Pinching of the radial nerve of the right, left hand

Compression or pinching of the radial nerve - one of the three nerves of the brachial plexus that provide motor and sensory function of the hands - leads to the development of compression neuropathies, including tunnel syndromes. [1]

Epidemiology

According to some clinical data, the annual detection of a pinched radial nerve in the diagnosis of compression neuropathies is: 0.03% - compression of the posterior interosseous branch, pinching of the superficial branch - 0.003%. [2]

For comparison: carpal tunnel syndrome (carpal tunnel syndrome), caused by a pinched median nerve, is detected in 0.1-0.3% of patients with neuropathies of the upper extremities; compression of the ulnar nerve (in the form of cubital canal syndrome) is diagnosed in 0.03% of cases.

Mononeuropathy of the radial nerve, as a result of its compression, is observed in almost 12% of patients with fractures of the humerus. [3]

Causes of the pinched radial nerve

Pinching of the radial nerve is rarely diagnosed due to the similarity of the clinical picture with other types of  neuropathy of the upper extremities . [4]

Compression can occur anywhere along the course of the  radial nerve  (nervus radialis) and can have a variety of etiologies. [5]

Among the causes and risk factors for pinching it, experts note:

• long-term traumatic effects of repeated pronation and supination of the wrist and flexion-extension or swinging movements of the forearm, often associated with sports and professional activities;
• fracture of the lower or middle part of the humerus (including, with the development of post-traumatic periostitis in the region of the middle third of the shoulder, to which the nerve is adjacent);
• dislocation of the radius or elbow joint, a strong blow to the outer-back of the elbow;
• swelling of the tissues of the forearm after the installation of structures for the correct fusion of the fracture of the humerus;
• previous surgeries on the upper limb for shoulder instability, carpal tunnel syndrome, deforming arthrosis and osteoarthritis of the hand and finger joints;
• prolonged or improper use of crutches;
• the presence of cortical hyperostosis, osteoma, connective tissue tumor (lipoma) and other formations at the site of the nerve passage.

The most likely causes of a pinched radial nerve in the hand are trauma, chronic overstrain of the wrist joint, wearing a tight-fitting strap or wristwatch bracelet, the presence of a wrist hygroma pressing on the nerve  , that is, a synovial cyst in the dorsal wrist ligament, where the branch of the radial nerve just passes through canal of the wrist (canalis carpi radialis). [6], [7]

Pathogenesis

The compressive effect not only causes ischemia of the nerve fiber (that is, the blood flow to the cells decreases), but also deforms its structure. And with injuries, local edema and reactive inflammation occur.

And the pathogenesis of syndromic forms of radial nerve pinching is due to a temporary blockade of the conduction of nerve impulses - due to a decrease in the amplitude of the action potential during depolarization of the cell membranes of neurons. In this case, the processes of nerve cells (axons) remain intact. [8]

Prolonged compression of the nerve can lead to focal thinning of the myelin sheath and even loss of myelin - with irreversible damage to the nerve and loss of its functions.

Symptoms of the pinched radial nerve

Clinically, the  symptoms of damage to the radial nerve and its branches  vary depending on the location of the pinch. And the first signs for a long time can be manifested by a violation of sensitivity.

When the radial nerve is squeezed in the area of the shoulder-axillary angle (in the upper third of the shoulder), the sensitivity of the skin of the back of the hand from the shoulder to the thumb and, in part, the index and middle fingers, decreases; it is difficult to bend and straighten the arm at the elbow. A characteristic symptom is a  drooping hand  - due to paresis of the muscles of the forearm, which provide extension of the hand.

If the pinching of the radial nerve occurs in the brachioradial canal (snalis humeromuscularis), which is also called (spiral), in the area of the septum between the brachial and brachioradial muscles (in the middle of the shoulder) or closer to the lateral epicondyle of the humerus, then - to all the listed symptoms - the impossibility of rotation of the forearm is added outward and intense  neuralgic pain accompanying the extension of the arm. [9]

Pinching of the superficial branch of the radial nerve (with paresthesia and pain on the back of the hand and base of the thumb) is most often observed when it passes from the shoulder to the forearm - in the tunnel located under the tendon of the brachioradialis muscle (musculus brachioradialis).

Compression of the radial nerve at the top of the forearm (in the sub-ulnar region) in most cases occurs when it passes through the annulus fibrosus - Frose's arcade - at the beginning of the fascia canal of the forearm instep support (canalis supinatoriu). Patients with such localization of pinching complain of weakness and limited mobility of the hand and fingers, pain on the back of the wrist and in the arm below the elbow (worse at night). The diagnosis can be defined as instep support syndrome or Frose syndrome.

Typical symptoms of a pinched radial nerve in the wrist, in addition to paresthesia (numbness) in the back of the hand, include numbness and recurrent burning pain in the thumb, index and middle fingers.

As a result of the pinching of the radial nerve in the hand - in the area of the radial fossa (a depression near the base of the thumb) - local sensory disturbances and problems with the mobility of the thumb are noted. [10]

It should be borne in mind that the tremor in the hand is not associated with a pinched nerve: there are other reasons for this. Read more in the material -  When your hands are shaking .

Complications and consequences

The main consequences and complications associated with impaired conduction of nerve impulses when the radial nerve is pinched is the development of compressive  ischemic neuropathy , which is often defined as radial tunnel syndrome.

In addition to a significant limitation of the mobility of the upper limb (which cannot always be fully restored), gradual atrophy of the muscles of the  shoulder and forearm may occur .

Diagnostics of the pinched radial nerve

Patient complaints and anamnesis are an integral part of the diagnosis, but diagnosis of radial nerve compression even on the basis of symptoms can be difficult.

Therefore, in clinical neurology, there is a system of functional tests (tension of the instep support muscle during wrist flexion, elbow deviation, pronation, etc.), which each patient undergoes.

To clarify the degree of compression damage to the nerve, instrumental diagnostics is carried out - by examining nerve conduction using  electroneuromyography .

And to identify pathological changes along the nerve, as well as visualize possible formations compressing the nerve, ultrasound or MRI is performed. [11]

Differential diagnosis

The list of diseases that the differential diagnosis should take into account includes: Kerwen's tenosynovitis, thumb arthritis, radiculopathy of the sixth cervical vertebra, lateral epicondylitis (chronic inflammation of the tendons of the extensor muscles of the forearm), inflammation of the bursa of the wrist joint (bursitis), inflammation of the synovial membrane of the wrist the entire brachial plexus (injury or inflammation).

Treatment of the pinched radial nerve

Conservative treatment implies immobilization of the limb (temporary splint) - to relieve stress from the sore arm.

The main medicines are pain relievers. In order not only to relieve pain, but also to reduce swelling in cases of nerve compression in the spiral and other radial tunnels, neurologists recommend taking non-steroidal anti-inflammatory drugs (NSAIDs) -  Ibuprofen  and its analogues. 

More information -  Neuralgia tablets

Injections of corticosteroids (hydrocortisone) may be prescribed, which bring relief after one to one and a half months in almost 70% of cases, but do not guarantee complete relief from the symptoms of neuropathy.

The drug of the group of anticholinesterase parasympathomimetics Amiridin (other trade names - Axamon, Neuromidin) is injected, which helps to improve neuromuscular transmission. Contraindications to its use include bronchial asthma, angina pectoris, decreased heart rate, intestinal obstruction, exacerbation of gastric and / or duodenal ulcers. And among the side effects are noted: general weakness, dizziness and heart rhythm disturbances; increased secretion of saliva, sweat and bronchial secretions; allergic reactions. [12]

It is recommended to take B vitamins, as well as  vitamin N - lipoic acid .

Almost the entire range of procedures that physiotherapeutic treatment uses, which is necessarily carried out for neuropathies (according to the treatment protocol), includes electrical impulse stimulation, exercise therapy, massage, etc. This issue is covered in detail in the article -  Physiotherapy for neuritis and neuralgia of peripheral nerves . [13]

The last option - surgical treatment - is carried out when conservative therapy, including courses of physiotherapy, has not yielded positive results for 12 months. Surgical intervention consists of decompression of the trunk or branch of the ulnar nerve (for example, excision of scar tissue), as well as tendon or muscle transposition. More information in the material -  Surgical Pain Management

According to experts, good results of such operations are achieved, on average, in 70% of cases, and rehabilitation can last up to one and a half years - to restore motor and sensory function. At the same time, the key condition for successful rehabilitation is the implementation of physical exercises, individually prescribed by a specialist. [14]

Alternative treatment

What can alternative treatments offer in this case? Pain relief and puffiness relief with:

• alternating warm and cold compresses on painful areas; is one - a light massage of the same places with warmed camphor or mustard oil (with the addition of a few drops of rosemary, thyme or lavender essential oils);
• doing exercises that stretch and relax the muscles of the shoulder and forearm.

For the  treatment of numbness of the hands, it is  advised to make warming compresses, alternating with cold ones.

Herbal treatment, the effectiveness of which in this pathology is questionable, includes:

• compresses with decoction of autumn crocus bulbs (related to poisonous plants);
• compresses from fresh cabbage leaves (with honey), burdock leaves or garden geranium;
• for oral administration of decoctions / water infusions of peppermint, birch leaves or valerian roots.

Prevention

It is almost impossible to insure against a pinched nerve, but to minimize the risk of compression of the nervus radialis, prolonged extension of the elbow with pronation (rotation) of the forearm and flexion of the wrist should be avoided.

Forecast

Only timely and correct treatment makes it possible to give a positive prognosis when any nerve is pinched, including the radial one. [15] And recovery can take months or even years.