Physical Agents in Rehabilitation: An Evidence-Based Approach to Practice PDF

Physical Agents in Rehabilitation An Evidence-Based Approach to Practice FIFTH EDITION Michelle H. Cameron, MD, PT, MCR Associate Professor Department of Neurology Oregon Health & Science University; MS Fellowship Director MS Center of Excellence-West VA Portland Health Care System; Owner Health Potentials Portland, Oregon 2 Table of Contents Cover image Title Page Copyright Biography Acknowledgments Contributors Preface Part I Introduction to Physical Agents 1 The Physiology of Physical Agents How to Use This Book What Are Physical Agents? Categories of Physical Agents Effects of Physical Agents General Contraindications and Precautions for Physical Agent Use 3 Evaluation and Planning for the Use of Physical Agents Documentation Chapter Review Glossary References 2 Physical Agents in Clinical Practice History of Physical Agents in Medicine and Rehabilitation Approaches to Rehabilitation The Role of Physical Agents in Rehabilitation Practitioners Using Physical Agents Evidence-Based Practice Using Physical Agents Within Different Health Care Delivery Systems Chapter Review Glossary References Part II Pathology and Patient Problems 3 Inflammation and Tissue Repair Phases of Inflammation and Healing Chronic Inflammation Factors Affecting the Healing Process Healing of Specific Musculoskeletal Tissues Chapter Review 4 Glossary References 4 Pain and Pain Management Pain, Nociception, and the Nociceptive System Types of Pain Measuring Pain Pain Management Chapter Review Glossary References 5 Tone Abnormalities Muscle Tone Tone Abnormalities Measuring Muscle Tone Anatomical Bases of Muscle Tone and Activation Abnormal Muscle Tone and Its Consequences Chapter Review Glossary References 6 Motion Restrictions Types of Motion Patterns of Motion Restriction 5 Tissues That Can Restrict Motion Pathologies That Can Cause Motion Restriction Examination and Evaluation of Motion Restrictions Contraindications and Precautions to Range-of-Motion Techniques Treatment Approaches for Motion Restrictions Role of Physical Agents in the Treatment of Motion Restrictions Chapter Review Glossary References Part III Thermal Agents 7 Introduction to Thermal Agents Specific Heat Modes of Heat Transfer Chapter Review Glossary 8 Superficial Cold and Heat Cryotherapy Thermotherapy References 9 Ultrasound Introduction Effects of Ultrasound 6 Clinical Indications for Ultrasound Contraindications and Precautions for Ultrasound Precautions for Ultrasound Adverse Effects of Ultrasound Application Technique Documentation Chapter Review Glossary References 10 Diathermy Physical Properties of Diathermy Types of Diathermy Applicators Effects of Diathermy Clinical Indications for Diathermy Contraindications and Precautions for Diathermy Adverse Effects of Diathermy Application Technique Documentation Chapter Review Glossary References Part IV Electrical Currents 7 11 Introduction to Electrotherapy Electrical Current Devices, Waveforms, and Parameters Effects of Electrical Currents Contraindications and Precautions for Electrical Currents Adverse Effects of Electrical Currents Application Technique Documentation Chapter Review Glossary References 12 Electrical Currents for Muscle Contraction Effects of Electrically Stimulated Muscle Contractions Clinical Applications of Electrically Stimulated Muscle Contractions Contraindications and Precautions for Electrically Stimulated Muscle Contractions Application Techniques Documentation Chapter Review Glossary References 13 Electrical Currents for Pain Control Mechanisms Underlying Electrical Current Use for Pain Control Clinical Applications of Electrical Currents for Pain Control 8 Contraindications and Precautions for Electrical Currents for Pain Control Adverse Effects of Transcutaneous Electrical Nerve Stimulation Application Technique Documentation Chapter Review Glossary References 14 Electrical Currents for Soft Tissue Healing Mechanisms Underlying Electrical Currents for Tissue Healing Clinical Applications of Electrical Stimulation for Soft Tissue Healing Contraindications and Precautions for Electrical Currents for Tissue Healing Adverse Effects of Electrical Currents for Tissue Healing Application Techniques Documentation Chapter Review Glossary References 15 Electromyographic (EMG) Biofeedback Introduction Physiological Effects of EMG Biofeedback Clinical Indications for EMG Biofeedback Contraindications and Precautions for EMG Biofeedback Adverse Effects of EMG Biofeedback 9 Application Technique Documentation Chapter Review Glossary References Part V Electromagnetic Agents 16 Lasers and Light Introduction Physiological Effects of Lasers and Light Clinical Indications for Lasers and Light Contraindications and Precautions for Lasers and Light Adverse Effects of Lasers and Light Application Technique Documentation Chapter Review Glossary References 17 Ultraviolet Therapy Physical Properties of Ultraviolet Radiation Effects of Ultraviolet Radiation Clinical Indications for Ultraviolet Radiation Contraindications and Precautions for Ultraviolet Radiation 10 Adverse Effects of Ultraviolet Radiation Application Techniques Documentation Ultraviolet Lamps Chapter Review Glossary References Part VI Mechanical Agents 18 Hydrotherapy Physical Properties of Water Physiological Effects of Hydrotherapy Clinical Indications for Hydrotherapy Contraindications and Precautions for Hydrotherapy and Negative Pressure Wound Therapy Adverse Effects of Hydrotherapy Adverse Effects of Negative Pressure Wound Therapy Application Techniques Safety Issues Regarding Hydrotherapy Documentation Chapter Review Glossary References 19 Traction 11 Effects of Traction Clinical Indications for Traction Contraindications and Precautions for Traction Adverse Effects of Spinal Traction Application Techniques Documentation Chapter Review Glossary References 20 Compression Effects of External Compression Clinical Indications for External Compression Contraindications and Precautions for External Compression Adverse Effects of External Compression Application Techniques Documentation Chapter Review Glossary References Appendix Index 12 Copyright 3251 Riverport Lane St. Louis, Missouri 63043 PHYSICAL AGENTS IN REHABILITATION: AN EVIDENCE-BASED APPROACH TO PRACTICE, FIFTH EDITION ISBN: 978-0-323-44567-2 Copyright © 2018 by Elsevier, Inc. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Details on how to seek permission, further information about the Publisher's permissions policies and our arrangements with organizations such as the Copyright Clearance Center and the Copyright Licensing Agency, can be found at our website: www.elsevier.com/permissions. This book and the individual contributions contained in it are protected under copyright by the Publisher (other than as may be noted herein). Notices Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using any information, methods, compounds or experiments described herein. Because of rapid advances in the medical sciences, in particular, independent verification of diagnoses and drug dosages should be made. To the fullest extent of the 13 law, no responsibility is assumed by Elsevier, authors, editors or contributors for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions, or ideas contained in the material herein. Previous editions copyrighted 2013, 2009, and 2003. International Standard Book Number: 978-0-323-44567-2 Content Strategist: Lauren Willis Senior Content Development Manager: Ellen Wurm-Cutter Associate Content Development Specialist: Laura Klein Publishing Services Manager: Julie Eddy Senior Project Manager: David Stein Design Direction: Brian Salisbury Cover Designer: Linda Beaupre Text Designer: Brian Salisbury Printed in Canada Last digit is the print number: 9 8 7 6 5 4 3 2 1 14 Biography Michelle H. Cameron, MD, PT, MCR, the primary author of Physical Agents in Rehabilitation: An Evidence-Based Approach to Practice, is a physical therapist and a physician as well as an educator, researcher, and author. After 10 years working as a clinical physical therapist and teaching rehabilitation providers about physical agents, Michelle furthered her own education through medical training. She now works as a neurologist focusing on the clinical care of people with multiple sclerosis and on research to optimize mobility in people with multiple sclerosis, while continuing to write and teach about the use of physical agents in rehabilitation. Michelle is the co-editor of the texts Physical Rehabilitation: Evidence-Based Examination, Evaluation, and Intervention and Physical Rehabilitation for the Physical Therapist Assistant. Michelle has written and edited many articles on electrical stimulation, ultrasound and phonophoresis, laser light therapy and wound management, and wrote the section on ultrasound in Saunders' Manual for Physical Therapy 15 Practice. Michelle's discussions of physical agents bring together current research and practice to provide the decision-making and hands-on tools to support optimal care within today's health care environment. 16 Acknowledgments First and foremost, I want to thank the instructors who use this book in the classroom and the readers and purchasers of the previous editions of this book. Without you, this book would not exist. In particular, I would like to thank those readers who took the time to contact me with their comments, thoughts, and suggestions about what worked for them and what could be improved. I would also like to give special thanks to Ashley L. Shea, Editorial Research Assistant, for her help with updating this edition of the book. Her skills as a librarian were invaluable in bringing this edition in line with the most up-to-date approaches to applying evidence to clinical practice. Her dedication to precision and organization also ensured that all the parts came together as a whole. I would also like to thank Megan Fennell, Brian Loehr, and Laura Klein, Content Development Specialists at Elsevier, for their support throughout this project; David Stein, Senior Project Manager at Elsevier, for catching all my errors and making me look like a better writer than I am; Diane Allen, Linda Monroe, Bill Rubine, Sara Shapiro, and Gail Widener, contributing authors to this and previous editions, who updated their respective chapters thoroughly and promptly; Xiao-Yue Han and Vernon Cowell for their update of Chapter 3 on inflammation and tissue repair; Tony Rocklin for his contributions on hip traction for Chapter 19 on traction; and particularly Jason Bennett for Chapter 15 on electromyographic (EMG) biofeedback, which is new to this edition. Thank you all, Michelle H. Cameron 17 Contributors Diane D. Allen PhD, PT Professor Physical Therapy and Rehabilitation Science University of California San Francisco; San Francisco State University San Francisco, California Jason E. Bennett PhD, PT, SCS, ATC Assistant Professor Physical Therapy Department Carroll University Waukesha, Wisconsin Vernon Lee Cowell Jr., MD, MPH, CPH, FACS Surgeon Legacy Medical Group—General Surgery Legacy Mount Hood Medical Center Gresham, Oregon Xiao-Yue Han BS, MD Candidate Oregon Health and Science University Portland, Oregon Eve L. Klein MD Affiliate Assistant Professor Division of General Internal Medicine and Geriatrics Oregon Health and Science University Portland, Oregon 18 Linda G. Monroe PT, MPT, OCS Adjunct Instructor Department of Occupational Therapy Samuel Merritt University Oakland, California; Physical Therapist John Muir Physical Rehabilitation Services John Muir Health Walnut Creek, California Michelle Ocelnik MA, ATC, CSCS Director of Education and Research VQ OrthoCare Irvine, California Julie A. Pryde MS, PA-C, PT, OCS, SCS, ATC, CSCS Senior Physician Assistant Orthopedics Muir Orthopedic Specialists Walnut Creek, California Tony Rocklin PT, DPT, COMT Director of Physical Therapy Therapeutic Associates Downtown Portland Physical Therapy Portland, Oregon William Rubine MS, PT Physical Therapist Comprehensive Pain Center Oregon Health and Science University Portland, Oregon Sara Shapiro MPH, PT Educator, Pediatric Private Practice Apex Health Solutions Olympia, Washington 19 Ashley L. Shea MS Librarian Albert R. Mann Library Cornell University Ithaca, New York Gail L. Widener PhD, PT Professor Department of Physical Therapy Samuel Merritt University Oakland, California 20 Preface By writing the first edition of this book I tried to meet a need that I believed existed—the need for a book on the use of physical agents in rehabilitation that covered the breadth and depth of this material in a readily accessible, systematic, and easily understood manner. I produced a text that leads the reader from the basic scientific and physiological principles underlying the application of physical agents to the research evaluating their clinical use, and then to the practical details of selecting and applying each specific physical agent to optimize patient outcomes. The enthusiasm with which the previous editions of this book have been received—including compliments from readers, adoption by many educational programs, and purchase by many clinicians, educators and students—demonstrates that the need was there and was met. In all the subsequent editions I have done my best to keep the best from previous editions while bringing the reader new and updated information, further clarifying the presented material, and improving information accessibility. Each edition of this book provides easy-to- follow guidelines for safe application of all physical agents, as well as the essential scientific rationale and evidence-base to select and apply interventions with physical agents safely and effectively. As the quantity of research has increased, along with the quality, this text has become even more important for making clinical decisions. To keep up with the pace of research, new developments in the field of rehabilitation, and technological advances in information delivery, I have added a number of new features to this edition. The most significant new features in this edition of Physical Agents in Rehabilitation are an updated approach to presenting and accessing current evidence and the addition of a chapter on EMG biofeedback (Chapter 15). In previous editions I tried to summarize and reference all the 21 evidence on the use of physical agents in rehabilitation. With the exponential growth of research and publication, this has become impossible for me and would be unwieldy for the reader. In addition, with the increased access to information and the growing search skills of clinicians, this has become unnecessary. Therefore in this edition I have focused on high-quality evidence and on guiding readers to search for specific evidence related to their individual patients. The section on evidence-based practice in Chapter 2 has been expanded to more fully explain how the quality of a study can be assessed and how to search for relevant research using the PICO (Patient, Intervention, Comparison, Outcome) framework. Then, in all the chapters on physical agents the most recent systematic reviews and meta-analyses and subsequent large- scale randomized controlled trials are summarized and referenced. The case studies also have sample Medline search strategies using the PICO framework, with live links for the results, and summaries of key studies and reviews, to demonstrate how the reader can search for the most up- to-date evidence for a specific patient presentation. The new chapter on EMG biofeedback (Chapter 15) was added in response to consistent feedback and requests from instructors and other readers. EMG biofeedback, which involves the use of a device to detect electrical activity in muscles to give feedback to patients about the quantity and timing of muscle activity, is now included in most courses on physical agents. This chapter has the same structure as other chapters in this book and focuses on the use of EMG biofeedback for neuromuscular facilitation, inhibition, and coordination. I am sure you will find it clear and that it meets your needs for a thorough up-to-date summary of the use of EMG biofeedback in rehabilitation. In addition to the bigger changes, I have also made some smaller but significant changes to this text. I have kept electronic resources for instructors, students, and other readers. The entire text is available as an eBook and has a companion Evolve site with additional resources for both instructors and students (http://evolve.elsevier.com/Cameron/Physical). The instructor resources include PowerPoint Presentations for each chapter and an Image Collection. The student resources include PICO charts from the case studies in each chapter with live links for the Medline search strategies 22 and results; review questions for each chapter; references from each chapter linked to Medline; and the Electrical Stimulation, Ultrasound, and Laser Light Handbook, which can be printed and used as a clinical quick reference guide. The entire text has also been updated with more consistent clinical pearls, a new modern look, and some new illustrations. Some chapters have undergone larger-scale revisions. The chapters on inflammation and tissue repair (Chapter 3) and pain (Chapter 4) have been revised more substantially to reflect changes in current knowledge. The chapters on electrical stimulation (Chapters 11 through 14) have been thoroughly revised to improve clarity. Information on hip traction, with a newly invented mechanical hip traction device, has been added to the chapter on traction (Chapter 19). Welcome to the fifth edition of Physical Agents in Rehabilitation! 23 PA R T I Introduction to Physical Agents OUTLINE 1 The Physiology of Physical Agents 2 Physical Agents in Clinical Practice 24 The Physiology of Physical Agents CHAPTER OUTLINE How to Use This Book What Are Physical Agents? Categories of Physical Agents Thermal Agents Mechanical Agents Electromagnetic Agents Effects of Physical Agents Inflammation and Healing Pain Collagen Extensibility and Motion Restrictions Muscle Tone General Contraindications and Precautions for Physical Agent Use Pregnancy Malignancy Pacemaker or Other Implanted Electronic Device Impaired Sensation and Mentation Evaluation and Planning for the Use of Physical Agents Choosing a Physical Agent 25 Attributes to Consider in the Selection of Physical Agents Using Physical Agents in Combination With Each Other or With Other Interventions Documentation Chapter Review Glossary References 26 How to Use This Book This book is intended primarily as a course text for those learning to use physical agents in rehabilitation. It was written to meet the needs of students learning about the theory and practice of applying physical agents and to help practicing rehabilitation professionals review and update their knowledge. This book describes the effects of physical agents, provides guidelines on when and how physical agents can be most effectively and safely applied and when they should be avoided, and describes the outcomes that can be expected from integrating physical agents within a program of rehabilitation. The book covers the theory underlying the application of each agent and the physiological processes the agent influences, the research concerning its effects, and the rationale for the treatment recommendations. Chapters include case studies with sample online PubMed search strategies used to identify relevant research, with live links to MEDLINE in the electronic version of the book. After reading this book, the reader should be able to integrate the ideal physical agents and intervention parameters within a complete rehabilitation program to promote optimal patient outcomes. Readers should also feel confident structuring independent search strategies to locate relevant literature in PubMed, a freely accessible, constantly updated search engine that provides access to MEDLINE, a database of biomedical and allied health literature maintained by the U.S. National Library of Medicine. This book's recommendations regarding the clinical use of physical agents integrate concepts from a variety of sources, including the American Physical Therapy Association's Guide to Physical Therapist Practice 3.0 (Guide 3.0).1 Guide 3.0, a normative model of physical therapist professional practice, encompasses the standards for quality assessment; professional conduct; evidence-based practice; and the International Classification of Functioning, Disability and Health (ICF) model of the World Health Organization (WHO). Guide 3.0 is widely used by physical therapists and physical therapist assistants. In this book, particular attention is paid to the principles of evidence-based 27 practice and to the components of the ICF model in selecting and applying physical agents. The ICF is used to consider and describe the impact of physical agent interventions on patient outcomes, highlighting the components of the physical therapist patient/client management model. This model was developed in 2001 as an approach to describing functional abilities and differences and has been adopted globally, particularly among rehabilitation professionals.2 Specific recommendations presented throughout this book are derived from the best available evidence on the physiological effects and clinical outcomes of physical agents, and the search strategies used to locate the evidence are shared. The book is divided into six parts: Part I: Introduction to Physical Agents includes this introductory chapter, followed by a chapter introducing the physiological effects of physical agents and their clinical use by various professionals. Part II: Pathology and Patient Problems starts with a chapter on inflammation and tissue repair, followed by individual chapters on pain, tone abnormalities, and motion restrictions. Part III: Thermal Agents covers thermal agents including superficial cold and heat, ultrasound, and diathermy. Part IV: Electrical Currents starts with a chapter that describes the physical properties of electrical currents. This is followed by individual chapters on the use of electrical stimulation (ES) for muscle contraction, pain control, and tissue healing and a new chapter on electromyographic (EMG) biofeedback. Part V: Electromagnetic Agents discusses lasers, light, and ultraviolet (UV) therapy. Part VI: Mechanical Agents covers hydrotherapy, traction, and compression. The book also has a companion website with materials for students and other readers and additional materials for course instructors only. 28 All readers can access tables from parts II through VI of the book with sample MEDLINE searches for relevant evidence, an important addition to the site for this edition. The Electrical Stimulation, Ultrasound, and Laser Light Handbook; hyperlinks to all cited references in PubMed; review exercises; and practice tests continue to be available online to all readers. In addition, course instructors have access to PowerPoint slide sets, images, and test banks for all chapters. 29 What Are Physical Agents? Physical agents consist of energy and materials applied to patients to assist in their rehabilitation. Physical agents include heat, cold, water, pressure, sound, electromagnetic radiation, and electrical currents. The term physical agent can be used to describe the general type of energy, such as electromagnetic radiation or sound; a specific range within the general type, such as ultraviolet (UV) radiation or ultrasound; and the actual means of applying the energy, such as a UV lamp or an ultrasound transducer. The terms physical modality, biophysical agent, physical agent modality, electrophysical agent, and modality are frequently used in place of the term physical agent and are used interchangeably in this book. Clinical Pearl Physical agents are energy and materials applied to patients to assist in their rehabilitation. Physical agents include heat, cold, water, pressure, sound, electromagnetic radiation, and electrical currents. 30 Categories of Physical Agents Physical agents can be categorized as thermal, mechanical, or electromagnetic (Table 1.1). Thermal agents include superficial-heating agents, deep-heating agents, and superficial-cooling agents. Mechanical agents include traction, compression, water, and sound. Electromagnetic agents include electromagnetic fields and electrical currents. Some physical agents fall into more than one category. Water and ultrasound, for example, can have mechanical and thermal effects. TABLE 1.1 Categories of Physical Agents Category Types Clinical Examples Thermal Deep-heating agents Ultrasound, diathermy Superficial heating agents Hot pack Cooling agents Ice pack Mechanical Traction Mechanical traction Compression Elastic bandage, stockings Water Whirlpool Sound Ultrasound Electromagnetic Electromagnetic fields Ultraviolet, laser Electrical currents TENS TENS, Transcutaneous electrical nerve stimulation. Thermal Agents Thermal agents transfer energy to a patient to increase or decrease tissue temperature. Examples include hot packs, ice packs, ultrasound, whirlpool, and diathermy. Cryotherapy is the therapeutic application of cold, whereas thermotherapy is the therapeutic application of heat. Depending on the thermal agent and the body part to which it is applied, temperature changes may be superficial or deep and may affect one type of tissue more than another. For example, a hot pack produces the greatest temperature increase in superficial tissues with high thermal conductivity in the area directly below it. In contrast, ultrasound produces heat in deeper tissues and produces the most heat in tissues having high ultrasound absorption coefficients, such as tendon and 31 bone. Diathermy, which involves applying shortwave or microwave electromagnetic energy, heats deep tissues having high electrical conductivity. Thermotherapy is used to increase circulation, metabolic rate, and soft tissue extensibility or to decrease pain. Cryotherapy is applied to decrease circulation, metabolic rate, or pain. A full discussion of the principles underlying the processes of heat transfer; the methods of heat transfer used in rehabilitation; and the effects, indications, and contraindications for applying superficial heating and cooling agents is provided in Chapter 8. The principles and practice of applying deep- heating agents are discussed in Chapter 9 in the section on thermal applications of ultrasound and in Chapter 10 in the section on diathermy. Ultrasound is a physical agent that has both thermal and nonthermal effects. Ultrasound is defined as sound with a frequency greater than 20,000 cycles/second—too high to be heard by humans. Ultrasound is a mechanical form of energy composed of alternating compression and rarefaction waves. Thermal effects, including increased deep and superficial tissue temperature, are produced by continuous ultrasound waves of sufficient intensity, and nonthermal effects are produced by both continuous and pulsed ultrasound. Continuous ultrasound is used to heat deep tissues to increase circulation, metabolic rate, and soft tissue extensibility and to decrease pain. Pulsed ultrasound is used to facilitate tissue healing or to promote transdermal drug penetration by nonthermal mechanisms. Further information on the theory and practice of applying ultrasound is provided in Chapter 9. Mechanical Agents Mechanical agents apply force to increase or decrease pressure on the body. Examples of mechanical agents include water, traction, compression, and sound. Water can provide resistance, hydrostatic pressure, and buoyancy for exercise or can apply pressure to clean wounds. Traction decreases the pressure between structures, whereas compression increases the pressure on and between structures. Ultrasound is discussed in the previous section. The therapeutic use of water is called hydrotherapy. Water can be 32 applied with or without immersion. Immersion in water increases pressure around the immersed area, provides buoyancy, and, if there is a difference in temperature between the immersed area and the water, transfers heat to or from that area. Movement of water produces local pressure that can be used as resistance for exercise when an area is immersed and for cleansing or debriding open wounds with or without immersion. Further information on the theory and practice of hydrotherapy is provided in Chapter 18. Traction is most commonly used to alleviate pressure on structures such as nerves or joints that produce pain or other sensory changes or that become inflamed when compressed. Traction can normalize sensation and prevent or reduce damage or inflammation of compressed structures. The pressure-relieving effects of traction may be temporary or permanent, depending on the nature of the underlying pathology and the force, duration, and means of applying traction. Further information on the theory and practice of applying traction is provided in Chapter 19. Compression is used to counteract fluid pressure and to control or reverse edema. The force, duration, and means of applying compression can be varied to control the magnitude of the effect and to accommodate different patient needs. Further information on the theory and practice of applying compression is provided in Chapter 20. Electromagnetic Agents Electromagnetic agents apply energy in the form of electromagnetic radiation or an electrical current. Examples of electromagnetic agents include UV radiation, infrared (IR) radiation, laser, diathermy, and electrical current. Variation of the frequency and intensity of electromagnetic radiation changes its effects and depth of penetration. For example, UV radiation, which has a frequency of 7.5 × 1014 to 1015 cycles/second (Hertz [Hz]), produces erythema and tanning of the skin but does not produce heat, whereas IR radiation, which has a frequency of 1011 to 1014 Hz, produces heat only in superficial tissues. Lasers output monochromatic, coherent, directional electromagnetic radiation that is generally in the frequency range of visible light or IR radiation. Continuous shortwave diathermy, which has a frequency of 105 to 106 33 Hz, produces heat in both superficial and deep tissues. When shortwave diathermy is pulsed (pulsed shortwave diathermy [PSWD]) to provide a low average intensity of energy, it does not produce heat. This intervention is now known as nonthermal shortwave therapy (SWT). SWT is thought to modify cell membrane permeability and cell function by nonthermal mechanisms and thereby control pain and edema. These agents are thought to facilitate healing via biostimulative effects on cells. Further information on the theory and practice of applying electromagnetic radiation and on lasers and other forms of light is provided in Chapter 16. UV radiation and diathermy are discussed in Chapters 17 and 10, respectively. Electrical stimulation (ES) is the use of electrical current to induce muscle contraction (motor-level ES) and changes in sensation (sensory- level ES), reduce edema, or accelerate tissue healing. The effects and clinical applications of electrical currents vary according to the waveform, intensity, duration, and direction of the current flow and according to the type of tissue to which the current is applied. Electrical currents of sufficient intensity and duration can depolarize nerves, causing sensory or motor responses that may be used to control pain or increase muscle strength and control. Electrical currents with an appropriate direction of flow can attract or repel charged particles and alter cell membrane permeability to control the formation of edema, promote tissue healing, and facilitate transdermal drug penetration. Muscle contractions are associated with changes in ionic activity. This activity can be detected by EMG electrodes placed on the skin and can be fed back to the patient to facilitate or inhibit muscle activity. This is known as EMG biofeedback. Further information on the theory and practice of electrical current and EMG biofeedback application is provided in Part IV. 34 Effects of Physical Agents The application of physical agents primarily reduces tissue inflammation, accelerates tissue healing, relieves pain, alters collagen extensibility, or modifies muscle tone. A brief review of these processes follows; more complete discussions of these processes are provided in Chapters 3 through 6. A brief discussion of physical agents that modify each of these conditions is included here, and the chapters in Parts III through VI of this book cover each of the physical agents in detail. Clinical Pearl The application of physical agents primarily reduces tissue inflammation, accelerates tissue healing, relieves pain, alters collagen extensibility, or modifies muscle tone. Inflammation and Healing When tissue is damaged, it usually responds predictably. Inflammation is the first phase of recovery, followed by the proliferation and maturation phases. Modifying this healing process can accelerate rehabilitation and reduce adverse effects such as prolonged inflammation, pain, and disuse. This in turn leads to improved patient function and more rapid achievement of therapeutic goals. Thermal agents modify inflammation and healing by changing the rates of circulation and chemical reactions. Mechanical agents control motion and alter fluid flow, and electromagnetic agents alter cell function, particularly membrane permeability and transport. Many physical agents affect inflammation and healing and, when appropriately applied, can accelerate progress, limit adverse consequences of the healing process, and optimize the final patient outcome (Table 1.2). However, when poorly selected or misapplied, physical agents may impair or potentially prevent complete healing. TABLE 1.2 35 Physical Agents for Promoting Tissue Healing Stage of Tissue Contraindicated Goals of Treatment Effective Agents Healing Agents Initial injury Prevent further injury or Static compression, cryotherapy Exercise bleeding Intermittent traction Motor-level ES Thermotherapy Clean open wound Hydrotherapy (immersion or nonimmersion) Chronic Prevent/decrease joint Thermotherapy Cryotherapy inflammation stiffness Motor ES Whirlpool Fluidotherapy Control pain Thermotherapy Cryotherapy ES Laser Increase circulation Thermotherapy ES Compression Hydrotherapy (immersion or exercise) Progress to proliferation Pulsed ultrasound stage ES SWT Remodeling Regain or maintain strength Motor ES Immobilization Water exercise EMG biofeedback Regain or maintain Thermotherapy Immobilization flexibility Control scar tissue Brief ice massage formation Compression EMG, Electromyographic; ES, electrical stimulation; SWT, nonthermal shortwave therapy. During the inflammatory phase of healing, which generally lasts for 1 to 6 days, cells that remove debris and limit bleeding enter the traumatized area. The inflammatory phase is characterized by heat, swelling, pain, redness, and loss of function. The more quickly this phase is completed and resolved, the more quickly healing can proceed, and the lower the probability of joint destruction, excessive pain, swelling, weakness, immobilization, and loss of function. Physical agents generally assist during the inflammation phase by reducing circulation, reducing pain, reducing the enzyme activity rate, controlling 36 motion, and promoting progression to the proliferation phase of healing. During the proliferation phase, which generally starts within the first 3 days after injury and lasts for approximately 20 days, collagen is deposited in the damaged area to replace tissue that was destroyed by trauma. In addition, if necessary, myofibroblasts contract to accelerate closure, and epithelial cells migrate to resurface the wound. Physical agents generally assist during the proliferation phase of healing by increasing circulation and the enzyme activity rate and by promoting collagen deposition and progression to the remodeling phase of healing. During the maturation phase, which usually starts approximately 9 days after the initial injury and can last for up to 2 years, both deposition and resorption of collagen occur. The new tissue remodels itself to resemble the original tissue as closely as possible and hence continue its original function. During this phase, the healing tissue changes in both shape and structure to allow for optimal functional recovery. The shape conforms more closely to the original tissue, often decreasing in size from the proliferation phase, and the structure becomes more organized. Thus greater strength is achieved with no change in tissue mass. Physical agents generally assist during the maturation phase of healing by altering the balance of collagen deposition and resorption and improving the alignment of new collagen fibers. Physical Agents for Tissue Healing The stage of tissue healing determines the goals of intervention and the physical agents to be used. The following discussion is summarized in Table 1.2. Initial Injury. Immediately after injury or trauma, the goals of intervention are to prevent further injury or bleeding and to clean away wound contaminants if the skin has been broken. Immobilizing and supporting the injured area with a static compression device, such as an elastic wrap, a cast, or a brace, or reducing stress on the area using assistive devices such as crutches can limit further injury and bleeding. Motion of the injured area, whether active, electrically stimulated, or passive, is 37 contraindicated at this stage because it can further damage tissue and increase bleeding. Cryotherapy helps control bleeding by limiting blood flow to the injured area by constricting vessels and increasing the blood's viscosity.3,4 Thermotherapy is contraindicated at this early stage because it can increase bleeding at the site by increasing the blood flow or reopening vascular lesions through vasodilation.5-7 Nonimmersion hydrotherapy can be used to clean the injured area if the skin has been broken and the wound has become contaminated; however, because thermotherapy is contraindicated, only neutral-warmth or cooler water should be used.8,9 Acute Inflammation. During the acute inflammatory stage of healing, the goals of intervention are to control pain, edema, bleeding, and the release and activity of inflammatory mediators and to facilitate progression to the proliferation stage. A number of physical agents, including cryotherapy, hydrotherapy, ES, and SWT, can be used to control pain; however, thermotherapy, intermittent traction, and motor-level ES are not appropriate.10-13 Thermotherapy is not recommended because it causes vasodilation, which may aggravate edema, and it increases the metabolic rate, which may increase the inflammatory response. Intermittent traction and motor-level ES should be used with caution because the movement produced by these physical agents may further irritate tissue, thereby aggravating the inflammatory response. A number of physical agents, including cryotherapy, compression, sensory-level ES, SWT, and contrast bath, may be used to control or reduce edema.13-16 Cryotherapy and compression can also help control bleeding; furthermore, cryotherapy inhibits the activity and release of inflammatory mediators. If healing is delayed because inflammation is inhibited, which may occur in a patient who is on high-dose catabolic corticosteroids, cryotherapy should not be used because it may further impair the process of inflammation, potentially delaying tissue healing. Evidence indicates that pulsed ultrasound, laser light, and SWT may promote progression from the inflammation stage to the proliferation stage of healing.13,17,18 Chronic Inflammation. 38 If the inflammatory response persists and becomes chronic, the goals, and thus the selection of interventions, will change. During this stage of healing, the treatment goals are to prevent or decrease joint stiffness, control pain, increase circulation, and promote progression of healing to the proliferation stage. The most effective interventions for reducing joint stiffness are thermotherapy and motion.19,20 Superficial structures such as the skin and subcutaneous fascia may be heated by superficial heating agents, such as hot packs or paraffin, which is a waxy substance that is warmed and used to coat the extremities for thermotherapy. However, to heat deeper structures such as the shoulder or hip joint capsules, deep-heating agents such as ultrasound or diathermy must be used.21-24 Motion may be produced by active exercise or ES and can be combined with heat by having the patient exercise in warm water or in fluidotherapy. Thermotherapy and ES can relieve pain during the chronic inflammatory stage. However, cryotherapy generally is not recommended during this stage because it can increase the joint stiffness frequently associated with chronic inflammation. Selection between thermotherapy and ES generally depends on the need for additional benefits of each modality and on other selection factors discussed later. Circulation may be increased with thermotherapy, ES, compression, water immersion, or exercise and possibly by the use of contrast baths.5,25-28 A final treatment goal at the chronic inflammatory phase of tissue healing is to promote progression to the proliferation phase. Some studies indicate that pulsed ultrasound, electrical currents, and electromagnetic fields may promote this. Proliferation. Once the injured tissue moves beyond the inflammation stage to the proliferation stage of healing, the primary goals of intervention become controlling scar tissue formation, ensuring adequate circulation, maintaining strength and flexibility, and promoting progression to the remodeling stage. Static compression garments can control superficial scar tissue formation, promote enhanced cosmesis, and reduce the severity and incidence of contractures.29 Adequate circulation is required to provide oxygen and nutrients to newly forming tissue. Circulation may be enhanced by the use of thermotherapy, electrotherapy, 39 compression, water immersion, or exercise and possibly by the use of contrast baths. Although active exercise can increase and maintain strength and flexibility during the proliferation stage of healing, the addition of motor-level ES or water exercise may accelerate recovery and provide additional benefit. The water environment reduces loading and thus the potential for trauma to weight-bearing structures and thereby may decrease the risk of regression to the inflammatory stage.30 Support provided by the water may also assist motion should the muscles be very weak, and water-based exercise and thermotherapy may promote circulation and help maintain or increase flexibility.30,31 Maturation. During maturation, the final stage of tissue healing, the goals of intervention are to regain or maintain strength and flexibility and to control the formation of scar tissue. At this point in the healing process, injured tissues are approaching their final form. Therefore treatment should focus on reversing any adverse effects of earlier stages of healing, such as weakening of muscles or loss of flexibility through strengthening and stretching exercises. Strengthening may be more effective with the addition of motor-level ES, EMG biofeedback, or water exercise, whereas stretching may be more effective with prior application of thermotherapy or brief ice massage.32-34 If the injury is the type particularly prone to excessive scar formation, such as a burn, controlling scar formation with compression garments should be continued throughout the remodeling stage. Pain Pain is an unpleasant sensory and emotional experience associated with actual or threatened tissue damage. Pain usually protects individuals by preventing them from performing activities that would damage tissue; however, it may also interfere with normal activities and cause functional limitation and disability. For example, pain can interfere with sleep, work, or exercise. Relieving pain can allow patients to participate more fully in normal activities of daily life and may accelerate the initiation of an active rehabilitation program, thereby limiting the adverse consequences of disuse and allowing more rapid progress 40 toward the patient's functional goals. Pain may result from an underlying pathology such as joint inflammation or pressure on a nerve that is in the process of resolving or a malignancy that is not expected to fully resolve. In whichever circumstance, relieving pain may improve the patient's levels of activity and participation. Pain-relieving interventions, including physical agents, may be used for as long as pain persists but should be discontinued when pain resolves. Physical agents can control pain by modifying pain transmission or perception or by changing the underlying process that is causing the sensation. Physical agents may act by modulating transmission at the spinal cord level, changing the rate of nerve conduction, or altering the central or peripheral release of neurotransmitters. Physical agents can change the processes that cause pain by modifying tissue inflammation and healing, altering collagen extensibility, or modifying muscle tone. The processes of pain perception and pain control are examined in Chapter 4. Clinical Pearl Physical agents can control pain by modifying pain transmission, modifying perception, or changing the underlying process that is causing the sensation. Physical Agents for Pain Modulation The choice of a physical agent to treat pain depends on the type and cause of the pain (Table 1.3). TABLE 1.3 Physical Agents for the Treatment of Pain Contraindicated Type of Pain Goals of Treatment Effective Agents Agents Acute Control pain Sensory ES, cryotherapy Control inflammation Cryotherapy Thermotherapy Prevent aggravation of pain Immobilization, EMG biofeedback Local exercise, motor ES Low-load static traction 41 Referred Control pain ES, cryotherapy, thermotherapy Spinal radicular Decrease nerve root Traction inflammation Decrease nerve root compression Pain caused by Control pain ES, cryotherapy, superficial malignancy thermotherapy EMG, Electromyographic; ES, electrical stimulation. Acute Pain. For acute pain, the goals of intervention are to control the pain and associated inflammation and avoid aggravating the pain or its cause. Many physical agents, including sensory-level ES, cryotherapy, and laser light, can relieve or reduce the severity of acute pain.10-13,35 Thermotherapy may reduce the severity of acute pain; however, because acute pain is frequently associated with acute inflammation, which is aggravated by thermotherapy, this modality generally is not recommended to treat acute pain. Cryotherapy is thought to control acute pain by modulating transmission at the spinal cord, by slowing or blocking nerve conduction, and by controlling inflammation and its associated signs and symptoms. Sensory-level ES also relieves acute pain by modulating transmission at the spinal cord or by stimulating the release of endorphins. Briefly limiting motion of a painful area with the aid of a static compression device, an assistive device, or bed rest, can prevent aggravation of the symptom or cause of acute pain. Excessive movement or muscle contraction in the area of acute pain is generally contraindicated; thus exercise or motor-level ES of this area should be avoided or restricted to a level that does not exacerbate pain. As acute pain starts to resolve, controlled reactivation of the patient may accelerate pain resolution. The water environment may be used to facilitate such activity. Chronic Pain. Chronic pain is pain that does not resolve within the normal recovery time expected for an injury or disease.36 The goals of intervention for chronic pain shift from resolving the underlying pathology and controlling symptoms to promoting function, enhancing strength, and improving coping skills. Although psychological interventions are the 42 mainstay of improving coping skills in patients with chronic pain, exercise should be used to regain strength and function. The water environment may be used to improve functional abilities and the capacity of certain patients with chronic pain, and motor-level ES, EMG biofeedback, and water exercise may be used to increase muscle strength in weak or deconditioned patients. In the treatment of chronic pain, bed rest should be discouraged because it can result in weakness and further reduce function, as should passive physical agent treatments provided by a clinician because patients can become dependent on the clinician rather than improving their own coping skills. The judicious self- application of pain-controlling physical agents by patients may be indicated when this helps to improve their ability to cope with pain on a long-term basis; however, it is important that such interventions do not excessively disrupt the patient's functional activities. For example, transcutaneous electrical nerve stimulation (TENS) applied by a patient to relieve or reduce chronic back pain may promote function by allowing the patient to participate in work-related activities; however, having the patient apply a hot pack for 20 minutes every few hours would interfere with their ability to perform normal functional activities and therefore would not be recommended. Referred Pain. If the patient's pain is referred to a musculoskeletal area from an internal organ or from another musculoskeletal area, physical agents may be used to control it; however, the source of the pain should also be treated if possible. Pain-relieving physical agents such as thermotherapy, cryotherapy, or ES may control referred pain and may be particularly beneficial if complete resolution of the problem is prolonged or cannot be achieved. For example, although surgery may be needed to fully relieve pain caused by endometriosis, if the disease does not place the patient at risk, physical or pharmacological agents may be used for pain control. Radicular pain in the extremities caused by spinal nerve root dysfunction may be effectively treated by applying spinal traction or by the use of physical agents that cause sensory stimulation of the involved dermatome, such as thermotherapy, cryotherapy, or ES.37 Spinal traction 43 is effective in such circumstances because it can reduce nerve root compression, thereby addressing the source of the pain, whereas sensory stimulation may modulate the transmission of pain at the spinal cord level. Pain Caused by Malignancy. Treatment of pain caused by malignancy may differ from treatment of pain from other causes because particular care must be taken to avoid using agents that could promote the growth or metastasis of malignant tissue. Because the growth of some malignancies can be accelerated by increasing local circulation, agents such as ultrasound and diathermy, which are known to increase deep tissue temperature and circulation, generally should not be used in an area of malignancy.38,39 However, in patients with end-stage malignancies, pain-relieving interventions that can improve the patient's quality of life but may adversely affect disease progression may be used with the patient's informed consent. Complex Regional Pain Syndrome. Complex regional pain syndrome (CRPS) is pain that is believed to involve overactivation of the sympathetic nervous system. Physical agents can be used to control the pain of CRPS. In general, low-level sensory stimulation of the involved area, as can be provided by neutral warmth, mild cold, water immersion, or gentle agitation of fluidotherapy, may be effective, whereas more aggressive stimulation, such as can be provided by very hot water, ice, or aggressive agitation of fluidotherapy, probably will not be tolerated and may aggravate this type of pain. Collagen Extensibility and Motion Restrictions Collagen is the main supportive protein of skin, tendon, bone cartilage, and connective tissue. Tissues that contain collagen can become shortened as a result of being immobilized in a shortened position or being moved through a limited range of motion (ROM). Immobilization may result from disuse caused by debilitation or neural injury or may be caused by the application of an external device such as a cast, brace, or external fixator. Movement may be limited by internal derangement, 44 pain, weakness, poor posture, or an external device. Shortening of muscles, tendons, or joint capsules may cause restricted joint ROM. To return soft tissue to its normal functional length and thereby allow full motion without damaging other structures, the collagen must be stretched. Collagen can be stretched most effectively and safely when it is most extensible. Because the extensibility of collagen increases in response to increased temperature, thermal agents are frequently applied before soft tissue stretching to optimize the stretching process (Fig. 1.1).40-43 Processes underlying the development and treatment of motion restrictions are discussed in Chapter 6. FIGURE 1.1 Changes in collagen extensibility in response to changes in temperature. Physical Agents for the Treatment of Motion Restrictions Physical agents can be effective adjuncts to the treatment of motion restrictions caused by muscle weakness, pain, soft tissue shortening, or a bony block; however, appropriate interventions for these different sources of motion restriction vary (Table 1.4). TABLE 1.4 45 Physical Agents for the Treatment of Motion Restrictions Source of Motion Goals of Contraindicated Effective Agents Restriction Treatment Agents Muscle weakness Increase muscle Water exercise, motor ES, EMG biofeedback Immobilization strength Pain At rest and with Control pain ES, cryotherapy, thermotherapy, SWT, spinal Exercise motion traction, EMG biofeedback With motion only Control pain ES, cryotherapy, thermotherapy, SWT Exercise into pain Promote tissue healing Soft tissue Increase tissue Thermotherapy Prolonged shortening extensibility cryotherapy Increase tissue Thermotherapy or brief ice massage and stretch length Bony block Remove block None Stretching blocked joint Compensate Exercise Thermotherapy or brief ice massage and stretch EMG, Electromyographic; ES, electrical stimulation; SWT, nonthermal shortwave therapy. Clinical Pearl Physical agents can be effective adjuncts to the treatment of motion restrictions caused by muscle weakness, pain, soft tissue shortening, or a bony block. When active motion is restricted by muscle weakness, treatment should be aimed at increasing muscle strength. This can be achieved by repeated overload muscle contraction through active exercise and may be enhanced by exercise in water or motor-level ES. Water can provide support to allow weaker muscles to move joints through greater ROM and can provide resistance against which stronger muscles can work. Motor-level ES can preferentially train larger muscle fibers, isolate the contraction of specific muscles, and precisely control the timing and number of muscle contractions. When ROM is limited by muscle weakness alone, rest and immobilization of the area are contraindicated because restricting active use of weakened muscles will further reduce their strength, exacerbating existing motion restriction. When motion is restricted by pain, treatment selection will depend on 46 whether the pain occurs at rest and with all motion or if it occurs in response to active or passive motion only. When motion is restricted by pain that is present at rest and with all motion, the first treatment goal is to reduce pain severity. This can be achieved, as previously described, with the use of ES, cryotherapy, thermotherapy, or SWT. If pain and motion restriction are related to compressive spinal dysfunction, spinal traction may be used to alleviate pain and promote increased motion. When pain restricts motion with active motion only, this indicates an injury of contractile tissue, such as muscle or tendon, without complete rupture.44 When both active motion and passive motion are restricted by pain, noncontractile tissue, such as ligament or meniscus, is involved. Physical agents may help restore motion after an injury to contractile or noncontractile tissue by promoting tissue healing or by controlling pain, which has already been described. When active motion and passive motion are restricted by soft tissue shortening or by a bony block, the restriction generally is not accompanied by pain. Soft tissue shortening may be reversed by stretching, and thermal agents may be used before or in conjunction with stretching to increase soft tissue extensibility, thus promoting a safer, more effective stretch.45 The ideal thermal agent depends on the depth, size, and contouring of the tissue to be treated. Deep-heating agents, such as ultrasound or diathermy, should be used when motion is restricted by shortening of deep tissues such as the shoulder joint capsule, whereas superficial heating agents, such as hot packs, paraffin, warm whirlpools, or IR lamps, should be used when motion is restricted by shortening of superficial tissues such as the skin or subcutaneous fascia. Ultrasound should be used to treat small areas of deep tissue, whereas diathermy is more appropriate for larger areas. Hot packs can be used to treat large or small areas of superficial tissue with little or moderate contouring. Paraffin or a whirlpool is more appropriate to treat small areas with greater contouring. IR lamps can be used to heat large or small areas, but they provide consistent heating only to relatively flat surfaces. Because increasing tissue extensibility alone will not decrease soft tissue shortening, thermal agents must be used in conjunction with stretching techniques to increase soft tissue length and reverse motion restrictions caused by soft tissue shortening. Brief forms 47 of cryotherapy, such as brief ice massage or vapocoolant sprays, may be used before stretching to facilitate greater increases in muscle length by reducing the discomfort of stretching; however, prolonged cryotherapy should not be used before stretching because cooling soft tissue decreases its extensibility.46,47 When a bony block restricts motion, the goal of intervention is to remove the block or to compensate for loss of motion. Physical agents cannot remove a bony block, but they may help with compensation for loss of motion by facilitating increased motion at other joints. Motion may be increased at other joints by the judicious use of thermotherapy or brief cryotherapy with stretching. Such treatment should be applied with caution to avoid injury, hypermobility, and other types of dysfunction in previously normal joints. Applying a stretching force to a joint that is blocked by a bony obstruction is not recommended because this force will not increase ROM at that joint and may cause inflammation by traumatizing intraarticular structures. Muscle Tone Muscle tone is the underlying tension that serves as background for contraction of a muscle. Muscle tone is affected by neural and biomechanical factors and can vary in response to pathology, expected demand, pain, and position. Abnormal muscle tone is usually the direct result of nerve pathology or may be a secondary sequela of pain that results from injury to other tissues. Central nervous system injury, as may occur with head trauma or stroke, can result in increased or decreased muscle tone in the affected area, whereas peripheral motor nerve injury, as may occur with nerve compression, traction, or sectioning, can decrease muscle tone in the affected area. For example, a patient who has had a stroke may have increased tone in the flexor muscles of the upper extremity and the extensor muscles of the lower extremity on the same side, whereas a patient who has had a compression injury to the radial nerve as it passes through the radial groove in the arm may have decreased tone in the wrist and finger extensors. Pain may increase or decrease muscle tone. Muscle tone may increase in the muscles surrounding a painful injured area to splint the area and 48 limit motion, or tone in a painful area may decrease as a result of inhibition. Although protective splinting may prevent further injury from excessive activity, it can impair circulation if prolonged, thus retarding or preventing healing. Decreased muscle tone as a result of pain—as occurs, for example, with reflexive hypotonicity (decreased muscle tone) of the knee extensors that causes buckling of the knee when knee extension is painful—can limit activity. Physical agents can alter muscle tone directly by altering nerve conduction, nerve sensitivity, or biomechanical properties of muscle or indirectly by reducing pain or the underlying cause of pain. Normalizing muscle tone generally reduces functional limitations and disability, allowing the individual to improve performance of functional and therapeutic activities. Attempting to normalize muscle tone may promote better outcomes from passive treatment techniques such as passive mobilization or positioning. Processes underlying changes in muscle tone are discussed fully in Chapter 5. Clinical Pearl Physical agents can alter muscle tone directly by altering nerve conduction, nerve sensitivity, or biomechanical properties of muscle or indirectly by reducing pain or the underlying cause of pain. Physical Agents for Tone Abnormalities Physical agents can temporarily modify muscle hypertonicity, hypotonicity, or fluctuating tone (Table 1.5). Hypertonicity may be reduced directly by the application of neutral warmth or prolonged cryotherapy to hypertonic muscles, or it may be reduced indirectly by stimulating an antagonist muscle contraction with motor-level ES or quick icing. Stimulating antagonist muscles indirectly reduces hypertonicity because activity in these muscles causes reflex relaxation and reduces tone in opposing muscles. In the past, stimulation of hypertonic muscles with motor-level ES or quick icing generally was not recommended because of concern that this would further increase muscle tone; however, reports indicate that ES of hypertonic muscles improves patient function, likely by increasing strength and voluntary 49 control of these muscles.48,49 TABLE 1.5 Physical Agents for the Treatment of Tone Abnormalities Tone Goals of Contraindicated Effective Agents Abnormality Treatment Agents Hypertonicity Decrease tone Neutral warmth, prolonged cryotherapy, or EMG Quick ice of biofeedback to hypertonic muscles agonists Motor ES or quick ice of antagonists Hypotonicity Increase tone Quick ice, motor ES, or EMG biofeedback to agonists Thermotherapy Fluctuating Normalize Functional ES tone tone EMG, Electromyographic; ES, electrical stimulation. In patients with muscle hypotonicity, in which the goal of intervention is to increase tone, quick icing or motor-level ES of hypotonic muscles may be beneficial. In contrast, applying heat to these muscles should usually be avoided because this may further reduce muscle tone. In patients with fluctuating tone, for whom the goal of treatment is to normalize tone, functional ES may be applied to cause a muscle or muscles to contract at the appropriate time during functional activities. For example, if a patient cannot maintain a functional grasp because they cannot contract the wrist extensors while contracting the finger flexors, ES can induce the wrist extensors to contract at the appropriate time during active grasping. 50 General Contraindications and Precautions for Physical Agent Use Restrictions on the use of particular treatment interventions are categorized as contraindications or precautions. Contraindications are conditions under which a particular treatment should not be applied, and precautions are conditions under which a particular form of treatment should be applied with special care or limitations. The terms absolute contraindications and relative contraindications can be used in place of contraindications and precautions, respectively. Although contraindications and precautions for the application of specific physical agents vary, several conditions are contraindications or precautions for the use of most physical agents. Therefore caution should be used when applying a physical agent to a patient having any of these conditions. In patients with such conditions, the nature of the restriction, the nature and distribution of the physiological effects of the physical agent, and the distribution of energy produced by the physical agent must be considered. Contraindications for Application of a Physical Agent Pregnancy Malignancy Pacemaker or other implanted electronic device Impaired sensation Impaired mentation Pregnancy 51 Pregnancy is generally a contraindication or precaution for the application of a physical agent if the energy produced by that agent or its physiological effects may reach the fetus. These restrictions apply because the influences of these types of energy on fetal development usually are unknown and because fetal development is adversely affected by many influences, some of which are subtle. Malignancy Malignancy is a contraindication or precaution for the application of physical agents if the energy produced by the agent or its physiological effects may reach malignant tissue or alter the circulation to such tissue. Some physical agents are known to accelerate the growth, or metastasis, of malignant tissue. These effects are thought to result from increased circulation or altered cellular function. Care must be taken when considering treatment on any area of the body that currently has or previously had cancer cells because malignant tissue can metastasize and therefore may be present in areas where it has not yet been detected. Pacemaker or Other Implanted Electronic Device The use of a physical agent is generally contraindicated when the energy of the agent can reach a pacemaker or any other implanted electronic device (e.g., deep brain stimulator, spinal cord stimulator, implanted cardioverter defibrillator) because the energy produced by some of these agents may alter the functioning of the device. Impaired Sensation and Mentation Impaired sensation and mentation are contraindications or precautions for the use of many physical agents because the limit for application of these agents is the patient's report of how they feel. For example, for most thermal agents, the patient's report of the sensation of heat as comfortable or painful is used to guide the intensity of treatment. If the patient cannot feel heat or pain because of impaired sensation or cannot report this sensation accurately and consistently because of impaired mentation or other factors affecting their ability to communicate, 52 applying the treatment is not safe and therefore is contraindicated. Although these conditions indicate the need for caution with the use of most physical agents, the specific contraindications and precautions for the agent being considered and the patient's situation must be evaluated before an intervention may be used or should be rejected. For example, although applying ultrasound to a pregnant patient is contraindicated in any area where the ultrasound may reach the fetus, this physical agent may be applied to the distal extremities of a pregnant patient because ultrasound penetration is shallow and limited to the area close to the applicator. In contrast, it is recommended that diathermy not be applied to any part of a pregnant patient because the electromagnetic radiation it produces reaches areas distant from the applicator. Specific contraindications and precautions, including questions to ask the patient and features to assess before the application of each physical agent, are provided in Part II of this book. 53 Evaluation and Planning for the Use of Physical Agents Physical agents have direct effects primarily at the level of impairment. These effects can improve activity and participation. For example, for a patient with pain that impairs motion, electrical currents can be used to stimulate sensory nerves to control pain and allow the patient to increase motion and thus increase activity, such as lifting objects, and participation, such as returning to work. Physical agents can also increase the effectiveness of other interventions and should generally be used to facilitate an active treatment program.50 For example, a hot pack may be applied before stretching to increase the extensibility of superficial soft tissues and promote a safer and more effective increase in soft tissue length when the patient stretches. When considering the application of a physical agent, one should first check the physician's referral, if one is required, for a medical diagnosis of the patient's condition and any necessary precautions. Precautions are conditions under which a particular treatment should be applied with special care or limitations. The therapist's examination should include, but should not be limited to, the patient's history, which would include information about the history of the current complaint, relevant medical history, and information about current and expected levels of activity and participation; a review of systems; and specific tests and measures. Examination findings and a survey of available evidence in the published literature should be considered in tandem to establish a prognosis and select the interventions and a plan of care, including anticipated goals. This plan may be modified as indicated through ongoing reexamination and reevaluation. The process of staying abreast of the latest clinical evidence is discussed in more detail in Chapter 2, and the sequence of examination, evaluation, and intervention follows in the case studies described in Part II of this book. Choosing a Physical Agent Physical agents generally assist in rehabilitation by reducing 54 inflammation, pain, and motion restrictions; healing tissue; and improving muscle tone. Guidelines for selecting appropriate interventions based on the direct effects of physical agents are presented here in narrative form and are summarized in Tables 1.2 through 1.5. If the patient presents with more than one problem and so has numerous goals for treatment, only a limited number of goals should be addressed at any one time. It is generally recommended that the primary problems and problems most likely to respond to available interventions should be addressed first; however, the ideal intervention will facilitate progress in a number of areas (Fig. 1.2). For example, if a patient has knee pain caused by acute joint inflammation, treatment should first be directed at resolving the inflammation; however, the ideal intervention would also help to relieve pain. When the primary underlying problem, such as arthritis, cannot benefit directly from intervention with a physical agent, treatment with physical agents may still be used to help alleviate sequelae of these problems, such as pain or swelling. FIGURE 1.2 Prioritizing goals and effects of treatment. 55 Attributes to Consider in the Selection of Physical Agents Given the variety of available physical agents and the unique characteristics of each patient, it is helpful to take a systematic approach to selecting the physical agents so that the ideal agent will be applied in each situation (Fig. 1.3). FIGURE 1.3 Attributes to be considered in the selection of physical agents. Clinical Pearl Because of the variety of available physical agents and the unique characteristics of each patient, it is important to take a systematic selection approach so that the ideal agent will be applied in each situation. The first consideration should be the goals of the intervention and the physiological effects required to reach these goals. If the patient has inflammation, pain, motion restrictions, or problems with muscle tone, using a physical agent may be appropriate. Looking at the effects of a particular physical agent on these conditions is the next step. Having determined which physical agents can promote progress toward 56 determined goals, the clinician should then decide which of the potentially effective interventions would be most appropriate for the particular patient and their current clinical presentation. In keeping with the rule of “Do no harm,” all contraindicated interventions should be rejected and all precautions adhered to. If several methods would be effective and could be applied safely, evidence related to these interventions, ease and cost of application, and availability of resources should also be considered. After selecting physical agents, the clinician must select the ideal treatment parameters and means of application and then must appropriately integrate the chosen agents into a complete rehabilitation program. Because physical agents have differing levels of associated risk when all other factors are equal, agents with a lower level of risk should be selected. Physical agents with a low level of associated risk have a potentially harmful dose that is difficult to achieve or is much greater than the effective therapeutic dose and thus have contraindications that are easy to detect. In contrast, physical agents with a high level of associated risk have an effective therapeutic dose that is close to the potentially harmful dose and have contraindications that are more difficult to detect. For example, hot packs that are heated in hot water and are used with sufficient insulation have a low associated risk: although they can heat superficial tissues to a therapeutic level in 15 to 20 minutes, they are unlikely to cause a burn if applied for a longer period because they start to cool as soon as they are removed from the hot water. In contrast, UV radiation has a high associated risk: a slight increase in treatment duration, for example, changing the duration from 5 to 10 minutes or using the same treatment duration for patients with different skin sensitivities, may change the treatment's effect from a therapeutic outcome to a severe burn. Diathermy also has a high associated risk because it preferentially heats metal, which may have been previously undetected, and can burn tissue that is near any metal objects in the treatment field. It is generally recommended that agents with higher associated risk should be used only if agents with lower risk would not be as effective and that special care should be taken to minimize risks when these agents are used. 57 Using Physical Agents in Combination With Each Other or With Other Interventions To progress toward the goals of intervention, a number of physical agents may be used simultaneously and sequentially, and physical agents are often applied in conjunction with or during the same treatment session as other interventions. Interventions are generally combined when they have similar effects or when they address different aspects of a common array of symptoms. For example, splinting, ice, pulsed ultrasound, laser light, SWT, and phonophoresis or iontophoresis may be used during the acute inflammatory phase of healing. Splinting can limit further injury; ice may control pain and limit circulation; pulsed ultrasound, laser light, and SWT may promote progress toward the proliferation stage of healing; and phonophoresis and iontophoresis may limit the inflammatory response. During the proliferation stage of healing, heat, motor-level ES, and exercise may be used, and ice or other inflammation-controlling interventions may continue to be applied after activity to reduce the risk of recurring inflammation. Rest, ice, compression, and elevation (RICE) are frequently combined for the treatment of inflammation and edema because these interventions can control inflammation and edema. Rest limits and prevents further injury, ice reduces circulation and inflammation, compression elevates hydrostatic pressure outside the blood vessels, and elevation reduces hydrostatic pressure within the blood vessels of the elevated area to decrease capillary filtration pressure at the arterial end and facilitate venous and lymphatic outflow from the limb.51-54 ES may be added to this combination to further control inflammation and the formation of edema by repelling negatively charged blood cells and ions associated with inflammation. When the goal of intervention is to control pain, a number of physical agents may be used to influence different mechanisms of pain control. For example, cryotherapy or thermotherapy may be used to modulate pain transmission at the spinal cord, whereas motor-level ES may be used to modulate pain by stimulating endorphin release. These physical agents may be combined with other pain-controlling interventions such as medications and may be used in conjunction with treatments such as 58 joint mobilization and dynamic stabilization exercise, which are intended to address the underlying impairment causing pain. When the goal of intervention is to alter muscle tone, various tone- modifying physical agents or other interventions may be applied during or before activity to promote more normal movement and to increase the efficacy of other aspects of treatment. For example, ice may be applied for 30 to 40 minutes to the leg of a patient with hypertonicity of the ankle plantar flexors caused by a stroke to temporarily control the hypertonicity of these muscles, thereby promoting a more normal gait pattern during gait training. Because practicing normal movement is thought to facilitate the recovery of more normal movement patterns, such treatment may promote a superior outcome. When the goal of intervention is to reverse soft tissue shortening, application of thermal agents before or during stretching or mobilization is recommended to promote relaxation and increase soft tissue extensibility, thereby increasing the efficacy and safety of treatment. For example, hot packs are often applied in conjunction with mechanical traction to help relax the paraspinal muscles and to increase the extensibility of superficial soft tissues in the area to which traction is being applied. Physical agents are generally used more extensively during the initial rehabilitation sessions when inflammation and pain control are matters of priority, with progression over time to more active or aggressive interventions, such as exercise or passive mobilization. Progression from one physical agent to another or from the use of a physical agent to another intervention should be based on the course of the patient's problem. For example, hydrotherapy may be applied to cleanse and debride an open wound during initial treatment sessions; however, once the wound is clean, this treatment should be stopped, and ES may be initiated to promote collagen deposition. 59 Documentation Documentation involves entering information into a patient's medical record, whether handwritten, dictated, or typed into a computer. Purposes of documentation include communicating examination findings, evaluations, interventions, and plans to other health care professionals; serving as a long-term record; and supporting reimbursement for services provided. Clinical Pearl Good documentation effectively, accurately, and completely communicates examination findings, evaluations, interventions, and plans to other health care professionals; serves as a long-term record; and supports reimbursement for services provided. Documentation of a patient encounter may follow any format but is often done in the traditional SOAP note format to include the four sequential components of subjective (S), objective (O), assessment (A), and plan (P). Alternative documentation schemes may be used in various electronic medical records. The SOAP note format is used in this book for consistency and to demonstrate the reasoning used. Within each component of the SOAP note, details vary depending on the patient's condition and assessment and the interventions applied. In general, when use of a physical agent is documented, information on the agent used should be included, as should details on the area of the body treated; intervention duration, parameters, and outcomes, including progress toward goals; and regressions or complications arising from application of the physical agent. An example of a SOAP note written after a hot pack was applied to the lower back follows. S: Pt reports low back pain and decreased sitting tolerance, which functionally prohibit writing. O: Pretreatment: Pain level 7/10. Forward and side-bending ROM restricted 50% by pain and muscle spasm. Pt unable to lean forward 60 for writing tasks. Intervention: Hot pack to low back, 20 minutes, Pt prone, six layers of towels. Pt performed single knee to chest 2 × 10, double knee to chest 2 × 10. Posttreatment: Pain level 4/10. Forward-bending increased, restricted 20%. Pt instructed in home exercise program of SKTC and DKTC 3 × 10 daily. A: Pain decreased, forward bending ROM. P: Continue use of hot pack as above before stretching. Progress exercise program. Specific recommendations for SOAP note documentation and examples are given in chapters for all physical agents discussed in this book. 61 Chapter Review 1. Physical agents consist of materials or energy applied to patients to assist in rehabilitation. Physical agents include heat, cold, water, pressure, sound, electromagnetic radiation, and electrical currents. These agents can be categorized as thermal (e.g., hot packs, cold packs), mechanical (e.g., compression, traction), or electromagnetic (e.g., lasers, ES, UV radiation, EMG biofeedback). Some physical agents fall into more than one category. For example, water and ultrasound are both thermal and mechanical agents. 2. Physical agents are components of a complete rehabilitation program. They should not be used as the sole intervention for a patient. 3. Physical agents are commonly used in conjunction with each other and with other interventions. 4. Selection of a physical agent is based on integrating findings from the patient examination with evidence of the effects (both positive and negative) of available agents. 5. Physical agents primarily affect inflammation and healing, pain, motion restrictions, and tone abnormalities. Knowledge of normal and abnormal physiology in each area can help in selection of a physical agent for a patient. These are discussed in Chapters 3 through 6. The specific effects of particular physical agents are discussed in Chapters 7 through 20. 6. Contraindications are circumstances in which a physical agent should not be used. Precautions are circumstances in which a physical agent should be used with caution. General contraindications and precautions, such as pregnancy, malignancy, pacemaker, and impaired sensation and mentation, pertain to the application of all physical agents. Specific contraindications and precautions for each physical agent are discussed in Chapters 7 through 20. 62 Glossary Collagen: A glycoprotein that provides the extracellular framework for all multicellular organisms. Complex regional pain syndrome (CRPS): Pain believed to involve sympathetic nervous system overactivation; previously called reflex sympathetic dystrophy and sympathetically maintained pain. Compression: The application of a mechanical force that increases external pressure on a body part to reduce swelling, improve circulation, or modify scar tissue formation. Contraindications: Conditions in which a particular treatment should not be applied; also called absolute contraindications. Contrast bath: Alternating immersion in hot and cold water. Cryotherapy: The therapeutic use of cold. Diathermy: The application of shortwave or microwave electromagnetic energy to produce heat within tissues, particularly deep tissues. Electrical stimulation (ES): The use of electrical current to induce muscle contraction (motor level) or changes in sensation (sensory level). Electromagnetic agents: Physical agents that apply energy to the patient in the form of electromagnetic radiation or electrical current. Fluidotherapy: A dry heating agent that transfers heat by convection. It consists of a cabinet containing finely ground particles of cellulose through which heated air is circulated. Guide to Physical Therapist Practice 3.0 (Guide 3.0): A book used by physical therapists to categorize patients according to preferred 63 practice patterns that include typical findings and descriptive norms of types and ranges of interventions for patients in each pattern. Hydrotherapy: The therapeutic use of water. Hypotonicity: Low muscle tone or decreased resistance to stretch compared with normal muscles. Indications: Conditions under which a particular treatment should be applied. Inflammation: The body's first response to tissue damage, characterized by heat, redness, swelling, pain, and often loss of function. Inflammatory phase: The first phase of healing after tissue damage. Infrared (IR) radiation: Electromagnetic radiation in the IR range (wavelength range, approximately 750 to 1300 nm) that can be absorbed by matter and, if of sufficient intensity, can cause an increase in temperature. Iontophoresis: The transcutaneous delivery of ions into the body for therapeutic purposes using an electrical current. Laser: LASER is the acronym for light amplification by stimulated emission of radiation; laser light is monochromatic, coherent, and directional. Maturation phase: The final phase of healing after tissue damage. During this phase, scar tissue is modified into its mature form. Mechanical agents: Physical agents that apply force to increase or decrease pressure on the body. Modality, physical modality: Other terms for physical agent. Muscle tone: The underlying tension in a muscle that serves as a background for contraction. 64 Nonthermal shortwave therapy (SWT): The therapeutic use of intermittent shortwave radiation in which heat is not the mechanism of action (previously called pulsed shortwave diathermy [PSWD]). Pain: An unpleasant sensory and emotional experience associated with actual or threatened tissue damage. Paraffin: A waxy substance that can be warmed and used to coat the extremities for thermotherapy. Pathology: Alteration of anatomy or physiology as a result of disease or injury. Phonophoresis: The application of ultrasound with a topical drug to facilitate transdermal drug delivery. Physical agents: Energy and materials applied to patients to assist in rehabilitation. Precautions: Conditions in which a particular treatment should be applied with special care or limitations; also called relative contraindications. Proliferation phase: The second phase of healing after tissue damage, in which damaged structures are rebuilt and the wound is strengthened. Pulsed ultrasound: Intermittent delivery of ultrasound during the treatment period. Rehabilitation: Goal-oriented intervention designed to maximize independence in individuals who have compromised function. Thermal agents: Physical agents that increase or decrease tissue temperature. Thermotherapy: The therapeutic application of heat. Traction: The application of a mechanical force to the body in a way that 65 separates, or attempts to separate, the joint surfaces and elongates surrounding soft tissues. Ultrasound: Sound with a frequency greater than 20,000 cycles per second (Hz) that is used as a physical agent to produce thermal and nonthermal effects. Ultraviolet (UV) radiation: Electromagnetic radiation in the ultraviolet range (wavelength < 290 to 400 nm) that lies between x-ray and visible light and has nonthermal effects when absorbed through the skin. 66 References 1. APTA. Guide to physical therapist practice 3.0. [Alexandria, VA; American Physical Therapy Association] http://guidetoptpractice.apta.org/; 2014 [(Accessed 23 May 2016)]. 2. World Health Organization (WHO). Towards a common language for functioning, disability and health: International Classification of Functioning, Disability and Health (ICF). [Geneva] 2002 [WHO]. 3. Weston M, Taber C, Casgranda L, et al. Changes in local blood volume during cold gel pack application to traumatized ankles. J Orthop Sports Phys Ther. 1994;19:197–199. 4. Wolf SL. Contralateral upper extremity cooling from a specific cold stimulus. Phys Ther. 1971;51:158–165. 5. Bickford RH, Duff RS. Influence of ultrasonic irradiation on temperature and blood flow in human skeletal muscle. Circ Res. 1953;1:534–538. 6. Fox HH, Hilton SM. Bradykinin formation in human skin as a factor in heat vasodilation. J Physiol. 1958;142:219. 7. Schmidt KL. Heat, cold, and inflammation. Rheumatology. 1979;38:391–404. 8. Moore Z, Cowman S. A systematic review of wound cleansing for pressure ulcers. J Clin Nurs. 2008;17:1963–1972. 9. Fernandez R, Griffiths R. Water for wound cleansing. Cochrane Database Syst Rev. 2012;(2) [CD003861]. 10. Leeder J, Gissane C, van Someren K, et al. Cold water immersion and recovery from strenuous exercise: a meta-analysis. Br J Sports Med. 2012;46:233–240. 11. Benson TB, Copp EP. The effects of therapeutic forms of heat and ice on the pain threshold of the normal shoulder. Rheumatol Rehabil. 1974;13:101–104. 12. Vance CG, Dailey DL, Rakel BA, et al. Using TENS for pain control: the state of the evidence. Pain Manag. 2014;4:197–209. 13. Teslim OA, Adebowale AC, Ojoawo AO, et al. Comparative effects of pulsed and continuous short wave diathermy on pain 67 and selected physiological parameters among subjects with chronic knee osteoarthritis. Technol Health Care. 2013;21:433–440. 14. Cote DJ, Prentice WE, Hooker DN, et al. Comparison of three treatment procedures for minimizing ankle sprain swelling. Phys Ther. 1988;68:1072–1076. 15. Wilkerson GB. Treatment of inversion ankle sprain through synchronous application of focal compression and cold. J Athl Train. 1991;26:220–237. 16. Quillen WS, Roullier LH. Initial management of acute ankle sprains with rapid pulsed pneumatic compression and cold. J Orthop Sports Phys Ther. 1982;4:39–43. 17. Gupta A, Keshri GK, Yadav A, et al. Superpulsed (Ga-As, 904 nm) low-level laser therapy (LLLT) attenuates inflammatory response and enhances healing of burn wounds. J Biophotonics. 2015;8:489–501. 18. Bohari SP, Grover LM, Hukins DW. Pulsed low-intensity ultrasound increases proliferation and extracellular matrix production by human dermal fibroblasts in three-dimensional culture. J Tissue Eng. 2015;6. 19. Lentell G, Hetherington T, Eagan J, et al. The use of thermal agents to influence the effectiveness of low-load prolonged stretch. J Orthop Sports Phys Ther. 1992;16:200–207. 20. Lin Y. Effects of thermal therapy in improving the passive range of knee motion: comparison of cold and superficial heat applications. Clin Rehabil. 2003;17:618–623. 21. Atkins TJ, Duck FA. Heating caused by selected pulsed Doppler and physiotherapy ultrasound beams measured using thermal test objects. Eur J Ultrasound. 2003;16:243–252. 22. Draper DO, Castel JC, Castel D. Rate of temperature increase in human muscle during 1 MHz and 3 MHz continuous ultrasound. J Orthop Sports Phys Ther. 1995;22:142–150. 23. Draper DO, Hawkes AR, Johnson AW, et al. Muscle heating with Megapulse II shortwave diathermy and ReBound diathermy. J Athl Train. 2013;48:477–482. 24. Mitchell SM, Trowbridge CA, Fincher AL, et al. Effect of diathermy on muscle temperature, electromyography, and 68 mechanomyography. Muscle Nerve. 2008;38:992–1004. 25. Minson CT, Berry LT, Joyner MJ. Nitric oxide and neurally mediated regulation of skin blood flow during local heating. J Appl Physiol. 2001;91:1619–1626. 26. Broderick BJ, O'Connell S, Moloney S, et al. Comparative lower limb hemodynamics using neuromuscular electrical stimulation (NMES) versus intermittent pneumatic compression (IPC). Physiol Meas. 2014;35:1849–1859. 27. Chen AH, Frangos SG, Kilaru S, et al. Intermittent pneumatic compression devices—physiological mechanisms of action. Eur J Vasc Endovasc Surg. 2001;21:383–392. 28. Breger St

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