We Tabulated and Organized American Board of Neurological Surgeons Primary Exam Keywords (2015-2023) so You Don’t Have to

Background Passing the American Board of Neurological Surgeons (ABNS) Primary Exam is required for residents in training. Both the program directors and residents are given keywords of the exam afterward in the hope to help program directors determine their relative strengths and weakness. We have organized and tabulated these keywords for neurosurgery residents’ benefit. Methodology We collected and analyzed ABNS Primary Exam keywords (2015-2023) in each of the exam’s main categories for trends and recurrences. We examined the overall passing rates among first-time credit test takers. The frequency of each subcategory was calculated as a percentage within its corresponding category. Recurrent keywords were grouped together with their corresponding years and categorized as once, twice, or thrice and greater occurrences; the last category was considered to be high-yield keywords. Results The number of questions in Neurosciences and Neurology has decreased over the years while Neurosurgery and Critical Care questions have increased. Similarly, there are fewer keyword repeats in Neurosciences and Neurology. The most repeated keywords are in Neuroimaging. The most common keywords are presented and listed along with the years of occurrences. Overall, the passing rate among first-time credit test takers is over 90%. Conclusions Neurosurgery residents can consider the common keywords as a guide in preparation for the ABNS Primary Exam.


Introduction
The American Board of Neurological Surgery (ABNS) Primary Exam is administered during residency to test residents' knowledge, and passing it along with the successful competition of residency are requirements toward board eligibility. The test consists of eight main categories for a total of 375 questions while some questions are not graded [1]. Every year, ABNS forwards test results along with graded test question keywords to program directors and residents. Program directors receive the complete list of keywords while residents receive keywords on missed questions. The goal is to help program directors determine the strengths and weaknesses of their program. There is very little written or published about these keywords. Similarly, the American Board of Surgery In-Training Exam (ABSITE) also distributes keywords to residents and program directors for their annual exam; however, the keywords in the ABSITE are much more general and less specific than those found in the ABNS [2]. We have tabulated and organized these keywords according to their occurrences to indicate high-yield contents in the hope to help residents study for the exam.
can be calculated. Each set of keywords also contained percentages of correct among credit candidates and self-assessment test takers. Program directors receive the complete list of keywords while residents receive keywords on missed questions. We analyzed both sets of keywords.
We first calculated the total number of questions graded in each exam from 2015 to 2023 and looked for trends over the years. The keywords, already divided into eight categories, were then entered into a spreadsheet along with the corresponding year. In Neurosciences, we did not include the sub-subcategory listed by ABNS to simplify the list and to be consistent with other categories. Keywords are further subcategorized according to the ABNS content categories outline published in 2016 [1]. Repeated keywords were grouped together and highlighted when occurrences were three or greater. We took liberties to concise and group keywords leaving pertinent and specific information pertinent to the keywords intact. In Neuroimaging, we also made assignments that made the most sense as not all keywords included the type of imaging studies, which is the basis of ABNS categorization. For example, the authors assigned "Hydrocephalus, intraventricular hemorrhage, macrocephaly, Aqueductal stenosis" under Ultrasonography instead of CT or MRI.
We also calculated the frequency of its subcategories to determine the most tested areas in each category. Percentages of keyword occurrences were then calculated and divided into single-year occurrences, twice and thrice or more. Occurrences of three times or more were considered high yield and grouped together.

Results
The number of questions in the eight categories tested each year is listed on the ABNS website: Neuroanatomy

Neurosciences
Neurosciences, sometimes labeled neurobiology, is divided among microstructures, functional systems, and neurophysiology. We did not include the sub-subcategory listed by the ABNS to simplify the list and to be consistent with other categories. Approximately 18.1% of keywords are tested only once in this category, 23.8% twice, and 58.1% thrice or more during this time period. Table 3 shows the details for high-yield keywords and occurrences. There are overlaps with other categories found in keywords such as cerebral ischemia, diffusion-weighted imaging, and MR imaging. The most highly tested topics in Neurosciences

Neuropathology
Residents are frequently asked to identify structures or name disorders based on histopathological slides/micrographs/photos in Neuropathology. Approximately 11.6% of keywords are tested only once in this category, 11.2% twice, and 77.2% thrice or more during this time period. Table 4 shows the details for high-yield keywords and occurrences. The most highly tested topics in Neuropathology include the following keywords: von Hippel-Lindau disease, hemangioblastoma, and stromal cells.

Core competencies
The Core Competencies category is the smallest section in the Primary Exam, only slotted for seven questions out of 750 each year. It follows Accreditation Council for Graduate Medical Education's (ACGME) Milestones and ABNS added patient safety and ethics. Most of the questions can be found under the subcategory of Practice-Based Learning and Improvement.

Discussion
According to the ABNS, the distributed annual Primary Exam Keywords are to help program directors determine the "strength and weakness of their program." Our residents usually start taking the Primary Exam as PGY2s, and most of them pass it on their first try. Because most of our residents take the Primary Exam for credit and pass them as PGY4s, they usually take the Primary Exam three times during residency; rare, occasional, and exceptional residents have passed them on their second try. ABNS Primary Exam has a relatively high passing rate (>90%) among first-time credit test takers when compared to other subspecialties [3][4][5]. Not much has been published about the ABNS Primary Exam except for its relationship with the United States Medical Licensing Exam (USMLE) [6,7]. In view of our background, we created a database using the keywords from 2015 to 2023 as a template for our didactics. The database has evolved into our informal knowledge-based curriculum. According to ACGME program requirements for neurosurgery updated in July 2022, the curriculum "must contain a set of program aims consistent with the Sponsoring Institution's mission, the needs of the community it serves, and the desired distinctive capabilities of its graduates." Under medical knowledge, "residents must demonstrate competence in their knowledge of neurosurgical emergencies; treating neurosurgical conditions: cerebrovascular disorders, functional neurosurgery, neurocritical care, neuro-oncology, pain, pediatric neurological surgery, peripheral nerve disorders, spinal disorders and trauma. Different medical practice models and delivery systems and how to best utilize them to care for an individual patient; and, study design and statistical methods. All residents tracking towards ABNS certification must pass the ABNS primary examination before completing the program" [8].
The lists of keywords are quite extensive and comprehensive including both basic and clinical neurosciences. Even though we listed frequently tested and what we consider high-yield keywords, there are a significant number of keywords tested once or twice during 2005-2023 that should be considered as well. It should also be noted that each set of keywords contains percentages of correct among credit candidates and self-assessment test takers which we did not take into account in our study. The ABNS does not instruct individual programs on how to approach or use these keywords. We have expanded our keywords database by inserting comments on the spreadsheet itself from searches using Google Search or ChatGPT. The more precise or specific the keywords, the better the result in terms of information. For instances where images are needed, we linked the keywords to specific URLs. Our residents are encouraged to self-study and add content to the database. There are no specific trends in looking at the keywords and occurrences from 2015 to 2023. It is not uncommon to see a keyword tested for three consecutive years, take a hiatus, and then resurface a few years later. It is also very common to see a certain keyword tested several times in the same year in the same category or in other categories. There are also certain keywords tested every year. Most of the highest yielded keywords are fairly practical in the day-to-day practice of neurosurgery. Most of the keywords tested are often repeated more than three times during this period of time (58.1-82.2%), with the lowest repeat rate in Neurosciences and Neurology and the highest in Neuroradiology.
There are many ways to approach the Primary Exam as it is quite individualized. Most residents use commercially available review books and sample tests while others may take courses sponsored by the Congress of Neurological Surgeons such as Self-assessment in Neurological Surgery (SANS) which has evolved over the years [9][10][11]. Compared to neurosurgery, general surgery has many more options in terms of online resources. One example is the concept of Question Bank which has shown mixed results over the years [12,13]. Not many resources and references are found to be dedicated to the board exam keywords and such may be due to their inherent limitations. For example, there is no way to predict the exact exam questions and answers based on published keywords. Keywords can also be misleading and interpreted differently depending on the individual. Grouping of the keywords may also be subjective, and we analyzed the most recent ABNS Primary Exams keywords, i.e., 2015-2023, and not their entirety. Keywords for next year's exam may be very different from what we presented. Because the overall pass rate for the Primary Exams is high at over 90%, keywords themselves may add little or no value to most test takers.

Conclusions
We have organized, grouped, and tabulated keywords distributed by the ABNS for Primary Exams administered from 2015 to 2023. Throughout the years, many keywords are repeated which may reflect the emphasis of ABNS on certain areas in neurosurgery for residents to be focused on. Neurosurgery residency program directors and residents can consider the compiled list as a reference and guide.

Additional Information Disclosures
Human subjects: All authors have confirmed that this study did not involve human participants or tissue. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue.

Conflicts of interest:
In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work.