Cryotherapy

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Cryotherapy
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Does cryotherapy cool tissue directly?
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Cold Thermodynamics

• Transfer of heat depends on
• Heat Capacity of each material
• Enthalpy of Fusion
• Mode of Heat Transfer

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Heat capacity (Hp)

• AKA Specific Heat
• Raise 1 kg of material 1oC
• Greater Hp gt heat need to change material temp
• Ex. Ice vs Water

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Enthalpy of Fusion

• Change from solid to liquid
• Melting point
• Ex
• Gel pack
• Add heat 1 Hp
• Ice Pack
• Add heat 1 EF
• Add heat 1 Hp
• More heat absorbed by ice

Merrick et al, JAT, 2003
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Kinetic Energy Transfer

• Conduction
• Transfer of heat through direct contact (ice)
• Magnitude of transfer depends on?
• Convection
• Transfer of heat when particles move across the
  body (whirlpools)
• Radiation
• transfer of heat (energy) between two objects
  without a medium
• Evaporation loss of heat through sweating

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How do different layers of tissue become cooler?
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Domino Effect

• Modality-Skin Interface
• Skin-Superficial Layer Interface (1 cm deep)
• Superficial Layer-Deep Tissue Interface (2 cm
  deep)
• How are different layers of tissue cooled with
  different modalities?
• Merrick et al, JAT, 2003

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Magnitude of Cooling

• Skin surface
• 1 cm deep
• 2 cm deep
• Explanation
• Metabolism and perfusion
• Insulation (adipose tissue)
• Ote et al, Arch Phys Med, 2002
• Myrer et al, JAT, 2001
• Clinical Implication
• No cookie cutter treatment times

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Why do we use cryotherapy?
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• Pain Control
• Reduce Secondary Tissue Injury

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Pain Control

• Gate Control
• What afferent fiber?
• Conduction Velocities
• Pain sensory fibers
• Lee et al, Physiother, 1978
• Gamma motor neurons

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Physiologically what happens when we use cold
modalities to manage acute trauma?

• Hemodynamic Effects
• Cellular Metabolism Effects
• Neurological Effects
• Neuromuscular Effects
• Strength
• Spasm
• Neuromuscular control

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Hemodynamic Effects

• Immediate Response
• Vasoconstriction _at_ arterioles and venules
• Causes of Vasoconstriction
• Direct action on smooth muscles
• Reflexive cutaneous vasoconstriction
• Hunting Reflex
• Old term
• Describes switching VD and VC
• Have VD but overal maintai VC state

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Cellular Metabolism Affects

• Secondary Hypoxic (Ischemic) Injury
• Decrease oxygen
• Inadequate fuel substrates
• Inadequate waste removal
• Attempt to reduce Secondary Injury

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Reduced Secondary Tissue Injury
Merrick, MSSE, 1999
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Neurological Effects (Peripheral Nerves)

• Alters conduction velocities
• Decrease sensory
• Decrease motor conduction velocities
• Impeded or blocked synaptic transmission
• Sensory fibers affected first?
• A-delta and C fibers Conduction velocities
  decreased
• Larger A fiber (alpha and beta affected last)
• Gamma motor neurons also affected
• Lager A fibers and gamma motor neuron important
  in reducing spasm

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Reducing Spasm

• Muscle spindles and GTOs
• Group Ia and II fibers reduce frequency of
  discharge
• Alpha motorneuron firing decreases
• End result
• Decreased stretch reflex sensitivity

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Neuromuscular Control Effects

• Research is out
• Ensure tissue re-warmed before strenuous activity
• Re-warming of Skin
• Re-warming deeper tissues
• Re-warming should be twice that of the cooling
  time

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Strength Effects

• Short-term Exposure
• 1-5 minutes
• Effects
• Why?
• Long-term Exposure
• 20-30 minutes
• Effects
• Why?
• Clinical Significance

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Patient Sensation during Cold Application

• Cold
• Burning
• Aching
• Analgesia
• Why?

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Clinical Implications for Cryotherapy

• Acute Trauma
• Myofascial Pain
• Spasm Reduction
• Pain Relief

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Guidelines for Cryotherapy Procedures

• Choices Depends on
• Accessibility
• Body part to be treated
• Size of treatment area

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Cold Packs

• Commercial
• Storage
• Do not apply directly to skin
• Ice Packs
• Moist towels facilitate cold transmission
• Can place directly on skin

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Cold Whirlpool

• Considerations
• Gravity dependent position
• Water agitation
• Water Temperature
• Tx time
• Precautions
• Indications

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Ice Massage

• Indications
• Spasm, contusions localized injuries
• Small treatment areas
• Treatment time

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Ice Immersion

• Circumferential cooling
• Indications
• Temperature
• Precautions
• Can be used in combo with other modalities

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Other Cold Modality Methods

• Controlled Cold-Compression Units
• Vapocoolant Spray
• Cryokinetic (Cryostretch

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Contraindications to Cryotherapy

• Reynauds Phenomena
• Cold Urticaria
• Cold induced Hemogloinuria and Cryoglobinemia
• Compromised circulation or sensation

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Raynauds Phenomena
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Cold Urticaria
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Hemoglobinuria
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Precautions for Cold Therapy Usage

• Superficial Nerves
• Elevation of Blood Pressure
• Hypertensive patients only
• Wound Healing
• Psychological Consideration