1. Therapeutic Heating Modalities
Mohammed Taher Ahmed
Mobile :
Office number: 2074

2. Objectives After studying this lecture, the students must be able to;
Define the therapeutic modalities.
Differentiate between methods of heat transfer.
Understand the physiological effects of thermotherapy.
Offer guidelines for use of therapeutic modalities.

3. Outlines Classification of therapeutic modalities
Methods of heat transfers
Physiological effects of thermotherapy.
Uses (indications ) of thermotherapy.
Contraindications of thermotherapy.
Precautions & dangerous of thermotherapy

4. Therapeutic Heating Modalities
Therapeutic heating modalities are a variety of physical agent used to deliver therapeutic heat, [( F)/(40-450C)], aiming to produce physiological reaction that induces therapeutic benefits.
Its lower limit is greater than the average basal temperature of soft tissue and its higher limit is less than lethal thermal value .

5. Classification of Therapeutic Modalities
Electromagnetic Energy Modalities
Diathermy
Shortwave Diathermy (SWD)
Microwave Diathermy (MVD) ,
Actinotherapy Modalities
Infrared radiation (IR)
Ultraviolet therapy (UV)
Low level Laser Therapy (LLLT)
Paraffin wax
Hot packs and hydrocollator
Acoustic Energy Modalities
Ultrasound (US)
Extracorporeal Shock wave therapy (E
Diathermy (SWD+MWD)
Light therapy (Laser+ UV+IR) or radiation therapy (IR+Laser)
Sound therapy (US+ESWT)

6. Classification of Therapeutic Modalities
Superficial Heating Modalities
Hydrocollator packs,
Whirlpool,
Paraffin wax,
Infrared lamp
Fluidotherapy
Depths to cm .
Deep Heating Modalities
Shortwave diathermy,
Microwave diathermy,
Ultrasound,
Laser
Depths to 3-5 cm
Superficial and Deep heating agents increase the skin temperature within the therapeutic range of 104°F to 113°F in order to provide physiological effects for therapeutic benefite.

7. Classification of Therapeutic Modalities

8. Methods of Heat Transfer
Heat can be transferred to, from, or within the body tissues by:
Radiation
Conduction
Convection
Conversion
Evaporation

9. Methods of Heat Transfer
Conduction is a direct transfer of energy between two objects in physical contact with each other. Energy is transferred from the area of higher temp, to the area of low temp.
Ice packs/bags
Hot packs
Paraffin
Ultrasound
Rate of energy transfer by conduction is dependent on
Temperature difference between two materials
Thermal conductivity
The total contact area
Tissue thickness

10. Methods of Heat Transfer
Radiation is a direct transfer of energy from higher temperature to lower temperature without the need for an intervening medium. No-contact is made.
Shortwave diathermy
Microwave Diathermy
Infrared
Ultraviolet therapy
Rate of heat transfer Radiations
Intensity of radiation
Size of radiation source
Types of tissue radiated
Distance from radiation source
Angle of incidence

11. Methods of Heat Transfer
Convection is a transfer of heat through direct contact between circulating medium (air/ water) and another material of different temperature .
This is in contrast to heating by conduction, in which there is constant contact medium between objects.
Fluid therapy
Whirlpools
Blood circulation

12. Methods of Heat Transfer
Conversion is a conversion of non-thermal form of energy (mechanical, electrical and / or chemical) into heat.
Change of one form of energy to another
Electromagnetic energy to heat
Acoustical energy to heat
Heat transfer by conversion does not require direct contact between the thermal agent and the body, however contact medium is required.
Ultrasound
Microwave
Shortwave.

13. Methods of Heat Transfer
Evaporation: heat is absorbed by the liquid on the skin surface and cools the skin as it turns into a gaseous state.
Vapocoolant sprays
Alcohol
Sweating

14. Factors Affecting Energy Transfer
Density of Medium
Reflection
Refraction
Absorption
Law of Grotthus-Draper
Cosine law
Inverse Square Law E=Eo/D²

15. Bio-Physiological Response to Thermotherapy
Hemodynamic effects II
Neuromuscular effect
III
Tissue Extensibility IV
Metabolic effect

16. I-Hemodynamic Effects
Vasodilatation – Increase in blood flow:
Effect occurs both locally and systemically
Vasodilatation occurs by variety of methods:
Direct action on smooth muscles of the blood vessels by cutaneous thermo-receptors
Indirect activation of spinal cord reflexes
Increasing the local release of chemical mediators.
This phenomenon can be used to increase blood flow to an area where heat is not able to be applied e.g.
Insensate limb
Ulcer on the leg

17. Hemodynamic Effects

18. II-Neuromuscular Effects
Heat provides analgesia to relief pain and muscle spasm
Elevate pain threshold (closing of gate control mechanism and enhance secretion of endorphins to block pain and free nerve endings).
Indirect by reduction of ischemia and muscle spasm .
Increase nerve conduction velocity
Decrease conduction latency).
Change muscle spindle firing rates
Changes in muscle strength
Muscle strength and endurance found to decrease for initial 30 minutes following heat application
Gradually recovers then increases for next 2 hours
Not really used therapeutically but should keep in mind if measuring muscle strength in therapy

19. III-Altered Tissue Extensibility
Increased Extensibility of Collagen (40-45°C )
Increase extensibility of collagen (tendon, ligament, capsule ) resulting in
Relaxation of tension,
Increase length of soft tissue,
Increase ROM
Superficial heat alone will NOT alter viscoelastic properties of tissue
Heat + Stretch
Result = plastic elongation of deeper tissue such as (tendons, ligaments, joint. capsule, fascia ).
Factors important determining treatment strategies
Temperature elevation (40-45°C )
Time must be maintained for 5-10 minutes.
Stretch exercises
Superficial agents only good for small superficial joints,
Deep agents required for deeper large joints, capsules, muscles.

20. Increase IV-Metabolic Effects Metabolic rate Enzymatic activity
For every 18°F (10°C) increase in skin temperature
“the metabolic rate increased by factors of 2-3” this lead to
Increase
Metabolic rate
Enzymatic activity
Capillary permeability
Local blood flow due to vasodilatation
Cell metabolism (anabolic & catabolic)
Increase leukocyte delivery
O2 uptake
At temps > 133°F, protein, cells and tissues are destroyed.

21. Physiological effects of Heat Application
Increased
1- Local blood flow
2- Lymphatic drainage
3-Capillary permeability
4-Metabolic rate
5-Cellular oxidation
6-Flexibility of collagen tissues
7-Respiratory rate
8-Cardiac output
9-Pulse rate
Decreased
1-Joint stiffness
2-Pain &muscle spasm
3-Muscle torque
4-Blood supply to internal organs
5-Blood pressure
6-Stroke volume
(1-6)-----Local effects
(7-9)-----systemic effects
(1-3)---- Local effects
(4-6)---- systemic effects

22. Use of Thermotherapy
Indication: A condition(s) that could benefit from a specific therapeutic modality.
Contraindication: A condition(s) that could be adversely affected if a particular therapeutic modality is used.
Precautions:
Applied with special care or limitations.
“Relative contraindications”

23. General Indications (uses)
Subacute or chronic inflammatory conditions
Reduction of subacute or chronic pain
Subacute or chronic muscle spasm
↓ ROM
Hematoma resolution
Reduction of Joint contractures
Before passive mobilization and exercise

24. General Contraindications
Acute injuries
Recent or potential hemorrhage
Impaired circulation (Chronic venous insufficiency )
Poor thermal regulation (neuropathic foot/hand)
Over or around neoplasms
Over or around infected area(

25. Precautions to Thermotherapy
Never apply heat directly to eyes or the genitals.
Never heat the abdomen during pregnancy.
Very young and very old patients.
Mental retard patients.
Cardiac insufficiency.
To areas with metal implants (higher thermal conductivity)
Over area of topical anesthesia or counterirritants have r been applied
Dermatological anomalies.

26. Adverse Affects of Heat
Burns due to:
Poor technique
Patients' inability to dissipate or detect heat
Treatment over areas of implanted metal or open wounds
Bleeding: In acute trauma or hemophilia
Fainting: Due to potential peripheral superficial vasodilatation and decrease blood pressure .

27. MCQ- Questions 1-Hemodynamic - Neuromuscular - Metabolic
Biophysiological Effects
Metabolic Effects
Neuromuscular Effects
Hemodynamic Effects
2-Increases nerve conduction velocity - increases collagenous tissue extensibility - increases pain threshold - decreases muscular strength
3-Hot packs - Fluidotherapy - Paraffin - Whirlpool - SW Diathermy - US
Therapeutic Dosage
Hemodynamic Effects
Deep Heat Modalities
Types of Thermal Agents