"The Regeneration Process of Tissues Through Various Modalities."
       

    Toni B. Workman
    Biology Senior Seminar 410
    Stan Grove
    November 29, 1999

     

    Thesis:  When an injury is sustained, the body sets into motion various processes, which are needed to repair the damaged tissue. A Physical Therapist or Athletic Trainer can aid the natural repair processes of tissue by using various therapeutic modalities within an appropriate time shortly after an injury. This paper will discuss the physiological effects of therapeutic modalities and their relation to the regeneration process of tissues.



       I. Introduction
    A.  The injury process
    B.  The use/role of therapeutic modalities

    II. The Anatomical Characteristics of Muscle

    III. Types of Therapeutic Modalities
           A.  Ice packs
              -Physiological effects
              -Process of tissue regeneration

           B.  Heat packs
              -Physiological effects
              -Process of tissue regeneration

           C.  Ultrasound
              -Physiological effects
              -Process of tissue regeneration

           D.  Neuromuscular Electric Stimulation
             -Physiological effects
              -Process of tissue regeneration

    IV. Usage of Physical Therapy and Athletic Training
           A.  Why is therapy needed for the proper healing of muscle tissue?

           B. Advantages
             -Proper tissue regeneration
             -Full recovery after an injury

           C. Disadvantages
              -Weak Tendons and Ligaments (no proper tissue regeneration)
              -Surgical Intervention

           D. Controversial Issues Surrounding Athletic Training and Physical Therapy

    V.Conclusion
       


    A. The injury process
    The body's reaction to injury may be divided into two distinct parts. The primary response to injury is the tissue destruction directly associated with the traumatic force. Secondary damage occurs from cell death caused by a blockage of the oxygen supply to the injured area. The damage done during the primary stage is irreversible, and the treatment efforts used after trauma attempt to contain the effects and limit the amount of secondary injury. Dead and damaged cells release their contents into the area adjacent to the injured site. The presence of these substances causes an inflammatory reaction from the body's tissues. As a result of both the primary trauma and the inflammatory mediators, hemorrhage and edema occur (Starkey, 10).

    B.The use/role of therapeutic modalities
    A modality is the application of some form of stress to the body for the purpose of eliciting an adaptive response. The term "therapeutic" is essential to fully describe the principles behind the application of thermal, mechanical, electrical, or chemical energy to the body. To be deemed therapeutic, the stress applied to the body must be conducive to the healing process of the injury in its current state. The optimum conditions for healing require a balance between protecting the area from further distresses and returning the body segment to normal function at the earliest possible time. Hence, the application of a modality at an improper point in its recovery phase may hinder, if not actually set back, the healing process (Starkey, 30).


    Therapeutic modalities are used to control and limit the negative effects of inflammation by providing the optimum environment for healing to occur. Each         modality used in the treatment of an injury should be judged for the effect it will have on the injury response process in the current stage of healing (Starkey, 31). The course of healing is described in three phases: (1) the acute inflammatory response, (2) the proliferation phase, and (3) the remodeling (maturation) phase
(Starkey, 12).

    The acute inflammatory response involves the delivery of phagocytes, specifically fibroblasts, to the area and the formation of granulation tissue in an attempt to isolate and localize the trauma. During this time, histamine released from the traumatized cells increases capillary permeability, resulting in swelling as the proteins follow water out into the tissues (Starkey, 13).

    During the proliferation phase, in which soft tissue repair occurs, the number and size of fibroblasts increase, causing ground substance and collagen to collect in the traumatized area in preparation to rebuild the damaged tissues. The injury process is completed during the maturation phase, when collagen and fibroblasts align themselves and attempt to adapt to the original tissue orientation and function, although this does not always occur (Starkey, 13).

    Reparation of an injured structure involves the interaction between two types of cells, which are the cells belonging to the injured structure, and connective tissue. Inflammation is needed for tissue repair. However, too much inflammation is detrimental to the process. Athletic trainers and physical therapists attempt to regulate the inflammatory process through the application of therapeutic modalities, the use of immobilization devices, exercise, the administrative of anti-inflammatory medication, and so on (Starkey, 26).

    Regeneration of tissues occurs when the new cells are of the same type and can perform the same function as the original structure. The quality of the repair process is related to the number and type of cells that have been damaged (Starkey, 26). Adenosine Triphosphate (ATP) is a critical factor that regulates the rate and quality of healing. Serving as the cell's primary source of energy, ATP is required to provide the metabolism needed to restore the cell's membrane properties. This is done by moving sodium and potassium into and out of the cell, which builds and synthesizes new proteins (Starkey, 27.)

II. The Anatomical Characteristics of Muscle

    Muscles are composed of contractile cells, or fibers, that produce movement. Muscle fibers have the ability to contract, plus the properties of irritability, conductivity, and elasticity. Three types of muscle are within the body-smooth, cardiac and striated. In sports medicine conditions, the striated or skeletal muscle is of major concern.

    Within the fiber cell is a semifluid substance called sarcoplasm or cytoplasm. Myofibrils are surrounded by the endomysium, fiber bundles are surrounded by the perimysium, and the entire muscle is covered by the epimysium. The epimysium, perimysium, and endomysium may be combined with the fibrous tendon. The fibrous wrapping of a muscle may become a flat sheet of connective tissue (aponeurosis) that attaches to other muscles (Arnheim & Prentice, 152).

    The essential characteristic that distinguishes connective tissue from the other three tissue types is that it consists of cells separated from each other by abundant extacellular matrix. The specialized cells of the various connective tissues produce the extracellular matrix. The names of the cells end with suffixes that identify the cell functions as blasts, cytes, of clasts. Blasts create the matrix, cytes maintain it, and clasts break it down for remodeling. The extracellular matrix has three major components: (1) protein fibers, (2) ground substance consisting of nonfibrous protein and other molecules, and (3) fluid. The structure of the matrix gives connective tissue types most of their functional characteristics. Some of these are the ability of bones and cartilage to bear weight, of tendons and ligaments to withstand punctures, abrasions, and other abuses(Seeley, Stephans and Tate, 111).

    Skeletal muscle contracts in response to electric signals, called action potentials, that are conducted along the axon of nerve cells to the synapses between the axons and muscle fibers. Nerve cells regulate the function of skeletal muscle fibers by controlling the frequency of action potentials produced in the muscle cell membrane. Action potentials in skeletal muscle fibers trigger a series of chemical events that result in muscle contraction (Seeley, Stephans, and Tate, 277).

II. Types of Therapeutic Modalities
A. Ice packs

    Cryotherapy is an umbrella term covering a number of specific techniques. The term cryotherapy literally means "cold therapy". Cryotherapy is the therapeutic application of any substance to the body which results in the withdrawal of heat from the body, thereby lowering tissue temperature (Knight, 7). Cryotherapy techniques, when used properly, provide the clinician with some very powerful tools for managing musculoskeletal pathology, both during the initial care phase of acute trauma and during rehabilitation of assorted musculoskeletal pathologies (Knight, 2). The proponents of cold therapy report that cold provides a number of physiological effects. It produces anesthesia, decreases pain and muscle spasm, increases relaxation and range of motion (R.O.M), allows for earlier immobilization, decreases metabolism and inflammation and increases tissue stiffness (Knight, 45).

    Several factors affect the degree of superficial and deep tissue temperature change accomplished by cryotherapy. These factors include tissue type, depth of the target tissue, temperature gradient between the target tissue and the cooling agent, size of the area being treated, and length of the application (Myrer, 25). Included in the techniques of cryotherapy is the usage of Ice packs. Ice pack applications are used for the immediate care of acute injuries. It is also used for tissue cooling during rehabilitation of various musculoskeletal pathologies as an adjunct to other therapy (Knight, 7). The primary benefit of cold during rehabilitation is that it decreases pain and allows for earlier mobilization. Not only does the proper use of exercise speed up the healing process, but lack the exercise during the early stages of rehabilitation may result in permanent disability (Knight, 9). Many authorities claim that cold applications decrease blood flow, thereby diminishing the amount of hemorrhage into the traumatized tissue. Using ice during the immediate care phase decreases recovery time in at least three ways. The first is by decreasing secondary hypoxic injury there is less total damage and thus less to be repaired. The second is that with less damage there is less tissue debris and so the hematoma can be resolved quicker. Since hematoma is a necessary prerequisite to repair the smaller the hematoma, the quicker repair can begin. Because of the effect of ice decreasing secondary hypoxic injury, repair both begins quicker and is shorter in duration. The third is by decreasing pain and muscle spasm, there is less inhibition of normal range of motion and muscular strength. Thus the athlete can become active much quicker, which in turn decreases many of the other complications of injury (Knight, 17-18).

B. Heat packs

    Heat is the increase in molecular vibration and cellular metabolic rate. The application of therapeutic heat to the body is referred to as thermotherapy, and the methods of heating are classified as being superficial to deep. Superficial heating agents must be capable of increasing the skin temperature within the range of 104° F to 113° F to produce therapeutic effects. The transfer of heat to underlying tissues occurs via conduction (Starkey, 121). Conduction involves the transfer of heat between two objects that are in physical contact with each other. This is how the transfer of energy from one tissue layer to another occurs in the body (Starkey, 122).

    Both heat and cold applications decrease pain and muscle spasm by altering the threshold of nerve endings. Systematically local heat applications result in increased body temperature, pulse rate, and respiratory rate and decreased blood pressure. The use of heat is indicated in the subacute and chronic inflammatory stages of injury (Starkey, 121). There is a reciprocal relationship between tissue temperature and the rate of cell metabolism. Not only does increased temperature cause an increase in cellular metabolic rate, but an increase in cellular metabolic rate also causes tissue temperature to rise. As with all heat applications increased cellular metabolic cause arteriolar dilation and increased capillary flow. This supports the therapeutic properties of exercise. Despite the fact that heat and cold produce many of the same outcomes, decreased pain for example, the timing of when to begin using heat modalities is much more critical. A primary effect of heat modalities is an increase in cell metabolism and the rate of inflammation. For each increase of 18° F in skin temperature, the cell's metabolic rate increases by a factor of two or three (Starkey, 124).

C. Ultrasound

    Ultrasound is a deep penetrating modality capable of producing changes in tissue through thermal and nonthermal (mechanical) mechanisms (Starkey, 269). The nonthermal effects of ultrasound increase cellular diffusion and membrane permeability, as well as fibroblastic activities, such as protein synthesis, that speed up tissue regeneration. The thermal effects of ultrasound are desired in treating chronic soft tissue injuries that result in inflammation(Chan, 130). Therapeutic ultrasound is frequently employed as a deep heating rehabilitation modality. It is administered in one of three ways: (1) ultrasound with no preceding treatment, (2) ultrasound on preheated tissues, or (3) ultrasound on precooled tissues ( 2Draper, 325). Unlike most other electrically driven modalities, ultrasonic energy is not a part of the electromagnetic spectrum but is located on the acoustical spectrum. Depending on the frequency of the waves, ultrasound is used for diagnostic imaging, therapeutic tissue healing, or tissue destruction. When treating soft tissue injuries, it can selectively heat structures up to 5cm deep with only minimal increases in skin temperature ( 1Draper, 21). Traditionally, therapeutic ultrasound has been used in sports medicine primarily for its deep-heating effects, but the actual range of biophysiological effects is the property that makes ultrasound such a potentially useful modality (Starkey, 269). Ultrasound is produced by an alternating current flowing through a piezoelectric crystal, such as quartz, barium titanate, lead zirconate, or titanate, housed in a transducer. Piezoelectric crystals produce positive and negative electrical charges when they contract or expand. A reverse or indirect piezoelectric effect occurs when an alternating current is passed through piezoelectric crystal, resulting in contraction and expansion of the crystals. Ultrasound is produced through the reverse piezoelectric effect. The vibration of the crystals results in the mechanical production of high-frequency sound waves (Starkey, 270).

    Depending on the output parameters, the physiological effects of ultrasound application can include many factors. Among these would be increased rate of tissue repair and wound healing, increased blood flow, decreased inflammation, increased tissue extensibility, breakdown of calcium deposits, reduction of pain and muscle spasm through alteration of nerve conduction velocities, and changes in cell membrane permeability (Starkey, 269). Ultrasound passes through soft tissue in the form of longitudinal waves until it strikes bone. When in the bone, some of the energy is reflected and the rest is converted into transverse waves (Starkey, 280). The propagation of ultrasonic energy depends on the frequency of the sound waves and the density of the tissues. When the ultrasound beam strikes an acoustical interface (such as different tissue layers), some of the energy is reflected or refracted. Any energy not reflected or absorbed is passed on to the underlying tissues. The intensity of ultrasonic energy decreases as the distance it travels through the tissues increases. This process, attenuation, occurs through the scattering and absorption of the waves within the tissues. Absorption of the sound waves transfers energy from the beam into the surrounding tissues through conversion of mechanical energy into thermal energy. The amount of absorption that occurs depends on the protein content of the tissues (especially collagen). Tissues such as bone, cartilage, and tendon absorb much more ultrasonic energy than muscle, fat, or blood (Starkey, 281).

D. Neuromuscular Electric Stimulation

    Therapeutic currents are classified as being either alternating, direct, or pulsed. Alternating and direct currents are characterized by an uninterrupted flow of electrons. In pulsed currents, the flow of electrons is intermittently paused. A biphasic, having a bidirectional flow of electrons. When a therapeutic electrical current is introduced into the body, the flow of electrons causes the movement of ions. This current enters the body through a set of electrodes that forms a closed circuit between the generator and the patient (Starkey, 213). Within the tissues, physiological effects are related to current parameters such as neuromuscular stimulation, pain control, control and reduction of edema, and wound healing are evoked (Starkey, 214).

    Neuromuscular Electrical Stimulation (NMES) is used for muscle reeducation, reduction of spasticity, delay of atrophy, and muscle strengthening. The use of electrical stimulation reverses the order in which muscle fibers are recruited into the contraction. Type I fibers do not generate much more force because of their construction. However, they are able to sustain the contraction for a prolonged period of time. Electrical stimulation causes large-diameter type II motor nerves to evoke a contraction before the type I fibers. Therefore, the strength of the contraction is increased because type II fibers are capable of producing more force
(Starkey, 244).

    Neuromuscular electrical stimulation is a frequency-dependent modality. The current must be strong enough to overcome the capacitive resistance of the tissues before the motor nerves can be stimulated. The capacitive tissue resistance is inversely proportional to the frequency of the current. Therefore, the relatively low frequencies used by NMES generators must produce a greater current to overcome this resistance. Muscular contractions obtained through NMES have been shown to increase peripheral blood flow to the extremity being stimulated (Starkey, 245-246).

IV. Usage of Physical Therapy and Athletic Training
A. Why is therapy needed for the proper healing of muscle tissue?

    The principles of therapy have been part of the healing arts since the beginning of recorded time. The instinctive rubbing of a bruise or an ache is a basic form of physical therapy. As early as 3000 BC, the Chinese used rubbing as a therapeutic measure. In 1812, Peter Hanley Ling developed the first scientific basis for therapeutic massage. Hand-in-hand with the development of massage went scientific muscle reeducation or training. Sometimes this was accomplished with mechanical assistance. But, just as often, it involved the therapist moving the limbs of the patient in scientific patterns (physical therapy.htm). Some athletic trainers use physical therapists to supervise the rehabilitation programs for injured athletes while the athletic trainer concentrates primarily on getting a player ready to practice or compete. Also, in addition to being a physical therapist, many are certified athletic trainers (Arnheim & Prentice, 21).
 
 

B. Advantages

    The advantages of receiving therapy are many, whether it is from a physical therapist or an athletic trainer. With a guided, patient-specific rehabilitative program, the patient is guaranteed relief over a period of time. A rehabilitation program is very flexible and easy. What you want to try and do is to go with whatever works. If it works and does not inflict pain on the patient, do it. There are many modalities to be considered for rehabilitation, but I only mentioned the four most commonly used in the field of sports medicine. With exercises designed to strengthen the muscle, and the modalities mentioned above, provides the patient with an optimal environment in order to recover. Together, these two things enhance proper tissue regeneration and possible full recovery after an injury.

C. Disadvantages

    When therapy is not taken advantage of in the injury process, the patient is at a great disadvantage. By this meaning that the muscle tissue will not be properly regenerated, therefore causing it permanent damage. In addition to having permanent tissue damage, the surrounding tendons and ligaments will also be weak. Without therapy, there may be the possibility of surgical intervention, in which the doctor will refer you to therapy anyway. So, to cut the costs of having surgery, it would be much more cost efficient and smarter to go through therapy before anything like this occurs.

D. Controversial Issues Surrounding Athletic Training and Physical Therapy

    In reviewing some of the legal concerns involved in using therapeutic modalities, many other controversial issues evolved. Therapeutic modalities must be used in sports medicine with the greatest care possible. At no time can there be an indiscriminate use of any therapeutic modality. The athletic trainer must follow the laws that specifically prohibit the use of certain therapeutic modalities. Selection of the appropriate modality should be based on an accurate evaluation of the injury and a decision about which modality can most effectively reach the desired target tissue to achieve specific results (Arnheim & Prentice, 308). Two years ago in Indiana, athletic trainers were not allowed to use certain therapeutic modalities in a clinical setting without the consent of a physical therapist. In a clinical setting, an athletic trainer is treated equal to a physical therapist assistant (P.T.A). Here, the physical therapist evaluates and writes a specific rehabilitation plan for the patient and the assistant or athletic trainer performs it. Whereas in a school setting, with no physical therapist present, athletic trainers can do what they want. They are in charge of creating the best possible rehabilitation plan for the patient in that particular setting. Until two years ago, athletic trainers did not have the legal rights similar to physical therapists. Now, athletic trainers can perform the same services as a physical therapist under licensure. Because of this, companies can hire two athletic trainers at the cost of one physical therapist, which puts the therapist in jeopardy. The therapist wants to administer the plan, and guide the patient to completion. This can not be done when they are in a continuous battle with athletic trainers. Companies want to go with what is cheaper, so it is much easier to hire one physical therapist to evaluate and administer, while the P.T.A's and athletic trainers actually carry out the treatment (Kinsey, 1999).

    Another controversial issue is insurance company policies. A number of people predict that insurance policies will damage the health profession field within the coming years. Ten years ago, doctors were considered "God", so to speak. When I say "God", I mean it like a figure of speech so to speak. Many doctors made the decisions of patients, in terms of care needed, regardless of insurance claims, rules and regulations. Unlike today, insurance companies were a lot more lenient. Now, doctors have to follow a certain protocal, in which patientsí options are becoming more limited, due to the lack of insurance coverage (Kinsey, 1999). Now, doctors barely have any authority because insurance companies are regulating their services. This way they can determine the length of rehabilitation given, or time span allowed for recovery. For example, for a patient with a broken leg, they may only allot the therapist a 3 week time period for a full recovery, in which they will provide the funds (Kinsey, 1999). I personally do not agree with this method that is continuing to occur. Every patient is different, whereas it might take one patient 3 weeks to recover, it might be double the time for someone else. Therefore, I think that it is poor judgement on the insurance companies' part to make that decision. This is just one of the ways that they continue to prove that they in essence do not care about their patients well being, only the money that they can save by not providing top-notch services. Also, as a Christian, I thought that we were all supposed to help one another, regardless of race, economic status, or limited insurance coverage? As much as I would like for this to happen, we live in a society which does not allow it. Richard T. Wright stated, "In the moral wasteland that marks the 20th century, ethical principles and moral judgements are desperately needed (Wright, 4). Now is the time, more than ever, to follow this advice. In conclusion, I find that highly unethical, and obviously the individuals in charge of deciding insurance policies in these organizations are showing their true colors.

    While insurance companies are a huge controversy in the medical field, there is also the issue of politics. "How, when and where is athletic training political, and should we be doing about it?" Tony Marek, ATC, MS, who is the district eight director of National Athletic Training Association (NATA), began asking these questions, along with a few others. In order for A.T.ís to consider the ways in which their profession is becoming increasingly affected by politics, they need to ask more questions. "Whoís making the political decisions? Political decisions about what kinds of issues? How might those decisions affect us in ways we never thought of? And most importantly, How can we positively influence those decisions?" (Marek 14). One of the most obvious issues is health care reform. Health care reform is coming, and it will affect them all- certified athletic trainers, physicians, nurses, physical therapists, occupational therapists and so on. They are being asked to see the injured or ill patients and athletes less frequently and asked to take less money for their expertise. What does this mean for the future of A.Tís? Are they better off working outside the system, getting away from HMOís, PPOís, etc., and working on a fee-for-services basis? Marek then states," I sometimes think that we have lost the ability to control how we are treated, by whom and for how long. Health care reform is an issue that is not going to go away. I believe we must actively enter the political arena to debate these issues, whether we think that is the most useful forum for debate or not." (Marek, 15).

    Currently, the NATA is in the process of creating a bill that would add athletic trainers to the list of health care providers that insurance companies should reimburse. Under the new law, athletic trainers are named as health care providers who must be reimbursed for services covered by the insurance company that fall within the licensed athletic trainerís scope of practice. President of the Georgia Athletic Trainerís Association Kelli Sabiston, MA, ATC/L, was one of the professionals that decided to pursue this issue because "they were having problems in the clinical settings."(Hunt, 22). Many of the insurance companies were denying payment simply because the provider was an athletic trainer, not because they did not cover the treatment. Now, the insurance companies must pay an athletic trainer as they would pay any other qualified provider (Hunt, 22). Although there are many controversial issues on this topic, those mentioned above are among the most discussed.

V. Conclusion

    When an injury is sustained, the body sets into motion various processes, which are needed to repair the damaged tissue. A physical therapist or athletic trainer can aid the natural repair processes of tissue by using various therapeutic modalities within an appropriate time shortly after an injury. This paper discussed the physiological effects of therapeutic modalities and their relation to the regeneration process of tissues. By discussing the effects of therapeutic modalities, along with therapy, one can better understand how they can and will continue to be very helpful. The advantages of these are endless, and only in the best interest of the patient. Since I want to become a physical therapist, I thought that doing research on this topic would be very helpful in my own personal interests, and informing others who are interested as well. This paper did not have the "traditional" controversial issues, but none the less, it did have those relevant to this topic. Issues dealing with insurance coverage, credentials, and politics are definitely hot spots in this particular field. As long as these are present, it will continue to be controversial for all athletic trainers and physical therapists involved.
 
 

Bibliography



Arnheim.D, Prentice.W.  Principles of Athletic Training: Eighth Edition.  St. Louis, MO,
 Mosby Year Book: 1993.

Chan.A., Myrer.W., Measom.G., Draper,D.  "Temperature Changes in Human Patellar Tendon In Response to Therapeutic Ultrasound."  Journal of Athletic Training.  Vol. 33 No.2 April-June 1998.

Draper.D, Harris, Schulthies. S, Durrant. E, Knight. K, Ricard. M.  "Hot Pack and
1-MHz Ultrasound Treatments Have an Additive Effect on Muscle Temperature Increase."  Journal of Athletic Training.  Vol. 33 No1. January-March 1998.

Draper.D, Durrant.S, Fellingham.G, Rimington.S.  "Temperature Changes During Therapeutic Ultrasound in the Precooled Human Gastrocnemicus Muscle." Journal of Athletic Training.  Vol. 29 No. 4 Dec. 1994.

Hunt, Valerie.  ìGeorgia Athletic Trainers Gain Reimbursement Law.î  NATA NEWS: News Magazine of the National Athletic Trainersí Association.  October 1999.

Kinsey, A. William.  Certified Licensed Athletic Trainer at Goshen College.
Goshen, IN: November 1, 1999.

Knight, Kenneth.  Cryotherapy Theory, Technique and Physiology: First Edition.
 Chattanooga, TN, Chattanooga Corporation: 1985.

Marek, Tony.  "Politics, Partnerships and The Big Picture."  NATA NEWS:
News Magazine of the National Athletic Trainers' Association.  July 1999.

Myrer.W, Measom.G, Fellingham.G.  ìTemperature Changes in the Human Leg During and After Two Methods of Cryotherapy.î  Journal of Athletic Training. Vol. 33 No.1  January-March 1998.

Seeley.R, Stephens.T, Tate.P.  Anatomy and Physiology, Fourth Edition.
U.S.A., McGraw Hill Company: 1998.

Starkey, Chad.  Therapeutic Modalities: Second Edition.  Philadelphia, PA,
 F.A. Davis Company: 1993.

Wright T. Richard.  Biology Through The Eyes of Faith.  San Francisco, CA.
 Harper Collins Publishers: 1989.

http: www.hia.net/pdesmidt/Physical Therapy.htm.  "The History of Physical Therapy."
 October 1999.