Part 2 book “Therapeutic modalities in rehabilitation” has contents: Therapeutic ultrasound, extracorporeal shockwave therapy, shortwave and microwave diathermy, spinal traction, intermittent compression devices, therapeutic massage.
PART FOUR Sound Energy Modalities chapter 10 Therapeutic Ultrasound David O Draper and William E Prentice OBJECTIVES Following completion of this chapter, the student will be able to: Analyze the transmission of acoustic energy in biologic tissues relative to waveforms, frequency, velocity, and attenuation Break down the basic physics involved in the production of a beam of therapeutic ultrasound Compare both the thermal and nonthermal physiologic effects of therapeutic ultrasound Evaluate specific techniques of application of therapeutic ultrasound and how they may be modified to achieve treatment goals Choose the most appropriate and clinically effective uses for therapeutic ultrasound Explain the technique and clinical application of phonophoresis Identify the contraindications and precautions that should be observed with therapeutic ultrasound In the medical community, ultrasound is a modality that is used for a number of different purposes including diagnosis, destruction of tissue, and as a therapeutic agent Diagnostic ultrasound has been used for more than 50 years for the purpose of imaging internal structures Historically, diagnostic ultrasound has been used to image the fetus during pregnancy More recently, with a reduction of equipment costs, significant improvements in image resolution, real-time ultrasonographic imaging and detailed anatomic imaging, diagnostic ultrasound has expanded to various clinical practices that evaluate, diagnose, and treat musculoskeletal disorders Diagnostic musculoskeletal ultrasound (MSK) can identify pathology in muscle, tendons, ligaments, bones, and joints.1 Ultrasound has also been used to produce extreme tissue hyperthermia that has been demonstrated to have tumoricidal effects in cancer patients In clinical practice, ultrasound is one of the most widely used therapeutic modalities in addition to superficial heat and cold and electrical stimulating currents.2 It has been used for therapeutic purposes as a valuable tool in the rehabilitation of many different injuries primarily for the purpose of stimulating the repair of soft-tissue injuries and for relief of pain,3 although some studies have questioned its efficiency as a treatment modality.4 As discussed in Chapter 1, ultrasound is a form of acoustic rather than electromagnetic energy Ultrasound is defined as inaudible acoustic vibrations of high frequency that may produce either thermal or nonthermal physiologic effects.5 The use of ultrasound as a therapeutic agent may be extremely effective if the clinician has an adequate understanding of its effects on biologic tissues and of the physical mechanisms by which these effects are produced.3 ULTRASOUND AS A HEATING MODALITY Chapter 9 discusses heat as a treatment modality Warm whirlpools, paraffin baths, and hot packs, to name a few, all produce therapeutic heat However, the depth of penetration of these modalities is superficial and at best only 1–2 cm.6 Ultrasound, along with diathermy, has traditionally been classified as a “deep heating modality” and has been used primarily for the purpose of elevating tissue temperatures Ultrasound • is one of the most widely used modalities in health care • Ultrasound and diathermy = deep heating modalities Suppose a patient is lacking dorsiflexion It is determined through evaluation that a tight soleus is the problem, and as a clinician your desire is to use thermotherapy followed by stretching Will superficial heat adequately prepare this muscle to be stretched? Since the soleus lies deep under the gastrocnemius muscle, it is beyond the reach of superficial heat One of the advantages of using ultrasound over other heating modalities is that it can provide deep heating.7,156 The heating effects of silicate gel hot packs and warm whirlpools have been compared with ultrasound At an intramuscular depth of 3 cm, a 10-minute hot pack treatment yields an increase of 0.8°C, whereas at this same depth, 1 MHz ultrasound raises muscle temperature nearly 4°C in 10 minutes.8,9 At 1 cm below the fat surface, a 4-minute warm whirlpool (40.6°C) raises the temperature 1.1°C; however, at this same depth, 3MHz ultrasound raises the temperature 4°C in 4 minutes.8,10,11 TRANSMISSION OF ACOUSTIC ENERGY IN BIOLOGIC TISSUES Unlike electromagnetic energy, which travels most effectively through a vacuum, acoustic energy relies on molecular collision for transmission Molecules in a conducting medium will cause vibration and minimal displacement of other surrounding molecules when set into vibration, so that eventually this “wave” of vibration has propagated through the entire medium Sound waves travel in a manner similar to waves created by a stone thrown into a pool of water Ultrasound is a mechanical wave in which energy is transmitted by the vibrations of the molecules of the biologic medium through which the wave is traveling.12 Transverse Versus Longitudinal Waves Two types of waves can travel through a solid medium, longitudinal and transverse waves In a longitudinal wave, the molecular displacement is along the direction in which the wave travels Within this longitudinal wave pathway are regions of high-molecular density referred to as compressions (in which the molecules are squeezed together) and regions of lower molecular density called rarefactions (in which the molecules spread out) (Figure 10–1) This is much like the squeezing and spreading action when using a child’s “slinky” toy In a transverse wave, the molecules are displaced in a direction perpendicular to the direction in which the wave is moving Although longitudinal waves travel both in solids and liquids, transverse waves can travel only in solids Because soft tissues are more like liquids, ultrasound travels primarily as a longitudinal wave; however, when it contacts bone a transverse wave results.12 Frequency of Wave Transmission The frequency of audible sound ranges between 16 and 20 KHz (kilohertz = 1000 cycles/s) Ultrasound has a frequency above 20 kHz The frequency range for therapeutic ultrasound is between 0.75 and 3 MHz (megahertz = 1,000,000 cycles/s) The higher the frequency of the sound waves emitted from a sound source, the less the sound will diverge and thus a more focused beam of sound will be produced In biologic tissues, the lower the frequency of the sound waves, the greater the depth of penetration Higher frequency sound waves are absorbed in the more superficial tissues Figure 10–1 Ultrasound travels through soft tissue as a longitudinal wave alternating regions of high molecular density (compressions) and areas of low molecular density (rarefactions) Transverse waves are found primarily in bone Velocity The velocity at which this vibration or sound wave is propagated through the conducting medium is directly related to the density Denser and more rigid materials will have a higher velocity of transmission At a frequency of 1 MHz, sound travels through soft tissue at 1540 m/s and through compact bone at 4000 m/s.13 Attenuation As the ultrasound wave is transmitted through the various tissues, there will be attenuation or a decrease in energy intensity This decrease is owing to either absorption of energy by the tissues or dispersion and scattering of the sound wave that results from reflection or refraction.12 Ultrasound penetrates through tissue high in water content and is absorbed in dense tissues high in protein where it will have its greatest heating potential.14 The capability of acoustic energy to penetrate or be transmitted to deeper tissues is determined by the frequency of the ultrasound as well as the characteristics of the tissues through which ultrasound is traveling Penetration and absorption are inversely related Absorption increases as the frequency increases; thus less energy is transmitted to the deeper tissues Tissues that are high in water content have a low rate of absorption, whereas tissues high in protein have a high absorption rate.15 Fat has a relatively low-absorption rate, and muscle absorbs considerably more Peripheral nerve absorbs at a rate twice that of muscle Bone, which is relatively superficial, absorbs more ultrasonic energy than any of the other tissues (Table 10–1) Table 10–1 Relationship Between Penetration and Absorption (1 MHz) When a sound wave encounters a boundary or an interface between different tissues, some of the energy will scatter owing to reflection or refraction The amount of energy reflected, and conversely the amount of energy that will be transmitted to deeper tissues, is determined by the relative magnitude of the acoustic impedances of the two materials on either side of the interface Acoustic impedance may be determined by multiplying the density of the material by the speed at which sound travels inside it If the acoustic impedance of the two materials forming the interface is the same, all of the sound will be transmitted and none will be reflected The larger the difference between the two acoustic impedances, the more energy is reflected and the less that can enter a second medium (Table 10–2).17 • Penetration and absorption are inversely related Sound passing from the transducer to air will be almost completely reflected Ultrasound is transmitted through fat It is both reflected and refracted at the muscular interface At the soft tissue–bone interface virtually all of the sound is reflected As the ultrasound energy is reflected at tissue interfaces with different acoustic impedances, the intensity of the energy is increased as the reflected energy meets new energy being transmitted, creating what is referred to as a standing wave or a “hot spot.” This increased level of energy has the potential to produce tissue damage Moving the sound transducer or using pulsed wave ultrasound can help minimize the development of hot spots.18 Table 10–2 The Percentage of the Incident Energy Reflected at Tissue Interfaces16 Figure 10–2 (a) The anatomy of a typical ultrasound transducer (b) Different diameter ultrasound transducers BASIC PHYSICS OF THERAPEUTIC ULTRASOUND Components of a Therapeutic Ultrasound Generator considerations for use of, 317 hand dipping, 317 high degree of localized heat, 316 physiologic responses, 317 plastic bags, paper towels, 317 protocols, 318 wrapping, 317 Paravertebral muscles (PVMs), 256 PEME (pulsed electromagnetic energy), 442 PEMET (pulsed electromagnetic energy treatment), 442 PEMF (pulsed electromagnetic field), 442 Percussion techniques, 554–556 Peripheral nervous system (PNS), 225 Phonophoresis decreasing levels of perceived pain, 395 enhance delivery of selected medication, 393 hydrocortisone, cortisol, salicylates, 393 and iontophoresis, 175 salicylates enhances analgesic, 393 transmission by media, 394 Pinching technique, 560 Pitting edema, 523 See also Injury edema formation, 526 Pneumatic compression therapy and wound healing, 54 external pressure administration, 54 PNS (peripheral nervous system), 225 Polar Cub, 536 Positional release therapy (PRT), 565 Positive sharp waves (PSWs), 229,258 PresSsion gradient sequential pump, 532 PRT (positional release therapy), 565 PSWD (Pulsed shortwave diathermy), 434 PSWs (positive sharp waves), 229 Pulling technique, 560 Pulsed electromagnetic energy (PEME), 442 Pulsed electromagnetic energy treatment (PEMET), 442 Pulsed electromagnetic field (PEMF), 442 Pulsed shortwave diathermy (PSWD), 434 at consistent intervals, 443 effects, 442 generators, 443 Intellect SWD 100,444 mean power, 443 percentage on time, 443 pulsed electromagnetic energy (PEME), 442 pulsed electromagnetic energy treatment (PEMET), 442 pulsed electromagnetic field (PEMF), 442 PVMs (paravertebral muscles), 256 R Rolfing techniques, 568–570 See also Massage treatment Ruffini corpuscles, 77 Russian currents in electrical stimulation, 141 with polyphasic AC, 142,142f sine wave, 143,144f with and without interburst interval, 142,142f S Sensory receptors See Pain perception, sensory receptors SEPs (somatosensory evoked potentials), 225,266–267 Sequential compression pumps, 531–532,537 See also Intermittent compression treatment techniques Shortwave diathermy case study, 445–446 electrodes capacitance or induction techniques, 436 capacitor, 436–439 inductor, 439–442 equipment autotherm, 436 component parts of, 435 control panels on, 435 dosage guidelines, 436 electrical field and magnetic field, 436 Federal Communications Commission (FCC), 435 output intensity control and indicator, 435 output tuning control, 435 power amplifier, 435 Radarmed 436, 650 radio frequency oscillator, 435 specific absorption rate (SAR), 435 lab activity, 461–462 techniques, 437t treatment time protocols, 444 reflex vasoconstriction, 443 Somatosensory evoked potentials (SEPs), 225,266–267 Sound energy, 4 modalities extracorporeal shock wave therapy (ESWT), 14–15 ultrasound, 14 Spinal traction, 489 articular facet joints effects features, 492 meniscoid structures, 492 osteochondral fragments, 492 synovial fringes, 492 bone effects intermittent traction, 490 Wolff’s law, 490 case study cervical, 513–514 lumbar, 512–513 disk effects annulus fibrosus, 491 fluid-dynamic principles, 491f herniation, 492 nucleus, 491 protrusions and, 491 entire body part, effects, 492–493 indications and contraindications, 514t–515t inversion back-A-traction, 495,495f contraindications, 496 electromyographic activity, 496 spinal column, 495 surgery or musculoskeletal problems, 496 tolerance test position, 496,496f ligaments effects deformation, 490–491 disk material, 491 proprioceptive nerves, 491 slow loading rates, 490 synovial fringes, 491 traction force, 491 viscoelastic properties, 490 lumbar positional forward-bent position, 493–494 leaning, 495 protective scoliosis, 494 spinal mechanics, 493 traction, 493–494,494f unilateral foramen opening, 493 unilateral traction, 494 muscular system effects electromyographic recordings, 492 features, 492 nerves effects tingling, 492 unrelieved pressure on, 492 spinal movement effects, 489 intervertebral space relationships, 490 length and amount of separation, 490 therapeutic changes, 490 treatment techniques inversion, 495–496 lumbar positional, 493–495 manual cervical, 509–510 manual lumbar, 496–500 mechanical cervical, 510–511 mechanical lumbar traction, 500–508 protocols, 511–512 Standard wound care (SWC), 55 Strain–counterstrain technique, 564–565 SWC (Standard wound care), 55 T Therapeutic massage indications and contraindications, 570–571,579 physiologic effects of mechanical, 545–547,554 reflexive, 545–546,551–558,564–565,578 psychologic effects of, 547 treatment of active release technique (ART), 566,566f connective tissue, 560–561,567–569,572,578–580 considerations and guidelines, 547–551,581 friction, 557–558,572,578 Graston technique, 568–569,569f Hoffa, 551–557,563,572–573,578,580 myofascial release, 566–568,572,578 positional release therapy, 565 rolfing, 568–570,572,578 strain–counterstrain, 564–565 Trager system, 570,572,578 transverse friction, 558–560,573,580 trigger point, 561–564,572–573,580–581 Therapeutic modulaties, 3,4t mechanism of action, 5 Therapeutic ultrasound acoustic energy in biologic tissues, transmission attenuation, 365–367 transverse/longitudinal waves, 364 velocity, 365 wave transmission, frequency of, 364–365 basic physics of generator, components of, 365–375 bladder technique, 385f Aquaflex gel pad, 385 balloon, surgical glove, 384 bone healing assessing stress fractures, 390 calcium deposits, absorption of, 390 ultrasonic growth stimulators, 389–390 case study knee motion restriction, 392 wrist capsule motion restriction, 391–392 chronic inflammation epicondylitis, 389 tendinitis and bursitis, 389 clinical applications bone healing, 389–390 chronic inflammation, 389 connective tissue, stretching of, 387–389 pain reduction, 391 placebo effects, 391–392 plantar warts, 391 scar tissue, joint contracture, 387 soft-tissue healing, repair, 386–387 cold packs decreasing superficial attenuation, 396 temperature changes in deep muscles, 396 in combination with other modalities cold packs, 396–397 electrical stimulation, 397–398 hot packs, 396 treatment goal, 395 connective tissue stretching friction massage, joint mobilization, 389 prevent musculotendinous injury, 387 rate of temperature decay, 388 coupling methods checking relative transmission capability of medium, 381 water soluble gels, 380 depth of penetration, 379 desired temperature, 378 diagnostic musculoskeletal, 363 direct contact actual contact between applicator and skin, 381 decrease pain perception, 382 through gel-like coupling medium, 382 electrical stimulation moderate increase in tissue temperature, 398 transducer serves as one electrode, 397 vectorsonic combi, 397 exposure techniques bladder, 384 direct contact, 381–382 immersion, 383 moving transducer, 384–385 recording treatments, 385 frequency of treatment acute conditions, 378 heating modality deep heating modality, 364 hot packs reducing muscle spasm, 396 immersion bony prominences, 383 moving transducer autosound, 386 beam nonuniformity ratio (BNR)-dependent, 385 stationary technique, 384 pain reduction large-diameter myelinated nerve fibers, 391 phonophoresis decreasing levels of perceived pain, 395 enhanced delivery of selected medication, 393 hydrocortisone, cortisol, salicylates, 393 salicylates enhances analgesic, 393 transmission by media, 394t physiologic effects nonthermal, 376–378 thermal, 375–376 placebo effects, 391 plantar warts weight-bearing areas, 391 precautions contraindicated during pregnancy, 398 high spatial-averaged temporal peak intensity, 398 safely over metal implants, 398 vascular problems involving thrombophlebitis, 398 protocols, 383–384 rate of heating, 380 safe use of equipment, guidelines Federal Performance Standards, 398 indications and contraindications, 399t treatment protocol, 400 scar tissue, joint contracture Dupuytren’s contracture, 387 tensile stresses and strains, 387 soft-tissue healing, repair accelerated by both thermal and nonthermal, 386 enhancing postexercise muscle strength recovery, 387 proinflammatory, 387 treatment techniques coupling methods, 380–381 duration of, 378–380 exposure, 381–386 frequency of, 378 ultrasonic bone growth stimulators current, 389 pulsating electromagnetic field (PEMF), 389–390 Therapeutic ultrasound generator, components amplitude, power, intensity magnitude of vibration, 372,373f patient tolerance, 374 spatial-averaged, 373 spatial peak, 373 temporal peak, 373 anatomy of transducer, 367f beam nonuniformity ratio, 372 frequency, 370 near field and far field, 372 penetration of deeper tissues, 371 pulsed and continuous wave duty cycle, 374 pulse period, 375 state-of-the-art “ultimate” machine, features, 368t transducer effective radiating area, 369–370 mechanical deformation of crystal, 369 piezoelectric effect, 367,369f units, 368f ThermaCare wraps applied to lower back, 321f clothlike material, 320 Thermal energy, 4,12 modalities cryotherapy, 13 thermotherapy, 13 Thermotherapy treatment techniques, 4 commercial hydrocollator packs, 315f application, 315–316 considerations for use of, 315 physiologic responses, 315 storage in tank, 315 sufficient toweling, 315 unit heat packs, 315 fluidotherapy application, 319–320 considerations for use of, 319 mechanoreceptor, thermoreceptor stimulation, 319 multifunctional physical medicine modality, 318 physiologic responses, 319 protective toweling, 319 protocols, 320 upper extremity, 319f infrared lamps application, 322 considerations for use of, 322 electromagnetic energy modality, 320 ground-fault interrupter (GFI), 321 heating lamp, 321 luminous and nonluminous, 320 physiologic responses, 322 positioning of, 321 protocols, 322 not for patient with edema, 312 paraffin baths application, 317–318 considerations for use of, 317 hand dipping, 317 high degree of localized heat, 316f physiologic responses, 317 plastic bags, paper towels, 317 protocols, 318 wrapping, 317 thermaCare wraps applied to lower back, 321 clothlike material, 320 warm whirlpool, 313f application, 313–315 considerations for use of, 313 padding, 313 positioning patient comfortably, 313 Tissue cooling See Cryotherapy treatment techniques, tissue cooling Trager system, 570 Transcutaneous electrical nerve stimulation (TENS), 42 Transverse friction massage, 558–559 Trigger point massage clinical characteristics, 562–563 myofascial, 561–562 techniques, 563 treatment protocol, 562 U Ultrasound nonthermal cavitation and acoustic microstreaming, 376 modulate membrane properties, 377 unidirectional movement of fluids, 377 physiologic effects biophysical, 375,377f thermal nonacoustic heating modalities, 376 tissue temperature increase, 375 and wound healing action of, 46–47 application technique, 48–49,49f fibroblast, 47 nitric oxide (NO) metabolism, 47 physical effects of, 47 researches on, 47–48 sound waves, 48–49 temporal pattern of changes, 47 ultrasound mist therapy, 49 Ultraviolet light and wound healing antibacterial effect of, 52 application methods for, 52–53,53f carcinogenic effects, 54 treatment protocols, 53 ultraviolet light C, 51–52 vancomycin-resistant Enterococcus faecalis (VRE), 52 in vitro, 52 wound bed preparation of, 53f Uninflated compression appliance, 532 Units of measure, 587 V Vascular endothelial growth factor (VEGF), 47 Vibration technique, 556 Vital Wrap, 536 W Warm whirlpool See also Thermotherapy treatment techniques application, 313–315 considerations for use of, 313 padding, 313 positioned comfortably, 313 Wound healing cellular and physiological processes, 37 clinical research evidence, 54 application of superficial heat, 56 case reports, 56–57 Cochrane review, 55 hydrotherapy, 56 reports, 55 standard wound care (SWC), 55 studies, 55 trials, 55–56 defined, 37 electrical stimulation adverse effects, 45 application technique, 42–43,45 case study, 45–46 electrical currents, 45 endogenous bioelectrical potentials, 40 epithelial cell activity, 41 experimental research, 41 high-voltage pulsed current (HVPC), 41 inflammatory cells activity, 40–41 intracellular mechanisms, 41 low-intensity direct current (LIDC), 44 results, 41 spinal cord injury (SCI), 42 stimulus parameters, 43–44 studies on, 44 transcutaneous electrical nerve stimulation (TENS), 42 treatment schedules, 44–45 in vitro studies, 40 wound bed preparation, 43 hot and cold agents, on blood flow effects of elevation of local tissue temperature, 38 methicillin-resistant Staphylococcus aureus (MRSA), 38 tissue temperature, 38–39 vasoconstriction of cutaneous arterioles, 38 hydrotherapy and benefits of, 39 cleansing, 39 elevating water temperature, 39 foreign matter removal, 39 nonimmersion techniques, 39 protocols for, 40 Pseudomonas aeruginosa, 40 impairments in soft tissue, 37–38 laser on tissue repair, effects of, 49–51 pneumatic compression therapy, 54 external pressure administration, 54 treatment of nonhealing wounds contraindications, 58t–59t hydrotherapy, 57–58 pneumatic compression therapy, 58 ultrasound, 57 ultraviolet light C, 57 wound bed preparation, 57 ultrasound and action of, 46–47 application technique, 48–49 fibroblast, 47 nitric oxide (NO) metabolism, 47 physical effects of, 47 researches on, 47–48 sound waves, 48–49 temporal pattern of changes, 47 ultrasound mist therapy (MIST), 49 vascular endothelial growth factor (VEGF), 47 ultraviolet light and antibacterial effect of, 52 application methods for, 52–53 carcinogenic effects, 54 treatment protocols, 53 ultraviolet light C, 51–52 vancomycin-resistant Enterococcus faecalis (VRE), 52 in vitro, 52 wound bed preparation of, 53 1 The authors would like to thank Dr Brian G Ragan from the University of Northern Iowa for his contribution of this section to the chapter ... pulsed sound beam with a duty cycle of 20 % with a temporal peak intensity of 2. 0 W/cm2, temporal-averaged intensity would be 0.4 W/cm2 It should be pointed out that on some machines, the intensity setting indicates the temporal... similar to other forms of heat that may be applied, including the following:37 An increase in the extensibility of collagen fibers found in tendons and joint capsules Decrease in joint stiffness Reduction of muscle spasm Modulation of pain Increased blood flow... Spatial-averaged temporal peak (SATP) intensity is the maximum intensity occurring in time of the spatially averaged intensity The SATP intensity is simply the spatial average during a single pulse Figure 10–9 In continuous ultrasound, energy is constantly being generated