Modalities Chap 10

What should you do if heat is too high on ultrasound? (Mensinger rule)

Turn the heat down and turn the time up

Energy exchange types for superficial heat

Conduction

Convection

Radiation

Conversion

Conduction

Transfer of energy via direct contact (hot pack)

Convection

Energy transfer via air or liquid movement (fluidotherapy, whirlpool)

Radiation

Energy transfer emitted from electromagnetic energy and absorbed by body (diathermy)

Conversion

Energy changes to another form. Ultrasound converts acoustic sound into thermal heat depending on how the tissue reflects or absorbs energy.

Depth of penetration for superficial heat treatment

2cm

Contraindications of heat

Older patients

Sensory issues (Can’t perceive burning from heat pack)

Poor circulation

Medically unstable

Coronary heart disease

Open wounds (Specifically for whirlpool and paraffin bath)

Arndt-Shultz Principle

Describes an optimal amount of energy for tissues

Law of Grotthuss-Draper

Energy absorbed in superficial layers can’t be transferred to deeper layers

How much does tissue temperature need to increase to change viscoelastic properties of it?

4 degrees celsius above baseline temp

Parameters for superficial heat

Temperature

• Whirlpool rule: the more body submerged, the lower the temperature

  • Wrist/hand up to 112 deg

  • Generally never above 115 deg

Duration

• 20 mins

Frequency

• Can be every day, active exercise is better for warmup (bike, treadmill)

Types of superficial heat

Moist hot pack

Warm water immersion

Paraffin bath

Fluidotherapy

Therapeutic ultrasound is ___ energy, but similar to ____ energy. Behaviors of this energy include:

Sound, light

Reflection: Light bounces off of smooth surface

Refraction: Light bends when passing through medium

Absorption: Light is taken by the material and converts to another form of energy (i.e. heat)

Contraindications of therapeutic ultrasound

Pregnancy

Cancer

Active infection

DVT

Pacemaker

Joint replacements

Applied over eyes/genatalia

Caution with peripheral vascular disease (PVD), sensory loss, and using over the spine

Ultrasound energy is created by the…

Reverse piezoelectric effect; electricity is moves through a crystal

Effective radiating area (ERA)

The actual area of the soundhead that is producing energy.

Treatment area should never exceed 2-3x the ERA (basically the size of the soundhead)

• If needed just do multiple treatments

Beam nonuniformity area (BNR)

Ratio between peak output and average output intensity.

*Crystals tend to not be perfect and may have more intensity in more areas of the soundhead. Lower ratio (left) is better than higher ratios (right) to avoid hotspots

Continuous vs. Pulsed ultrasound

Continuous: Significant temp increase

Pulsed: Non-temperature related effects

Parameters for ultrasound

Frequency: Depth of tissue penetration

• Superficial: 3MHz, up to 2.5 cm

• Deep: 1MHZ, 2-5 cm (uncommon irl)

Time: Relates to intensity, quantified with math

Intensity: How much energy is produced by transducer

Duty cycle: Percentage of energy being delivered during treatment (Continuous vs. pulsed;10-20-50%)

Goals for ultrasound duration from short to long duration

1 deg (celsius) increase = Increase metabolic activity

2-3 deg increase = Decrease muscle spasm and pain, increase blood flow

4 deg increase = Increase viscoelasticity of collagen

How does the math work for ultrasound duration for deep tissue and superficial tissue respectively? (Continuous)

1MHz (Deep tissue)

• For every 1 W/cm², tissue temperature increases 0.2 degrees celsius per minute (So, it takes 5 minutes to reach 1 deg celsius)

• For every 1.5 W/cm²; 0.3 deg celsius/min

• For 2 W/cm²; 0.4 deg celsius/min (Best for keeping treatment time short)

3MHz (Superficial tissue)

• For every 1 W/cm², 0.6 deg celsius/min (Now takes less time to reach 1 deg celsius, only a minute and some change)

• For every 1.5 W/cm²; 0.9 deg celsius/min (Better option since ultrasound can heat up too quickly and creating hotspots)

• 2 W/cm²; 1.2 deg celsius/min

What does ultrasound require for effective sound transmission?

Coupling medium

• Gel

• Biofreeze

• Water (Not effective just dont use it bro) (Only for underwater)

How to prevent discomfort and thermal damage

Proper movement

Proper parameter selection

Stretching window

Heat is dissipated 5-10 mins after ultrasound and effect is lost

How to take advantage of ultrasound treatment

Do ROM exercises immediately after application while tissue temperature is increased (within stretching window)

Nonthermal ultrasound

Pulsed ultrasound at 20/50% and low intensity. Mechanism of this is through acoustical streaming and cavitation

Proposed bone healing (-.5 2/cm², 20%, x5 minutes)

What is acoustical streaming?

Mechanism of nonthermal ultrasound where sound waves causes fast, one-way flow due to pressure changes in tissue

(One-way flow of tissue fluid)

Cavitation

Mechanism of nonthermal ultrasound that causes growth and collapse of microbubbles in the tissue, which the ultrasound oscillates and changes the pressure of. Theorized to;

• Increase vascular and also cell membrane permeability

• Increase protein and collagen synthesis via bloodflow

• Improving tensile strength of connective tissue

• Decreasing edema

Ultrasound effects

Increases tissue temperature

May improve blood flow

May reduce muscle spasms

Diathermy

Local heating via high-frequency electromagnetic waves that are typically..

• Shortwave

• Generate an alternating current at 27.12 MHz

Capacitance technique

Older form of diathermy that uses more of the electric of the electromagnetic field. Heating is caused by rapid rotation of the dipoles which cause

Inductance technique

Newer, more efficient, and more common form of diathermy that uses more of the magnetic of the electromagnetic field.

Greatest heating occurs in tissues with fewer _____. (And define the word)

Dipoles: Structures with positive and negative poles

Fewer dipoles (adipose tissue/fat)

Therefore least heating occurs in tissue with greater # of dipoles (skin and muscle)

Precautions and contraindications of diathermy

Precautions

• Metal implants and jewelry

• Heat sensitivity

• Medications

Contrain.

• Pacemakers

• Impaired sensation

• Infections

• Acute inflammation (unless non-thermal treatment is used)

• Large joint effusions

Diathermy parameters

Longwave, shortwave, and microwave

Frequency

• Typically 4-8 mHZ set by the unit

Power

• Example: 12-16 Watts = 1 degree increase

Pulse rate

• Example: 400-800 pulses/sec = 1 degree increase (in conjunction with duration)

Pulse duration

• Example: 100-200 microseconds = 1 degree increase (in conjunction with rate)

Non-thermal treatment

• Same effect as non-thermal ultrasound

Diathermy temperature objectives

Subacute inflammation = 1 degree tissue temperature increase

Pain reduction, muscle spasm, chronic inflammation = 2-3 degrees

Vigorous stretching, increase viscoelasticity of tissue = 4 degrees

Diathermy duration and rate of 1 degree tissue temperature increase

Subacute inflammation

• Duration: 100-200 microseconds

• Rate: 400-800 pulses/sec

Diathermy duration and rate of 2-3 degree tissue temperature increase

Pain reduction, muscle spasm, chronic inflammation

• Duration: 200-400 microsecond

• Rate: 400-800 pulses/sec

Diathermy duration and rate of 4 degree tissue temperature increase

Vigorous stretching, increase viscoelasticity of tissue

• Duration: 400 microseconds

• Rate: 800 pulses/sec

• Typically 20 min treatment (Like most diathermy treatments)

Diathermy effectiveness

Not proven to do much by itself, works better in conjunction with other treatments like stretching

May facilitate soft tissue stretching

Can heat large tissue volumes quickly (limited and controversial clinical studies on this)

Traction

Relieve radicular symptoms (pain, numbness, muscle weakness) caused by spinal nerve compression by decompressing/distracting the spine. Can be done mechanically (machine) or manually (hands).

Used for treatment for many issues

Manual traction

Using the hands to distract the cervical spine with ~15-25 lbs of force while patient is supine for 10 minutes. Neck positions change the outcome.

• Neutral: upper cervical separation

• Flexed ~30 deg: lower cervical

• Side bending/rotation: radicular symptoms

Used before mechanical traction is considered

Duration of manual traction outcomes

Intermittent: 30 seconds on, 30 seconds off (Not completely releasing tension)

• Disc issues: on time longer, off time shorter

• Facet joint issue: on time shorter, off time longer

Continuous: Consistent force for the entire duration of treatment (less desirable, hard to quantify with hands)

Mechanical traction

Using a machine to distract the spine with patient supine and pads snug under the skull. Appropriate if manual traction relieves symptoms.

• 15-25 lbs of force

• Intermittent traction (30s on/30s off) usually better tolerated than continuous

• Time: 20-30 mins

Precautions and contraindications of traction

Contraindications:

• Acute injury

• Dens fracture (may not be painful but still catastrophic if traction is applied)

• Instability

• Connective tissue disorders (Down syndrome, marfan, ehlers-danlos, prader-willi, rheumatoid arthritis)

• Vertebral cancer

• Vertebral artery compromise (Indicated by dizziness, sharp pain, vertigo, and vascular risk factors)

How to screen for spinal stability and dens fracture

Alar Ligament Test: Palpate C2 vertebrae, make sure that it rotates with head and it is not fractured

Lumbar traction

Spinal distraction at lumbar spine that requires greater force. Can be done with a harness

Setup: Prone or supine depending on comfort

Upper body needs as little clothing as appropriate

Starting force; ~25% bodyweight, can progress up to 50%

Precautions and contraindications of lumbar traction

Contraindications

• Pregnancy

• Hiatal hernia

• Advanced osteoporosis

• Fractures

• Cancer

Effectiveness of lumbar traction

Mixed; some benefits for patients with radicular pain and nerve root compression