students: When to implement it?]. / Efectividad del curso Evaluación y Manejo del Trauma en estudiantes de Medicina mexicanos: ¿cuándo implementar?

BACKGROUND: Trauma Evaluation and Management course was designed to develop trauma cognitive skills in senior medical students. Its effectiveness has been demonstrated in many regions, except in Latin America, where it has been poorly studied. The objective was to determine the Trauma Evaluation and Management course effectiveness, and whether greater effectiveness is achieved in basic- or clinic-cycle students, as well as student perception. MATERIAL Y METHODS: Descriptive, observational, longitudinal and prospective study. Two tests were performed, pre- and post-course; the manual was read by the students prior to both tests. Students were divided into 2 groups: group A (consisting of 71 basic-cycle medical students) and group B (consisting of 44 clinical-cycle medical students). RESULTS: Group A achieved a 2.45 increase (p<0.01) in the post-course evaluation compared with pre-course test. Group B increased the mean score by 2.25 (p>0.05) from pre- to post-course tests. There was a significant difference between groups in both evaluations (pre-course test p<0.01 and post-course test p>0.05), with no difference in improvement (p>0.05). Using a questionnaire, 92.17% of the students totally agreed that the course improved their trauma knowledge, 76.52% that it increased their trauma clinical skills, with 94.78% being totally satisfied with the course, and 86.09% totally agreed that Trauma Evaluation and Management course should be in Medicine curriculum. CONCLUSIONS: Trauma Evaluation and Management course improves trauma cognitive skills, and undergraduate medical students in Mexico broadly accept it.

[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.

[Association of three anatomical variants of the anterior cerebral circulation]. / Asociación de tres variantes anatómicas de circulación cerebral anterior.

BACKGROUND: As part of a study of the microsurgical anatomy of the pericallosal artery, we describe one brain with three unusual anatomical variants. METHODS: From the autopsy of a 45 year-old female, we extracted the brain and all the arterial blood vessels were washed off with saline solution to be injected afterwards with red latex. The brain was then immersed in 10% formalin for two months. Finally, we dissected and measured the internal carotid artery segments, using a digital Vernier caliper under a Carl Zeiss OPMI surgical microscope with magnification of 6x up to 40x. RESULTS: The brain's weight was 1250 grams and three rare anatomical variants were found: 1) right accessory middle cerebral artery (ACMA-d), 2) right bihemispheric anterior cerebral artery (ACABihem-d), 3) median artery of the corpus callosum (AMCC). CONCLUSION: The association of the anatomical variations described previously is inconstant; furthermore, their appearance in a single case is rare.

Microsurgical anatomy of the extracerebral segment of recurrent artery of Heubner in the Mexican population.

BACKGROUND: The recurrent artery of Heubner (RAH) is originated commonly from the anterior cerebral artery. Its extracerebral segment is directed toward the anterior perforate substance where it penetrates the cortex. METHODS: The RAH was dissected from 15 human brains from Mexican population, and the presence, length, branches, course and either RHAs or anterior communicating artery complex variants were reported. RESULTS: The RAH was found in 93% of the hemispheres and duplicated in 39% of the hemispheres. The RAH was duplicated in at least a hemisphere in 46.6% of the brains; 40% of the brains had a RAH in every hemisphere. It was duplicated in every hemisphere in 20%. A single artery at a hemisphere was found in 26.6% and double at the other hemisphere. With a length between 13.6 and 36.7 mm (mean: 24.2 mm) and giving rise to 1-9 branches (mean: 3.9 branches), the RAH originated from the juxtacommunicating segment in 44% of the cases, from A2 in 41%, from A1 in 5% and as a branch of the frontopolar artery in 10%. It had an oblique course in 38%, an L in 31%, sinuous in 18% and an inverted L in 13%. In 53.3% of the brains, some variant of the anterior communicating artery complex was found. CONCLUSIONS: Because of the common anatomy of the RAH and its variants, we must consider the probability of finding it duplicated; therefore, it is necessary to make minute dissections of the region to locate or to secure the absence of the RAH.