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This article compares the minipterional (MPT) and supraorbital eyebrow (SE) approaches to the parasellar region in neurosurgery. The study used cadaveric specimens to evaluate the exposures and anatomical indications of both approaches. The results showed that both approaches provided sufficient exposure along the ipsilateral parasellar region, but the viewing angle was significantly different. The MPT approach allowed for early access to the ipsilateral neurovascular structures, while the SE approach provided direct access to the anterior skull base and parasellar region bilaterally. The article concludes that both approaches minimize manipulation of the temporal muscle and may decrease retraction of brain parenchyma, but the SE approach is recommended for lesions requiring early proximal vascular control and access to the contralateral parasellar region. [Extracted from the article]

This article, published in the Journal of Neurological Surgery, provides a comprehensive anatomical overview and comparison of different surgical approaches to the petrous apex. The authors performed transcranial and endoscopic endonasal approaches on specimens and took 3D images at each step. The transcranial approaches included anterior petrosectomy, transcochlear approach, and retrosigmoid approach, while the endoscopic approaches included transclival-transcavernous approach, transmaxillary-transpterygoid approach, and contralateral transmaxillary approach. The article concludes by describing the different exposures of the petrous apex and related structures through these approaches. [Extracted from the article]

The article discusses the Retrosigmoid Approach with Endoscopic-Assisted Reverse Anterior Petrosectomy (RAP), a surgical technique used to treat lesions in the brain. The study examines the extent of access to Meckel's cave (MC) and the middle cranial fossa (MCF) during the procedure and provides guidance for protecting the internal carotid artery (ICA). The researchers performed dissections on anatomical specimens and measured various distances to MC and ICA. The results suggest that extended inferolateral drilling of the petrous apex provides greater access to MC, but carries a higher risk of injury to the ICA. The article recommends drilling in an anterior and superior direction to achieve better MCF access and avoid ICA injury. [Extracted from the article]

This article, titled "Relevance of the Cochlear Aqueduct in Presigmoid Approaches: A Radio-Anatomical Study," explores the role of the cochlear aqueduct (CA) in presigmoid surgery. The CA is a bony canal that drains perilymph from the cochlea. The study examines whether the CA can serve as a reference for determining the height of the jugular bulb (JB) in presigmoid approaches. The researchers performed surgical approaches on cadaveric heads and analyzed CT scans of patients. They found that the presence of a supra-jugular CA predicted a larger presigmoid window and better access to prepontine structures. The CA's relationship to the JB can be discerned on preoperative CT scans, which may help surgeons decide whether to use a presigmoid approach. [Extracted from the article]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Introduction  The middle fossa (MF) approaches encompass a group of versatile surgical accesses to pathologies in the MF, internal auditory canal (IAC), and superomedial aspect of the posterior fossa. Although many descriptions of the MF approaches have been published, a practical surgical guide that allows an easy understanding for Skull Base trainees is needed. Methods  Three formalin-fixed, colored-injected specimens were dissected under microscopic magnification (six sides). A MF craniotomy followed by IAC drilling was performed on three sides, and anterior petrosectomy (AP) was performed in the remaining three sides. The anatomical dissection was documented in stepwise three-dimensional photographic images. Following dissection, representative case applications were reviewed. Results  The MF approach provides direct access to the MF structures and IAC. The AP provides excellent access to the superomedial aspect of the posterior fossa. Key common steps include: positioning and skin incision; scalp and muscle flaps; burr holes; craniotomy flap elevation; dural dissection along the petrous ridge; division of the middle meningeal artery; and exposure of the greater superficial petrosal nerve, tegmen tympani, and V3. Then, to approach the IAC: superior IAC drilling, and longitudinal dura opening. The area drilled in the AP approach forms a pentagon limited by the petrous internal carotid artery, cochlea, IAC, petrous ridge, and lateral border of V3. Conclusion  The MF approaches are challenging. Operatively oriented skull base dissections provide a crucial foundation for learning these techniques. We describe comprehensive step-by-step approaches intended to develop familiarity in the cadaver laboratory and facilitate understanding of their potential for skull base disorders. Basic surgical principles are described to help in the operating room as well as illustrative cases. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]