Interferential treatments are historically used for chronic pain conditions such as RSD, fibromyalgia, low back pain, and osteoarthritis but can be very beneficial in post injury, or post surgical procedures, such as knee replacement surgery, acute sports injuries, post operative pain control and will decrease the rehabilitation time needed. Also the permanent physical effects that weaken the affected area can be minimized by increasing cell elasticity.
It is important to note that acute pain and chronic pain are two different types of pain. We have all experienced acute pain from a sudden soft tissue injury, such as a sprained ankle, or even a simple bee sting. The pain is immediate, but as the injured part heals the pain goes away.
Chronic pain does not correlate to an anatomical injury. It is a constant low level painful stimulus to the nervous system that has become a pattern. It may even persist as a “neural memory” after the initial source of irritation has resolved. The nervous system adapts to this chronic stimulation by creating an environment in which events that previously caused no pain become a source of pain. Pain may even progress to uninjured areas such as experienced in sciatica.
Carryover pain relief is the time period following an interferential treatment in which the patient experiences no, or diminished, pain after the treatment is completed. The carryover pain relief period varies depending on the type of pain the patient has, ie. acute or chronic. As a general rule the patient who has an acute pain episode, but is doing rehabilitation exercises, will have a shorter carryover period of relief. There are physiological reasons for this and the reduction of permanent injury to the affected area can be minimized. The purpose of the rehabilitation is to minimize non natural tissue creation, such as scar tissue, which causes permanent weakening of the structure and decreased blood blow, as well as loss of tissue elasticity, referred to as 'hypertonia'.
Scientists have known for a long time that human epithelial tissues loses elasticity with aging. It has been implicated in the pathogenesis of many progressive diseases of aging, including hardening of the arteries, joint stiffness, cataracts, Alzheimer’s and dementia. However, previous researchers believed the reason for the loss was only the “glue” that seals the epithelial tissues, so called extra cellular proteins such as the elastic protein titin, rather than the cells themselves. Many treatments of diseases caused by cell elasticity loss have been based on this assumption. Many post injury treatments are also predicated upon maintaining muscle elasticity.
There are myriad chemical changes that occur on the cellular level in our bodies following an injury. The individual cells react to the immediate acute situation, which is usually caused by some traumatic occurrence, and react differently than they do in chronic pain syndromes.
Force is everywhere in our biological system. If we were to sprain an ankle, or dislocate a shoulder, the force from that trauma would activate a chemical response to the cells such as leukocytes leaving the blood stream squeezing through blood vessel walls going to the injury area. Prior to acute injury the leukocytes would primarily patrol looking for an injury and not sensing one would not exit from the blood stream. Once the injury is noted then the processes of combating infection, allowing the exit of numerous endogenous chemicals would be allowed by the introduction of histamines which allow transport of the chemicals to the area they are needed. The process itself only allows transport to the affected area and not throughout our body which is the normal state of health - absence injury.
Following the injury many primitive cells which we know as "stem cell like" are introduced into the area. The reason for the primitive cells are they have the ability to differentiate and specialize. This means the primitive cell as it divides to replace the diseased or destroyed cells can become cells of specialization such as bone, tendon, ligament, skin, blood, and other cells that are necessary to replicate the former cells. Mature cells, that have specialized, do not have this ability.
The key to carryover pain relief with acute injuries is rehabilitation or stretching of the repaired tissues. It is necessary for the patient to regain function and not be limited due to inelasticity of the repaired tissues or rigidity of the cell walls. Where there is an abundance of non-natural cells which combine to form tissues there needs to be more cells with the exact functions as the structure had prior to injury. In rehabilitation exercises it is a process of constant stretching of the cells and tissues to maintain and increase flexibility. In knee replacement surgery it can be something as simple as a 'constant motion device" which is nothing but a device that moves the knee joint back and forth immediately post surgery to maintain flexibility. The key is the "re injury" on the cell walls allows for better cell differentiation which is beneficial in the overall healing process. Lack of mobility generally leads to extended injury and permanent painful limitation of motion.
In rehabilitation there is basically one overriding difference and that is the pain is induced over and over in acute injuries by rehabilitation exercises. The process of movement slowly creates micro tears in the tissue which aids in increasing muscle flexibility as well as allowing cellular differentiation minimizing the ever increasing scar tissue. According to some literature it has been reported that scar tissue likes to become bone tissue which is extremely inflexible. The muscle chemicals and electrical charges can communicate with our central nervous system and the induced pain is created by our muscle stretching. In essence, for gain there is pain, and the carryover relief period is due to constant micro re injury for overall long term gains.
Fortunately rehabilitation exercises can be done while being treated with interferential or tens therapy and pain is reduced for greater range of motion and decreased rehab. time following injury.