Carpal Tunnel Syndrome

 

Wrist splints are common sights. You see them on cashiers and typists, on hairdressers and bank tellers. They reflect the frequency of a problem called carpal tunnel syndrome. The carpal tunnel is an anatomical structure inside the palm of the hand at its base, and the syndrome is a collection of symptoms related to the nerve that passes through the tunnel on its way from the forearm to the hand.  The nerve is the median nerve, and it is accompanied by nine tendons that connect the muscles of the forearm to the fingers.   At times, lack of space puts pressure on the median nerve, causing aching pain in the wrist, forearm and even upper arm, and numbness or tingling in the thumb, index, third and the half of the ring finger closest to the thumb. With enough pressure the thumb muscles weaken and shrink.  Any combination of these symptoms, when caused by pressure on the median nerve in the hand, adds up to carpal tunnel syndrome.

Nerves tell you they are in trouble

Pressure on nerves that run close to the surface of the body slows conduction of the electrical impulses that carry sensory information about pain, temperature, position and touch. When your foot or arm “falls asleep,” the culprit is pressure on the nerves that carry sensory information. Pressure symptoms from the median nerve in the base of the hand are so common that many people experience them transiently when they grip a steering wheel tightly over a long period of time, or pound or push with the base of the hand. Instinctively, they respond to the feeling of fingers tingling or going to sleep with re-positioning or shaking of the hand. Only when pressure is sustained do nerves become damaged enough to cause the muscles they supply to weaken. The median nerve is a common site of chronic pressure because of the anatomy of the tunnel it must pass through to the hand.

Tunnel anatomy

The roof of the carpal tunnel is an arch of bones at the base of the hand.  The floor is a horizontal span of several tendons and ligaments between the bones on the thumb side and the little finger side of the hand. The bony arch changes shape with hand movements, especially with bringing the thumb across to the little finger side, flexing the wrist and extending the wrist.

Who gets carpal tunnel syndrome?

Because the carpal tunnel is smaller in women than in men, they are more frequently affected by symptoms from pressure on the median nerve, particularly during pregnancy when hands commonly swell.  Some medical conditions like heart or kidney failure, diabetes and growth hormone producing brain tumors may cause pressure to increase in the carpal tunnel. Inflammatory conditions like rheumatoid arthritis may also bring out symptoms. While carpal tunnel syndrome seems common in people whose occupations involve repetitive hand motions or hand pressure, such as hairdressers, typists, bakers, and jackhammer operators, rigorous studies do not fault the activities alone, but the activities combined with the individual anatomic structure, and with underlying medical conditions,  if present.

The reason for those wrist splints

Since the anatomy of the hand is responsible for carpal tunnel syndrome, relief comes from maximizing the space between the ligaments and bones. When symptoms begin, the first line of treatment is a splint that keeps the wrist aligned in a neutral position – neither flexed nor extended. It also keeps the thumb from falling in toward the ring finger. The splint’s design allows for use of the fingers and thumb and it can be worn during most activities. The crucial time for keeping it on is during sleep. When we sleep our hands naturally fall into a posture of wrist and finger flexion, and some people exaggerate this pose by tucking their hands beneath them, and even unconsciously clenching them.  Hand position at night often brings carpal tunnel symptoms to light, especially aching in the forearm, and tingling in all the fingers except the pinky.

Stretching the tunnel

Stretching the base of the hand during the day is also helpful. One good stretch is accomplished by  placing the hand flat on a wall at about shoulder height, turning the body perpendicular to the wall and stepping far enough away to straighten the elbow as much as possible. Then rotate the “eye” of the elbow, its inner bend, up to face the ceiling as much as possible. Hold the stretch for up to thirty seconds at a time.

Advil doesn’t change the anatomy

Anti-inflammatory drugs like Advil can help reduce swelling of tendon sheaths if the problem with the hand is related to injury or an underlying inflammatory condition like rheumatoid arthritis, but chronic use of anti-inflammatory drugs has not been shown to help typical, uncomplicated carpal tunnel syndrome.

When conservative measures fail

If conservative measures like splinting and stretching do not resolve carpal tunnel symptoms, surgery to expand the canal is generally successful. Some surgeries are performed through a small incision, using a scope and tools inserted directly onto the tunnel to cut away the connective tissue surrounding the nerve and tendons. Other cases require an open incision in the palm.

Diagnosis

Diagnosis of carpal runnel syndrome is relatively easy from the history alone. Conservative measures can be attempted without any other tests, provided that there are no underlying medical conditions suspected to be causing the symptoms. However, if conscientiously applied conservative measures fail, or if there is muscle weakness at the time of diagnosis, then a test called a nerve conduction study and electromyogram (EMG) will almost always confirm the diagnosis. The pressure on the nerve in the carpal tunnel causes a current applied to the nerve to be delayed in its passage to the hand, easily picked up in the nerve conduction study. Tiny needles that measure activity in the palm of the hand pick up signs of loss of nerve supply to muscles.  Muscle nerve loss does not respond as well to conservative measures as sensory symptoms like numbness and tingling do, so if the EMG demonstrates muscle nerve loss, surgery is usually recommended.

 

 

Pain in the Neck: More than a Metaphor

The cervical spine is a slender stack of fragile bones that balances the 15-17 lb. skull atop the body. Each bone has a round thick body and an arch of thinner bone projecting from its backside. The knobs of bone you feel in your own spine are just the tips of each bony arch, called the spinous processes. A wide array of ligaments, tendons and muscles hold the vertebrae together, and thirty-seven separate joints allow the head to move through a wide range of finely calibrated movements.  Arthritic changes accumulate in most necks over the years, particularly in the lower regions where most movement takes place.   In scans of people over 50, almost all will show some degree of wear and tear change in the lower vertebrae.

Aging changes in bones neck bones and ligaments

Wear and tear takes form of thickening of bony edges of the vertebrae and degeneration of the discs between them.  These changes may put pressure on the nerves that exit from the spinal cord through bony canals between the stacked vertebrae, and occasionally on the spinal cord itself, which travels through a canal formed by the centers of the stacked arches.  The ligaments that line this canal also thicken with age and create ridges inside the canal that press on the spinal cord. Degenerative changes contribute to episodic neck pain, and sometimes to more severe symptoms that require medical attention.

Why the neck hurts

The neck is second only to the low back pain as a common source of pain. Most neck pain is benign and episodic, coming from muscles, tendons, ligaments and joints. Painful episodes usually occur after some unaccustomed activity, such as painting a ceiling or suddenly twisting or bending the neck, or after sustaining a neck position for an unusual amount of time – for example, over a long drive.  Even an unaccustomed head position occasioned by wearing new bifocals can trigger a bout of stiff neck.

Other symptoms

Neck pain requires medical attention when it persists or is associated with neurological symptoms in the arms or legs.  Sensory symptoms like numbness or tingling in fingers and arms are quite common when underlying degenerative changes are present in the neck. While they may indicate pressure on nerve roots, sensory symptoms also occur when neck pain is simply a reflection of tight muscles and ligaments. The same nerve fibers that carry pain sensations also carry sensory messages and pain seems to have a kind of spillover effect into other sensory pathways.  That same spillover effect also can also cause a wide variety of sensory and pain symptoms in the head.  Headaches, pain in the back of the head, and even eye pain can be attributed to some neck problems.

Red flag symtoms: weakness and bladder control problems

Neurological symptoms indicating trouble in the motor nerves or in the spinal cord, in the setting of neck pain and degenerative changes, often indicate a more serious degree of trouble. Weakness in arm or hand muscles may mean that motor nerve roots are being squeezed as they exit the spinal column.  Weakness, fatigue and stiffness in the legs, and new trouble with bladder control are symptoms of pressure on the spinal cord. Sensory problems usually recover when the painful cause is successfully treated, but motor nerves and the spinal cord are more fragile and less reliably improve even after surgical decompression.  When motor problems are part of the picture, medical attention should be sought sooner rather than later.

Diagnosis

Careful history and physical examination are crucial to the proper diagnosis.  Diagnosis of a painful, stiff neck begins with taking a history. Most people do this before they ever see a doctor. What did I do yesterday? Did I sleep sitting up on a plane? In a strange bed? What movement makes this worse? What makes it better? Do I have any other funny symptoms? Most people also do the right thing by avoiding maneuvers that cause pain, applying either heat or ice, and even trying a soft cervical collar, which does not really immobilize the neck, but gives the head a temporary place to rest. Most often the neck improves and no medical attention is required.

Medical attention, when sought, should begin with a very detailed history, not only of the current episode, but of past problems, and other medical problems which might cause or complicate neck problems.  Important facts include history of trauma, rheumatoid arthritis, cancer, vascular disease, infections and past radiation treatment. Evaluation then moves to a physical examination, not only of the neck, but a general physical exam and a neurological exam. Imaging studies, electrical evaluation of nerves and muscles, and blood work follow under some circumstances. These include symptoms persisting more than 6 weeks, severe symptoms involving a single joint, presence of fever and weight loss, suspected fracture or dislocation, associated neurological symptoms or findings, and failure of simple treatments over a course of 4-6 weeks.

Treatment

Conservative measures are effective for treating common types of neck pain, especially if carried out conscientiously. Massage, hot or cold applications, topical pain relieving and muscle relaxing creams and intermittent use of aspirin or non-steroidal anti-inflammatory agents are all helpful but they are play a  only a supporting role. The major goal is to correct posture, not only of the neck, but of the whole spine, by strengthening and stretching of the muscles that support the spine and those that suspend and move the shoulders.   An effective exercise program, under supervision of a qualified physical therapist, involves the entire spine, as well as legs and arms.  In addition, supporting the neck’s normal curve in sleep with a good cervical pillow is crucial.

When conservative measures fail, more invasive means of treatment such as injections of anti-inflammatory and analgesic drugs are often added. Surgical treatment of neck pain problems is reserved for situations in which a nerve root or the spinal cord must be decompressed, or ones in which pain is so severe and unremitting that fusing the bones to decrease movement of the neck is considered the only option. In comparison to the number of people with neck pain at some point in their lives, surgically treated neck complaints are actually few and far between.  Considering how much the neck moves, how much wear and tear it sustains and how little protection it has, this is a remarkable measure of its resilience.

No more posts.