Carpal tunnel syndrome is compression of the median nerve in the wrist. The median nerve travels in a small tunnel called the carpal tunnel. The carpal tunnel has other tendons that primarily allow you to bend your fingers and thumb. Over the tunnel is a roof layer called the transverse carpal ligament. When the ligament is tightened, it causes compression of the nerve. The compression of the nerve causes the symptoms of carpal tunnel, including numbness or tingling in the fingers or hand, pins and needles, difficulty with manual dexterity, a clumsy feeling with the hand, the propensity to drop different objects, and sometimes weakness.
Causes of Carpal Tunnel Syndrome
There are several different causes of carpal tunnel syndrome. The literature has shown that some repetitive maneuvers can cause it. General things like obesity, fluid shifts that can occur during pregnancy, arthritis and common conditions such as hypothyroidism and diabetes are causes. In rare cases, certain traumatic events or mass lesions like a cyst, as well as other rare syndromes such as amyloidosis, sarcoidosis, multiple myeloma and leukemia can also be associated. In general, however, we don't often have a cause or a reason for carpal tunnel syndrome but it is incredibly common.
Diagnosing Carpal Tunnel Syndrome
When you come to the office, you’ll be diagnosed with a history and a physical exam. Patients with carpal tunnel often experience the very classic signs and symptoms of the disease, and there are a number of physical exam maneuvers that I like to do to confirm the diagnosis.
The first maneuver is the Phalen test and that involves flexion of the wrist (bending the wrist down) which closes down the tunnel that the median nerve travels in. That increased pressure causes nerve symptoms that are reproduced such as numbness and tingling at the time of doing that test. The second maneuver is a Tinel sign where I tap on the patient's wrist, eliciting changes within the median nerve if it is compressed. The Durkan's maneuver is another physical exam test where I compress the base of the palm right over the carpal tunnel, which again elicits paresthesias in the nerve distribution if carpal tunnel is in fact the diagnosis.
When the diagnosis is uncertain, there are other tests that we also can do, including nerve conduction studies and EMG. These are tests that specifically look at the nerve and measure conduction velocity as well as the muscles that supply the nerve to give you a better sense of if there's been any damage to the nerve, and whether that damage is mild, moderate or severe. More recent data has also shown that ultrasound can be a non-invasive diagnostic modality that shows flattening of the nerve if there is compression within the carpal tunnel.
Treating Carpal Tunnel Syndrome
In general, it is always the preference to treat with non-operative measures. In the case for carpal tunnel syndrome, this involves 3 different things. The most common is a wrist brace. The wrist brace functions by a metal bracket on the palm side of the wrist that keeps the wrist in a neutral position. This prevents the wrist from being excessively flexed or extended as those positions often exacerbate carpal tunnel syndrome. You may find that carpal tunnel symptoms are worse at nighttime and that's because most people sleep with their wrist either flexed or extended and that decreases the amount of volume in the carpal tunnel. Patients will often complain that they wake up in the middle of the night having to shake out their fingers in order to restore some of that sensation.
When the cause is due to inflammation, over the counter anti-inflammatory medications can also help, such as Motrin, Advil, or Aleve. The next step is a steroid injection. Cortisone functions as a pain reliever and a strong anti-inflammatory directly into the carpal tunnel. This is something that is usually very well tolerated and performed in the office with local cleaning and a numbing spray. Sometimes this can be also performed with ultrasound guidance. The benefit of the steroid injection is both diagnostic and therapeutic. That means that if the diagnosis is uncertain, relief with a standard injection supports the idea that carpal tunnel syndrome is the diagnosis. It certainly can also help with some patient symptoms and provides a nice in-between ground before the next step.
If the compression on the nerve is in the moderate or severe category, or patients are symptomatic enough that they would like a definitive solution, we then begin talking about operative treatment. Operative treatment can look many different ways, either with an open carpal tunnel release, a mini-open carpal tunnel release, or newer versions, including endoscopic carpal tunnel release. In all of these cases, the goal is to cut the transverse carpal ligament, which is that thick band of tissue that compresses the median nerve. In doing so, you are able to relieve the pressure on the median nerve, and that allows the body to then recover some of the damage that has been done to the nerves.
My advice to patients is always never to wait until the symptoms become so severe that the changes are irreversible. Literature has shown us that the patients that do the best with the carpal tunnel release are those in the moderate category because that gives the patients the best chance to recover some of their function. Patients will often report that the first thing that they notice after a carpal tunnel release procedure is relief of nighttime symptoms. No symptoms will ever reverse themselves completely, but our goal with the carpal tunnel release is to halt any progression of damage to the median nerve.
Frequently Asked Questions
How do you tell the difference between carpal tunnel and arthritis?
Carpel tunnel has a number of very specific symptoms that arthritis does not. Arthritis can have associated pain and swelling and the fingers can also feel clumsy and weak. However, carpal tunnel syndrome usually has numbness and tingling in a very characteristic distribution. It typically involves the thumb, the index finger, the long finger, and half of the ring finger. Sometimes patients experience numbness where the entire hand tends to fall asleep, but typically the median nerve supplies those 3 and a half fingers. We look for the numbness in those fingers as well as reactions to the physical exam maneuvers that may come from compression of the median nerve.
In addition, if we wanted to look at arthritis as a possible cause, x-rays can be helpful to see if there are any bone spurs and location of pain there in relationship to where the arthritis is on those x-rays can confirm a diagnosis of arthritis versus a nerve related issue.
If someone has confirmed carpal tunnel, are there any risks of using a brace when symptoms appear and discontinuing the brace when symptoms are better?
It is possible that carpal tunnel can stay in that mild category where I would recommend the brace, especially with activities if that helps to stop some of the symptoms. We do know that over time the scar tissue on the median nerve can cause compression of the median nerve to the point that that damage becomes irreversible. That's where the nerve studies can be helpful because they give you a sense of whether the median nerve damage is in the mild, moderate or severe category. If it is in the moderate or severe category, that's when we have a discussion regarding either a steroid injection or potentially a carpal tunnel release. Our goal is always to avoid long damage on the median nerve because it does get to a point where some of that damage becomes irreversible. But it's always a discussion between the patient and the provider.
If you have a carpal tunnel release, how long are you unable to use your hand and wrist?
Carpal tunnel releases, as we reviewed, happen in many different categories. In general, most providers would allow you to take the bandage off in the first 2 or 3 days after surgery and generally use the hand. I use the soft bandage and I encourage my patients to take that off at 3 days after surgery and get it wet in the shower at that point. And keep the wound clean and dry with a waterproof bandage.
I would expect that most patients would be able to return to work if they are doing typing or other manipulative site tasks. Those that are involved with heavy labor or need strong gripping maneuvers for their jobs can usually return to work in 2 to 3 weeks. Generally, once the wound has healed, most patients are very happy with relief of their symptoms and are eager to get back to doing what they love to do. Sometimes that can happen as soon as 3 or 5 days after surgery, but certainly would be expected within that 2 to 3 weeks.
Can you do hand therapy exercises before or after surgery or instead of surgery to help out?
Hand therapy can function to get you back to activities of daily living by showing you slight, ergonomic adjustments so that you're not flexing your wrist excessively or extending it extensively, which would compress the median nerve. They also can provide you with different forms of custom splints and teach you different exercises to maintain your mobility even if you aren't looking for a surgical procedure. In the post operative period, I found that most patients actually don't require hand therapy because the relief provided from a carpal tunnel release allows them to get back to doing what they like doing and the mobility comes on its own. If we do require occupational or hand therapy, they are very helpful in terms of teaching scar massage as well as teaching exercises to increase the mobility of the hand and the fingers.
Are heat or ice useful to reduce symptoms?
Both heat and ice can be used to reduce symptoms. If one feels better than the other, use it. In general, if the hands feel swollen and inflamed, ice can be better. I encourage my post-operative patients to use ice as well. In general, if the hand feels very stiff, especially if there’s arthritis or other issues with finger flexibility, then heat is helpful to warm the fingers and allow you to maintain motion.
Does someone need a second carpal tunnel operation in the future?
Carpal tunnel surgery is one of the most successful operations in orthopedic surgery and especially hand surgery. The relief rate for carpal tunnel release is somewhere in the 95 to 98% success range. It's one of the best operations we have to offer for how little downtime there is in the recovery process. However, no surgery is a hundred percent guaranteed. In that 5% range, there is a subset of patients who may have recurrence of their symptoms.
When symptoms reoccur, it may be due to the incomplete release of the transverse carpal ligament. If it recurs several years after the original surgery, new scar tissue may be causing pressure on the median nerve. When carpal tunnel syndrome recurs, we follow the same steps as the first time. If it's mild, we try non operative measures with a wrist brace, over the counter medication and potentially a steroid injection. In the case of any revision surgery, it would be wise to consider additional diagnostic tools such as a nerve conduction study or an ultrasound to give definitive evidence on whether or not the median nerve has been compressed. If it has been compressed, we can proceed with a revision carpal tunnel release. In that case there is a slightly larger incision to make sure that any scar tissue or band surrounding the nerve are fully and completely released. Thankfully, most patients do very well after revision carpal tunnel surgery.
If someone has pain in their thumb from using their phone too much, is that carpal tunnel pain or is that something else?
The pain could be from any number of things. The use of the phone in everyday life has caused several different issues, including arthritis at the base of the thumb as well as carpal tunnel syndrome. Because there are so many fine and intricate structures in the hand and wrists, it's something that we would explore fully in detail with the patient when I see them in the office with a detailed history and detailed physical exam.