Comprehensive Overview of Cryotherapy in Physical Therapy

CRYOTHERAPY

lecture content • Cryotherapy• Effects of Cold • Clinical Indications for Cryotherapy • Contraindications for Cryotherapy • Precautions for the Use of Cryotherapy • Adverse Effects of Cryotherapy

• Cryotherapy, the  therapeutic use of  cold . 

• In PT, cryotherapy is used to control  inflammation ,  pain,  and  edema;  to  reduce  spasticity;  to  control  symptoms of  multiple sclerosis ; and  to facilitate movement. 

Spasticity • Pathological increase  of tone • An increased  rigidity  of muscles due to brain or spinal cord injury.

Initial Decrease in Blood Flow This vasoconstriction persists as long as the duration of the cold application is limited to less than 15 to 20 minutes.

Effects of Cold Hemodynamic Effects 

Initial Decrease in Blood Flow(Cont.) 

body reduces blood flow It is thought that the body reduces blood flow in response to decreased tissue temperature to protect other areas from excessive cooling and to stabilize core body temperature.  so  Vasoconstriction occurs first to reduce heat loss  The less blood that flows through an area being cooled, the smaller volume of blood that is cooled, and the less other areas in the circulatory system are affected

Later Increase in Blood Flow  • When cold is applied for longer periods of time or when the tissue temperature reaches less than 10°C (50°F), vasodilation may occur. This phenomenon is known as cold-induced vasodilation (CIVD)

cold-induced vasodilation (CIVD) When cold is applied for longer periods of time or when the tissue temperature reaches less than 10°C (50°F), vasodilation may occur. This phenomenon is known as  cold-induced vasodilation (CIVD)  and  was first reported by Lewis in 1930, Lewis correlated this temperature cycling with alternating vasoconstriction and vasodilation and called this the  hunting response .  It is generally recommended that cold be applied for no more than 15 minutes, particularly when the distal extremities are treated.

Cold-induced vasodilation (CIVD) hunting response  Although the increase in skin  redness  seen with the application of cold  may appear to be a sign of CIVD, this change is actually thought to be primarily the result of an increased concentration of  oxyhemoglobin  in  the blood caused by a decrease in  oxygen-hemoglobin dissociation  that  occurs at lower temperatures . Because cooling decreases oxygen-hemoglobin dissociation, making less oxygen available to the tissues, CIVD is not an effective way to increase oxygen delivery to an area.

Neuromuscular Effects  • Decreasing nerve conduction velocity,  • Elevating the pain threshold,  • Altering muscle force generation,  • Decreasing spasticity,  • Facilitating muscle contraction.

Decreased Nerve Conduction Velocity  • Although decreased nerve conduction velocity can occur if a superficial cooling agent is applied to the skin for 5 minutes or longer, it fully reverses within 15 minutes in individuals who have normal circulation.  • However, after 20 minutes of cooling, nerve conduction velocity may take  30 minutes  or longer to  recover  as a result of the greater reduction in  temperature caused by the longer duration of cooling

Reduced Pain and Increased Pain Threshold  • Increase the pain threshold.  • Decrease the sensation of pain.  • “counterirritation via the gate control mechanism and reduction of muscle spasm, slowing of sensory nerve conduction velocity, or reduction of postinjury edema”.

Altered Muscle Strength  • Depending on the duration of the intervention and the timing of measurement,  • Cryotherapy has been associated with both increases and decreases in muscle strength. 

• Depending on the duration of the intervention and the timing of measurement,  • Cryotherapy has been associated with both increases and decreases in muscle strength.  • Isometric muscle strength has been found to increase directly after applying ice massage for 5 minutes or less.  • Proposed mechanisms for this response to brief cooling include facilitation of motor nerve excitability.

Altered Muscle Strength (Cont.)  • In contrast, after cooling for 20 minutes or longer, isometric muscle strength decreases immediately after cooling,  • This initial reduction in performance may reverse 1 hour later, when strength may be greater than precooling measures for the following 3 hours or longer . 

Altered Muscle Strength(Cont.)  • Proposed mechanisms for reduced strength after  prolonged cooling include reduced blood flow to  the muscles, slowed motor nerve conduction,  increased muscle viscosity. • Therefore, it is recommended that muscle  strength be consistently measured before the  application of cryotherapy and that precooling  strength not be compared with post cooling  strength in attempts to assess patient progress. 

Decreased Spasticity  • A reflex reaction to stimulation of cutaneous cold receptors causing a reduction in gamma motor neuron activity. After more prolonged cooling of 10 to 30 minutes.  • decreased discharge from afferent spindles and Golgi tendon organs (GTOs) as a result of decreased muscle temperature.  • These later effects generally persist for 1 to 1.5 hours and therefore can be taken advantage of in treatment by applying cryotherapy to hypertonic areas for up to 30 minutes before employing other interventions to reduce spasticity during functional or therapeutic activities.

Decreased Spasticity 

Facilitation of Muscle Contraction  Brief application of cryotherapy is thought to facilitate alpha motor neuron activity to contract a muscle that is flaccid because of prolonged upper motor neuron dysfunction. This effect is observed in response to a few seconds of cooling .

Metabolic Effects  • Cold decreases the rate of all metabolic  reactions, including reactions involved in  inflammation and healing. •  Thus, cryotherapy can be used to control acute  inflammation.  • The activity of cartilage degrading enzymes  such as collagenase, elastase, hyaluronidase,  and protease and the level of histamine are  reduced by decreases in joint temperature. 

Clinical Indications for Cryotherapy  • Inflammation Control It control acute  inflammation, accelerating recovery from injury  or trauma.  • Decreasing tissue temperature slows the rate of  chemical reactions that occur during the acute  inflammatory response and reduces the heat,  redness, edema, pain, and loss of function  associated with this phase of tissue healing. 

Cont. Clinical Indications for Cryotherapy  • Thereby reducing bleeding and fluid loss after acute trauma.  • Cryotherapy is thought to reduce pain by decreasing the activity of A-delta pain fibers and by gating at the spinal cord level. •  Controlling the edema and pain associated with inflammation limits the loss of function associated with this phase of tissue healing.

Inflammation Control(Cont.) • Apply cryotherapy immediately after injury and during the acute inflammatory phase of healing to help control bleeding, edema, and pain and to accelerate recovery; therefore, the sooner the intervention is applied, the greater and more immediate are the potential benefits. 

• To limit the possibility of excessive decreases in tissue temperature and resultant cold-induced injuries, cryotherapy applications should be at least 1 hour apart so that the tissue temperature can return to normal between treatments.  • When using cryotherapy to control inflammation on the extremities, apply for no longer than 15 minutes at least 1 hour apart.

Edema Control  • Cryotherapy can be used to reduce edema, particularly edema associated with acute inflammation. During acute inflammation, edema is caused by increased intravascular fluid pressure and vascular permeability that extravasate fluid into the interstitium. 

• Cryotherapy reduces this intravascular pressure by reducing the blood flow into the area through vasoconstriction and increased blood viscosity. Cryotherapy also controls increases in capillary permeability by reducing the release of vasoactive substances such as histamine.

Edema Control(Cont.) PRICE   P protectionRICE     R rest             I ICE application              E Elevation              C compression

Edema Control(Cont.) • To most effectively minimize edema formation, cryotherapy should be  applied as soon as possible after acute trauma in conjunction with compression using an elastic wrap and elevation of the affected area above the level of the heart. •  Compression and elevation reduce edema by pushing extravascular fluid out of the swollen area and into the venous and lymphatic drainage systems.  • The acronym RICE refers to the combined intervention of rest, ice, compression, and elevation.  • Although cryotherapy can reduce edema associated with acute inflammation, it is not effective in controlling edema caused by immobility and poor circulation. 

Pain Control  • The decrease in tissue temperature produced by cryotherapy may directly or indirectly reduce the sensation of pain. Cryotherapy directly and rapidly modifies the sensation of pain by gating pain transmission through the activity of cutaneous thermal receptors. 

Pain Control(Cont.)  • Applying cryotherapy for 10 to 15 minutes or longer  can control pain for 1 hour or longer.  • This prolonged effect is thought to be the result of  blocking conduction in deep, pain-transmitting A  delta fibers and by gating pain transmission by  cutaneous thermal receptors. •  The effect is thought to be prolonged because the  temperature of the area remains lower than normal  for 1 or 2 hours after the cooling modality is  removed.

• Reducing pain through cryotherapy can directly interrupt the pain spasm-pain cycle by alleviating the muscle spasm and pain even after the temperature of the treated area has returned to normal. Cryotherapy can also reduce pain indirectly by controlling its underlying cause, such as inflammation or edema

Modification of Spasticity  • Longer applications of cryotherapy can control more of the signs of spasticity, cryotherapy should be applied for up to 30 minutes when this is the goal of the intervention.  • The decrease in spasticity produced by prolonged cooling generally lasts for 1 hour or longer after the intervention; 

Symptom Management in Multiple Sclerosis  • Some patients with multiple sclerosis are aggravated by generalized heating such as occurs in warm environments or with activity. •  Cooling can reduce fatigue, muscle weakness, and postural instability in patients having heat sensitive multiple sclerosis

Facilitation  • Rapid application  of ice as a stimulus to elicit  desired motor patterns, known as  quick icing , is  a technique developed by Rood.  • This technique may be used effectively in the rehabilitation of patients with flaccidity resulting from  upper motor neuron dysfunction .

Cryostretch  • Cryostretch is the application of a cooling agent before stretching. •  The purpose of this sequence of treatments is to reduce muscle spasm, thus allowing greater ROM increases with stretching.

Contraindications for Cryotherapy  • Cold hypersensitivity (cold-induced urticaria)

Contraindications for Cryotherapy  • Cryoglobulinemia

Contraindications for Cryotherapy  •  Paroxysmal cold hemoglobinuria  •  Raynaud disease or phenomenon  •  Over regenerating peripheral nerves  •  Over an area with circulatory compromise or peripheral vascular disease

Precautions for the Use of Cryotherapy  • Over the superficial main branch of a nerve  • Over an open wound  • Hypertension  • Poor sensation or mentation  • Very young and very old patients

Adverse Effects of Cryotherapy  • The most severe adverse effect is tissue death caused by prolonged vasoconstriction, ischemia, and thromboses in the smaller vessels.  • Tissue death may also result from freezing. Damage can occur when the tissue's temperature reaches 15°C (59°F). 

• N.B.: Cool cold packs for at least 2 hours  before initial use and for 30 minutes  between uses.