What is Cheiralgia Paresthetica?

The radial nerve is a nerve that can get squeezed and cause pain in many spots along its path. A specific condition related to this, called cheiralgia paresthetica or Wartenburg syndrome, is when the radial nerve gets compressed in the forearm. This was first identified by Dr. Wartenberg in 1932. The radial nerve in this part is solely responsible for feeling and doesn’t control any movements. This condition often causes symptoms like pain and a burning sensation on the top and outer side of the hand and is commonly worsened by movements like turning the hand, pinching, and gripping.

The radial nerve starts from the group of nerves called the brachial plexus located in the neck region and is made up of nerve fibers from the fifth to the eighth cervical nerves and sometimes from the first thoracic nerve. It travels down between a muscle in the upper arm (called the triceps) and a blood vessel called the axillary artery, entering the back of the arm. As it travels down, it goes around the back of the humerus bone in the upper arm, and then enters the front compartment of the upper arm. It then continues down the arm in front of the elbow between two muscles, the brachialis and the brachioradialis.

About 3 to 5 cm above a muscle in the forearm known as the supinator, the radial nerve splits into two branches: the posterior interosseous nerve and the superficial branch of the radial nerve. The superficial branch of the radial nerve goes under the ulnar side of a muscle in the forearm called the brachioradialis. It goes past the radial artery and then at around 9 cm above the bony bump on the wrist (radial styloid process), it reaches the surface between two muscles – the brachioradialis and extensor carpi radialis longus. It then divides again into two branches: the dorsomedial and dorsolateral. These travel with a vein called the cephalic vein and move across the back of the wrist and over two muscles: the abductor pollicis longus and the extensor pollicis brevis. The dorsolateral branch gives feeling to the area near the thumb joint, while the dorsomedial branch supplies sensation to the back of the hand and back of the fingers near the end knuckle joint.

What Causes Cheiralgia Paresthetica?

The radial nerve, found in your arm, can be compressed or squeezed at any point along its pathway. Since this nerve travels close to the skin’s surface at the wrist, it is at risk of being damaged by various local traumas. These can include constriction from things like tight watches or handcuffs, penetrating wounds, or pressure from damaged areas of the arm such as fractures or soft tissue growths like lipomas or ganglion cysts.

The nerve can also be accidentally injured during certain medical procedures which involve the first dorsal compartment of the wrist, the internal or percutaneous fixation of distal radius fractures, wrist arthroscopy, and external fixation placement. Other procedures like acupuncture, drawing blood from the back of the hand, cannulation (inserting a tube into a body cavity), and the removal of a radial arterial line can also impact the nerve if complications such as blood clots occur. Injections of steroids into the nearby tendon sheath for a condition called de Quervain’s tenosynovitis can also damage the nerve and make it more susceptible to further harm.

The nerve is particularly vulnerable where it moves from deep within the body to near the skin’s surface. This compression can happen due to connective tissue bands between the muscles known as the brachioradialis and extensor carpi radialis longus, and tissue rings on the dorsal brachioradialis. Extreme and repetitive twisting of the forearm, particularly over-twisting, can also trap the nerve between these muscles. As a result, the nerve does not get suppressed when the forearm twists outward, but it can be compressed when the forearm twists inward because the extensor carpi radialis longus muscle crosses beneath the brachioradialis muscle, pressing on the nerve.

Risk Factors and Frequency for Cheiralgia Paresthetica

Cheiralgia paresthetica is a nerve compression disorder that is less common compared to other similar conditions. For instance, carpal tunnel syndrome’s yearly occurrence rate is between 0.1% and 0.35%, while the ulnar nerve compression rate is 0.02%, and the radial nerve compression rate is 0.003%. Cheiralgia paresthetica is just one type of radial nerve compression syndrome, but how often it happens every year is currently unknown.

Cheiralgia paresthetica affects women four times more often than men.
It is usually seen in people between the ages of 20 to 70.
There isn’t any specific ethnic group that is more likely to have it.

Signs and Symptoms of Cheiralgia Paresthetica

Patients with certain hand, wrist, and finger conditions often experience pain, tingling, or a sensation known as paresthesias on the back and sides of their hand. These sensations can spread from the top of the forearm to the thumb, index, and long fingers. Usually, patients cannot pinpoint a specific area of pain. The pain is often described as burning or shooting, rather than dull or achy. On rare occasions, patients might experience a sensation of numbness and tingling. Depending on the cause, symptoms could be severe, occasional, or persistent. Other potential symptoms include tenderness, altered pain perception, a difference in sensation or touch, and a loss or change in the normal feelings. Certain movements, such as bending the wrist or deviating it towards the little finger, might worsen symptoms. This can be especially noticeable during pinching or gripping actions.

In a physical examination, doctors look for several things:

Visually: They check for lumps, scars, signs of outside pressure, or changes in the skin.
Sensation: The space between the thumb and index finger is a specific area linked to the radial nerve on the thumb side of the forearm.
Touch: Here, doctors check for abnormal sensitivity or response.
Vibration: They test the response to vibration and look for any abnormality.
Muscle Strength: They check for muscle weakness or signs of muscle shrinkage. Pinch and grip strength might be reduced due to pain from these activities.
Tinel Test: This is a common test where the doctor taps along the nerve to see if it causes tingling or pain.
Hoffman Test: This test evaluates for issues with the nerves that control voluntary movement.
Finkelstein Test: This test checks for a condition called de Quervain’s tenosynovitis, where the tendons on the thumb side of the wrist are inflamed.
Dellon Test: This involves hyper-rotating the forearm and bending the wrist towards the little finger with the elbow held straight by the side.
Compression Tests: These tests involve direct pressure on specific areas to see if it triggers symptoms.
Nerve block test (optional): This involves numbing the nerve with local anesthetic to see if the symptoms ease.

Testing for Cheiralgia Paresthetica

If you’re experiencing cheiralgia paresthetica, a condition that causes hand discomfort or numbness, there are several tests your doctor might use to figure out what’s going on. These tests include:

Electromyography/Nerve Conduction Study: This test measures the speed that your nerves conduct electric signals. If your nerves are working slower than they should be, this test will pick it up. Although it’s not always present, it is a good sign if it is because it can help provide precise details about where and what kind of nerve injury you might have.

Ultrasound: This imaging technique can help distinguish between different causes of wrist pain, including cheiralgia paresthetica, de Quervain tenosynovitis, and thumb carpometacarpal joint arthritis. It can also identify any areas where the nerve might be entrapped or compressed.

Plain Radiographs: A more common way of describing this test is taking an X-ray. It can identify any hard, bony areas or any orthopedic hardware that might be causing problems.

Magnetic Resonance Imaging: MRI is another type of imaging test. It is able to identify the nerve’s anatomy, including any narrowing or enlargement. Depending on the kind of MRI used, it can also identify changes in nerve itself, including swelling.

Treatment Options for Cheiralgia Paresthetica

The management of cheiralgia paresthetica, a condition that causes hand numbness, primarily involves non-surgical treatment. The first step involves removing sources of external pressure that could be causing nerve damage. Rest and avoidance of activities that worsen the symptoms are recommended. Over-the-counter anti-inflammatory drugs and certain nerve medications can also be used for symptom relief.

If initial treatments are not successful, temporary thumb splinting and injection of anti-inflammatory corticosteroids guided by ultrasound can be considered. Medical conditions that could be worsening the symptoms must also be assessed and treated. With non-surgical treatment, up to 71% of patients can expect good to excellent outcomes.

Surgery is reserved for cases where non-surgical treatment fails. It should be noted that surgical treatment should only be considered after six months of attempted non-surgical treatment to avoid any surgical complications. Various surgical techniques focus on the nerve affected by the condition, these can involve releasing the nerve, wrapping the nerve with materials like amniotic membrane, or doing a microscopic procedure inside the nerve. Other methods involve removing elements that compress the nerve like fat masses, fascial bands, bone spikes, and even making folds in the tendon.

In surgical decompression, a defined area showing maximum nerve response and tenderness is mapped based on anatomical landmarks and the most sensitive area is selected for the operation. Here, the nerve is carefully freed from bindings and any masses, bindings, or bands that could be causing nerve compression are removed. The nerve can also be loosely wrapped in an adhesive barrier such as amniotic membranes or fascial flaps. Care is taken to avoid strangling the nerve. Once the nerve is freed, the wound is closed layer by layer and a sterile dressing is applied.

After surgery, patients should begin moving the affected area early under physical therapy guidance. Any restrictions on movement are lifted two weeks after the surgery. Occupational therapy can help prevent repeat nerve compression by teaching methods to minimize scar formation and discomfort. Patients typically receive therapy for 4 to 6 weeks and see the most improvement 60 to 90 days after surgery.

De Quervain’s Tenosynovitis is a condition where the tendons on the thumb side of the wrist are inflamed. This inflammation leads to pain, swelling and tenderness around the area. Furthermore, the presence of Cheiralgia Paresthetica can sometimes cause a false positive result on a Finkelstein test used to diagnose De Quervain’s Tenosynovitis. Interestingly, up to half of people with Cheiralgia Paresthetica are also diagnosed with De Quervain’s Tenosynovitis.

Lateral Antebrachial Cutaneous Nerve Neuritis refers to inflammation of a nerve that provides sensation to the outer part of the forearm. Symptoms of this condition may sometimes be mistaken with those of other nerve issues, and it’s important to remember that the two can coexist. Tests should be performed and interpreted carefully to avoid confusion due to nerve overlap which is observable in a range of 21% to 75% of patients.

Thumb Carpometacarpal Joint Arthritis is a painful condition located in the radial (thumb side) of the wrist. It can cause weakness during movement, grip, and pinch, as well as a crackling sound with motion. Deformities of the thumb joint may also be present in some cases. However, no sensory issues are generally associated with the condition.

Proximal Nerve Lesions are issues found in areas such as the spinal cord, nerve roots, and various nerves in the arm. These lesions can cause sensory disturbances along with strength deficits.

Lastly, Intersection Syndrome refers to pain in the dorsoradial (top side) of the forearm, often accompanied by a crackling sound over a particular point in the arm where several muscles intersect. Like Thumb Carpometacarpal Joint Arthritis, this condition does not result in a sensory deficit.

What to expect with Cheiralgia Paresthetica

The results of treating cheiralgia paresthetica, a condition causing hand pain and numbness, are generally positive. Many patients find their symptoms disappear on their own. In fact, up to 71% of patients who don’t have surgery experience good to excellent outcomes. However, if non-surgical treatments don’t work, the results of surgery are variable.

Some studies show a 74% success rate with surgery, while others report more modest outcomes, with around 55% of patients still experiencing symptoms even 3.5 years after surgery. Moreover, a simple procedure to relieve pressure on the nerve doesn’t always provide dependable results. Finally, a particular procedure meant to free a trapped superficial branch of the radial nerve can lead to more frequent return of symptoms and worse outcomes compared to treatments for other similar nerve conditions.

Possible Complications When Diagnosed with Cheiralgia Paresthetica

There are several complications that could arise from surgical procedures. These include:

Unsuccessful surgical decompression: This means that the surgery did not succeed in relieving pressure in a specific area.
Persistent symptoms: This suggests that the symptoms of the initial problem continue even after surgery.
Worsening of symptoms: In some cases, the symptoms may actually get worse after surgery.
Iatrogenic nerve injury: This refers to a condition where the surgery itself causes damage to the nerves.
Injury to surrounding structures: Sometimes, structures around the surgical area may get injured during surgery.
Wound problems: This includes cases where the surgical wound does not heal properly or gets infected.

Preventing Cheiralgia Paresthetica

Cheiralgia paresthetica, a condition that causes unusual hand sensations, can typically be managed effectively with straightforward, non-surgical methods. The most crucial step in the treatment process is correctly determining the cause of the condition, particularly what is causing the hand to feel pressure. Once this cause has been identified, patients should be taught how they can relieve this pressure and instructed to steer clear of any activities that might worsen their symptoms. These simple precautions are usually enough to alleviate the symptoms for most patients.