Cryotherapy and Thermotherapy

Question 1

What is Cryotherapy?

Answer 1

Cryotherapy is defined as the therapeutic application of any substance to the body that removes heat from the body, resulting in decreased tissue temperature (Kruse et al 2004
Clinically : Application of ice to the painful/swollen area

Question 2

What is the history of Cryotherapy?

Answer 2

Ice therapies have been used for a very long time – dating back to Hippocrates.
The physical effects of ice and cold are still not perfectly clear and some have been assumed without the research behind it.
Lack of research into the therapeutic effects and benefits
clinical experience (empirical experience) guides us to continue to recommend it.

Question 3

What are the Physiological effects of cryotherapy?

Answer 3

Ice application to an area:
Reduces blood flow,
reduce inflammation and swelling that causes pain.
Temporarily reduce nerve activity, which can also relieve pain.
Effects of cold:
Reduction in blood flow
Decreased in neural conduction velocity
Pain control
Decreased muscle spasticity
Reduces oedema
Reduction in metabolic rate
Hunting Reaction

Question 4

How does cryotherapy contribute to reduction in blood flow?

Answer 4

Drop in the temperature
Decrease in the release of vasodilators – such as histamine and prostaglandin
This decrease in vasodilator release results in vasoconstriction  decrease in blood flow
Drop in temperature
Stimulates the cutaneous thermoreceptors  stimulates smooth muscle contraction and the spinal cord dorsal root ganglion  vasoconstriction  decrease in blood flow
At lower temperature
increased interactions between the RBCs and between plasma proteins and red cells.
This can cause the red cells to stick together
Increases blood viscosity.
Decreases blood flow

Question 5

How does cryotherapy help with reduction of muscle spasm?

Answer 5

Spasm is a normal response to injury or pain
Increase in muscle tone in an area
AIM – limit movement and further damage
An exceeding amount of spasm and sustained contraction of muscles  pain and more spasm
Structures are deep
Several minutes to cool enough to effect them
Occurs within 30s - can only be at the superficial tissues at the skin
Skin stimulus (cold) must effect the general level of excitation and inhibition in the region of the anterior horn cells (α-motor neurons)

Question 6

How does cryotherapy contribute to a Reduction in neural conduction velocity?

Answer 6

Decreases the activation threshold of tissue nociceptors and the conduction velocity of pain nerve signals (Kruse 2004).
Result = local anaesthetic effect called cold-induced neuropraxia
Small myelinated fibres are more effected by the cold than the larger myelinated fibres, or the unmyelinated fibres.
Pain and temperature are conducted along small myelinated fibres called you’re a-delta fibres
Sodium channel opening is slowed  conduction of the signal is decreased along the axon.
Nerve axons also become less permeable to sodium = slower influx of sodium = slows down nerve conduction

Question 7

How does cryotherapy contribute to reducing oedema?

Answer 7

Acute inflammation:
Oedema is caused by extravasation of fluid into the interstitium due to increased intravascular fluid pressure and increased vascular permeability.
Further research is necessary to determine the effects of ice on post-traumatic oedema
Reduce temperature  Decrease in the release of vasodilators (histamine + prostaglandin  Vasoconstriction  Decrease in blood flow to the area = Decrease intravascular pressure

Question 8

How does cryotherapy contribute to reduction of pain?

Answer 8

Different hypotheses have been proposed (Camargo 2010):
closing of the pain gate,
counter-irritant effect that activates inhibitory control mechanisms,
increase in the activation threshold of nociceptors,
participation of descending pathways of the central nervous system that modulate pain by releasing endogenous opiates
An increase in pain threshold and pain tolerance associated with a decrease in NCV.

Question 9

How does cryotherapy contribute to reduction of metabolic rate?

Answer 9

Cold decreases the rate of all metabolic reactions, including those involved in the inflammation and healing processes.

When an injury occurs, the release of substances from damaged cells activates the production of inflammatory chemical mediators. These mediators are involved in enzymatic changes related to pro-inflammatory enzymes released as acid hydrolases, phospholipases, proteases and neutrophils. These substances are responsible for attracting more circulating inflammatory cells as neutrophils and macrophages. Neutrophils had an important role in degradation of damaged cells produced by primary injury; however, their oxidative reactions promote cytokines release which activates inflammatory cells and increased production of free radicals. This reaction causes damage to cellular membrane resulting in increased injury. Thus, restrictions in inflammation process as lowering the concentration of oxidants derived from neutrophils can reduce the tissue damage. (Freire 2016)

Question 10

The constriction and dilatation of the blood vessels is caused by the what?

Answer 10

release of neurotransmitters from the sympathetic nerves

Question 11

What are the indications for ice applications?

Answer 11

ACUTE sprains/strains
ACUTE inflammatory process : arthritis, bursitis, tendonitis, myositis, neuritis
ACUTE trauma
ACUTE and chronic muscle spasm

Question 12

What are relative contraindication for ice application?

Answer 12

Weakened individual
Old age
Infancy
Cachexia
Myocardial weakness
High blood pressure
Hypersensitive individuals

Question 13

What are total contraindications for ice application?

Answer 13

Areas of reduced sensation
Infected areas
Potential Malignancy
Circulatory Disturbances
Raynaud’s disease
Peripheral vascular disease
Severe varicose veins

Question 14

How do you apply ice?

Answer 14

Maximum cooling occurs at the skin, and the deeper you go the longer it takes for it to get cooled by the applied ice/cold.
Skin is quick – 5mins
Drop in the intra-muscular temperature – 20-30mins

The more adipose tissue a person has just below the skin, the longer it takes for the intra-muscular temperature to drop.
There is an increased distance between the skin and the muscle.

Things to consider when applying ice to the area of complaint:
Avoid prolonged application and therefore tissue damage
Place cold or moist cloth between ice and skin
Never direct contact
Consider applying simultaneous heat to other body parts to prevent generalised chilling
Warm patient after treatment if chilling occurs

Question 15

What are the different types of cryotherapy?

Answer 15

Ice/Cold pack
Reusable gel (silica) filled plastic bag
Remains flexible
Keep in freezer
Wrap in towel
Cools ~ 20mins

Instant cold compress
Endothermic reaction occurs when container within is broken
Single use
First aid – sports field
Wrap in towel

Ice Massage
Effective mode of cold transfer
Ice cube on skin directly
Continuous movement to prevent ice burn
Numbness reached in 5-10mins

Evaporating Sprays
Spraying a rapidly evaporating liquid on the skin has the effect of using heat energy  cooling the surface
Rapid cooling but short-lasting

Cold water immersion

Question 16

What is thermotherapy?

Answer 16

Thermotherapy is the therapeutic application of any substance to the body that adds heat to the body resulting in increased tissue temperature (Nadler et al 2004)

Thermotherapy is the oldest and most widely used
Natural forms : sun, sun-heated sand, thermal waters

Thermotherapy:
↑Tissue temperature
↑ Blood flow
↑ Metabolism
↑ Connective tissue extensibility
↓ Pain

Question 17

How does thermotherapy contribute to increased blood flow?

Answer 17

Rise in superficial temperature:
stimulates the cutaneous thermoreceptors.
The indirect activation of the local spinal cord reflexes by the cutaneous thermoreceptors leads to a decrease in sympathetic output = vasodilation
Smooth muscle is involuntary – in the BV walls - decrease in smooth muscle contraction  vasodilation at the site of heat

Rise in superficial temperature:
Causes the release of chemical mediators of inflammation – bradykinin Bradykinin and NO act as vasoactive mediator, ↑ vasodilator release relaxation of smooth muscle within the BV walls = vasodilation

Due to the depth of skeletal muscle, superficial heating of the painful area does not affect it that much. The metabolic factors influence the muscle blood flow rather than the changes to sympathetic activity.

Question 18

How does thermotherapy contribute to increased metabolic reactions?

Answer 18

Increase in temperature = increase in metabolic reactions
↑ temperature = ↑ rate of enzymatic reactions = ↑increase in metabolism.
Any increase in enzyme metabolic activity will result in an increase in cellular biochemical reactions

Question 19

How does thermotherapy contribute to increased collogen extensibility?

Answer 19

Heat-induced changes in the viscoelastic properties of collagenous tissues may underlie the demonstrated efficacy of heat therapy for improving range of movement (Malanga et al 2014).

↑ in temperature = ↑ in viscosity of collagen fibres = relax

Increase in extensibility does not occur unless heat treatment is associated with stretching exercises

Question 20

How does thermography contribute to pain relief?

Answer 20

Effect may be due to:
Gating of the transmission of pain by activation of cutaneous thermoreceptors.

Activated heat receptors inhibit the activity of purine pain receptors
Previous studies have suggested that temperature can affect the exchange between Ca2+ and Na+ in neural cells. They have documented an ↑ in both pain threshold (PTH) and pain tolerance (PTO) with the use of cooling

Question 21

How does thermography contribute to a decrease in muscle spasms?

Answer 21

Increase in temperature:
Lessen nerve sensitivity, increase blood flow, increase tissue metabolism, decrease muscle spindle sensitivity to stretch, cause muscle relaxation, and increase flexibility.
Heat stimulates the cutaneous thermoreceptors that are connected to the cutaneous blood vessels, causing the release of bradykinin which relaxes the smooth muscle walls  vasodilation.
Muscle relaxation occurs as a result of a ↓ firing rate of the gamma efferents, thus ↓ the threshold of the muscle spindles and ↑ afferent activity.

There is also a ↓ in firing of the alpha motor neuron to the extrafusal muscle fibre, resulting in muscle relaxation and ↓ in muscle tone.

Question 22

How does thermotherapy contribute to increased inflammation?

Answer 22

Heat is also believed to assist inflammation and swelling by a number of related factors such as such as
raising temperature,
increasing metabolism,
reducing oxygen tension,
lowering the pH level,
increasing capillary permeability,
releasing histamine and bradykinin (peptide chemical that causes pain in an injured area), (cause vasodilation)

Question 23

What are indications for heat therapy?

Answer 23

Subacute and chronic
Strains, sprains, bursitis, tenosynovitis, tendonitis
Arthritic and rheumatoid conditions (local or systemic)
Peripheral nerve injuries
Superficial infections
Muscle spasm
Application before another procedure ie:
Massage
Exercise
Manipulation

Question 24

What are relative contraindications for heat therapy?

Answer 24

Young or elderly patients
Pregnant patients
Hypersensitive individuals

Question 25

What are absolute contraindications for heat therapy?

Answer 25

Areas of reduced sensation
Infected areas
Potential Malignancy
Circulatory Disturbances
Acute inflammation
Damaged skin

Question 26

How do you apply heat?

Answer 26

Test to judge temperature before application
When in direct contact, pad bony prominence and/or sensitive areas
Never apply heat for such a long time as to cause prolonged tissue congestion
Max. benefitcial effect of heat  first 20-30 mins
>30 mins  blood flow plateaus and then declines (may increase oedema!)

Question 27

What are different types of heat therapy?

Answer 27

Hot packs – hydrocollator packs
heat by conduction, must remain moist
Heats bentonite-filled packs in water
<70°C
Wrapped in towel and applied to area

Heating pads and hot water bottle
Not as penetrating as hydrocollator packs
Soothing for patient
Easy access – fill HWB with hot water and apply to area (covered)
20mins every hour 3-4 x Day

Paraffin Baths
Paraffin wax – high heat capacity
Melts (retains more heat)  hand/foot dipped into it  changes to solid
Heat transferred from wax to area

Counter irritants
Deep heat/witch hazel/ tiger balm
Contain irritant (capsaicin)
Triggers thermoreceptors
Provides pain relief but no increase in blood flow

Question 28

What is contrast therapy?

Answer 28

Pumping effect  heat = vasodilation; cold = vasoconstriction

Indicators:
Subacute and chronic
Oedema
Arthritic conditions

Application
2:1 ratio
Heat for 20mins; ice for 10 mins
Can be repeated every 1-2 hours