Pa The folowing historical essay by Prof. J.D. Loeser was written largely from a North American perspective. The EFIC Comittee of Publications invites comments and short essays enhancing the European perspective. Please send such material to Prof. Marshall Devor at marshlu@vms.huji.ac.il , or by mail to the Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem 91904, Israel. The reader should also be aware ot the extensive historical archive on the subject of pain available at The John C. Liebeskind History of Pain Collection (UCLA History of pain Project)

http://www.library.ucla.edu/biomed/his/pain.htm

PAIN PAST, PRESENT AND FUTURE

John D. Loeser, M.D.
Departments of Neurological Surgery and Anesthesiology
University of Washington School of Medicine
Seattle, WA


Versions of this paper have been presented at the Canadian Pain Society Meeting in Banff, Alberta on May 12, 2000 and at the New England Pain Society Meeting in Woodstock, Vermont on February 4, 2000. It has been published in the Canadian Pain Society's Journal of Pain Research and Management and the IASP circular, "Clinical Notes" in January, 2001. It is presented here with the permission of IASP Press.

Correspondence to:
John D. Loeser, M.D.
Department of Neurological Surgery
University of Washington, Box 356470
Seattle, WA 98195
jdloeser@u.washington.edu
Tel: 206-543-3570
Fax: 206-543-8315

THE PAST AND THE PRESENT

An apology to all those whose native language is not English. My language limitations as well as my residence in the USA make it likely that significant developments in non-English-speaking countries have been omitted from this review. I would enjoy hearing from EFIC members about historically important European events in the development of pain management that I have overlooked.

WHERE WE WERE BEFORE 1960

Prior to 1960, there were neither pain specialists nor pain research. After World War II only one textbook had been written, the first edition of Bonica's "Management of Pain", which was published in 1953 (1). It was mainly the work product of one man. Behan had published a text in 1918, but it never enjoyed wide circulation and pain management did not develop from this publication (2). There were no journals devoted to pain, no dedicated research laboratories, no funding programs aimed at pain research nor training for clinicians. Some physiological research was carried out upon normal volunteers and very little on patients. What was labeled "pain" in most research was really nociception. A few men were ahead of their peers, Leriche, Noordenbos and Livingston stand out in my mind. I have been informed that a German anesthesiologist, Ernst von der Porten, in 1928, started a journal entitled "Der Schmerz", but it was quickly merged into an anesthesiology journal (3). Livingston actually had a pain laboratory and published a book about his clinical observations and speculations in 1943 (4). Beecher had pursued the placebo response, but this was not focused upon painful phenomena. Bonica described himself as self-taught in pain management, largely as the result of his military experiences. Major textbooks of medicine and surgery and other specialties, rarely even discussed the topic of pain management. Pain was described as a by-product of some disease state; the implication was that proper treatment of the disease would lead to pain relief. The sensory nervous system was envisioned as a passive set of wires that conducted impulses from the periphery to the brain.

WHAT HAPPENED 1960-1970

In 1960, Bonica became Chairman of Anesthesiology at the University of Washington and began his national and international campaign to put pain research and pain management into both basic sciences and clinical activities. This occurred at the time of the blossoming of academic medical centers and the rapid expansion of the National Institutes of Health, so that funding for research and training became abundant in the USA. Dedicated pain research programs were launched in many sites both in the USA and abroad. In 1965, the Melzack-Wall Gate Theory was published in Science (5). Its effect upon both clinical and research activities was profound. The nervous system was recognized to exert modulation upon sensory information, both at the primary synapse and in the brain. Parallel with the impact of the Gate Theory was the emergence of conceptualizing pain as, in part, a behavioral or learning-impacted phenomenon. This was the great contribution of Bill Fordyce, but many others developed this area of endeavor. The number of journal articles addressing pain began to increase, but medical textbooks were still oblivious to pain as a clinically important problem.

WHAT HAPPENED 1970-1980

Bonica convened the International Pain Congress in Issaquah, Washington in June, 1973. The pain movement was launched at that time, largely, but not exclusively through his efforts. The International Association for the Study of Pain derived from that meeting, as well as its journal, "Pain", its task forces, committees, and triennial Congresses. A major effort to found national chapters was also part of this organization. Other journals were started by those with special professional or regional issues. The biopsychosocial approach became an alternative to the biomedical concept of pain, and the desirability of multidisciplinary pain treatment became an integral part of the pain movement (6). It became widely recognized that modulation of afferent information was the rule, not the exception (7). Research on pain flourished, but there were few animal models for the chronic pains that plagued patients. The NIH began to recognize that pain research was within its mandate and should be encouraged. Training programs and CME (continuing medical education) programs became much more common. Research articles relevant to pain rapidly increased in number and quality; a few textbooks identified pain as an important clinical issue.

WHAT HAPPENED 1980-1990

Pain research exploded in this decade, in keeping with the expansion of all aspects of neuroscience research. Clinical training programs were established and standards for training and patient care promulgated. A rapid increase in books and scientific papers related to pain was noted. Several other textbooks of pain were published. Terminology was standardized and multicenter clinical trials became feasible. Palliative care became a specialty of its own, and, because of the rapidly expanding elderly population, was supported in many countries, although not nearly as well in the USA. Managed care and the rationing of health care became common topics for newspapers and politicians. It never was the care that was to be managed, but, instead, the costs of care. All of this started before there was very much outcomes data to compare alternative strategies, so we know that it was never a rational process. The citizens of some countries were happy to be able to travel to others or to buy into private health care when rationing became too oppressive. Many doctors fled from both rationing and managed care. Pain management was caught up in a much wider problem - the politicization of health care. Many new pain organizations, both of health care providers and patients, were launched. Far more articles about pain occurred in the lay press than ever before. Alternative health care strategies were widely utilized for pain management. Molecular biological approaches to the nociceptive process and central modulation of pain expanded our knowledge of the biological basis of pain.

WHAT HAPPENED 1990-2000

The molecular biology of pain thrived in this decade, providing astounding insights into the cellular and membrane basis of the transmission of nociceptive information. At the same time, powerful imaging techniques (fMRI and PET scanning) offered new methods of looking at brain function on a psychological and cognitive level. However, the idea was promulgated by basic scientists that their study of nociceptive mechanisms would lead to an adequate understanding of the genesis of pain. The study of the mechanisms of downstream modulation and cognitive and affective processes did not develop as rapidly, for methodological, conceptual and financial reasons. The biopsychosocial model found even more widespread acceptance as a better way to conceptualize clinical pain problems (8). The opiate wars moved from China to North America, where the debate over the proper use of narcotics for patients with chronic pain was based on little scientific information but much observer bias. We are still looking for a balance, and outcomes-based guidelines remain only a hope for the future. None-the-less, expanded utilization of opiates for both cancer and nonmalignant pain have brought great relief of suffering. Pain, suffering, pain behaviors, impairment and disability also became a hotly debated set of issues (9). The linkages between these phenomena are looser than many would like us to believe, and we are saddled with unworkable disability determination systems in most jurisdictions. Attempts to rationalize and make more equitable the social support networks offered to those who cannot or will not work have been met with resistance from those with vested interests in preserving the status quo. Many of the issues in this aspect of pain and its assessment involve intellectual disciplines that are too broad for one individual to adequately master. It is my belief that most of those engaged in the provision of health care and the administration and adjudication of issues related to pain and its related impairments and disabilities fail to adequately grasp the roles of affect, environment and anticipated consequences on patients (10).

 

BASIC SCIENCES

The neurosciences will continue to develop exponentially, led by the desire of pharmaceutical companies to find new drugs that will generate profits. Some of the areas that will be fruitfully developed include the peripheral mechanisms that translate tissue injury onto nociception, the targeting of membrane channels and receptors that are unique to the nociceptive system, and the changes within the nervous system that occur in neuropathic pain states. New modulators of the communications between and within nerve cells will be discovered. Much more difficult to undertake will be studies of the spinal cord and brain related to the modulation of sensory information, including pain. Imaging techniques will provide insights into brain-behavior relationships. Pain will be looked at as the product of a conscious mind and not just a passive response of the brain to external stimuli. Better models for many of the human pain states will be developed and exploited to develop new treatments based upon animal experimentation.

CLINICAL SCIENCES

The most important clinical step will be the development of clinical guidelines based upon outcomes research. The traditional guidelines by consensus will not suffice. Much of the pain movement's energy needs to be focused upon this area, for it will be the single most important development to keep pain management viable. In the interim, we need to move towards treatment by protocol so that outcomes can be compared in multicenter studies. Determination of meaningful outcomes will also be a battleground. It is clear that patient self-report of pain is important, but not adequate. Functional status, health care consumption and work status must also be assessed. We must be careful, however, to maintain enough flexibility in guidelines to cope with the fact that our ability to precisely diagnose the causes of pain states is limited. Different patients may need very different treatment strategies, even though they carry similar or even identical diagnoses. Indeed, different mechanisms for pain genesis probably exist within a single, clinical, diagnostic rubric. Expert judgement must accompany treatment guidelines. Nowhere is this more important than in the establishment of reasonable criteria for the use of opioids in the treatment of chronic pain.

Pain management is caught up in the global issue of how much health care a country wants to fund, and who will make the decisions as to what will be included in the list of funded treatments. If we do not align ourselves with those who will make these critical decisions, we may be left out of the funded health care providers club. This is part of the issue of proving our worth by demonstrating outcomes and creating a demand for our services by the patients. Of course, this takes us back to the issue of who is "us"? I would like to propose that pain management must mean more than just giving pills or doing procedures or providing biofeedback. These are technologies that are legitimately part of what we may want to offer our patients, but those who provide only such a service need to be looked at as specialists to be consulted when a need arises. They should not be in the position of managing the care of a patient with chronic pain. Put in another way, pain management means more than symptom control. It also means restoration of normal function.

PAIN AND DISABILITY ISSUES

The determination of impairment and disability due to pain is a major issue in many developed societies. The disability system was designed for overt injuries: damage to the body can be seen and measured, impairment assessed by physicians, and disability awarded based upon that impairment. The AMA (American Medical Association) rating system, which is the best-publicized guide for rating impairment, has never been validated and is completely arbitrary. Its section on pain is too opaque to be useful in determining impairment. Indeed, the Guide seems to deny the existence of impairment unless there is a loss of body part or function. We need a better conceptual basis for dealing with the social and economical aspects of the complaint of pain. We now have a plague of subtle injuries in which impairment cannot be measured. Medical education does not train one to rate such patients; this is a political problem, and we should stop asking physicians to do this job. This is a good example of the medicalization of modern life as Illich so aptly described over 20 years ago (11). The recognition that being on disability is a co-morbidity for most illnesses should lead to changes in the way physicians and politicians think about disability status. Those societies that provide health care for all of their citizens are far ahead of the United States in this area.

THINGS TO WORK FOR

How we snicker and guffaw about the leeches and purges used by our eighteenth and nineteenth century colleagues. Their patients usually paid their bills and said thank you, although Voltaire and Shaw certainly saw through them. What are you and I going to do to reduce the risks that the twenty-first century doctors will not scoff at our attempts to be useful? I think that the course is clear. We need to provide humane, caring health care based upon the best information we currently have available while constantly seeking to improve our knowledge base by properly conducted clinical trials. It is essential that we preserve the caring role, as that has been the single defining trait of physicians. It certainly has not been our technology that has kept the profession going since the dawn of recorded history. We need to fight for funding for comprehensive pain management, not just procedures to treat those who hurt. Pain management must be included in whatever type of health plan is organized by a country or an insurance agency. Treatment guidelines and algorithms need to be developed and based upon outcomes, costs and risks. There is certainly no single way to treat all patients, but rational steps towards a stated outcome must be the standard. Finally, education must be a major effort. We need to start by education of the patients about health care and its rational basis. Then we must get every type of health professional school to incorporate basic sciences relevant to pain in their core curricula. Clinical education must also be amplified to get pain management into the prominent position it deserves. Finally, every clinical training program for physicians must adopt standards for pain management education within its discipline. And then we need a small number of high quality fellowships to train the next generation of pain managers. All of these will require strong leadership in the pain world; we must present a coordinated front to those who do not understand what or why we do things.

WILL PAIN BE ABOLISHED ?

The abolition of acute post-operative and post-traumatic pain is a possible outcome of the explosion in our understanding of the mechanisms of pain. The problem is the need to develop a method of temporary abatement of pain, as the permanent loss of all perception of tissue damage is already recognized to be a potentially lethal and socially disruptive event. Children born with the congenital inability to perceive tissue damage develop Charcot joints, infections, corneal abrasions and unacceptable strategies for manipulating their parents and their environment. Most do not survive into adulthood, and those that do, are usually physically and socially deformed. I recommend Andrew Miller's "Ingenious Pain" for those who wish to read a fascinating novel that centers upon this issue (12).

A regionally active, temporary blockade of nociception or dorsal horn function has great promise to improve the well-being of those who undergo surgery or trauma. Agents that specifically block channels located only upon A delta and C fiber axons or that are transported by the membranes of such axons and then disrupt RNA transcription are already utilized in experimental animals. Drugs that modify central processing and increase modulation at the dorsal horn may also become available. More widespread use of psychological strategies to reduce anxiety and fear will also reduce pain in this setting. These strategies will be introduced by pain specialists but should rapidly move into the province of all physicians who deal with post-operative and post-traumatic pain. Their continued use will not be dependent upon the specialty of pain management, but development and refinement will be centered in research laboratories that direct their activities to pain.

Chronic pain management will not fare as well. First, we still have many uninformed physicians, lawyers, administrators and the public to contend with. Pain specialists may also fall into this category. There are so many arguments about the nature of chronic pain that it is naïve to think that more science will resolve them. I am reminded of the State of Kansas, whose Board of Education voted to abolish the teaching of evolution and cosmology to schoolchildren. It has been proposed that these subjects should be required for admission to all colleges so that the children of Kansas would be suitably punished for the behavior of this ignorant and irresponsible Board.

The complex nature of chronic pain, related to tissue damage, injury to the nervous system, affective state and the interaction with the environment will long delay its resolution into manageable components that can be targeted by pharmacological, psychological or physical interventions (13). The need for all health care providers to do that which they earn a living doing, in spite of the absence of evidence for efficacy, is also a big issue. Our ignorance of the natural history of most chronic pain patients also makes outcomes-research difficult. Finally, there is the epistemological problem of the inherent nature of chronic pain and its genesis. To the extent that this is a phenomenon of industrialized societies, the treatment cannot focus upon the individual sufferer, but must be directed at the social structure and physical environment in which the individual works and plays. This is a tall order, and falls outside the customary purview of medicine in general and pain specialists in particular. It is tempting to predict that chronic pain will be seen as a by-product of the industrialized society in the 20th century and, perhaps, those that will follow. As Fordyce stated, "Pain is a transdermal phenomenon."

However, there are some chronic pains, such as those that follow cancer or a defined injury to the nervous system, that do have their primary locus within the patient. These can be addressed through research, both clinical and basic, and we have every right to expect that molecular biological approaches will eventually lead to an understanding of their pathogenesis and the development of successful therapies. Pain specialists will be important in focussing attention upon these patients and in developing new treatments based upon basic science advances.

WILL PAIN SPECIALISTS DISAPPEAR ?

This is not a trivial question when one is addressing a pain society meeting. However, from the perspective of a nation's health care delivery system, the advent or demise of pain specialists is not likely to be noted. This is especially true in the USA, where the majority of pain specialists are anesthesiologists who will just retreat to the operating room if pain medicine disappears. The huge schism between pain specialists who believe that most patients with chronic pain need procedures or treatments and those who believe that a comprehensive, multidiscplinary approach is required has led to confusion in the market place. Since we live in a procedure-oriented system in the USA, it has been difficult to widen the horizons of those who pay the bills and make policy decisions in state and federal health care systems. Furthermore, the dollars of the drug and device manufacturing industry are potent in both state and federal legislative and administrative decision-making. Multidisciplinary pain medicine has much less clout. We could easily lose sight of the fact that a proceduralist who treats patients with pain may, or may not, be a pain management specialist. A radiologist who interprets imaging studies of those who hurt is not considered a pain specialist. Until the pain management movement can speak with one voice, we are in real jeopardy in either a managed care or a fee for service system. The politics of this issue has been identified for years, but no resolution appears immanent to me.

For pain management to survive as a medical discipline, we are going to have to work very hard. First we must define our mission and the boundaries of our activities. Second, we must show the public why we are better than other providers at producing the desired outcomes. Third, we must figure out how to get paid for doing our jobs. Fourth, we must produce outcomes data if we are to sell ourselves as an integral part of a 21st century health care system.

Physicians entered the last millennium as priests and left it transformed into the lay priests of the welfare state. Today, we have technical and dehumanised medicine devoid of a cultural language, without philosophy and soon, devoid of books. Although medicine may triumph in the twenty-first century, doctors are likely to be replaced by health technicians. Patients, however, will still be in need of a sympathetic physician who will support their perseverance, courage, hope, and trust. Hopefully, pain management will be part of that physician's repertoire.

REFERENCES

1. Bonica, JJ. The Management of Pain, First Edition. Philadelphia, Lea and Febinger, 1953.
2. Behan, RJ. Pain: its origin, conduction, perception and diagnostic significance. New York, Appleton, 1914.
3. Personal communication from Dr. H. H. Waldvogel, 2001.
4. Livingston, WK. Pain Mechanisms. Springfield, Thomas, 1943.
5. Melzack, R. and Wall, PD. Pain mechanisms: A new theory. Science. 1965, 150:971-979.
6. Loeser JD. Perspectives on pain. In: Clinical Pharmacology and Therapeutics , edited by. Turner P. MacMillan Publishers, London. 1980, 313-316.
7. Melzack R, Loeser JD. Phantom body pain in paraplegics: Evidence for a central "pattern generating mechanism" for pain. Pain. 1978, 4:195-210.
8. Loeser JD. What is chronic pain? Theor Med. 1991, 12:213-225.
9. Fordyce, W. Pain in the Workplace. Seattle, IASP Press, 1995.
10. Loeser JD, Henderlite S and Conrad D: Incentive effects of worker's compensation benefits: A literature synthesis. J Health Politics Policy and Law. 1995, 52:34-59.
11. Illich, I. Medical Nemesis. New York, Pantheon, 1982.
12. Miller, Andrew. Ingenious Pain. 1999. San Diego, Harcourt Brace & Co.,1997.
13. Loeser, JD. and Melzack, R. Pain: an overview. Lancet. 1999, 353:1607-1609.