what are the main uses for cryotherapy?
what are factors to keep in mind when applying cold?
charting for cryotherapy
look at 4 small group activities for cryotherapy and heat therapy
- lecture slides
what are the 3 main uses for heat therapy?
1. Alter the viscoelastic properties of connective tissues
–Temperature ≥ 40C
–Predisposes tissues to viscoplastic deformation
2. Reduce pain (increase pain threshold)
–Multiple possible mechanisms
-study shown in lecture that superficial heat has moderate benefit (evidence quality: good, direct evidence) for treating people with acute low back pain - no inconsistencies,
3. Reduction in muscle spasm / muscle-guarding spasms
–Increase muscle temperature to ≥42°C (may require more than superficial heat)
–Reduction of tonic extrafusal fiber activity
•decrease the firing rate of type II afferents
•increase the firing rate of type Ib fibres from Golgi Tendon Organs
•likely a decreased in the firing of alpha motoneurons
charting for heat therapy
describe 2 main types of heat application
1) hot packs
2) paraffin wax
describe mechanisms of cryotherapy (from reading)
- modality of choice 24-72 hours after acute injury (inflammatory phase) in order to 1) reduce pain and 2) limit edema via (image)
*note that reduced blood flow is accompanied / preceded by a decrease in histamine and bradykinin release, which reduces many active inflammatory processes including outward fluid filtration from blood vessels (which causes edema). This effect is most prominent in the areas with the greatest drop in temperature.
*note also if tissue temperatures are reduced below 10°C for a period of time, a cold-induced vasodilation may follow the initial period of vasoconstriction (yet dialation is still below normal levels)
- limits secondary hypoxic tissue injury: Injury may compromise blood flow to the injured area. Cooling the tissue reduces the local metabolism, and therefore reduces cellular energy demands. This may prevent further cell death.
- slow nerve conduction velocity: via increaseing threshold for nerve depolarization (possibly contributes to analgesic effect of cold)
- negatives: reduces muscle force production, Cold-induced ischemia, due to excessive or prolonged cooling, can also lead to frostbite (tissue freezing / death),
what are the 3 ways in which thermal exchange can occur?
what factors will influence the cooling effect of a cold modality? (reading)
1) Temperature difference between cold object and soft tissue
2) time of exposure
3) thermal conductivity of area being cooled
4) total body surface area being cooled
5) Size of cooling agent / ability of cooling agent to maintain its temperature
6) activity level
7) type of cooling agent
*see reading for detailed explainations
*note also: cooled area to take longer to return to normal temperatures than a warmed area
* skin redness after cold application: due, in part, to vasodilation of the superficial blood vessels and oxygen does not dissociate as freely from hemoglobin at lowered temperatures; therefore, the blood passing through the venous system is highly oxygenated, giving a red color to the skin
effectiveness of cycling and contrast baths for cryotherapy?
guidelines for cryotherapy (reading)
what is heat therapy most commonly used for and what temperature is required to do so? (reading)
reduce pain (see figure) and to reduce tissue stiffness / alter tissue viscoelasticity
To provide a therapeutic effect, tissue temperature should be elevated to between 40°C to 45°C.
what are other effects of heating? (reading)
- see reading
what depths are acheivable for heat therapy?
- Superficial heat causes the greatest degree of temperature elevation within 0.5 to 2 cm of the skin surface
- At a depth of 3 cm, using clinically tolerable intensities, it is only possible to increase muscle temperature by ≤ 1°C
- most modalities reach within 1 to 3 cm of the skin surface
- slightly deeper level (within 1 to 5 cm of the skin surface) using other heating modalities (Continuous ultrasound, Continuous shortwave diathermy)
- heat transfer effect dependant on: Thermal conductivity of the tissues, Body volume exposed, Time of exposure
guidelines for therapeutic US?
* note: For thermal effects, higher intensity is desirable (as heating is based on energy absorption). An intensity of 1.5 W/cm2 may be appropriate.
calculation of treatment time (US)
other calculation of minimum treatment time (US)
suggested treatment frequency (US)
charting for therapeutic US
look over 3 group activities for therapeutic US
what are the 3 characteristics of a waveform?
suggested US treatment depth (reading)
what is treatment intensity?
what is the Beam Non-Uniformity Ratio (BNR)
describe the absorption/dissipation of energy in different types of tissue
Superficial tissues will absorb and attenuate energy, thus reducing the effective treatment intensity in deeper tissues (see treatment depth section, above, for description of half-value depth). Higher energy absorption by denser tissues also suggests that these more energy-absorbing tissues are more likely to respond to US treatment.
describe reflction and refraction wrt US
Other variables related to treatment intensity, often used in research related to US treatment:
define: pulse duration, pulse ratio, pulse period, pulse frequency, duty cycle, and coefficient of operation (and formulas)
parameters for treatment area (US)
describe thermal therapeutic effects (US)
describe non-thermal therapeutic effects (US)
describe non-thermal therapeutic effects of US wrt phases of tissue healing
contraindications for continuous and pulsed US (reading)
contraindications for superficial heat (reading)
contraindications for cryotherapy (reading)