The Neuroanatomic Studies of Albert L. Rhoton Jr. in Historical Context: An Analysis of Origin, Evolution, and Application

Vesalius and His Manikin: An Enduring Influence on Modern Anatomic Teaching

Anatomic teaching has long informed surgical knowledge, experience, and skills. One tool for teaching that emerged during the Renaissance was the fugitive anatomic sheet, which used flap layers to reveal different levels of anatomy. In 1538, Vogtherr introduced the first fugitive sheets, which included illustrations of male and female figures with a torso paper flap that, when lifted, revealed the internal organs in a cartoonish style. The popularity of these anatomic fugitive sheets spurred an increase in small print-and-sale workshops. In 1543, Vesalius included fugitive anatomic sheets in his books Fabrica and Epitome , containing large paper flapped models that could be created by cutting out and gluing images of human internal anatomy onto a base layer. Students could tack these manikins up to a nearby wall during dissection. Significant collaboration between Vesalius and his publisher occurred to coordinate the integration of large foldable sheets featuring the cutout models into his works. Vesalius's groundbreaking discoveries, his use of the most advanced printing techniques, and his innovative teaching style are fundamental aspects of the legacy of medical education. This article shows these remarkable fugitive anatomic sheets from the original publications of Fabrica and Epitome together for the first time. It explores the innovative concepts and applications of Vesalius's unique printings.

Historical Roots of Modern Neurosurgical Cadaveric Research Practices: Dissection, Preservation, and Vascular Injection Techniques

Because of the complexity of the brain and its structures, anatomical knowledge is fundamental in neurosurgery. Anatomical dissection, body preservation, and vascular injection remain essential for training, teaching, and refining surgical techniques. This article explores the historical development of these practices and provides the contextual background of modern neurosurgical cadaveric brain models. Body preservation has ancient beginnings, evident in the Chinchorro mummifications and Egyptian embalming. However, brain preservation techniques for education were scarce until the beginning of the Renaissance in Europe. At the University of Bologna in the 13th century, occasional dissections were performed only in winter because of the lack of preservation techniques. Pope Sixtus IV's 1482 papal bull (official decree) formalized and expanded the use of dissection in medical education, leading to an explosion in anatomical studies. This surge brought advances in body preservation, such as soaking bodies in vinegar and distilled liquors. In subsequent centuries, Andreas Vesalius and Charles Bell advanced brain anatomical techniques and knowledge, combining novel illustrations and instruction. To better understand brain vasculature, Richard Lower developed vascular injection techniques using india ink and spirits of wine, leading to the 1664 description of the circle of Willis by Thomas Willis. In 1868, August Hofmann synthesized formaldehyde, markedly improving tissue preservation. Later, William Kruse introduced latex in 1939, and Sidney Sobin introduced silicone in 1965 for vascular studies. These advancements laid the foundation for modern neurosurgical cadaveric studies, many remaining relevant today.

Immersive Innovations: Exploring the Diverse Applications of Virtual Reality (VR) in Healthcare

Virtual reality (VR) has experienced a remarkable evolution over recent decades, evolving from its initial applications in specific military domains to becoming a ubiquitous and easily accessible technology. This thorough review delves into the intricate domain of VR within healthcare, seeking to offer a comprehensive understanding of its historical evolution, theoretical foundations, and current adoption status. The examination explores the advantages of VR in enhancing the educational experience for medical students, with a particular focus on skill acquisition and retention. Within this exploration, the review dissects the applications of VR across diverse medical disciplines, highlighting its role in surgical training and anatomy/physiology education. While navigating the expansive landscape of VR, the review addresses challenges related to technology and pedagogy, providing insights into overcoming technical hurdles and seamlessly integrating VR into healthcare practices. Additionally, the review looks ahead to future directions and emerging trends, examining the potential impact of technological advancements and innovative applications in healthcare. This review illuminates the transformative potential of VR as a tool poised to revolutionize healthcare practices.

Endoscopy-Assisted Microneurosurgery for Sella and Optic Foramen Invading Anterior Cranial Fossa Base Meningiomas

BACKGROUND

Anterior skull base meningioma produces symptoms as a result of mass effect and neurovascular compression. The bony anatomy of the anterior skull base is complex and houses the critical cranial nerves and vessels. Traditional microscopic approaches remove these tumors effectively but require extensive brain retraction and bone drilling. Endoscope assistance offers the advantages of a smaller incision, less brain retraction, and bone drilling. The most significant advantage of endoscope-assisted microneurosurgery for lesions invading the sella and optic foramen is the complete resection of the sellar and foraminal components frequently responsible for recurrence.

OBJECTIVE

In this report, we describe the technique of endoscope-assisted microneurosurgical resection of anterior skull base meningiomas invading the sella and foramen.

METHODS

We present 10 cases and 3 case examples of endoscope-assisted microneurosurgery for meningiomas invading the sella and optic foramen. This report presents the operating room setup and surgical details to resect sellar and foraminal tumors. The surgical procedure is presented as a video.

RESULTS

Endoscope-assisted microneurosurgery yielded excellent clinical and radiologic results and no recurrence at the last follow-up of meningiomas invading the sella and optic foramen. The present article discusses the challenges faced with endoscope-assisted microneurosurgery, techniques, and challenges in the procedure.

CONCLUSIONS

Endoscope assistance enables complete tumor excision under vision with less retraction and bone drilling in anterior cranial fossa meningioma, invading the chiasmatic sulcus, optic foramen, and sella. The mixed use of microscope and endoscope makes it safer and saves time and is like bringing out the best of both worlds.

Three-Dimensional Modeling and Extended Reality Simulations of the Cross-Sectional Anatomy of the Cerebrum, Cerebellum, and Brainstem

BACKGROUND

Understanding the anatomy of the human cerebrum, cerebellum, and brainstem and their 3-dimensional (3D) relationships is critical for neurosurgery. Although 3D photogrammetric models of cadaver brains and 2-dimensional images of postmortem brain slices are available, neurosurgeons lack free access to 3D models of cross-sectional anatomy of the cerebrum, cerebellum, and brainstem that can be simulated in both augmented reality (AR) and virtual reality (VR).

OBJECTIVE

To create 3D models and AR/VR simulations from 2-dimensional images of cross-sectionally dissected cadaveric specimens of the cerebrum, cerebellum, and brainstem.

METHODS

The Klingler method was used to prepare 3 cadaveric specimens for dissection in the axial, sagittal, and coronal planes. A series of 3D models and AR/VR simulations were then created using 360° photogrammetry.

RESULTS

High-resolution 3D models of cross-sectional anatomy of the cerebrum, cerebellum, and brainstem were obtained and used in creating AR/VR simulations. Eleven axial, 9 sagittal, and 7 coronal 3D models were created. The sections were planned to show important deep anatomic structures. These models can be freely rotated, projected onto any surface, viewed from all angles, and examined at various magnifications.

CONCLUSION

To our knowledge, this detailed study is the first to combine up-to-date technologies (photogrammetry, AR, and VR) for high-resolution 3D visualization of the cross-sectional anatomy of the entire human cerebrum, cerebellum, and brainstem. The resulting 3D images are freely available for use by medical professionals and students for better comprehension of the 3D relationship of the deep and superficial brain anatomy.

Anatomic Depth Estimation and 3-Dimensional Reconstruction of Microsurgical Anatomy Using Monoscopic High-Definition Photogrammetry and Machine Learning

BACKGROUND

Immersive anatomic environments offer an alternative when anatomic laboratory access is limited, but current three-dimensional (3D) renderings are not able to simulate the anatomic detail and surgical perspectives needed for microsurgical education.

OBJECTIVE

To perform a proof-of-concept study of a novel photogrammetry 3D reconstruction technique, converting high-definition (monoscopic) microsurgical images into a navigable, interactive, immersive anatomy simulation.

METHODS

Images were acquired from cadaveric dissections and from an open-access comprehensive online microsurgical anatomic image database. A pretrained neural network capable of depth estimation from a single image was used to create depth maps (pixelated images containing distance information that could be used for spatial reprojection and 3D rendering). Virtual reality (VR) experience was assessed using a VR headset, and augmented reality was assessed using a quick response code-based application and a tablet camera.

RESULTS

Significant correlation was found between processed image depth estimations and neuronavigation-defined coordinates at different levels of magnification. Immersive anatomic models were created from dissection images captured in the authors' laboratory and from images retrieved from the Rhoton Collection. Interactive visualization and magnification allowed multiple perspectives for an enhanced experience in VR. The quick response code offered a convenient method for importing anatomic models into the real world for rehearsal and for comparing other anatomic preparations side by side.

CONCLUSION

This proof-of-concept study validated the use of machine learning to render 3D reconstructions from 2-dimensional microsurgical images through depth estimation. This spatial information can be used to develop convenient, realistic, and immersive anatomy image models.

Virtual neurosurgery anatomy laboratory: A collaborative and remote education experience in the metaverse

Background:

Advances in computer sciences, including novel 3-dimensional rendering techniques, have enabled the creation of cloud-based virtual reality (VR) interfaces, making real-time peer-to-peer interaction possible even from remote locations. This study addresses the potential use of this technology for microsurgery anatomy education.

Methods:

Digital specimens were created using multiple photogrammetry techniques and imported into a virtual simulated neuroanatomy dissection laboratory. A VR educational program using a multiuser virtual anatomy laboratory experience was developed. Internal validation was performed by five multinational neurosurgery visiting scholars testing and assessing the digital VR models. For external validation, 20 neurosurgery residents tested and assessed the same models and virtual space.

Results:

Each participant responded to 14 statements assessing the virtual models, categorized under realism (n = 3), usefulness (n = 2), practicality (n = 3), enjoyment (n = 3), and recommendation (n = 3). Most responses expressed agreement or strong agreement with the assessment statements (internal validation, 94% [66/70] total responses; external validation, 91.4% [256/280] total responses). Notably, most participants strongly agreed that this system should be part of neurosurgery residency training and that virtual cadaver courses through this platform could be effective for education.

Conclusion:

Cloud-based VR interfaces are a novel resource for neurosurgery education. Interactive and remote collaboration between instructors and trainees is possible in virtual environments using volumetric models created with photogrammetry. We believe that this technology could be part of a hybrid anatomy curriculum for neurosurgery education. More studies are needed to assess the educational value of this type of innovative educational resource.

Toward "bigger" data for neurosurgical anatomical research: a single centralized quantitative neurosurgical anatomy platform

Quantitative neurosurgical anatomy research aims to produce surgically applicable knowledge for improving operative decision-making using measurements from anatomical dissection and tools such as stereotaxis. Although such studies attempt to answer similar research questions, there is little standardization between them, offering minimal comparability. Modern technology has been incorporated into the research methodology, but many scientific principles are lacking, and results are not broadly applicable or suitable for evaluating big-data trends. Advances in information technology and the concept of big data permit more accessible and robust means of producing valuable, standardized, reliable research. A technology project, "Inchin," is presented to address these needs for neurosurgical anatomy research. This study applies the concept of big data to neurosurgical anatomy research, specifically in quantifying surgical metrics. A remote-hosted web application was developed for computing standard neurosurgical metrics and storing measurement data. An online portal (Inchin) was developed to produce a database to facilitate and promote neurosurgical anatomical research, applying optimal scientific methodology and big-data principles to this recent and evolving field of research. Individual data sets are not insignificant, but a collective of data sets present advantages. Large data sets allow confidence in data trends that are usually obscured in smaller numbers of samples. Inchin, a single centralized software platform, can act as a global database of results of neurosurgical anatomy studies. A calculation tool ensuring standardized peer-reviewed methodology, Inchin is applied to the analysis of neurosurgical metrics and may promote efficient study collaboration within and among neurosurgical laboratories.