Therapeutic Intervention Quiz 4 Review - Weeks 9-12

Cryotherapy: Physical Principles

• Cryotherapy involves using cold modalities for therapeutic purposes.
• It lowers tissue temperature to minimize bleeding and acute inflammation.
• Cold can be applied through cold packs, ice massage, cold baths, compression devices, hypercooled air, and vapocoolant sprays.
• Avoid cold exposure in individuals with cold hypersensitivity, impaired circulation, diminished sensation or high blood pressure.
• Cooling happens by removing heat, rather than adding cold.

Conduction

• Cooling occurs via conduction when heat transfers from a warmer area to a cooler area through direct contact of molecules.
• Commonly used conductive cooling methods include ice or cold packs and cold water immersion.
• A greater temperature difference between the skin and cooling source results in a greater tissue temperature change.

Convection

• With convection, there is direct contact between the skin and moving fluid particles.
• A cold whirlpool is a principal method of using convection in cryotherapy, where water moves over the patient’s skin as they move their body part within the water.
• Heat removal occurs faster with convection versus conduction due to the continuous introduction of cooler molecules to the skin.
• Water's specific heat results in 25 times greater heat loss than in air at a given temperature.

Evaporation

• Vapocoolant sprays use evaporation as a means of energy transfer.
• As the liquid evaporates, it cools and extracts heat upon contact with the skin.
• This creates a counterirritant stimulus, which reduces motor neuron activity and allows for easier tissue stretching.
• Skin temperature can drop quickly, but changes in subcutaneous tissue and muscle temperatures are small.

Factors Influencing Response

• Key factors include the temperature difference, exposure time, and thermal conductivity.
• Thermal conductivity measures a material's efficiency in conducting heat.
• Metals are better heat conductors than plastics.
• Tissues with high water content have higher thermal conductivity than adipose tissue.
• Adipose tissue acts as an insulator, resisting heat transfer.
• It takes longer to cool muscle tissue through adipose tissue.
• Other factors include the type and size of cooling agent, total body surface area, and activity level.

Heat Exchange

• Heat exchange occurs between an artery and a vein.
• The artery vasodilates and carries warm blood following heating, while vasoconstriction occurs with ice application.
• Cold causes vasoconstriction of arteries, decreasing the amount of warm blood flowing into the area.
• This reduces countercurrent heat exchange, slowing the warming of the area.

Biophysical Principles of Tissue Cooling

• Ice therapy lowers tissue temperature for swelling and pain control.
• Changes in skin temperature happen rapidly. Lowering the skin temperature surface temperature to 56.5 degrees is sufficient to produce a local analgesic effect.
• Lowering the skin temperature to 50°F can reduce nerve conduction velocity by 33%.
• Deeper tissues require longer cold application to lower the temperature.
• Adding cold modality after surgery can prevent a rise in intra-articular temperature, which can often lead to swelling and pain.

Physiological Changes from Reduced Tissue Temperature (Hemodynamic Effects)

• Cold decreases histamine and bradykinin, causing vasoconstriction.
• It increases smooth muscle tone, reducing bleeding.
• Cold increases blood viscosity and decreases blood flow.
• Reduction in skeletal muscle spasm can occur due to decreased pain and muscle spindle sensitivity.
• Short-duration cold can temporarily enhance muscle performance, but longer durations reverse this effect.
• Cold can decrease pain and joint inflammation in inflammatory conditions, but may also cause joint stiffness.
• Cold increases tissue viscosity and decreases elasticity, increasing resistance to motion.

Posttraumatic Edema and Inflammation

• Cold is typically the modality of choice for the first 24-48 hours after injury.
• It reduces fluid filtration into interstitial tissue due to vasoconstriction and prevention of increased microvascular permeability.
• Inflammation and pain are reduced, and local metabolism decreases, reducing cellular energy demands.
• Immediate cooling can reduce secondary tissue damage.
• Moderate cooling can limit the extent of swelling, but intense or prolonged cold can increase swelling formation.

Peripheral Nerve Effects

• Cold increases the threshold for depolarization and slows nerve conduction velocity.
• Extreme cold can block nerve conduction.
• Decreased nerve conduction velocity in sensory nerves facilitates pain reduction.
• Caution should be observed when cold supplied in the area of nerve tissue because of the risk of nerve injury or damage.
• Reduced motor ability should be considered if a patient will engage in physical activity after cold application.

Muscle Performance Effects

• Cooling agents can affect a muscle's ability to generate tension.
• As cold exposure lengthens, muscle temperature and strength decrease.
• Cooling for 10 minutes or longer requires caution before strenuous exercise.
• Muscle force generation assessments should be performed before or several hours after cold modality use for accurate results.
• Ice therapy can affect proprioception, hindering the ability to perform functional activities safely and efficiently.

Neuromuscular Effects

• Cold decreases deep tendon reflexes, frequency of clonus, and spasticity.
• Reduced gamma activity reduces spasticity.
• Local or regional cooling can benefit individuals with some neurological conditions.
• Cold is not appropriate for all individuals with a neurological condition because many individuals with spasticity report a worsening of symptoms when they become cold.

Cryotherapy: Indications, Guidelines, Contraindications

• R.I.C.E.: Rest, ice, compression, elevation,
• P.R.I.C.E.S.: Protection, rest, ice, compression, elevation, stabilization
• Goals of cold therapy are to reduce swelling and inflammation, prevent further injury, and return the patient to functional activities as soon as possible.
• It is imperative to apply cold as soon as possible after an injury occurs.
• Less intense cold applied for durations of 20-30 min, several times a day in conduction with elevation and compression appear to be a logical choice

Clinical Indications for Cold Therapy

• Cold therapy indications include acute musculoskeletal trauma and postsurgical pain and swelling.
• Cooling the skin can elevate a patient’s pain threshold and reduce pain.
• Most studies have shown no significant benefit for using cold to reduce DOMS.
• There’s little evidence supporting the effectiveness of cold therapy for migraines.

Guidelines for Cryotherapy

• Instruct patients on what sensations to expect (intense cold, burning, aching, numbness).
• Watch for signs of hypersensitivity, such as hives and wheals.
• If hypersensitivity is apparent, this should be documented and the cold treatment should be discontinued.
• Avoid stresses that could potentially reinjure or aggravate injury for 1-2 hours after treatment, because analgesia produced by the cold could mask exercise induced pain, giving patients a false sense of security..
• Generally, conductive cooling lasts 20-30 minutes.
• Intermittent cold applications are suggested to avoid adverse responses to nerves or blood vessels.
• Cardiovascular exercise before ice bag application will allow more rapid cooling of the muscular tissue due to increased blood flow that aids in the removal of heat from the cooled areas.

Selecting a Cooling Agent

• Decision factors include accessibility, the body part, need for compression/elevation, and area size.
• For small areas, ice massage can be effective.
• For distal extremities, a cool bath will efficiently cover all surfaces.
• If there’s a concern about swelling in the distal extremities, a cold compression device may be most appropriate
• Ice in a plastic bag provides superior cooling compared to commercial gel packs.
• Cold is usually the appropriate choice in an acute phase of an injury.
• Muscle spasms may respond to both heat or cold.

Contraindications for Cryotherapy

• Contraindications include cold urticaria, cold intolerance, paroxysmal cold hemoglobinuria, cryoglobulinemia, and Raynaud's disease.
• Do not apply over a regenerating peripheral nerve, an area of circulatory compromise, or peripheral vascular disease.
• Vasoconstructive effect of cold potentially compromise an already nutritionally deprived area.

Precautions for Cryotherapy

• Precautions are needed for individuals with hypertension, thermoregulatory disorders, or sensory deficits.
• Decreasing the duration and intensity of the cold may produce the desired effects without eliciting adverse reactions.
• Prolonged cold application should be avoided over a superficial peripheral nerve.
• Avoid vigorous cold application directly over a wound during the initial two to three week period of healing.

Cryotherapy: Methods and Assessment

• Common methods include homemade ice bags/cold packs, ice/cold baths, commercial cold packs, and cold compression units.

Cold Packs

• Cold packs are convenient, economical, and portable.
• It is generally recommended that the size of the cold pack should correspond to the area, to be treated, or the size of the area to be treated
• Pack contents include ice plus water, water plus alcohol, gel, or chemicals.
• Use towels around the skin for any agent that can reach temperatures below 30 degrees Fahrenheit. Damp towels are superior to dry ones.
• Ice is the most effective type of cold, because it has to undergo a phase change from solid to liquid, which causes greater heat extraction when no phase change is required
• Commercial gel packs require a layer of damp towels and are not as effective as ice packs.
• The mixture of water an isopropyl alcohol can also be used as a homemade cold pack

Ice Massage

• Ice massage is performed over a small area or trigger points.
• Slowly rub ice on the skin using small, overlapping circles.
• Patients experience cold, burning, aching, and analgesia.
• Skin temperature usually will not drop below 59 degrees Fahrenheit with continuous movement of ice.

Vapocoolant Spray

• Use vapocoolant spray to treat trigger points and induce relaxation before stretching.
• Repeated treatments during the same session are done only after the skin has returned to normal temperature to avoid frost biting the area or the skin.

Manual and Electric Cold Compression Units

• Manual units allow manual circulation of cold water through a cuff.
• Electric units use a pump for continuous cold water circulation.
• Compression is achieved by the pressure exerted from the fluid filled cuff wrapped around the joint.
• Studies investigated the differences in post operative outcomes comparing continuous cold compression units to traditional icing protocols.
• Pain, swelling, range of motion and medication were improved to a greater extent in patients who used continuous cold compression versus ice packs, which is why we commonly see these post-surgical

Cold Baths

• Use cold baths to cool distal extremities.
• Temperatures range from 50°F to 64.4°F.
• Increased water movement quickens cooling.

Cold Gel

• Cold gel contains chemicals like ethanol or methanol.
• Gels are easy to apply/transport and do not require refrigeration.

Assessment of Effectiveness

• Assess edema using girth measures/volumetrics.
• Evaluate pain using pain scales/questionnaires.
• Measure range of motion using goniometry.
• Assess functional movements via gait observation.
• Evaluate muscle guarding using joint ROM/muscle flexibility measures.

Therapeutic Heat: Physical and Biophysical Principles

• The greatest temperature elevation occurs in the skin and subcutaneous tissues within 2.5 cm of the skin surface.
• Muscle temperature at a depth of 1-2 cm increases to a lesser degree and requires longer exposure.
• Fat provides insulation and has a low thermal conductivity.

Heat Transfer

• With conduction, the kinetic motion of atoms and molecules of one object is passed to another object.
• Convection is the bulk of movement of moving molecules, either in liquid or gaseous form, such that the heat is transferred from one place to another
• Radiation involves converting heat energy to electromagnetic radiation.

Factors Influencing Response

• These include the extent of temperature increase, the rate of energy added, the volume of tissue exposed, tissue composition, and the tissue's capacity to dissipate heat.
• Tissue temperature must be elevated to between 104 and 113 degrees Fahrenheit.

Biophysical Effects of Temperature Elevation

• Tissue needs to be elevated to 104-113°F for a therapeutic effect.
• Increased cell activity and metabolic rate occur.
• There is increased oxygen uptake by tissues.
• Mild temperature increases shift the oxygen-hemoglobin association curve, improving oxygen availability.
• Temperatures above 113-122°F can cause tissue burns due to protein denaturation.
• Vasodilation occurs, increasing blood flow; reflex vasodilation can occur in areas remote to the site of application.
• Skeletal muscle blood flow is primarily under metabolic regulation, expect minimal change through use of heating modalities.

Neuromuscular Effects

• Heat provides pain relief and assists in resolving muscle guarding/spasms.
• It elevates the pain threshold, alters nerve conduction velocity, and changes muscle spindle firing.
• Temperature elevation can temporarily change the ability to build muscle tension.
• Heat reduces gamma afferent activity and sensory nerve action potential latencies, therefore, stretch is reduced on the muscle spindle.

Connective Tissue Effects

• Heat increases elasticity and decreases viscosity/joint stiffness.
• Lower loads of longer duration result in less tissue damage and greater increases in joint range of motion.
• Heating increases muscle flexibility and facilitates ease of motion.
• Plastic elongation can happen through heat and stretch, considering temperature elevation, site, time, amount and stretch.
• Greater residual length changes occur when stretch is applied during the time the tissue is elevated to the therapeutic levels between 104-113 degrees Fahrenheit

Therapeutic Heat: Indications, Guidelines, Contraindications

• Clinical indications include reduced pain/stiffness, decreased muscle spasm, increased ROM, and improved tissue healing.
• Tissue should be elevated to 104-113°F during a 15-30 minute intervention.

Guidelines for Therapeutic Heat

• Determine patient circulation and sensitivity to temperature/pain beforehand.
• Test thermal sensation using hot/cold water and pinprick versus blunt tests.

Contraindications for Therapeutic Heat

• Contraindications include lack of intact thermal sensation, vascular insufficiency/disease, recent or potential hemorrhage, known malignancy, and acute inflammation.
• Do not use with infection, liniments/heat rubs, or unreliability.

Therapeutic Heat: Methods and Assessment

• Thermal modality options to increase tissue temperature at 1-3 cm depth include moist heat packs, paraffin wax bath, fluidotherapy, warm whirlpool, microwavable gel packs, air-activated heat wraps.
• Thermal modality options to increase tissue temperature at 1-5 cm depth include continuous ultrasound, continuous shortwave diathermy.

Conductive Heat Modalities

• Conductive heat modalities depend on tissue thermal conductivity, exposed body volume, and exposure time.

Moist Heat Pack or Hot Packs

• Moist heat packs are canvas or nylon cases filled with a hydrophilic silicate or sand.
• Store them in a thermostatically controlled cabinet at 158-167°F.
• Hot packs should be appropriate size totally cover the intervention area and secured in place but not so tightly that the patient cannot remove it if it becomes too hot.
• Cover packs in 6-8 layers of terry cloth toweling/hot pack covers.
• Monitor patients for overheating effects.
• Ensure the patient is not lying with their full body weight on the hot pack to avoid compressing vessels and overheating the skin.
• Inspect moist heat packs regularly for leaks.
• Advantages: ease of use, various sizes, moist heat, inexpensive.
• Disadvantages: no temperature control, does not conform, heat does not last long, passive intervention.

Paraffin Wax

• Paraffin wax has a low melting point of 129°F, with the ability to lower by adding paraffin oil or mineral oil.
• It evenly distributes around the treated part due to its molten state.
• It is useful for distal extremities because of the low specific heat.
• A usual mixture of about six or seven parts paraffin wax to one part oil.
• Dip and wrap involves dipping then wrapping the treated area; dip and re-immerse technique requires immersion.
• It can be applied over healed skin grafts 10 days post-graft.
• It is not significantly better than other modalities at reducing pain/increasing joint ROM.
• Advantages: molten state, traps air, oil moisturizes, stays malleable, provides heat, inexpensive, low heat.
• Disadvantages: use limited to extremities, no temperature control, heat lasts 20 minutes, patient unable to exercise simultaneously.

Electric Heating Pad

• Electric heating pads can apply low-level heat over a long period.
• Has an adjustable intensity control and readily available for purchase and reasonable cost.
• Disadvantages: requires outlet, can cause burns, patients cannot perform activities
• Patient must be near an electrical outlet/some pads heat up enough to produce superficial burns

Air-Activated, Wearable Heat Wraps

• These wraps are made of cloth embedded with discs of iron powder, activated charcoal, sodium chloride, and water.
• Maintaineds a temperature of about 104 degrees Fahrenheit.
• Heat is produced through an exothermic reaction.
• Has advantages of providing dry heat, maintains heat and allows for exercise
• A disadvantage of air activated wearables is that they are only for one use.

Fluidotherapy

• Fluidotherapy is a dry heat modality that transfers heat energy by forced convection.
• Uses air fluidized solids as the transfer medium for the heat.
• Use the tool to provide massaging action, sensory stimulation, and levitation.
• Temperatures for intervention usually range from 102 to 118 degrees Fahrenheit
• Temperature/particle agitation can be controlled.
• Heat transfer characteristics within the fluidized bed into parts submerged in it are similar to those of a mildly agitated liquid.
• If the treated area has an open wound, protect the wound with a plastic barrier to prevent particle embedding.
• Advantages: convenient/easy, agitation/temperature controlled, unit sizes vary, facilitates exercise/desensitization, provides dry and comfortable heat.
• Disadvantages: expensive, enclosed space, intolerance to materials.

Clinical Decision Making

• To use heat versus cold, consider the injury stage, the body area, medical status, and patient preference.
• Cold is usually preferred during acute inflammation.
• With respect to wet versus dry, consider if at home application.
• Provide clear instructions to prevent burns/excess heat.

Assessment of Effectiveness

• Assess pain using pain scales/questionnaires.
• Measure range of motion using goniometry
• Assess functional movements via gait observation.
• Evaluate muscle guarding using joint ROM/muscle flexibility.

Documentation

• Include the modality used, method of application, duration, body area, patient position, precautions, and patient response.

Light Therapy

• Light rehab includes UV light, light-emitting diode (LED), and laser.
• Laser stands for "light amplification by stimulated emission of radiation."
• Lasers are Class 3B (low power) or Class 4 (high intensity).

Physical Properties of Lasers

• Lasers have unique properties because of the technology used to create them, including a concentrated beam of light energy.
• Most common laser devices use semiconductor laser diodes.
• Laser light features coherence, monochromaticity, and directionality.
• All light waves are in phase with each other, meaning they oscillate at the same frequency and maintain a constant phase relationship, resulting in a highly focused and directional beam of light.
• The light produced is in a single wavelength
• Light beams can travel greater distance in a single direction with less divergence than sunlight or incandescent bulbs.
• Laser energy density is measured in Joules per cm squared.
• Laser dosimetry is often measured as total joules per treatment session or in joules per treatment point, or body surface area depending on the mode of application.

Physiological Effects of Lasers

• Lasers have been found to help with tissue repair and inflammation.
• Laser effects are associated with produced-light wavelengths.
• Cellular components absorb certain wavelengths of light energy.
• The mitochondrial chromophore stimulation increase the respiratory chain activity and enhance ATP synthesis.
• High intensity laser therapy was also reported to improve diabetic and neuropathic foot ulcers by increasing blood flow.
• Infrared was reported to increase vasodilation due to increased histamine and nitric acid levels Resulting in decreased tissue ischemia and increased perfusion.
• Low level laser has been shown to modulate various chemical mediators of pain, including a pain associated with inflammation.
• Infrared was reported to increase levels of beta endorphin, an endogenous opioid

Instrumentation and Clinical Application

• Low-level lasers are Class 3B, while high-intensity lasers are Class 4.
• Both categories require eye protection to prevent retinal damage.
• Laser techniques include direct skin contact or a grid pattern.
• Grid refers to the pattern of evenly spaced laser spots applied to a treatment area, creating a network resembling a grid.
• High-intensity light therapy dosages are usually much higher because of the high peak power capabilities.

Indications for the Use of Lasers

• Pain and inflammation occur with musculoskeletal conditions and chronic skin wounds.
• Both low level light therapy and high intensity laser therapy may be most effective in the treatment of patients with chronic myofascial trigger point conditions.
• Patients with uncomplicated mild to moderate carpal tunnel syndrome may also benefit from low light laser therapy.

Precautions for Light Therapy

• Take caution with impaired sensation or skin color.

Contraindications for Light Therapy

• Contraindications include direct eye exposure, pregnancy, hemorrhage, active malignancy, open growth plates and exposure to endocrine glands.
• Effects of light therapy during pregnancy are unknown.

Ultrasound – Physical Principles

• Ultrasound is a high frequency mechanical wave delivered using acoustic/sound energy.
• Commonly used for decreasing soft tissue inflammation and pain, for increasing tissue extensibility, scar tissue re-modeling, and healing acute soft tissue injuries.
• Gel helps transmit the vibration, because those molecules are going to be closer together.
• Compressions are areas of increased density of the molecules.
• Rarefactions are areas of decreased density.
• The longitudinal waves move away from the emitter in all directions or dispersion the sound energy can be focused or collimated to give a greater directionality.
• When the beam of energy reach a point of change in the tissue density, the waves can be reflected, refracted, or absorbed.
• When the wave is absorbed, the kinetic energy of the movement is transformed into thermal energy.
• Waves that pass through the denser tissue will be refracted or bent and will no longer follow that original path.
• Waves can be reflected. The angle of reflection is dependent on the angle of incidence at the interference between the tissues of different densities.
• In the body, the ultrasound waves are more rapidly attenuated and converted from acoustic or sound energy to thermal energy in dense tissue such as ligaments, tendons, and other connective tissues than in less dense muscle or even less dense adipose tissue.
• Higher tissue temperatures will result when the therapeutic ultrasound is applied to connective tissues than when applied to muscle and other less dense tissues.

Production of Ultrasound Waves

• The key components of an ultrasound device include an applicator and a generator.
• The applicator is composed of a piezoelectric crystal (made of lead zirconate or titanic ceramic) and a sound head (often aluminum, stainless steel, or ceramic).
• Piezoelectric crystal transversely compressed and expanded by sending an alternating current through it which refers to reverse piezoelectric effect.
• This rapid compression/expansion produces an acoustic wave which is transmitted to a sound head and then to the body/skin of the treatment area.
• The area of the crystal that moves is the effective radiating area (ERA).

Phonophoresis

• Phonophoresis refers to the application of US to enhance the absorption of topical agents through the skin.
• It is usually completed by applying the US directly to the topical agent or adding it to the gel.
• Phonophoresis cannot be recommended due to a lack of evidence.

Treatment Parameters – Frequency

• Frequency is the number of waves per second delivered to the patient (ranges from 0.75 to 3.3 MHz.
• Fewer frequencies penetrate deeper.
• Effective treatment depths are up to 6 cm with 1 MHz and up to 2.5 cm with 3 MHz.
• Higher frequencies penetrate more superficially and heat faster.
• The depth of penetration increases with decreasing frequency.

Treatment Parameters; Intensity and Dosage

• Power is measured in watts, but represented as spatial average intensity measured in watts per centimeter squared.
• The spatial average intensity is commonly and incorrectly described as power divided by the sound head area
• No definitive guidelines are available for an optimal intensity level as the variance in the ERA ultrasound applicators from different manufacturers can affect the treatment

Treatment Parameters – Mode

• Ultrasound can be delivered in continuous or pulsed modes.
• In pulsed ultrasound, there’s a period of time that there’s no ultrasound delivered
• With pulsed US, the total energy is reduced, and that temporal (time) average intensity is used.
• Continuous ultrasound is typical when heating is needed, pulsed ultrasound is typical when the energy level needs to be reduced to produce the non-thermal ultrasound

Other Principles of Therapeutic US

• Beam nonuniformity ratio (BNR) is the ratio of the spatial peak intensity measured anywhere within the effective radiating area.
• Units with a higher BNR are more likely to cause discomfort due to hot spots at areas of peak intensity.
• The sound head is moved continuously around the treatment area to equally distribute hot spots or prevent discomfort/burns.
• Apply ultrasound to an area two to four times the size of the ERA when using 1 MHz.

Variation in Treatments and Ultrasound Units

• Components of variation include treatment duration, treatment number/frequency, and ultrasound units.
• Treatment duration is dependent on the size of the area being treated, settings of the ultrasound unit Intensity.
• Clinician has to readjust the treatment protocols based on the specific unit, applicator, patient, and the condition being treated.

Variability in Application Medium

• Keep radiating waves perpendicular to skin.
• Maintain applicator contact with skin.
• Use a coupling medium between the US applicator and the skin.
• Continuously move the applicator face plate.
• Ultrasound gel serves as a lubricant for easy movement of the applicator over the skin, also having a 100% transmission of US waves.
• Water immersion can be used for irregular surfaces.

Moving the Sound Head

• Move head slowly over the skin at 3-4 cm per second
• It should be moving with overlapping circles, but there’s no significant differences in tissue heating between the movement of the US applicator at varying speeds.

Proper Application of US

• Treat the correct size area, select duration, adjust intensity and use the correct frequency.
• If combined with stretching, stretch during the last few minutes of US or immediately after heating.

Documentation Tips for US:

• Include the intensity, frequency, duty cycle, treatment duration, sound head size, treatment area, coupling agent, patient position, and patient response.

Tissue Response

• Greater and faster rises in temperature occur when applying US to tendons.
• A rapid cooling phase occurs immediately after US ends (lasts about 5 minutes).
• Immediately following the end of US, a rapid phase of cooling occurs, which lasts for about 5 minutes
• It is followed by a slower rate of cooling that lasts until the temperature of the tissues returns to normal.

Variability in Responders

• Reasons for variation include % body fat, tissue hydration, blood flow, metabolism and protein content.

Thermal Effects

• These involve increased collagen fiber extensibility, decreased joint stiffness/muscle spasm, pain modulation, increased blood flow, and a mild inflammatory response.
• These effects occur when the tissue reaches 40-45°C for at least 5 minutes.
• A tissue temperature increase of 1-degree Celsius increases metabolism and healing.
• 2 to 3 Celsius decreases pain and muscle spasm.
• Increases in 4 degrees Celsius or greater increases extensibility of the collagen and decrease of joint stiffness.
• Tissues high in collagen can be selectively heated without significantly raising the temperature of the skin/fat
• 3 MHz US will heat more superficial tissues, while 1 MHz will reach deeper tissues.

Non-Thermal Effects

• Cavitation is the formation of gas-filled bubbles that expand and compress due to pressure changes (stable and unstable).
• Stable cavitation provides therapeutic benefits.
• With acoustic streaming, there is unidirectional movement of fluids along cell membranes as well as change in membrane permeability in sodium and calcium ions which is important in the healing process.
• Non-thermal effects can be significant in soft tissue repair, fibroblast activity, blood flow, bone healing and immune response alteration.

Ultrasound – Evidence for Treatment

• Commonly stated for pain: MTrPs, back pain, nonspecific shoulder conditions; for inflammation: lateral epicondylitis; carpal tunnel syndrome; calcific tendinitis; bursitis; arthritis; for soft tissue and scars: healing of soft tissue, extensibility of tissue, remodeling of scar tissue, swelling from tissue

Recommended Protocols for Conditions with Substantiated Effect

• Myofascial pain: 1 MHz for 1-2 w/cm2 for 10 min three times a week
• Back pain/dysfunction: 1 MHz for 1-2 w/cm2 for 10 min three times a week
• Carpal tunnel: 1-3 MHz for 0.5-1.5 w/cm2 for >5 times per week for 2-4 weeks
• Calcific tendinitis: 1-3 MHz for 1-2 w/cm2 for 10 min three times a week for 4-8 weeks