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White matter dissection (WMD) involves isolating bundles of myelinated axons in the brain and serves to gain insights into brain function and neural mechanisms underlying neurological disorders. While effective, cadaveric brain dissections pose certain challenges mainly due to availability of resources. Technological advancements, such as photogrammetry, have the potential to overcome these limitations by creating detailed three-dimensional (3D) models for immersive learning experiences in neuroanatomy. This study aimed to provide a detailed step-by-step WMD captured using two-dimensional (2D) images and 3D models (via photogrammetry) to serve as a comprehensive guide for studying white matter tracts of the brain. One formalin-fixed brain specimen was utilized to perform the WMD. The brain was divided in a sagittal plane and both cerebral hemispheres were stored in a freezer at -20 °C for 10 days, then thawed under running water at room temperature. Micro-instruments under an operating microscope were used to perform a systematic lateral-to-medial and medial-to-lateral dissection, while 2D images were captured and 3D models were created through photogrammetry during each stage of the dissection. Dissection was performed with comprehensive examination of the location, main landmarks, connections, and functions of the white matter tracts of the brain. Furthermore, high-quality 3D models of the dissections were created and housed on SketchFab®, allowing for accessible and free of charge viewing for educational and research purposes. Our comprehensive dissection and 3D models have the potential to increase understanding of the intricate white matter anatomy and could provide an accessible platform for the teaching of neuroanatomy.
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OBJECTIVE: Several pathologies either invade or arise within the orbit. These include meningiomas, schwannomas, and cavernous hemangiomas among others. Although several studies describing various approaches to the orbit are available, no study describes all cranio-orbital and orbitocranial approaches with clear, surgically oriented anatomical descriptions. As such, this study aimed to provide a comprehensive guide to the microsurgical and endoscopic approaches to and through the orbit. METHODS: Six formalin-fixed, latex-injected cadaveric head specimens were dissected in the surgical anatomy laboratory at the authors' institution. In each specimen, the following approaches were modularly performed: endoscopic transorbital approaches (ETOAs), including a lateral transorbital approach and a superior eyelid crease approach; endoscopic endonasal approaches (EEAs), including those to the medial orbit and optic canal; and transcranial approaches, including a supraorbital approach, a fronto-orbital approach, and a 3-piece orbito-zygomatic approach. Each pertinent step was 3D photograph-documented with macroscopic and endoscopic techniques as previously described. RESULTS: Endoscopic endonasal approaches to the orbit afforded excellent access to the medial orbit and medial optic canal. Regarding ETOAs, the lateral transorbital approach afforded excellent access to the floor of the middle fossa and, once the lateral orbital rim was removed, the cavernous sinus could be dissected and the petrous apex drilled. The superior eyelid approach provides excellent access to the anterior cranial fossa just superior to the orbit, as well as the dura of the lesser wing of the sphenoid. Craniotomy-based approaches provided excellent access to the anterior and middle cranial fossa and the cavernous sinus, except the supraorbital approach had limited access to the middle fossa. CONCLUSIONS: This study outlines the essential surgical steps for major cranio-orbital and orbitocranial approaches. Endoscopic endonasal approaches offer direct medial access, potentially providing bilateral exposure to optic canals. ETOAs serve as both orbital access and as a corridor to surrounding regions. Cranio-orbital approaches follow a lateral-to-medial, superior-to-inferior trajectory, progressively allowing removal of protective bony structures for proportional orbit access.
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Procedimientos Neuroquirúrgicos , Órbita , Humanos , Procedimientos Neuroquirúrgicos/métodos , Órbita/cirugía , Endoscopía/métodos , Fosa Craneal Media/cirugía , Craneotomía/métodos , CadáverRESUMEN
PURPOSE: A detailed understanding of the neurovascular relationships between the optic nerve (ON) and the ophthalmic artery (OA) in the optic canal (OC) is paramount for safe surgery. We focused on the neurovascular anatomy of this area from both an endoscopic endonasal and transcranial trajectories to compare the surgical exposures and perspectives offered by these different views and provide recommendations to increase the intraoperative safety. METHODS: Twenty sides of ten formalin-fixed, latex-injected head specimens were utilized. The surgical anatomy and anatomical relationships of the OA in relationship to the ON along their intracranial and intracanalicular segments was studied from endoscopic endonasal and transcranial perspectives. RESULTS: Three types of OA-ON relationships at the origin of the OA were identified: inferomedial (type 1, 35%), inferior (type 2, 55%), and inferolateral (type 3, 10%). The endoscopic endonasal trajectory offers an inferomedial perspective of the ON-OA neurovascular complex, in which the OA, especially when located inferomedially, is first encountered. When comparing with the transcranial view, all OA were covered by the nerve, type 1 was located below the medial third, type 2 below the middle third, and type 3 below the lateral third of the OC. The mean extension of the intracanalicular portion of both OA and ON was 8.9 mm, while the intracranial portion of the OA and ON were 9.3 mm and 12.4 mm, respectively. The OA, endoscopically, is located within the inferior half of the OC, and occupies 39%, 43%, and 42% of the OC height at its origin, mid, and end points, respectively. The mean distance between the superior margin of the OC at its origin and superior margin of the OA is 1.4 mm. CONCLUSIONS: Detailed anatomical understanding of the OC, and the ON and OA at their intracranial and intracanalicular segments is paramount to safe surgery. When opening the OC dura endoscopically, our results suggest that a medial incision along the superior third of the OC with a proximal to distal direction is recommended to avoid injury of the OA.
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Endoscopía , Arteria Oftálmica , Humanos , Arteria Oftálmica/cirugía , Arteria Oftálmica/anatomía & histología , Cadáver , Endoscopía/métodos , Nariz , Nervio Óptico/cirugía , Nervio Óptico/anatomía & histologíaRESUMEN
PURPOSE: The anatomy of the medial wall of the cavernous sinus (MWCS) and parasellar ligaments (PLs) has acquired increasing importance in endoscopic endonasal (EE) surgery of the cavernous sinus (CS), including resection of the MWCS in functioning pituitary adenomas (FPAs). Although anatomical studies have been published, it represents a debated topic due to their complex morphology. The aim is to offer a description of the PLs that originate from the MWCS and reach the lateral wall of the cavernous sinus (LWCS), proposing the "candy wrapper" model. The relationships between the neurovascular structures and histomorphological aspects were investigated. METHODS: Forty-two CSs from twenty-one human heads were studied. Eleven specimens were used for EE dissection; five underwent a microscopic dissection. Five specimens were used for histomorphological analysis. RESULTS: Two groups of PLs with a fan-shaped appearance were encountered. The anterior group included the periosteal ligament (55% sides) and the carotico-clinoid complex (100% sides), formed by the anterior horizontal and the carotico-clinoid ligaments. The posterior group was formed by the posterior horizontal (78% sides), and the inferior hypophyseal ligament (34% sides). The periosteal ligament originated inferiorly from the MWCS, reaching the periosteal dura. The anterior horizontal ligament was divided in a superior and inferior branch. The superior one continued as the carotid-oculomotor membrane, and the inferior branch reached the CN VI. The carotico-clinoid ligament between the middle and anterior clinoid was ossified in 3 sides. The posterior horizontal ligament was related to the posterior genu and ended at the LWCS. The inferior hypophyseal ligament followed the homonym artery. The ligaments related to the ICA form part of the adventitia. CONCLUSION: The "candy wrapper" model adds further details to the previous descriptions of the PLs. Understanding this complex anatomy is essential for safe CS surgery, including MWCS resection for FPAs.
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Seno Cavernoso , Neoplasias Hipofisarias , Humanos , Seno Cavernoso/cirugía , Hipófisis/cirugía , Hipófisis/anatomía & histología , Arterias Carótidas , Neoplasias Hipofisarias/cirugía , Ligamentos/cirugíaRESUMEN
PURPOSE: To create a high-quality, cadaver-based, operatively oriented resource documenting the anterior transcortical and interhemispheric transcallosal approaches as corridors to the third ventricle targeted towards neurosurgical trainees at all levels. METHODS: Two formalin-fixed, latex-injected specimens were dissected under microscopic magnification and endoscopic-assisted visualization. Dissections of the transcortical and transcallosal craniotomies with transforaminal, transchoroidal, and interforniceal transventricular approaches were performed. The dissections were documented in a stepwise fashion using three-dimensional photographic image acquisition techniques and supplemented with representative cases to highlight pertinent surgical principles. RESULTS: The anterior transcortical and interhemispheric corridors afford excellent access to the anterior two-thirds of the third ventricle with varying risks associated with frontal lobe versus corpus callosum disruption, respectively. The transcortical approach offers a more direct, oblique view of the ipsilateral lateral ventricle, whereas the transcallosal approach readily establishes biventricular access through a paramedian corridor. Once inside the lateral ventricle, intraventricular angled endoscopy further enhances access to the extreme poles of the third ventricle from either open transcranial approach. Subsequent selection of either the transforaminal, transchoroidal, or interforniceal routes can be performed through either craniotomy and is ultimately dependent on individual deep venous anatomy, the epicenter of ventricular pathology, and the concomitant presence of hydrocephalus or embryologic cava. Key steps described include positioning and skin incision; scalp dissection; craniotomy flap elevation; durotomy; transcortical versus interhemispheric dissection with callosotomy; the aforementioned transventricular routes; and their relevant intraventricular landmarks. CONCLUSIONS: Approaches to the ventricular system for maximal safe resection of pediatric brain tumors are challenging to master yet represent foundational cranial surgical techniques. We present a comprehensive operatively oriented guide for neurosurgery residents that combines stepwise open and endoscopic cadaveric dissections with representative case studies to optimize familiarity with third ventricle approaches, mastery of relevant microsurgical anatomy, and preparation for operating room participation.
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Neoplasias Encefálicas , Tercer Ventrículo , Humanos , Niño , Tercer Ventrículo/cirugía , Tercer Ventrículo/anatomía & histología , Ventrículos Cerebrales/cirugía , Ventrículos Cerebrales/anatomía & histología , Procedimientos Neuroquirúrgicos/métodos , Ventrículos Laterales/cirugía , Neoplasias Encefálicas/cirugía , Cuerpo Calloso/cirugía , Cuerpo Calloso/anatomía & histologíaRESUMEN
BACKGROUND: Classically, the transtuberculum and transplanum approaches have been utilized to reach the suprachiasmatic and infrachiasmatic corridors. The aim of this study was to provide a better understanding of the key endoscopic endonasal anatomy of the suprachiasmatic and infrachiasmatic corridors provided through selective removal of the prechiasmatic sulcus (SRPS). METHOD: A SRPS was performed in 16 sides of 8 alcohol-fixed head specimens. Twenty anatomical measurements were collected on the suprachiasmatic and infrachiasmatic corridors. The transplanum and transtuberculum approaches were also performed. RESULTS: In the suprachiasmatic corridor, the SRPS exposed the anterior communicating artery (AComm) and the post-communicating segment of the anterior cerebral arteries in all the cases, while the pre-communicating segment of the anterior cerebral arteries, recurrent arteries of Heubner, and fronto-orbital arteries were visualized in 75% (12/16), 31% (5/16), and 69% (11/16) of cases, respectively. In the infrachiasmatic corridor, the ophthalmic segment of the internal carotid artery and superior hypophyseal arteries were always visible through the SRPS. The mean width and height of the prechiasmatic sulcus were 13.2 mm and 9.6 mm, respectively. The mean distances from the midpoint of the AComm to the anterior margin of the optic chiasm (OCh) was 5.3 mm. The mean width of the infrachiasmatic corridor was 12.3 mm at the level of the proximal margin of the ophthalmic segment of the internal carotid artery. The mean distances from the posterior superior limit of the pituitary stalk to the basilar tip and oculomotor nerve were 9.7 mm and 12.3 mm, respectively. CONCLUSIONS: The SRPS provides access to the main neurovascular and cisternal surgical landmarks of the suprachiasmatic and infrachiasmatic corridors. This anatomical area constitutes the key part of the approach to the suprasellar area. To afford adequate surgical maneuverability, the transplanum or transtuberculum approaches are usually a necessary extension.
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Neuroendoscopía , Arteria Cerebral Anterior/anatomía & histología , Cadáver , Endoscopía , Humanos , Nariz , Quiasma Óptico/anatomía & histología , Quiasma Óptico/cirugía , Hipófisis/anatomía & histologíaRESUMEN
BACKGROUND: The pineal region and dorsal midbrain are among the most challenging surgical targets. To approach lesions in this region that harbor a superior to inferior long axis, we describe the basic steps of the precuneal, interhemispheric, trans-tentorial approach and illustrate anatomical landmarks of this established, but not so popular, surgical trajectory. METHOD: To study the anatomical landmarks and safety of this approach, the neurovascular anatomy was studied on 22 sides of 11 formalin-fixed latex-injected anatomical specimens. A step-by-step dissection of the precuneal interhemispheric trans-tentorial approach and study of the key anatomical landmarks was performed. An illustrative clinical case of a pontomesencephalic cavernous malformation (CM) resected through this approach is also detailed. RESULTS: The mean distance from the transverse sinus to the most posterior cortical vein draining into the superior sagittal sinus was 6.4 cm. The mean distance from the calcarine sulcus to the most posterior cortical vein was 5.3 cm. Key steps of the dissection are as follows: craniotomy exposing the posterior aspect of the superior sagittal sinus (SSS), durotomy and gentle retraction of the SSS edge, dissection of the interhemispheric fissure, linear incision of the tentorium that extends anteriorly to the incisura and lateral reflection of the tentorium, and arachnoidal dissection and exposure of the cerebellomesencephalic fissure. CONCLUSION: The precuneal, interhemispheric, trans-tentorial approach affords excellent access to the falcotentorial junction, splenium, pineal region, quadrigeminal cistern, and dorsal pons once the cerebellomesencephalic fissure has been dissected.
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Procedimientos Neuroquirúrgicos , Glándula Pineal , Tronco Encefálico , Duramadre/cirugía , Humanos , Neuronavegación , Procedimientos Neuroquirúrgicos/métodos , Glándula Pineal/cirugíaRESUMEN
PURPOSE: Traditional endoscopic endonasal approaches to the cavernous sinus (CS) open the anterior CS wall just medial to the internal carotid artery (ICA), posing risk of vascular injury. This work describes a potentially safer midline sellar entry point for accessing the CS utilizing its connection with the inferior intercavernous sinus (IICS) when anatomically present. METHODS: The technique for the midline intercavernous dural access is described and depicted with cadaveric dissections and a clinical case. RESULTS: An endoscopic endonasal approach exposed the periosteal dural layer of anterior sella and CS. The IICS was opened sharply in midline through its periosteal layer. The feather knife was inserted and advanced laterally within the IICS toward the anterior CS wall, thereby gradually incising the periosteal layer of the IICS. The knife was turned superiorly then inferiorly in a vertical direction to open the anterior CS wall. This provided excellent access to the CS compartments, maintained the meningeal layer of the IICS and the medial CS wall, and avoided an initial dural incision immediately adjacent to the ICA. CONCLUSION: The midline intercavernous dural access to the CS assisted by a 90° dissector-blade is an effective modification to previously described techniques, with potentially lower risk to the ICA.
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Seno Cavernoso , Cadáver , Seno Cavernoso/cirugía , Humanos , NarizRESUMEN
OBJECTIVE: There is a void in the literature describing reliable surgical landmarks that aid in the dissection of the facial recess in the absence of skeletonizing the mastoid segment of the facial nerve. The posterior ligament of the incus is a readily distinguishable "white dot" along the incus buttress that has been used to guide dissection in a safe and efficient manner. The goal of our study is to describe a surgical approach that utilizes this surgical landmark to drill the facial recess and to take anatomical measurements demonstrating the safety and reliability of this approach. MATERIALS AND METHODS: After cortical mastoidectomies were performed in 10 cadaveric temporal bones, the white dot was identified at the junction of short process of the incus and the incus buttress. Using the white dot for anatomical reference, a 2 mm diamond drill bit was used to open the facial recess without first identifying the facial nerve or chorda tympani nerve. After photographs were taken, the facial and chorda tympani nerves were definitively identified and skeletonized to delineate the confines of the facial recess. Photographs were once again acquired in a consistent manner for comparison. Finally, calibrated anatomic measurements were acquired from the 10 distinct image sets. RESULTS: The facial recess was successfully drilled in 10 temporal bones using the posterior ligament as a surgical landmark without injury to the chorda tympani or facial nerve. The median angle taken from the axis of the short process of the incus to the facial nerve - chorda tympani junction was 139.2° (IQR 136.8-141). At the widest point in the facial recess, median distances anterior and posterior to an imaginary line connecting the white dot to the facial nerve - chorda tympani junction were 1.6 mm (IQR 1.5-1.7) and 1.6 mm (IQR 1.6-1.7; p = 0.57), indicating at this point, the white dot reference reliably bisects the facial recess width. Similarly, at the level of the round window niche, median anterior and posterior distances from an imaginary line connecting the white dot to the facial nerve - chorda tympani junction were 1.1 mm (IQR 1.1-1.3) and 1.3 mm (IQR 1.1-1.7; p = 0.07), respectively, once again demonstrating the white dot reliably bisecting the facial recess. CONCLUSIONS: The white dot, representing the posterior ligament of the incus, is a reliable surgical landmark that aids in safe and efficient drilling of the facial recess without first skeletonizing the facial nerve.
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Implantación Coclear , Yunque , Nervio de la Cuerda del Tímpano/cirugía , Implantación Coclear/métodos , Nervio Facial/cirugía , Humanos , Yunque/cirugía , Ligamentos/cirugía , Reproducibilidad de los Resultados , Ventana Redonda/cirugía , Hueso Temporal/cirugíaRESUMEN
PURPOSE OF THE STUDY: Several tissues have been decellularized and their extracellular matrices used as allogeneic or xenogeneic scaffolds, either in orthotopic or heterotopic implantations, for tissue engineering purposes. Placentas have abundant matrix, extensive microvascular structure, immunomodulatory properties, growth factors and are discarded after birth, representing an interesting source of extracellular matrix. This study aimed at comparing decellularized canine placentas and murine skeletal muscles to regenerate skeletal muscles in a rat model. MATERIALS AND METHODS: Muscle pockets were created at the posterior limbs of male Wistar rats, where the muscle- and placenta-derived extracellular matrices were implanted. Macroscopic, histological, and immunohistochemical analyses were performed after 3, 15, and 45 days of surgeries. RESULTS: On the third day, intense inflammatory reaction, with macrophages (CD163+) and proliferative cells (PCNA+) being observed in control group and adjacent to the decellularized matrices. The percentage of proliferative cells was higher in placenta than in muscle matrices. Macrophages CD163+ high were higher in muscles than in placentas, whereas CD163+ low were higher in placentas than in muscle ECM, at days 3 and 15. Placental matrices were not completely degraded at day 15, as opposed to the muscular ones. After 45 days, both matrices were resorbed and morphologically normal myofibers, with reduction of cell infiltration, were observed. CONCLUSIONS: These results demonstrated that xenogeneic placental ECM, implanted heterotopically (representing a biologically critical and challenging microenvironment), induced local inflammatory reactions similar to the allogeneic muscle ECM, implanted orthotopically. Thus, placenta-derived extracellular matrix must be further explored in regenerative medicine.
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Placenta , Andamios del Tejido , Animales , Perros , Matriz Extracelular/metabolismo , Femenino , Masculino , Ratones , Músculo Esquelético , Embarazo , Ratas , Ratas Wistar , Ingeniería de Tejidos/métodos , Andamios del Tejido/químicaRESUMEN
Volumetric muscle loss causes functional weakness and is often treated with muscle grafts or implant of biomaterials. Extracellular matrices, obtained through tissue decellularization, have been widely used as biological biomaterials in tissue engineering. Optimal decellularization method varies among tissues and have significant impact on the quality of the matrix. This study aimed at comparing the efficacy of four protocols, that varied according to the temperature of tissue storage and the sequence of chemical reagents, to decellularize murine skeletal muscles. Tibialis anterior muscles were harvested from rats and were frozen at -20°C or stored at room temperature, followed by decellularization in solutions containing EDTA + Tris, SDS and Triton X-100, applied in different sequences. Samples were analyzed for macroscopic aspects, cell removal, decrease of DNA content, preservation of proteins and three-dimensional structure of the matrices. Processing protocols that started with incubation in SDS solution optimized removal of cells and DNA content and preserved the matrix ultrastructure and composition, compared to those that were initiated with EDTA + Tris. Freezing the samples before decellularization favored cell removal, regardless of the sequence of chemical reagents. Thus, to freeze skeletal muscles and to start decellularization with 1% SDS solution showed the best results.
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Ingeniería de Tejidos , Andamios del Tejido , Animales , Matriz Extracelular , Ratones , Músculo Esquelético , Octoxinol , RatasRESUMEN
The onset of gestation is characterized by growth, morphological and functional changes of the placenta. We aim to evaluate the placental compartments in New Zealand rabbits by means of stereological methods. The fetal and maternal portion of placenta (12, 14, 18 and 20 gestational days) was randomly sampled for the stereological analysis. Histological sections were scanned to estimate fetal (labyrinth and junctional) and maternal (decidua) compartment volumes. The total volume of the placenta for the ages of 12, 14, 18 and 20 days was, respectively, 320 mm3, 340 mm3, 940 mm3 and 1300 mm3. The volume of the labyrinth was 56 mm3, 119 mm3, 231 mm3 and 481 mm3, respectively. The volume of junctional zone was 75 mm3, 76 cm3, 238 mm3 and 314 mm3, respectively. The volume of decidua was 174 mm3, 143 mm3, 469 mm3 and 504 mm3, respectively. We concluded that the rabbit´s placenta compartments varied according to the gestational period, increasing continuously over the 20 gestational days. However, on the onset of the development of the placenta the decidua presented faster growth, whereas after the 20 days of development, the labyrinth developed more quickly. This study represents an aid to the understanding of placentation in humans.
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Placenta , Placentación , Animales , Femenino , Feto , Embarazo , ConejosRESUMEN
Although the sphenoidal emissary foramen (SEF) and its content are anatomically and clinically relevant, accurate description of them in the modern literature is lacking. This study aimed to examine and describe the SEF and its content (the sphenoidal emissary vein [SEV]). We analyzed 1,000 computed tomography (CT) images, 170 dry skulls, 50 formalin-fixed specimens, and three specimens (heads) following guidelines proposed by Dr. Albert L. Rhoton Jr. MD for latex injection. SEV morphology was determined by histological staining and electron microscopy. The SEF was observed in 46.8% of the CTs studied (25.4% bilateral and 21.4% unilateral), and 45.2% of the dry skulls (18.8% bilateral and 26.4% unilateral). In 9.5% of CTs and 21.1% of dry skulls there was a blind channel in the external surface of the cranial base; since there was no communication with the cranial cavity, it was not considered as the SEF. During the dissections, the SEF was found in seven individuals. In three of them, the SEV was an alternative route for venous drainage of the venous plexus of the foramen ovale. Its walls were composed of collagen fibers and its endothelium contained rhomboid cells resembling those commonly found in the superior sagittal sinus. The presence of the SEF and SEV can anatomically explain the spread of certain cranial base pathologies from or toward Meckel's cave or the cavernous sinus, and should be taken into account during procedures in the middle cranial fossa, percutaneous approaches, odontological procedures, and treatment of dural arteriovenous fistulas. Clin. Anat., 33:767-781, 2020. © 2019 Wiley Periodicals, Inc.
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Senos Craneales/anatomía & histología , Senos Craneales/diagnóstico por imagen , Base del Cráneo/anatomía & histología , Base del Cráneo/diagnóstico por imagen , Hueso Esfenoides/anatomía & histología , Hueso Esfenoides/diagnóstico por imagen , Adulto , Anciano , Anciano de 80 o más Años , Cadáver , Disección , Humanos , Persona de Mediana Edad , Tomografía Computarizada por Rayos XRESUMEN
The placenta is a temporal, dynamic and diverse organ with important immunological features that facilitate embryonic and fetal development and survival, notwithstanding the fact that several aspects of its formation and function closely resemble tumor progression. Placentation in mammals is commonly used to characterize the evolution of species, including insights into human evolution. Although most placentas are discarded after birth, they are a high-yield source for the isolation of stem/progenitor cells and are rich in extracellular matrix (ECM), representing an important resource for regenerative medicine purposes. Interactions among cells, ECM and bioactive molecules regulate tissue and organ generation and comprise the foundation of tissue engineering. In the present article, differences among several mammalian species regarding the placental types and classifications, phenotypes and potency of placenta-derived stem/progenitor cells, placental ECM components and current placental ECM applications were reviewed to highlight their potential clinical and biomedical relevance.
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Matriz Extracelular/fisiología , Placenta/citología , Placenta/embriología , Medicina Regenerativa , Células Madre/citología , Ingeniería de Tejidos , Animales , Diferenciación Celular/fisiología , Femenino , Humanos , Placenta/fisiología , Placentación/fisiología , EmbarazoRESUMEN
PURPOSE OF REVIEW: The purpose of this review is to provide a comprehensive anatomical appraisal of the neurosurgical anatomy exposed through the endonasal and paranasal sinuses routes, focusing on the most common expanded endonasal approaches (EEAs) as well as recent advances in this surgical field. RECENT FINDINGS: The EEAs are redefining the management of skull base pathology. Neurovascular structures previously considered a limitation, can be now approached through these surgical corridors. Advances in this field include the development of new surgical techniques and routes that allow better visualization and access to pathologies located in the ventral skull base. Understanding the surgical anatomy related to EEAs is essential not only for neurosurgeons but also for rhinologists. SUMMARY: Knowledge of the surgical anatomy of the most common EEAs that utilize paranasal sinuses as a surgical corridor enables more effective management of complex skull base pathologies. Comprehensive anatomical knowledge of these corridors and the surrounding neurovascular structures is crucial to maximize benefits of EEAs and improve outcomes.
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Neurocirugia , Senos Paranasales , Humanos , Procedimientos Neuroquirúrgicos , CabezaRESUMEN
The careers of the Mayo brothers, Harvey Cushing, and Sir William Osler greatly shaped medical and surgical practice in the late 19th century and early 20th century and created a legacy to influence decades of physicians to follow. Additionally, these individuals were instrumental in the founding of neurosurgery as a distinct surgical specialty. Alongside these great men, Dr. Albert L. Rhoton Jr., revolutionized neurosurgical practice through his study of neuroanatomy and development of microsurgical technique in the second half of the 20th century. This review of the interactions and relationships between the Mayo brothers, Cushing, and Osler and their influences on Rhoton highlights the 100-year-long interconnectedness shared between these giants in the history of neurosurgery.
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Neurocirugia , Médicos , Masculino , Humanos , Neurocirugia/historia , Procedimientos Neuroquirúrgicos/historia , NeuroanatomíaRESUMEN
BACKGROUND AND OBJECTIVES: The infratemporal fossa (ITF) is a complex region bounded by the temporal bone, maxilla, sphenoid, pterygoid plates, and mandibular ramus. Containing a high density of neurovascular and musculoskeletal structures, the ITF can house a number of pathologies, and access is challenging. The ITF approach and its variations can be challenging due to complex anatomy and unfamiliarity by many surgeons. The objective of this study was to present a step-by-step 3-dimensional anatomic dissection for the classic Fisch Type A and modified ITF approach from the surgeon's perspective. METHODS: Six sides of 3 formalin-fixed latex-injected specimens were dissected under microscopic magnification (JRD and AMN). Standard Fisch Type A and modified ITF approaches were performed on contralateral sides of each specimen. Representative high-quality 3-dimensional photography was performed for each key step. RESULTS: The ITF approach affords excellent access to the posterior ITF and jugular foramen. Modifications to this approach include preservation of the ear canal and limiting facial nerve transposition, thus limiting morbidity while generally still providing sufficient access to key anatomic structures. CONCLUSION: The ITF approach provides access to the lateral skull base for jugular foramen paraganglioma and other lesions. Modifications of the classic Fisch Type A technique can be used to access pathologies in this region without sacrificing conductive hearing or facial nerve function. Three dimensional operatively oriented neuroanatomy dissections provide surgeons with a valuable resource for learning this complex surgical approach.
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Fosa Infratemporal , Foramina Yugular , Humanos , Base del Cráneo/anatomía & histología , Disección , Procedimientos NeuroquirúrgicosRESUMEN
Introduction Although many neuroanatomic atlases have been published, few have detailed complex cranial approaches and pertinent anatomic considerations in a stepwise fashion intended for rapid comprehension by neurosurgery students, residents, and fellows. Methods Five sides of formalin-fixed latex-injected specimens were dissected under microscopic magnification. The frontotemporal and orbitozygomatic approaches were performed by neurosurgical residents and fellows at different training levels with limited previous experience in anatomical dissection mentored by the senior authors (M.P.C. and M.J.L.). Meticulous surgical anatomic dissections were performed until sufficient visual and technical completion was attained, with parameters of effectively demonstrating key surgical steps for educational training purposes. Following the completion of dissection and three-dimensional photography, illustrative case examples were reviewed to demonstrate the relative benefits and optimal applications of each approach. Results The frontotemporal and orbitozygomatic approaches afford excellent access to anterior and middle skull base pathologies, as well as the exposure of the infratemporal fossa. Key considerations include head positioning, skin incision, scalp retraction, fat pad dissection and facial nerve protection, true or false MacCarty keyhole fashioning, sphenoid wing drilling and anterior clinoidectomy, completion of the craniotomy and accessory orbital osteotomy cuts, dural opening, and intradural neurovascular access. Conclusion The frontotemporal and orbitozygomatic approaches are core craniotomies that offer distinct advantages for complex cranial operations. Learning and internalizing their key steps and nuanced applications in a clinical context is critical for trainees of many levels. The orbitozygomatic craniotomy in particular is a versatile but challenging approach; operative-style laboratory dissection is an essential component of its mastery and one that will be powerfully enhanced by the current work.
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Frontal sinus surgery still represents a challenge due to its complex and highly variable anatomy. In this manuscript, we present a detailed anatomical description of an eyebrow approach that allows full exposure of the frontal sinus with a large osteoplastic bone flap and preservation of the supraorbital nerve. Laryngoscope, 134:1633-1637, 2024.
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Seno Frontal , Neoplasias de los Senos Paranasales , Procedimientos de Cirugía Plástica , Humanos , Seno Frontal/cirugía , Cejas , Neoplasias de los Senos Paranasales/cirugía , Órbita/cirugíaRESUMEN
Introduction The endoscopic endonasal transpterygoid approach (EETPA) with or without the addition of the endoscopic-assisted sublabial anterior transmaxillary approach (ESTA) has become increasingly utilized for lesions posterior to the pterygopalatine fossa (PPF), including infratemporal fossa (ITF), lateral recess of the sphenoid sinus, Meckel's cave, petrous apex, and parapharyngeal space. The main goal of this study is to develop an educational resource to learn the steps of the EETPA for trainees. Methods EETPA and ESTA were performed in 12 specimens by neurosurgery trainees, under supervision from the senior authors. One EETPA and one ESTA were performed on each specimen on opposite sides. Dissections were supplemented with representative cases. Results After a wide unilateral sphenoidotomy, ethmoidectomy, and partial medial maxillectomy, the anteromedial bone limits of the PPF were identified and drilled out. The pterygoid progress was modularly removed. By enlarging the opening of the posterior and lateral walls of the maxillary sinus through EETPA and ESTA, respectively, the neurovascular and muscular compartments of the PPF and ITF were better identified. The EETPA opens direct corridors to the PPF, medial ITF, middle cranial fossa, cavernous sinus, Meckel's cave, petrous apex, and internal carotid artery. If a more lateral exposure of the ITF is needed, the ESTA is an appropriate addition. Conclusion Despite the steep learning curve of the EETPA, granular knowledge of its surgical anatomy and basic surgical steps are vital for those advancing their learning in complex endoscopic approaches to the ventral skull base when expanding the approach laterally in the coronal plane.