Carpal Tunnel Syndrome

CARPAL TUNNEL AND OTHER TUNNEL, TENDON AND INFLAMMATORY SYNDROMES

By: John Toton, MD – Orthopaedic Surgery

There are many wrist and hand symptoms related to the multiple tunnels that tendons, nerves, and blood vessels pass through. Wherever there is a “crease” in one’s wrist, palm, or fingers on the flexor/volar side, there is a tunnel that these structures must pass through. These tunnels are usually soft transverse tissue bands that keep the tendons from bowstringing as they pass from forearm to fingers, as we use our hands in grasp and function.

Carpal tunnel syndrome (CTS)
Carpal Tunnel syndrome is a condition well known to almost everyone who works with their hands. It represents a compression or relative tightness or compression of the median nerve as it passes through a “tunnel” as it enters on the flexor side of the palm.  Since nerves are very sensitive tissues to any stimulation, with any tightness, swelling, or inflammation of tendons or joints, or with fractures adjacent to the wrist tunnel, we will see symptoms first in the Median nerve, as it is the most sensitive tissue.

The median nerve or “carpal tunnel nerve” provides motor muscle function to only the muscle of the thumb, allowing the thumb to pinch the little finger with power and strength. The nerve’s primary function is sensation on the flexor side of the hand to the thumb, index, long finger, and commonly half of the ring finger, but never the fifth finger. The diagnosis is usually made clinically, by a physical examination.

In a mild case, the treatment is usually relatively simple, consisting of avoiding the aggravating problem, resting the wrist, splinting the wrist, and using anti-inflammatory medications to decrease swelling. It is common to need a diuretic to reduce edema that is in the hand and wrist. The need can be demonstrated by an inability to remove the ring from the finger early in the morning, when it is otherwise loose at the day’s end.

Other tunnel problems, including Dequervain’s tendonitis in the wrist area at the base of the thumb
Tendonitis implies an inflammation and irritation of a tendon as it attempts its active functional motion in moving an adjacent joint. On the radial (thumb side) of the wrist near the end of the radius, a group of tendons that extend and abduct (that is, bring the thumb into a spread-wide position) pass through a tunnel. This tunnel is comprised of a fibrous type tissue that keeps these tendons both in their functional proper alignment, and also keeps them from bow-stringing inefficiently. This inflammation and irritation can cause pain and localized swelling, limiting their function.

Examining for De Quervain’s tendonitis is relatively straightforward. Challenging the thumb through the range of motion described above, or placing the thumb in the palm with the remaining fingers holding that thumb in the palm and bending the wrist toward the ulna or outside puts stress on that De Quervain’s tunnel. This will cause pain in response to this motion.

Sometimes splinting is helpful in decreasing the irritation and sometimes a local cortisone injection solves the problem. Repeat cortisone injections are generally avoided, as cortisone not only decreases inflammation but can weaken the tendon tissue itself, particularly if it has been previously damaged.

Surgery can be necessary if symptoms are not resolved with the above “conservative” treatments. Surgery is usually low risk but anomalous extra tendons are sometimes found.  If all of the tendons, which sometimes can vary from as few as 3 to as many as 9 or 10 strands are not freed from the tunnel, it can leave an imperfect result. This condition and the number of tendons that are within the tunnel demonstrate the great variety of anatomy in humans, and a surgeon will take this into account as he explores the tendons in the Dequervain’s tunnel.

People also sometimes experience trigger fingers, in which the tendons passing usually on the flexor side of the hand from forearm to fingers must pass through multiple flexor tunnels.  If those tendons have been bruised or in some way swollen, the thumb or the finger can catch into a flexed position and can only be “triggered” or forced into an open position.

Treatment is similar to what is described above, including decreasing swelling, using anti-inflammatory medications, considering a steroid injection, and if ineffective, surgical release of the tunnel to allow it to heal in a loosened, less stenotic position.

Ganglions
This is a herniation of either the lining of a joint or of the synovial lining sheath of a tendon. It is usually caused by an over-production of synovial joint fluid that has the usual function of nourishing the joint or a tendon. It can also result from an injury where the tissue has been torn recently or in the past, and has weakened the lining sheath.

These appear as a lump, sometimes thought to be a “tumor” or a growth by the patient, but are commonly just a harmless nuisance.  They often resolve by themselves, and if symptomatic each can generally be treated with aspiration of the fluid by a needle by a physician, with our without a cortisone injection. However, many times they will recur in spite of aspiration, and surgery is sometimes offered, but the tradeoff is trading a scar from the surgery, and surgery itself does not guarantee against recurrence.

Arthritis

Fracture arthritis related to joint fracture imperfection (perfection is sometimes impossible to achieve when the fragments are multiple) can occur, as can degenerative arthritis, which could be described as “wear and tear” over time (that is, the aging process of a joint). Other arthritic conditions include rheumatoid or systemic arthritis, which will require specific and often specialty diagnosis and treatment. Degenerative arthritis at the base of the thumb is common, as it is the most mobile joint of the body. Bone spurring and thickening of the joints and the fingers is common as one ages and is an arthritic condition. Commonly, people with arthritis in their hands will state that they have worked hard all their life and that is the cause of degenerative arthritis, but this is not necessarily true and arthritis can occur as degenerative in nature, in people who have never abused their joints or over-used them.

Medical-Legal Considerations
As in the other articles in this series, because of the potential for severe limitation, chronic pain and disabilities if treatment is delayed or improperly performed, healthcare providers must be aware of the potentially serious risks and complications of multiple extremity issues, both minor and serious.  Timely diagnosis and treatment is essential.  A good knowledge of these conditions, with proper and timely treatment, can result in successful resolution of many of these issues, and avoid serious adverse outcomes and potential medical legal issues.