Deep Heat: US and Diathermy Flashcards
Therapeutic Ultrasound
- Converts electrical energy to acoustical energy
- Thermal and non-thermal effects
- Frequencies between 1MHz-3MHz
Ultrasound Principles: Transducer
the head that converts one form of energy to another
Ultrasound Principles: Piezoelectric crystal
-A crystal capable of contracting and expanding “piezoelectric effect”
Reverse Piezoelectric effect
-as the AC reverses polarity, the crystal expands and contracts, producing ultrasound energy
Effective Radiating Area (ERA)
- Area of the sound head that produces ultrasonic waves
- Expressed in cm^2
- Energy output and Temp are greater at center
Beam Profile
-Multiple waves emerge uniformly, close to head and then become less consistent farther away (Spatial peak intensity)
Beam Nonuniformity Ratio (BNR)
- The consistency of the US output
- Ratio between the highest intensity in an US beam and the output reported on the meter
- 1:1 ideal, 8:1 unsafe
- Lower BNR reduces hot spots and reduces risk of periosteal pain; must keep the US head moving
FDA Labeling Requirements
- Output frequency
- Effective Radiating Area (ERA)
- Beam Nonuniformity Ratio (BNR)
- Beam profile
- Date of last service/calibration
Sound Energy Absorption in Tissues
- Tissues with higher protein density have higher rate of absorption: Tendons, ligaments, muscle tissues absorb high amount of energy
- Blood and fat have high water and absorb little US energy
- Cartilage and bone are at high end of absorption spectrum but is likely to reflect US due to the surface
US Parameters: Frequency
- Mainly use 1-3 Megahertz (1,000,000 cycles per second)
- 1MHz = low
- 3MHz = high
- Determines depth of treatment which is INVERSELY related to frequency
- 3MHz is more superficial(2cm)
- 1MHz is deep tissue(4cm>) and heating effects last longer
Dosage (Intensity)
- Watts/surface area (W/cm^2)
- Higher dose means higher amount of sound energy delivered to the tissues in less time
- Longer tx time needed for lower intensities
- Common: 1.5 w/cm^2
- Greater than 2.5-3 w/cm^2 may cause tissue damage
Tx Time and Thermal effects
- Most effective parameters for increasing muscle temp = increased by 4 degrees celsius or greater
- RX time 5-10 min (no less than 3min)
Treatment Area
- No greater than 2-3 times the ERA
- Move in slow manner to prevent hot spots
Coupling Methods
- Direct coupling: Gels made of distilled water and non-reflective material to increase viscosity
- Move sound head approx 4cm/sec
- Pad(bladder) coupling: formed from US gel and packed tightly in order to hold shape
- Advantages: conforms to irregular shaped areas and limits the size of tx area allowing more energy to be transmitted - Immersion: To treat irregular areas (1 inch away from area at 90 degree angle)
Duty Cycle: Continuous vs. Pulsed
Continuous: thermal effects
Pulsed: non thermal effects at cellular level
Thermal Effects: Mild heating
-1 degrees C results in increase metabolic activity, initiation of inflammatory process
Thermal Effects: Moderate Heating
-2-3 degree C results in increase of blood flow, decrease in pain, muscle spasm and chronic inflammation
Thermal Effects: Vigorous heating
-4 degree C results in improved viscoelastic properties of collagen
Non-thermal Effects: Stable Cavitation
-rhythmic contraction and expansion of gas bubbles; facilitates fluid movement and membrane transport
Non-thermal Effects: Unstable cavitation
-The formation of bubbles at the low pressure part of the US cycle; results in bubble collapse and tissue damage
Non-thermal Effects: Acoustical Microstreaming
- Unidirectional movement of fluids along the boundaries of cell membranes
- Increases Sodium and calcium permeability at cell membrane
US/E-Stim
- Treats: trigger points and muscle spasms
- Parameters: Thermal US and motor level E-stim
- Transducer head and dispersive pad
Phonophoresis
-US is used to deliver a medication via a safe, painless, noninvasive technique
Short Wave Diathermy
-Therapeutic generation of local heating by high frequency electromagnetic waves
SWDiathermy: Advantages
- thermal effects similar to US but effect deeper tissue
- Heats larger area of tissue
- Doesn’t reflect from bone so less likely to create hot spots
- Pulsed current can create thermal effects as well, heat retained 3 times longer
SWDiathermy: Disadvantages
- Expensive
- Only treats one patient at a time
- Potential for burns
Pulsed SWD
- Heats deep tissue
- Depths of 3-5 cm via high frequency current
SWD: Induction field generators
- Places patient in electromagnetic field
- Produce greatest heat within the muscle directly beneath the coil
- Induction cable or Induction drum
SWD: Capacitive Field Generators
- Body is actually placed in the electric field; part of circuit between 2 electrodes of opposite charge
- Tissues with greatest resistance create most heat as current flows through path of least resistance
- Not recommended for pts with thick adipose tissue
Indications for Traction
- HNP (prolapse, protrusion, extrusion)
- Facet impingement/malalignment
- Facet joint hypo mobility
- DDD/DJD
- Stenosis (central or lateral)
- Muscle spasm
Types of Traction
- Manual - more specific to segment (cervical)
- Positional - Ideal for localizing segment
- Mechanical
- Bed Traction-pulleys on bed
- Cottrell 90/90 - Posterior tilt; pt pulls on rope to increase post P tilt = good for lateral stenosis, not HNP
- Inversion boots
- Home doorway
Lumbar Traction Technique
-Measurabel separation of lumbar segments from 80-200 lbs
-Traction force of 1/2(never more) body weight is needed on slip table
-Begin at 25-50 lbs then increase by 5-15 lbs per session
Duration: 5-10mins first session; then 20-30 minutes
Cervical Traciton: Position
- Mid cervical(C2-5): 10-20 deg
- Lower(C5-7): 25-30 degrees
- 0-5 degrees for upper c spine
- Max separation at approx 24 degrees of flexion
Cervical Traction Technique
- 25-40 lbs of force is necessary to demonstrate a measurable change in Cervical spine
- Seperation of atlanto-occipital joint with 10 lbs of traction
Cervical Traction: Force
-Start at 8-10 lbs
-Nerve root or facet 20-30 lbs
-Disc, soft tissue stretch: 12-15 lbs
-Increase at 3-5 lbs per session
-Do not exceed 2x weight of pts head (~30lbs)
Duration:
-HNP = 60/10, 5-10 mins
-Joint/muscle = 30/10, 10-15 mins
Contraindications of Traction
- Acute Injuries
- Unstable spine
- Vertebral fxs or dislocations
- Rheumatoid arthritis
- Vertebral artery problems or vertigo
- Ankylosed (natural fused) segments
- Pregnancy for lumbar
- Recent surgery to ab or Tspine
- Fused spine
- Osteoporosis
- Cancer
- Local infection
