Pain Management Modalities

Kernersville Rehab Specialists Aquatic Physical Therapy

Modalities are specialized therapeutic techniques, agents or devices often integrated into the comprehensive treatment program. Modalities utilize sound waves, heat, mechanical, electrical, and light energy to create changes in tissues for therapeutic purposes. They are described in greater detail below.

  • Modalities
  • Hot Packs/Heat Therapy
  • Cold Packs/Cryotherapy
  • Iontophoresis
  • Ultrasound
  • Phonophoresis
  • Electrical Stimulation
  • TENS
  • Interferential Stimulation
  • H-Wave
  • Low Level (Cold) Laser Therapy

Hot Packs/Heat Therapy

Heat therapy speeds up nerve impulses, possibly advantageous in conditions where nerve response has become slowed. It dilates blood vessels, enhancing local blood flow which improves delivery of oxygen and nutrients to tissues, and removes cellular waste from tissues. This helps speed the healing process. Heat also helps relax muscle tissue--decreasing stiffness and muscle spasms--which allows for greater range of motion. It may be used before stretching, passive range of motion or active exercises to maximize muscle action. It may be used prior to therapy such as myofascial release or joint mobilization, or simultaneously with several other modalities to maximize muscle relaxation. Heat is not used in treating an acute (new) injury.

Cold Packs/Cryotherapy

Cryotherapy therapy is often one of the first treatments applied to new injuries. Cold causes blood vessels to constrict (narrow). Vasoconstriction slows blood flow and leakage of fluid from capillaries into the surrounding tissue spaces. This reduces bruising, swelling, inflammation, muscle spasms and acute pain. In the clinic, cold therapy is often combined with compression therapy (using vasopneumatic equipment) to further reduce edema or swelling from fluid buildup in tissue spaces. Patients may also be instructed on the use of cryotherapy or ice massage at home between clinic visits. Cryotherapy also slows nerve impulses, which might help reduce or control overly sensitive or hyperactive nerve disorder activity.


This is a method of administering medication (such as anti-inflammatory or corticosteroid drugs, and local anesthetics) into tissues through the skin. These medications are delivered to a limited area--avoiding systemic side effects occurring when the drug is taken by mouth—to reduce swelling and pain from inflammation. To avoid the pain or potential trauma of injections, medication administered in this manner is applied to electrode pads (similar to those used when getting an EKG heart rhythm tracing). The pads are applied to the skin, then connected to a battery power source. Painlessly, the positive current drives the positively charged drug molecules from the pad into the tissues. In the same manner, the negative current drives the negatively charged drug molecules (such as dexamethasone) from the pad into the tissues. The pads are worn as directed by the therapist, usually for 12 to 24 hours. This same effect can be demonstrated by taking two magnets, and trying to place the positive poles together (or the negative poles together). They repel or push away from each other. Iontophoresis may be used treat conditions such as inflammation, tissue swelling, muscle spasms, muscle and joint pain, myositis, tendonitis, tendosynovitis, adhesive capsulitis, and bursitis.


The ultrasound device converts electrical current to high frequency sound waves, undetectable by the human ear. The sound waves penetrate deeply into muscle, nerve, bone and connective tissues. The waves vibrate the cells and cause friction, which creates heat. This occurs much deeper in the tissues (2 inches or more) than heat packs or any other heating modality can reach. The heat causes vasodilation with increased blood flow in the deeper tissues, which results in improved delivery of oxygen and nutrients as well as removal of cell wastes in these tissues. Deep heat also leads to decreased nerve sensitivity and pain by sedating nerve endings. Furthermore, it reduces swelling, inflammation, and muscle spasms as it increases range of motion, muscle relaxation, and tissue healing. Vibration helps to mechanically stretch collagen connective tissue cells to increase flexibility in tendons, ligaments, joint capsules, and even to soften adhesion and scar tissues to further help the healing process.

Ultrasound is usually used for treatment after the acute phase of injury or inflammation process. Ultrasound can be used to treat chronic inflammation, soft tissue injury, nerve root irritation, non-acute bursitis and adhesive capsulitis; it can help with tissue regeneration and softening of scar tissue. Ultrasound is often limited to 6-10 treatments per body area to prevent over-treatment effects, so it may be alternated or combined with other modalities (such as manual mobilization, stretching and therapeutic exercise), in the individualized therapy plan.


Phonophoresis is like a hybrid blending of ultrasound and iontophoresis. It uses ultrasound's high frequency sound waves to drive a medication into the tissues. A topical anti-inflammatory agent is blended into the ultrasound gel and applied to the skin over the treatment area. The ultrasound waves carry the medication into the tissues, reducing inflammation along with the therapeutic heat and vibratory effects. The most common conditions treated include inflammatory conditions such as arthritis, bursitis, and tendonitis.

Electrical Stimulation

Small electrodes (like those used on EKG/heart monitors) are applied to the skin in certain patterns. Low voltage current passes from the device to the electrodes and into the tissues at the treatment site. This produces a tingling sensation while stimulating the muscles and nerves in that area. The electrode patterns and electrical properties of the current (waveforms, pulse rates, cycles and duration) can be changed to produced the desired treatment characteristics.

Electrical stimulation therapy can be used for two primary functions in nerve tissue. First, when nerve tissue is stimulated, it can produce muscle contraction. This effect can be used to strengthen muscle tissue, or to maintain the strength of muscles to prevent muscle wasting when normal nerve function has been disrupted. Situations in which this disruption occurs include stroke, neurological disease, traumatic injury, or following surgery. Stimulation may also be used to help stop muscle spasm by overly fatiguing the muscle through repetitive contraction. Additionally, induced muscle contraction may help decrease swelling by pumping excess fluid from surrounding tissue spaces back into the vascular system for removal.

A second use of electrical stimulation is for altering perception of nerve impulses. The tingling sensation produced by electrical stimulation interferes with the pain signal reaching the brain to be perceived as pain. Depending on the nerves and therapy involved, these pain signals are either blocked outright, or are masked by the tingling sensation.

Electrical stimulation helps reduce pain, inflammation and swelling, and maintains muscle function. Additionally, it helps improve the wound and tissue healing process through increased blood flow which brings nutrients and removes wastes. Electricity also stimulates generation of new cells to repair injured ones.

There are various electrical stimulation devices, each with different therapeutic properties, used at Kernersville Rehab Specialists. The most common include:

  • Transcutaneous Electrical Nerve Stimulation (TENS)
  • Interferential stimulation
  • H-Wave

Transcutaneous Electrical Nerve Stimulation (TENS)

This portable electrical stimulation device is designed specifically for pain relief. The tiny electrical pulses delivered through the skin to sensory nerve fibers produce numbness or tingling sensations that "mask" or "override" sensations of pain. The impulses from the TENS fill the nerve pathways to the brain thereby preventing the transmission of pain signals to the brain. It also appears that TENS can activate peripheral nerve fibers that can block pain transmission at the spinal cord level. Electrical stimulation of these sensory nerves also causes release of natural pain relievers (opiates) within the body. It promotes improved blood flow which can help pain conditions associated with reduced flow or build up of wastes in tissues, as in trigger points.

These small, battery powered units can be worn while the patient continues activities. The therapist adjusts the unit's settings (amplitude, frequency, and pulse width) to deliver the desired therapeutic effects, and instructs the patient how and when to use the unit. The patient places the electrodes on the skin over the area of pain and uses the unit as directed by the therapist. Patients can use the unit at home, at work, or during activities when experiencing pain or spasm.

TENS units provide safe and effective pain relief for back pain, neck pain or "whiplash," sprains/strains/pain of the ankle, knee, hand, wrist, and rheumatoid arthritis. TENS may help with other acute and chronic pain conditions such as myofascial pain, trigger points, phantom limb pain, post-operative pain, and various pain-related neurological conditions. TENS units may be used as part of the patient's individualized comprehensive pain management program. KRS stocks these units so they may be made available immediately to patients when indicated.

Interferential Stimulation

Interferential stimulation is another type of electrical stimulation as described above, but more complex than the TENS device. It uses dual frequency stimulation, one a fixed frequency, the other being variable. The electrodes are placed such that these electrical waveforms create circuits which cross each other to produce maximum pain signal interference at the treatment target site. The cumulative interference effect of both frequencies may provide greater effects than can be achieved with a single frequency. Otherwise, the effects of therapy and the conditions treated are similar.


H-Wave is a unique electrotherapy device used to aid the rehabilitative process. The goal and function of H-Wave is vastly different from other devices. By focusing on fluid shifts, the physiologic foundation of recovery, H-Wave provides clinically significant outcomes. H-Wave is proven to be effective for reducing pain, muscle spasm, and muscle atrophy (weakness and wasting). Simultaneously, it improves circulation and range of motion.

As an electrical stimulation device, H-Wave works in two ways. First, comfortable rhythmic muscle contractions are created to pump blood (which delivers oxygen and nutrients) through the injured area to promote faster healing. At the same time, cellular wastes and the excess fluids that have leaked into the tissue spaces (causing swelling) as a result of injury are pumped out of the area. The removal of wastes and excess fluids takes the pressure off of nerves and allows more movement of joints; while the delivery of nutrients is vital to the body's recovery. These are the rehabilitative benefits of H-Wave. The second function of H-Wave is to directly stimulate and calm irritated nerves with a high frequency pain control signal. This mechanism provides cumulative relief for acute, post-operative and even the most difficult chronic pain, for significant and lasting pain control.

Published research has shown that the use of H-Wave can help reduce pain, reduce the need for pain medications, and improve function and the ability to complete activities of daily living. By helping to eliminate many of the obstacles to exercise and physical therapy, H-Wave can also help make therapy sessions more productive and effective.

Low Level (Cold) Laser Therapy

Low Level Laser Therapy (LLLT) is becoming a very popular, effective treatment for pain management in physical rehabilitation. This form of laser therapy is quite different from "hot" lasers that can be used to cut through skin (or even metal!) and destroy certain unwanted tissues. Those powerful lasers can emit as much as one million watts of energy. LLLT or "cold" lasers used in our office emit only a fraction of that amount of energy, usually around 10 milliwatts (one hundredth of one watt)—one hundred million times weaker. Instead of destroying tissue, the cold lasers actually help promote cellular regeneration or healing at an accelerated rate.

These lasers provide a non-invasive, painless, drug-free tool for effective pain management. Along with the reduced healing times, they also decrease inflammation and swelling. During laser therapy, there is usually no sensation at all, though some patients may feel a slight warmth or tingling sensation at the treatment site. Based on a specific wavelength and frequency, the energy transmitted to the cells from the laser's light beam initiates chemical reactions that enhance blood flow, cellular metabolism (delivery of needed oxygen and nutrients, removal of cellular wastes), cell growth, tissue repair, and reduce concentrations of prostaglandin E2. This involves various processes within the vascular, lymphatic, hematopoietic, lymph, and immune systems. Some of these beneficial effects may begin occurring immediately with treatment, others may take longer, depending on the severity of the condition being treated.

LLLT was initially approved by the FDA in 2002 for use in carpal tunnel therapy. In worldwide application since then, it has been found effective in treatment of most:

  • Acute and Chronic Pain Disorders
  • Inflammatory Conditions
  • Soft Tissue and Joint Injuries or Dysfunction
  • Nerve Injuries, Neurological Conditions
  • Repetitive Stress Trauma (Carpal Tunnel Syndrome)
  • Fibromyalgia