Carpal tunnel syndrome is a common condition that causes pain, numbness, and tingling in the hand and arm. The condition occurs when one of the major nerves to the hand — the median nerve — is squeezed or compressed as it travels through the wrist.

The Anatomy Behind Carpal Tunnel Syndrome

The anatomy of the wrist and hand is delicate, making it easy for us to develop carpal tunnel syndrome.

  • The Median Nerve initially comes out of the neck, goes down the inner aspect of the arm, and enters into the hand through a tunnel in the palm between the thumb muscles (thenar muscles) and the muscles to the little finger (hypothenar muscles). This tunnel is known as the wrist tunnel or the Carpal Tunnel. 
  • In this tunnel are the median nerve and 9 flexor tendons (one for the thumb and two for each finger). The Median Nerve supplies sensation to the thumb, index, middle and half of the ring finger. It also supplies muscle function to the thumb or thenar muscles.

Any injuries, inflammation, or structural changes of the wrist can put increased pressure in the Carpal Tunnel. This compresses the Median Nerve, creating symptoms that are known as carpal tunnel syndrome.

The Symptoms

The symptoms of this condition include:

  • numbness over the Median Nerve distribution (thumb, index, middle and half of the ring finger)
  • tingling and burning
  • pain radiating up the arm
  • weakness of grip and dropping objects
  • often the symptoms are worse at night (due to a tendency of many people to sleep with the wrist flexed, further pressuring the nerve)

The Causes

There are many potential causes of carpal tunnel syndrome:

  • Activities or jobs that require repetitive wrist flexion, as well as gripping or finger flexion, have been associated with an increased risk of carpal tunnel syndrome
  • Trauma, such as a wrist fracture, may also result in increased pressure in the Carpal Tunnel
  • Medical conditions such as thyroid disease, amyloidosis, rheumatoid arthritis, gout, and lupus have also been associated with an increased incidence of carpal tunnel syndrome
  • In rare cases, a cyst, abnormal muscle, abnormal artery or tumor may cause carpal tunnel syndrome.

Making a Diagnosis

Confirming a diagnosis of carpal tunnel syndrome requires a doctor first obtaining a patient history and confirming the existence of the syndrome’s symptoms. An exam is then conducted to see if the symptoms can be replicated:

  • Tapping over the Median Nerve in the palm may produce tingling or discomfort, for example. This is known as a positive Tinel's Sign
  • Applying pressure over the Carpal Tunnel may also produce symptoms. This is called the Median Nerve Compression Test
  • Holding the wrist flexed at 90 degrees for over a minute may also produce numbness or tingling. This is called the Phalen's Test.

In most cases, electrodiagnostic tests will also be ordered. These tests include nerve conduction velocity tests (NCV) and electromyography (EMG).

  • During the nerve conduction velocity tests, test electrodes are applied to the skin and nerves in the upper extremity, and electricity is applied to test how fast the nerves conduct electricity. In cases of nerve compression, the speed of electrical conduction is diminished. 
  • During the EMG, electricity is applied to stimulate a muscle response. If a patient is suffering from nerve compression, however, the response of muscle to electricity is diminished.

The Treatment

The best treatment of carpal tunnel syndrome will depend on the severity of nerve compression. 

Mild Cases

  • Lifestyle Changes: Limiting any aggravating activities may be enough to decrease a patient’s symptoms if their case is mild. Additionally, wearing a wrist splint at night often helps with the night discomfort by bracing the wrist.
  • Medications: Anti-inflammatories can be helpful in reducing inflammation inside the Carpal Tunnel. Cortisone injections have also been shown in several studies to help mild cases of Carpal Tunnel Syndrome. (However, there is a risk of nerve injury and higher rates of recurrence when injections are used.)
  • Nutrition: Vitamin B12 has been shown in several studies to reduce nerve irritation. 

Severe Cases

In severe cases of Carpal Tunnel Syndrome, and when significant symptoms persist despite conservative treatment, surgery will be needed.

Surgery for this condition is called a Carpal Tunnel Release. In this surgery the ligament over the top of the Carpal Tunnel, called the Transverse Carpal Ligament, is cut or incised, which increases the diameter of the Carpal Tunnel by approximately 29%. This takes the pressure off the nerve and relieves the symptoms of the syndrome. The skin is then closed. 

This procedure is performed on an outpatient basis, with local standby or "twilight" anesthesia. A small dressing and splint are applied. The fingers are free and the patient can perform simple activities such as dressing and eating. 

The hand must remain dry for two weeks while the incision heals. There is no heavy lifting or carrying for two weeks. At two weeks postoperatively, the sutures are removed and the patient may wash the hand. They may then progressively use the hand for heavier activities. They may return to work when comfortable performing activities. This is usually before 6 weeks.

Using this standard technique, the complications are very minimal. The possible problems that may occur are complications related to anesthesia, wound healing problems or infection, failure of the sensation to completely return, and soreness in the palm known as pillar pain.

More Information About Surgery

In addition to the standard surgical technique described above, there are various” endoscopic" techniques for a Carpal Tunnel Release procedure, using one or two incisions. In these techniques an incision is made, a scope is introduced into the Carpal Tunnel, and a knife is used to cut the Transverse Carpal Ligament. 

The theoretical short-term advantages of these techniques are smaller incisions, faster return to work and decreased discomfort in the palm. In no cases, however, do the authors of these techniques claim any significant long-term advantage over the standard technique.

There are also some disadvantages to these techniques. Visualization of the entire Carpal Tunnel and its contents are limited. This does not allow the surgeon to address all causes for the Carpal Tunnel Syndrome. Incomplete release of the ligament is a possible side effect of the procedure. This can result in the failure of symptoms to improve or actual worsening and the need for repeat surgery. Injury or lacerations of branches of the median nerve have also been noted.

All of these above complications from endoscopic Carpal Tunnel Release done elsewhere have been treated by us. Although trained to perform both techniques, I, Dr. Bowman, am unwilling to accept the increased surgical risks with endoscopic Carpal Tunnel Release for my patients. I prefer to perform the time tested standard procedure.