Albert L. Rhoton Jr., MD: His Philosophy and Education of Neurosurgeons

Recent advances in Otology: Current landscape and future direction

Hearing is an essential sensation, and its deterioration leads to a significant decrease in the quality of life. Thus, great efforts have been made by otologists to preserve and recover hearing. Our knowledge regarding the field of otology has progressed with advances in technology, and otologists have sought to develop novel approaches in the field of otologic surgery to achieve higher hearing recovery or preservation rates. This requires knowledge regarding the anatomy of the temporal bone and the physiology of hearing. Basic research in the field of otology has progressed with advances in molecular biology and genetics. This review summarizes the current views and recent advances in the field of otology and otologic surgery, especially from the viewpoint of young Japanese clinician-scientists, and presents the perspectives and future directions for several topics in the field of otology. This review will aid next-generation researchers in understanding the recent advances and future challenges in the field of otology.

A primer to vascular anatomy of the brain: an overview on anterior compartment

PURPOSE

Knowledge of neurovascular anatomy is vital for neurosurgeons, neurologists, neuro-radiologists and anatomy students, amongst others, to fully comprehend the brain's anatomy with utmost depth. This paper aims to enhance the foundational knowledge of novice physicians in this area.

METHOD

A comprehensive literature review was carried out by searching the PubMed and Google Scholar databases using primary keywords related to brain vasculature, without date restrictions. The identified literature was meticulously examined and scrutinized. In the process of screening pertinent papers, further articles and book chapters were obtained through analysis and additional assessing of the reference lists. Additionally, four formalin-fixed, color latex-injected cadaveric specimens preserved in 70% ethanol solution were dissected under surgical microscope (Leica Microsystems Inc, 1700 Leider Ln, Buffalo Grove, IL 60089 USA). Using microneurosurgical as well as standard instruments, and a high-speed surgical drill (Stryker Instruments 1941 Stryker Way Portage, MI 49002 USA). Ulterior anatomical dissection was documented in microscopic images.

RESULTS

Encephalic circulation functions as a complex network of intertwined vessels. The Internal Carotid Arteries (ICAs) and the Vertebral Arteries (VAs), form the anterior and posterior arterial circulations, respectively. This work provides a detailed exploration of the neurovascular anatomy of the anterior circulation and its key structures, such as the Anterior Cerebral Artery (ACA) and the Middle Cerebral Artery (MCA). Embryology is also briefly covered, offering insights into the early development of the vascular structures of the central nervous system. Cerebral venous system was detailed, highlighting the major veins and tributaries involved in the drainage of blood from the intracranial compartment, with a focus on the role of the Internal Jugular Veins (IJVs) as the primary, although not exclusive, deoxygenated blood outflow pathway.

CONCLUSION

This work serves as initial guide, providing essential knowledge on neurovascular anatomy, hoping to reduce the initial impact when tackling the subject, albeit the intricate vasculature of the brain will necessitate further efforts to be conquered, that being crucial for neurosurgical and neurology related practice and clinical decision-making.

Anatomy of the craniocervical junction - A review

An in-depth understanding of the anatomy of the craniocervical junction (CCJ) is indispensable in skull base neurosurgery. In this paper, we discuss the osteology of the occipital bone, the atlas (C1) and axis (C2), the ligaments and the muscle anatomy of the CCJ region and their relationships with the vertebral artery. We will also discuss the trajectory of the vertebral artery and review the anatomy of the jugular foramen and lower cranial nerves (IX to XII). The most important surgical approaches to the CCJ, including the far lateral approach, the anterolateral approach of Bernard George and the endoscopic endonasal approach, will be discussed to review the surgical anatomy.

A Scoping Review of Professionalism in Neurosurgery

BACKGROUND AND OBJECTIVES

The Accreditation Council for Graduate Medical Education's Milestones provides a foundation for professionalism in residency training. Specific professionalism concepts from neurosurgery could augment and expand milestones for the specialty. We reviewed the current literature and identified professionalism concepts within the context of neurosurgical practice and training.

METHODS

We used a scoping review methodology to search PubMed/MEDLINE and Scopus and identify English-language articles with the search terms "professionalism" and "neurosurgery." We excluded articles that were not in English, not relevant to professionalism within neurosurgery, or could not be accessed. Non-peer-reviewed and qualitative publications, such as commentaries, were included in the review.

RESULTS

A total of 193 articles were included in the review. We identified 6 professionalism themes among these results: professional identity (n = 53), burnout and wellness (n = 51), professional development (n = 34), ethics and conflicts of interest (n = 27), diversity and gender (n = 19), and misconduct (n = 9).

CONCLUSION

These 6 concepts illustrate concerns that neurosurgeons have concerning professionalism. Diversity and gender, professional identity, and misconduct are not specifically addressed in the Accreditation Council for Graduate Medical Education's Milestones. This review could be used to aid the development of organizational policy statements on professionalism.

Petrous internal carotid artery aneurysm: A cause of chronic otitis

BACKGROUND

Aneurysm of the petrous segment of the internal carotid artery (pICA) is a rare pathology presenting with extracranial and especially oto-rhinological symptoms that can be misleading and delay diagnosis.

METHODS

We report the case of a giant pICA aneurysm compressing the Eustachian tube (ET), presenting with hearing loss due to chronic serous otitis. A PRISMA review of the literature was performed to find similar cases. In addition, relevant anatomical sources were screened.

RESULTS

Five reports about 7 cases of middle-ear effusion caused by pICA aneurysm compressing the ET were identified. Median age at diagnosis was 18.5 years. After endovascular treatment, overall outcome was favorable, with no mortality, although outcome was sometimes impaired by neurological comorbidities and unclear prognosis of hearing-loss recovery.

DISCUSSION

These reports, though rare, offer relevant insights into the poorly known regional anatomy of the pICA, in the borderland between neurosurgery and ENT. Within the petrous bone, the osseous separation between the ET and the pICA is narrow, when not dehiscent. This leads to a risk of any pathological process in either the pICA or the ET impinging on the other.

CONCLUSION

Giant pICA aneurysm is a rare cause of hearing loss, due to compression of the ET, leading to chronic serous otitis. This co-dependency between pICA and ET should be kept in mind, as it underlines the necessity of multidisciplinary management and could facilitate earlier diagnosis and therapeutic management when facing atypical clinical situations.

Use of 3-Dimensional Modeling and Augmented/Virtual Reality Applications in Microsurgical Neuroanatomy Training

BACKGROUND

Understanding the microsurgical neuroanatomy of the brain is challenging yet crucial for safe and effective surgery. Training on human cadavers provides an opportunity to practice approaches and learn about the brain's complex organization from a surgical view. Innovations in visual technology, such as virtual reality (VR) and augmented reality (AR), have immensely added a new dimension to neuroanatomy education. In this regard, a 3-dimensional (3D) model and AR/VR application may facilitate the understanding of the microsurgical neuroanatomy of the brain and improve spatial recognition during neurosurgical procedures by generating a better comprehension of interrelated neuroanatomic structures.

OBJECTIVE

To investigate the results of 3D volumetric modeling and AR/VR applications in showing the brain's complex organization during fiber dissection.

METHODS

Fiber dissection was applied to the specimen, and the 3D model was created with a new photogrammetry method. After photogrammetry, the 3D model was edited using 3D editing programs and viewed in AR. The 3D model was also viewed in VR using a head-mounted display device.

RESULTS

The 3D model was viewed in internet-based sites and AR/VR platforms with high resolution. The fibers could be panned, rotated, and moved freely on different planes and viewed from different angles on AR and VR platforms.

CONCLUSION

This study demonstrated that fiber dissections can be transformed and viewed digitally on AR/VR platforms. These models can be considered a powerful teaching tool for improving the surgical spatial recognition of interrelated neuroanatomic structures. Neurosurgeons worldwide can easily avail of these models on digital platforms.

International Neurosurgery: The Role for Collaboration

The global death toll from lack of access to basic surgical care is three times as much as for tuberculosis, HIV and malaria combined. Patients dying of curable neurosurgical conditions solely because of inadequacy or absence of neurosurgical infrastructure is an issue deserving immediate attention and action. Global neurosurgery is an important step forward in this regard, under which different models of collaboration between HICs and LMICs aim to increase both the number of neurosurgeons as well the quality of neurosurgical care available in these countries through arranging surgical camps, providing neurosurgical training and education, and restructuring the health system in these countries in order to create an environment conducive to the provision of the highest form of neurosurgical care. Despite the many challenges faced by LMICs in furthering neurosurgery programs such as poor resource allocation, brain drain, turbulent socioeconomic conditions, limited training facilities, and population explosion, data now being reported from LMICs the world over, exemplifies the immense positive impact that collaborations have had over the last few decades in improving neurosurgical capacity and infrastructure. So far, conventional methods of collaboration (i.e. neurosurgical missions to LMICs and training of neurosurgeons in HICs) have been effective in progressively bringing about the desired change in LMICs. However, these methods have been limited by a finite funding, pushing the global neurosurgical community to look for alternatives such as online curricula, task shifting and sharing, and long distance mentor-mentee relationships. In this review, we aim to provide an update on the current state of neurosurgical collaborations and identify the barriers in the way of collaborations and what alternative models of collaboration might be used to overcome them..

Impact of international research fellows in neurosurgery: results from a single academic center

OBJECTIVE

International research fellows have been historically involved in academic neurosurgery in the United States (US). To date, the contribution of international research fellows has been underreported. Herein, the authors aimed to quantify the academic output of international research fellows in the Department of Neurosurgery at The Johns Hopkins University School of Medicine.

METHODS

Research fellows with Doctor of Medicine (MD), Doctor of Philosophy (PhD), or MD/PhD degrees from a non-US institution who worked in the Hopkins Department of Neurosurgery for at least 6 months over the past decade (2010-2020) were included in this study. Publications produced during fellowship, number of citations, and journal impact factors (IFs) were analyzed using ANOVA. A survey was sent to collect information on personal background, demographics, and academic activities.

RESULTS

Sixty-four international research fellows were included, with 42 (65.6%) having MD degrees, 17 (26.6%) having PhD degrees, and 5 (7.8%) having MD/PhD degrees. During an average 27.9 months of fellowship, 460 publications were produced in 136 unique journals, with 8628 citations and a cumulative journal IF of 1665.73. There was no significant difference in total number of publications, first-author publications, and total citations per person among the different degree holders. Persons holding MD/PhDs had a higher number of citations per publication per person (p = 0.027), whereas those with MDs had higher total IFs per person (p = 0.048). Among the 43 (67.2%) survey responders, 34 (79.1%) had nonimmigrant visas at the start of the fellowship, 16 (37.2%) were self-paid or funded by their country of origin, and 35 (81.4%) had mentored at least one US medical student, nonmedical graduate student, or undergraduate student.

CONCLUSIONS

International research fellows at the authors' institution have contributed significantly to academic neurosurgery. Although they have faced major challenges like maintaining nonimmigrant visas, negotiating cultural/language differences, and managing self-sustainability, their scientific productivity has been substantial. Additionally, the majority of fellows have provided reciprocal mentorship to US students.

Volume of Surgical Freedom: The Most Applicable Anatomical Measurement for Surgical Assessment and 3-Dimensional Modeling

Surgical freedom is the most important metric at the disposal of the surgeon. The volume of surgical freedom (VSF) is a new methodology that produces an optimal qualitative and quantitative representation of an access corridor and provides the surgeon with an anatomical, spatially accurate, and clinically applicable metric. In this study, illustrative dissection examples were completed using two of the most common surgical approaches, the pterional craniotomy and the supraorbital craniotomy. The VSF methodology models the surgical corridor as a cone with an irregular base. The measurement data are fitted to the cone model, and from these fitted data, the volume of the cone is calculated as a volumetric measurement of the surgical corridor. A normalized VSF compensates for inaccurate measurements that may occur as a result of dependence on probe length during data acquisition and provides a fixed reference metric that is applicable across studies. The VSF compensates for multiple inaccuracies in the practical and mathematical methods currently used for quantitative assessment, thereby enabling the production of 3-dimensional models of the surgical corridor. The VSF is therefore an improved standard for assessment of surgical freedom.

The most recommended neuroanatomy resources for neurosurgeons: an international survey

Background:

Neuroanatomy is the core basis for neurosurgical excellence. The quantity of accessible neuroanatomy resources has witnessed exponential growth in recent years. Accumulating a list of popular sources and getting them ranked by neurosurgeons was the motivation behind this investigation.

Methods:

A list of neuroanatomy resources was compiled using Google search wherein multiple sets of variable combinations of keywords were used. A three-section, eleven-item questionnaire was designed by two neurosurgeons and revised by a third independent reviewer. Neurosurgeons from different parts of the world were invited to participate. The participants were asked to rank the neuroanatomy textbook and non-book online source that they would recommend to neurosurgeons and the features that make a textbook appealing to them.

Results:

A total of 250 neurosurgeons at different levels of training responded to our questionnaire. Overall, “Rhoton’s Cranial Anatomy and Surgical Approach: Albert L. Rhoton Jr., Doctor of Medicine” was the most commonly chosen textbook that the neurosurgeons would use to revise neuroanatomy (86.0%; n = 215), recommend for residents (80.8%; n = 202) and recommend for certified surgeons (Continuing Medical Education (59.8%; n = 150), where applicable. “Illustrations” was rated as the most important neuroanatomy textbook quality by 53% (n = 134). “Rhoton collection” was the most popular online source (65.7%; n = 164.25). Chi-square tests showed no association between years of experience and the textbooks neurosurgeons recommended.

Conclusion:

Based on our study Rhoton’s book and his online collection are the leading neuroanatomy resources, recommended by neurosurgeons for neurosurgeons worldwide. The other selected resources can be implemented as a complementary part of a comprehensive neuroanatomy teaching curriculum. Knowing the relevance of these assets from a neurosurgeon’s perspective is valuable in directing future educational plan updates and recommendations.

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

The incorporation of perspective into art and science revolutionized the study of the brain. Beginning in about 1504, Leonardo da Vinci began to model the ventricles of the brain in three dimensions. A few years later, Andreus Vesalius illustrated radically novel brain dissections. Thomas Willis' work, Cerebri Anatome (1664), illustrated by Christopher Wren, remarkably showed the brain undersurface. Later, in the early 1800s, Charles Bell's accurate images of neural structures changed surgery. In the 1960s, Albert L. Rhoton Jr. (1932-2016) began to earn his place among the preeminent neuroanatomists by focusing his lens on microanatomy to harness a knowledge of microneurosurgery, master microneurologic anatomy, and use it to improve the care of his patients. Although his biography and works are well known, no analysis has been conducted to identify the progression, impact, and trends in the totality of his publications, and no study has assessed his work in a historical context compared with the contributions of other celebrated anatomists. We analyzed 414 of 508 works authored by Rhoton; these studies were analyzed according to subjects discussed, including anatomic region, surgical approaches, subjects covered, anatomic methods used, forms of multimedia, and subspecialty. Rhoton taught detailed neuroanatomy from a surgical perspective using meticulous techniques that evolved as the technical demands of neurosurgery advanced, inspiring students and contemporaries. His work aligns him with renowned figures in neuroanatomy, arguably establishing him historically as the most influential anatomist of the neurosurgical era.

Minimally Invasive Approaches to Anterior Skull Base Meningiomas

Objective Anterior skull base meningiomas include olfactory groove, planum sphenoidale, and tuberculum sellae lesions. Traditionally, standard craniotomy approaches have been used to access meningiomas in these locations. More recently, minimally invasive techniques including supraorbital and endonasal endoscopic approaches have gained favor; however there are limited published series comparing the use of these two techniques for these meningiomas. Using our patent database, we identified patients who underwent these two approaches, and conducted a retrospective chart review to compare outcomes between these two techniques.

Methods A total of 32 patients who underwent minimally invasive approaches were identified: 20 supraorbital and 11 endoscopic endonasal. Radiographic images, presenting complaints and outcomes, were analyzed retrospectively. The safety of each approach was evaluated.

Results The mean extent of resection through a supraorbital approach was significantly greater than that of the endoscopic endonasal approach, 88.1 vs. 57.9%, respectively (p = 0.016). Overall, preoperative visual acuity and anopsia deficits were more frequent in the endonasal group that persisted postoperatively (visual acuity: p = 0.004; anopsia: p = 0.011). No major complications including cerebrospinal fluid (CSF) leaks or wound-related complications were identified in the supraorbital craniotomy group, while the endonasal group had two CSF leaks requiring lumbar drain placement. Length of stay was shorter in the supraorbital group (3.4 vs. 6.1 days, p < 0.001).

Conclusion Anterior skull base meningiomas can be successfully managed by both supraorbital and endoscopic endonasal approaches. Both approaches provide excellent direct access to tumor in carefully selected patients and are safe and efficient, but patient factors and symptoms should dictate the approach selected.

Ergonomics-based Positioning of the Operating Handle of Surgical Microscopes

Handling surgical microscopes with one hand requires force, especially when gripping the operating handle (OH) to swing the optic axis toward the surgeon and when moving it laterally or medially. These physical issues may be attributable to the non-ergonomic handling of the OH. To optimize the ease of OH handling, we applied ergonomic criteria to the positioning of the OH, i.e. holding the OH at as little ulnar deviation as possible and at abduction to strengthen the grip and ease arm rotation. Of eight male surgeons holding the OH of a mechanically counterbalanced surgical microscope, the OPMI Neuro/NC4 (Carl Zeiss AG), in ergonomics-based positions, six experienced reduced fatigue in the upper extremity. All reported that their hold on the microscope was firm when it unexpectedly became unbalanced. Ergonomics-based OH positioning, i.e. placing the involved muscles in the optimal length-tension relationship, may generate sufficient force for moving the microscope efficiently and reduce arm fatigue.

Foundations of Advanced Neuroanatomy: Technical Guidelines for Specimen Preparation, Dissection, and 3D-Photodocumentation in a Surgical Anatomy Laboratory

Objective  This study was aimed to provide a key update to the seminal works of Prof. Albert L. Rhoton Jr., MD, with particular attention to previously unpublished insights from the oral tradition of his fellows, recent technological advances including endoscopy, and high-dynamic range (HDR) photodocumentation, and, local improvements in technique, we have developed to optimize efficient neuroanatomic study. Methods  Two formaldehyde-fixed cadaveric heads were injected with colored latex to demonstrate step-by-step specimen preparation for microscopic or endoscopic dissection. One formaldehyde-fixed brain was utilized to demonstrate optimal three-dimensional (3D) photodocumentation techniques. Results  Key steps of specimen preparation include vessel cannulation and securing, serial tap water flushing, specimen drainage, vessel injection with optimized and color-augmented latex material, and storage in 70% ethanol. Optimizations for photodocumentation included the incorporation of dry black drop cloth and covering materials, an imaging-oriented approach to specimen positioning and illumination, and single-camera stereoscopic capture techniques, emphasizing the three-exposure-times-per-eye approach to generating images for HDR postprocessing. Recommended tools, materials, and technical nuances were emphasized throughout. Relative advantages and limitations of major 3D projection systems were comparatively assessed, with sensitivity to audience size and purpose specific recommendations. Conclusion  We describe the first consolidated step-by-step approach to advanced neuroanatomy, including specimen preparation, dissection, and 3D photodocumentation, supplemented by previously unpublished insights from the Rhoton fellowship experience and lessons learned in our laboratories in the past years such that Prof. Rhoton's model can be realized, reproduced, and expanded upon in surgical neuroanatomy laboratories worldwide.