Carpal Tunnel Syndrome is one of those conditions which is commonly overdiagnosed. It seems that any sort of hand and wrist pain or tingling and numbness automatically equates to carpal tunnel syndrome. This over-diagnosing, in my opinion, occurs because the real cause of the condition is usually mistaken. For those who actually have the condition, it can seem like there are no good answers for why it occurs and why it continues to be a problem. Hopefully, I can clear up some of these questions and give you a better understanding of what carpal tunnel syndrome really is, and thus a better understanding to treat it.
The Carpal Tunnel is actually an anatomical structure, not just the name of a condition. It is located in the anterior wrist and is formed by the carpal bones which form the bottom “C” shape of the tunnel and the transverse carpal ligament which forms the top. This small “tunnel” is where the flexor tendons of the fingers and thumb, and the median nerve pass through as they course into the hand from the forearm. The important fact to know about this anatomy is the close proximity of the structures involved and how they interact with each other.
The specific muscles involved in the carpal tunnel are the Flexor Digitorum Supericialis, Flexor Digitorum profundus, and Flexor Pollicis Longus along with their coinciding tendons and sheaths. By the time these muscles reach the carpal tunnel, they have separated into tendons which then course to each finger within their own sheath. Because of this, there are nine individual tendons and one nerve inside the carpal tunnel. That is a lot of moving parts inside a small area.
Now that we have an idea what the carpal tunnel consists of, and how many structures are inside within very close proximity, it makes sense why this area could be a problem. However, the question still arises as to why problems occur in the first place? To understand why we need to know the principals of repetitive stress injuries. The graphic below demonstrates the cumulative injury cycle and repetitive stress injuries quite well.
Before reading on, I highly recommend reading my post on cumulative injury cycle (Cumulative Injury Cycle.. I pulled My hammy Again?!) to get a detailed view of these kinds of injuries. It will give you a much better understanding of the principles.
Here are the basics of a repetitive stress injury as follows: a trauma occurs in the muscle (this could be anything from slight overuse to a traumatic tear to the tissue). Inflammation occurs leading to scar tissue formation as part of the healing process. This scar tissue creates decreased blood flow; decreasing muscle health, flexibility and strength. Because of this weakened state, the muscle now must work harder to achieve the same performance that was once much easier. This increased workload creates the potential for re-injury, starting the injury cycle over again.
So, How Does This Type of Injury Cycle Apply to Carpal Tunnel Syndrome?
Commonly, carpal tunnel syndrome occurs in individuals who use their hands for a living. This includes office workers, factory workers, musicians, and of course manual therapists. The reason for this is simple. As the muscles of the hand and forearm (aka the specific muscles within the carpal tunnel) are used for repetitive tasks such as typing, screwing bolts, or massaging for 5 hours, those muscles are receiving mico-traumas which are the beginning of the repetitive injury cycle. This may not seem like a serious injury at the time (or even felt). However, the injury and recovery process are the same; leading to scar tissue being present and weakening the muscle.
This creates the potential for the cumulative injury cycle to begin. As those same muscles are used repeatedly, day after day, week after week, month after… you get it, those micro-traumas add up and can lead to soreness, pain and eventually even chronic inflammation. When this happens, the structures within the carpal tunnel become thickened and swollen, compressing the structures inside the tunnel leading to carpal tunnel syndrome.
Because the flexor tendons are the structures involved, any sort of grasping or use of the fingers and thumb can be painful and aggravating. The more these muscles are used the worse the symptoms can get. Also, because the median nerve is located within the carpal tunnel, it gets compressed as well, causing tingling and numbness. This is usually the symptom that most people recognize as carpal tunnel syndrome.
Carpal tunnel syndrome symptoms are usually the result of chronic over usage of these muscles. Rarely does carpal tunnel syndrome simple appear quickly. The symptoms might, but the underlying cause will have been developing for a long time. Usually, carpal tunnel syndrome will occur in a person who has been working in a profession where the hands are used on a consistent basis. It may take a few months to develop, or it may take a few years. However, the underlying injuries within the involved tissues will have been present well before acute carpal tunnel symptoms are felt.
So How Do We Treat Carpal Tunnel Syndrome?
Optimally, we would treat the affected muscles early on, even before acute carpal tunnel syndrome symptoms are felt. However, this is difficult to do simply because the client does not know what they do not know. In other words, if nothing is felt, they will not be coming in to receive treatment for it. However, knowing what profession a client is in can guide your ongoing care for them. Simple treating the muscles involved on a semi-frequent basis will deter carpal tunnel syndrome from occurring. And as we all know, for someone who works with their forearms and hands all day, it feels good to have them worked on anyway!
Since early treatment is not always possible, the acute treatment of carpal tunnel syndrome relies on the release of specific muscles. These muscles are flexor digitorum superficialis, flexor digitorum profundus, and flexor Pollicis longus. These are the primary muscles which cause swelling within the carpal tunnel, leading to acute pain. Since these muscles are used for so many tasks, it is easy to see that they would become affected and cause these issues.
The release of these muscles by focusing on the treatment of scar tissue and adhesions should be three-fold. First, scar tissue should be addressed within these individual muscles where traumas have occurred. Usually, this is multiple locations by the time true carpal tunnel syndrome is present. Second, scar tissue and adhesions in between muscles and tendons need to be addressed. Many times, adhesive tissue will form in between layers of muscles during the healing process of the injury cycle. Specifically, in the forearm, adhesive tissue can form between the individual tendons of the flexor digitorum superficialis as well as the individual tendons of the flexor digitorum profundus. This occurs superior to the carpal tunnel, (see above illustrations) creating even more restriction and irritation in the area. Third, fascial shortening will have occurred making flexibility in the forearm and hand limited. The need to address these fascial restrictions throughout the hand, especially in the transverse carpal ligament is important. Sometimes the entire palm of the hand will have fascial tension within the palmar aponeurosis contributing to the discomfort.
By releasing the adhesive tissue and scar tissue present in these specific muscles and tissues, the injury cycle is disrupted. When scar tissue is released, it allows for increases circulation within the tissue, thus allowing for strength and flexibility to return. Once normal function begins to return to the affected muscles, swelling and inflammation will decrease, allowing for less compression within the carpal tunnel. As swelling subsides, the median nerve is no longer compressed and the flexor tendons are no longer irritated with room to glide normally. Carpal Tunnel Syndrome fixed. Of course, this makes it sound simple when in reality this can take multiple treatments and time off of work to rest, allowing for healing to occur. However, the important thing to know is this; the root problem is being treated. With this sort of treatment, yes, the symptoms will improve, but the core condition is being treated and not just covered up with medications or a wrist brace.
With this knowledge in mind, it makes sense why carpal tunnel syndrome symptoms seem to continue returning with the common treatments which are prescribed. The first and most common is simply immobilizing the hand and wrist with a brace or splint. The theory behind this is to brace the wrist so movement is limited. This is basically forcing the muscles to rest. The problem with this treatment is that while rest may create some relief short term, as soon as the activity is resumed, the unhealthy and scar tissue-laden muscles will quickly re-irritate and swelling will return. This is not a cure.
Secondary treatment can include steroid injections to alleviate inflammation and swelling. Once again, this may take away the symptoms for a brief period, but once the injection effectiveness has worn off, symptoms will return.
Lastly, carpal tunnel surgery involves cutting the transverse carpal ligament (aka the top of the carpal tunnel) to relieve pressure within the carpal tunnel. This is an effective treatment and does cause symptom relief in many cases. However, it can lead to increased amounts of scar tissue present within the area which can cause carpal tunnel symptoms to return as well as other dysfunction in the area.
All of these common treatments do not address the root cause of the condition; that being the scar tissue within the affected muscles and tendons. While I understand that there are certain times when surgical intervention or medication is needed for severe cases, It is certainly not the only way to treat the condition. Without addressing the root cause, the condition will not go away unless the activity causing it is stopped (which usually means ending a career or important daily activity) or successful surgery is accomplished. Both are not good options.
By using our knowledge of anatomy as well as some physiology know-how, we are able to treat a common condition which affects many people (including many of our own peers). Although many treatments may have been tried by a client, this one will actually get to the source, and hopefully, bring healing to the condition.
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