Therapeutic Modalities Therapeutic Modalities ReviewReview

Basic Principles of Electricity

and Electrical Stimulating Currents

Electrotherapeutic Currents•Direct (DC) or Monophasic

–Flow of electrons always in same direction

–Sometimes called galvanic

Electrotherapeutic Current•Alternating (AC) or Biphasic

–Flow of electrons changes direction

•Always flows from negative to positive pole until polarity is reversed

Electrotherapeutic Currents•Pulsatile Current

–Pulses grouped together and interrupted

•Russian and interferential currents

–May be bi-directional or uni-directional

Electrical Generators•All are transcutaneous electrical stimulators

–Transcutaneous electrical nerve stimulators (TENS)

–Neuromuscular electrical stimulator (NMES) = Electrical muscle stimulator (EMS)

–Microcurrent electrical nerve stimulators (MENS) = Low intensity stimulators (LIS)

Pulse Frequency (CPS, PPS, Hz) •Number of pulses or cycles per second

•Muscle and nervous tissue respond depending on the length of time between pulses and on how pulses or waveforms are modulated

•Low vs. Medium vs. High frequency currents

Electrode Placement

•Electrodes may be placed:

–On or around the painful area

–Over specific dermatomes, myotomes, or sclerotomes that correspond to the painful area

–Close to spinal cord segment that innervates an area that is painful

–Over sites where peripheral nerves that innervate the painful area becomes superficial and can be easily stimulated

–Over superficial vascular structures

–Over trigger point locations

–Over acupuncture points

–In a crisscrossed pattern around the point to be stimulated so the area to be treated is central to the location of the electrodes

–Bipolar application resulting in similar physiologic effects beneath each electrode

–Monopolar setup both an active and dispersive pad set up causing higher current density at the active electrode

–Quadripolar technique

Physiologic Response To Electrical Current•Electricity can have an effect on each cell and tissue it passes through

–Type and extent is dependent on the type of tissue, its response characteristics, and the nature of current applied

•Reactions can be:

–Thermal

–Chemical

–Physiologic

•Can be used to:

–Creating muscle contraction through nerve or muscle stimulation

–Stimulating sensory nerves to help in treating pain

–Creating an electrical field in biologic tissues to stimulate or alter the healing process

–Creating an electrical field on the skin surface to drive ions beneficial to the healing process into or through the skin

Therapeutic Uses of Electrically Induced Muscle Contraction – High-volt Currents•Muscle re-education

•Muscle pump contractions

•Retardation of atrophy

•Muscle strengthening

•Increasing range of motion

•Reducing Edema

Muscle Re-Education•Muscular inhibition after surgery or injury is primary indication

•A muscle contraction usually can be forced by electrically stimulating the muscle

•Provides artificial use of inactive synapses

•Restore normal balance to system as ascending sensory info is reintegrated into movement patterns

•Patient feels the muscle contract, sees the muscle contract, and can attempt to duplicate this muscular response

Muscle Pump Contractions•Used to duplicate the regular muscle contractions that help stimulate circulation by pumping fluid and blood through venous and lymphatic channels back to the heart

•Can help in reestablishing proper circulatory pattern while keeping injured part protected

•Sensory level stimulation has been shown to decrease edema in sprain and contusion injuries

Retardation of Atrophy•Electrical stimulation reproduces physical and chemical events associated with normal voluntary muscle contraction and helps to maintain normal muscle function

•No specific protocol exists clinician should try to duplicate muscle contraction associated with normal exercise routine

Increasing Range of Motion•Electrically stimulating a muscle contraction pulls joint through limited range

•Continued contraction of muscle group over extended time appears to make contracted joint and muscle tissue modify and lengthen

The Effect of Non-contractile Stimulation on Edema•Sensory level direct current used as a driving force to make charged plasma protein ions in interstitial spaces move in the direction of oppositely charged electrode

•Cook et al. hypothesized that

1) the electrical field facilitated movement of charged proteins into lymphatic channels

2) Electrical field caused indirect stimulation of autonomic nervous system, stimulating release of adrenergic substances, increasing smooth muscle activity and lymph circulation

Therapeutic Uses of Electrical Stimulation of Sensory Nerves – Asymmetric Biphasic Currents (TENS)•Gate Control Theory

•Descending Pain Control

•Opiate Pain Control

•Provide high frequency sensory level stimulation to stimulate peripheral sensory Aβ fibers and “close gate”

•Referred to as conventional, high frequency or sensory-level TENS

•Intensity is set at a level to cause tingling sensation without muscle contraction

•Pain relief lasts only while stimulation is provided

TENS & Gate Control Theory

•Intense electrical stimulation of smaller peripheral Aδ and C fibers through input to the CNS causes a release of enkephalins blocking pain at the spinal cord level

•Cognitive input from the cortex relative to past pain perception also contributes to this mechanism

•Low-frequency or motor-level TENS is used elicits tingling and muscle contraction

•Provides pain relief >1 hour

TENS & Descending Pain Control

•Noxious stimulus causes release of β–endorphins and dynorphin resulting in analgesia

•A point stimulation set-up must be used

•β–endorphin stimulation may offer better relief for deep aching or chronic pain

•Intensity of impulse is a function of pulse duration and amplitude

–Greater pulse width is more painful

TENS & Endogenous Opiate Pain Control

•Used to treat skin ulcers that have poor blood flow

–Accelerated healing rate has been noted

•Mechanism of enhanced healing is elusive

–Cells are stimulated to increase normal proliferation, migration motility, DNA synthesis and collagen synthesis

–Receptors for growth factor have also shown significant increases

Promotion of Wound Healing

•Could be used in fracture prone to non-union

•May accelerate healing via a monophasic current

–Getting current into area non-invasively is a challenge

Promotion of Fracture Healing

•Limited evidence

•Both tissues generate strain related electric potentials when stressed

–Signal tissue growth in presence of stress

•Increased fibroblastic activity, cellular proliferation, and collagen synthesis has been noted

•Increased histologic repair rates noted

Promotion of Healing in Tendons & Ligaments

Interferential Currents•When electrodes are arranged in a square and interferential currents are passed through a homogeneous medium a predictable pattern of interference will occur

•Interest on part of clinician impacts perception of the patient

•Perceptual change is influenced by cognitive and affective factors

–When active physiologic changes occur that can assist healing process

–Does not mean athletic trainer should intentionally deceive patient but should use treatment to have best impact on patient’s perception of problem and the treatment’s effectiveness

Placebo Effect of Electrical Stimulation

•Treatment will work best if patient has belief in its ability to alleviate the problem

•Patient needs to be intimately involved in treatment

–Educate

–Encourage

–Empower patient to get better

Contraindications for Electrical Contraindications for Electrical StimulationStimulation

PregnancyInfectionCancerous TumorPacemakerHead and genitals

Therapeutic Ultrasound

Therapeutic UltrasoundInaudible, acoustic vibrations of high Inaudible, acoustic vibrations of high frequency that produce can produce both frequency that produce can produce both non-thermal and non-thermal physiologic non-thermal and non-thermal physiologic effectseffects

Classified as a deep heating modality Classified as a deep heating modality with the ability to heat tissues to a greater with the ability to heat tissues to a greater degree in less time as compared to other degree in less time as compared to other superficial heating modalitiessuperficial heating modalities

Penetration vs. AbsorptionUltrasound penetrates through tissue high in Ultrasound penetrates through tissue high in water content and is absorbed by tissues with water content and is absorbed by tissues with high protein content high protein content

Tissues with high protein content possess Tissues with high protein content possess the greatest potential for heatingthe greatest potential for heating

Inverse relationshipInverse relationship

Penetration vs. AbsorptionAbsorption increases as frequency increasesAbsorption increases as frequency increases

Tissues high in water content decrease absorptionTissues high in water content decrease absorption

Tissues high in protein content increase absorptionTissues high in protein content increase absorption

Tissue absorption rates in descending order Tissue absorption rates in descending order

BoneBone

NerveNerve

MuscleMuscle

FatFat

Ultrasound At Tissue InterfacesSome energy scatters due to reflection and Some energy scatters due to reflection and refractionrefraction

Acoustic impedance determines the amount Acoustic impedance determines the amount reflected vs. transmittedreflected vs. transmitted

Acoustic impedance = tissue density X speed of transmissionAcoustic impedance = tissue density X speed of transmission

The most energy will the transmitted if the The most energy will the transmitted if the acoustic impedance is the sameacoustic impedance is the same

↑↑ difference in acoustic impedance = difference in acoustic impedance = ↑↑ reflected energy reflected energy

Reflection vs. TransmissionTransducer to air - Completely reflectedTransducer to air - Completely reflected

Through fat - TransmittedThrough fat - Transmitted

Muscle/Fat Interface - Reflected and refractedMuscle/Fat Interface - Reflected and refracted

Soft tissue/Bone Interface - ReflectedSoft tissue/Bone Interface - Reflected

Creates “standing waves” or “hot spots”Creates “standing waves” or “hot spots”

Therapeutic Ultrasound GeneratorsHigh frequency High frequency electrical generator electrical generator connected through an connected through an oscillator circuit and a oscillator circuit and a transformer via a transformer via a coaxial cable to a coaxial cable to a transducer housed transducer housed within an applicatorwithin an applicator

Therapeutic Ultrasound Generator Control PanelTimerTimer

Power meterPower meter

Intensity control ( watts or W/cmIntensity control ( watts or W/cm22))

Duty cycle switch (Determines On/Off time)Duty cycle switch (Determines On/Off time)

Selector switch for continuous or pulsed Selector switch for continuous or pulsed

*All units should be calibrated and checked *All units should be calibrated and checked regularly.regularly.

Transducer or ApplicatorMatched to individual units Matched to individual units and not interchangeableand not interchangeable

Houses a Houses a piezoelectricpiezoelectric crystalcrystal

QuartzQuartz

Lead zirconate or titanateLead zirconate or titanate

Barium titanateBarium titanate

Nickel cobaltNickel cobalt

Transducer or ApplicatorCrystal converts electrical Crystal converts electrical energy to sound energy energy to sound energy through mechanical through mechanical deformationdeformation

When an alternating current is passed When an alternating current is passed through a crystal it will expand and through a crystal it will expand and contractcontract

Piezoelectric Effect

Piezoelectric EffectIndirect or Reverse Effect - As Indirect or Reverse Effect - As alternating current reverses polarity the alternating current reverses polarity the crystal expands and contracts producing crystal expands and contracts producing ultrasoundultrasound

Crystal vibrates at a selected frequency Crystal vibrates at a selected frequency sound wave generated and passed to tissuessound wave generated and passed to tissues

Effective Radiating Area (ERA)That portion of the surface of the transducer That portion of the surface of the transducer that actually produces the sound wavethat actually produces the sound wave

Should be only slightly smaller than transducer Should be only slightly smaller than transducer surfacesurface

Acoustic energy is contained in a focused Acoustic energy is contained in a focused cylindercylinder

Energy output and temperature are significantly Energy output and temperature are significantly greater at center as compared to peripherygreater at center as compared to periphery

Treatment Area SizeShould be 2-3 times larger than the ERA of Should be 2-3 times larger than the ERA of the crystal in the transducerthe crystal in the transducer

Research has shown that treating too large an Research has shown that treating too large an area will not result in the desired increase in area will not result in the desired increase in tissue heatingtissue heating

Best if used on smaller treatment areasBest if used on smaller treatment areas

Frequency of Therapeutic Ultrasound

Frequency range of therapeutic Frequency range of therapeutic ultrasound is 0.75 to 3.3 MHzultrasound is 0.75 to 3.3 MHz

Frequency is the number of wave cycles Frequency is the number of wave cycles per secondper second

Most generators produce either 1.0 or Most generators produce either 1.0 or 3.0 MHz3.0 MHz

The Ultrasound BeamDepth of penetration is Depth of penetration is frequency dependent not frequency dependent not intensity dependentintensity dependent

1 MHz transmitted through 1 MHz transmitted through superficial layer and absorbed superficial layer and absorbed at 3-5 cmat 3-5 cm

3 MHz absorbed superficially 3 MHz absorbed superficially at 1-2 cmat 1-2 cm

Amplitude, Power, & IntensityAmplitudeAmplitude

Magnitude of the vibrations in a waveMagnitude of the vibrations in a wave

PowerPower

Total amount of US energy in the beam Total amount of US energy in the beam (expressed in watts)(expressed in watts)

IntensityIntensity

Rate at which energy is delivered per unit areaRate at which energy is delivered per unit area

Thermal vs. Non-Thermal EffectsThermal effects Thermal effects

Tissue heatingTissue heating

Non-Thermal effectsNon-Thermal effects

Tissue repair at the cellular levelTissue repair at the cellular level

Thermal effects occur whenever the spatial Thermal effects occur whenever the spatial average intensity is > 0.2 W/cmaverage intensity is > 0.2 W/cm22

Whenever there is a thermal effect there will Whenever there is a thermal effect there will always be a non-thermal effectalways be a non-thermal effect

Thermal Effects of UltrasoundIncreased collagen extensibilityIncreased collagen extensibility

Increased blood flowIncreased blood flow

Decreased painDecreased pain

Reduction of muscle spasmReduction of muscle spasm

Decreased joint stiffnessDecreased joint stiffness

Reduction of chronic inflammationReduction of chronic inflammation

Set at 1.5 W/cmSet at 1.5 W/cm22 with 1MHz ultrasound with 1MHz ultrasound would require a minimum of 10 minutes to would require a minimum of 10 minutes to reach vigorous heatingreach vigorous heating

Ultrasound Rate of Heating Per Minute

Intensity W/cm2 1MHz 3MHz

0.5 .04°C .3°C1.0 .2°C .6°C1.5 .3°C .9°C2.0 .4°C 1.4°C

There are no specific guidelines which dictate There are no specific guidelines which dictate specific intensities that should be used during specific intensities that should be used during treatmenttreatment

Recommendation is to use the lowest intensity at the Recommendation is to use the lowest intensity at the highest frequency which transmits energy to a specific highest frequency which transmits energy to a specific tissue to achieve a desired therapeutic effecttissue to achieve a desired therapeutic effect

Everyone’s tolerance to heat is different – get Everyone’s tolerance to heat is different – get feedback from patient during treatmentfeedback from patient during treatment

Adjust settings to patient toleranceAdjust settings to patient tolerance

Treatment should be temperature dependentTreatment should be temperature dependent

Set at 1.5 W/cmSet at 1.5 W/cm22 with 3 MHz ultrasound would require with 3 MHz ultrasound would require only slightly more than 3 minutes to reach vigorous only slightly more than 3 minutes to reach vigorous heatingheating

Intensity W/cm2 1MHz 3MHz

0.5 .04°C .3°C1.0 .2°C .6°C1.5 .3°C .9°C2.0 .4°C 1.4°C

Thermal EffectsBaseline muscle temperature is 36-37°CBaseline muscle temperature is 36-37°C

Mild heatingMild heating

Increase of 1°C accelerates metabolic rate in tissueIncrease of 1°C accelerates metabolic rate in tissue

Moderate heatingModerate heating

Increase of 2-3°C reduces muscle spasm, pain, Increase of 2-3°C reduces muscle spasm, pain, chronic inflammation, increases blood flowchronic inflammation, increases blood flow

Vigorous heatingVigorous heating

Increase of 3-4°C decreases viscoelastic properties Increase of 3-4°C decreases viscoelastic properties of collagenof collagen

Non-Thermal Effects of UltrasoundIncreased fibroblastic activityIncreased fibroblastic activity

Increased protein synthesisIncreased protein synthesis

Tissue regenerationTissue regeneration

Reduction of edemaReduction of edema

Bone healingBone healing

Pain modulationPain modulation

Literature indicates that non-thermal ultrasound Literature indicates that non-thermal ultrasound may modify cellular functionmay modify cellular function

Modulate membrane propertiesModulate membrane properties

Alter cellular proliferationAlter cellular proliferation

Produce increases in proteins associated with Produce increases in proteins associated with inflammation and repairinflammation and repair

Could modify inflammatory responseCould modify inflammatory response

Impact protein functionImpact protein functionInduce conformational shift Induce conformational shift change function change function

Dissociate multimolecular complex Dissociate multimolecular complex change function change function

Frequency of TreatmentAcute conditions Acute conditions

Require more treatment over a shorter period of time Require more treatment over a shorter period of time (2 X/day for 6-8 days)(2 X/day for 6-8 days)

Consider pulsed ultrasoundConsider pulsed ultrasound

Can begin using within 48 hoursCan begin using within 48 hours

Chronic conditions Chronic conditions

Require fewer treatments over a longer period Require fewer treatments over a longer period (alternating days for 10-12 treatments)(alternating days for 10-12 treatments)

Treatment should continue as long as there is Treatment should continue as long as there is progressprogress

Duration of TreatmentSize of the area to be treatedSize of the area to be treated

What exactly are you trying to accomplishWhat exactly are you trying to accomplish

Thermal vs. non-thermal effectsThermal vs. non-thermal effects

Intensity of treatmentIntensity of treatment

What is the desired effect?What is the desired effect?

Size of the Treatment Area

Should be 2-3 times larger than the ERA of the Should be 2-3 times larger than the ERA of the crystal in the transducercrystal in the transducer

If the area to be treated is larger use shortwave If the area to be treated is larger use shortwave diathermy, superficial hot packs or hot whirlpooldiathermy, superficial hot packs or hot whirlpool

Numbers Represent °C Increase Following Treatment

Intramuscular Temp 1 cm below fat layer at 3 cm after 10 min. after 4 minutes

Hydrocollator Pack 0.8°C -----

1 MHz Ultrasound 4.0 °C -----

Hot Whirlpool (40.6°C) ----- 1.1°C

3 MHz Ultrasound ----- 4.0°C

Ultrasound As A Heating Modality

(Smith, et al., 1995)

(Meyrer et al., 1994)

Direct ContactTransducer should be small Transducer should be small enough to treat the injured enough to treat the injured areaarea

Gel should be applied Gel should be applied liberallyliberally

Area to be treated should be Area to be treated should be larger than transducerlarger than transducer

Heating of gel does not Heating of gel does not increase the effectiveness of increase the effectiveness of the treatmentthe treatment

Immersion TechniqueGood for treating irregular Good for treating irregular surfacessurfaces

A plastic, ceramic, or rubber A plastic, ceramic, or rubber basin should be usedbasin should be used

Tap water is useful as a Tap water is useful as a coupling mediumcoupling medium

Transducer should move Transducer should move parallel to the surface at .3-5 cmparallel to the surface at .3-5 cm

Air bubbles should be wiped Air bubbles should be wiped awayaway

Bladder TechniqueGood for treating irregular surfaces Good for treating irregular surfaces when body part cannot be submerged when body part cannot be submerged in waterin water

Uses a balloon filled with waterUses a balloon filled with water

Both sides of the balloon should be Both sides of the balloon should be liberally coated with gelliberally coated with gel

Moving The TransducerStationary technique no longer recommended Stationary technique no longer recommended could result in hot spots could result in hot spots

Applicator should be moved at about Applicator should be moved at about 4 4 cm/seccm/sec

Low BNR allows for slower movementLow BNR allows for slower movement

High BNR may cause cavitation and periosteal High BNR may cause cavitation and periosteal irritationirritation

Moving the transducer too rapidly decreases the Moving the transducer too rapidly decreases the total amount of energy absorbed per unit areatotal amount of energy absorbed per unit area

Rapid movement may also cause the athletic Rapid movement may also cause the athletic trainer to treat too large an area, reducing the trainer to treat too large an area, reducing the ability to achieve the desired treatment ability to achieve the desired treatment temperaturetemperature

Lower BNR tends to allow for more slow Lower BNR tends to allow for more slow movement of the transducermovement of the transducer

If the patient complains of pain the intensity If the patient complains of pain the intensity should be lowered and the treatment time should should be lowered and the treatment time should be adjustedbe adjusted

Too much transducer pressure could impact Too much transducer pressure could impact acoustic transmissivityacoustic transmissivity

Clinical Applications For UltrasoundUltrasound is recognized clinically as an Ultrasound is recognized clinically as an effective and widely used modality in the effective and widely used modality in the treatment of soft tissue and bony lesionstreatment of soft tissue and bony lesions

There is relatively little documented, data-There is relatively little documented, data-based evidence concerning its efficacybased evidence concerning its efficacy

Most of the available data-based research is Most of the available data-based research is unequivocalunequivocal

Soft Tissue Healing and RepairEffects on inflammation processEffects on inflammation process

Cavitation and streaming increases transport of Cavitation and streaming increases transport of calcium across cell membrane releasing histaminecalcium across cell membrane releasing histamine

Histamine stimulate leukocytes to “clean up”Histamine stimulate leukocytes to “clean up”

Stimulates fibroblasts to produce collagenStimulates fibroblasts to produce collagen

Will liquefy gel-like cellular debrisWill liquefy gel-like cellular debris

Heating collagen will increase extensibility in Heating collagen will increase extensibility in the tissuethe tissue

Scar Tissue and Joint ContractureIncreased temperature causes an increase Increased temperature causes an increase in elasticity and a decrease in viscosity of in elasticity and a decrease in viscosity of collagen fibers collagen fibers

Increases mobility in mature scar Increases mobility in mature scar

When vigorous heating is achieved heated When vigorous heating is achieved heated tissues become more extensibletissues become more extensible

Collagen tissue becomes more Collagen tissue becomes more yielding when heatedyielding when heated

Active exercise is more effective than Active exercise is more effective than ultrasound in increasing intramuscular ultrasound in increasing intramuscular temperaturetemperature

Temperature increase does not appear to influence Temperature increase does not appear to influence range of motionrange of motion

Stretching windowStretching window

Time period of vigorous heating when tissue will Time period of vigorous heating when tissue will undergo greatest extensibility and elongationundergo greatest extensibility and elongation

Stretching Connective Tissue

Tissue heated with ultrasound cools at a Tissue heated with ultrasound cools at a very rapid ratevery rapid rate

Joint mobilizations and friction massage Joint mobilizations and friction massage should be performed shortly after heating due should be performed shortly after heating due to the elevated cooling rateto the elevated cooling rate

Stretching should be done immediately Stretching should be done immediately following ultrasound heatingfollowing ultrasound heating

Acute and post-acute Acute and post-acute conditions (non-thermal)conditions (non-thermal)

Soft tissue healing and repairSoft tissue healing and repair

Scar tissueScar tissue

Joint contractureJoint contracture

Chronic inflammationChronic inflammation

Increase extensibility of Increase extensibility of collagencollagen

Reduction of muscle spasmsReduction of muscle spasms

Pain modulationPain modulation

Increase blood flowIncrease blood flow

Increase protein synthesisIncrease protein synthesis

Tissue regenerationTissue regeneration

Bone healingBone healing

Repair of nonunion fxRepair of nonunion fx

Inflammation associated with Inflammation associated with myositis ossificansmyositis ossificans

Plantar wartsPlantar warts

Myofascial trigger pointsMyofascial trigger points

Indications

Acute & post-acute Acute & post-acute conditions (thermal)conditions (thermal)

Areas of decreased Areas of decreased temperature sensationtemperature sensation

Areas of decreased Areas of decreased circulationcirculation

Vascular insufficiencyVascular insufficiency

ThrombophlebitisThrombophlebitis

EyesEyes

Reproductive organsReproductive organs

Pelvis immediately following Pelvis immediately following mensesmenses

PregnancyPregnancy

PacemakerPacemaker

MalignancyMalignancy

Epiphyseal areas in childrenEpiphyseal areas in children

Total joint replacementsTotal joint replacements

InfectionInfection

Contraindications