Navegando por la fisura silviana: anatomía microquirúrgica, neuroimágenes y técnica quirúrgica / Navigating the sylvian fissure: microsurgical anatomy, neuroimaging, and surgical technique

Objetivo: Describir la anatomía quirúrgica de la fisura silviana (FS) a través de disecciones cadavéricas y neuroimágenes; desarrollar su aplicación microquirúrgica. Materiales y métodos: Se estudiaron 10 hemisferios cadavéricos humanos fijados y un cráneo humano en seco, a través de la disección de fibras blancas y de la anatomía arterial y neural, utilizando un microscopio quirúrgico. Las arterias cerebrales fueron inyectadas con silicona coloreada. La anatomía quirúrgica fue correlacionada con la anatomía neuroimagenológica. Finalmente, se recolectó la experiencia microquirúrgica adquirida y, a su vez, la anatomía del Complejo Silviano, fue revisada. Resultados: La FS se extiende desde la cara basal a la lateral del cerebro. Cada superficie tiene una parte superficial (tronco silviano y sus ramos), intermedia (compartimientos anterior y opercular lateral) y profunda (compartimiento esfenoidal, hendidura insular anterior y lateral y la región retroinsular). En 7 de los 10 hemisferios, el surco central no se intersectó con la FS en la superficie lateral del cerebro. En el 80% de los hemisferios, la principal bifurcación de la arteria cerebral media se localizó en o proximal al limen insular. Debajo de la pars triangularis se localiza el punto más ancho de la superficie lateral de la FS. Los autores comienzan la disección de la misma en o proximalmente a este punto. Conclusiones: El conocimiento anatómico profundo y su aplicación a las neuroimágenes, son herramientas esenciales para el planeamiento prequirúrgico y son requisitos mandatorios para operar con seguridad a través y alrededor de la FS

Objective: The aim of this study is to describe the microsurgical anatomy of the sylvian fissure, through cadaveric dissections and neuroimaging and to elucidate its clinical application for microsurgery. Methods: One human skull and ten cadaveric human hemispheres were studied through white matter fiber dissections and arterial and neural anatomy of the sylvian fissure and insular dissections under the microscope. The cerebral arteries were perfused with colored latex. The surgical anatomy was correlated with neuroimaging anatomy. Finally, the microsurgical experienced gained applying this anatomical knowledge was gathered, and the literature about the anatomy of the sylvian complex was revised, as well. Results: The Sylvian fissure extends from the basal to the lateral surface of the brain. Each surface has a superficial (sylvian stem and its rami), intermediate (anterior and lateral opercular compartments) and deep parts (sphenoidal compartment, anterior and lateral insular clefts and retroinsular region). In 7 out of 10 hemispheres, the central sulcus did not intersect with the sylvian fissure on the lateral surface of the brain. In 80% of the hemispheres, the middle cerebral artery main bifurcation was localized at or proximal to the limen insulae. Beneath the pars triangularis, the widest point of the lateral surface of the sylvian fissure is located. The authors start dissecting the sylvian fissure at this point. Conclusion: The thorough anatomical knowledge with its clinical application in modern neuroimaging are essential tools for preoperative planning and are mandatory requisites to safely operate through and around the sylvian fissure anatomical complex.

El lóbulo de la ínsula: Parte 2 - Anatomía microquirúrgica y correlación clínico-quirúrgica / The lobe of the insula: Part 2 - Microsurgical anatomy and clinical-surgical correlation

Introducción: El conocimiento profundo de la anatomía microquirúrgica del lóbulo de la ínsula es crucial para operar pacientes con tumores en esta región. Objetivo: El objetivo de la segunda parte de este estudio es correlacionar la anatomía microquirúrgica con casos ilustrativos retirados de nuestra casuística de 35 pacientes en los cuales fueron realizados 44 cirugías de tumores en relación con el lóbulo de la ínsula. Material y Métodos: A lo largo de marzo de 2007 y agosto de 2014, 44 microcirugías fueron realizadas en 35 pacientes portadores de tumores insulares y los hallazgos de las cirugías y mapeo cerebral se correlacionaron con la anatomía microquirúrgica. Resultados: De una serie de 44 pacientes con tumores de la ínsula, la mayoría de los casos eran gliomas de bajo grado de malignidad (29 casos). El inicio de los síntomas en 34 pacientes fue epilepsia, siendo esta refractaria al tratamiento medicamentoso en 12 casos. El grado de resección fue subtotal o total en la mayoría de los casos de la serie. La mejoría en la calidad de vida (epilepsia, etc.) estuvo presente en más de la mitad de los pacientes. El déficit neurológico permanente estuvo presente en tres pacientes. Conclusión: En los tumores insulares, es tan importante el conocimiento profundo de la anatomía, como el saber utilizar e interpretar en tiempo real las observaciones de la monitorización neurofisiológica intraoperatoria.

Introduction: The deep knowledge of the microsurgical anatomy of the insular lobe is crucial to operate patients with tumors in this region. Objectives: Our purpose in this second part is to correlate insular surgical anatomy with illustrative cases from 4 surgeries performed on 35 patients with insular tumors. Materials and Methods: From March 2007 to August 2014, 44 microsurgeries were performed on 35 patients with insular glioma tumors. Of these, 29 cases were low-grade gliomas. Seizures were the first symptom in most cases. Total, or near total tumor resection was achieved in most of the patients. Improvement in quality of life was achieved in more than half of the patients after surgery. Moderate and permanent neurological deficits were present in 3 patients. Results: The majority of cases were low grade malignancy gliomas (29 cases). The onset of symptoms in 34 patients was epilepsy, being refractory to drug treatment in 12 cases. The degree of resection was subtotal or total in most cases of this series. The improvement in the quality of life (epilepsy, etc.) was present in more than half of the patients. Permanent neurological deficit was present in three patients. Conclusion: For insular tumors, microsurgical anatomy knowledge is as important as cortical and subcortical mapping

Parte I: Anatomía microquirúrgica tridimensional de la ínsula / Part I: Three-dimensional microsurgical anatomy of the insula

Introducción: El lóbulo de la ínsula, o ínsula, se encuentra oculto en la superficie lateral del cerebro. La ínsula está localizada profundamente en el surco lateral o cisura silviana, recubierta por los opérculos frontal, parietal y temporal. Objetivo: Estudiar la compleja anatomía del lóbulo de la ínsula, una de las regiones de mayor complejidad quirúrgica del cerebro humano, y su correlación anatómica con casos quirúrgicos. Material y Métodos: En la primera parte de este estudio presentamos los resultados de nuestras disecciones microquirúrgicas en fotografías 2 D y 3D; en la segunda parte de nuestro trabajo, la correlación anatómica con una serie de 44 cirugías en pacientes con tumores de la ínsula, principalmente gliomas, operados entre 2007 y 2014. Resultados: Extenso conjunto de fibras subcorticales, incluyendo el fascículo uncinado, fronto-occipital inferior y el fascículo arcuato, conectan la ínsula a las regiones vecinas. Varias estructuras anatómicas responsables por déficits neurológicos severos están íntimamente relacionadas con la cirugía de la ínsula, tales como lesiones de la arteria cerebral media, cápsula interna, áreas del lenguaje en el hemisferio dominante y arterias lenticuloestriadas. Conclusión: El entrenamiento en laboratorio de neuroanatomía, estudio de material impreso en 3D, el conocimiento sobre neurofisiología intra-operatoria y el uso de armamento neuroquirúrgico moderno son factores que influencian en los resultados quirúrgicos

Introduction: The insular lobe, or insula, is the cerebral lobe sitting deep in the sylvian fissure and hidden by the lateral surface of the brain. It is covered by the frontal, parietal and temporal operculum. Objectives: To study the anatomy of the insular lobe, one of the most complex parts of the human brain, and to correlate this anatomy with intraoperative findings. Materials and Methods: In the first part of this article we show the results of our dissections, documented in 2D and 3D, and focus on microsurgical anatomy. In the second part we correlate the anatomical structures with intraoperative findings from 44 insular tumor surgeries, mainly gliomas, of patients operated on from 2007 to 2014. Results: Huge bundles of subcortical fibers, like uncinate, inferior fronto-occipital and arcuate fascicles, connect the insula to the neighboring structures. Several anatomical structures related to neurological disabilities are closely related to insular surgery, like the middle cerebral artery, internal capsule, lenticulostriate arteries and cortical and subcortical language circuits. Conclusions: Microsurgical laboratory training, 3D documentation, knowledge of brain mapping and modern neurosurgical armamentarium are important factors in achieving good results with insular glioma tumors.

An anatomic study of superficial temporal artery to anterior cerebral artery bypass using ipsilateral parietal branch of superficial temporal artery as graft / 中华显微外科杂志

Objective Revascularization of the distal segment of the anterior cerebral artery (ACA) using extracranial donors requires long interposition grafts.A novel bypass procedure which uses the two main branches of the superficial temporal artery (STA) to reach the A3 segment of the anterior cerebral artery with a single skin incision was designed.Methods Ten cadaveric specimens were dissected through a single skin incision to harvest the frontal and parietal branches of the STA from June,2017 to September,2017.An anterior interhemispheric approach provided access to the middle internal frontal artery (MIFA).The parietal STA was used as an interposition graft between the frontal STA and MIFA.Lengths and calibers of the distal branches of STA and MIFA were measured at the anastomotic sites.All data was statistical analysis by t-test.Results The average caliber of MIFA was (1.4±0.2) mm,which matched the caliber of both frontal and parietal branches of STA.The mean distance for an end-to-side bypass from STA to MIFA was (144.5±7.4) mm and the average harvested donor-graft complex length was (203.1±27.9) mm.This bypass construct provided around 140％ donor graft length.Conclusion Using the parietal branch of the STA as an interposition graft enabled a successful tension-free STA-MIFA bypass.The advantages of this technique over existing approaches include sufficient graft length,caliber match and relative technical ease.

Microsurgical Anatomy of Supraclinoid ICA in North West Indian Population: A Cadaveric Study.

Background: To study the microsurgical anatomy of supraclinoid ICA, the size and number of perforators, any anomalies in normal anatomy of ICA, its branches and surrounding structures in North West Indian population. Materials and Methods: Twenty cadaveric brain dissections were performed under operating microscope (Carl ZeissNC31). Sylvian fissure was meticulously dissected from distal to proximal. Anterior clinoid process (ACP) was drilled intradurally using M-80 pneumatic drill. Vessels, their branches and perforators were dissected with measurement of their length, diameter and number. Supraclinoid ICA was dissected till its bifurcation into anterior and middle cerebral arteries. The length of falciform ligament was also measured. Results: The length of ophthalmic segment was largest varying from 5.5 to 13.0 mm (average 9.75mm).The communicating segment was the shortest varying from 1.5 to 6.0 mm (average 3.2mm). The number of perforating arteries excluding the OphA, PComA and AChA arising from C4 varied from 3-10(average 6). The maximum perforators were from Cho Seg and least from Com Seg. Conclusion: The overall anatomical details of supraclinoid ICA in North West Indian population were comparable to existing literature.

Clinical anatomy study of the far lateral suboccipital approach / 局解手术学杂志

Objective To study the microsurgical anatomy marks and parameters for thefar lateral suboccipital approach and to protect the vital structure in operations. Methods Through the far lateral suboccipital approach, 10 adult cadveric heads were anatomized. Under the microscopy, the involving muscles, bony structures, vessels and nerves were observed and measured anatomically. Results The distance from asteria to asteria was (21. 68 ± 1. 88) mm on the left and (22. 34 ± 2. 62) mm on the right. The distance from anterior asteria to mas-toidale was (38. 56 ± 3. 48) mm on the left and (39. 14 ± 2. 24) mm on the right. The distance from asteria to root of zygoma was (55. 72 ± 3. 64) mm on the left and (56. 16 ± 2. 72) mm on the right. Conclusion The suboccipital triangle and C2 nerve were the significant marks which can identify the vertebral artery. The bone anatomic landmarks in the far lateral suboccipital approach included anterior asteria, aste-ria, mastoidale and root of zygoma. These marks contributed the successful implementation of the far lateral suboccipital approach surgery.

Cortical projection of the inferior choroidal point as a reliable landmark to place the corticectomy and reach the temporal horn through a middle temporal gyrus approach / Projeção cortical do ponto coroideo inferior como uma referência anatômica confiável para a realização da corticectomia e abordagem do corno temporal através do giro temporal médio.

Objective To establish preoperatively the localization of the cortical projection of the inferior choroidal point (ICP) and use it as a reliable landmark when approaching the temporal horn through a middle temporal gyrus access. To review relevant anatomical features regarding selective amigdalohippocampectomy (AH) for treatment of mesial temporal lobe epilepsy (MTLE). Method The cortical projection of the inferior choroidal point was used in more than 300 surgeries by one authors as a reliable landmark to reach the temporal horn. In the laboratory, forty cerebral hemispheres were examined. Conclusion The cortical projection of the ICP is a reliable landmark for reaching the temporal horn. .

Objetivo Estabelecer a projeção cortical do ponto coiroideo inferior e usá-la como referência para realizar a corticectomia e a abordagem do corno temporal do ventrículo lateral em cirurgias para o tratamento da epilepsia temporal mesial. Método A projeção cortical do ponto coroideo inferior foi utilizada por um dos autores seniors em mais de 300 casos de epilepsia temporal mesial para atingir o corno temporal do ventrículo lateral. Conclusão A projeção cortical do ponto coroideo inferior foi útil e confiável na abordagem do corno temporal do ventrículo lateral e ela está geralmente localizada na margem inferior do giro temporal médio, em média, a 4,52 cm posterior ao polo temporal. .

Anatomic study of the optical radiation and its relationship in the temporal lobe: definition of a secure approach for amigdalohipocampectomy in epilepsy surgery / Estudio anatómico de la radiación óptica y su relación en el lóbulo temporal: definición de un abordaje seguro para amigdalohipocampectomía en cirugía de la epilepsia

Introducción/Objetivos: El lóbulo temporal anterior tiene importantes estructuras subcorticales, especialmente fibras blancas que llevan la información visual. La comprensión de esta región anatómica, importantes para la práctica microquirúrgica, se basa en técnicas de disección de fibras. Ellos proporcionan perspectiva tridimensional de esta región y añaden un enfoque quirúrgico exitoso para el tratamiento de las lesiones temporales mesiales. El propósito de este trabajo es el estudio de la anatomía de la pared lateral del ventrículo lateral con el fin de determinar una zona libre de la radiación óptica. Métodos: Se diseccionaron diez hemisferios cerebrales, preparados de acuerdo con técnicas de Klingler. Se utilizan espátulas de madera con puntas de diferentes tamaños. La radiación óptica fue delimitada y las medidas se tomaron a partir de esta estructura para el polo temporal, que se utiliza como punto de referencia. Resultados: Abordajes para el cuerno temporal superior a 27 mm más allá del polo temporal pueden cruzar asa de Meyer y determinar un perjuicio a la radiación óptica con los consiguientes déficits en los campos visuales. Conclusión: La determinación de la zona de libre de fibras de radiación óptica es factible. En este trabajo se podría inferir que el área libre de la radiación óptica se encuentra en la región anterioinferior del lóbulo temporal a una distancia de hasta 2,7 centímetros desde el polo temporal y permite el acceso a el hipocampo y la amígdala durante la cirugía de la epilepsia. Resecciones más grandes que estas medidas permiten aclarar de una lesión a la radiación óptica con los consiguientes déficits en los campos visuales.

Introduction/Objective: The anterior temporal lobe has important subcortical structures, especially white fibers that lead visual information. Understanding this anatomical region, important for microsurgical practice, is based on fibers dissection techniques. They provide three-dimensional perspective for this region and add a successful surgical approach for the treatment of mesial temporal lesions. The purpose of this paper is to study the anatomy of the lateral wall of the lateral ventricle in order to determine a free area of the optical radiation. Methods: Ten cerebral hemispheres were dissected, prepared according to Klingler´s techniques. Wooden spatulas with tips of various sizes were used. The optical radiation was delimited and measures were taken from this structure to the temporal pole, used as a reference point. Results: Approaches to the temporal horn larger than 27 mm beyond the temporal pole can cross Meyer´s loop and determine injury to the optical radiation with consequent postoperatively deficits in visual fields. Conclusion: The determination of free area of optical radiation fibers is feasible. In this work we could infer that free area of optical radiation is located in the anterioinferior region of the temporal lobe at a distance of up to 2.7 centimeters from the temporal pole and allows access to the hippocampus and amygdala during epilepsy surgery. Larger resections than these measures can possibly determine injury to the optical radiation with consequent deficits in visual fields.

The microsurgical anatomy of the modified presigmoid transpartial bony labyrinth approach / 中华显微外科杂志

Objective To investigate the surgical techniques of the modified presigmoid trans-partial bony labyrinth approach and the advantages in exposure of the petroclival region and in treat the lesion of this area.Methods By simulate the modified presigmoid trans-partial bony labyrinth approach in 15 adult cadaveric heads with the aid of an operating microscope and record important structures in the petroclival region.Results The petroclival region,the posterior cavernous sinus,Meckel cave,the vertebral-basilar artery,the anterior inferior cerebellar artery,the superior cerebellar artery,ipsilateral Ⅲ-Ⅹ cranial nerve nere fully exposured and contralateral Ⅵ cranial nerve were fully exposured.The range of presigmoid exposure was (19.41 ± 1.58)mm,the exposurein of inferior temporal was (14.18 ± 1.88) nun,the maximum exposure angle of slope center depression was (60.54 ± 6.93) °,the depth of operation was (55.87 ± 4.34) mm.Conclusion The advantages of the modified presigmoid trans-partial bony labyrinth approach can earn enough exposures of deep part of petroclival region and posterior part of cavernous sinus,improved petroclival exposure,multiple axes of visualization,preservation of hearing and facial nerve function,and early devascularization of the tumor.

The Microsurgical Anatomical Study of transcerebellomedullary fissure approach / 中国神经精神疾病杂志

Objective To study transcerebellomedullary fissure approach to the fourth ventricle and the lateral brainstem without splitting vermis and depict its adjacent structure, and provide clinicians with anatomical information.Methods Five cadaveric heads fixed with formaldehyde and perfused with color latex in their arteries and veins were dissected with microsurgical anatomical skills. The composition of cerebellomedullary fissure and the distribution of the tela choroida, the inferior medullary velum and the posterior inferior cerebellar artery, and study anatomic base of this approach.Results Cerebellomedullary fissure is a natural anatomical gap which is located between the cerebellar tonsil, biventral lobule and medulla oblongata. The tela choroida and inferior medullary velum do not contain nerve tissue, and thus can be dissected to expose the fourth ventricle. The tonsil- medulla segment and telovelotonsillar segment of the posterior inferior cerebellar artery are the most important blood vessels of the cerebellomedullary fissure approach.Conclusions The transcerebellomedullary fissure approach can reach the fourth ventricle and dorsal brain stem through normal anatomic spaces without splitting the vermis, thus reducing the post-operative complications.

Microsurgical Anatomy of the Basilar Artery: Surgical Approaches to the Basilar Trunk and Vertebrobasilar Junction Aneurysms / 대한뇌혈관학회지

The success of treating basilar aneurysms lies in the preservation of all perforating arteries and best selection of the surgical approaches. The purpose of this study was to define the microsurgical anatomy of the basilar artery and surgical approaches to the basilar artery. The microsurgical anatomy of the basilar artery and its branches were evaluated in adult cadaveric brains using 3x to 20x magnification. The branches of the basilar artery can be divided into three main groups: the cerebellar, lateral pontine, and perforating arteries. The lateral pontine arteries arise from the basilar trunk and course laterally to the brachium pontis. The perforating arteries originated from the basilar trunk and penetrating near the midline of the pons on its basal surface. The basilar trunk was approached via subtemporal-transtentorial, anterior transpetrosal, posterior transpetrosal and transchondylar routes. Selection of approach for basilar aneurysms was discussed.

Neurovascular Morphometric Aspect in the Region of Cranio-Cervical Junction

OBJECTIVE: During the trans-condylar or trans-jugular approach for the lesion of cranio-cervical junction(CCJ), its necessary to identify the accurate locations of vertebral artery(VA), internal jugular vein(IJV) and its related lower cranial nerves. These neurovascular structures can also be damaged during the operation for vascular tumor or traumatic aneurysm around extra-jugular foramen, because of their changed locations. To reduce the neurovascular injury at the operation for CCJ, morphometric relationship of its surrounding neurovascular structures based on the tip of the transverse process of atlas(C1 TP), were studied. MATERIALS AND METHODS: Using 10 adult formalin fixed cadavers, tip of mastoid process(MT) and TPs of atlas and axis were exposed bilaterally after removal of occipital and posterior neck muscles. Using standard caliper, the distances were measured from the C1 TP to the following structures: 1) exit point of VA from C1 transverse foramen, 2) branching point of muscular artery from VA, 3) entry point of VA into posterior atlanto-occipital membrane(AOM), 4) branching point of C-1 nerve. In addition, the distances were measured from the mid-portion of the posterior arch of atlas to the entry point of the VA into AOM and to the exit point of the VA from C1 transverse foramen. After removal of the ventrolateral neck muscles, neurovascular structures were exposed in the extra-jugular foraminal region. Distances were then measured from the C1 TP to the following structures: 1) just extra-jugular foraminal IJV and lower cranial nerves, 2) MT and branching point of facial nerve in parotid gland. In addition, distance between MT and branching point of facial nerve was measured. RESULTS: The VA was located at the mean distance of 12mm(range, 10.5-14mm) from the C1 transverse foramen and entered into the AOM at the mean distance of 24mm(range, 22.8-24.4mm) from the C1 TP. The mean distance from the mid portion of the C1 posterior arch was 20.6mm(range, 19.1-22.3mm) to the entry point of the VA into AOM and 38.4mm(range, 34-42.4mm) to the exit point of the VA from C1 transverse foramen. Muscular artery branched away from the posterior aspect of the transverse portion of VA below the occipital condyle at the mean distance of 22.3mm(range, 15.3-27.5mm) from the C1 TP. The C-1 nerve was identified in all specimens and ran downward through the ventroinferior surface of the transverse segment of VA and branched at the mean distance of 20mm(range, 17.7-20.3mm) from the C1 TP. The IJV was located at the mean distance of 6.7mm(range, 1-13.4mm) ventromedially from the lateral surface of the C1 TP. The XI cranial nerve ran downward on the lateral surface of the IJV at the mean distance of 5mm(range, 3-7.5mm) from the C1 TP. Both IX and X cranial nerves were located in the soft tissue between the medial aspect of the internal carotid artery(ICA) and the medial aspect of the IJV at the mean distance of 15.3mm(range, 13-24mm) and 13.7mm(range, 11-15.4mm) from the C1 TP, respectively. The IX cranial nerve ran downward ventroinferiorly crossing the lateral aspect of the ICA. The X cranial nerve ran downward posteroinferior to the IX cranial nerve and descended posterior to the ICA. The XII cranial nerve was located between the posteroinferior aspect of the IX cranial nerve and the posterior aspect of the ICA at the mean distance of 13.3mm(range, 9-15mm) ventromedially from the C1 TP. The distance between MT and C1 TP was 17.4mm(range, 12.5-23.9mm). The VII cranial nerve branched at the mean distance of 10.2mm(range, 6.8-15.3mm) ventromedially from the MT and at the mean distance of 17.3mm(range, 13-21mm) anterosuperiorly from the C1 TP. CONCLUSION: This study facilitates an understanding of the microsurgical anatomy of CCJ and may help to reduce the neurovascular injury at the surgery around CCJ.

Microsurgical Anatomy of the Basilar Artery and Posterior Cerebral Artery / 대한뇌혈관학회지

The microsurgical anatomy of the basilar artery and posterior cerebral artery(PCA) was reviewed. Segments, major branches, perforating branches, anomalies of the basilar artery and PCA were summarized.

Microsurgical Anatomy of Intracranial Venous System / 대한뇌혈관학회지

OBJECTS: Although plenty of articles about microsurgical anatomy of the cerebral arteries exist in literatures, there is a few articles which studied the microsurgical anatomy of the cerebral venous system. To get the more accurate knowledge about microsurgical anatomy of the cerebral venous system related to the commonly used surgical approach route for cerebovascular lesions, this study is performed. MATERIAL AND METHODS: The author reviewed several articles which described about the anatomy of cerebral venous system, and selected some articles which studied the microsurgical anatomy of cerebral veins related to the area of the surgical approach routes for cerebrovascular lesions. General venous anatomy of lateral surface of cerebral hemisphere and the venous system related to the surgical approach route are described. RESULTS: The superficial cortical veins of lateral surface of cerebral hemisphere are divided into an ascending group, which drain into superior sagittal sinus, and a descending group, which drain into superficial sylvian veins or transverse sinus. Three anastomotic veins, such as the vein of Labbe, Trolard and the superficial sylvian veins, connect between superior sagittal sinus, veins along the sylvian fissure and transverse sinus. The anatomical knowledge of the sylvian and frontal basal veins, venous sinus around the superior sagittal sinus and medial frontal veins, and temporal basal veins are required in pterional, interhemispheric, and subtemporal approach respectively. CONCLUSION: The author concludes that the advancement of anatomical knowledge about cerebral venous system will contribute the improvement of outcome of surgically treated patients with cerebrovascular disease.

Microsurgical Anatomy of the Anterior Cerebral Artery / 대한뇌혈관학회지

The microsurgical anatomical characteristics of the anterior cerebral artery(ACA) are described. Inequality of horizontal segment of ACA has been reported. The majority of anterior communicating artery (ACoA) aneurysms occur in association with dominance of one A1 and hypoplasia of the other. ACoA has variation such as dimple, fenestration duplication, string, median artery of the corpus callosum and azygos anterior cerebral artery. ACoA gives rise to the perforating branches which feed subcallosal, hypothalamic area and optic chiasm. The recurrent artery of Heubner arises at A1-A2 junction, proximal A2 or distal A1. The distal ACA gives origin to many cortical branches, but there is the large variety of their origin. The aneurysm arising from A1 could be clipped through the pterional route, and those of distal ACA throuph the interhemispheric approach. ACo aneurysm could be approached through pterional or interhemspheric route. Essential points in ACo aneurysm surgery through any approach are to confirm H complex and to clip aneurysmal neck precisely without compromising feeding arteries or perforating branches.

Microsurgical Anatomy of the Anterior Cerebral Artery / 대한뇌혈관학회지

The microsurgical anatomical characteristics of the anterior cerebral artery(ACA) are described. Inequality of horizontal segment of ACA has been reported. The majority of anterior communicating artery (ACoA) aneurysms occur in association with dominance of one A1 and hypoplasia of the other. ACoA has variation such as dimple, fenestration duplication, string, median artery of the corpus callosum and azygos anterior cerebral artery. ACoA gives rise to the perforating branches which feed subcallosal, hypothalamic area and optic chiasm. The recurrent artery of Heubner arises at A1-A2 junction, proximal A2 or distal A1. The distal ACA gives origin to many cortical branches, but there is the large variety of their origin. The aneurysm arising from A1 could be clipped through the pterional route, and those of distal ACA throuph the interhemispheric approach. ACo aneurysm could be approached through pterional or interhemspheric route. Essential points in ACo aneurysm surgery through any approach are to confirm H complex and to clip aneurysmal neck precisely without compromising feeding arteries or perforating branches.

Microsurgical anatomy of the presigmoid translabyrinthine keyhole approach / 中华显微外科杂志

Objective To design a new presigmoid translabyrinthine keyhole approach assisted by Stryker neuro-navigation system according to the keyhole idea,and observe microscopic anatomy structures, which could be.regarded as the bases of this approach in clinical application.Methods Navigation data were established on 8 cadaveric heads fixed by formalin and perfused intracranial vessels with colored silicone. A 7-cm postauricular C-shaped skin incision as we reported was performed.After elevating the skin flap and musculofascial flap,a 3.5 cm?3.0 cm bone window was made.On skeletonizing the sigmoid sinus,bony lab- yrinth and the canal for facial nerve,the presigmoid retrolabyrinthine,partial labyrinthectomy with petrous api- cectomy,translabyrinthine keyhole approaches were simulated in turn.The length of important structures ex- posed and the angle of vision were measured step by step, and the anatomic structures were observed.Re- suits The approach-correlated bone could precisely be drilled with the aid of neuro-navigation,which could avoid the bewilder in drilling process.The angles of visual field,the length of clivus andⅦcranial nerve were significantly increased after partial labyrinthectomy with petrous apicectomy or all labyrinth removal,but there were no significant difference between partial and all labyrinth removal.The retrolabyrinthine keyhole approach spares hearing and facial function but provided for limited window of petroclival region exposure.The partial labyrinthectomy with petrous apicectomy keyhole approach provided wider exposure to petroclival region,cere- bellopontine angle,prepontine region and posterior cavernous sinus;an area between theⅢ-XI cranial nerves was easily visible with an excellent chance of hearing and facial nerve preservation.The translabyrin- thine keyhole approach,producing more morbidity,provided for greater versatility in treating lesions,added little exposure of petroclival region.Conclusion The presigmoid translabyrinthine keyhole approach,which could provide excellent exposure of the petroclival region,was feasible to be performed in our study.The ap- proach-correlated bone could be precisely removed assisted by neuro-navigation system.The exposure was oh- viously increased hy partial labyrinthectomy with petrous apicectomy or all labyrinthine removal,the former provided an excellent chancre of hearing and facial nerve preservation.

Microsurgical anatomy on the design of the far-lateral supracondylar keyhole approach / 中华显微外科杂志

Objective To explore the posibility of removing the jugular tubercle precisely and design a new far-lateral supraeondylar keyhole approach based on keyhole idea.Methods Eight cadaveric heads fixed by 10% formalin and perfused intracranial vessels with colored silicone were used in this study.Before the operation,navigation data of these cadaveric heads were established and circumscriptions of jugular tuber- cle were outlined in the navigation system in order to aid drilling it in operation.A 7cm longitudinal“S”shaped skin incision as we reported was performed.After inverting suboccipital muscles and exposing the far lateral of the occipital bone,occipital condyle,jugular tubercle,hemilamina of C_1,vertebral artery and pos- terolateral portion of foramen magnum,a 3cm retro-condylar bone window was made.Under the microscope, anatomic structures were observed and important structures were measured after jugular tubercle removal assis- ted by neuro-navigation.Results The 7cm longitudinal“S”shaped skin incision with its superior border 2cm behind the middle point of mastoid and inferior margin at the level of C_2 can fully meet the needs of the far-lateral supracondylar keyhole approach;jugular tubercle can be drilled satisfactorily with the help of neuro- navigation;inferior segment of basilar artery[long(15.65?1.34)mm]and anterior inferior cerebellar artery [long(20.36?4.18)mm] can be exposed.Conchlsion Owing to the area of middle clivus is increasingly exposed after removal of jugular tubercle,it is feasible to perform the far-lateral supracondylar keyhole ap- proach on the operations of vertebral-basilar artery aneurysm,anterior inferior cerebellar artery aneurysm and tumor located inferior and middle clivi or jugular foramen.

Microsurgical Anatomy of the Middle Cerebral Artery

The microsurgical anatomy of the middle cerebral artery(MCA) was reviewed. Embryology, segments, major branches, perforating branches, anomalies of the MCA and the anatomy of the Sylvian fissure were summarized.

Microsurgical Anatomy of the Choroidal Fissure

The authors had studied the microsurgical anatomy of the choroidal fissure and the operative approaches directed through the fissure. In this study, eight formalin-fixed cadaveric hemisheres were examined. In four hemispheres, the intracranial vessels were perfused with colored silicone latex. The choroidal fissure is divided into three portion : (a) body portion, (b) atrial portion, and (c) temporal portion. Dissection through the body portion of the choroidal fissure exposes the velum interpositum, internal cerebral vein, and third ventricle. The quadrigeminal cistern, pineal region, and posterior part of the ambient cistern can be exposed through the atrial portion of the choroidal fissure. Opening through the temporal portion of the choroidal fissure exposes the structures in the ambient cistern, which include the basal vein, posterior cerebral artery, anterior and lateral posterior choroidal arteries, and hippocampal formation. This study provides valuable knowledges of microsurgical approaches to the third ventricle and basal cistern by demonstrating the neural nd vascular relaionship around the choroidal fissure.