16 Physical Therapy
The Massachusetts General Hospital Handbook of Pain Management
Harriet M. Wittink and Theresa Hoskins Michel
Life begins on the other side of despair.
—Jean Paul Sartre (1905–1980)
I. Physical Therapy Evaluation
II. Physical therapy intervention
1. Education and self-management
2. Pain treatment and/or management
III. Patients with chronic pain
The goal of physical therapy is to restore or improve function and prevent disability. Referral to a physical therapist is appropriate when pain impairs a patient’s optimal functional ability or inhibits his or her independence in activities of daily living, or when physical rehabilitation is a necessary component for treating the underlying cause of pain. The physician supplies a diagnosis and communicates any precautions, thereby allowing the physical therapist to use clinical judgment in designing an appropriate treatment program. Although it is always appropriate to offer detailed prescriptions for specific functional evaluation and physical therapeutic modalities, an “evaluate and treat” order is also a reasonable means of asking a physical therapist to provide comprehensive assessment and a treatment plan based on this assessment. In either case, the key is collaboration between physician and physical therapist and integration of component therapies.
Physical therapists attempt to identify the relationship between pathology, impairments, functional limitations, and disability to direct treatment appropriately. In acute pain, a clear relationship exists between nociception, perceived pain, and impairments; therefore, treatment focuses on the elimination of pain. As a result, impairments diminish, functional ability is restored, and disability is prevented. In chronic pain patients, however, the relationship between pain, impairments, and disability is unclear. Treatment that solely addresses elimination of pain in patients with chronic pain will very likely fail to alter the illness and disability behavior of the chronic pain patient. Instead, treatment addresses function in spite of pain and promotes independence at a level of tolerance.
I. PHYSICAL THERAPY EVALUATION
Physical therapists are trained to assess physical impairments, such as flexibility, strength, and endurance. Through an interview and physical examination, most of the information needed to develop an appropriate treatment plan should be obtained. Although the physical therapist’s interview and examination closely resemble those of other health care providers, specific to the physical therapy examination is the observation of the patient’s movement patterns and willingness to move. Transitional movements are observed when the patient sits, stands, walks, or climbs onto a plinth. Important diagnostic features include quality of motion, which can be distorted and erratic, and dysfunctional movement patterns including muscle guarding and pain behaviors.
Functional testing helps to compare the patients’ perception of what they are able to do versus what they are can actually accomplish. Patients’ self-reports of their functional ability have been shown to be influenced by mood. Some functional tests that have been applied to a chronic pain population include the 5-minute walk test (meters walked in 5 minutes), number of stairs climbed in 1 minute, and the stand-up test (number of times a patient can stand up from sitting down in 1 minute).
A functional capacity evaluation (FCE) is usually performed to determine a patient’s physical capacity to perform work. Assessment includes the patient’s ability to lift weights from the floor to waist level and from the waist to overhead, carry, crawl, squat, sit, stand, walk, climb stairs, and push and pull weights. Aerobic fitness may be determined from a (submaximal) bicycle or treadmill test. Aerobic fitness represents the ability to generate energy and is part of the measure of a person’s work capacity. An FCE is always somewhat subjective as it can only document how much a patient is willing to do on a given day.
II. PHYSICAL THERAPY INTERVENTION
Physical therapy treatment should be time-limited and have an observable endpoint associated with the following:
Restoration of optimal physical functioning
Reduction of the impact of pain on the patient’s life (i.e., reduced disability)
Resolution of treatable impairments that interfere with normal function
Prevention of future occurrences
Improvement of the patient’s knowledge of independent pain management
Components of physical therapy intervention for pain include the following:
Teaching self-management techniques
Treatment or management of pain by active modalities (exercise) and/or passive modalities (massage, joint mobilization, electrotherapy, heat and cold)
1. Education and self-management
Perhaps the most important goal in educating patients and teaching them self-management techniques is increased self-reliance. Many patients report feeling helpless and hopeless and at a loss at understanding why they have pain. Increased selfreliance increases their participation in the intervention and leads to better outcomes. Educating them about their diagnosis and pathology is helpful in reducing fear and eliminating catastrophizing.
It is important that the patient agrees with the goals of treatment. For example, if a patient feels that the only helpful treatment is medication, the chances of a successful outcome from physical therapy intervention are slim. When patients understand their pathology and agree with the goals of intervention, they are more likely to be compliant with the intervention offered.
It is helpful to instruct patients in self-massage, applying heat or cold as an active pain-control modality whether they have acute or chronic pain. For self-massage, patients can use a cane or umbrella handle to press against a trigger point and apply ischemic pressure, or they can slowly rotate two tennis balls around a painful area. Heat and cold packs in all sizes are commonly available through pharmacies.
2. Pain treatment and/or management
(i) Active modalities
Active modalities can be subdivided into three categories: (a) stretching exercise, (b) strengthening, and (c) endurance exercise.
a) Stretching exercise
The purpose of stretching is to regain normal flexibility around joints to allow them to function in their optimal position. Muscle imbalance can be a precipitating factor in the development of both trigger points and joint pain and therefore must be addressed. Certain muscles respond to a given situation (e.g., pain, impaired afferentiation by a joint) with tightness and shortening, whereas others respond by inhibition and weakness. Muscle responses seem to follow some typical rules, thus development of tightness or weakness may be considered a systematic and characteristic deviation in the functional quality of these muscles. The result of this deviation is a general imbalance within the whole muscular system. With an imbalance, a change in the sequence of activation of the muscle in the movement pattern occurs. This can further spiral the patient into a continuous cycle of weakness, tightness, abnormal movement patterns, and pain. As tight muscles are thought to inhibit their antagonists, stretching these muscles indirectly helps to restore strength.
Changes in muscle function play an important role in many painful conditions of the motor system and constitute an integral part of postural defects in general. Postural adjustments are the body’s strategy to maintain the center of gravity of the total body. An increase in any one curve must be compensated by a proportionate increase or decrease in the other curves. Fine muscle coordination is needed to prevent damage to a joint, especially during fast movement. Thus, balanced muscle coordination may be the best protection of our osteoarticular system. Treatment consists of stretching the short musculature and strengthening the weak muscles. Normal posture is sought, resulting in normal bony alignment and normalized stresses across the joints. Restoration of normal muscle balance results in the following:
Decreased repetitive microtrauma through normalization of biomechanical forces
Normalization of reciprocal action muscles
Restoration of normal flexibility (normal range of motion)
Passive stretching exercise is used in the treatment of trigger points (TPs). An active TP is associated with spontaneous pain at rest or with motion that stretches or overloads the muscle. Specific to a TP is referred pain and the “jump sign.” The pattern of referred pain from TPs and associated phenomena is relatively constant and predictable and does not follow a dermatomal pattern or nerve root distribution. TPs and their referral patterns are described in detail in the classic works by Travell and Simons. Passive stretching is combined with spray-and-stretch techniques, which employ a vapocoolant spray and stretching of the involved muscle to render the TPs inactive. The spraying is thought to reduce the painfulness of the stretch tension by blocking reflex muscle spasm initiated by autogenous stretch reflexes.
b) Strengthening exercise
Directly increasing muscle strength is achieved by high-intensity, short-duration exercise. Neuronal adaptation occurs first by increased efficiency to recruit motor neurons, followed by an increase in myofibrillar protein after about 6 weeks of exercise. Increased muscle strength helps patients perform functional tasks such as lifting and carrying. It may also be helpful in decreasing pain perception. Increasing strength has been shown to decrease pain in patients with back and neck pain.
c) Endurance exercise
Endurance exercise involves two types of exercise:
Exercise for whole body endurance
Exercise for specific muscle endurance
Whole body exercise is targeted to increase the patients’ maximal aerobic power or cardiovascular capacity by exercising them at 65% to 80% of their maximal heart rate, usually by treadmill walking, biking, or any form of dynamic exercise of large muscle groups. Work and functional tasks such as walking, climbing stairs, repetitive lifting, fighting fires, carrying loads, scaling walls, and running (necessary, e.g., for police or fire-fighting work) have a significant aerobic endurance component. Many tasks are defined by their energy cost as expressed in oxygen consumption or metabolic equivalents (METS). Patients need to have a maximal aerobic power high enough to perform functional tasks (work) without excessive fatigue.
Low-intensity, long-duration exercise is targeted to increase the aerobic capacity of a specific muscle so that it can sustain contraction for prolonged periods of time without fatiguing. This improves neuromotor control and coordination and thus prevents injury to passive structures during prolonged activities. Physical forces provide important stimuli to tissues for the development and maintenance of homeostasis. Endurance exercise of specific muscles is associated not only with increased capillary density of that muscle but also with increased strength of muscle, bone, and tendons. It results in thicker, stronger ligaments that maintain their compliance and flexibility and that are stronger at the bone–ligament–bone complex. This type of treatment is thus essential in the management of sprains and strains of ligaments, and of tendonitis.
Synovial fluid lubricates the ligamentous structures of joints and provides nourishment to cartilage, menisci, and ligaments. Repetitious motion enhances this transsynovial nutrient flow. In the spine, the health of the joints is largely dependent on repeated lowstress movements. The intervertebral joints and the facet joints require movement for the proper transfer of fluid and nutrients across the joint surfaces. In the same way, the intervertebral disc is largely dependent on movement for its nutrition. Endurance exercise thus improves the body’s ability to withstand repetitive physical forces and muscle fatigue. As most functional tasks are repetitive in nature, most patients have a greater need of increased endurance than of increased strength. Lack of trunk muscle endurance plays an important role in chronic back pain. Jette and Jette (1996) showed that endurance exercise is associated with better outcomes in the treatment of patients with chronic back pain. Guidelines for the treatment of chronic back pain advocate the use of exercise and the avoidance of passive modalities.
Aerobic exercise is thought to have beneficial effects on pain perception and mood. It appears that pain inhibition through exercise can be mediated through the opioid and the nonopioid systems. Analgesic effects of exercise have been found at submaximal workloads of around 63% of maximum oxygen consumption (VO2max). Rhythmic exercise stimulates the A-d or group III afferents arising from muscle. Histologically, A-d or group III afferents are a prominent group of fine myelinated fibers located in skeletal muscle nerves. Recent investigations indicate that these afferents respond to muscle stretch and contraction with low frequency discharge. For this reason, Kniffeki et al. called the endings of these afferents “ergoreceptors”. Thoren et al. and Lundeberg hypothesize that rhythmic exercise activates the ergoreceptors, which then activate the descending pain modulating systems.
Moderate aerobic exercise has been shown to be effective in the treatment of mild to moderate forms of depression and anxiety, which can be a powerful aid in the treatment of patients with chronic pain. Exercise in general should be focused on regaining physical functioning. For that reason, exercises should imitate functional movements. Weightbearing exercise helps reduce osteoporosis and is the treatment of choice in chronic complex regional pain syndrome (CRPS). Patients with CRPS are loath to use their affected body segment since any light touch stimulus causes dramatic pain. A hand or a foot held in a protective posture and not put to any use will exhibit shortened muscles and tendons (e.g., foot plantar flexion and inversion). Functional activities are initiated, often beginning with reflexively provoked action, such as catching or kicking a ball, or catching one’s balance after perturbation. Functional progress is made through gait training using a mirror to promote symmetrical motion, or correcting improperly used muscles, restoring normal muscle length and postural alignment, and working on strength and endurance to balance muscle groups around major joints. Treatment can be made more tolerable with the assistance of lumbar sympathetic blocks if there is sympathetic mediation of pain present.
(ii) Passive modalities and physical agents
Physical agents commonly used in physical therapy are electrical stimulation ranging from low-volt to high-volt, ultrasound, heat, and cold.
Electrical stimulation is most commonly used for reduction of pain, edema, and muscle spasm, and stimulation of muscle contraction. For each type of neural tissue, there is an optimal frequency at which the maximal response is elicited: 0 to 5 Hz for sympathetic nerves, 10 to 150 Hz for parasympathetic nerves, and 10 to 50 Hz for motor nerves. Iontophoresis involves the transmission of medication through the skin by means of electrical stimulation. Commonly used medications are lidocaine and dexamethasone for the treatment of pain and local inflammation such as occurs in any kind of tendonitis. Transcutaneous electrical nerve stimulation (TENS) was developed on the basis of gate control theory by Melzack and Wall. High-frequency stimulation is thought to stimulate Ab fibers, “closing the gate,” whereas low frequency stimulation is thought to activate the pain-inhibiting descending pathways. TENS, both high and low frequency, was shown to reduce pain and improve range of motion in patients with chronic back pain.
Ultrasound a form of mechanotherapy, has both thermal and nonthermal effects. The thermal effects include increased blood flow, increased extensibility of collagenous tissues, and decreased pain and muscle spasm. The nonthermal effects of ultrasound include cavitation and microstreaming, which results in mast cell degranulation, altered cell membrane function, increased levels of intracellular calcium, and stimulation of fibroblast activity. This results in an increase in protein synthesis, vascular permeability, angiogenesis, and the tensile strength of collagen. Ultrasound, therefore, may be beneficial when a limitation in range of motion is caused by contractures of ligamentous or capsular tissues, or to accelerate inflammatory processes, thus decreasing associated edema with subsequent pain relief and wound healing.
Local heat causes vasodilatation and local erythema, decreased fast fiber sensation, and, with prolonged exposure, decreased slow nerve fiber sensation. The electrical resistance of the skin is reduced as well. Superficial heat is used to increase circulation, reduce pain, and promote relaxation.
Local cooling produces an intense vasoconstriction followed by periods of vasodilatation. Prolonged cooling decreases nerve fiber conduction. Cold is used in acute injuries to decrease swelling and pain, in chronic forms of musculoskeletal pain for pain relief, and in spastic muscle to reduce muscle tone. From clinical observation, most patients with neuropathic pain have difficulty tolerating cold and report that it increases their pain.
Joint mobilization is a technique used to improve joint mobility when the ligamentous and capsular structures limit passive range of motion. A variety of pathologic mechanisms can be involved in joint contracture development: immobilization, joint trauma, sepsis, degenerative processes, and a variety of disturbances that result in mechanical incongruity of the joint surfaces. A lesion of the capsule gives rise to limitation of capsular mobility, which limits the patient’s active and passive range of motion and causes pain with movement. Treatment is directed to restoration of normal capsular mobility and thus normal range of motion. Joint mobilization can restore normal capsular extensibility by applying carefully directed forces across the articular surfaces. All collagenous tissues rely heavily on movement to ensure adequate nutrition, and they respond to loading much as bone does, according to Wolff’s law. When not stretching the tissues, joint mobilization can be used to decrease pain by stimulation of types I and II mechanoreceptors. Joint mobilization is usually combined with ultrasound or heat, as this is thought to make the tissue more extensible and treatment thus more effective. Several studies have pointed out the immediate or short-term symptomatic reduction of pain after spinal manipulation or mobilization in patients with low back pain of less than a month’s duration. Long-term results, however, were comparable for both the experimental and control groups in most studies.
Soft-tissue mobilization includes massage, passive stretching, and myofascial techniques such as myofascial release and craniosacral therapy. Massage can provide symptomatic relief of pain by increasing local circulation and stimulating Ab fibers. TP massage in combination with passive stretching is thought to inhibit TPs in muscle, thus reducing muscle pain. A special form of massage, called “desensitization,” includes techniques such as tapping, stroking, and massaging the skin and is used in the treatment of patients with CRPS to increase their tolerance of touch to the allodynic area. Patients are instructed to wear gloves or socks with progressively rougher inside surfaces (hair shirt analogy!) in addition.
III. PATIENTS WITH CHRONIC PAIN
Treating patients with nonmalignant chronic pain is a challenge that is ideally accomplished in a team format. These patients often present with pain complaints that seem out of proportion to objective findings, and they are completely disabled due to their pain, often in their work life as well as in their social and recreational lives. Patients with chronic pain usually present with primary as well as secondary impairments.
The primary impairments are the result of the original injury and may or may not be treatable by physical therapy. The secondary impairments are the consequence of the patients’ response to the initial injury with self-immobilization. Lack of exercise, poor body alignment, shortening and weakening of the joint structures, and overguarding of the injured part of the body result in a weakened physical condition that can make normal daily activities more difficult, uncomfortable, and stressful. As a result, pain and suffering increase. These patients are commonly depressed as well, thus further spiraling into a cycle of disuse, pain, and impairment. The impairments resulting from disuse are readily addressed by an aggressive exercise program composed of stretching, cardiovascular conditioning, strength and endurance training, and behavioral modification tailored to the patient’s individual needs.
Behavioral modification approaches are an important part of treatment and include ignoring pain behavior, education on the “hurt not harm” principle, and quota-based exercise. Patients areoften afraid they will harm themselves as they get more active. To address this, a quota-based exercise approach is used. The patient is made to progress systematically, thus learning that increased activity does not equal increase in pain. Strong emphasis is placed on self-management techniques of pain, as chronic pain is a long-term condition that patients need to be able to manage on their own.
Although exercise programs are tailored to patients’ individual needs, they commonly include the following:
Aerobic exercise: such as bike or treadmill, at 65% to 80% of predicted maximal heart rate
Stretching exercises for shortened musculature
Endurance exercise for the major postural muscles
Mobilizing exercise, if needed
Physical therapy goals for these patients are to increase function, decrease disability, establish effective pain coping and management skills, and decrease health care utilization in the long term. To achieve these goals, it is best that the physical therapist works within a team, including behavioral therapists, occupational therapists, social workers, and physicians. More detailed information on the treatment of patients with chronic pain can be found in Chapter 19.
The key to the success of physical therapy in the treatment of pain is the incorporation of physical therapy into a comprehensive treatment plan. Although physical therapy helps to restore function, the therapy may be less effective if the pain is not optimally controlled by medical or interventional treatment (thus impeding any improvement in physical function). Equally, attention to psychological well-being is important, since physical therapy may not be successful if the patient approaches it with a negative state of mind or in a state of severe depression. Physical therapy is a vital component of multimodal pain management, and the physical therapist is an important members of the pain team.
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