Cryo – Ice, low temperature
Therapy – treatment
                The treatment of pathological lesion by the use of low temperature agents such as ice, frozen gel packs and vapocoolant sprays. It has clinical application in therapeutic s and diagnostics, so is widely used in rehabilitation and other areas of medicine. It exerts its therapeutic effects by influencing hemodynamic, neuromuscular and metabolic processes.

Physiological effects of Cold:

Hemodynamic effects:

When cold is applied to the body it causes an initial decrease in blood flow due to the vasoconstriction of the cutaneous blood vessels. This vasoconstriction persists if the duration of the cold application is limited to less than 15 – 20 minutes. The vasoconstriction caused by cold is brought about both by the direct and indirect mechanisms.

Direct effects:

Ø  Increases viscosity of blood ----- decrease blood flow -----vasoconstriction
Ø  Activation of the cutaneous cold receptors -----stimulates the smooth muscles of the blood vessel walls to contract-----vasoconstriction

Indirect effects:

Ø  Decrease production and release of vasodilator mediators such as histamine and prostaglandin-----reduced vasodilatation
Ø  Decreased sympathetic adrenergic activation----- decrease production and release of vasodilator mediators such as histamine and prostaglandin----- reduced vasodilatation

Lewis hunting effect:

The immediate vasoconstriction response to cold may be followed by marked vasodilatation which itself may last for some 15 minutes before being replaced by another episode of vasoconstriction.
Lewis in 1930 observed that after 15 minutes of cold application, causing vasoconstriction, there is cyclic vasodilatation followed by vasoconstriction. This effect is called Lewis Hunting effect.

Neuromuscular effects:

Cold has a wide effect on the neuromuscular function;

a)     Reduces the nerve conduction velocity:

The nerve conduction velocity decreases in proportion to the degree of cooling. Decreased nerve conduction velocity has been documented with five minutes of application of cold, it fully reverses after 15 minutes. Cold can decrease the velocity of conduction ion both sensory as well as motor nerves.  It has greater effect on myelinated and small diameter fibers than unmyelinated and large diameter fibers.

b)     Increases the pain threshold:

A decrease in pain after cold application is due to increased pain threshold, through pain gate mechanism and reduction of muscle spasm and sensory nerve conduction velocity (especially small diameter myelinated pain transmitting fibers)

c)      Facilitates muscular contraction:

Brief application of cold facilitates the muscle contraction by enhancing excitability of the alpha motor neuron.

d)     Decreases spasticity:

It reduces spasticity for 1 – 1.5 hours, if applied for 30 minutes.

Metabolic effects:

Cold reduces the metabolic rate contrary to the heat that is why it is used in acute inflammation
It reduces the production of cartilage destroying enzymes i.e. collagenase, elastase, protease, hyaluronidase, etc that is why this modality is highly recommended in Acute osteoarthritis, rheumatoid arthritis, etc.

Techniques for application of Cryotherapy:

The various techniques that are used for administering cold are:
1         Ice towel
2         Ice packs
3         Immersion
4         Excitatory cooling/Ice massage

1       Ice towel:

This is popular method of application because there is little danger of producing an ice burn.

Patient preparation:

·         Prepare the bed
·         Remove the bed sheath
·         Remove the clothes from the area to be treated
·         Put water proof sheath on the bed like plastic etc

Ice towel preparation:

·         Prepare the ice solution by filling the bucket with two parts of crushed ice to one part water
·         Towel is immersed in the bucket and then wrings to remove excess water

2       Ice packs:

An ice pack is consisting of a gel made from silica or a mixture of saline and gelatin, which is covered by a plastic covering. The ice pack is rolled in a towel and applies the area to be treated.

3       Immersion:

In this technique the part to be treated is immersed in an ice solution (50% ice and 50% water). The technique is used for distal parts such as the hand and feet. The part to be treated is either immersed for a single 10 minutes session or a series of shorter immersions are made until a cumulative total of 10 minutes has been reached.

4       Excitatory cold:

The sensory stimulus of ice on the skin can be used to facilitate contraction of inhibited muscle. The ice is stroked quickly three times over the dermatome and skin is ten dried. This sensory stimulus passes via the peripheral nerve and enters the cord through posterior horn. It raises the level of excitation around the anterior horn cell (as ACH has connection with these sensory fibers) ultimately leading to contraction of inhibited muscles.

Indications of Cryotherapy:

Cryotherapy is indicated in the following conditions:
        I.            Acute injury:Cryotherapy is widely used to control acute inflammation and to accelerate recovery from injury.
o   It decreases fluid filtration into interstitium by vasoconstriction
o   It decreases inflammation
o   It reduces metabolic rate
o   It reduces pain and muscle spasm
o   Ice therapy is also applied with compression and elevation of the limb.

    II.            Acute burn:

Cooling decrease magnitude of injury by:
o   Reducing oedema
o   Reducing fluid loss
o   Reducing pain
o   Reducing further tissue injury
o   Decreasing blood volume during the 1st 48 hrs

 III.            Acute spinal cord injury:

Patient with acute spinal cord injury also improved with hypothermia. It was noted that complete destruction of the spinal cord may not occur at the initial moment but relates to self destructive process in cord.

  IV.            Decreasing spasticity:

It decreases the nerve conduction velocity. It increases the muscular contraction so applied on antagonist (process of stroking).

     V.            Reduction of fever:

Cold sponging during fever reduces the temperature.

  VI.            Tendinitis

VII.            Bursitis

VIII.            Arthritis etc


Ø  Open wound
Ø  Cardiac disease:
                                Arrhythmias, Myocardial Infarction etc
Ø  Hypersensitivity:
Raynaud’s disease (excessive vasospasm)
Cold urticaria
Ø  Peripheral vascular diseases:
Arteriosclerosis (affect artery)
Atherosclerosis (affect vein)