Physiotherapy as a branch of medical science has a very old history, though tremendous technological developments have taken place in the recent past. Hippocrates (430–380 BC) has mentioned the use of traction, manipulation, etc. as is evident from ancient medical records. There were greater stresses in the development of physiotherapy following World War II, which included the use of electrotherapy. Though the concept of electricity as a therapeutic agent is not a recent innovation, the use of electricity 2for therapeutic purposes has grown in recent years. As early as 1757, Dr Benjamin Franklin has mentioned the administration of “electric shocks” to his neighbor Mr John Pringle for Frozen shoulder with good results.
Electrotherapy is the treatment of patients using electrical modalities that apply electric current directly to the body, such as low, medium and high frequency currents, and modalities, such as ultrasound, hydrocollator (moist hot pack unit), cryotherapy unit, etc. where electricity is indirectly used to apply ultrasound, heat, cold, etc. to the body to get therapeutic benefit. Electrical forces are applied to the body to bring about physiological changes at the tissue level by altering the cell metabolism through vascular and neural factors as well as by the direct effect of electricity on the tissues that help in producing therapeutic benefits.
Actinotherapy in its simplest form is “the use of visible light and invisible radiations for the treatment of patients”. The word “actis” is a Greek word, which means “a ray”, and the treatment by rays (using lamp as a source of light) is called Actinotherapy. May it be the application of electric currents directly (e.g. low frequency, medium frequency currents and high frequency currents) to the body or the application of LASER, infrared, ultraviolet, etc. where electric current is not applied directly but is used to produce these energies, the ultimate event is the production of therapeutic effects within the body. Although not electrical in nature, ultrasound is included in electrotherapeutic modalities, as it is produced using high frequency currents. As physiotherapists we use many of the natural phenomena, such as light, heat, cold, sound and mechanics in our daily practices adapting them to our specific medical needs.
The electromagnetic spectrum ranging from cosmic and gamma radiations to radio and TV transmission (Fig. 1.1) is the source of most of electrotherapeutic modalities.
1 pm = 10–12m 1 nm = 10–9m
Many diagnostic procedures are now done electronically, such as electrocardiogram (ECG), electroencephalogram (EEG), electromyogram (EMG), as well as nerve conduction velocity (NCV) studies, strength-duration curve (S-D curve) testing, etc.
3Before application of treatment it is essential that the student/ clinician ensures that his knowledge on anatomy and physiology is sufficient to localize the site of lesion, such as the depth at which the damaged tissue is located, the possible pathophysiology giving rise the signs and symptoms, etc. The modality selected is based on the physical and physiological effects of those modalities on tissues, and the evidence available on the efficacy of such modalities on similar type of lesions.
The student/clinician needs full information on the followings before he/she applies treatment to the patients:
- What is the exact need of the subject?
- What is the diagnosis of the disease/disorder?
- What are the underlying pathology present and the stages of the disease/disorder (acute/subacute/chronic)
- What are the presenting signs and symptoms?
- Which modality is best to solve the problems of the patient (based on the clinical evidence)?
- What are the contraindications and possible dangers?
- What safety precautions need to be taken while applying such modalities?
The course of the disease and the repair processes involved could be as follows.
Acute: A condition is said to be acute if the signs and symptoms are very severe. Such conditions are usually recent in onset. This stage never lasts for more than two weeks.
Subacute: A condition is said to be subacute, if the signs and symptoms are less severe than what was present in the previous stage. This stage usually lasts for more than four weeks.
Chronic: A condition is said to be chronic, if the signs and symptoms are less severe than what was present in the subacute stage, but it persists for long periods. This stage lasts for months and years.
BASIC GUIDELINES FOR THE APPLICATION OF ELECTROTHERAPY
Whether the intended effect can be achieved by this treatment? It should be remembered that in certain situations the effect of the treatment is achieved immediately, e.g. pain relief after application of heat, ice, TENS, etc. whereas in other cases the effectiveness come after a long period of application of the modality.
Safety factors associated with the particular treatment must be considered. The therapist should be able to take a clinical decision on the selection of the modality with supportive evidence behind, so that no undesirable effect is produced and the best desired result is achieved. As each modality has its potential dangers and contraindications, no treatment should be given without appropriate knowledge of these factors, and adequate precautions should be exercised to keep the dangers away.
Whether the method of treatment selected is the best, based on appropriate clinical reasoning, economical in terms of patient/therapist time or other costs?
After considering the above facts, the therapist should apply the particular electrotherapeutic modality in a competent way.
Periodic examinations and assessments should be done for the selection and application of these modalities. Some of the basic guidelines, which can provide the framework for sound clinical practice are given below.
PREPARATION OF APPARATUS
This consists of assembling of the apparatus, testing, setting up.
Assembling of the Apparatus
All the apparatus and equipments needed should be assembled and suitably positioned. Visual checks should be made of electrodes, leads, cable, plugs, power outlets, switches, controls, dials and indicator lights.
Testing of Apparatus
This includes the setting of apparatus and any necessary testing of it prior to application. Treatment should be made only when these have been made satisfactorily. When the physiotherapist tests the apparatus on his own body, as needed in some, like SWD, low frequency currents, etc. it should be done in front of patients to alleviate fear from them.5
Setting up
The apparatus is setup to ensure optimum therapeutic effect and safety.
PREPARATION OF THE PATIENT
This has the major components like informed consent, explanation, examination and testing, and positioning.
Informed Consent
Before any treatment is applied, the duty of the therapist is to achieve informed consent of the patient, preferably in writing, to undergo the particular treatment, after explaining him about the potential benefits and risks associated.
Explanation
It is essential that the physiotherapist explains the patient about the nature of the treatment he is applying and the type of sensation the patient will experience, and the need to report in the event he/she gets an abnormal response. The detail “do's” and “don'ts” of a particular treatment should be thoroughly explained, as for example—to remain still and not to touch the cables, wall pipes, etc. while taking SWD treatment.
Examination and Testing
Before any treatment is applied and after the patient is made aware about the treatment methods, the therapist must do specific examinations of the patient as a whole (the patient's past medical records if available should also be checked), and the part to be treated, to find out any contraindications for the treatment. This includes testing the sensitivity of the skin over the treatment area for pain, as well as thermal sensation. Patient's receiving radiotherapy require special consideration (Brooks 1998). All forms of electrotherapy to the irradiated skin are considered contraindicated for a period of months (period of six months in most of the modalities) after the irradiation.6
TREATMENT APPLICATIONS
While the treatment is applied, the patient must be observed throughout to ensure that, the treatment is progressing satisfactorily and is without adverse effects.
TERMINATION OF TREATMENT
At the termination of treatment the part treated should be re-examined to ensure that the desired effects have occurred, if visible, e.g. superficial vasodilatation (mild erythema) and there are no unwanted effects. If any unwanted effects, such as blister, burn, scald, etc. have occurred, necessary steps must be taken for their remediation.
DOCUMENTATION
An accurate record of all the parameters of treatment, including region treated, technique, dosage, and the resultant effect must be made. This is both for the assessment purposes, follow-up services, and for legal requirements.
INFLAMMATION, REPAIR AND ROLE OF THE PHYSICAL AGENTS
Inflammation
The word is derived from inflamer (latin word) meaning “to set on fire”. It begins when the normal physiology of tissue is altered by disease and trauma. Cornelius Celsus first described the inflammatory process which is characterized by four cardinal signs, such as: (i) calor (heat), (ii) rubor (redness), (iii) tumor (swelling), (iv) dolor (pain). Later on Functio laesa was added to this list by Virchow, making the number of cardinal signs of inflammation 5 (five).
Common Causes of Inflammation
This include:
- Soft tissue trauma (sprain, strain, contusions)
- Fractures
- Foreign bodies
- Microbial agents (bacteria)
- Chemical agents (acid, alkali)
- Thermal agents (burns, frost bite)
- Irradiation (UVR, IR).
The physiotherapist treats a variety of inflammatory conditions resulting from trauma (direct/cumulative), surgery, sports injuries, etc. The clinician who treats, such injuries needs to understand the physiology of inflammation and repair, and how it can be modified to facilitate early healing. It must be understood that the physiotherapist can enhance healing by appropriate application of physical agents, exercises and manipulations, etc. The success of patient management requires the understanding of the biomechanics, the phases of tissue healing and effects of immobilization and therapeutic interventions on the healing process.
The process of inflammation and repair consists of three phases: inflammation, proliferation, and maturation.
Phase of Inflammation
This phase prepares the wound for healing, and lasts for 1–6 days. This is the immediate protective response which attempts to destroy, dilute, or isolate the cells or agents that may be at fault. It is a normal and prerequisite to healing and healing fails to occur if there is no inflammation. Though beneficial for the healing process it is harmful for the patient in terms of the pain and loss of function warranting its early resolution (acute tennis elbow). The physiotherapist is called upon to treat the inflammatory disorders, so that the patient gets relief from the pain and spasm and gets the functional restoration.
Phase of Proliferation
This is the second phase of tissue healing and lasts from 3rd day up to 20 days. Its purpose is to cover the wound and impart strength to the injury site. The four processes occurring simultaneously in this phase are epithelialization, collagen production, wound contraction, and neovascularization. In this phase careful application of certain electrophysical modalities, accelerate the healing process causing early functional restoration (e.g. application of ultrasound to the common extensor origin to cause healing, in case of a tennis elbow).8
Maturation Phase
This phase which is a transition from the phase of proliferation, produces changes in the size, form and strength of scar tissue. It is the longest phase in the healing process and can persist over a year after the initial insult. The ultimate goal of this phase is restoration of the prior function of the injured tissue (e.g. ultrasound is applied to mobilize the scar formed at the common extensor origin, in case of persisting pain in tennis elbow). As in this phase of tissue healing a scar is formed, and as the scars are inelastic, and the collagen fibers that form the scar are largely responsible for the final function of the injured area, treatment of the healing scar is very very essential to normalize the alignment of the collagen fibers, so that mobility is restored in the injured area causing functional restoration.
The two theories which are said to operate in aligning the collagen fibers include: (i) Induction theory and (ii) Tension theory.
- Induction theory: This states that, it is the property of the body to form a scar that mimics the characteristics of the tissue it is healing. Thus a dense tissue induces a dense highly cross linked scar, where as a more pliable tissue results in a loose, less cross linked scar. In case of a more cross linked scar is getting formed, physical agents (such as ultrasound, electrical stimulation, heat, exercise, etc.) need to be applied to minimize the cross linking as more the cross linking, more is the functional limitation.
- Tension theory: As per this theory, the internal and external stresses places on the injured area during the maturation phase, determines the final tissue structure. Muscle contraction, joint movements, temperature changes soft tissue loading, etc. are thought to affect collagen structures, there by minimizing cross linking, causing proper alignment of the collagen fibers in the direction of the original tissue, there by facilitating functional restoration. In soft tissue injury where there are abundant type I, III, VII collagen fibers, in the phase of maturation where these collagen fibers need to be prevented from cross linking and tightness, heat is applied in a controlled manner, as it enhances the extensibility of such collagen fibers, there by following the application of heat, if exercises are given mobility in the injured joint is achieved.9
Pain which is an experience based on a complex interaction of physical and psychological processes is defined as “an unpleasant sensory and emotional experience associated with actual or potential tissue damage”. This is the most common symptom prompting patients for medical help. It can be typed according to its duration or source as acute, chronic or referred.
Acute Pain
Acute pain is defined as “pain which is of less than six months in duration and has an underlying pathology which can be identified”. This is felt in response to an actual tissue damage and resolves once the damaged tissue heals. The goal of management of acute pain is to apply modalities that can resolve the underlying pathology, that is the source of pain.
Chronic Pain
Chronic pain is defined as “pain that does not resolve in the usual time it takes for the disorder to heal and persists for a duration greater than six months”.
Referred Pain
This is the pain which is felt in one area, when the actual tissue damage is in another area. It is the feeling of pain at a location distant from its source. For example—a lumbar radiculopathy at L5–S1 level causes feeling of pain at the lateral leg, a pathology in hip causes pain over the knee, a pathology in the shoulder causes referred pain on the elbow, etc. Sometimes the pain is referred from the internal organs, such as involvement of the heart causes a referred pain over the left shoulder. In such situations, the clinician should be thorough in deciding the source of pain, as in referred pain conditions the source of pain need to be manipulated/altered either by the application of physical agents, manipulation, exercises, etc.
Role of Physical Agents
The physical agents, such as heat, cold, exercises, massage, etc. should be directed to the injured tissues that causes a functional limitation, to minimize the inflammation (cold), accelerate healing (ultrasound, laser, heat, etc.), realign the collagen fibers that make the scar (ultrasound, PWB, SWD, MWD, etc.), reduce pain (heat, cold, TENS, IFT, etc.). One important thing to be considered by 10the therapist is whether, the modality selected has the physical properties (such as—can it penetrate to reach the target tissue?), physiological properties (such as—can it slow down repair, e.g. cold, accelerate healing, e.g. heat, enhance nerve conduction, e.g. heat, electrical stimulus), and the evidence on the efficacy of the modality in question. The possible hazards (such as eye damage by laser, burn by heat, etc.) should be given due importance in electrical treatments.