AANS Neurosurgeon | Volume 28, Number 4, 2019


The Future of Neurosurgical Education Part 2: Neurosurgical Residency

Print Friendly, PDF & Email

General Flow of Training

Organized neurosurgery is well ahead of most other surgical disciplines with respect to training issues. The American Association of Neurological Surgeons (AANS), American Board of Neurological Surgery (ABNS), Congress of Neurological Surgeons (CNS), ACGME Residency Review Committee (RRC) and the Society of Neurological Surgeons (SNS) have worked closely to keep neurosurgery together as a specialty, while recognizing that no neurosurgeon practices all aspects of neurosurgery. There have been many spirited discussions among neurosurgeons who have the most experience and interest in resident education. No consensus has been reached, so what follows is my predictions.

I believe that the forces driving us to sub-specialization will only increase in the future. To keep neurosurgery together as a vibrant, growing specialty, we must assure that our residents obtain excellent core neurosurgical training as well as fellowship-level training during or after the seven years of a neurosurgical residency. I suspect that in 10 years many neurosurgery residents will follow the general pattern of the training program described in Figure 1.

The resident starts neurosurgical training by learning to care for neurosurgical patients before and after surgery. This is accomplished by a six-month rotation on the neurocritical care service, followed by six months on the neurosurgery service. At the end of this year of training, the resident has:

  • Gained an understanding of the scientific basis of neurosurgical disease;
  • Learned to manage neurosurgical patients perioperatively; and
  • Has accrued six months of neurocritical care training that can be applied to completing a CAST-accredited fellowship in neurocritical care.

Post graduate year (PGY) 2 residents have rotations with increasing levels of surgical and non-surgical patient care responsibilities in all neurosurgery subspecialty areas, experience in affiliated specialties like neuroradiology and time for academic pursuits, such as research project planning and manuscript preparation. By the end of PGY 4, the resident should have reached Level 3 in all milestones and be trained in core neurosurgery. The resident now has one year of chief residency and two years of elective time for subspecialty training. In this example (Figure 1), the resident has decided to focus her practice in neurocritical care and endovascular neurosurgery. The PGY 5 year starts with six months of neurocritical care, which completes the requirements for completing a CAST-accredited neurocritical care fellowship. This fellowship, like any good fellowship experience, must include a research component. During the last six months of PGY 5, the resident accrues additional neuro-endovascular cases, working toward the 200 neuro-endovascular procedures that need to be completed before starting a CAST-accredited neuro-endovascular fellowship.

During PGY 6, the resident assumes the responsibilities of chief resident and continues to improve her medical knowledge base, patient care skills and operative abilities. By the end of the chief resident year, the resident is well trained in core neurosurgery, has completed a neurocritical care fellowship, has passed the primary ABNS examination and is prepared to enter PGY 7 of training. 

Figure 1. Neurosurgery Training: Core, Neurocritical Care and Endovascular Neurosurgery

Post-Graduate Year

 Resident Assignments


Neurocritical Care



During PGY 2-PGY 4, the resident has rotations with increasing levels of surgical and non-surgical patient care responsibilities in all neurosurgery subspecialty areas, experience in affiliated specialties like neuroradiology and time for academic pursuits such as research project planning and manuscript preparation. Cognitive skills in areas such as clinical trial design, biostatistics, evidence-based medicine, ethics, medical economics and quality improvement are taught throughout the residency. 



Core Training Accomplished

By the end of PGY 4, the resident has achieved Level 3 in all milestones and is trained in core neurosurgery. One year of chief residency and two years of elective time remain for training. In this example, the additional training will prepare for a focused practice in neurocritical care and endovascular neurosurgery.


Six months of neurocritical care

(must include research)

Six months of endovascular neurosurgery


Chief Resident


One year of endovascular neurosurgery fellowship

(must include research)

PGY 7 is for independent study, which in this case will be an enfolded neuro-endovascular fellowship, which must include a research component. At graduation, this resident will have had excellent training in core neurosurgery, completed fellowship training in neurocritical care and endovascular neurosurgery and will have had a research experience in both subspecialty areas.

Training in areas such as clinical trial design, biostatistics, evidence-based medicine, ethics, professionalism, medical economics, patient safety and quality improvement is provided throughout the residency. Knowledge in these areas will be essential to all neurosurgical practices.

Special Considerations

Duty Hours

Neurosurgery is a demanding specialty, but we do much more than perform procedures. We care for our patients in the clinic, the emergency room, the operating room, the recovery room, the intensive care unit and on the hospital wards. We are specialists in the care of patients with neurological disease, not technicians who have mastered a motor skill. We have always taken care of our patients whenever they need us, for as long as they need us. This is a founding principle of our specialty that we must not abandon. 

Mastery of the knowledge and skills required to manage the long list of neurosurgical disorders requires many years of commitment and intensive experience. Neurosurgical learning episodes — from initial contact with the patients, through their evaluation, surgical treatment and immediate postoperative care — encompass many hours. To obtain the greatest educational value from these learning experiences and to offer the safest care for neurosurgical patients, a resident must be present throughout this sequence of events. When these experiences cross arbitrary shift boundaries our residents are forced to decide between doing what is best for their patients and their education or following the rules that tell them they must punch the clock.

Maximizing patient safety and resident education requires attention to supervision and fatigue management – not designated shifts. Supervision will vary according to the level of training, with junior residents requiring more immediate supervision than senior residents who are assuming a greater degree of autonomy and responsibility for patient care. The last two years of resident training should serve as a transition to practice, during which residents develop the time management, clinical experience and operative skills to become an independent neurosurgical practitioner. The future of neurosurgery training must be allowed to incorporate a more flexible schedule, balancing these conflicting demands. Only flexibility will help residents internalize the importance of the continuity of care, take personal responsibility for their patients, avoid the moral dilemmas of the shift work system and enhance professionalism. 


We have always expected each neurosurgeon in training to have a meaningful research experience. The value of such an experience is difficult to overestimate. Every neurosurgeon should be able to form a hypothesis, test it, analyze the results and prepare for presentation to the neurosurgical community. However, this does not mean that every neurosurgeon must spend a given number of months in a laboratory. For the resident who wants a career that includes a significant component of laboratory research, an opportunity to learn those skills should be available. The traditional emphasis on “spending two years in the laboratory” as the only means of having a valuable resident research experience should be reconsidered. More neurosurgeons will be able to have a meaningful research experience, during and after residency, by learning clinical research skills and how to collaborate closely with PhD laboratory scientists. These options will allow more neurosurgeons to meld a busy clinical practice with meaningful research, thus continuing our tradition of innovation and progress.    

Educational Technology

Advancing technology has clearly changed the operative practice of neurosurgery and will likely radically change other aspects of patient care and resident education. We are all familiar with how the immediate access to digital information has changed the way we procure information. Ever-expanding digital capabilities and their increasing integration into our daily practice will change how we train our residents and care for our patients in profound ways. I will restrict this discussion to two areas that I think will have an ever-increasing role in neurosurgical education and practice – simulation and artificial intelligence.


The ability to practice a procedure many times without putting patients at risk will be a significant advancement for neurosurgical education. Currently, in some areas, such as endovascular neurosurgery, the ability to simulate procedures is quite advanced, while other applications have lagged behind.4 This technology will continue to develop and allow us to use realistic simulation training for more and more neurosurgical procedures. It is essential that simulation becomes a cornerstone of training to allow our future residents to develop surgical skills without risk to patients. I can envision a process where future residents must reach a predetermined level of technical accomplishment in simulated surgery before refining their training in real surgical procedures.

Artificial Intelligence and Predictive Analytics

We employ informal predictive analytics every day by taking the data we have available to us, considering the management options and mentally predicting the outcome of each option. I suspect that this kind of informal predictive analytics will be augmented by more formal predictive analytics in the future.2 As neurosurgeons, we are faced with an ever-increasing barrage of data to be analyzed when making clinical decisions. The rapid growth in computer processing power and the increased ability to use this computational power has generated a great deal of interest in machine learning algorithms to improve our capabilities for diagnosis, prognosis and patient management. Machine learning algorithms, such as artificial neural networks, can employ diverse types of medical data as inputs and integrate them into categorized outputs. Formal predictive analytics uses available data, statistical algorithms and machine learning techniques to identify the likelihood of future outcomes. This will enhance our ability to assess what will happen to an individual patient under varying management options. Our residents will likely incorporate this technology seamlessly into their management decisions, much like prior generations embraced technology such as computed tomography, magnetic resonance imaging and image guided procedures.


The purpose of neurosurgical certification is to reassure our patients that the neurosurgeon they are trusting with their lives is safe and competent in the practice of neurosurgery. When the ABNS was created in 1940, the best way to determine this was to have candidates examined by practicing neurosurgeons. I doubt that this is the best process now and for the future. 

To reassure the public, we need to evaluate each neurosurgeon’s knowledge base, technical skills, judgment and professionalism. If a certain body of knowledge is necessary to practice neurosurgery safely, formal testing is a reliable method to determine if the candidate has this knowledge. However, after a neurosurgeon completes training, those who award certification do not directly observe his or her technical skills, judgment and professionalism. Currently, the ABNS reviews consecutive cases, submitted by the candidates, in preparation for the oral examination. Evaluation of this practice data, if accurate, is the clearest indication of the candidates’ technical skills, judgment and professionalism. The ABNS has recently upgraded its data collection system to include imaging, which will further assist in this critical practice assessment.

Without the constraints of history, were we to develop a system today to assure the public of the  competency and safety of a neurosurgeon, I think the system would:

  • Award ABNS certification when a neurosurgeon completes an ACGME-accredited program, passes the ABNS Primary Examination and receives a letter from their program director stating that he or she is now competent to practice independently;
  • Have the ABNS diplomate begin his or her maintenance of certification (MOC) process immediately; and
  • Base MOC on an analysis of consecutive cases submitted each year.

For instance, if the newly-certified neurosurgeon began practicing on July 1, 2018, on January 1, 2020 he or she would be asked by the ABNS to submit 25 consecutive cases with imaging and three-month follow-up data, starting on a randomly chosen date between October 1, 2018, through September 30, 2019. This process would repeat each year. Case logs would be reviewed by a computer algorithm looking for indicators that would trigger an audit and a review by present and former ABNS directors. In addition, 10 percent of the submitted case logs would also be chosen for a random audit. If the reviewers voiced concerns, additional data could be sought and appropriate remedies applied. 

Such a system would avoid the expense associated with travel, coverage, time away from practice and other logistical issues associated with preparing for and taking the oral examination. It would be based on real world patient selection and outcomes. Certification of the future will maximize the power of computer analysis along with dedicated human endeavor for real-time assessment of every neurosurgical practice.


Since its founding 100 years ago, neurosurgery has always been a vibrant specialty because we have welcomed and led change while adhering to our founding principles.3 I believe we are well positioned to continue this trajectory and that we will recognize and embrace necessary changes in how we train our residents. 



1. Grillo, H.C. (1999). To impart this art: The development of graduate surgical education in the United States. Surgery. 125(1), 1-14.

2. Harbaugh, R. E. (2018). Editorial. Artificial neural networks for neurosurgical diagnosis, prognosis, and management. Neurosurgical Focus.

3. Harbaugh, R. E. (2015). The 2015 AANS Presidential Address: Neurosurgery’s founding principles. Journal of Neurosurgery, 1351-1357.

4. Kirkman MA, Ahmed M, Albert AF, Wilson MH, Nandi D, Sevdalis N. The use of simulation in neurosurgical education and training a systematic review. J Neurosurg 121: 228-246, 2014.

Leave a Reply

Be the first to reply using the above form.