1. Cryotherapy & Thermotherapy
Chapter 4
Therapeutic Modalities

2. Physiology Basics Vasodilation Vasoconstriction
Increased size of vascular structures
Means more oxygen to the tissue
Vasoconstriction
Decreased size of vascular structures
Useful for preserving compromised/injured cells/tissue

3. Physiology Basics Analgesia Metabolic rate Inflammation
Diminished/reduced sensation
Metabolic rate
Activity level of cells
Reducing MR can preserve cells damaged by injury
Inflammation
Series of events that hinder optimal function

4. Modalities Alter cell metabolism
Each 1.8°F (1°C) change in tissue temp. results in a 13%  or  in the tissue’s metabolic rate.
Energy absorbed by one tissue later can’t be transmitted to deeper layers.
Law of Grotthus-Draper
The more energy absorbed by superficial tissues  the amount absorbed by deeper tissue.

5. 5 Mechanisms of Energy (Heat) Transfer in the Body: Added or Removed
Conduction – transfer of heat through the direct contact between a hotter and a cooler area (2 objects touching each other)
Ice Massage, Hydrocollator Pack, Ice Pack
Convection – transfer of heat by the movement a medium (air, liquid) between regions of unequal temperature
Whirlpool
Conversion – energy is changed from one form to another; does not relate to superficial heat or cold
Electrical energy into heat, Acoustical energy into heat
Ultrasound, Diathermy

6. Mechanisms of Energy
Radiation – emitted from surfaces with temperatures above absolute 0° (all atomic & molecular motion ceases)
Transfer of energy without the use of a medium
Body, Sun, Infrared lamp, LASER, Ultraviolet light
Evaporation – change from liquid state to gaseous state requiring thermal energy be removed from the body
Vapocoolant Spray

7. Cryotherapy – Cold Therapy
Cold modalities range in temp. between 32°F-65°F
Heat is removed from the body & absorbed by the cold modality
Tissue temperature is LOWERED
To obtain therapeutic benefits, the skin temp. must be lowered to approx. 57°F.
Cold therapy applied is thought to activate a mechanism used to conserve heat in the body’s core
This mechanism triggers a series of metabolic & vascular events that produce the beneficial effects of cryotherapy.
Can be used during all stages of healing

8. Cryotherapy Normal skin temp. is approx. 91°F
The deeper the tissue in the body, the higher the temp.
Skin is cooler than adipose which is cooler than muscular tissue.
Thermoreceptors in skin are responsive to heat or cold (more to cold than heat).

9. Sensations with Cold Application
Burning
Aching
Analgesia (absence of pain)
 of n. conduction velocity &  threshold are required to fire the nerve(s).

10. Cryotherapy Indications
Acute injury or inflammation
Pain
Muscle spasm, acute or chronic
Restoration of ROM
Small, superficial, 1st degree burns
Post-surgical pain & edema
Neuralgia
Post-exercise

11. Cryotherapy Contraindications
Cardiac or respiratory involvement
Uncovered open wounds
Circulatory insufficiency
Cold allergy
Anesthetic skin
Advanced diabetes
Raynaud’s phenomenon or other Peripheral Vascular Disease
Lupus
Situations where the body is unable to cope with temp. change because of allergy, hypersensitivity, or circulatory insufficiency

12. Local Effects of Cryotherapy
 cell metabolism rate – PRIMARY BENEFIT
 need for oxygen
Lowers tissue temperature
Vasoconstriction
 production of cellular wastes
Prevents or limits swelling
 in pain by  pain threshold
 in acute & chronic muscle spasm
Limits area of original injury

13. Deeper tissues cool more slowly & to a lesser extent than skin
Muscle tissue requires longer to cool than bony areas
Deeper tissue temps. have been proven to drop for several minutes following the removal of an ice pack
Research has shown that deeper tissues remaining at rest will be cooled for 2 hr or more after a 20- to 30- min. ice pack application
The cold modality will continue to remove body heat until temps. are (=).

14. Precautions
Take into consideration the amount of pain that occurs during exercise after cold has been applied
Be careful when applying an elastic wrap over a cold pack over superficial nerves (Nerve Palsy)
Uticaria – hives

15. Cellular Response  cellular metabolic rate
During a 20-min. treatment, cell metabolism  19%
With  b. flow, there is less metabolic activity & O2 demand on the cells
 need for O2
Reduces number of cells killed by lack of O2
Reduces secondary hypoxic injury damage
Reduces amount of chemical mediators released in area
Slows nerve conduction

16. Vascular Responses
Vasoconstriction occurs due to stimulation of n. receptors
Viscosity of blood & tissue fluids 
Resistance to b. flow 
Soft tissue  of 26% & skeletal b. flow  of 19% with 20-min. ice pack in injured ankles
Amount of b. flow is still under debate
Most studies indicate that b. flow 
Because of effects associated with rubbing the skin, IM may  b. flow, at least to the skin

17. Tissue Temperature Changes
57°F skin temp. – optimal decrease in local blood flow
58°F skin temp. – analgesia occurs
Temp. within the joint decreases proportionally to temp. of skin overlying a joint decreases
Temp. changes most rapidly in skin & synovium

18. Muscle Spasm Cold therapy affects pain threshold
 nerve conduction velocity by slowing communication at the synapse
 pain by reducing the threshold of afferent n. endings.
 sensitivity of m. spindles
May inhibit the stretch reflex mechanism reducing m. spasm & breaking pain-spasm cycle

19. Inflammation
Changes in cellular function & blood dynamics serve to control effects of acute inflammation.
Cold suppresses the inflammatory response by:
 the release of inflammatory mediators (histamine, prostaglandin)
 prostaglandin synthesis
 capillary permeability
 leukocyte/endothelial interaction
 creatine-kinase activity

20. Pain Control Cold therapy acts as a counterirritant
Cold application affects pain perception & transmission by:
Interrupting pain transmission (stimulates large-diameter A-beta n. fibers)
Decreasing n. conduction velocity
Reducing m. spasm
Reducing or limiting edema

21. Systemic Effects of Cold Exposure
If circulating blood temp.  0.2°F, then the hypothalamus (body’s thermoregulatory center) kicks in
General vasoconstriction in response to cooling of the posterior hypothalamus
Decreased respiratory & heart rates
Heart rate  (wants to localize the cold area)
Shivering & increased muscle tone
If heart rate  too much where the core temp. reaches hypothermia

22. Application of Cryotherapy
Ice Massage: Should not be applied during acute inflammatory stage as it’s not compatible with compression
5-15 mins. – reduces pain, desensitizes trigger points
Vigorous Ice Massage
Ice Pack: type of ice – cubed, flaked
Commercial Cold Packs: chemical, reusable (Gel)
Be aware of frostbite; use insulating layer in between
Cryo-cuff/Polar Care: provide approx. 40 mm Hg
Cold Water Immersion:
Ice bucket: 40 °-50°F
Whirlpool: 50 °-60°F
Vapocoolant Spray: superficial, rapid cooling through evaporation; virtually no temperature change below epidermis; will numb area briefly (trigger points)
Intermittent Compression: Segmental compression with cold

23. Cryotherapy
Duration usually15-30 mins. Don’t apply for more than 60 minutes!
Depends on skinfold thickness
Ice with compression – affects deeper tissues
Compression encourages  lymphatic drainage
Circumferential: compression around entire area (ace wrap)
Collateral: compression on both sides (aircast, gelcast)
Focal: direct pressure to soft tissue surrounded by bony structure (horseshoe)
Cooling of tissue: rapid at first, then slows, then levels off
Skin reactions:
Hyperemia, pallor

24. Cryokinetics for Sub-Acute Injury Stage
Alternating cold therapy with exercise
Use good judgment! Do not cause further harm!
Place cryotherapy to body part for approx. 20 min. (analgesia feeling)
Remove cryotherapy & begin active exercise
Place cryotherapy back on body part once feeling/pain returns
Repeat

25. Hunting Response
1930’s ; Lewis performed skin studies with temperature change during cold treatments.
When the fingers were immersed in cold water, alternating periods of cooling & warming were seen in the skin.
Thoughts were that intermittent cold-induced vasodilation (CIVD) lasting 4-6 min. after approximately 30 min. of cryotherapy application (p. 109)
Stated that it prevented local tissue injury
Today’s researchers state that CIVD does not occur during standard cryotherapy sessions.

26. Cryotherapy (Ice) Application Ice massage 7-10 minutes
Excellent for muscle spasm and deep soreness

27. Cryotherapy (Ice) Application Ice bags, ice towels, or cold packs
15-20 minutes (no longer than 30)
If using packs, be sure to avoid direct contact to protect skin!
Cold whirlpool / ice immersion
5-15 minutes, degrees
Duration and temperature depends on surface area immersed

28. Ice Massage

29. Ice Pack

30. Chemical Cold Pack

31. Reusable Gel Pack

32. Cryo-cuff

33. Ice Bucket

34. Cold Whirlpool

35. Fluori-methane