You may think your dog is the peace-loving sort of pet, but I can assure you that its body is designed for war!
Similar to the human, a dog’s body reacts to trauma or disease with an all-out fight!
At the onset of any injury, the “troops” are sent in. White blood cells saturate the area, especially in cases of infection by foreign objects and by bacterial or viral organisms. “Weapons” are discharged in the form of histamines. This causes blood vessels to dilate, increasing blood flow to flush out damaged areas.
To further provide protection and defense, cellular fluids leak into the tissues. This results in redness, warmth, swelling, and acute inflammation.
The healing process
When the fight is over, the healing and repair phase begins.
Here is where we encounter the formation of scar tissue. The body does this by building a scaffold of sorts in and around the injured area.
Various cells produce and release chemical messengers that communicate between other cells. In response, cells begin to manufacture “glycoproteins” which are molecules that form the support structure, similar to bricks and mortar.
Fibrous bands of collagen form with a glue-like gel matrix, as the protein molecules, combine with oxygen, acids, and minerals in the body.
Together they become scar tissue and provide a temporary framework to fill in the damaged spaces, bind tissues together and hold the injured area intact, while the body attempts to grow normal tissue back.
In other instances, it becomes the permanent replacement to normal tissue but is always inferior to regeneration.
There are 2 interesting traits about scar tissue that impact the dog and determine what physical therapy treatment will be needed:
1. Proliferation
Scar tissue grows in various amounts per individual animal or human. Some bodies seem to grow scar tissue in overabundance, compared to others. This may be related to the particular patient’s natural immune response to trauma. For animals that grow more scar tissue than others, the extra time and attention to treatment may be needed.
2. Random arrangement
Scar tissue is rather tough and inflexible. As it forms, it does not arrange itself in consistent patterns. It is laid down in mixed, random arrangements. This makes it less resistant to tension and therefore can be broken down through stretching, deep massage, pulsed ultrasound, extracorporeal shock wave therapy and laser.
In particular, stretching is the key component of scar tissue removal. Massage and other physical modalities must be followed with stretching.
Forming of scar tissue
If your dog has sustained an injury, scar tissue will form in varying amounts.
If the injury is at or near a joint or in a large muscle belly, the scar tissue may be “too much of a good thing “and cause impairment in function with restricted range of motion.
In these cases, your veterinarian will show you how to stretch the area or refer you to an animal-trained physical therapist or chiropractor for additional expertise in the best way to break the adhesions.
You may be concerned that this sounds painful for the animal, but with proper use of physical agents to pre-soften (such as ultrasound, laser or shock wave), skilled manual techniques, comfortable body positioning and gentle soothing assurances to the pet, it can be well tolerated.
Conversely, there are instances when scar tissue is good and better left alone!
Functional scar tissue
In situations where there is instability, scar tissue can provide some protection and support. A few examples are:
1. Partial cranial cruciate ligament tears
Surgery may not be necessary or desirable, and scar tissue helps tighten the residual portion of the ligament that remains attached. Scar tissue now becomes your dog’s friend!
2. FHO surgery
When the ball of the femur is surgically removed, it is blood callous and scar tissue that fills in the void and forms a “pseudoarthrosis” or artificial soft cushion. Scar tissue is desirable in this case!
3. Medial shoulder instability
Some sporting and agility dogs may develop this condition, similar to a dislocated joint. It often requires surgery and is followed by a long healing phase where activity and motion are restricted. Stretching is absolutely contraindicated as it will break apart or tear the desired scar tissue.
Understanding the basics of scar tissue can be important when faced with an unexpected injury to your dog!
Your veterinarian and physical therapist can help you determine when scar tissue should be left alone or when treatment is needed because it’s just too much of a good thing!
Related articles:
Canine Core Strengthening Exercises: Paring Down to the Canine Core
Further reading:
The Biology of Scar Formation