CHRONIC NON-MALIGNANT PAIN

 CHRONIC NON-MALIGNANT PAIN

Chronic-Pain

Chronic-Pain

Chronic pain often produces significant changes in mood (e.g., depression) and lifestyle. Unrelieved pain may produce a decline in a person’s routine activities and participation. Despite the magnitude of pain and suffering, chronic pain is often undertreated. The reasons for this include the low priority of providing consumers with pain relief in the healthcare system, lack of knowledge of pain interventions among healthcare professionals, and fear of opioid addiction among many healthcare professionals and the public. Unfortunately, healthcare professionals often do not receive adequate education or training regarding appropriate evaluation and intervention for pain.

COMMON CHRONIC PAIN SYNDROMES:

Pain can be categorized by location or syndrome. In most persons with the complaints described below, usually the pain, not the underlying pathology, prevents them from achieving a productive and satisfying lifestyle.

Low Back Pain:

Most persons receiving physical therapy for pain complain of low back pain (LBP). Approximately 3 to 7% of the population in Western industrialized countries experience chronic LBP. The impairment and disability associated with LBP often results in job absenteeism, loss of productive activity, and decreased participation. The most common causes of LBP are injury or stress resulting in musculoskeletal and neurologic disorders in the lumbosacral region (e.g., disk lesions, muscle spasm, sciatica). Pain may also result from infections, degenerative diseases,malignancies, and aging. Poor posture may cause spinal disk degeneration and thus lead to LBP .LBP tends to improve spontaneously over time.

Chronic-Pain

Headaches:

Migraine and tension headaches are very common chronic pain complaints. Approximately 28 million Americans, roughly 18% of women and 6% of men, experience recurrent migraine headaches. Experimental evidence supports the role of serotonin in migraine. Stress, attention, and mood (e.g., anxiety) affect these headaches. In contrast, tension headaches are generally considered to be muscular in origin. There is not sufficient evidence, however, for a specific pathophysiology.

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Myofascial Pain Syndrome:

Myofascial pain syndrome (MPS) refers to a large group of muscle disorders characterized by highly sensitive trigger points within muscles or connective tissue. Myofascial pain is predominant and is perceived as a continual dull ache often located in the head, neck, shoulder, and low back areas. The trapezius muscle is one of the most commonly affected muscles. Myofascial pain may result from an acute strain caused by a sudden overload or overstretching of the muscle.

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Fibromyalgia:

The prevalence of fibromyalgia ranges from 0.7 to 3.2% in the adult population. Fibromyalgia should not be confused with MPS. Although MPS and fibromyalgia may overlap clinically,they are two distinct pain syndromes. Skeletal muscles have been implicated as the cause of fibromyalgia, but no specific abnormalities have been identified. Abnormalities of the neuro-endocrine system, autoimmune dysfunction, immune regulation, sleep disturbances, and cerebral blood flow difficulties have also been suggested.

Fibromyalgia-Pain

Chronic Pain Secondary to Physical Disability Only recently has pain been investigated in persons who already have a physical disability. Chronic pain is a common problem following spinal cord injury (SCI). A recent community survey indicated 79% of adults with SCI reported a recurrent pain problem. Pain may occur above, at, or below the level of injury in both complete and incomplete injuries. Neuropathic or central pain is the most frequent type of chronic pain in SCI and is believed to originate from abnormal processing of sensory input owing to damage to the central nervous system. Musculoskeletal pain complaints may result from a variety of factors, including wheelchair use.

A typical consequence of amputation is phantom limb pain(PLP). As many as 85% of persons who undergo limb amputation will experience phantom limb pain. Residual limb pain (“stump pain”) was reported by 72% of community-dwelling adults with lower limb amputations. Back pain has also been identified as a significant problem among many individuals with lower limb amputation. Adults with cerebral palsy frequently experience recurrent pain. Sixty-seven percent of a community sample reported chronic, bothersome pain. Low back and leg were identified as the most frequent sites. Pain has been associated with spasticity, scoliosis, and bony deformity resulting from spasticity.

Phantom-Pain

VIEWS OF PAIN:

Because pain is viewed as being multidimensional and subjective, numerous theories and models exist to explain pain. Ideally, theories and models of pain transmission explain the range of pain phenomena.


Specificity Theory:

The specificity theory was an initial attempt to explain the way the nervous system processes nociceptive (noxious stimuli) information. In 1894, Von Frey proposed that the sensation of pain resulted from a direct communication from specific pain receptors in the periphery to a central pain center in the brain. Physical characteristics of the pain stimulus (e.g., sharp quality) are transmitted from the pain receptors (free nerve endings) along specific peripheral nerve fibers (A-delta and C fibers) to the spinal cord. In the spinal cord, these impulses are conducted via the anterolateral spinothalamic tract to the brain (thalamus and higher centers), where they are then perceived as pain. Recently this theory has been criticized given current, observed clinical phenomena. The specificity theory assumes a direct relationship between stimulus intensity and perceived pain, yet the same stimulus may evoke varied responses in different individuals or even in the same individual under different conditions. In addition, interruptive surgical procedures like rhizotomy do not consistently eliminate pain despite interrupting this theoretical route of pain transmission.

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Pattern Theory:

The pattern theory of pain transmission was proposed to address some of the limitations of the specificity theory. In 1894, Goldschneider suggested that it is not the direct stimulation of specific receptors, but the transmission of nerve impulse patterns coded at the periphery which causes the pain sensation. This theory proposes all nerve endings are alike, and the perception of pain is produced by intense stimulation of nonspecific receptors. The combination of direct stimulus added to other sensory inputs inform the central nervous system that pain is present. A key concept of this theory is the explanation it provides for phenomena such as phantom limb pain, in which the pain sensation continues to occur after the cessation of local stimulation. Several authors have criticized the pattern theory because it ignores evidence of receptor-fiber specialization such as the potential success of surgical procedures like cordotomy.

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Gate Control Theory:

Melzack and Wall offered a variation of the pattern and specificity theories to explain pain transmission. They suggested that skin receptors have specific physiologic properties by which they may transmit particular types and ranges of stimuli in the form of impulse patterns. According to this theory, pain is modulated by a “gating” mechanism located in the spinal cord that can increase or decrease the flow of nerve impulses to the brain. Afferent impulses can travel to the dorsal horn along large (A fiber) and small diameter (A-delta or C fiber) nerves associated with pain impulses. At the dorsal horn, these impulses encounter a gate thought to be substantia gelatinosa cells, This gate, which may be presynaptic or postsynaptic, can be closed, partially opened, or opened. When the gate is closed, pain impulses cannot proceed. When the gate is at least partially open, impulses stimulate T (transmission or trigger) cells in the dorsal horn which then ascend the spinal cord to the brain and pain perception results. Once the pain impulses are perceived, higher central nervous system structures (i.e., brainstem, thalamus, and cerebral cortex) can then modify pain by influencing T-cell activity. These structures can alter attention, memory, and affect, thereby

contributing to an individual’s unique pain perception. Although the anatomic and physiologic bases of the gate remain controversial, this theory has been instrumental in furthering multidimensional pain evaluation and intervention. The gate control theory of pain implies psychology has much to offer in both understanding and treating pain. Motivational and cognitive processes thereby are examined in terms of their contribution to the pain experience.

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Loeser’s Model:

Loeser proposed a biopsychosocial model of pain that suggests the phenomenon of pain can essentially be divided into four domains: nociception, pain, suffering, and pain behavior. Nociception is the detection of tissue damage by transducers in the skin and deeper structures and the central transmission of this information by A-delta and C fibers in the peripheral nerves. Pain thereby is the perception and interpretation of the nociceptive input by the highest parts of the brain. Suffering is the negative affective response to pain. It may be difficult to differentiate suffering from fear, anxiety, isolation, or depression. Lastly, pain behavior is what an individual says or does (e.g., taking medications) or does not say or do (e.g., job absenteeism), which leads others to believe that individual is suffering from noxious stimuli. Only pain behaviors are observable and measurable. Culture and environmental consequences influence pain behaviors. According to this model, one can experience or demonstrate some elements of the model in the absence of others. In chronic pain, pain behaviors and suffering often exist in the absence of nociception.

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ROLE OF THE PHYSICAL THERAPIST:

Evaluation

The importance of adequate pain evaluation is being increasingly recognized in healthcare. Hospitals, outpatient clinics,home care agencies, nursing homes, and health plans accredited by the Joint Commission on Accreditation of Health Care Organizations require staff members to be competent in pain assessment. The American Pain Society (APS) has identified pain as the fifth vital sign. In addition, a goal of Healthy People is the promotion of the health of people with disabilities and the prevention of secondary conditions such as chronic pain. The inability to communicate verbally should not preclude pain assessment and treatment. Successful pain interventions are often predicated on accurate evaluation of the pain complaint. Proper evaluation requires the use of valid and reliable instruments for determining the need for intervention and its effects.

PHYSICAL EXAMINATION:

Traditionally, doctors have relied on clinical tests of impairment when evaluating the consumer. These tests, however, correlate poorly with self-reports of chronic pain and dysfunction. Standardized tests of range of motion and muscle strength lack sensitivity, specificity, and responsiveness. Complex and expensive isoinertial and isokinetic devices measure strength, range, and velocity of motion reliably, but the individual’s performance can be affected greatly by factors such as fear of injury, motivation, and mood. In addition, use of these devices does not simulate activity performance and participation.

FUNCTIONAL PERFORMANCE:

Chronic-Pain

Clinical improvement can be measured as improvements in activity performance and participation. The Brief Pain Inventory is a reliable and valid instrument used to measure pain interference. Consumers rate on an ordinal scale how much their pain has interfered with general activity, mood, mobility, work, interpersonal relationships, sleep, enjoyment of life, self-care, and recreation.

PAIN INTENSITY:

Because pain is a private experience that cannot be observed directly, assessment of the pain experience is frequently through self-reports. A reduction in pain intensity is typically the primary reason a consumer seeks services. Numerous measures exist to assess the severity of pain. The three most common measures are the verbal rating scale (VRS),the numerical rating scale (NRS), and the visual analog scale (VAS). The VRS consists of a list of adjectives ranging from no pain to extreme pain to describe different levels of pain. In contrast, the NRS requires consumers to rate their pain on a scale from 0 to 10 or 0 to 100, with the understanding that 0 is equal to “no pain” and the 10 or 100 is equal to the “most excruciating pain possible.” Finally, the VAS consists of a 10-cm line for which the ends are labeled as the extremes (e.g., “no pain” to “pain as bad as it could be”). These rating scales are easy to administer and score, have good evidence for construct validity, are sensitive to treatment, and are used fairly reliably by consumers.


PAIN BEHAVIORS:

In accordance with Fordyce’s seminal work and Loeser’s model of pain,pain behaviors are to be considered in evaluation and intervention. For some individuals with severe disabilities pain behaviors are the only way to communicate pain.

For others, pain behaviors can be explored within the context of functional analysis. Functional analysis can determine the degree to which pain behaviors are influenced by social and environmental variables suggested five options for assessing pain behavior:

- continuous observation

- duration

- frequency

- time sampling (counting behavior at prespecified time intervals).

- interval recording (observation broken into equal-length intervals)


CULTURAL, FAMILIAL, AND SPIRITUAL INFLUENCES: 

Cultural, familial, and spiritual influences are other important factors to be considered in pain evaluation and intervention, especially when the pain etiology is unclear. Each culture, family, and religion has it own system of beliefs, attitudes, and values. The individual therefore may be rewarded, ignored,or punished for having pain behaviors. Intervention Pain interventions have changed dramatically over the years.

The focus of treatment has shifted from dealing with impairments to emphasizing increasing function. Healthcare consumers are no longer passive, and they expect practitioners to be accountable for provided services. A multidisciplinary team approach to chronic pain is common and includes the consumer as an active and educated participant.

The Commission on Accreditation of Rehabilitation Facilities (CARF) has identified pain management standards. Other key team members in addition to the physical therapist are a physician and a psychologist or psychiatrist. An occupational therapist, vocational counselor, or dietician may also provide evaluation and intervention. Chronic pain interventions strive to increase the consumer’s activity performance and participation as well as reduce reliance on healthcare providers.

ACTIVE REHABILITATION:

Physical therapy treatment goals may be achieved through physical restoration. An active rehabilitation program is not synonymous with exercise. In addition to prescribed exercises, an active rehabilitation program emphasizes behavioral strategies to help consumers better cope with and manage their pain. The primary assumption of this intervention is that the major physical deficit is the “deconditioning syndrome,” consequent to prolonged disuse of spinal joints and muscles. Physical therapy treatment therefore consists of individualized physical reconditioning exercises/activities based on objective quantification of physical functioning.

Treatment also needs to address long-term adaptations the body makes in its movement patterns and adaptations in connective tissue. Ideally the physical therapist collaborates with the consumer in the development and implementation of the treatment program. Consumers should be informed that they might experience a slight increase in symptoms with the initiation of treatment and that increased pain with increased activity does not equal harm.

WHAT IS THE ROLE OF THERAPEUTIC EXERCISE ?

Therapeutic exercise is a critical component of an active rehabilitation program. Exercise therapy is often prescribed for the relief of pain and improving function. Although rest may be beneficial for a few days after an acute injury, it is contraindicated for persons with chronic nonmalignant pain.

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Prolonged rest and inactivity result in decreased mobility,reduced strength, lessened cardiopulmonary endurance, increased joint stiffness, and postural strain. recommended that consumers be educated about the effects of deconditioning in addition to bodily changes occurring when an exercise program begins. Evidence-based research supports active rehabilitation programs as the most effective means of achieving pain relief and reducing disability for persons with chronic LBP.

The recent Cochrane Review of exercise for LBP indicated that exercises might be helpful for individuals to increase and tolerate routine activities of daily living, including work. It remains unclear,however, if any specific type of exercise (e.g., flexion or extension, strengthening) is superior. Success in an exercise program can make the difference between function and failure. Therefore, the physical therapist must assist the consumer in developing and implementing a daily exercise routine that is appropriate, structured, and meaningful.

SOFT TISSUE MANIPULATION EFFECT:

Soft tissue manipulations can be directed at muscle, ligaments, and fascial layers to restore mobility and extensibility impacted by pain.

FELDENKRAIS METHOD:

The Feldenkrais method is based on the premise that humans have a choice in developing habits of movement. In addition, mental and emotional activity are recognized as influencing human performance. The consumer is therefore invited to participate in intervention. Treatment consists of the physical therapist continually observing and then adapting stimuli to facilitate the consumer’s exploration and development of adaptive skills to maximize function despite pain.

QUOTA PROGRAMS:

Increasing the consumer’s activities and participation are the cornerstone of most chronic pain management programs. Intervention begins with a series of baseline trials in which the consumer is asked to perform a demonstrated exercise to tolerance. Tolerance is defined as the point at which an individual stops exercising because of pain or fatigue. Detailed pretreatment performances are documented. The physical therapist then establishes a quota for each prescribed mobility, strengthening, and/or cardiovascular endurance exercise/activity to be performed. Use of a quota system eliminates the linking of pain with function that often resulted in overdoing on “good days” and avoiding exercise on “bad days.” Initial quotas are slightly lower than baseline trials (approximately 75% of average) and are increased by predetermined small increments (typically 10% every few days) regardless of how the consumer feels. Treatment also involves positively reinforcing (e.g., praising) the consumer’s attempts and gains in functional performance. Resting before the quota is discouraged because it may reinforce pain behaviors. A gradual increase in activity demands also decreases the likelihood of an exacerbation of pain. Quota programs have been effective in increasing functional performance in persons with LBP. Modalities (heat or cold) may be applied to prepare the consumer for therapeutic exercise or the initiation of activities.

OPERANT TRAINING:

Pain behaviors can be severely disabling. Vlaeyen et al. used the operant principle of shaping (reinforcement of the small steps it takes to reach a goal) to increase sitting and standing tolerance in a consumer with chronic LBP after laminectomy.

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Each time a subgoal was achieved, a treatment team member provided social reinforcement. Treatment gains were generalized to a variety of settings and from an adjustable stool to a chair. Shaping principles were also successfully used to increase upper extremity use in adults with chronic pain and hysterical paralys. A recent Cochrane Review indicated there is strong evidence that behavioral treatment of adults with chronic LBP resulted in small to moderate decreases in pain intensity and improved functional performance.


MODALITIES:

The use of modalities for persons with chronic pain complaints is disputed. Some practitioners advocate for only using self-management interventions (e.g., exercise, relaxation) because chronic pain cannot be “fixed.” Other practitioners do use modalities (e.g., heat therapy, transcutaneous electrical stimulation) and massage as an adjunct to other interventions.

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BODY MECHANICS AND POSTURAL INSTRUCTION:

Instruction in and practice of proper body mechanics and postures that will not increase the risk of low back injury or strain are important for consumers experiencing both acute and chronic musculoskeletal pain as well as implications for primary prevention. There is a lack of consensus in the literature, however, about specific lifting techniques.

LUMBAR SUPPORTS:

Lumbar supports may be used to reduce impairment and disability in persons with nonspecific LBP. Lumbar supports may also be used to prevent recurrences of LBP episodes. The Cochrane Review of lumbar supports for prevention and treatment of LBP indicated there is limited scientific evidence to advocate for the use of lumbar supports in pain relief. There is some evidence that a lumbar support with a rigid insert in the back provides more overall improvement than a lumbar support without a rigid insert. In addition, there is conflicting evidence that consumers who use a lumbar support to return to work do so more quickly when compared with other interventions. In some active rehabilitation programs consumers are weaned from lumbar supports as well as braces, canes, crutches, and pain medications.

RELAXATION TECHNIQUES:

A variety of relaxation training strategies exist: autogenics; progressive, deep muscle relaxation; and guided imagery. Autogenics involves the silent repetition of phrases of self-directed formulas to describe the psychophysiologic aspects of relaxation (e.g., “My right arm is heavy”). The consumer passively concentrates on these phrases while assuming a reclined position, with eyes closed, in a quiet setting. The goal of this relaxation approach is to develop an association between a verbal cue (thought of relaxation) and a state of calmness. Progressive relaxation involves the systematic tensing of major musculoskeletal groups for a few seconds, passive focusing of attention on how the tensed muscle feels, and then release of the muscles and passive focusing on how relaxation feels. As the consumer learns to recognize the sensations of muscle tension, he or she can direct attention to inducing relaxation.

The rationale that underlies the analgesic effects of relaxation is that muscle tension results in pain. Muscle relaxation, therefore, will reduce or eliminate pain attributed to muscle tension. Guided imagery requires the consumer to develop a calm, peaceful image (e.g., a beautiful garden). He or she concentrates on that image for the duration of the pain or stress episode. The premise of this strategy is that an individual cannot concentrate on more than one thing at any given time.

A strong image is needed to divert attention away from the pain complaint. Relaxation training has been used successfully to relieve a variety of pain complaints, including headache, LBP, and myofascial pain. In fact, the National Institutes of Health concluded that, “The evidence is strong for the effectiveness of this class of techniques in reducing chronic pain in a variety of medical conditions.

BIOFEEDBACK:

Biofeedback refers to instrumentation used to provide consumers with immediate feedback of electronically monitored physiologic sites. This intervention assumes that a faulty body function causes pain, and that with feedback the consumer can learn to control the impairment. Biofeedback does not do anything to the consumer; it merely facilitates learning body control. Biofeedback for pain control is typically done in conjunction with relaxation training. Skin temperature biofeedback to increase digital temperature in vascular pain complaints (e.g., migraine headaches) and electromyographic (EMG) biofeedback to decrease skeletal muscle pain (e.g., tension headaches) are standard treatments in multidisciplinary pain clinics. An evidence-based review by Turner and Chapman revealed increased hand temperature resulted in decreased migraine headaches. Temperature changes, however, were not significantly correlated with symptom reduction. Therefore, other factors (e.g., suggestion, expectancy) may be responsible for the desired changes.

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Relapse Management
Consumers with chronic pain frequently experience an acute pain episode not related to their pain (nociception evident) or a significant exacerbation of their pain resulting from increased activity. Until the consumer has recovered from the acute incident, endurance (aerobic) conditioning exercises (e.g., walking, stationary biking, swimming) should be performed to help avoid dehabilitation from inactivity. An incremental, gradual increase in conditioning exercises can be implemented.

Evaluation and treatment of individuals with chronic pain is complicated. Chronic pain is best managed by prevention. Prevention reduces pain, suffering, healthcare costs, and the incidence of long-term disability. Physical therapists have a critical role in the prevention, evaluation, and treatment of chronic pain.