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Physical Agent Modalities > Therapeutic Ultrasound > Flashcards

Therapeutic Ultrasound Flashcards

1
Q

What tissue is ultrasound best at heating?

A

Dense collagenous tissue

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2
Q

Effects of thermal ultrasound

A

Increased tissue extensibility
Modify pain perception through activating free nerve endings

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3
Q

Parameters for thermal ultrasound

A

0.2-0.8 W/cm2 for mild heating
0.8-2 W/cm2 for therapeutic heating (cooking tissue)
Can use positional static stretch at same time

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4
Q

Diagnoses of thermal ultrasound

A

Bicipital tendonitis
Idiopathic carpal tunnel syndrome

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5
Q

Mechanical ultrasound

A

Facilitates healing of tissue and are due to varying pressure waves that cause cavitation, acoustic streaming, and micomassage
Achieved at 0.2 W/cm2
May be used for phonophoresis

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6
Q

Effects of mechanical ultrasound

A

Repairs bone and soft tissue
Decreases trigger point sensitivity
Stimulates protein and collagen synthesis
Decreased muscle spasms and pain
Reduced inflammation

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7
Q

Second order effects of mechanical ultrasound

A

Due to destabilization of membranes and subsequent increased cell permeability
Increased vascular permeability due to increased inflammatory response of histamine and vasoactive substances
Increase in phagocytic activity
Increase of fibroblasts in number and motility
Increased protein synthesis
Increased angiogenesis
Enhanced wound contraction

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8
Q

Diagnoses to use ultrasound

A

Tendinitis
Bursitis
Adhesive capsulitis
Trigger points
Contusions
Inflammation
Tendon repairs

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9
Q

Cavitation

A

Formation and collapse of gas or fluid bubbles
Stable cavitation occurs as a result of ultrasound at a 20% duty cycle, 3 MHz, and low intensity

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10
Q

Mechanism of ultrasound

A

When an electrical charge hits a crystal in the ultrasound unit, piezoelectric waves are created which are emitted from the ultrasound head as ultrasound waves
Amount of piezoelectric waves is proportional to amount of voltage
Sound energy is transmitted into the body causing molecules to vibrate and heat soft tissue

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11
Q

Spatial peak intensity

A

Highest intensity of beam and is found at the center of the beam

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12
Q

Spatial average intensity

A

Average intensity across the beam

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13
Q

Beam nonuniformity ratio

A

States how many times the peaks of intensity exceed pre-set values

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14
Q

Hot spots

A

Area of tissue that becomes over heated from too much concentrated energy in one area

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15
Q

Sound propagation

A

Transmission of sound through tissues through longitudinal, transverse (shear), or standing waves

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16
Q

Longitudinal waves

A

Transmit waves through soft tissues, liquids, and gasses

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17
Q

Transverse waves

A

Occur in solid media such as when wave reaches bone
Plays a significant role in bone healing

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18
Q

Standing waves

A

Sound wave moves through non-homogenous tissue resulting in some energy to be reflected causing periosteal heating and burning if sound head isn’t moved consistently enough

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19
Q

Attenuation

A

Decrease in intensity of energy due to absorption of energy by tissue or by reflection or refraction

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20
Q

Acoustic impedance

A

Resistance to wave energy by a medium
Greater impedance in tissues with more dense or heavy molecules
Fluid has elements have the lowest impedance values and acoustic absorption
Bone has the highest impedance value and highest acoustic absorption coefficient
Ultrasound waves continue through each tissue but is slightly refracted away from original position
Impendence levels from lowest to highest: fat, water, blood, muscle, bone

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21
Q

Frequency

A

Number of complete wave cycles generated each second
Influences amount of energy absorbed and determines tissue penetration depth

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22
Q

1 MHz frequency

A

Penetrates 5-7 cm

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23
Q

3 MHz frequency

A

Penetrates 1-2 cm

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24
Q

Intensity (W/s2)

A

Magnitude and strength of the force of a sound wave
Most significant factor in determining tissue response
Increased intensity = increased temperature

25
Q

Units of power

A

Watts

26
Q

How to choose duration for ultrasound?

A

2 minutes per finger width
Maximum of 15 minutes or equivalent of 2x size of soundhead
Approximately 1 minute per treatment head area

27
Q

Pulsed ultrasound (duty cycle)

A

Machine turns on and off providing pulses of ultrasound

28
Q

10% duty cycle

A

Ultrasound on for 10 μsec and off 90 μsec
Used with fragile conditions
Not very supported by research

29
Q

20% duty cycle

A

Ultrasound on for 20 μsec and off 80 μsec
Most commonly used setting
Used for acute conditions

30
Q

50% duty cycle

A

Ultrasound on for 50 μsec, and off 50 μsec
Mild heating (not to therapeutic range)
Used for subacute conditions

31
Q

100% duty cycle

A

Ultrasound on consistently
Required for thermal ultrasound
Chronic conditions

32
Q

Reasons you can use ultrasound

A

Pain control
Soft tissue extensibility
Surgical skin incisions
Tendon injuries
Phonophoresis
Vascular and pressure ulcers
Fracture healing

33
Q

Parameters to decrease pain

A

Frequency: 1 or 3 MHz
Intensity: 0.5 to 3.0 W/cm2
Duration: 3 to 10 minutes
Cellular changes elevate pain threshold, alter nerve conduction, and work as a counterirritant

34
Q

Parameters to improve soft tissue extensibility

A

Frequency: 1 or 3 MHz continuous ultrasound
Intensity: 1.0 W/cm2 or higher
Duration: 5 to 12 minutes
Ultrasound provides a 5-10 minutes window of opportunity for stretching

35
Q

Low Intensity Pulsed Ultrasound (LIPUS)

A

Enhances wound healing due to mechanisms of cavitation and microstreaming
The movement and compression of bubbles from cavitation cause changes in cellular activities

36
Q

Parameters for fracture healing

A

Frequency: 1 MHz
Intensity: 0.15 W/cm2 intensity
Cycle: 20% duty cycle
Duration: 15-20 minutes daily
Low intensity pulsed ultrasound for Coles’ and tibial fractures

37
Q

Parameters for skin incisions or ulcers

A

Intensity: 0.5-0.8 W/cm2
Cycle: 20% pulsed
Duration: 3-5 times/week
May facilitate angiogenesis

38
Q

Phonophoresis

A

Application of topical drug using ultrasound to directly deliver drug to a site to provide a systemic affect
Unclear effectiveness
Change in tissue permeability following ultrasound allows for improved absorption of medication and radiation pressure of ultrasound further drives in medicine molecules
Medication must pass through the epidermis and stratum corneum
Factors affecting passage include skin composition, hydration, vascularity and skin thickness

39
Q

Phonophoresis for myofascial trigger point

A

Hydrocortisone 1%

40
Q

Phonophoresis for myofascial pain syndrome

A

Diclofenac

41
Q

Parameters for phonophoresis

A

20% duty cycle to prevent heating
0.5-0.75 W/cm2 intensity
5-10 minutes

42
Q

Transmissivity of ultrasound is related to conducting gel used

A

Lidex gel, 0.05% fluocinonide (97%)
Methyl salicylate (97%)
Mineral oil (97%)
Ultrasound gel (96%)
Theragesic cream (91%)
Ultrasound lotion (90%)
0.05% betamethasone in ultrasound gel (88%)
Thick, white cream based 1% or 10% hydrocortisone creams do not transmit ultrasound

43
Q

Precautions for ultrasound

A

Over metal implants
Over epiphyseal growth plates or immature bone
Areas with sensory loss or decreased sensation
Over plastic or cemented implants
Subcutaneous or bony prominences
Care should be used in vicinity of cardiac pacemakers and implanted devices
Patients with decreased mentation, cognition, or communication skills
Avoid stationary transducer

44
Q

Contraindications for ultrasound

A

Over anesthetic areas
Over areas that have been irradiated
Carotid sinus
Over rash, eczema, or areas of skin irritation
Cancer or areas of malignancy
Over pacemakers, the heart, or implanted electronic devices
Patients with vascular disease, deep vein thrombosis, emboli, artherosclerosis
Patients with hemophilia not covered by factor replacement
Over eye or sex organs
Over uterus during pregnancy
Over stellate ganglions
Over spinal cord following laminectomy
Directly over external metal implants

45
Q

Water-immersion techniques

A

Often used when bony bumps or irregular surfaces are being treated with ultrasound
Body part is immersed in water and ultrasound head is moved over body part held 1 cm away from skin
Diminishes skin and subcutaneous heating to depth of 3 cm and little sensation of warmth is felt

46
Q

Occupational therapy use of ultrasound

A

Use with other approaches such as exercises, strengthening, stretching, and functional movements
Don’t forget 10 minute window

47
Q

Ultrasound for Inflammatory or acute phase (up to 7 days)

A

0.2 W/s2
20% duty cycle

48
Q

Ultrasound for proliferative or sub-acute phase (3 days - 3 weeks)

A

Intensity: 0.2-0.8 W/s2
50% DC

49
Q

Ultrasound for remodeling or chronic phase (2 weeks - 1 year or more)

A

0.8-2.0 W/s2
100% DC

50
Q

Diathermy

A

Uses radio waves with a short wavelength to cause heating due to friction caused by movement of ions from high frequency electromagnetic energy being transferred to kinetic energy
Tissues with high water content such as fat, blood, and muscle are selectively heated (4-6 C) at a depth of 2-5 cm
Deep heating effects last longer than ultrasound due to large area heated

51
Q

Indications for diathermy

A

Joint inflammation
Larger areas than ultrasound
Fibrosis
Myositis
Subacute and chronic inflammation
Osteoarthritis

52
Q

Pulsed diathermy

A

Athermal
Heating realted to rations of time on and off
Affects ATP production and protein synthesis to enhance soft tissue healing

53
Q

Continuous diathermy

A

Thermal
Mainly used for chronic injuries
Increases cell metabolism to enhance soft tissue healing
Heating occurs when total amount of energy delivered is greater than 38 watts

54
Q

Effect of diathermy application

A

Blood flow increases
Fibroblastic activity, collagen deposition and new capillary growth are stimulated
Muscle spasm is reduced by sedation of sensory and motor nerves
Local increase in cellular metabolic rate

55
Q

Precautions for diathermy

A

No metal (no hairpins)
Cover area with terrycloth to eliminate sweat
Explain to patient warmth should be felt but no unusual sensation
Requires physician prescription in some states
Never allow cables to touch
Do not allow for perspiration
Never allow direct contact with skin
Excessive fat in area may overheat area
Difficult to treat localized areas
Overheating may cause damage such as fat neurosis, deep aching or burning

56
Q

Application of diathermy

A

Duration of treatment 20-30 minutes for 2 weeks
When using higher treatment temperature, decrease duration of treatment and apply on alternate days

57
Q

Contraindications for diathermy

A

Ischemic areas
Peripheral vascular disease
Metal implants
Sensory loss
Pregnancy
Cardiac pacemakers
Perspiration
Tendency to hemorrhage including mensuration
Cancer
Areas of sensitivity such as epiphyseal plates, genitals, infected areas, abdomen, eyes, and face
Fever

58
Q

Maximum intensity for 1 Mhz

A

2.0 W/cm2

59
Q

Maximum intensity for 3 Mhz

A

1 W/cm2

Physical Agent Modalities (14 decks)

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