The Evolution of Pain Medicine as a Subspecialty
As knowledge expands and the need for detailed skills arises, specialization ensues. This is a natural progression, and it has become impossible for any physician to become an expert in every field. There has long been discomfort with specialization despite unflagging progression in this direction. The urge to both specialize and remain unspecialized dates back to the earliest recorded history in medicine. The first specializations were between barber-surgeons and internists, and a rivalry of sorts remains to this day. Writing about Ambrose Paré, the 16th century physician who elevated the role of barber-surgeons to that of other physicians, the present-day surgeon and historian Sherwin Nuland reflected on the ongoing distinction between internist and surgeon :
Surgery is an exercise in the use of the intellect. Heckling internists, with tongues barely in check, would prefer that surgical specialists be viewed merely as dexterous craftsman who carry out the routing errands assigned to them by their more cerebrally endowed medical overseers. I attribute this teasing raillery to a kind of good-natured fraternal envy, not so much of our celebrity status, but rather of the visibility of the cures we surgeons achieve and the particular personal gratification we have while doing it.
In the United States, anesthesiology has progressed toward further specialization, first with the establishment of critical care, then pain management (now pain medicine), and more recently pediatric anesthesiology and cardiothoracic anesthesiology. The addition of pain medicine as a subspecialty of anesthesiology is just one recent example of the growth of medical specialties. With specialization comes a conscious effort to focus practice so that one becomes intricately familiar with a more limited realm. The obvious result is loss of the skills and knowledge needed to practice in the broader parent specialty. In pain medicine, many now view this as a full-time vocation. The scientific meetings and journals that keep pain medicine specialists up-to-date have little overlap with those that are designed to serve anesthesiologists practicing in the operating room. The only common thread between the technical skills needed in the pain clinic and those required for anesthesiology in the operating room is expertise in neural blockade. The pain medicine practitioner must acquire a vastly different skill set from those practicing anesthesiology, including expanding their skills as diagnosticians.
Much has been written about the origins of pain medicine as a distinct discipline, and anesthesiologists have played a primary role since the start. It really started with the introduction of effective general anesthetics in the mid-19th century, when surgical pain could be separated from surgery. Almost 100 years later, the late John Bonica, an anesthesiologist and recognized father of the specialty that we now call pain medicine, developed his career by promoting multidisciplinary pain care and formal training of specialists. From his life’s work we now have extensive ongoing efforts to recognize and treat pain effectively, to train subspecialists, and to conduct basic and clinical research to further our understanding of pain and its treatment. The International Association for the Study of Pain, founded in 1974, its U.S. chapter the American Pain Society, and the journal Pain are legacies left by Dr. Bonica for our patients.
Accredited fellowship training in pain medicine is a relatively recent development. Before 1992, training was frequently obtained in academic anesthesiology departments, including those of Bonica, Bridenbaugh, Carron, Haugen, Moore, Raj, Winnie, and others, and subsequently in programs run by their trainees. These unaccredited programs advanced the specialty, widened interest in pain medicine as a career, and propagated pain care in smaller and smaller communities across the country. Outside the United States, this type of informal training remains the rule for those seeking expertise in pain medicine. In the United States, the American Board of Anesthesiology (ABA) developed interest in certifying pain medicine specialists following their training. Through the leadership of Dr. William Owens in his roles in both the ABA and the Accreditation Council on Graduate Medical Education (ACGME) and through his representations of the subspecialty to the American Board of Medical Specialties, formal training programs were accredited and physicians were certified. Drs. Stephen Abram and John Rowlingson were both key members of the group that assisted Dr. Owens in moving the new subspecialty forward.
The first programs were accredited by the ACGME in 1992. The number of ACGME-accredited programs and trainees in accredited programs has grown steadily over the past decade, and there are now just more than 100 training programs that turn out about 300 new pain specialists each year. Working in parallel with ACGME, the ABA developed a subspecialty certification examination in pain medicine, first named the “Certificate of Added Qualifications in Pain Management” and now titled “Subspecialty Certification in Pain Medicine.” The first examination was given in 1993. The number of candidates taking the examination has grown steadily since the initial examination.
Dr. Bonica’s original push to develop multidisciplinary pain care recently evolved into collaboration between four specialties that agreed to a single and unified set of program requirements for all ACGME-accredited pain fellowships, regardless of the sponsoring specialty. The ACGME Residency Review Committees for Anesthesiology, Neurology, Physical Medicine, and Rehabilitation and Psychiatry agreed on these requirements in late 2005, and the ACGME board approved their implementation for 2007. These requirements have standardized pain fellowship training programs. After introduction of the new training requirements in 2007, a number of programs closed because of unwillingness to adopt a multidisciplinary approach, and thus only the more comprehensive programs were left to continue the training of physician pain specialists ( Fig. 7.1 ). Programs have begun to produce more comprehensive and multidisciplinary focused physicians from a wider range of primary disciplines ( Figs. 7.2 and 7.3 ). Other groups are also encouraging a more comprehensive approach to pain care, with the linked American Academy of Pain Medicine and the American Board of Pain Medicine likewise devoting energy to a multidisciplinary approach. There remain a number of experienced pain specialists who believe that eventually the ACGME-accredited fellowships will be extended to 2 years to cover an expanding knowledge base. Equally important in evolution of the discipline is the creation of academic physicians within the fellowships who undertake research programs to add new knowledge to guide clinical practice in this area of medicine.
Pain and its consequences draw on resources from all medical disciplines. Dr. Bonica’s experiences during World War II suggested that each medical specialist had unique expertise to bring to patients suffering pain—hence his consistent and effective promotion of a multidisciplinary process for pain care. Also thanks largely to Dr. Bonica, anesthesiology has led the development of formal training programs. Indeed, the majority of currently accredited programs reside within academic anesthesiology departments, and most program directors are anesthesiologists. Specialists from other disciplines have also focused their clinical and research efforts on pain. The most obvious example is neurology, from which the majority of clinical treatment and research on headache has arisen. The field of physical medicine and rehabilitation has also had a focus and expertise on functional restoration, and physiatrists lead many chronic pain rehabilitation programs. Moreover, psychiatrists and psychologists have of course been closely involved when pain, depression, and substance abuse overlap. During the last decade, specialists from these other disciplines have been seeking subspecialty training in pain medicine with increasing regularity.
The range of practitioners declaring themselves pain medicine specialists is extraordinary, from clinics that provide largely or solely cognitive-behavioral approaches to chronic pain through functional restoration programs all the way to the type of clinic that offers nothing more than injections of various sorts. “Interventional pain medicine” is a phrase that has been coined for techniques that involve minimally invasive treatments and minor surgery as part of their application, including neural blockade and implantable analgesic devices. Despite the paucity of scientific evidence to guide pain practitioners, particularly evidence to support the use of many interventional modalities, many techniques appear to have efficacy based on limited observational data and have been adopted into widespread use. As practitioners, we are left to choose among the treatment modalities available, often with only anecdotal and personal experience to guide us in treating a group of desperate patients with intractable pain who are willing to accept almost any treatment, even though it remains unproven. There is no single practice pattern that pain specialists can point to as being the correct way to treat patients with chronic pain. Training programs vary widely in the scope of what they train practitioners to do. The best pain medicine practitioners strike a reasonable balance between interventional and noninterventional management. This practice pattern is sustainable, and those adopting a balanced style of practice will be able to adapt to the evolving scientific evidence that appears in support of pain treatment, regardless of the type of treatment. A balance between treatment modalities also allows practitioners to switch from one mode to another or to incorporate multiple treatment approaches simultaneously. Use of these interventional modalities is just a small part of the armamentarium of a skilled pain practitioner.
Training and Credentialing in Interventional Pain Medicine
In our rapidly changing world of modern health care, new technologies are appearing at a dizzying rate. Many of these new treatments require physicians to acquire detailed new knowledge and technical skills. The introduction of new techniques typically extends from centers in the public or private sector, where the ideas are conceived and tested in a limited realm among innovators. From there, anecdote can often take over, and many techniques in pain medicine have blossomed into widespread use with nothing more than word of mouth to propagate their use. The use of pulsed radiofrequency treatment of pain is one such example in which clinical application has preceded detailed clinical testing.
In the United States and Europe, industry often leads innovation by testing and initiating the introduction of new devices. When the innovation appears to have merit in limited trials, many devices are introduced to the market with approval through the Food and Drug Administration’s 510K “substantially similar device” process with little or no data regarding efficacy. Once on the market, the means by which practitioners decide to adopt new technologies, the speed of progression of these new techniques, and—of great importance—the means by which practitioners gain enough expertise to introduce new techniques into their own practice are all highly variable and seemingly without any rational or consistent approach.
Interventional pain medicine is evolving as a distinct discipline that requires detailed new knowledge and expertise. Familiarity with radiographic anatomy for performing image-guided injections and the minor surgical skills needed to implant devices such as spinal cord stimulators and drug delivery systems are just a few of the techniques that practitioners must master. As we set out to introduce new interventional techniques into our own pain practices, we must be sure that we have been properly trained to perform these techniques in a manner that ensures safety and success.
Adequate exposure to these newer treatment alternatives during the fellowship training period is necessary to ensure appropriate application and optimize patient outcomes. Although we do not have scientific data that define the average minimum level of experience that will be necessary to achieve competence, especially for complex procedures associated with significant risk, logic dictates that that trainees should be exposed to a minimum number of these procedures during a fellowship. The ACGME has established requirements for the average minimum number of epidural, spinal, and peripheral nerve blocks necessary for the accreditation of anesthesiology residency programs. Other medical subspecialties also require a minimum number of specified procedures to achieve and maintain competence: subspecialty training in gastroenterology has a requirement for performing a minimum of 100 esophagogastroduodenoscopy and 100 colonoscopy procedures with polyp removal during formal training, and subspecialty training in cardiovascular disease requires 100 cardiac catheterization procedures to demonstrate minimum proficiency. Indeed, the ACGME’s Residency Review Committee for Anesthesiology has accepted revised Program Requirements for Pain Medicine Training Programs that specify the minimum exposure of trainees to various procedures, including image-guided injection techniques for the cervical and lumbar spine; sympathetic blockade; neurolytic block, including radiofrequency treatment of pain; spinal cord stimulation; and placement of permanent spinal drug delivery systems. For techniques that are now widely accepted as a core element of pain practice, we must ensure that our trainees gain enough experience to conduct these procedures independently. One key element of the ACGME deliberations about unified pain training is to acknowledge that not all pain fellows will have experience in the wide variety of interventional techniques. Rather, it is hoped that these fellows will gain an understanding of all available options for patients with pain and yet demonstrate and have competence documented in only techniques for which formal training is made available during fellowship training.
It is difficult to define the techniques that are core for a pain practitioner, but it does seem that detailed knowledge of the radiographic anatomy of the spine and the minor surgical expertise required to implant spinal cord stimulators and permanent spinal drug delivery systems are among the skills that most practicing pain physicians would expect a new graduate from a pain fellowship program to have. New techniques are appearing at a staggering rate, and we cannot rely on pain fellowship programs to provide all the technical training that is needed. Stronger standards for minimum training following fellowship programs are also urgently needed. Some pain practitioners believe that too many of their colleagues find it perfectly acceptable to attend a brief weekend course and then introduce a highly technical new treatment into practice without additional study, training, or oversight. Practitioners themselves must take the lead in obtaining adequate training before proceeding with any new and unfamiliar technique. A weekend workshop is just a start, often a good start—the best workshops will give practitioners a detailed understanding of anatomy, pathophysiology of disease related to use of the new technique, patient selection, conduct of the procedure, outcomes, and avoidance, management, and recognition of complications. Box 7.1 is a suggested method for practitioners to introduce a new technique into clinical practice.
