Cubital and radial tunnel syndromes are not as common as their better-known cousins such as carpal tunnel syndrome, but they can also cause severe pain, numbness, tingling and muscle weakness in the arm and hand.
The common cause of all of these syndromes is excess pressure on a nerve, usually from bone or connective tissue on a nerve in the wrist, hand, or elbow. In most cases, cubital tunnel syndrome and radial tunnel syndrome can be treated with conservative methods. But in more severe cases, surgery may be required to relieve pressure on the affected nerve.
Causes and symptoms (cubital tunnel syndrome)
Cubital tunnel syndrome—also known as ulnar neuropathy—is caused by excess pressure on the ulnar nerve, which runs close to the surface of the skin at the elbow. You are more likely to develop cubital tunnel syndrome if you have the following factors:
- Repeated use of the elbow, especially on a hard surface.
- Keeping the elbow in a bent position for a long time, for example, while talking on a cell phone or sleeping with the arm bent at the elbow.
- Sometimes, cubital tunnel syndrome develops as a result of abnormal bone growth in the elbow or intense physical activity that increases pressure on the ulnar nerve. Baseball players, for example, have an increased risk of developing cubital tunnel syndrome because of the rotational motion required to hit the ball, which can lead to ulnar ligament damage and nerve injury.
Early symptoms of cubital tunnel syndrome include:
- Pain and numbness in the elbow.
- Tingling, especially in the ring and little fingers.
More severe symptoms of cubital tunnel syndrome include:
- Weakness in the ring and little fingers
- Decreased ability to flex fingers (thumb and little finger)
- Decreased hand strength
- Arm muscle atrophy
- Deformation of the hand
If any of these symptoms are present, your doctor may diagnose cubital tunnel syndrome based on a physical examination alone. In addition, it is possible to use special neurophysiological tests (such as EMG), which can determine the degree of conduction disturbance in a nerve fiber or muscle.
Diagnostics
As a rule, the diagnosis is established on the basis of the characteristic clinical manifestations described above. It is convenient for the clinician to use a number of clinical tests that allow differentiating different types of carpal tunnel syndromes. In some cases, it is necessary to conduct electroneuromyography (the speed of impulses along the nerve) to clarify the level of nerve damage. Nerve damage, space-occupying lesions or other pathological changes causing carpal tunnel syndrome can also be determined using ultrasound, thermal imaging, MRI [Horch RE et al., 1997].
Causes and symptoms (radial tunnel syndrome)
Radial tunnel syndrome is caused by increased pressure on the radial nerve, which runs in the bones and muscles of the forearm and elbow. Causes of radial tunnel syndrome include:
- Injury
- Benign tumors (lipomas)
- Bone tumors
- Inflammation of surrounding tissues
Symptoms of radial tunnel syndrome include:
- Sharp, burning or stabbing pain in the upper forearm or back of the hand, especially when trying to straighten the wrist and fingers.
- Unlike cubital tunnel syndrome and carpal tunnel syndrome, radial tunnel syndrome rarely causes numbness or tingling because the radial nerve primarily affects the muscles.
Just like with cubital tunnel syndrome, if any of these symptoms are present, your doctor may diagnose radial tunnel syndrome based on a physical examination alone. If necessary, electromyography may be prescribed to confirm the diagnosis, determine the level of damage and the degree of damage to the nerve fiber.
Causes
The anatomical narrowness of the canal is only a predisposing factor in the development of tunnel syndrome. In recent years, evidence has accumulated indicating that this anatomical feature is genetically determined. Another reason that can lead to the development of tunnel syndrome is the presence of congenital developmental anomalies in the form of additional fibrous cords, muscles and tendons, and rudimentary bone spurs. However, predisposing factors alone for the development of this disease are usually not enough. Some metabolic and endocrine diseases (diabetes mellitus, acromegaly, hypothyroidism), diseases accompanied by changes in joints, bone tissue and tendons (rheumatoid arthritis, rheumatism, gout), conditions accompanied by hormonal changes (pregnancy), space-occupying formations can contribute to the development of tunnel syndrome the nerve itself (schwannoma, neuroma) and outside the nerve (hemangioma, lipoma). The development of tunnel syndromes is facilitated by frequently repeated stereotypical movements and injuries. Therefore, the prevalence of carpal tunnel syndrome is significantly higher in people engaged in certain activities and in representatives of certain professions (for example, stenographers have carpal tunnel syndrome 3 times more often).
Causes of cubital tunnel syndrome
The cause of this particular disease is compression of the nerve in the cubital canal. In this article we do not discuss nerve injury.
There are several causes of cubital tunnel syndrome:
- repeated trauma to the ligaments and bone structures of the elbow joint that form the canal,
- intense sports,
- arthritis, arthrosis of the elbow joint
- synovitis of the elbow joint or hemarthrosis
- repeated monotonous activities,
- consequences of fractures can also be the causes of the syndrome.
For drivers, the disease can be caused by the habit of placing their elbow on the window opening of the car door. When symptoms appear, this habit will have to be eradicated.
At the computer, you should pay attention to the position of your hand when working on the keyboard and mouse. When doing this type of work, the forearm should rest completely on the tabletop. You can put something soft under the sore elbow.
Compression of the ulnar nerve in the canal can be caused by inflammatory processes not only in the nerve tissue, but also in the soft tissue component of the cubital canal wall. For example, with medial epicondylitis, inflammation in the projection of the internal epicondyle can cause swelling and compression of the nerve. Failure to consult a doctor in a timely manner and delays in starting treatment can lead to organic damage to the wall and the process becoming chronic. As a result of the thickening of the nerve sheath, the transmission of nerve impulses may become difficult, leading to loss of sensation and motor function in some muscles of the hand and forearm.
Carpal tunnel syndrome
Carpal tunnel syndrome (carpal tunnel syndrome) is the most common form of compression-ischemic neuropathy encountered in clinical practice. In the population, carpal tunnel syndrome occurs in 3% of women and 2% of men [Berzins Yu.E., 1989]. This syndrome is caused by compression of the median nerve as it passes through the carpal tunnel under the transverse carpal ligament. The exact cause of carpal tunnel syndrome is not known. The following factors most often contribute to compression of the median nerve in the wrist area: • Trauma (accompanied by local swelling, tendon stretching). • Ergonomic factors. Chronic microtraumatization (often found among construction workers), microtraumatization associated with frequent repeated movements (among typists, with constant long-term work with a computer). • Diseases and conditions accompanied by metabolic disorders, edema, tendon and bone deformities (rheumatoid arthritis, diabetes mellitus, hypothyroidism, acromegaly, amyloidosis, pregnancy). • Massive formations of the median nerve itself (neurofibroma, schwannoma) or outside it in the wrist area (hemangioma, lipoma).
Diagnosis of carpal tunnel syndrome
Your doctor will diagnose carpal tunnel syndrome by:
- studying your medical history;
- conducting a medical examination;
- Prescribing tests to test your muscles and nerves. These tests are called nerve conduction studies and electromyography (EMG). Your doctor will tell you if you need these tests.
Your doctor may also order blood tests and x-rays. All these studies are carried out in order to rule out other possible causes of your problem.
to come back to the beginning
Anatomy of the ulnar nerve and cubital tunnel
The ulnar nerve originates in the cervical plexus, being one of the three main nerves of the upper limb. It runs along the inner surface of the shoulder, then lies in the canal formed by the olecranon process, the internal epicondyle and the ligament that connects these two bone formations, forming a rather narrow cubital canal.
Next, the nerve passes through the intermuscular space of the forearm, flowing into another channel, this time on the wrist. This canal is called the Guyon Canal. It is at the level of this canal that the ulnar nerve begins to divide into 3, sometimes 4 branches, ending with the sensory branches of the 5th and inner half of the 4th fingers, as well as the motor branches of the 3-4-5 lumbrical muscles of the hand.
Treatment
In mild cases of carpal tunnel syndrome, ice compresses and a decrease in load can help. If this does not help, the following measures must be taken: 1. Immobilization of the wrist. There are special devices (splints, orthoses) that immobilize the wrist and are convenient to use (Fig. 1). Immobilization should be carried out at least overnight, and preferably for 24 hours (at least in the acute period). 2. NSAIDs. Drugs from the NSAID group will be effective if the inflammatory process dominates in the pain mechanism. 3. If the use of NSAIDs turns out to be ineffective, it is advisable to inject novocaine with hydrocortisone into the wrist area. As a rule, this procedure is very effective. 4. In outpatient settings, electrophoresis can be performed with anesthetics and corticosteroids. 5. Surgical treatment. For mild or moderate carpal tunnel syndrome, conservative treatment is more effective. In cases where all conservative treatment options have been exhausted, surgical treatment is resorted to. Surgical treatment consists of partial or complete resection of the transverse ligament and releasing the median nerve from compression. Recently, endoscopic surgical methods have been successfully used in the treatment of carpal syndrome.
Differential diagnosis
Carpal tunnel syndrome should be differentiated from arthritis of the carpo-metacarpal joint of the thumb, cervical radiculopathy, and diabetic polyneuropathy. Patients with arthritis will show characteristic bone changes on x-rays. In cervical radiculopathy, reflex, sensory and motor changes will be associated with neck pain, while in carpal tunnel syndrome these changes are limited to distal manifestations. Diabetic polyneuropathy is usually a bilateral, symmetrical process involving other nerves (not just the median nerve). At the same time, a combination of polyneuropathy and carpal tunnel syndrome in diabetes mellitus cannot be ruled out.
Pronator teres syndrome (Seyfarth syndrome)
Entrapment of the median nerve in the proximal part of the forearm between the pronator teres fascicles is called pronator syndrome.
This syndrome usually begins to appear after significant muscle activity over many hours involving the pronator and flexor digitorum muscles. Such types of activities are often found among musicians (pianists, violinists, flutists, and especially often among guitarists), dentists, and athletes [Zhulev N.M., 2005]. Long-term tissue compression is of great importance in the development of pronator teres syndrome. This can happen, for example, during deep sleep when the newlywed’s head is positioned for a long time on the partner’s forearm or shoulder. In this case, the median nerve in the pronator snuffbox is compressed, or the radial nerve in the spiral canal is compressed when the partner’s head is located on the outer surface of the shoulder (see radial nerve compression syndrome at the level of the middle third of the shoulder). In this regard, to designate this syndrome in foreign literature, the terms “honeymoon paralysis” (honeymoon paralysis, newlywed paralysis) and “lovers paralysis” (lovers paralysis) have been adopted. Pronator teres syndrome sometimes occurs in nursing mothers. In them, compression of the nerve in the area of the pronator teres occurs when the baby’s head lies on the forearm, he is breastfed, lulled to sleep, and the sleeping person is left in this position for a long time.
