OVERVIEW
On the palm side of the wrist is a small, narrow passageway where the median nerve and several other tendons travel through from the forearm into the hand and fingers. The median nerve is responsible for supplying sensation (feeling) as well as motor (movement) to parts of the hand and fingers. Carpal tunnel syndrome occurs when the median nerve gets compressed in this tight space. As a result of the nerve getting irritated, symptoms may include numbness, tingling, pain, and loss of function in the hand and arm.
CAUSES
Pressure on the median nerve causes carpal tunnel syndrome, and this can be caused by anything that reduces the space in the carpal tunnel such as the following:
- Nerve and inflammatory medical conditions (such as arthritis or diabetes)
- Overuse or repetitive stress (certain occupations are more prone, such as office workers who are constantly typing or using a mouse, dental hygienists who need to use small tools, assembly line workers who operate vibrating tools, etc.)
- Anatomical factors (the size and shape of the bones in the wrist or previous fracture or dislocation)
- Gender (women are more susceptible, perhaps because their wrists are smaller than men's)
- Changes in body fluid balances (swelling or fluid retention may occur as a result of pregnancy or menopause)
SIGNS AND SYMPTOMS
- Numbness or tingling in the first three and a half fingers (thumb, index, middle, and half of the ring finger)
- Pain or electric shock-like sensations that may radiate from the wrist into the hand or up the arm
- "Shaking out" the hands may relieve symptoms
- Weakness and clumsiness in the hand and fingers
- Tendency to drop objects due to weakness, numbness, or loss of awareness in the hand
- Worsening of symptoms with activities that require prolonged or extreme flexion of the hand and wrist (reading a book, holding a steering wheel, sleeping with the wrists bent, etc.)
PHYSIOTHERAPY TREATMENT
- Rest: Stop activities that cause pain, numbness, and tingling. You may have to rest for longer periods between aggravating activities. Avoid activities that require prolonged or extreme flexion of the hand and wrist in order to decrease compression on the median nerve.
- Activity modification: It's important to modify activities such that the wrist is not held in the same aggravating position for too long. An ergonomic assessment should be done at your workplace to determine whether your work station is set up properly. There are also ergonomic keyboards and mouses (mice?) that are more comfortable and user-friendly. Safe use of utensils, tools, and other instruments are also recommended. Stretch breaks may have to be incorporated into the work schedule to relieve tightness and tension in the forearm, hand, and fingers.
- Modalities: Icing may help to reduce inflammation and swelling in the carpal tunnel and lessen the symptoms. Other modalities such as laser and ultrasound are also beneficial in decreasing the irritability of the nerve and surrounding soft tissues.
- Acupuncture and dry needling: These techniques may be useful to relieve tension in the surrounding forearm muscles. I like using acupuncture for nerve pain as needles can be stuck along the path of the nerve. Nerves sometimes get trapped in more than one location at a time, and this explains why surgery at one site does not necessarily relieve symptoms. This hypothesis is called "double crush syndrome."
- Manual therapy: Manual therapy is performed to stretch and relieve tightness in the forearm and finger muscles. Nerve flossing or tensioning techniques may be used to free up the nerve along its course into the hand. Soft tissue work may be done on the neck as well if a patient presents with "double crush syndrome."
- Exercise: Forearm and finger stretches are important to keep the muscles loose and limber. Median nerve flossing and tensioning stretches can be performed to prevent adhesions.
- Bracing and taping: Wearing a splint or brace will help to keep the wrist in a neutral position and relieve pressure from the carpal tunnel. People that experience symptoms at nighttime might benefit from this while they sleep.
OTHER TREATMENTS
- Nonsteroidal anti-inflammatory medications
- Carpal tunnel release surgery
- Corticosteroid injections
Double Crush Syndrome
I mentioned about "double crush syndrome" a couple of times in this post. I won't go into detail here, but it's really common in people who have "carpal tunnel." The reason why I put that in quotation marks is because it is not true carpal tunnel syndrome. Double crush syndrome occurs when a nerve gets compressed in more than one location of the body. Because nerves begin in the neck and go all the way down into the fingers, there are various points where it can potentially get entrapped. This hypothesis explains why many carpal tunnel surgeries fail: if the carpal tunnel is not the only place where the nerve is compressed, then getting surgery at the wrist will not solve the problem. I'll write another post in the future just about double crush syndrome.
