How the Body Repairs Damaged Tissue
By Christy Cael
Originally published in Massage & Bodywork magazine September/October 2011. Copyright 2011. Associated Bodywork and Massage Professionals. All rights reserved.
Many people arrive at my office injured, afraid, frustrated, bewildered, and in pain. Occasionally, they view their bodies as enemies that have betrayed them. My job is to act as a liaison between my clients and their bodies. One of the most valuable services I offer is helping clients understand the healing process, in a meaningful way, and empowering them to get involved.
A critical step in developing this ability is deepening your understanding of how the body repairs damaged tissue. You must recognize specific events that occur following an injury and common signs and symptoms associated with tissue damage and repair. This will help you identify where clients fall in the healing continuum, what sensations and functional changes they might expect, and ways you can both support the restoration of optimal function.
Phases of Healing
We can break tissue healing into three phases: the inflammatory response, repair phase, and remodeling phase. Each phase has a specific purpose and is characterized by common signs and symptoms.
Healing begins immediately following a traumatic injury with the inflammatory response. The magnitude of this response depends on the severity of tissue damage and may vary from one person to another. In this phase, injured tissues release chemicals that draw resources to the area, alert the body that damage has occurred, and inhibit function to prevent further injury. Five cardinal signs characterize inflammation and can be remembered with the acronym SHARP: swelling, heat, a loss of function, redness, and pain.
Initially, surrounding blood vessels dilate, increasing blood flow to the injured area. This delivers the white blood cells and nutrients necessary to clean up and wall off the injured area. Affected tissue becomes hot and red as blood flow increases. Over time, capillaries become more permeable or "leaky," allowing nutrients, white blood cells, and clotting proteins to move out of the circulatory system and into the damaged area. Affected and surrounding tissues become swollen and may feel boggy since plasma, the fluid component of blood, also leaks into the area.
The pain sensation produced during the inflammatory response is global (felt in a large area) because it is chemically induced and affects both damaged and surrounding tissues. Clients typically describe constant pain over a broad region that significantly limits function. They may have difficulty isolating the injury location during this initial phase and difficulty resting or sleeping is common. These symptoms continue as long as the inflammatory chemicals remain active within the tissue.
A secondary purpose of the inflammatory response is to limit function in the injured area. Forces or activities that injured the tissue must be stopped in order to prevent additional tissue damage. Swelling, muscle spasm, and pain inhibit function and clients typically experience a loss of mobility, strength, and endurance as a result. Alternate movement strategies or compensation (like limping on an injured ankle) may occur immediately following injury. Compensation is normal and necessary to minimize further injury while maximizing function. Educate clients about the purpose of inflammation to help decrease the stress and frustration associated with acute pain and loss of function.
The inflammatory response gives way to the repair phase once the injured area is walled off and debris from injured structures is removed. Signs and symptoms of inflammation subside and construction begins to replace or repair the injured tissue. Clients often report more specific areas of pain as the chemicals of inflammation dissipate and healing processes centralize in areas of damage.
During the repair phase, new blood vessels grow in the injured area, maximizing transport within the tissue. This new transport network delivers materials necessary for repair and removes metabolic waste. Fibroblasts, cells that generate extracellular matrix and collagen fibers, begin producing granulation tissue, a fragile form of scar tissue, filling gaps left after the removal of damaged structures.
The amount of granulation tissue produced and time required for repair depends on the extent of tissue damage and ability to deliver the necessary materials for construction. Once adequate granulation tissue is produced, temporary vessels are deconstructed and fibroblast activity decreases. The tissue is now ready for regeneration of new cells or production of permanent scar tissue.
It is important to note that granulation tissue will not tolerate forces required for full return to activities of daily living. Clients are tempted to test the injured area as inflammation and pain localize, symptoms become more intermittent, and function improves. Because of this, reinjury is common during the repair phase, sending clients back to the beginning of the healing process. Educate clients about the fragility of granulation tissue and advise caution when returning to activities previously modified or avoided due to pain and inflammation.
The third and final phase of the healing process requires construction of permanent tissue, typically strong scar tissue made from a dense network of collagen fibers. As function returns and various demands are placed on the new tissue, the structure must be reconfigured to adapt. It does so by deconstructing and reconstructing the collagen fibers according to specifically applied forces for maximum strength and flexibility. This process of aligning collagen fibers along the lines of stress is called remodeling and is the primary purpose of the final phase of healing.
Initially, the collagen fibers that form the substance of mature scar tissue are arranged randomly, spreading in all directions. As forces are placed through the tissue, some collagen fibers are destroyed, allowing greater flexibility, while others are reinforced, providing increased strength. The collagen network continues destroying fibers that limit necessary motion and reinforcing fibers that resist tension as greater and more varied stresses are applied to the tissue. Ideally, the new tissue will offer maximal flexibility and strength, according to the demands placed on it during the remodeling phase.
The pain associated with inflammation gives way to that of ischemia during the remodeling phase. Blood flow to the injured area decreases as capillaries are deconstructed and mature scar tissue forms. Clients overwhelmingly report decreased mobility as dense networks of collagen replace granulation tissue, making soft tissue less pliable. Pliability may be further diminished if adhesions form between fascial layers in affected and associated areas. Trigger points often develop during this phase due to increasing ischemia.
If compensation has been necessary throughout the healing process, chronic dysfunction may occur in associated structures. This includes hypertonic muscles, abnormal movement patterns, and referred pain from trigger points. Many of my clients become frustrated as pain moves to new areas (associated structures from compensation) and mobility decreases. Again, this is quite normal and indicates progress through the healing process.
Remodeling may take months or years, depending on the severity of injury and demands placed on the tissue. Success in this phase requires gradual progression of functional activities followed by appropriate tissue adaptation. Encourage clients to return to activities previously modified or avoided with the intention of retraining the injured tissue (with physician permission, of course). Help them recognize compensatory patterns, improve body awareness, and return to more functional movements. Supervised activity may be necessary to restore full function, requiring assistance from physical or occupational therapists or fitness professionals.
Supporting the Healing Process
There is no specific time frame associated with the individual phases of healing. Several factors, including the amount of damage, location, type of tissue injured, general health of the client, preexisting conditions, medications, nutrition, and hydration all influence the time needed to repair injured tissue. We must rely on signs and symptoms rather than time frames to determine when clients have moved from one phase to the next and how best to support the process at any given time.
Support the inflammatory response by limiting use of the injured tissue. This allows the body to isolate the injured area, clean up debris, and mobilize supplies necessary for repair. Focus your treatment sessions on associated structures while avoiding direct manipulation of injured tissues as the body completes this process. Traditional management of acute inflammation includes protection, rest, ice, compression, and elevation of the injured area (PRICE), which minimizes further injury and decreases inflammation.
Massage also supports healing by helping clients shift from a sympathetic nervous response (fight or flight) to a parasympathetic response (relaxation). Stress associated with injury, whether from pain, physical reactions, or emotional responses, diverts energy and resources away from repair processes. It may also interfere with sleep, additionally limiting healing. During the inflammatory response, work with clients and their health-care team to reduce pain and stress and achieve adequate sleep to maximize healing.
As the inflammatory response gives way to the repair phase, your efforts shift to maintaining function, minimizing compensation, and increasing circulation. Direct techniques continue to focus primarily on associated structures, but you may now begin addressing injured areas more specifically as inflammation subsides. Remember, clients will experience less pain (localized and intermittent rather than global and constant) and improved function, but don't be tempted to work too aggressively on affected tissues. Remind them of the fragility of granulation tissue and the consequences of overuse.
Once the remodeling phase begins, treatment becomes much more aggressive. Focus on breaking up scar tissue and adhesions, increasing range of motion and circulation, and eliminating compensatory movement patterns. Clients embark on a systematic return to normal activities as you work together to achieve optimal tissue alignment and coordinated movement. This may require professional oversight from therapists who specialize in therapeutic exercise and neuromuscular reeducation.
Recognize specific events that occur following an injury and common signs and symptoms associated with tissue damage and repair. This helps you identify where clients fall in the healing continuum and anticipate what sensations and functional changes they might expect. Reduce fear and frustration by explaining the events following an injury and highlight ways you and your client can both support the healing process.
Christy Cael is a licensed massage therapist and certified strength and conditioning specialist. Her private practice focuses on injury treatment, biomechanical analysis, craniosacral therapy, and massage for clients with neurological issues. She is the author of Functional Anatomy: Kinesiology and Palpation for Manual Therapists (Lippincott Williams & Wilkins, 2009). Contact her at firstname.lastname@example.org.