Training Paradigms for Vascular Trauma

Introduction

The issue of surgical training—whether vascular or general—faces a number of significant current and future challenges. Firstly, the advent of vascular surgical residencies in the United States and Great Britain has widened the gap between vascular surgery and general surgery as specialties, and it has specifically limited the exposure of vascular surgeons to major trauma and constrained the general surgeons experience with regard to the fundamentals of diagnosis and management of perfusion abnormalities, techniques of vascular imaging, exposure, and surgical or endovascular intervention. Secondly, the introduction of work-hour restrictions in the United States, the United Kingdom, and the European Union has led to dramatically decreased opportunities for professional contact with patients and clinical material for all trainees. The full impact of these work-hour directives is only now being assessed. However, a recent study by the Royal College of Surgeons of England suggests that the quality of patient care has sharply declined because of the lack of continuity of care, and it further suggests that operative exposure is insufficient to ensure competency in an adequate range of procedures for independent practice. Thirdly, the development of ever–increasingly complex procedures, including endovascular techniques, has strained the ability of surgical residency or fellowship programs to endow competence and proficiency in all the required areas of practice. Fourthly, the extensive adoption of minimally invasive techniques, both endovascular and laparoscopic, has decreased the opportunities for trainees to develop the open surgical skills needed to treat traumatic injuries. Fifthly, there is increasing scrutiny of the quality of health care, brought about by a number of high-profile cases involving medical errors, such as the Bristol Enquiry in the United Kingdom and the Institute of Medicine’s “To err is human” report in the United States. This increasing scrutiny has led to closer supervision and less independence during surgical training, which in turn can impede the development of confident and decisive surgical trainees.

As a result of these challenges, current training paradigms for both general and vascular surgery are inadequate for expert management of traumatic vascular injury, and they each provide a different foundation on which to build with additional training. This has led some individuals who are particularly interested in vascular injury management to seek additional training or experience in both trauma management and vascular disease management. This dual training has resulted in some true experts, but it is inefficient and impractical to meet the demand. Surgical educators have also responded by developing short courses involving both didactic and simulation training to meet the demand for additional training in the management of vascular injuries.

Graduate Medical Education

Training in surgery has traditionally followed an apprenticeship model, with the trainee undergoing supervised exposure to decision-making and technical skills under the tutelage of a “craft” master. Historically, the acquisition of vascular techniques—whether by master or apprentice—has followed a model whereby the development of new skills occurs via adaption and remolding of previously learned skill sets. However, with the increased adoption of multimodal imaging in the diagnosis and minimally invasive techniques in the management of general surgical and vascular disease, the opportunity to transfer previously learned skills to these new realms of practice is concordantly lower. Image acquisition and interpretation at the point of care and new endovascular therapies pose substantial technical challenges, similar to those experienced by practitioners of laparoscopic and minimally invasive surgery (MIS). These include reduced tactile sensation, a two-dimensional (2-D) (rather than a three-dimensional [3-D]) perspective, and the need to overcome proprioceptive and visual issues. Additional data sources and new decision-making algorithms and treatment opportunities often require new training models and educational curricula—applicable to both established specialists and surgical trainees—while paying heed to new restrictions in duty hours. The relentless and inevitable drive to subspecialize has concurrently required practitioners to master new techniques at the cost of narrowing clinical focus and constraining the surgical armamentarium required for trauma injury management. With these issues in mind, it is timely to consider new and emerging ways of delivering training to surgeons expected to manage patients with vascular trauma.

The current trend in surgical training within the United States is toward a structured, competency-based curriculum with objective and ongoing documentation of proficiency within residency training and then going into independent practice. Toward this end, national organizations including the American College of Surgeons (ACS), the American Board of Surgery (ABS), the Residency Review Committee–Surgery (RRC-S) of the Accreditation Council for Graduate Medical Education (ACGME), the American Surgical Association, the Association for Program Directors in Surgery, and the Association for Surgical Education have established a national consortium called the Surgical Council on Resident Education (SCORE) to reform general surgical residency education. The SCORE has developed a national curriculum. The SCORE portal provides a modular curriculum that combines learning objectives, discussion questions, text resources and videos, and self-assessment quizzes in a single online format. Program directors can track a trainee’s progress by self-study through the curriculum over the course of a residency. The Association for Program Directors in Vascular Surgery has nearly completed a similar curriculum specific to vascular surgery (VSCORE). The aim is to ensure alignment of the core content of the training program, the core competencies expected as learning outcomes, and the assessment practices. This will confirm that—no matter what program or tract a resident completes—measurable and acceptable levels of competence are achieved in all required areas. Unfortunately, experiential learning through case volume has suffered significantly since the late 1990s, and the decline in case volume threatens the effectiveness of our current training paradigms.

Graduate Medical Education/Residency Training in General Surgery

The increasing specialization of vascular surgeons and their training, especially with the advent of stand-alone GME programs in vascular surgery, has diluted the available training opportunities for general surgery residents with the majority of open vascular cases being done by vascular surgeons and vascular residents/fellows. In a study of 22 general surgery residencies, the opening of a vascular surgery fellowships was associated with a 17% decline in vascular surgery cases for general surgery residents. Similarly, the opening of a 0-5 integrated vascular surgery residency was associated with a 20% decline in vascular case numbers for general surgery residents at the University of South Florida.

Overall, and in spite of the fact that many still consider vascular surgery to be an integral part of general surgery training, trainees are getting less experience in this area. Surgical residents in the United States are required to self-report the number and nature of the cases they perform during their training to the ACGME. Although the quality of these case logs is limited by the nature of self-reporting, they remain the best quantitative data available on the operative experience of residents. Examining ACGME case logs from 1999 to 2017, Cortez et al. found a 10% decrease in vascular case volume reported by general surgery residents. A more detailed analysis of ACGME case data by Drake et al. found that case volume declined by 50% in the chief resident year, arguably the most important year to consolidate and firmly establish the knowledge, skills, and abilities (KSAs) of surgical practice. Open arterial cases are clearly those most necessary to develop competence in treating vascular trauma, and those have also declined at an alarming 38% over the first two decades of the 21st century. The average number of vascular cases for trauma that were reported by graduating residents to the ACGME as being performed over the entire residency program in general surgery decreased from 5.2 in 1999–2000 to 1.5 in 2008–09 to 1.1 in 2017–18 ( Table 4.1 ). It is important to bear in mind that these data reflect average experience, and as such there are significant numbers of trainees who have no experience caring for patients with major vascular trauma. Furthermore, the reported experience of all upper extremity vascular cases by graduating general surgery residents averaged 2.0 cases per trainee in 2017–18. These reports reveal extremely limited experience in the management of vascular injury and very limited experience in open vascular surgery in specific anatomic regions. This is particularly concerning to the military community because of experience from operations in Iraq and Afghanistan where the brachial artery was a frequently injured structure. The decline in case volume is multifactorial, and many of the relevant changes in training have occurred nearly simultaneously. In addition to the transition to laparoscopic, endoscopic, and endovascular techniques, an increasing trend toward conservative management of solid organ injury has contributed to significantly fewer opportunities for trainees to undertake open surgical procedures.

Table 4.1

The Average Number of Selected Cases over the Duration of Training

Data collated from https://www.acgme.org/Data-Collection-Systems/Case-Logs-Statistical-Reports .

	1999–2000	2002–03	2005–06	2008–09	2011–12	2014–15	2017–18
Major vascular cases for trauma—General Surgery Residents	5.2	4.9	4.6	4.7	1.5	1.2	1.1
Major vascular cases for trauma—Vascular Surgery 5+2 Fellows	7.2	8.1	10.7	12.5	10.7	12.2	12.0
Major vascular cases for trauma—Vascular Surgery 0+5 Residents	NA	NA	NA	NA	NA	11.0	10.1

Note: This data was reported by graduating chief residents and was supplied as part of the case log submitted to the American Board of Surgery from 1999 to 2018.

Numbers represent the mean for each procedure; and, if missing (NA), that procedure was not reported during that particular year.

The advent of duty hour restrictions has also had a deleterious effect. Although overall case numbers have remained stable for general surgery residents, the breadth and variety of operative experience has declined. Increases in laparoscopic and alimentary tract procedures have offset significant declines in trauma and vascular cases. The 80-hour workweek has also increased the variability of residents’ experience. Whereas average case numbers remain the same, the difference in case volume between residents has increased suggesting that the quality of graduating residents may be more variable. The hope that many of the KSAs needed to treat vascular injuries in trauma patients can be gained by elective operative experience is unfounded. The concurrent decrease in total vascular cases, open arterial cases, and trauma cases after duty-hour restrictions calls in to questions the preparedness of general surgery trainees to treat trauma.

Based on the data presented, it is clear that general surgery residents in the United States have a suboptimal experience with the surgical management of vascular trauma. In Canada, vascular surgery has been removed from the Canadian general surgery training objectives. In a survey of 29 Canadian surgical residents, 90% reported an intention to perform vascular procedures after training despite the same cohort self-reporting of inadequate training in 10 of the 13 procedures surveyed. Unsurprisingly, the authors of this study concluded that current trainees may lack the skills and abilities to deal with vascular emergencies.

In spite of the growing prevalence of specialist-trained vascular surgeons, there are still many areas in the world (developed and underdeveloped) where the primary surgeon may not be a vascular surgical specialist and where opportunities to practice a vascular skill set are infrequent. Ensuring that a fully trained vascular surgical specialist is available for each and every trauma case is not practical in many hospitals, and is certainly unfeasible in the austere domains of military and humanitarian surgical practice. Thus, the need to train competent practitioners who can handle vascular trauma is universal. The development of vascular damage control techniques such as vascular shunting, which require a less refined set of KSAs, offers a potential solution wherein vascular injuries can be temporarily managed by general surgeons with shunting followed by evacuation or transport to a vascular specialist.

Graduate Medical Education/Residency Training in Vascular Surgery

Within the United Kingdom, the vascular curriculum is set by the Intercollegiate Surgical Curriculum Programme (ISCP). The ISCP benefits from the input of specialty advisory committees (SACs) representing each of the 10 surgical specialties. It is also informed by and collaborates with the Surgical Royal Colleges of Great Britain and Ireland and other professional bodies, including the Local Education and Training Boards (established in 2013) and the General Medical Council (GMC). In 2012, vascular surgery became established as a fully-fledged surgical specialty and left the aegis of the General Surgery SAC, with a dedicated training pathway leading to specialist certification, separate from that of general surgery.

In the United States, vascular surgery has been (and is still considered by many to be) an integral part of general surgery training and practice. Before 1960, no specific training programs existed in vascular surgery, and vascular surgery was practiced by general and cardiothoracic surgeons. The first vascular surgery–specific training programs, including the vascular surgery fellowship at Walter Reed Army Medical Center, were, in essence, apprenticeships directed by some of the pioneers of vascular surgery. Training opportunities were advanced considerably when the membership of the Society for Vascular Surgery (SVS) voted in 1979 to develop accredited vascular training programs. Initially, 17 programs were approved, rising to 52 programs by 1982. In 1982, the first 14 ABS Certificates of Special Qualifications in General Vascular Surgery were issued, each earned after successful completion of a written examination. In the 1990s, leading vascular surgeons pushed for recognition of vascular surgery as a specialty distinct from general surgery, based on the underlying premise that patient outcomes were improved when care was provided by a specialist in vascular surgery rather than a general surgeon who occasionally performed vascular operations. Subsequently, vascular surgery became a distinct specialty of surgery on March 17, 2005, when (with approval of the American Board of Medical Specialties) the ABS agreed to offer a Primary Certificate in Vascular Surgery. In October 2005, training program requirements for this certificate were approved, and the traditional requirement for 5 years of training and certification in general surgery was eliminated. Effective July 1, 2006, the ABS converted its certificate in vascular surgery from a subspecialty certificate to a specialty (primary) certificate. These landmark changes heralded the development of new training paradigms. Two pathways have evolved: the traditional Independent (5+2) 2-year vascular surgery fellowships following a 5-year general surgery program and Integrated (0+5) vascular surgery residency immediately following medical school. 5+2 graduates are eligible for dual board certification by the ABS in general and vascular surgery while 0+5 graduates are only eligible for vascular surgery certification.

Vascular trauma is increasingly funneled toward specialist trauma or vascular surgeons, but opportunities to gain experience in vascular trauma are still limited. The numbers of major vascular repairs for trauma that were reported to the ABS by vascular surgery fellows—though significantly greater than that reported by graduates of general surgery residencies—are small, with the average number of cases reported as 7.2 in 1999–2000 and 12.0 in 2017–18 (see Table 4.1 ). Furthermore, more than 60% of these procedures were peripheral in nature with surgical experience of vascular trauma in the thorax and neck being particularly low, averaging less than one case in each area per resident.

Integrated and Independent GME programs seem to provide a similar volume of vascular trauma cases to trainees although long-term data is not available yet (see Table 4.1 ). In addition, overall case numbers in most categories of vascular surgery are similar between graduates of integrated and independent programs. Nonetheless, there may be important differences in the experiences of graduates from these different types of programs. Graduates of independent programs have a more concentrated operative experience performing more open and major cases during their final years of training. The advantages of completing general surgery residency may also be significant. Between 2012 and 2014, graduating general surgery residents performed more than twice as many open abdominal procedures on average than integrated vascular surgery residents. Integrated vascular surgery residents do pursue open surgical procedures during their general surgery rotations, but these cases are most often minor, nonabdominal procedures.

Endovascular surgery has had a mixed effect on case volume in vascular training programs. Open peripheral case volume has remained stable, whereas endovascular case volume has exploded. Open aortic case volume, however, has decreased dramatically. Of the approximately 45,000 abdominal aortic aneurysms (AAA) repaired in the United States each year, only 15% are repaired with open techniques. The effect of this on vascular surgical trainees’ ability to care for vascular trauma is unknown.

After training, experience with vascular trauma remains limited for many surgeons. US vascular surgeons seeking recertification have reported the following data: in 2003, only 46% of surgeons reported having undertaken any trauma cases in the previous 12 months; in 2009, this proportion had diminished to 23%. In both cohorts, the accumulated annual experience amounted to an average of four procedures. Though it is difficult to judge proficiency and competence by volume data alone, it is certain that the experience of trainees is anything but uniform, and the limited experience raises the question whether these specialists have the requisite skill set to ensure the best outcomes when called to care for patients with vascular injuries. Likewise, only a small minority of vascular specialists report that management of vascular trauma comprises part of their clinical practice.

It is clear that the experiential approach cannot be relied on as a means of endowing surgical trainees with the required KSAs to expertly manage vascular injuries. As such, there is a critical need to improve the way training is conducted in order to secure the best care for patients with vascular trauma. The remainder of this chapter explores the evolving challenges faced by those tasked with training the surgeon of the future and discusses current and near-term modalities that are likely to improve the uniformity of training in the management of vascular trauma.

Ways Forward for Vascular Trauma Training

As previous chapters demonstrate, effective trauma management presents specific challenges, with the requirement for rapid, systematic assessment and decision making to prevent patient deterioration. However, every injury pattern is unique with some factors coming to light only in the operative phase of management, and it is not always possible to rehearse and preplan all aspects of surgical management. This mandates that any training algorithm must include core principles that can be adapted and can be flexibly deployed to deal with the individual situation at hand. Training must be set at two distinct levels: (1) the KSAs required by nonvascular specialists to prevent deterioration, to surgically stabilize the patient, and to set the conditions for further specialist intervention and (2) the advanced specialist skills necessary to deal with complex injuries, postoperative issues, complications, and guide long-term management. Clinical educators generally consider surgical training to have the following two separate components: (1) a “hands-on” practical learning of technical skills and (2) the acquisition of knowledge and cognitive skills. Cognitive orientation centers around the ability to organize relevant information and to construct a strategy that enables the best use of the relevant skill. In other words, cognitive orientation is needed in order to make appropriate decisions. Didactic lectures, textual material, and, more recently, case-based training have been used for transfer of information and cognitive skills. Technical and cognitive components of clinical training are inseparable; they inform each other. Since Dewey’s 1938 pioneering work, experiential learning has been recognized as an important part of how adults acquire new knowledge and skills (i.e., “learning by doing” is a particularly effective method for advancing cognitive and technical skills). Modern theory emphasizes the problem-centered approach and the need to understand the contextual orientation of the adult learner. Effective and systematic training is a byproduct of the quality of the curriculum that is developed to enhance that training.

As yet, the ideal curriculum for training in vascular trauma has not been delineated and will likely be specific to national situations as well as the needs of and learning styles of individual learners. However, the ideal curricula will clarify goals and objectives in unambiguous terms, driven by consensus of expert opinion. The obvious goal is to produce competent and proficient practitioners who can appropriately diagnose and apply cognitive, technical, and teamwork skills to the management of patients presenting with vascular trauma, aided by a thorough understanding of anatomy and current open-surgical and endovascular techniques. The remainder of this chapter will focus on the wide variety of tools that are currently employed to train in vascular surgery in general and vascular trauma in particular.

Vascular Trauma Training Tools

The tools currently available to teach the management of vascular trauma include the following:

1.
Clinical case material—care of patients
2.
Didactic lectures
3.
Textbook and digital media
4.
Case-based discussion
5.
Team-based training
6.
Animal-model–based training
7.
Human-cadaver–based training
8.
Simulation-based training
- a.
  Synthetic models—low and high fidelity
- b.
  Virtual reality

The ideal vascular trauma curricula will incorporate several of these tools ordered to the goals and objectives of the educational program. Clinical case material has long been the mainstay of vascular trauma training, but, as discussed previously, can no longer be counted on to provide sufficient experience. Didactic lectures, textbook and digital media, and case-based discussion represent the bulk of traditional methods to convey information, but have limited effectiveness if not focused by and incorporated within a meaningful curriculum. Likewise, simulation training using animal models and human cadavers have proved extremely useful in the training of surgeons, but their use must be based on a thorough needs assessment and on a good understanding of their inherent limitations.

The use of animals for training has several advantages and a number of distinct limitations. Animals provide excellent approximations of human physiology, necessitating careful and appropriate choices and executions of surgical maneuvers in order to avoid excess hemorrhage and death. Animal tissues require standard operating equipment and supplies; they bleed when cut; and they exhibit damage if not handled, dissected, and sutured carefully. However, maintenance of an animal laboratory is expensive and logistically intensive, requiring veterinary support, animal care facilities, sterile operating rooms (OR), and humane and sanitary disposal of the animals. Animal laboratories are rightly subject to stringent care standards in order to ensure animal welfare. The use of animals is a highly visible and emotionally charged issue decried by very active and vocal animal rights groups. Another key disadvantage of animal models concerns differences in anatomy such that they are usually inadequate for teaching anatomic vascular exposures. The availability of live animal models for training purposes is highly variable across the world and is prohibited in many areas. Though still available in the United States, the US Department of Defense (DoD) has directed that medical simulation and other alternative methods of training are to be utilized to the maximum extent practicable before the use of animals for the training of physicians and combat medics. The surgical community must therefore be proactive in searching for replacements to live-tissue training as this model is unlikely to be universally available in the future.

Cadaver-based training is particularly useful for teaching vascular exposures in humans, a skill essential to the effective treatment of vascular injuries. The availability and cost of cadavers is highly variable, as is the cultural acceptability of using cadaveric material around the world. For instance, the cost of obtaining cadavers for one such trauma course (the Advanced Surgical Skills for Exposure in Trauma [ASSET] course) is highly variable, ranging up to $8000, depending on the US state concerned. Even in areas where it is possible to obtain cadaveric material, the number of adequate specimens may not be sufficient to meet the need. Of interest is the low willingness of medical professionals to donate their own bodies for medical education. In a recent survey of medical professionals in India, only 22% of physicians stated that they were willing to donate their bodies for medical education (though only 7% had already registered to do so), but 68% expected the public to do the same.

Though cadavers give an excellent representation of human anatomy, they have some limitations. Most cadavers are elderly and deconditioned—translating the lessons learned on an 80-year-old woman with diminished muscle mass to a muscular 20-year-old male may be difficult. Cadaver tissue preserved in formalin has very different characteristics than tissue found in a fresh or fresh-frozen cadaver. Cadavers have no blood flow and do not bleed. Attempts have been made to improve the fidelity of cadaveric specimens by cannulating the vessels of very fresh cadavers and perfusing them with artificial blood in a pulsatile fashion. Initially developed for neurosurgical training, such perfused cadaver models have been modified as potential tools for training on trauma surgical procedures. Pulsatile flow can be obtained using a modified intraaortic balloon pump system and injuries created in the heart, lung, liver, and inferior vena cava, allowing for repair in a “bleeding human model.” Though this technique improves the fidelity of the cadaveric model, it requires significant preprocessing and equipment, as well as very fresh cadaveric material, making it impractical for widespread use and adoption.

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