Electrotherapy Simplified Basanta Kumar Nanda
Page numbers followed by f refer to figure and t refer to table.
Absolute reaction of degeneration (ARD) 198
Absorption 91, 371
Acne vulgaris 453
Acoustic streaming 381
Allergic rhinitis 161
Alpine sun lamp 442f
Ammeter 73
Ampere's theorem 35
Amplitude modulated current 241f
Amplitude modulated frequency 243
Amplitude modulated TENS 178f
Anesthetic skin 153, 186
chronic indurated edema of 413
sprain lateral ligaments of 388
Antibiotics, application of 159
preparation of 4, 133, 150, 161, 264, 269, 329, 433, 360462
testing of 4
Application of anti-inflammatory drugs, application of 159
Arndt-Schultz law 344f, 423
Arterial insufficiency 273
Articular cartilage, repair of 390
Artificial magnets 32, 32f
types of 32
Asymmetrical biphasic TENS pulses 110f
Atom 12
structure of 12f
Atomic mass 13
Autoimmune disease 6
Automatic timer 395
Autonomic nervous system 249
Autotransformer 48, 49f
Bacterial infection 309
Basal ganglia 103
Beam nonuniformity ratio 378
Bell's palsy 133
Biot Savart's law 35
Blood flow 259
Blood pressure 307
Bone 467
healing 347
Brainstem structure 170
Breast implants 404
Burn 163, 253, 268, 334, 363, 402, 416, 456
Burst TENS 180f
Cable electrode 300
Cable method 325
Calibration 395
Cancer 451
Capacitance 17
Capacitor 18, 19f, 314
charging and discharging of 22
construction of 19
electrical field of 22
types of 19
uses of 24
Carcinogenesis 456
Cardiac disease 152, 290
Cardiac failure 364
Cardiac, kidney and liver disease 455
Cardiovascular disease 467
Carotid sinus 186
Carpal tunnel syndrome 390, 430
Cartridge 80f
Cathode ray
oscilloscope 216
tube 219f
Cauda equina compression 467
Cell metabolism 248
Central intervertebral disc herniation 467
Central nervous system 403
Cerebellar contribution 102
Cerebral cortex 171
Cervical spine traction 467
Cervical traction 467, 470f
Charging current 23f
Chest 253
Choke coil 48, 50f
uses of 50
Chronaxie 206
Circuit 120
working of 120
Circulation, control of 248
CNS, electrophysiology of 102
Cold compression units 287
Cold pack 285
Cold urticaria 289
Collagen tissues 260
Collimation 421
Combination therapy 251, 252f
Complete denervation 201
Compressive syndrome 390
Condenser field method 314
Conductor 17
length of 27
material of 27
Constant current stimulation 202f
Constant direct current 111
Constant voltage stimulation 202f
Continuous mode 376
Continuous traction 465
Contraplanar method 322
Contrast bath 271, 273
Conventional porcelain fuse 80f
Conventional TENS 178f
Coplanar method 320
Cord sign 467
Correct electrode spacing 320f
Cross fire method 323
Cryoglobulinemia 289
Cryotherapy 277
application of 285
Current electricity 15
Current intensity 246
measurement of 66
Cutaneous vasodilatation 411
Damped oscillations 24f, 294f
Deep vein thrombosis 253
Defective arterial circulation 364
Defective skin sensation 268, 290
complete reaction of 198
detection of reaction of 213t
partial reaction of 198
Delayed Colle's fracture union 390
Denervated muscles, stimulation of 124, 148
Dermal ulcer 388, 413
Descending pain suppression 174, 175f, 248
Diabetes mellitus 273
Dielectric constant 18
Diminished thermal sensation 364
Diode lasers 426
Diode valve 52, 53f
functions of 53
symbol of 53f
Dipoles, rotation of 303, 304f
Direct contact method 398
Direct current 25, 107
Direct irradiation over pregnant uterus 431
Disc electrodes 300
Discharging current 24f
Discitis 467
Dissociation 157
Dorsal horn 169
Dosage of SWD, classification of 333t
Earth free circuit 48f
Earth shock 83
Eczema 453
Eddy current 44, 44f
Edema 204, 206, 207
control of 282, 346
reduction 189
relief 160, 249, 413, 430
Electric current, nature of 25
Electric field, concentration of 334
Electric shock 78, 82, 84, 163, 416, 432
causes of 83
prevention of 86
treatment of 85
types of 82
Electrical energy 14
Electrical excitability 96
Electrical fundamentals 11
Electrical measurement systems 66, 68
Electrical neuromuscular stimulator, testing of 136f
Electrical safety 78
Electricity, distribution of 66
Electrode 300
correct size of 315f
positioning, methods of 320
size of 315
spacing 317
Electrolytic capacitor 21, 21f
Electromagnetic induction, Faraday's law of 42
Electromagnetic spectrum 2f
Electromagnetic wave 295
Electromotive force 16
Electromyography 214, 232
recording system 216f
Electron 13
Electrotherapy, application of 3
EMG biofeedback, techniques of application of 234
Endocrine glands 431
Epidermis, thickening of 450
Epilepsy 187
Epiphyseal plate 404
Evoked muscle action potential 209f
Excess current 336
Eyes, radiation of 455
Facial muscles, stimulation of 145
Facial nerve in face, course of 146f
Faraday's experiments 40
Faradic current 108
Faradic foot bath 144, 145f
Faradic interrupted direct current (IDC) test 213
Faradic type currents 119, 123
production of 119
type currents, techniques of application of 133
Faradism under pressure 131, 132f
Fatigue 207
Faulty electrical components 84
Faulty switch and fuse connection 84
Fever 340, 455
Fixed capacity capacitor 19
Fleming's right hand rule 42
Fluidotherapy 273, 274
Fluorescent lamps 444
Fluorescent tubes 441
Foreign bodies 6
Fracture 6, 404
healing 185, 390
Frequency sweep 243
Functional electrical stimulation 133, 192
Fungal infection 160
F-wave 212, 212f
Galvanic current 111
Galvanic tetanus ratio 213
Galvanic type currents 148
techniques of application of 150
Galvanometer 68
Gangrene 364
Gate control theory 173, 174f
Goeckerman regimen 452
Grid leak resistance 300
Grid system 74
Growing epiphysis 340
Half value distance 372
Half wave rectification 60, 60f, 61f
Half wave rectified sinusoidal current 113, 190
Headache 417
application of 171
loss 314
production 294
therapy 258
types of 263
Heliotherapy 463
Hemorrhage 152, 252, 339, 364, 431
Herpes zoster 390, 391
Heterogeneous matter 12
High frequency choke coil 50
High frequency currents 106, 116, 291
properties of 293
transmission of 302
High voltage pulse galvanic stimulation 110, 187
Hip joint 329f
Homogeneous matter 11
Hot pack, application of 269
H-reflex 211, 212f
Humidity 204
HVPC, twin pulses of 111f
Hydrocollator packs 268
Hyperemia 156
Hypermobility 467
Hypertension 454, 467
Hypoesthetic skin 153
Hysterical paralysis 128
Ice massage 287
Ice towels 287
IDC, application of 150
Idiopathic hyperhidrosis, relief of 157
Impaired blood flow 336
Impaired thermal sensation 338
Implanted cardiac pacemakers 364
Improper earth connection 84
Induction theory 8
Inflammation 6, 206
acute 282, 404
aggravation of 268
causes of 6
chronic 267, 273
irradiation, dangers of 416
lasers 426
production of 408
radiation 407, 408, 411
dosage of 413
Insulators, molecular distortion of 304f
Intensity 392, 420
Interferential current 114, 240
physical principles of 242
Interferential therapy 252
machine 250f
Interferential treatment, dangers of 253
Intermittent traction 465, 466
Interrupted direct current 111
Intrauterine contraceptive devices 341
Ionic polarity 155
Ions 13
motion of 304f
penetration 156
vibration of 303
Iontophoresis 153, 405f
dangers of 163
dosage of 162
mechanism of 154
physics of 155
principles of application of 161
Ischemia 204, 206, 207
Ischemic tissues 339
Ischemic ulcers 160
Joint cement 403
Joint stiffness 412
Joule's law of heating 29
Knee joint, edema in 430
Kromayer lamp 443, 443f, 462
Lamp, positioning of 415
Laplace's law 35
classification of 424
physics of 420
production of 421
types of 425
Laws governing radiation 87
Leakage currents 84
Lenz's law 42
Lewis hunting response 279f
Limbic system 103
Local circulation 191
Long duration pulses 111
Long wave diathermy 350
application of 352f
machine 351f
Low back pain 184, 412
Low frequency
choke coil 48
currents 106, 117
Low intensity laser 428
principles of application of 432
therapy 418
Low level amperage 155
Lower limb, motor points on back of 141f
Lumbar spine
dysfunction of 413
traction 469
Lumbar traction 467, 472t
Lumbricals, stimulation of 145f
Macroshock 82
properties of 33
types of 32
Magnetic and electrostatic disturbance 295
Magnetic energy 31
Magnetic induction 34
Magnetic lines of force 33, 34f
Magnetic poles 33
Magnetron valve 353f
Main electricity supply system 75f
Malignant tumors 339
Maxwell's corkscrew rule 38, 38f
Mean power, derivation of 343
Medium frequency currents 106, 114, 239
Medium pressure mercury arc lamp 441
Mercury vapor lamp 440, 441
Metal rectifier 59, 59f
symbol of 59f
Mica capacitor 20, 20f
Micro massage 383
Microshock 82
Microwave diathermy 352, 358, 359
dosage of 359
production of 353
Microwave radiations, laws of 355
Mild shock 83
Modern electrical stimulator 109f
Modified direct current 146
Moist heat packs 268
Molecular distortion 303
Monophasic TENS current 110f
Monoplanar method 324
Motor conduction velocity 209
Motor nerves, stimulation of 124
Motor neuron pool activity 126f
Motor point 138f
stimulation of 137
Moving coil galvanometer 68
Multiple sclerosis 283
Multisynaptic ascending system 169
Multivibrator circuit 119, 119f
action, re-education of 127
contraction 124
facilitation of 125, 281, 283
depolarization 101
neuromuscular transmission and activation of 99
stimulation of 197
location of 204
performance 262
re-education and strengthening 191
relaxation, induction of 310
spasm, reduction of 189, 412
stimulation 189, 247
strength, alteration of 280
tissue 307
tone 261
Musculoskeletal disorders 429
Musculoskeletal injuries 236
application of 363
principles of application of 361
Myoelectric signal 217
Myofascial pain 430
Myofascial trigger points 430
accommodation 100
action potential 99f
and muscle, electrophysiology of 96
tests 208
velocity 209, 280
conductivity 208
depolarization and repolarization of 97f
electrical stimulation of 100, 101f
stimulation of 196
types of 95
healing 347
injury 128
root lesion 208
transmission 96
and muscle contraction, electrophysiology of 92
Neurogenic pain 160
Neuromuscular electrical stimulator and accessories 135f
Neuron 94, 95f
Neutron 13
Noninsulated floorings 84
Nonluminous infrared lamp, parabolic reflector of 410f
Non-steroidal anti-inflammatory drug 160
NPN transistor 57f
N-type semiconductor 55, 56f
Ohm's law 25, 26, 26f
limitations of 26
Oscillator 300
circuit 24f, 298
Osteoarthritis 429
Osteomyelitis 467
Pacemaker 253, 403
Pad electrodes 300
Pain 164, 206, 267, 430
acute 165
arthritic 184
chronic 9, 165, 166
control 235, 282, 388
gate theory 247
modulation 172f, 173, 188
levels of 171
role of electrical stimulation in 175
musculoskeletal 184
neurophysiology of 164
obstetric 185
pathway 166
general outline of 166f
relief 191, 249, 261, 359, 412
Painful arc syndrome 388
Paper capacitor 20, 20f
Parabolic reflector 89f
Paraffin wax bath 263
Peripheral vascular disease 273, 289
Permanent magnet 32
Phonophoresis 153, 404406
Pigmentation 410
Plantar warts 390, 391
Positive sharp waves 224, 224f
Potentiometer 68, 69
application of 70
Power plug 78
Pregnancy 152, 253, 186, 338, 403, 467
Premature skin aging 456
Pressure ulcers 389, 413, 429
Proton 12
Pruritus 454
Psoriasis 413, 452
Psoriatic arthritis 413
PSWD, dosage of 349
P-type semiconductor 55, 56f
Pulmonary tuberculosis 455
Pulse ratio 208
Pulsed mode 376
Pulsed short wave
application of 349
diathermy 341, 345
parameters of 342
production of 341
closer separation of 111f
wider separation of 111f
PUVA 452
apparatus 445
treatment 461
Quadriceps, group stimulation of 143f
Quadripolar application of IFT 244f
Radiation, wavelength of 410
Raynaud's disease 430, 431
Rectifiers 58
Reflection 88, 374
Refraction 90, 375
Refractory period 100, 197
Repetitive discharge 226f
Resistance, combination of 28
Resonator circuit 300
Resonator coil 300
Reticular formation 170
Rheumatoid arthritis 6, 133, 429, 467
Right hand thumb rule 38, 39f
Ruby laser 425
production of 425f
Russian current 115, 115f, 254, 254f
for quadriceps strengthening, application of 255f
Sacroiliac joint dysfunction 388
Scar mobilization 160
S-D curve plotting, method of 200
Semiconductor diode 56
construction of 57
Sensory motor cortical contribution 102
Sensory nerves, stimulation of 124
Severe osteoporosis 467
Shock, severity of 83
Short duration currents 108
Short wave diathermy 296, 298
apparatus 299f
production of 298
adhesive capsulitis of 388
calcific tendinitis of 389
joint, treatment of 322f
Sinusoidal current 112, 112f, 189
allergy 268
cancer 455
hypersensitivity 290
infection 253, 268
irritation 163
lesion 413
resistance 206
sensation for thermal
sensitivity, testing of 331f
structure of 410
temperature 203
texture of 207
Smoothing circuit 64f
Snow rule 38
Soft tissue
extensibility of 348
injury, acute 346
trauma 6
Spasm reduction 256
Spasticity 235
decrease of 281
reduction 132, 283
Spatial average intensity 377379
Spatial peak intensity 377
Spherical emitter 355f
Spinal cord injury 235
Spinal cord tumor 467
Spinal tract 169
Spontaneous emission 421f
Stable cavitation 381
Static electricity 14
Static transformer 44, 45f
functions of 45
working of 45
Step-down transformer 46, 46f, 298
Step-up transformer 45, 46f, 299
Stiff joints 267
Stimulating electrode, positioning of 207
Strength duration curves 199
Strengthening weak muscles 129
Stress incontinence 250
Stroke 235
Subcutaneous fat 206
Superficial fat 204
Surgical skin incision 389
application of 314
dosage of 332
machine, components of 298
techniques of application of 329
Sweat glands 307
Swelling, post-traumatic 273
Symmetrical biphasic TENS pulses 110f
Systemic lupus erythematosus 455
Tarsal tunnel syndrome 390
Tear medial meniscus 390
modes 177
parameters of 176
techniques of application of 181
uses of 184
Tension theory 8
Thalamus 170
Therapeutic currents 104
Thrombophlebitis 403
differential heating of 312
fluids, viscosity of 259
healing 262
facilitation of 191
Traction, types of 465
Traditional UV lamp 443f
Training new muscle action 127
Transcutaneous electrical nerve stimulation 109, 171
Transcutaneous neural stimulators 338
Transformer 44, 298
types of 44
Transistor, uses of 58
Triode valve 53, 54f, 299
symbol of 54f
uses of 54
Trophic stimulation 132
Two-pin connections 84
application of 376
dosimetry of 391
for tennis elbow, application of 386f
intensity of 377
machine, choice of 394
over bone, reflection of 375f
principles of application of 394
production of 367
therapy unit, testing of 398f
therapy, dangers of 402
transducer over tissue, movement of 400f
Ultraviolet dosage, progression of 459
Ultraviolet radiation 438, 446, 451
classification of 439
dangers of 456
dosimetry of 457
principles of application of 460
production of 440
Unstable cavitation 381
Unstable fracture 467
Upper limb, motor points on back of 140f
UVR, measurement of 446
Vapocoolant sprays 288
Varicose ulcers 389
Vasospastic disorders 289
Velocity 88
Venous and arterial thrombosis and thrombophlebitis 152
Venous thrombosis 340
Vertebral artery disease 467
Vitamin D
deficiency, treatment of 454
production of 450
Vitiligo 454
Voltage halving circuit 61
Voltmeter 68, 71, 72
Water bag method 401
Water bath application 400
Water cooled medium pressure mercury vapor lamp 443
Wavelength 87
Wax bath, purification of 266
Wax treatment, application of 264
Wheatstone bridge 68, 69f
Whirlpool bath 274, 275f, 276, 277
uses of 276
Wound healing 188, 347, 388, 428
Chapter Notes

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Introduction, Inflammation, Repair, and Role of Physical AgentsCHAPTER 1

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 = 109m
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.
zoom view
Fig. 1.1: Electromagnetic spectrum
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.
The following should be considered before applying any electrotherapeutic modality to a patient:4
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.
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.
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.
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
While the treatment is applied, the patient must be observed throughout to ensure that, the treatment is progressing satisfactorily and is without adverse effects.
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.
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.
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
  • Autoimmune disease (rheumatoid arthritis)7
  • 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.
  1. 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.
  2. 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.