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.

White Matter Topographic Anatomy Applied to Temporal Lobe Surgery.

BACKGROUND: The temporal lobe is an important and complex anatomic region of the brain. Accurate knowledge of anatomic relationships becomes extremely relevant when deciding surgical strategy, such as epilepsy or oncologic surgery, involving this lobe. To our knowledge, there is no strong literature highlighting the relationship between white matter tracts and craniometric landmarks applied to temporal lobe surgery. We aim to describe the topographic relationship between the craniometric points and white matter tracts of the temporal lobe through dissection of cadaveric specimens and describe the potential preoperative usefulness of diffusion tensor imaging in relation to the anatomic features found during the dissections. METHODS: Fifteen formalin-fixed whole cadaveric heads were dissected by the Klingler technique in a stepwise manner across the temporal and sphenoid bone windows. The white matter pathways were identified in their different planes and their position was described in relation to craniometric landmarks. Diffusion tensor studies were performed in 2 healthy volunteers to analyze the temporal fasciculi in vivo. RESULTS: We identified the topographic relationships between craniometric points and relevant association tracts that lie within the cranial corridors (superior and inferior frontal, parietal, occipital, sphenoidal, and temporal). Important landmarks were defined in correspondence to these different fasciculi. CONCLUSIONS: Through this kind of microsurgical anatomic study, a better understanding of the different anatomic layers of the temporal region might be achieved. This factor is essential in planning adequate surgery and strategies to operate in the temporal lobe, improving surgical results and minimizing functional deficits.