Pain is a common experience and a frequent reason prompting a visit to a health care provider. The capacity to sense pain plays an important protective role in warning of current or potential tissue damage. The response to tissue injury (as well as painful stimuli) includes adaptive changes that promote healing and avoid further irritation to the injured tissue.
The experience of pain is most commonly associated with tissue damage such as a strained muscle, sprained ligament, or fractured bone. It is expected that when the tissue damage repairs, the pain will resolve. This type of pain is related to stimulation of tissue nociceptors (pain sensors) found throughout the musculoskeletal system which in turn stimulate sectors of the cerebral cortex of the brain where pain is perceived.
Nociceptive pain is typically described as deep, dull, aching and diffuse. Pain induced by nociceptive pain mechanisms is the most common variety seen in clinical practice. When the underlying problem is non-nervous system damage, healing of the tissue most commonly leads to resolution of pain in a predictable time frame.
Sometimes pain is associated with damage to nerves (neuropathic pain) which can involve parts of the central nervous system or peripheral nervous system. Neuropathic pain tends to last longer and can become chronic and persistent. Patients are more likely to develop disability associated with chronic, persistent pain when the damage involves the nervous system.
Chronic neuropathic pain appears to alter the brain in ways that perpetuate the pain syndrome and make it harder to treat. Patients are more likely to use adjectives such as shooting, stabbing, lancinating, burning, and searing to describe it, and often complain of pain worsening at night.
One key diagnostic feature of neuropathic pain is the presence of pain within an area of sensory deficit. Another feature is allodynia, in which a normally innocuous stimulus produces a sensation of pain whose quality is inappropriate for the stimulus. An example of this is the patient who cannot tolerate a blanket resting on an affected area of the body.
Neuropathic pain can be classified on the basis of the cause of the insult to the nervous system, the disease or event that precipitated the pain syndrome, or the distribution of pain. Certain medical conditions are associated with neuropathic pain, and these commonly include diabetes, HIV infection or AIDS, multiple sclerosis, cancer chemotherapy, malignancy, spinal surgery, alcoholism, herpes zoster, and amputation. Cancer patients can develop neuropathy from tumor invasion, and are also at higher risk for neuropathic pain following chemotherapy or radiation therapy.
Diabetes is associated with peripheral neuropathy and radiculopathy. HIV is associated with a variety of neuropathies and myelopathies. Multiple sclerosis is associated with neuralgia and neuropathy. Failed spine surgery is associated with radiculopathy. Amputation is associated with neuroma and neuropathic phantom limb pain.
Trauma can lead to the development of entrapment neuropathies, as well as partial or complete nerve transection, plexopathies (disorder of nerves in the brachial or lumbosacral plexus), and painful scars. Entrapment neuropathies such as carpal tunnel syndrome are usually characterized in the early stages by paresthesia (altered sensation) and pain.
Whatever the underlying cause, chronic, persistent pain can be extremely disabling for patients. Traditionally there is a tendency to approach pain treatment in a unimodal (single therapy) manner, which is limited and does not always lead to best outcomes. It is clear that there is a need to approach chronic, persistent pain management in a multimodal fashion, which takes into account biological factors as well as psychosocial factors.
Review of the biopsychosocial model of chronic pain
Historically, the concept of pain, even chronic pain, depended on a direct relationship between identifiable tissue damage or pathology and symptoms reported by the patient. The amount of pain was expected to be proportional to the amount of tissue damage “causing” the pain. These are considered biological mechanisms, which are important and should be addressed initially with all pain patients.
Also, traditionally, psychosocial factors were thought to be primarily important mechanistic contributors to pain only in cases where no identifiable pathology was present. This type of pain was labeled as “psychogenic” which likely led to stigmatizing chronic pain for many patients.
Dr. Mark Pfefer, a chiropractor, and the director of research at Cleveland University-Kansas City, believes patients must be examined more carefully to find the source of their pain.
“Chiropractors often see patients with chronic, persistent pain problems and find that it is vitally important to first understand the underlying and initiating biological diagnosis, and then to assess and characterize the unique, individual inter-relationships between psychological states, social issues, and contextual issues for each patient, to improve outcomes,” Pfefer said.
Over the past five decades, a biopsychosocial understanding has come to dominate the scientific community’s description of chronic pain, although to this day treatment is still often unimodal and siloed depending upon the type of health practitioner that is seen. Also, insurance reimbursement is often limited for patients to gain access to appropriate multimodal interventions. This new approach was described as an option that would obviously address the biologic aspects of the pain, but additionally, would appropriately address the social, psychological, and behavioral dimensions of illness.
Biomedical treatments for chronic pain have not been uniformly effective, and sometimes have caused harm. As a result, many guidelines have promoted treating chronic pain using nonpharmaceutical, noninvasive interventions such as manual therapies, exercise, and biopsychosocial therapies. Recent data reflects rising costs for spinal surgeries, whereas manual therapy, exercise intervention, and biopsychosocial pain treatments continue to be poorly reimbursed (if at all), and are not always widely available.
Manual therapies promote improved movement and may allow a patient with chronic pain to more easily engage in exercise. Therapeutic exercises represent an important part of the treatment program for most patients with pain, keeping in mind that most patients will have varying degrees of deconditioning that can range from mild to severe.
It is time for patients with chronic pain to have access to a variety of providers who not only have expertise in the biomedical model, but also providers who have expertise in non-pharmacologic strategies for treating pain, including those with training in cognitive behavioral therapy, exercise intervention, acupuncture, and a variety of manual therapies.
For example, the Joint Commission is an independent organization that accredits and certifies nearly 21,000 health care organizations and programs in the United States. They currently recommend that both pharmacologic and non-pharmacologic strategies have a role in management of pain, and identify several options including acupuncture, chiropractic therapy, osteopathic manipulation, massage therapy, physical therapy as well as relaxation therapy and cognitive behavioral therapy.
The American College of Physicians (ACP) 2017 Guidelines published in the Annals of Internal Medicine, present evidence and provide clinical recommendations on non-pharmacologic management of back pain. The ACP recommends that clinicians and patients should initially select non-pharmacologic treatment including superficial heat, massage, acupuncture, or spinal manipulative therapy for back pain.
Patients with pain often decrease their level of physical activity due to concern that they may exacerbate pain or produce tissue damage. The consequences may include reduced flexibility, decreased strength, muscle wasting, and overall deconditioning. Best practice approaches for patients with chronic, disabling pain include detailed, individualized assessment and recommendation for a combination of biopsychosocial and judicious use of biomedical interventions.
