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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
Units of power
Watts
26
How to choose duration for ultrasound?
2 minutes per finger width Maximum of 15 minutes or equivalent of 2x size of soundhead Approximately 1 minute per treatment head area
27
Pulsed ultrasound (duty cycle)
Machine turns on and off providing pulses of ultrasound
28
10% duty cycle
Ultrasound on for 10 μsec and off 90 μsec Used with fragile conditions Not very supported by research
29
20% duty cycle
Ultrasound on for 20 μsec and off 80 μsec Most commonly used setting Used for acute conditions
30
50% duty cycle
Ultrasound on for 50 μsec, and off 50 μsec Mild heating (not to therapeutic range) Used for subacute conditions
31
100% duty cycle
Ultrasound on consistently Required for thermal ultrasound Chronic conditions
32
Reasons you can use ultrasound
Pain control Soft tissue extensibility Surgical skin incisions Tendon injuries Phonophoresis Vascular and pressure ulcers Fracture healing
33
Parameters to decrease pain
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
Parameters to improve soft tissue extensibility
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
Low Intensity Pulsed Ultrasound (LIPUS)
Enhances wound healing due to mechanisms of cavitation and microstreaming The movement and compression of bubbles from cavitation cause changes in cellular activities
36
Parameters for fracture healing
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
Parameters for skin incisions or ulcers
Intensity: 0.5-0.8 W/cm2 Cycle: 20% pulsed Duration: 3-5 times/week May facilitate angiogenesis
38
Phonophoresis
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
Phonophoresis for myofascial trigger point
Hydrocortisone 1%
40
Phonophoresis for myofascial pain syndrome
Diclofenac
41
Parameters for phonophoresis
20% duty cycle to prevent heating 0.5-0.75 W/cm2 intensity 5-10 minutes
42
Transmissivity of ultrasound is related to conducting gel used
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
Precautions for ultrasound
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
Contraindications for ultrasound
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
Water-immersion techniques
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
Occupational therapy use of ultrasound
Use with other approaches such as exercises, strengthening, stretching, and functional movements Don't forget 10 minute window
47
Ultrasound for Inflammatory or acute phase (up to 7 days)
0.2 W/s2 20% duty cycle
48
Ultrasound for proliferative or sub-acute phase (3 days - 3 weeks)
Intensity: 0.2-0.8 W/s2 50% DC
49
Ultrasound for remodeling or chronic phase (2 weeks - 1 year or more)
0.8-2.0 W/s2 100% DC
50
Diathermy
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
Indications for diathermy
Joint inflammation Larger areas than ultrasound Fibrosis Myositis Subacute and chronic inflammation Osteoarthritis
52
Pulsed diathermy
Athermal Heating realted to rations of time on and off Affects ATP production and protein synthesis to enhance soft tissue healing
53
Continuous diathermy
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
Effect of diathermy application
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
Precautions for diathermy
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
Application of diathermy
Duration of treatment 20-30 minutes for 2 weeks When using higher treatment temperature, decrease duration of treatment and apply on alternate days
57
Contraindications for diathermy
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
Maximum intensity for 1 Mhz
2.0 W/cm2
59
Maximum intensity for 3 Mhz
1 W/cm2

Physical Agent Modalities (14 decks)

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