Carpal Tunnel Syndrome
What is the Carpal Tunnel?
The carpal tunnel is a space under the base of the palm that the median nerve (one of the major nerves to the hand) runs through. The carpal tunnel has rigid, unyielding boundaries: Its back and sides are made up of the wrist bones and its front, just under the palm, is made up of a very thick ligament, the ‘transverse carpal ligament’. The median nerve provides sensation to the thumb, index finger, middle finger and half of the ring finger. It also controls the group of muscles at the base of the thumb. The median nerve runs through the carpal tunnel accompanied by the nine tendons that flex (bend) the fingers and thumb, and the tendons’ lining, which is called ‘tenosynovium’.
The transverse carpal ligament (transverse light purple structure) covers the carpal tunnel. The Median Nerve (yellow) can become compressed underneath the transverse carpal ligament.
What is Carpal Tunnel Syndrome?
Carpal Tunnel Syndrome occurs when the median nerve becomes compressed in the carpal tunnel. As the boundaries of the carpal tunnel are rigid, and it contains only a limited amount of space, anything that takes up too much space in the carpal tunnel can compress and damage the median nerve. Carpal tunnel syndrome is, pure and simple, a space problem: there’s too much stuff in too little space. The most common thing that takes up too much space is the tenosynovium (tendon lining), when it swells up.
What are the Symptoms of Carpal Tunnel Syndrome?
The symptoms of carpal tunnel syndrome come from irritation of the median nerve. Remember that the median nerve supplies sensation to the thumb, index finger, middle finger and half of the ring finger, as well as motor control to the thick muscles at the base of the thumb.
The symptoms of carpal tunnel syndrome include the feeling that the thumb, index fingers, middle finger, and occasionally the ring and small fingers are “numb”, “asleep”, “cold”, “lack circulation” or have “pins and needles” in them. Carpal tunnel syndrome is usually worst at night, or upon awakening in the morning, because we all sleep with our wrists flexed down, which further “pinches” the median nerve. If you wake up at night with your hand numb or painfully asleep, and have to “shake out” your hand to get relief, you’ve got carpal tunnel syndrome. This is why splinting the wrist at night often helps people with mild carpal tunnel syndrome – it keeps the median nerve from getting pinched during sleep. The other reason why carpal tunnel syndrome is worst at night is because we tend to swell more at night. This swelling takes up space, further compressing the median nerve.
The symptoms of carpal tunnel syndrome are also worse with gripping, as gripping increases pressure in the carpal tunnel. This commonly occurs when driving, writing or holding books, cell phones, performing heavy labor, etc. Prolonged wrist extension, such as occurs during long bike rides, may also decrease the space available. Eventually, as carpal tunnel syndrome progresses over time, the fingers may permanently lose sensation. The muscles that move the thumb may not work well, and over time can atrophy (die).
Carpal tunnel syndrome may involve the small finger, but only when other fingers are involved. If it’s only the small finger involved, then the problem is probably cubital tunnel syndrome, which is compression of the ulnar (funny bone) nerve about the elbow.
How is the Diagnosis of Carpal Tunnel Syndrome Made?
The diagnosis of carpal tunnel syndrome is made by history and physical examination, i.e. by a hand surgeon talking to you and examining your arm. A symptom that is classic for carpal tunnel syndrome is waking up in the middle of the night with your hand tingling or “numb”. If you flick your wrist to try to get rid of the numbness, you almost certainly have carpal tunnel syndrome. A thorough physical examination can evaluate the state of multiple nerves. There are other places in the arm where the median nerve can be compressed, which can lead to symptoms very similar to carpal tunnel syndrome. In unusual cases, these other potential sites of entrapment should be evaluated because they will not be relieved by a carpal tunnel release. It is also important to determine whether or not the ulnar (funny bone) nerve is involved (i.e. whether or not Cubital Tunnel Syndrome is also present).
Nerve conduction studies are usually obtained, but they are far from perfect. In fact, they fail to diagnose approximately 20-33% of people with carpal tunnel syndrome.
In the event that the history and physical examination strongly suggests carpal tunnel syndrome, but the nerve conduction study is negative, a steroid injection is indicated. An injection into the carpal tunnel is probably a better diagnostic test than the nerve conduction study. If the injection helps your problem, even for only a few days, then the diagnosis is almost certainly carpal tunnel syndrome.
How is Carpal Tunnel Syndrome Treated?
Unless the carpal tunnel syndrome has been around for a long time, leading to permanent nerve damage, initial treatment often involves splinting the wrist at night.
If that doesn’t work, carpal tunnel syndrome should be cured by Carpal Tunnel Release. Carpal tunnel release is an outpatient procedure during which the transverse carpal ligament that is compressing the median nerve is cut. By cutting this ligament 25% more room is created in the carpal tunnel, relieving pressure on the median nerve, stopping progression of the nerve damage and allowing the median nerve to heal. Unless irreversible nerve damage is already present, a carpal tunnel release decreases the symptoms of carpal tunnel syndrome in over 95% of patients.
Are all Carpal Tunnel Releases the Same?
There are different types of carpal tunnel releases. In the past, surgeons used long incisions that crossed the wrist crease. However, these open carpal tunnel releases created more pain, stiffness, and problems than was necessary. Many surgeons currently use a ‘mini-open’ release, which is a smaller incision in the palm that doesn’t cross the wrist crease. Compared to a formal open carpal tunnel release, this has less pain associated with it.
Endoscopic Carpal Tunnel Releases are done through smaller incisions and provide the same cure from carpal tunnel syndrome that an open carpal tunnel release does, but with less pain, less weakness, fewer problems, a higher level of physical functioning and fewer days to return to work and other activities.1-3
There are two different types of endoscopic carpal tunnel release (ECTR): 1) A one-incision endoscopic carpal tunnel release and 2) a two-incision endoscopic carpal tunnel release. Both techniques use a small incision at the wrist. But the two-incision ECTR places a second incision on the palm of the hand. While it’s an improvement over the open carpal tunnel release, this 2nd palmar wound still causes additional discomfort. In addition, this second wound needs to be protected, meaning that immediately after surgery the hand is wrapped, decreasing the activities that can be immediately performed.
The least invasive technique for carpal tunnel release is a One-Incision (or single-incision) Endoscopic Carpal Tunnel Release. The incision is usually hidden in the wrist crease and there is no incision in your palm. There are no bandages over the hand because there are no incisions on the hand. Because of this, there is decreased palmar tenderness, and most patients return to work (and other worthwhile activities) sooner following one-incision endoscopic carpal tunnel release compared to following two-incision endoscopic carpal tunnel release.3 Therefore, while the two-incision ECTR may be advertised more, the one-incision ECTR is currently the least invasive technique for carpal tunnel release, the one that can get you back the quickest. So if you want to minimize down-time and get back to activities quicker, forget the hype and focus on the facts. The one-incision ECTR is the way to go.
Endoscopic Carpal Tunnel Release
1) Feuerstein M, Burrell LM, Miller VI, Lincoln A, Huang GD, Berger R: Clinical management of carpal tunnel syndrome: a 12-year review of outcomes. Am J Ind Med 35:232-45, 1999.
2) Kerr CD, Gittins ME, Sybert DR: Endoscopic versus open carpal tunnel release: clinical results. Arthroscopy 10:266-9, 1994.
3) Palmer DH, Paulson JC, Lane-Larsen CL, Peulen VK, Olson JD: Endoscopic carpal tunnel release: a comparison of two techniques with open release. Arthroscopy 9:498-508, 1993.
What Can I Expect After One-Incision Endoscopic Carpal Tunnel Release?
Because I inject Marcaine (numbing medicine) into the wound, the hand will often be numb for the entire day of surgery. Starting the day after surgery, you can type and use computers. While there are no formal activity restrictions, if you want to minimize pain and swelling, you should probably avoid heavy lifting and gripping for 6 weeks. These activities won’t cause damage, but these stresses often cause extra pain, discomfort and swelling that most people would rather avoid. However, if you need to perform work or other activities and don’t mind pain and swelling, that’s fine.
If you do develop this pain at the base of your hand (it’s called ‘pillar pain’), you can expect it to go away on its own over a few months. Or I can inject it and usually make it go away in a few days.
The wound is sealed with a superglue-like material. You can shower immediately. Afterwards, gently blot the wound dry. The glue will fall off when it’s ready. The longer it stays on, the better the wound will do. So don’t wipe the glue off or put ointment on it. Please don’t get the wound dirty or submerge it under water (like swimming, or putting your hand under water) for 10 days after surgery. There are no stitches to remove (they’re buried and absorbable).
Tingling and electrical shocks are normal following nerve release surgery. It’s how nerves heal after having been compressed for a while.
Endoscopic Carpal Tunnel Release gets rid of most of the pain and numbness in the vast majority of patients, but not in everyone. If the numbness was constant before surgery, then there was a greater amount of nerve dysfunction before surgery. If the numbness was constant before surgery, then it can take 2 years for feeling to return, if it returns at all. That’s why it’s best to have the nerve released before the symptoms are constant.
Carpal tunnel syndrome during pregnancy
Carpal tunnel syndrome is very common during pregnancy. It’s probably caused by all of the swelling and fluid shifts that child-bearing leads to. During pregnancy, extra fluid collects throughout the body, including inside the carpal tunnel. This compresses the median nerve about the wrist, leading to carpal tunnel syndrome.
Night splints can be tried to prevent the wrist from flexing down during sleep. However, these are often ineffective. We don’t operate on pregnant women, and so a carpal tunnel release is not an option until after child birth. Fortunately, a single steroid injection usually provides significant relief by decreasing the severity of symptoms for the remainder of the pregnancy. Steroid use is widely believed to be safe during pregnancy. And it’s very effective. I’ve injected many pregnant women for carpal tunnel syndrome, including pregnant pediatricians and pregnant OB/GYNs (obstetrician-gynecologists).
Once childbirth occurs, the carpal tunnel syndrome resolves in approximately 50%, and no further treatment is needed. For the other 50%, an endoscopic carpal tunnel release can be performed as soon as the new mother is no longer breast feeding. This usually provides a permanent solution to the problem.
Myths of Carpal Tunnel Syndrome
Myth #1: CTS is related to typing or computers.
Untrue. This theory is based upon very poorly done “junk science” from decades ago. Unfortunately, these studies were quoted by plaintiff attorneys and picked up by the lay press during a class-action lawsuit against keyboard manufacturers. However, more recently performed high-quality research studies have shown that not only is there no association between computer use/typing and CTS, but that people who use computers and/or keyboards more may actually have a decreased risk of CTS compared to people who do less typing.
Myth #2: CTS is related to my job.
Mainly untrue. To be a significant risk factor for CTS both high force and high repetition over a prolonged period of time need to occur. That’s why typing, which is high repetition but low force, is not a risk factor. Assembly line work and other commonly thought of “overuse occupations” are not related to CTS. Except for those with the following high risk jobs, CTS is much more likely to be due to genetic factors or personal issues (weight, age, diabetes, thyroid issues, rheumatoid diseases, etc.) than due to a job. The high risk operations are: Jackhammer operator (high-force vibration over a prolonged period of time; please note that riding in a vehicle is not the type of vibration I’m talking about here), poultry processor, meat packer, meat cutter and cake decorator. Please note that these careers have not been proven to lead to CTS, but some noted authorities have considered these occupations predisposing risk factors for CTS.
Myth #3: CTS should be worse in my right hand if I’m right-handed or worse in my left hand if I’m left-handed.
Untrue. There is no predilection for the dominant hand. Again, CTS is not due to overuse (with the few exceptions noted above), so you’re just as likely to develop it in either hand.
Myth #4: Exercises and/or therapy can help with my CTS.
Untrue. CTS is a space problem, which leads to the median nerve becoming pinched at the wrist. There’s simply no way for exercises to help carpal tunnel syndrome. Confusion occurs because many things, such as massage, exercise, a few drinks, etc. can make almost any problem feel better in the short run. But exercises and/or therapy are not curative and will make no difference in the long run.
Myth #5: Lasers or laser surgery can help CTS.
Untrue. These false claims have been totally debunked by scientific studies. And the only laser surgery that is currently done, as far as I’m aware, is in the eyes. In the rest of the body, lasers generate too much heat, kill much more tissue than does a knife and scissors, and have led to serious problems where ever they’ve been used in the arms and legs.
“Surgeon’s-eye view” of Endoscopic Carpal Tunnel Release. The blade has been deployed and is cutting the transverse carpal ligament.