Electrotherapy II

Ass.Prof.Manar Azab

Percutaneous Electrical Nerve Stimulation(PENS)

Refers to applying electrical stimulation through small

needles which penetrate the skin. needle electrodes deliver current closer to the nerves or the muscles beneath the skin,

making the nerves less sensitive to pain

Percutaneous electrical nerve stimulation (PENS) combines

advantages of electroacupuncture and TENS. Rather than using

surface electrodes, PENS uses acupuncture-like needle probes as

electrodes, with these placed at dermatomal levels corresponding

to local pathology.

The main advantage of PENS over TENS is that it bypasses local skin resistance and delivers electrical stimuli at the precisely desired level in close proximity to the nerve endings located in soft tissue, muscle, or periosteum

PENS machine delivers low voltage electrical current to the peripheral nerves via probe(s) placed just

under the skin. It works by altering the state of the nerves resulting in pain

relief. It does not destroy the nerves but makes

them less sensitive to pain.

Indications

Chronic nerve pain, as hypersensitivity, neuropathic headache and chronic post-

surgical pain.

Diabetic peripheral neuropathy

Overactive bladder syndrome

Overactive Bladder syndrome (OAB)

defined as urgency to void, that may be

accompanied by frequency and

nocturia , with or without urge urinary

incontinence.

percutaneous tibial nerve stimulation

(PTNS) ) for the treatment

overactive bladder syndrome by

stimulating the tibial nerve near the ankle

and altering the function of the

sacral nerves that control bladder

function.

PTNS sessions once weekly comprising bilateral tibial nerve stimulation, each

session lasting 30 minutes.

Amplitude is slowly increased until the patient’s large toe starts to curl, the toe digits fan out, or the entire foot extends, indicating proximity to the nerve bundle.

The stimulator produces an adjustable electrical pulse that travels up to the

sacral nerve plexus via the tibial nerve. Amplitude is then reduced slightly and treatment is continued for 30 minutes

Skeletal Muscle Affection

Muscle contraction is the activation of tension-generating sites within muscle fibers

In physiology, muscle contraction does not necessarily mean muscle shortening because muscle tension can be produced without changes in muscle length, such as

when holding a heavy book or a dumbbell at the same position

The termination of muscle contraction is followed by muscle relaxation, which is a return of the muscle fibers to their low tension-generating state

Muscle contractions can be described based on two variables: length and tension

A muscle contraction is described as isometric if the muscle tension changes but the muscle length remains the same

In contrast, a muscle contraction is isotonic if muscle tension remains the same throughout the contraction

If the muscle length shortens, the contraction is concentric; if the muscle length lengthens, the contraction is eccentric

The sliding filament theory explains the mechanism of muscle

contraction based on muscle proteins that slide past each other to generate movement. According to the sliding filament theory, the myosin (thick)

filaments of muscle fibers slide past the actin (thin) filaments during

muscle contraction

Muscle contraction begins when the nervous system

generates a signal. The signal, an impulse called

an action potential, travels through a type of nerve cell

called a motor neuron

It consists of four phases;

hypopolarization, depolarization, overshoot, and repolarization

Electromyography(EMG)

Electrotherapy for Muscles

Interrupted Direct

Current

Interruption is the most usual modification of direct current,

the flow of current

commencing and ceasing at

regular intervals, the rise and fall of intensity may

be sudden or gradual.

Faradic Current (Faradism)

Short duration interrupted

direct current with a pulse

duration ( 0.1 to 1 (50 to 100

Hz)

Surged to produce tetanic contraction and

relaxation of the muscle

Cause contraction and relaxation only in innervated

(nerves intact) muscles.

Faradic also stimulate the sensory nerve

result in pricking

sensation

The stimulated nerve causes a reaction in the

motor fibers which makes the muscle

contract

Trapezoidal surging - the impulse increases gradually followed by a gradual decrease. This is used in

mild to moderate injuries.

Triangular surging - forms

traingularsurging.

Sawtooth surging - the impulse increases gradually then suddenly falls. This is

used in severe injuries.

Stimulation of Motor Points

The indifferent electrode is applied

and secured in a suitable area. the active electrode is

placed over the motor point of the muscle to

be stimulated

Then the intensity of the current is

gradually increased until a good muscle

contraction is obtained at minimum point of each surge, then the surging is

continued to produce alternate contraction and relaxation of the

muscle

Motor point is frequently at the

junction of the upper and middle one-thirds of fleshy belly of the

muscle, e.g., the extensors hallucis

longues in the lower one third of the lower

leg

Faradic currents are always surged for

treatment purpose to produce a near-normal tetanic-like contration

and relaxation of muscle

The duration of surges and the intervals

between them should be regulated by

separate controls to get the most satisfactory

muscle contraction and rest periods for each

patient

Galvanic current

Interrupted direct current

with frequency 30 Hz & pulse

duration 1Ms and more.

Used for muscle

exposed toinjury of the

nerve.

Denervated muscle respond to

galvanic stimulus because long pulse duration and not

respond to faradic stimulus as pulse duration is short.

Types of galvanic waveforms

Rectangular surging: the current turns on

and off intensity abruptly.

Trapezoidal surging: its slow rise and slow

fall.

Triangular surging: it raises slowly,

plateau’s and then falls slowly.

Saw tooth surging: the gradual rise of

current and abruptly falls

Galvanic Iontophoresis is the use of galvanic current on the positive polarity

pushing active substances into the skin

for moisturizing, soothing, decongesting,

and detoxifying purposes. Iontophoresis

helps improve skin texture by tightening and firming, refines

pores, reduces redness and soothes nerve

endings.

Physiological Effect of Direct Current

Increase blood flow to the area treated causing redness due to vasodilatation.

Increase metabolism and remove

waste product

Electrical stimulation will

re-educate muscle

Help in minimize the

extent of muscle atrophy.

Indications of Direct Current Therapy

Facilitation of muscle contraction when inhibited by Pain.

Muscle re-education:to restore the sense of movement.In cases of flat foot or in

muscle transplantation.the brain appreciate movement

Training of new muscle action.

Improved venous and lymphatic drainage as edema and gravitational ulcer by

pumping action of muscle contraction and relaxation.

Prevention and loosening of adhesion.

. Contraction of denervated muscle. For example, use of galvanic current in foot drop

Iontophoresis and analgesia with the stimulation simultaneous application of certain medicines will facilitate better

penetration of medicine.

Contraindications of Direct Current Therapy

certain dermatological condition as psoriasis ,tinea and eczema.

Inflammation

Thrombosis, thrombophlebitis and hemorrhagic conditions

Loss of sensationCancer, recent radiotherapy

Cardiac pacemakers& arrythmias

Infected wound and skin lesion

Practical Guidelines

The patient is positioned so

that part to be treated is supported

The skin surface examined for

cuts or abrasions, should be

washed by hot water to remove

sebum and epithelial cells to lower resistance.

Size of active electrode is chosen to

considering size of treatment

area.

The electrode should be smaller

than the pad to prevent the edge of the electrode being bent down

on the skin.

The pads should be soaked in

warm tap water, saline or sodium

bicarbonate solution before applied to the

skin.

Fixation is achieved with

rubber strap or by body weight.

Types of Electrode

1) Metal Plate Electrodes – early version, limited sizes, required wet sponge conduction medium, difficult to secure in place

2) Carbon – Impregnated Rubber Electrodes – degrade over time and become non-uniform with “hot spots”, many shapes and sizes, rinse and dry after each use and replaced every 12 months to ensure conductivity.

3) Self-Adhering or Single use Electrodes – flexible conductors, convenient application, no strapping or taping to keep in place

Electrode Size and Current Density

• Current density is the concentration of current under an electrode.

• Surface area is inversely proportional to current flow. (Larger electrode = current is less dense as it is distributed over a larger area and vice versa.

• Keep the electrode in proportion with size of body area being treated.

• Completing the Circuit – an electrical stimulation treatment must include a full circuit. To complete the circuit, there must be:

A source of energy creating an electrical potential difference

A conductive pathway – including electrodes, leads, and a conductive surface with good contact

Cleaning the patient’s skin with alcohol to remove oil and dirt before electrode application

Clipping excess body hair under electrodes

Minimize warming the treatment area of the body prior to stimulation so there is minimal increased resistance

Electrode Configuration

1.Monopolar – always two poles: cathode (-) is active and produces cell depolarization. Produces a net charge

2.Bipolar – two electrodes in a single circuit; each electrode alternates between positive and negative; electrodes are of equal size; no net charge is produced.

Patient will feel excitatory response under both electrodes, eliciting motor response or electrode placed over motor point, other electrode over muscle belly and may be larger

3.Quadripolar – four electrodes in two circuits that operate independently, yet interact

Interferential, large area, pain management, sensory stimulation of larger fiber

Different Wave forms

Direct current/mono phasic currentHave only single phaseCurrent flow in unidirectionalFlow in same direction towards positive or negative pole

Alternating current/biphasic currentHave two separate phasesCurrent flow is bi -directionalWave form may be symmetrical or asymmetrical

Wave form shapeCould be of any type like sine, rectangular or triangularDepends on the capabilities of the generator

Pulse amplitudeMagnitude of currentThe peak current is the maximum

amplitude of the currentMaximum amplitude of pulse can be

shown by tip of highest point of each phase

Pulse frequencyNumber of pulses per secondAs frequency of wave form is increased

the amplitude tends to increase & decrease more rapidly

Different Wave FormsPulse durationLength of time that current is flowing in one cycle

Current Modulation:

Continuous modulation

amplitude of the current remains the same for several seconds or minutes

Interrupted modulation

current flows for some period called on-time & periodically turned off during off time

Burst modulation

occurs when pulsed current flows for a short duration & in a repetitive cycle

Ramping modulation

also called surging modulation

current increases gradually or decreases gradually in its intensity

Other Electrotherapy Types

Anodyne Therapy

Anodyne therapy is a noninvasive, painless therapy that uses infrared light for the treatment of pain, numbness and decreased circulation as a result of peripheral neuropathy (weakness, numbness and pain from nerve damage, usually in the hands and feet.

How Does Anodyne Therapy Work?

Anodyne Therapy uses infrared light emitting diodes (LEDs) which penetrates more deeply into the body and works better than red or blue light.

Bodies respond to infrared with increased circulation and reduced pain.

It is the only diode-based therapy (conducts electric current in only one direction and restricts current from the opposite direction) that has numerous studies published in the medical journals

How to use Anodyne machine?

• Place the pads directly over theproblem area.

• Hold the therapy pads in place with attachment system and treat hands-free for 30 minutes per day.

• Monochromatic infrared energy, the photoenergy-emitting pads, attached to a power unit, are placed on the limbs of a patient with neuropathy.

Electromagnetic Therapy

• A therapeutic technique that consists of applying artificial magnetic fields on an affected part of the human body with controlled intensity and frequency.

• So, we expose the affected body’s area to a magnetic field like the Earth’s field (intensity of 0,5 Gauss),but with possible higher levels of frequency and different application times.

• Electromagnetic fields (EMFs) provide a non-invasive, safe, and easy method to treat site of injury, pain and inflammation .

• The most common and disabling musculoskeletal diseases are osteoarthritis, back and neck pain, tendinopathy, fibromyalgia and myofascial pain.

• Magnetic field therapy promotes bone healing, treat osteoarthritis and inflammatory diseases of the musculoskeletal system, alleviate pain, enhance healing of ulcers and reduce spasticity.

• Eextremely low frequency (ELF) magnetic fields in the pico tesla and milli tesla ranges are aimed at improving neurotransmission and correcting local immune pathology.

(PEMFs) Pulsed electromagnetic fields

Important modality in magnetotherapy and recent technological innovations, offers excellent computer-controlled system known as low field magnetic stimulation (LFMS).

Biological Effects include:

- Enrich the oxygen in the cell & Improve its utilization.

- Increasing the metabolism

- Enhance ATP and energy production on the cellular level.

• An analgesic and anti-nociceptive efficacy, like the opioid analgesic effect of pulsed electromagnetic field (PEMF) is reported by scientist literature but the clear biological and biochemical mechanism on pain remains unknown.

• Some studies have shown that short-term exposure to electromagnetic fields influences inflammatory cellular and neurological processes, such as activation and inhibition of various neurotransmitters.

Types of artificial magnets used:

1. Not Stationary (Electro-magnets): work only when connected to electricity as pulsed: (Pulsed generator connected to a coil & magnetic field current flow in tissue).

2. Stationary (Permanent magnets): are fully charged with electric current and remain permanently magnetized.(Earings, bracelets, necklace)

- Unipolar: discrete magnets arranged with same pole facing patient’s skin

- Bipolar: both North & South poles facing patient’s skin.

Application Norms

The patient must NOT wear metal objects as they can distort the magnetic field.

It is better for the affected zone of the patient to be in direct contact

with solenoid.

The treatment response is quickly, but it also depends on pathology, age, and

other conditions.

After 10 sessions of no improvement , better to stop the therapy.

The therapy time 30 minutes to 2 hours maximum.

Sessions must be applied continuously; even two sessions at the same day but with 12 hours between

them.

Electromagnetic fields therapy can be complemented with other therapies

Contraindications

• Existence of acute infection, especially septicemia and tuberculosis (dissemination can occur)

• Hemorrhagic focus (bleeding ulcers, intestinal hemorrhages) as vasodilatation effect can worsen the case

• Cardiac pacemaker, because it can produce a malfunction.

• Pregnancy, ??foetal damages

• Tumor existence as they can be disseminating