Physical Modalities: Adjunctive Treatments to Reduce Pain and Maximize Function

CHAPTER 44 PHYSICAL MODALITIES


Adjunctive Treatments to Reduce Pain and Maximize function



Bryan J. O’Young, MD, Mark A. Young, MD, Jeffrey S. Meyers, MD, Steven A. Stiens, MD




1. What is the role of physical modalities in pain management?


Physical modalities for the relief of pain are an important aspect of pain management and a time-honored adjunct of medical and interventional pain management. These modalities often serve to supplement and enhance interventional and pharmacological interventions. Physical modalities refer to any therapeutic medium that uses the transmission of energy to or through the patient. Physical forces such as heat, cold, pressure, water, light, sound, or electricity can be used as adjunctive treatment for the purpose of decreasing pain. In general, physical modalities are not meant to replace medical or other interventions; rather, they are intended to enhance overall outcomes.



2. Give specific examples of physical modalities employed in the clinical setting


Physical modalities that are employed in the clinical setting include hot packs (hydrocollator packs), cold packs, laser, therapeutic ultrasound, whirlpool, paraffin, electrical stimulation, traction/compression, massage and iontophoresis. These modalities produce effects including heating, cooling, movement, and analgesia. Heating and cooling agents are the most commonly used modalities.



HEAT



3. List the common indications for prescribing and administering mild to moderate heat therapy




image Muscle spasm, tension myalgia: Heat therapy allows muscle relaxation by reducing muscle tension.


image Pain: Heat therapy relieves pain by decreasing pain receptor sensitivity.


image Contracture: Heat therapy increases range of motion by increasing collagen extensibility.


image Hematoma, superficial abscess, thrombophlebitis: Heat therapy improves blood flow and circulation.



4. What are the precautions for therapeutic heat?


The following precautions should be addressed when considering therapeutic heat:



image Pregnancy: Avoid applying heat to the abdomen or low back; avoid immersing patient into a warm/hot whirlpool.


image Impaired circulation: Use milder superficial heat in areas with poor circulation, particularly in older and younger patients. Patient may have poor vasodilatory responses and therefore may get burned.


image Edema: Application to an edematous extremity in a dependent position has been shown to increase edema. Heat may be applied with caution with the area elevated if edema is present and is thought to be secondary to poor venous circulation.


image Cardiac insufficiency: Monitor the patient carefully because heat can cause both localized and generalized vasodilatation.


image Metal in area: Metal has a higher thermal conductivity and higher specific heat and can become very hot with the application of heat.


image Open wound: Avoid paraffin over an open wound as it may contaminate the wound. The loss of epidermis reduces the insulation of subcutaneous tissues and therefore the application of heat should be provided with caution and at a lower temperature. Check frequently for signs of burning.


image Over areas where topical counterirritants have been recently applied: Topical counterirritants can cause local superficial vasodilatation. If a thermal agent is further applied, the vessels in the area may not be able to further vasodilate to dissipate the heat and a burn can result.



5. Are there specific contraindications for therapeutic heat? (can I get “burned”?)




image Acute trauma, or inflammation: Heat can increase tissue temperature leading to increased vasodilation, which in turn may lead to increased blood flow that can aggravate the injury, increase pain, and delay recovery.


image Hemorrhage, bleeding disorders: Heat can increase blood flow, which can restart or exacerbate the bleed.


image Thrombophlebitis: Increase in temperature can increase risk of a thrombus becoming dislodged and moving to a vital organ.


image Decreased sensation: Reduced ability to sense the heat increases the chance of the patient being burned.


image Communication, alertness or judgment limitations that limit the patient’s response to pain: Inability to communicate the pain increases the risk of being burned.


image Malignancy: Avoid thermotherapy over or near malignant tissue; it may increase the growth rate or rate of metastasis.



6. What is the therapeutic range and duration of heat?


The therapeutic temperature range is 40-45° C and the duration is 5 to 30 minutes. Sustained temperatures of 45° or more can cause tissue damage and burns.



7. Are heating modalities only “skin deep”?


Some heating modalities, such as heat lamps, hot packs, hot-water soaks, and paraffin baths, are superficial and heat just the skin and the underlying subcutaneous tissue. Superficial heat is considered to be 1 to 2 cm. Other heating modalities are deep heating (diathermies) and are able to transmit energy through tissue and heat at depths of 3.5 to 8 cm, allowing treatment of joints like the hip.



8. How is dosing and intensity of heat determined in the treatment of patients with physical modalities?


All energy applications must be applied in a given dose with a particular rate of transmission and a given therapeutic goal. A patient’s sensory function at the site is the primary mechanism to judge safe application. The maximal therapeutic effect of heat in well perfused body tissues such as muscle, tendon, or ligaments is 42° C. This is normally expected to be uncomfortable for the patient with normal sensation. Sustained temperatures of 45° or more can cause tissue damage and burns. Cooling temperatures to 13° are uncomfortable but tolerated at the skin surface.



9. Name four primary modes of heat transfer and provide some examples of each




image Conduction: Heat transfer by direct contact (e.g., hot packs, paraffin baths)


image Convection: Heat transfer by circulation of a medium of a different temperature (e.g., fluidotherapy, whirlpool)


image Conversion: Nonthermal energy converts to heat (e.g., ultrasound, shortwave diathermy)


image Radiation: Exchange of energy directly without an intervening medium (e.g., infrared lamp)



CONDUCTION



10. What are hot packs, and what role do hot packs play in pain management?


Hot packs consist of canvas bags filled with a hydrophilic silicon gel that can absorb many times its weight in water. The packs are hung in racks inside a thermostatically controlled water cabinet that stays on at all times and ensures that the packs are kept at approximately 70-75° C. During use, the packs are removed from the water baths and excess water is drained. The packs are then wrapped in six to eight layers of dry towels. Hot pack covers come in various sizes to match the hot packs and each cover can substitute for two to three layers of the towels. Packs can maintain therapeutically useful temperatures for 20 to 30 minutes.



11. What are paraffin baths and what is their role in pain management?


Paraffin baths are a form of thermotherapy commonly used for treating conditions including contractures, scleroderma, and rheumatoid arthritis. A mixture of paraffin and mineral oil in a 7-to-1 ratio is placed in a container and is kept at 45-50° C. Paraffin baths are effective for treating distal extremities, which benefit from a medium that can easily shape to the contour of an area. This is done by dipping the area in the bath and then removing it so the wax can harden between each dipping. Alternatively, the area can be submerged in the bath for 20 minutes for more intense heating. Paraffin can also be used to treat the knees, back, and other areas by “painting” it over the areas.



CONVECTION



12. What is hydrotherapy?


Hydrotherapy involves the application of water either externally or internally for treatment of dysfunction. Local immersion techniques include whirlpool, and contrast baths. Full-body immersion techniques include Hubbard tank whirlpool and water exercise in pools. Nonimmersion techniques include local irrigation devices.



13. What are general indications for hydrotherapy?


Hydrotherapy is used for pain control, wound care, superficial heating and cooling, control of edema, and water exercise.



14. How is hydrotherapy used in pain control?


Although data is lacking, it is believed that the sensory stimulation from water to the peripheral mechanoreceptors gates the transmission of pain sensations at the spinal cord level. The decreased weight bearing in water immersion techniques and the reduction of inflammation from cold submersion may also play a role.



CONVERSION



15. What is therapeutic ultrasound?

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Jun 14, 2016 | Posted by in PAIN MEDICINE | Comments Off on Physical Modalities: Adjunctive Treatments to Reduce Pain and Maximize Function

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