pm& r lecture series

PM& R Lecture Series

Therapeutic Physical Agents

Physical Medicine the application of physical agents

such as: heat cold sound water electricity and other mechanical

agents

in the treatment of disease.

Therapeutic Heat Physiologic Effects:

Increase of 3oC increases collagenase activity

Heating hands to 450C reduces MCPJ stiffness by 20%

Changes of 5-7oC alter blood flow and collagen extensibility

Hot paraffin increases local skin temp by 7.5oC and intraarticular temp by 1.7oC

Therapeutic Heat

A n a lg e s ia(h e a t s e rv e s a s c o u n te r-

ir r ita n t to p a in o n ne rv e s)

S e d a t io n

M u s c le R e la x a t io n(d e c f ir in g o f -s p in d le

f ib e r )

c le a r in g o fh e a t & m e ta b o lis m

s u p p ly o f O 2 ,n u t r ie n ts ,

le u k o c y te s

in c . in c a p illa ry f lo w

e d e m a(why heat not applied

im m e d ia te ly a f te rt ra u m a t ic in ju ry )

inc. in cap illary pressure

a r te r io la r d ila ta t io n

in c . in m e ta b o lis m(d u e to h e a t -p ro d u c e d

m etabo lite s like h is ta mine)

In c . in te m p e ra tu re

H E A T

Therapeutic Heat Indications

relief of pain relief of spasm increased exetensibility of collagen tissue (e.g.

fractures/contractures) decreased joint stiffness (OA, RA) increased blood flow

* remember, the physiologic effects of heat manifest themselves only if the heat is applied for at least twenty minutes at a temperature of 40-45o C.

General Indications Pain Muscle spasm Contracture Tension myalgia Production of

hyperemia Acceleration of

metabolic process Hematoma

resolution

Bursitis Tenosynovitis Fibrositis Fibromyalgia Superficial

thrombophlebitis Induction of reflex

vasodilatation Collagen vascular

disease

General Contraindications Acute inflammation,

trauma or hemorrhage Bleeding disorders Cutaneous insensitivity Inability to

communicate or respond to pain

Poor thermal regulation

Malignancy

Edema Ischemia Atrophic skin Scar tissue Unstable angina or

blood pressure Decompensated

heart failure within 6 to 8 weeks of an MI

mode of transfer heating modality depth of penetration

1. conduction (by direct contact)

hot packsparaffin

superficial

2. convection (via a medium in motion such as air, water)

hydrotherapyfluidotherapy

superficial (reaches skin and muscle)

3. conversion (actual conversion of a different form of energy to heat)

shortwave diathermymicrowaveultrasound

reaches area of ligaments, tendons, osseous structures

Hot Moist Packs applied at a temperature

of 46oC stays warm for twenty

minutes or more inc blood flow by as

much as 68% sacks filled with silica

gel (expensive) blood flow doesn’t return

to resting level until 40 mins. after cessation

for analgesia and muscle relaxation

Paraffin Wax Bath applied at a temperature of

45-54oC solution contains 1 part

mineral oil (useful for those whose skin had undergone trophic changes) to 7 parts paraffin (can be tolerated by px with sensory deficits)

higher temperature is tolerable without the risk of burns (due to high specific heat of paraffin)

commonly used on the hand and wrist and other uneven surfaces

Paraffin Wax Bath Dipping technique

Immerse part 6-10 times to build up layers of paraffin

Followed by wrapping extremity with an insulating cover

Skin temp achieved: 47oC Subcutaneous temp change

of 3oC Intraarticular temp change of

around 1oC Continuous immersion

Dipped 6-10 times, then kept immersed for 20-30 mins

Subcutaneous temp change of 50C

Intraarticular temp change of 3oC

Infrared Radiation Uses that portion of the EMS

from 7700-150000 A Maximum penetration of 3mm

(superficial) Dry heat (less comfortable) Commonly used to decrease

skin resistance by inc. blood flow (e.g. in Bell’s palsy)

Wound healing and other dermatological conditions (dries up wound but has no other effects unlike UV light)

Heat inversely proportional to distance and angle of delivery

Usual distance about 40-50 cm and perpendicular to surface treated

Hydrotherapy

applied at a temperature of 33-43oC

full body immersion can increase core temp by 0.3oC

heat and exercise can be done at the same time

bouyancy effect permits easier movement of weak or painful extremities

agitation of medium permits gentle debridement (e.g. for burns)

Fluidotherapy

Convection heating modality

Uses cellulose particles suspended in jets of warm air

Contrast Bath One bath at 38 to 40oC The other bath at 13 to 16oC Produces reflex hyperemia and

neurologic desentisization Initial soaking in warm bath for

10 mins Followed by 4 cycles of alternate

1 to 4 minute cold soaks and 4-6 minute warm soak

Ends with cold soak to minimize edema

Used in treatment of CRPS type I (RSD)

Ultrasound Diathermy

involves conversion of sound waves at a frequency faster than 17000-20000 cycles/sec

applied to tissues causing mechanical vibration which dissipates heat

deepest penetrating agent; only agent that can significantly heat the hip jt. (by 8-10oC)

both thermal and nonthermal effects


Nonthermal effects Cavitation

US travelling through liquid produces bubbles which oscillate in size

Streaming Produces shear forces in

tissue that may accelerate metabolic processes

Standing waves Produces areas of

alternating high and low pressure


Penetration dependent upon: Type of tissue Frequency (usually

1 or 3 MHz) Angle of orientation

Ultrasound Half Value Depth in Millimeters

Medium 1MHz 3MHzAdipose tissue 50.0 16.5

Skeletal muscle (fibers parallel to sound beam)

24.6 8.0

Tendon 6.2 2.0

Skin 11.1 4.0

Skeletal muscle (fibers perpendicular to sound beam)

9.0 3.0

Cartilage 6.0 2.0

Compact bone 2.1 _

Kitchen and Bazin(1996) Clayton’s Electrotherapy 10th ed.


Indications Musculoskeletal

conditions (tendinitis, arthritis, patellofemoral pain)

Contractures Wounds and

inflammation Trauma (subacute phase) Fractures


Contraindications Fluid filled cavities (eyes,

gravid uterus) Spinal cord, esp laminectomy

sites Immature bone (e.g.

children) Heart, brain, cervical ganglia Metal implants Methylmethacrylate implants

(plastics, bone cement) Acute inflammation

Injury

General Musculoskeletal Disorders:

Muscle spasmJoint stiffness

Pain

Tissue Repair:Soft tissue repair

Stimulation of blood flowBone fracture repair

Tendon repair

THERMAL EFFECT

CONTINUOUS WAVE

NON-THERMAL EFFECT

PULSED WAVE

Shortwave diathermy involves conversion of

radiofrequency EM current into heat energy

commonly uses 27.12 Mhz uses condenser pads, plates

and internal metal electrodes for heat transfer (not very convenient)

penetration between skin and subcutaneous tissue

Can heat larger areas than ultrasound

Shortwave diathermy Inductive applicators

Generate magnetic eddy currents in tissue

Highest temperature in water rich, highly conductive tissue (e.g. muscle)

Capacitively coupled applicators

Generate electrical fields Highest temperature in water

poor tissue like fat, ligament, tendon or joint capsules

May be pulsed or continuous

Microwave diathermy

Uses 915 and 2456 MHz

Does not penetrate as deeply as SWD or US

Highest temperatures are achieved at the fat-muscle interface

Therapeutic Cold

Decreases collagenase activity Cooling hands to 180C increases MCPJ

stiffness by 20% Icing an acutely inflamed knee

Decreases skin temp by 160 C Decreases intraarticular temp by 5-60

C

Therapeutic Cold

a n a e s th e s ia

reflex v asodilatation(a f te r 3 0 m in s )

v a s o c o n s t r ic t io n( f irs t 5 -1 5 m in s )

d ecre ase in m eta bolism re la x a t io n(d e c f ir in g o f -s p in d le

f ib e rs )

C O L D

* cold can also stimulate a-motor neurons and cause muscles to contract rather than relax

General Indications Acute musculoskeletal trauma

Edema Hemorrhage Analgesia

Pain Spasticity Adjunct in muscle reeducation Reduction of local and systemic

metabolic activity

General Contraindications Ischemia Cold intolerance Raynaud’s phenomenon or disease Severe cold pressor responses Cold allergy Inability to communicate or respond to pain Poor thermal regulation Cutaneous insensitivity

Therapeutic Cold

Modalities ice packs cryogel packs ice immersion ice cube ethyl chloride spray

ElectrotherapyTranscutaneous Electrical Nerve

Stimulation (TENS) two theories:

gate control theory: electrical stimulus carried through large -

fibers which arrive at the substantia gelatinosa before the pain impulses traveling through the c-fibers.

treatment is effective only during application. endorphin stimulation:

TENS stimulates production of natural analgesics.

Treatment is effective even after cessation.

Electrotherapy high frequency, low

intensity stimulates large diameter

afferent fibers Low frequency, high

intensity endorphin stimulation

Other Modalities

Low power laser Not a heating modality Stimulates collagen

production, alters DNA synthesis, improves function of damaged nerves

FDA approved for CTS, neck, and shoulder pain

Other Modalities

UV light no heating function uses part of EMS between 1800-

2900 angstroms dose is determined by testing

called Minimum Erythemal Dose (MED); erythema should appear w/in 30 mins- 1 hr and disappear after 24 hrs.

penetration does not exceed 0.1 mm

bactericidal (helps wound healing)

anti-rachitic (vit. D formation Anti-psoriatic

Thank you!

pm& r lecture series

Documents