Introduction to Physical Agents (week 1)

What are physical agents

energy and materials applied to patients to assist in rehabilitation.

The are also called modalities.

Physical Agents are used to:

• Modify tissue inflammation and healing

• Relieve pain

• Alter collagen extensibility

• Modify muscle tone

Stages of Healing

A) Inflammation

B) Proliferation

C) Maturation

What is edema?

is the accumulation of fluid within the extracellular space and interstitial tissues

• Transudate

• Exudate

• Pus

Pus

fluid containing neutrophils, liquefied digestion products of tissue and bacteria if an infection is present

Exudate fluid

cloudy, thicker fluid that occurs in response to minor injuries

transudate fluid

fluid that first forms during inflammation

What is Chronic Inflammation?

is simultaneous progression of active inflammation, tissue destruction and healing. Chronic inflammation may last for months or years due to persistent injury or interference with the normal healing process.

Chronic inflammation can result in the following complications:

• Increased fibroblast proliferation —> increased collagen production —> increased scar tissue and adhesion formation —> possible loss of function

Factors affecting the healing process local

Type, size and location the injury

Infection

Vascular supply

Movement/ excessive pressure

Temperature deviation

Topical medications

Electromagnetic energy

Retained foreign body

Factors affecting the healing process system

Age

Infection or disease

Metabolic status

Nutrition

Hormones

Medication

Fever

Oxygen

healing of cartilage

limited ability to heal due to lack of lymphatics, blood and neural supply

healing of bone

Stages are impaction, induction, inflammation, soft callus, hard callus, remodeling

healing of skeletal muscles

severe injury can result in a calcified hematoma (myositis ossificans)

healing of ligaments

healing is dependent on the type of ligament, size of defect and load applied; mature ligamentous repair tissue is 30-50% weaker than an uninjured ligament

healing of tendons

adhesions are more likely to develop if the synovial sheath is injured; active contraction prior to 3 weeks post injury may lead to complications

What is the connection between healing and Physical agents?

Physical Agents can be used to promote tissue healing

The stage of healing determines the goals of intervention and physical agents to be used

Always be able to connect the physiology of the injury to the physical agent being used in the treatment/POC.

Pain defintion

Unpleasant sensory or emotional experience associated with actual or threatened tissue damage

Nocioceptors are activated by intense thermal, mechanical or chemical stimuli.

When nocioceptors are stimulated, the signal is converted to an electrical activity (action potential) that travels to the dorsal root ganglia of the spinal cord.

These signals are sent to the brain through 2 types of primary afferent fibers:

• C fibers

• A-delta fibers

Physical agents can decrease pain by:

• Reducing the effect of the underlying problem (reducing edema —> signals to mechanoreceptors)

• Modifying pain transmission or perception (more on this later)

C fibers

small, unmyelinated fibers that transmit signals relatively slowly

transmits signals that are described as dull, throbbing, aching, burning

slow onset of sensation, but long-lasting

can be difficult to tolerate emotionally

sensations are often accompanied by autonomic responses such as sweating, inc. BP, nausea

A-delta fibers

small, myelinated fibers that transmit faster

respond to high-intensity mechanical stimuli, heat or cold

Quick onset of sensation, but short in duration

transmit signals that are described as sharp, stabbing, pricking

non-painful stimuli

A-beta fibers are large myelinated fibers with receptors in the skin, bones and joints that transmit sensation related to vibration, stretching of the skin and mechanoreception

What can physical agents do to decrease pain?

Inhibit pain signal to the brain with the gate control theory of pain modulation. Gate control theory of pain modulation is the theory that pain is modulated at the spinal cord by inhibitory effects of innocuous afferent input. (Ex: vibration sensation is provided to inhibit reception of pain signal).

• Endogenous opioid theory – The theory that pain is modulated at peripheral, spinal cord and cortical levels by endogenous neurotransmitters that bind to the same receptors of exogenous opioids.

Cutaneous pain

is typically well localized and sharp.

Musculoskeletal pain

is typically poorly localized and dull, heavy or aching

Visceral pain

refers superficially and has an aching quality.

The body’s response to pain

Pain-spasm-pain cycle is the cycle in which nocioceptor activation causes transmission cell activation that stimulates anterior horn cells to cause muscles to contract.

This produces compression of blood vessels, accumulation of chemical irritants, mechanical compression of the nocioceptor, and a resultant increase in nocioceptor activation.

Chronic pain

pain that does not resolve within the normal recovery time for an expected disease or injury; pain of varying levels that lasts for extended periods of time

Referred pain

pain that is referred to a musculoskeletal area from an internal organ or another musculoskeletal area

Radicular pain

pain that results from direct irritation of axons of a spinal nerve or neurons in the dorsal root ganglion an is experienced in the musculoskeletal system in a dermatome pattern.

Neuropathic pain

pain caused by a lesion or disease affecting the nerves; often described as burning; often accompanies by symptoms such as paresthesias, itching, numbness, weakness

Pain caused by malignancy

Be careful of contraindications unless being used to improve patient’s quality of life with end-stage malignancies.

Complex Regional Pain Syndrome

Believed to be the result of over activation of the sympathetic nervous system (previously RSD)

Acute pain

a type of pain that typically lasts less than 3 to 6 months, or pain that is directly related to soft tissue damage such as a sprained ankle or a paper cut.

Contraindications

Conditions under which a particular treatment should not be applied

precautions

Conditions under which a particular form of treatment may be permissible when applied with special care or limitations

contraindications/Precautions

Pregnancy

Malignancy

Pacemaker or other implanted electronic device

Impaired sensation

Impaired mentation

Selection of a physical Agent

Evidence-based practice should be utilized by the PT when including a physical agent in the POC.

Over utilization of physical agents is detrimental to the profession.

Use of physical agents that treat pain only are rarely reimbursed.

Informed Consent and Physical Agents

• Explanation of findings, description of interventions - including risks, benefits and alternatives of interventions

• Opportunity to ask questions about the examination/evaluation, diagnosis, prognosis or proposed interventions

• A formal request for permission to proceed with the plan of care