The impact of Descartes' work would reduce thinking about the mind, and its relation with the body, and the perception of pain well into the 20th century. However, Descartes' work was a positive step for science, medicine and humankind. He inspired many scientists to continue working toward a better understanding of pain.

 

Charles Bell and Francois Magendie, a Scottish anatomist and neurosurgeon and a French physiologists, respectively, showed how the ventral nerve roots in the spinal cord were related to motor effects, while the dorsal horns were primarily sensory.  During the 19th century, Muller’s Law of specific nerve energies, postulated that different nerves reacted differently to unlike stimuli. Max Von Frey’s  work on pain spots in the hand, and Sir Charles Scoot Sherrington’s studies defined the concept of nociception.

 

Silas Weir Mitchell, an American physician, often called, "A Father of American Neurology, lived through the bloodiest war in American history: The American Civil War. Wounded veterans, surviving the battlefields, provided Mitchell with a large variety of injuries, creating a hands-on laboratory in which to study pain. Along with William Williams Keen, general surgeon, and George R. Morehouse, another early American neurologist, Mitchell first applied the terms causalgia, reflex sympathetic dystrophy and secondary paralysis to pain. In 1864, their findings were detailed in the work, "Gunshot Wounds and Other Injuries of the Nerves and Reflex Paralysis". These descriptions were later amplified by Dr. Mitchell in his book, "Injuries of Nerves and Their Consequences (1872)".

 

While observing his patients and the evolution of their pain symptoms, he concluded an extraordinary observation, one that even he considered bizarre. He wrote:

 

"Perhaps few persons who are not physicians can realize the influence which long-continued and unendurable pain may have on both body and mind. . . Under such torments the temper changes, the most amiable grow irritable, the soldier becomes a coward, and the strongest man is scarcely less nervous than the most hysterical girl.

Perhaps the older books are full of cases in which, after lancet wounds, the most terrible pain and local spasms resulted. When these had lasted for days or weeks, the whole surface became hyperanesthetic, and the senses grew to be only avenues for fresh and screaming tortures... Nothing can better illustrate the extent to which these statements may be true than the cases of burning pain, or, as I prefer to term it, Causalgia, the most terrible of all tortures which a nerve wound may inflict." [1]

 

Today we wonder why this discovery could baffle Mitchell. However, in his time, like others before him, his understanding was that the body was a machine which reacted to external stimuli. The mind did not affect the body. So why were these patients, heroes of war, acting in such way? Could the human body actually be related to its mind and could it cause the bodily feeling of pain without external stimulation?

 

Reading Mitchell's book, one understands the dedication and commitment he possessed. It is not possible, from the vantage point of today, to imagine what Mitchell must have felt. One can imagine his satisfaction with these new ideas, but at the same time he must have been terrified of proposing another mistaken belief. Mitchell reveals none of these conflicts in his writings.

 

He would extend his early observations of battlefield medicine, and he continued examining patients with a scientific approach, one that would lead him to yet more discoveries, including the following:

 

"We have some doubt as to whether this form of pain ever originates at the moment of the wounding. . . Of the special cause which provokes it, we know nothing, except that it has sometimes followed the transfer of pathological changes from a wounded nerve to unwounded nerves, and has then been felt in their distribution, so that we do not need a direct wound to bring it about. The seat of the burning pain is very various; but it never attacks the trunk, rarely the arm or thigh, and not often the forearm or leg. Its favorite site is the foot or hand. . . Its intensity varies from the most trivial burning to a state of torture, which can hardly be credited, but which reacts on the whole economy, until the general health is seriously affected....The part itself is not alone subject to an intense burning sensation, but becomes exquisitely hyperanesthetic, so that a touch or tap of the finger increases the pain. Exposure to the air is avoided by the patient with care which seems absurd, and most of the bad cases keep the hand constantly wet, finding relief in the moisture rather than in the coolness of the application...As the pain increases, the general sympathy becomes more marked, the temper changes and grows irritable, the face becomes anxious, and has a look of weakness and suffering...At last the patient grows hysterical, if we may use the only term that describes the facts".[2]

 

 He believed there was a clear connection between the mind and body. Pain leads to changes in behavior, and in some instances to insanity. His use of the word "hysterical" and "girl" in reference to the description of a man, in that era, would be of great offense. However, these were the only words that he felt were appropriate.

 

After recognition of this phenomenon by medical practitioners, amputation became the gold standard therapy for patients experiencing severe pain with only slight external stimuli or no stimulation at all.

 

Mitchell came to a decisive observation about amputation, based on patient’s response to that treatment:

 

"Sensory hallucination. --- No history of the physiology of stumps would be complete without some account of the sensorial delusions to which persons are subject in connection with their lost limbs. . . Nearly every man who loses a limb carries about with him a constant or inconstant phantom of the missing member, a sensory ghost of that much of himself, and sometimes a most inconvenient presence, faintly felt at time, but ready to be called up to his perception by a blow, a touch, or a change of wind."[3]

        

Phantom Limb Pain became an interesting topic in his search to understand pain mechanisms, but that subject merits a separate paper. Mitchell performed various experiments in his quest to understand causalgia. Even though a comprehensive explanation did not emerge, his research would influence others to continue the hunt. It would be another more recent war that would help Rene Leriche to provide the next significant step forward in the understanding of pain.

 

Rene Leriche, a French surgeon, saw many soldiers with peripheral nerve injuries during World War I.  In his book "La Chirurgie de la Douleur" he detailed his findings on causalgia and phantom limb. It is a book truly dedicated to the understanding of pain.         He mentions the work of Mitchell along with the observation that no one had seen much of these injuries in Europe. Skepticism towards Mitchell findings, remained. However, Leriche wrote:

 

"...the majority of French surgeons, in August,1914, would certainly have had no suspicion of the existence of causalgia, though it was a matter of quite common occurrence during the American Civil War; and, alas! was about to become so once more for them. It was not long, indeed, before, on all the war fronts, it became evident that many wounds of the soft parts of the limbs were followed by a painful syndrome of a very peculiar type".[4]

 

Perhaps Leriche's greatest contribution was his description of sympathetic dysfunction related to the patient's symptoms.  Even though it was described earlier, by other scholars and physicians, Leriche did more meaningful work in describing sympathetic dysfunction. He called it "the wound of the sympathetic". He can also be credited for being one of the first to perform sympathetic nerve blocks on these patients with good results. Leriche speculated that, because the pattern of nerve damage followed the pattern for vasculature supply, perhaps the damage was to the sheath of the vessel itself.  He wrote:

 

 "...And remembering that the sympathetic, in its distribution to the limbs, follows the course of the arteries, I asked myself whether, in those cases of nerve injury complicated by arterial wounds, it was not the injury to the sheath of the vessel that determined their painful and trophic features".[5]

 

Leriche had a patient who had a bullet wound on his right axilla. He decided to remove the patient's brachial artery adventitia. The patient showed great improvement in symptomatology and Leriche went on to publish his observation.  At first he relates that there was great disbelief of his work but later on, it became widely adopted :

 

"...I was a little uneasy as to the reception which might be accorded to this new conception, which had not previously occurred to anyone. My feeling of disquiet was justified, for its reception was chilly enough...a few months later...the theoretical considerations to which I have already alluded, the sympathetic origin of causalgia has come to be admitted by everybody".[6]

 

With the work of Mitchell and Leriche as foundations, yet another war, brought forward additional significant contributors to the understanding of pain. William K. Livingston.  Livingston, an American general surgeon, emphasized his work on the understanding of visceral pain.  He wrote, in his book "The Clinical Aspects of Visceral Neurology" :

 

"My interest in the subject began as an interne when I first witnessed the opening of a colostomy with a cautery. The fact that the patient experienced no pain during the procedure impressed me, and led me to a study of the phenomena of visceral sensibility...I found myself drawn into a rapidly enlarging field which has since engaged much of my time and attention".[7]

           

However, World War II would present Livingston experiences in the effects of war on injured soldiers. His experienced were described in his book, "Pain Mechanisms". Reading this text evokes admiration and humility. He challenged old and new theories. His detailed  explanation of findings, treatments and reactions helps to understand the importance of his work. In his book's (Pain Mechanism) foreword, Ronald Melzack, an emerging pain expert, wrote the following:

 

"The field of pain research and theory has suddenly come alive-full of new concepts and therapeutic approaches. No one in this century has contributed more to this breakthrough than William Kenneth Livingston. Pain Mechanisms, which he published in 1943, was the first major critique of the traditional specificity theory of pain and marked the beginning of new ideas that evolved to produce the remarkable explosion of research and new forms of treatment that have occurred..."[8]

 

Livingston was a firm believer in keen, detailed observation and treatment in the clinical setting. He believed this required the same dedication and rigor as should be applied in the research laboratory. He further emphasized that there needed to be strong communication between clinic and laboratory to promote better understanding and treatment of pain.

 

"It is probable that neither the clinician nor the anatomist will ever be able to supply a final answer to the questions that have been enumerated. Perhaps the physiologist can do it when his investigations have progressed further. Until the physiologists accepts this challenge and can tell us the "why" and "how", we clinicians can go a long way toward establishing a practical, if not complete, answer, and in so doing may discover methods of treatment not only for the pain syndromes under immediate scrutiny but for other disease processes as well".[9]

 

Livingston also felt that theories should be based on objective findings not on old beliefs. This would lead him to refute many theories, specially the most accepted theory for centuries: Descartes' theory of straight-through transmission with the reflex response serving as a protective mechanism.

 

"...His thesis that pain, accompanied by protective muscular spasm, is Nature's "warning signal", forms the basis on which pain is interpreted as a conservative and beneficent mechanism. Unfortunately, however, pain does not always stop, once it has accomplished its defensive purposes. And, as will be emphasized in subsequent chapters, when pain exceeds its protective function it becomes destructive".[10]

 

Rereading Livingston's work today, 60 years later, one could easily conclude his writings and research were advanced. They could profitably be learned, even today, by anyone pursuing a better understanding of pain. Livingston's teaching and collection of case reports influenced the development of the Gate Control Theory for pain, and the McGill Pain Questionnaire.

 

In 1965 Ronald Melzack, a Canadian psychologist, and Patrick Wall, a British physiologists, published in the magazine Science, their paper, "Pain Mechanisms: A new Theory". Now commonly called the Gate Control Theory, it described a gating mechanism by which, at the level of the spinal cord, fast conducting fibers and slow conducting fibers elicit excite or inhibit transmission. The fast fibers are the sensory fibers that the cord interpreted as touch, whereas the slow conducting fibers are interpreted as pain. Perhaps the most influential paper written in the study of pain, it produced a broad positive response within the scientific community. The Gate Control Theory is widely understood now, but has undergone considerable modifications.

 

There is a direct connection between Ronald Melzack and William Livingston. Beginning in 1953, in the laboratories at the University of Oregon, Portland, they worked together. After a year at the laboratory facilities, Melzack was asked by Livingston to work in the pain clinics. Melzack, much like Weir Mitchell, had a keen interest in the differing descriptions by patients about their pain. The McGill Pain Questionnaire, still used today worldwide, was the direct result of Livingston and Melzack's collaboration.

 

The relationship between mind and body, and their influence on pain helped developed John Bonica's multidisciplinary approach. Bonica‘s, an anesthesiologist, approach to the pain patient supported the new ideas about pain mechanisms. Those ideas consist of multifactorial sensory inputs which both the body and mind perceive. Interaction among pain stimuli, past experiences, a patient's health, and the environment all affect the overall response to both pain and therapy.

 

Many minds contributed to the development of Pain Medicine. They were influenced by three different wars. The modern understanding of pain and its treatment resulted from the experiences gained in treating war wounded patients.

 

What is very hard to imagine, is where would the study of pain be today if these men had not researched common questions: What, if anything, causes a patient to have pain without external stimuli? What is causalgia and how do you explain it? Pain patients have been criticized and accused of psychosis. Analyses of their painful conditions, coupled with science, led to better understanding and to better, more integrated relationships of pain responses and their treatment.

 

---

 

[1] Mitchell S.W. Injuries of Nerve and Their Consequences. Philadelphia: J.B. Lippincott Co. 1872.196.

 

[2] Mitchell S.W. Injuries of Nerve and Their Consequences. Philadelphia: J.B. Lippincott Co. 1872.197.

 

[3] Mitchell S.W. Injuries of Nerve and Their Consequences. Philadelphia: J.B. Lippincott Co. 1872.348.

 

[4] Leriche R. The Surgery of Pain. London: Bailliere, Tindall and Cox. 1939 (translated by Archibald Young).172.

 

[5] Leriche R. The Surgery of Pain. London: Bailliere, Tindall and Cox. 1939 (translated by Archibald Young).172-173

 

[6] Leriche R. The Surgery of Pain. London: Bailliere, Tindall and Cox. 1939 (translated by Archibald Young).175.

 

[7] Livingston W.K. The Clinical Aspects of Visceral Neurology: with Special Reference to the Surgery of the Sympathetic Nervous System. Illinois/Maryland: Charles C. Thomas. 1935.vii.

 

[8] Livingston W.K. Pain Mechanisms: A Physiologic Interpretation of Causalgia and Its Related States. New York. Plenum Press; 1976.

 

[9] Livingston W.K. Pain Mechanisms: A Physiologic Interpretation of Causalgia and Its Related States. New York. Plenum Press; 1976.11-12.

 

[10]Livingston W.K. Pain Mechanisms: A Physiologic Interpretation of Causalgia and Its Related States. New York. Plenum Press; 1976.44-45.